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Noble_gas | The noble gases ( historically also the inert gases ) make a group of chemical elements with similar properties ; under standard conditions , they are all odorless , colorless , monatomic gases with very low chemical reactivity . The six noble gases that occur naturally are helium ( He ) , neon ( Ne ) , argon ( Ar ) , krypton ( Kr ) , xenon ( Xe ) , and the radioactive radon ( Rn ) . Oganesson ( Og ) is predicted to be a noble gas as well , but its chemistry has not yet been investigated . For the first six periods of the periodic table , the noble gases are exactly the members of group 18 of the periodic table . Noble gases are typically highly unreactive except when under particular extreme conditions . The inertness of noble gases makes them very suitable in applications where reactions are not wanted . For example , argon is used in light bulbs to prevent the hot tungsten filament from oxidizing ; also , helium is used in breathing gas by deep-sea divers to prevent oxygen , nitrogen and carbon dioxide ( hypercapnia ) toxicity . The properties of the noble gases can be well explained by modern theories of atomic structure : their outer shell of valence electrons is considered to be `` full '' , giving them little tendency to participate in chemical reactions , and it has been possible to prepare only a few hundred noble gas compounds . The melting and boiling points for a given noble gas are close together , differing by less than 10 C-change ; that is , they are liquids over only a small temperature range . Neon , argon , krypton , and xenon are obtained from air in an air separation unit using the methods of liquefaction of gases and fractional distillation . Helium is sourced from natural gas fields which have high concentrations of helium in the natural gas , using cryogenic gas separation techniques , and radon is usually isolated from the radioactive decay of dissolved radium , thorium , or uranium compounds ( since those compounds give off alpha particles ) . Noble gases have several important applications in industries such as lighting , welding , and space exploration . A helium-oxygen breathing gas is often used by deep-sea divers at depths of seawater over 55 m to keep the diver from experiencing oxygen toxemia , the lethal effect of high-pressure oxygen , nitrogen narcosis , the distracting narcotic effect of the nitrogen in air beyond this partial-pressure threshold , and carbon dioxide poisoning ( hypercapnia ) , the panic-inducing effect of excessive carbon dioxide in the bloodstream . After the risks caused by the flammability of hydrogen became apparent , it was replaced with helium in blimps and balloons . |
Neptune | Neptune is the eighth and farthest known planet from the Sun in the Solar System . In the Solar System , it is the fourth-largest planet by diameter , the third-most-massive planet , and the densest giant planet . Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus , which is 15 times the mass of Earth and slightly larger than Neptune.Neptune is denser and physically smaller than Uranus because Neptune 's greater mass gravitationally compresses the atmosphere more . Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 AU . It is named after the Roman god of the sea and has the astronomical symbol ♆ , a stylised version of the god Neptune 's trident . Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation . Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet . Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier . Its largest moon , Triton , was discovered shortly thereafter , though none of the planet 's remaining known 14 moons were located telescopically until the 20th century . The planet 's distance from Earth gives it a very small apparent size , making it challenging to study with Earth-based telescopes . Neptune was visited by Voyager 2 , when it flew by the planet on 25 August 1989 . The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar . Neptune 's composition can be compared and contrasted with the Solar System 's other giant planets . Like Jupiter and Saturn , Neptune 's atmosphere is composed primarily of hydrogen and helium , along with traces of hydrocarbons and possibly nitrogen , but it contains a higher proportion of `` ices '' such as water , ammonia , and methane . However , its interior , like that of Uranus , is primarily composed of ices and rock , which is why Uranus and Neptune are normally considered `` ice giants '' to emphasise this distinction . Traces of methane in the outermost regions in part account for the planet 's blue appearance . In contrast to the hazy , relatively featureless atmosphere of Uranus , Neptune 's atmosphere has active and visible weather patterns . For example , at the time of the Voyager 2 flyby in 1989 , the planet 's southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter . These weather patterns are driven by the strongest sustained winds of any planet in the Solar System , with recorded wind speeds as high as 2100 km/h . Because of its great distance from the Sun , Neptune 's outer atmosphere is one of the coldest places in the Solar System , with temperatures at its cloud tops approaching 55 K. Temperatures at the planet 's centre are approximately 5400 K. Neptune has a faint and fragmented ring system ( labelled `` arcs '' ) , which was first detected during the 1960s and confirmed by Voyager 2 . |
Natural_heritage | Natural heritage refers to the sum total of the elements of biodiversity , including flora and fauna and ecosystem types , together with associated geological structures and formations ( geodiversity ) . Heritage is that which is inherited from past generations , maintained in the present , and bestowed to future generations . The term `` natural heritage '' , derived from `` natural inheritance '' , pre-dates the term `` biodiversity . '' It is a less scientific term and more easily comprehended in some ways by the wider audience interested in conservation . The term was used in this context in the United States when Jimmy Carter set up the Georgia Heritage Trust while he was governor of Georgia ; Carter 's trust dealt with both natural and cultural heritage . It would appear that Carter picked the term up from Lyndon Johnson , who used it in a 1966 Message to Congress . ( He may have gotten the term from his wife Lady Bird Johnson who was personally interested in conservation . ) President Johnson signed the Wilderness Act of 1964 . The term `` Natural Heritage '' was picked up by the Science Division of The Nature Conservancy when , under Robert E. Jenkins , Jr. , it launched in 1974 what ultimately became the network of state natural heritage programs -- one in each state , all using the same methodology and all supported permanently by state governments because they scientifically document conservation priorities and facilitate science-based environmental reviews . When this network was extended outside the United States , the term `` Conservation Data Center ( or Centre ) '' was suggested by Guillermo Mann and came to be preferred for programs outside the US . Despite the name difference , these programs , too , use the same core methodology as the 50 state natural heritage programs . |
Narwhal | The narwhal , or narwhale ( Monodon monoceros ) , is a medium-sized toothed whale that possesses a large `` tusk '' from a protruding canine tooth . It lives year-round in the Arctic waters around Greenland , Canada , and Russia . It is one of two living species of whale in the Monodontidae family , along with the beluga whale . The narwhal males are distinguished by a long , straight , helical tusk , which is an elongated upper left canine . The narwhal was one of many species described by Carl Linnaeus in his publication Systema Naturae in 1758 . Like the beluga , narwhals are medium-sized whales . For both sexes , excluding the male 's tusk , the total body size can range from 3.95 to ; the males are slightly larger than the females . The average weight of an adult narwhal is 800 to . At around 11 to 13 years old , the males become sexually mature ; females become sexually mature at about 5 to 8 years old . Narwhals do not have a dorsal fin , and their neck vertebrae are jointed like those of other mammals , not fused as in dolphins and most whales . Found primarily in Canadian Arctic and Greenlandic and Russian waters , the narwhal is a uniquely specialized Arctic predator . In winter , it feeds on benthic prey , mostly flatfish , under dense pack ice . During the summer , narwhals mostly eat Arctic cod and Greenland halibut , with other fish such as polar cod making up the remainder of their diet . Each year , they migrate from bays into the ocean as summer comes . In the winter , the male narwhals occasionally dive up to 1,500 m in depth , with dives lasting up to 25 minutes . Narwhals , like most toothed whales , communicate with `` clicks '' , `` whistles '' , and `` knocks '' . Narwhals can live up to 50 years . They are often killed by suffocation when the sea ice freezes over . Another cause of fatality , specifically among young whales , is starvation . The current population of the narwhal is about 75,000 , so narwhals qualify for Near Threatened under the criterion of the International Union for Conservation of Nature ( IUCN ) . Narwhals have been harvested for over a thousand years by Inuit people in northern Canada and Greenland for meat and ivory , and a regulated subsistence hunt continues . |
Noachian | The Noachian is a geologic system and early time period on the planet Mars characterized by high rates of meteorite and asteroid impacts and the possible presence of abundant surface water . The absolute age of the Noachian period is uncertain but probably corresponds to the lunar Pre-Nectarian to Early Imbrian periods of 4100 to 3700 million years ago , during the interval known as the Late Heavy Bombardment . Many of the large impact basins on the Moon and Mars formed at this time . The Noachian Period is roughly equivalent to the Earth 's Hadean and early Archean eons when the first life forms likely arose . Noachian-aged terrains on Mars are prime spacecraft landing sites to search for fossil evidence of life . During the Noachian , the atmosphere of Mars was denser than it is today , and the climate possibly warm enough to allow rainfall . Large lakes and rivers were present in the southern hemisphere , and an ocean may have covered the low-lying northern plains . Extensive volcanism occurred in the Tharsis region , building up enormous masses of volcanic material ( the Tharsis bulge ) and releasing large quantities of gases into the atmosphere . Weathering of surface rocks produced a diversity of clay minerals ( phyllosilicates ) that formed under chemical conditions conducive to microbial life . |
National_Weather_Service | The National Weather Service ( NWS ) is an agency of the United States federal government that is tasked with providing weather forecasts , warnings of hazardous weather , and other weather-related products to organizations and the public for the purposes of protection , safety , and general information . It is a part of the National Oceanic and Atmospheric Administration ( NOAA ) branch of the Department of Commerce , and is headquartered in Silver Spring , Maryland ( located just outside Washington , D.C. ) . The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970 . The NWS performs its primary task through a collection of national and regional centers , and 122 local weather forecast offices ( WFOs ) . As the NWS is a government agency , most of its products are in the public domain and available free of charge . |
Natural_selection | Natural selection is the differential survival and reproduction of individuals due to differences in phenotype . It is a key mechanism of evolution , the change in heritable traits of a population over time . Charles Darwin popularised the term `` natural selection '' , and compared it with artificial selection . Variation exists within all populations of organisms . This occurs partly because random mutations arise in the genome of an individual organism , and offspring can inherit such mutations . Throughout the lives of the individuals , their genomes interact with their environments to cause variations in traits . The environment of a genome includes the molecular biology in the cell , other cells , other individuals , populations , species , as well as the abiotic environment . Individuals with certain variants of the trait may survive and reproduce more than individuals with other , less successful , variants ; therefore , the population evolves . Factors that affect reproductive success are also important , including sexual selection ( now often included in natural selection ) and fecundity selection . Natural selection acts on the phenotype , or the observable characteristics of an organism , but the genetic ( heritable ) basis of any phenotype that gives a reproductive advantage may become more common in a population . Over time , this process can result in populations that specialise for particular ecological niches ( microevolution ) and may eventually result in speciation ( the emergence of new species , macroevolution ) . In other words , natural selection is a key process in the evolution of a population . Natural selection can be contrasted with artificial selection , in which humans intentionally choose specific traits , whereas in natural selection there is no intentional choice . Natural selection is one of the cornerstones of modern biology . The concept , published by Darwin and Alfred Russel Wallace in a joint presentation of papers in 1858 , was elaborated in Darwin 's influential 1859 book On the Origin of Species by Means of Natural Selection , or the Preservation of Favoured Races in the Struggle for Life , which described natural selection as analogous to artificial selection , a process by which animals and plants with traits considered desirable by human breeders are systematically favoured for reproduction . The concept of natural selection originally developed in the absence of a valid theory of heredity ; at the time of Darwin 's writing , science had yet to develop modern theories of genetics . The union of traditional Darwinian evolution with subsequent discoveries in classical genetics formed the modern synthesis of the mid-20th century . The addition of molecular genetics has led to evolutionary developmental biology , which explains evolution at the molecular level . While genotypes can slowly change by random genetic drift , natural selection remains the primary explanation for adaptive evolution . |
National_Acid_Precipitation_Assessment_Program | In United States federal environmental legislation , the National Acid Precipitation Assessment Program ( NAPAP ) was authorized by Congress under the Acid Precipitation Act of 1980 ( P.L. 96-294 , Title VII ) because of concern that acidic deposition might contribute to adverse effects on aquatic systems ; agriculture ; forests ; fish ; wildlife and natural ecosystems ; materials such as metals , wood , paint and masonry ; and public health and welfare . Congress also expressed concern over the potential impact from long-range transport on national and international policy . Congress further directed that a comprehensive 10-year research plan be developed and guided by an Interagency Task Force consisting of representatives of 12 agencies , the directors of four National Laboratories , and four presidential appointees . Operational management evolved to a six-member Joint Chairs Council consisting of the Administrators of the National Oceanic and Atmospheric Administration ( NOAA ) and the Environmental Protection Agency ( EPA ) ; secretarial officers of the Department 's of Agriculture , Energy and Interior ; and the Chairman of the Council on Environmental Quality . Other program managers include a Director for Research for executive functions , Task Group leaders reporting jointly to the Director of Research and their agencies for Coordination of research in each major subject area , and two committees composed of the Director of Research and senior representatives of the Joint Chairs Council 's agencies , i.e. , the Interagency Science Committee and the Interagency Policy Committee . |
National_Snow_and_Ice_Data_Center | The National Snow and Ice Data Center , or NSIDC , is a United States information and referral center in support of polar and cryospheric research . NSIDC archives and distributes digital and analog snow and ice data and also maintains information about snow cover , avalanches , glaciers , ice sheets , freshwater ice , sea ice , ground ice , permafrost , atmospheric ice , paleoglaciology , and ice cores . NSIDC is part of the University of Colorado Boulder Cooperative Institute for Research in Environmental Sciences ( CIRES ) , and is affiliated with the National Oceanic and Atmospheric Administration ( NOAA ) National Geophysical Data Center through a cooperative agreement . NSIDC serves as one of twelve Distributed Active Archive Centers funded by the National Aeronautics and Space Administration to archive and distribute data from NASA 's past and current satellites and field measurement programs . NSIDC also supports the National Science Foundation through the Exchange For Local Observations and Knowledge of the Arctic ( ELOKA ) and other scientific research grants . NSIDC is also a member of the ICSU World Data System . Mark Serreze is the director of NSIDC . |
NoCO2_Certification_Program | The NoCO2 Certification Program is a ` Climate Change actions ' certification scheme administered by Australia 's Carbon Reduction Institute |
Nicholas_Shackleton | Sir Nicholas John Shackleton FRS ( 23 June 1937 -- 24 January 2006 ) was an English geologist and paleoclimatologist who specialised in the Quaternary Period . He was the son of the distinguished field geologist Robert Millner Shackleton and great-nephew of the explorer Ernest Shackleton . Educated at Cranbrook School , Kent ( thanks to the generosity of a person he called his `` fairy godmother '' as she paid his school fees ) Shackleton went on to read natural sciences at Clare College , Cambridge . He graduated with the Bachelor of Arts degree in 1961 , promoted in 1964 to Master of Arts . In 1967 Cambridge awarded him a PhD degree , for a thesis entitled `` The Measurement of Paleotemperatures in the Quaternary Era '' . Apart from periods abroad as Visiting Professor or Research Associate , Shackleton 's entire scientific career was spent at Cambridge . He became Ad hominem Professor in 1991 , in the Department of Earth Sciences , working in the Godwin Institute for Quaternary Research . Shackleton was a key figure in the field of paleoceanography , publishing over two hundred scientific papers . He was a pioneer in the use of mass spectrometry to determine changes in climate as recorded in the oxygen isotope composition of calcareous microfossils . Shackleton also found evidence that the Earth 's last magnetic field reversal was 780,000 years ago . He became internationally known , in 1976 , with the publication of a paper , with James Hays and John Imbrie , in Science entitled `` Variations in the Earth 's orbit : Pacemaker of the ice ages '' . Using ocean sediment cores , Shackleton , Hays and Imbrie demonstrated that oscillations in climate over the past few million years could be correlated with variations in the orbital and positional relationship between the Earth and the Sun ( see Milankovitch cycles ) . Much of Shackleton 's later work focused on constructing precise timescales based on matching the periodic cycles in deep-sea sediment cores to calculations of incoming sunlight at particular latitudes over geological time . This method allows a far greater level of stratigraphic precision than other dating methods , and has also helped to clarify the rates and mechanisms of aspects of climate change . In September 2000 Shackleton published an innovative study of the relationship between the oxygen isotope record of the oceans and isotope records obtained from the ice in Antarctica ( glacial effect ) . This helped to identify the relative contribution of deep water temperature changes and ice volume changes to the marine isotopic record , and also highlighted the close interdependency between carbon dioxide levels and temperature change over the last 400,000 years . In 1995 Shackleton became Director of the Godwin Institute for Quaternary Research . In 1998 he was knighted for his services to earth sciences . From 1999 to 2003 he was president of the International Union for Quaternary Research ( INQUA ) . In 2010 Nick Shackleton was one of ten scientists depicted on a set of postage stamps , in commemoration of the 350th anniversary of the Royal Society . Shackleton was chosen to represent Earth Science . Shackleton was also a skilled amateur clarinet player , and collector of woodwind instruments . During his lifetime he amassed a large collection of clarinets and related instruments . His Cambridge home became a place of pilgrimage for many players and scholars . Shackleton was internationally known as an organologist , reflected in his many journal articles , as well as his contributions to the 1980 and 2001 editions of Grove 's Dictionary of Music and Musicians , as well as the Grove Dictionary of Musical Instruments . Most of Shackleton 's substantial instrument collection , numbering over 700 instruments , was bequeathed to the University of Edinburgh together with an endowment . Part of the collection is now exhibited at the Reid Concert Hall , as part of Edinburgh University 's Collection of Historic Musical Instruments . The collection has been described in a published catalogue . In addition to his reputation in the scientific world , Shackleton was highly respected by many musicians , and a friend to many who studied at Cambridge , including Christopher Hogwood . The fine copies , by Cambridge maker Daniel Bangham , of many clarinets in Shackleton 's collection , had a significant impact on historical performance from the 1980s , and continue to be used by leading performers today . The European Association of Geochemistry quinquennially awards a Science Innovation Award medal named in his honour for work in climatology . |
Net_metering | Net metering ( or net energy metering , NEM ) allows consumers who generate some or all of their own electricity to use that electricity anytime , instead of when it is generated . This is particularly important with wind and solar , which are non-dispatchable . Monthly net metering allows consumers to use solar power generated during the day at night , or wind from a windy day later in the month . Annual net metering rolls over a net kilowatt credit to the following month , allowing solar power that was generated in July to be used in December , or wind power from March in August . Net metering policies can vary significantly by country and by state or province : if net metering is available , if and how long banked credits can be retained , and how much the credits are worth ( retail/wholesale ) . Most net metering laws involve monthly roll over of kWh credits , a small monthly connection fee , require monthly payment of deficits ( i.e. normal electric bill ) , and annual settlement of any residual credit . Unlike a feed-in tariff ( FIT ) , which requires two meters , net metering uses a single , bi-directional meter and can measure current flowing in two directions . Net metering can be implemented solely as an accounting procedure , and requires no special metering , or even any prior arrangement or notification . Net metering is an enabling policy designed to foster private investment in renewable energy . |
Nitrogen | Nitrogen is a chemical element with symbol N and atomic number 7 . It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 . Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time , Rutherford is generally accorded the credit because his work was published first . The name nitrogen was suggested by Jean-Antoine-Claude Chaptal in 1790 , when it was found that nitrogen was present in nitric acid and nitrates ; this name derives from the Greek roots νἰτρον `` nitre '' and - γεννᾶν `` to form '' . Antoine Lavoisier suggested instead the name azote , from the Greek άζωτικός `` no life '' , as it is an asphyxiant gas ; his name is instead used in many languages , such as French , Russian , and Turkish , and appears in the English names of some nitrogen compounds such as hydrazine , azides and azo compounds . Nitrogen is the lightest member of group 15 of the periodic table , often called the pnictogens . The name comes from the Greek πνίγειν `` to choke '' , directly referencing nitrogen 's asphyxiating properties . It is a common element in the universe , estimated at about seventh in total abundance in the Milky Way and the Solar System . At standard temperature and pressure , two atoms of the element bind to form dinitrogen , a colourless and odorless diatomic gas with the formula N2 . Dinitrogen forms about 78 % of Earth 's atmosphere , making it the most abundant uncombined element . Nitrogen occurs in all organisms , primarily in amino acids ( and thus proteins ) , in the nucleic acids ( DNA and RNA ) and in the energy transfer molecule adenosine triphosphate . The human body contains about 3 % nitrogen by mass , the fourth most abundant element in the body after oxygen , carbon , and hydrogen . The nitrogen cycle describes movement of the element from the air , into the biosphere and organic compounds , then back into the atmosphere . Many industrially important compounds , such as ammonia , nitric acid , organic nitrates ( propellants and explosives ) , and cyanides , contain nitrogen . The extremely strong triple bond in elemental nitrogen ( N ≡ N ) , the second strongest bond in any diatomic molecule , dominates nitrogen chemistry . This causes difficulty for both organisms and industry in converting N2 into useful compounds , but at the same time means that burning , exploding , or decomposing nitrogen compounds to form nitrogen gas releases large amounts of often useful energy . Synthetically produced ammonia and nitrates are key industrial fertilisers , and fertiliser nitrates are key pollutants in the eutrophication of water systems . Apart from its use in fertilisers and energy-stores , nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric and cyanoacrylate used in superglue . Nitrogen is a constituent of every major pharmacological drug class , including antibiotics . Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules : for example , the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide . Many notable nitrogen-containing drugs , such as the natural caffeine and morphine or the synthetic amphetamines , act on receptors of animal neurotransmitters . |
National_security | National Security is a concept that a government , along with its parliaments , should protect the state and its citizens against all kind of `` national '' crises through a variety of power projections , such as political power , diplomacy , economic power , military might , and so on . The concept developed all in the United States after World War II . Initially focusing on military might , it now encompasses a broad range of facets , all of which impinge on the non-military or economic security of the nation and the values espoused by the national society . Accordingly , in order to possess national security , a nation needs to possess economic security , energy security , environmental security , etc. . Security threats involve not only conventional foes such as other nation-states but also non-state actors such as violent non-state actors , narcotic cartels , multinational corporations and non-governmental organisations ; some authorities include natural disasters and events causing severe environmental damage in this category . Measures taken to ensure national security include : using diplomacy to rally allies and isolate threats marshalling economic power to facilitate or compel cooperation maintaining effective armed forces implementing civil defense and emergency preparedness measures ( including anti-terrorism legislation ) ensuring the resilience and redundancy of critical infrastructure using intelligence services to detect and defeat or avoid threats and espionage , and to protect classified information using counterintelligence services or secret police to protect the nation from internal threats There is no single universally accepted definition of national security . The variety of definitions provide an overview of the many usages of this concept . The concept still remains ambiguous , having originated from simpler definitions which initially emphasised the freedom from military threat and political coercion to later increase in sophistication and include other forms of non-military security as suited the circumstances of the time . A typical dictionary definition , in this case from the Macmillan Dictionary ( online version ) , defines the term as `` the protection or the safety of a country 's secrets and its citizens '' emphasising the overall security of a nation and a nation state . Walter Lippmann , in 1943 , defined it in terms of war saying that `` a nation has security when it does not have to sacrifice its legitimate ínterests to avoid war , and is able , if challenged , to maintain them by war '' . A later definition by Harold Lasswell , a political scientist , in 1950 , looks at national security from almost the same aspect , that of external coercion : `` The distinctive meaning of national security means freedom from foreign dictation . '' In 1960 , Arnold Wolfers , while recognising the need to segregate the subjectivity of the conceptual idea from the objectivity , talks of threats to acquired values : `` An ambiguous symbol meaning different things to different people . National security objectively means the absence of threats to acquired values and subjectively , the absence of fear that such values will be attacked . '' The 1996 definition propagated by the National Defence College of India accretes the elements of national power : `` National security is an appropriate and aggressive blend of political resilience and maturity , human resources , economic structure and capacity , technological competence , industrial base and availability of natural resources and finally the military might . '' Harold Brown , U.S. Secretary of Defense from 1977 to 1981 in the Carter administration , enlarged the definition of national security by including elements such as economic and environmental security : National security then is the ability to preserve the nation 's physical integrity and territory ; to maintain its economic relations with the rest of the world on reasonable terms ; to preserve its nature , institution , and governance from disruption from outside ; and to control its borders.In 1990 , Harvard University history professor Charles Maier defined national security through the lens of national power : `` National security ... is best described as a capacity to control those domestic and foreign conditions that the public opinion of a given community believes necessary to enjoy its own self-determination or autonomy , prosperity and wellbeing . '' According to Prabhakaran Paleri , author of National Security , Imperatives and Challenges , national security may be defined as : The measurable state of the capability of a nation to overcome the multi-dimensional threats to the apparent well-being of its people and its survival as a nation-state at any given time , by balancing all instruments of state policy through governance , that can be indexed by computation , empirically or otherwise , and is extendable to global security by variables external to it . A concise working definition by Premaratne that paraphrases the aspects of the definitions of Brown , Romm and Paleri defines national security as Safeguarding the sovereignty , territorial integrity , citizenry and socioeconomic functionality of a nation from an aggressor intent on undermining a particular valued aspect of a nation through violent or unjust means |
Nature | Nature , in the broadest sense , is the natural , physical , or material world or universe . `` Nature '' can refer to the phenomena of the physical world , and also to life in general . The study of nature is a large part of science . Although humans are part of nature , human activity is often understood as a separate category from other natural phenomena . The word nature is derived from the Latin word natura , or `` essential qualities , innate disposition '' , and in ancient times , literally meant `` birth '' . Natura is a Latin translation of the Greek word physis , which originally related to the intrinsic characteristics that plants , animals , and other features of the world develop of their own accord . The concept of nature as a whole , the physical universe , is one of several expansions of the original notion ; it began with certain core applications of the word φύσις by pre-Socratic philosophers , and has steadily gained currency ever since . This usage continued during the advent of modern scientific method in the last several centuries . Within the various uses of the word today , `` nature '' often refers to geology and wildlife . Nature can refer to the general realm of living plants and animals , and in some cases to the processes associated with inanimate objects -- the way that particular types of things exist and change of their own accord , such as the weather and geology of the Earth . It is often taken to mean the `` natural environment '' or wilderness -- wild animals , rocks , forest , and in general those things that have not been substantially altered by human intervention , or which persist despite human intervention . For example , manufactured objects and human interaction generally are not considered part of nature , unless qualified as , for example , `` human nature '' or `` the whole of nature '' . This more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial , with the artificial being understood as that which has been brought into being by a human consciousness or a human mind . Depending on the particular context , the term `` natural '' might also be distinguished from the unnatural or the supernatural . |
New_York_Herald_Tribune | The New York Herald Tribune was a newspaper published between 1924 and 1966 . It was created in 1924 when the New York Tribune acquired the New York Herald . It was widely regarded as a `` writer 's newspaper '' and competed with the The New York Times in the daily morning market . The paper won at least nine Pulitzer Prizes during its lifetime . A `` Republican paper , a Protestant paper and a paper more representative of the suburbs than the ethnic mix of the city '' , the Tribune generally did not match the comprehensiveness of the Times coverage , but its national , international and business coverage was generally viewed among the best in the industry as was its overall style . At one time or another , the paper was home to such writers as Dorothy Thompson , Red Smith , Roger Kahn , Richard Watts , Jr. , Homer Bigart , Walter Kerr , Walter Lippmann , St. Clair McKelway , Judith Crist , Dick Schaap , Tom Wolfe , John Steinbeck , and Jimmy Breslin . Editorially , the newspaper was the voice for eastern Republicans , later referred to as Rockefeller Republicans , and espoused a pro-business , internationalist viewpoint . The paper , first owned by the Reid family , struggled financially for most of its life and rarely generated enough profit for growth or capital improvements ; the Reids subsidized the Herald Tribune through the paper 's early years . However , it enjoyed prosperity during World War II and by the end of the conflict had pulled close to the Times in ad revenue . A series of disastrous business decisions , combined with aggressive competition from the Times and poor leadership from the Reid family , left the Herald Tribune far behind its rival . In 1958 , the Reids sold the Herald Tribune to John Hay Whitney , a multimillionaire Wall Street investor who was serving as ambassador to the United Kingdom at the time . Under his leadership , the Tribune experimented with new layouts and new approaches to reporting the news , and made important contributions to the body of New Journalism that developed in the 1960s . The paper steadily revived under Whitney , but a 114-day newspaper strike stopped the Herald Tribunes gains and ushered in four years of strife with labor unions , particularly the local chapter of the International Typographical Union . Faced with mounting losses , Whitney attempted to merge the Herald Tribune with the New York World-Telegram and the New York Journal-American in the spring of 1966 ; the proposed merger led to another lengthy strike , and on August 15 , 1966 , Whitney announced the closure of the Herald Tribune . Combined with investments in the World Journal Tribune , Whitney spent $ 39.5 million ( equivalent to $ in dollars ) in his attempts to keep the newspaper alive . After the Herald Tribune closed , the Times and The Washington Post , joined by Whitney , entered an agreement to operate the International Herald Tribune , the paper 's former Paris publication . The International Herald Tribune was renamed the International New York Times in 2013 . New York magazine , created as the Herald Tribunes Sunday magazine in 1963 , was revived by editor Clay Felker in 1968 , and continues to publish today . |
New_Scientist | New Scientist is a weekly English-language international science magazine , founded in 1956 . Since 1996 it has also run a website . Sold in retail outlets and on subscription , the magazine covers current developments , news , reviews and commentary on science and technology . It also publishes speculative articles , ranging from the technical to the philosophical . A readers ' letters section discusses recent articles , and discussions also take place on the website . Readers contribute observations on examples of pseudoscience to Feedback , and offer questions and answers on scientific and technical topics to Last Word ; extracts from the latter have been compiled into several books . New Scientist , based in London , publishes editions in the UK , the United States , and Australia . |
Niagara_Frontier | The Niagara Frontier refers to the stretch of land south of Lake Ontario and Lake Erie and extending westward to Cleveland , Ohio . The term dates to the War of 1812 . This only includes the land east of the Niagara River and south of Lake Erie within the United States . The western side of the Niagara River on the Canada/Ontario side is the Niagara Peninsula and is considered part of the Golden Horseshoe . The Niagara Frontier is most commonly referred to as the land bordering the eastern Niagara River and southern shores of Lake Erie and Lake Ontario and is part of the region known as Western New York State . The Niagara Frontier also forms the eastern part of the Great Lakes North Coast , while its southeastern boundary forms what is known as ski country . The National Weather Service office in Buffalo , New York currently defines the Niagara Frontier as the following : Erie County , New York north of US 20A -- includes Buffalo , New York Niagara County , New York -- includes Niagara Falls , New York Orleans County , New York Genesee County , New York -- includes Batavia , New York Other , less common , definitions may also include the following areas : Erie County , NY south of US 20A ( also known as the Buffalo Southtowns ) Chautauqua County , New York ( particularly the area that is part of the Lake Erie watershed , north and west of the Chautauqua Ridge . This is in contrast to the southeastern part of the county , in the Conewango Creek watershed , which is NOT part of the Niagara Frontier and is instead part of the adjacent Southern Tier to the east ) Erie County , Pennsylvania -- includes Erie , Pennsylvania Ashtabula County , Ohio Lake County , Ohio Cuyahoga County , Ohio -- includes Cleveland , Ohio |
Newspaper | A newspaper is a serial publication containing news about current events , other informative articles about politics , sports , arts , and so on , and advertising . A newspaper is usually , but not exclusively , printed on relatively inexpensive , low-grade paper such as newsprint . The journalism organizations that publish newspapers are themselves often metonymically called newspapers . As of 2017 , most newspapers are now published online as well as in print . The online versions are called online newspapers or news websites . Newspapers are typically published daily or weekly . News magazines are also weekly , but they have a magazine format . General-interest newspapers typically publish news articles and feature articles on national and international news as well as local news . The news includes political events and personalities , business and finance , crime , weather , and natural disasters ; health and medicine , science , and computers and technology ; sports ; and entertainment , society , food and cooking , clothing and home fashion , and the arts . Usually the paper is divided into sections for each of those major groupings ( labeled A , B , C , and so on , with pagination prefixes yielding page numbers A1-A20 , B1-B20 , C1-C20 , and so on ) . Most traditional papers also feature an editorial page containing editorials written by an editor ( or by the paper 's editorial board ) and expressing an opinion on a public issue , opinion articles called `` op-eds '' written by guest writers ( which are typically in the same section as the editorial ) , and columns that express the personal opinions of columnists , usually offering analysis and synthesis that attempts to translate the raw data of the news into information telling the reader `` what it all means '' and persuading them to concur . Papers also include articles which have no byline ; these articles are written by staff writers . A wide variety of material has been published in newspapers . Besides the aforementioned news , information and opinions , they include weather forecasts ; criticism and reviews of the arts ( including literature , film , television , theater , fine arts , and architecture ) and of local services such as restaurants ; obituaries , birth notices and graduation announcements ; entertainment features such as crosswords , horoscopes , editorial cartoons , gag cartoons , and comic strips ; advice columns , food , and other columns ; and radio and television listings ( program schedules ) . As of 2017 , newspapers may also provide information about new movies and TV shows available on streaming video services like Netflix . Newspapers have classified ad sections where people and businesses can buy small advertisements to sell goods or services ; as of 2013 , the huge increase in Internet websites for selling goods , such as Craigslist and eBay has led to significantly less classified ad sales for newspapers . Most newspapers are businesses , and they pay their expenses with a mixture of subscription revenue , newsstand sales , and advertising revenue ( other businesses or individuals pay to place advertisements in the pages , including display ads , classified ads , and their online equivalents ) . Some newspapers are government-run or at least government-funded ; their reliance on advertising revenue and on profitability is less critical to their survival . The editorial independence of a newspaper is thus always subject to the interest of someone , whether owners , advertisers , or a government . Some newspapers with high editorial independence , high journalism quality , and large circulation are viewed as newspapers of record . Many newspapers , besides employing journalists on their own payrolls , also subscribe to news agencies ( wire services ) ( such as the Associated Press , Reuters , or Agence France-Presse ) , which employ journalists to find , assemble , and report the news , then sell the content to the various newspapers . This is a way to avoid duplicating the expense of reporting from around the world . Circa 2005 , there were approximately 6,580 daily newspaper titles in the world selling 395 million print copies a day ( in the U.S. , 1,450 titles selling 55 million copies ) . The late 2000s -- early 2010s global recession , combined with the rapid growth of free web-based alternatives , has helped cause a decline in advertising and circulation , as many papers had to retrench operations to stanch the losses . Worldwide annual revenue approached $ 100 billion in 2005-7 , then plunged during the worldwide financial crisis of 2008-9 . Revenue in 2016 fell to only $ 53 billion , hurting every major publisher as their efforts to gain online income fell far short of the goal . The decline in advertising revenues affected both the print and online media as well as all other mediums ; print advertising was once lucrative but has greatly declined , and the prices of online advertising are often lower than those of their print precursors . Besides remodeling advertising , the internet ( especially the web ) has also challenged the business models of the print-only era by crowdsourcing both publishing in general ( sharing information with others ) and , more specifically , journalism ( the work of finding , assembling , and reporting the news ) . In addition , the rise of news aggregators , which bundle linked articles from many online newspapers and other sources , influences the flow of web traffic . Increasing paywalling of online newspapers may be counteracting those effects . The oldest newspaper still published is the Ordinari Post Tijdender , which was established in Stockholm in 1645 . |
National_Aeronautics_and_Space_Act | The National Aeronautics and Space Act of 1958 is the United States federal statute that created the National Aeronautics and Space Administration ( NASA ) . The Act , which followed close on the heels of the Soviet Union 's launch of Sputnik , was drafted by the United States House Select Committee on Astronautics and Space Exploration and on July 29 , 1958 was signed by President Eisenhower . Prior to enactment , the responsibility for space exploration was deemed primarily a military venture , in line with the Soviet model that had launched the first orbital satellite . In large measure , the Act was prompted by the lack of response by a US military infrastructure that seemed incapable of keeping up the space race . The original 1958 act charged the new Agency with conducting the aeronautical and space activities of the United States `` so as to contribute materially to one or more of the following objectives : '' In 2012 , a ninth objective was added : `` The preservation of the United States preeminent position in aeronautics and space through research and technology development related to associated manufacturing processes . '' The Act abolished the National Advisory Committee for Aeronautics ( NACA ) , transferring its activities and resources to NASA effective October 1 , 1958 . The Act also created a Civilian-Military Liaison Committee , for the purpose of coordinating civilian and military space applications , and keeping NASA and the Department of Defense `` fully and currently informed '' of each other 's space activities . To this day , the United States has coordinated but separate military and civilian space programs , with much of the former involved in launching military and surveillance craft and , prior to the Partial Test Ban Treaty , planning counter-measures to the anticipated Soviet launch of nuclear warheads into space . In addition , the new law made extensive modifications to the patent law and provided that both employee inventions as well as private contractor innovations brought about through space travel would be subject to government ownership . By making the government the exclusive provider of space transport , the act effectively discouraged the private development of space travel . This situation endured until the law was modified by the Commercial Space Launch Act of 1984 , enacted to allow civilian use of NASA systems in launching space vehicles . The phrase `` We came in peace for all mankind '' , inscribed on a plaque left on the Moon by the crew of Apollo 11 , is derived from the Act 's declaration of NASA 's policy and purpose : The Congress hereby declares that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all mankind . The Act was subsequently amended to remove gender bias , so that this policy statement now reads : Devotion of Space Activities to Peaceful Purposes for Benefit of All Humankind . -- Congress declares that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all humankind . |
Neutron_monitor | A neutron monitor is a ground-based detector designed to measure the number of high-energy charged particles striking the Earth 's atmosphere from outer space . For historical reasons the incoming particles are called `` cosmic rays '' , but in fact they are particles , predominantly protons and Helium nuclei . Most of the time , a neutron monitor records galactic cosmic rays and their variation with the 11-year sunspot cycle and 22-year magnetic cycle . Occasionally the Sun emits cosmic rays of sufficient energy and intensity to raise radiation levels on Earth 's surface to the degree that they are readily detected by neutron monitors . They are termed `` ground level enhancements '' ( GLE ) . The neutron monitor was invented by University of Chicago Professor John A. Simpson in 1948 . The `` 18-tube '' NM64 monitor , which today is the international standard , is a large instrument weighing about 36 tons . |
Nominalization | In linguistics , nominalization or nominalisation is the use of a word which is not a noun ( e.g. a verb , an adjective or an adverb ) as a noun , or as the head of a noun phrase , with or without morphological transformation . The term refers , for instance , to the process of producing a noun from another part of speech by adding a derivational affix ( e.g. , the noun legalization from the verb legalize ) . Some languages simply allow verbs to be used as nouns without inflectional difference ( conversion or zero derivation ) , while others require some form of morphological transformation . English has cases of both . Nominalization is a natural part of language , but some instances of it are more noticeable than others . Writing advice sometimes focuses on avoiding uncritical overuse of nominalization . |
Nankai_megathrust_earthquakes | Nankai megathrust earthquakes are great megathrust earthquakes that occur along the Nankai megathrust -- the fault under the Nankai Trough -- which forms the plate interface between the subducting Philippine Sea Plate and the overriding Amurian Plate ( part of the Eurasian Plate ) , which dips beneath southwestern Honshu , Japan . The fault is divided into five segments in three zones , which rupture separately or in combination , and depending on location , the resulting earthquakes are subdivided by zone from west to east into Nankai earthquakes , Tōnankai earthquakes , and Tōkai earthquakes . The earthquakes occur with a return period of about 90 -- 200 years , and often occur in pairs , where a rupture along part of the fault is followed by a rupture elsewhere , notably the 1854 Ansei-Tōkai earthquake and the 1854 Ansei-Nankai earthquake the next day , and the 1944 Tōnankai earthquake , followed by the 1946 Nankaidō earthquake . In one recorded case ( the 1707 Hōei earthquake ) the fault ruptured along its entire length . All of these great earthquakes have resulted in damaging tsunamis , which are particularly damaging due to the Japanese population being concentrated on the Taiheiyō Belt , especially the coastal cities of Tokyo and Osaka , the two most populous in Japan . The area remains seismically active , and future earthquakes are anticipated , with a high risk of a Nankai earthquake in the near future , which could be potentially very damaging . |
Natural_circulation | Natural circulation refers to the ability of a fluid in a system to circulate continuously , with gravity and possible changes in heat energy . The difference of density being the only driving force . If the differences of density are caused by heat , this force is called as `` thermal head '' or `` thermal driving head . '' A fluid system designed for natural circulation will have a heat source and a heat sink . Each of these is in contact with some of the fluid in the system , but not all of it . The heat source is positioned lower than the heat sink . Most materials that are fluid at common temperatures expand when they are heated , becoming less dense . Correspondingly , they become denser when they are cooled . At the heat source of a system of natural circulation , the heated fluid becomes lighter than the fluid surrounding it , and thus rises . At the heat sink , the nearby fluid becomes denser as it cools , and is drawn downward by gravity . Together , these effects create a flow of fluid from the heat source to the heat sink and back again . Systems of natural circulation include tornadoes and other weather systems , ocean currents , and household ventilation . Some solar water heaters use natural circulation . The Gulf Stream circulates as a result of the evaporation of water . In this process , the water increases in salinity and density . In the North Atlantic Ocean , the water becomes so dense that it begins to sink down . In a nuclear reactor , natural circulation can be a design criterion . It is achieved by reducing turbulence and friction in the fluid flow ( that is , minimizing head loss ) , and by providing a way to remove any inoperative pumps from the fluid path . Also , the reactor ( as the heat source ) must be physically lower than the steam generators or turbines ( the heat sink ) . In this way , natural circulation will ensure that the fluid will continue to flow as long as the reactor is hotter than the heat sink , even when power can not be supplied to the pumps . Notable examples are the S5G and S8G United States Naval reactors , which were designed to operate at a significant fraction of full power under natural circulation , quieting those propulsion plants . The S6G reactor can not operate at power under natural circulation , but can use it to maintain emergency cooling while shut down . By the nature of natural circulation , fluids do not typically move very fast , but this is not necessarily bad , as high flow rates are not essential to safe and effective reactor operation . In modern design nuclear reactors , flow reversal is almost impossible . All nuclear reactors , even ones designed to primarily use natural circulation as the main method of fluid circulation , have pumps that can circulate the fluid in the case that natural circulation is not sufficient . |
National_Environmental_Policy_Act | The National Environmental Policy Act ( NEPA ) is a United States environmental law that promotes the enhancement of the environment and established the President 's Council on Environmental Quality ( CEQ ) . The law was enacted on January 1 , 1970 . As the bill was an early step towards the development of the United States ' environmental policy , NEPA is referred to as the `` environmental Magna Carta '' . NEPA 's most significant outcome was the requirement that all executive federal agencies prepare environmental assessments ( EAs ) and environmental impact statements ( EISs ) . These reports state the potential environmental effects of proposed federal agency actions . NEPA does not apply to the President , Congress , or the federal courts . |
Nature_worship | Nature worship is any of a variety of religious , spiritual and devotional practices that focus on the worship of natural phenomena which are attributed to the continuation of the life process . A nature deity can be in charge of nature , the biosphere , the cosmos , or the universe . Nature worship is often considered the primitive source of modern religious beliefs and can be found in theism , panentheism , pantheism , deism , polytheism , animism , totemism , shamanism , spiritism and paganism . Common to most forms of nature worship is a spiritual focus on the individual 's connection and influence on some aspects of the natural world and reverence towards it . |
New_South_Wales_Greenhouse_Gas_Abatement_Scheme | The New South Wales Greenhouse Gas Abatement Scheme ( also known as GGAS ) was a mandatory greenhouse gas emissions trading scheme that aimed to lower greenhouse gas emissions in New South Wales , Australia , to 7.27 tonnes of carbon dioxide per capita by the year 2007 , which commenced on 1 January 2003 . The Scheme imposed obligations on NSW electricity retailers and certain other parties , including large electricity users who elected to manage their own benchmark to abate a portion of the greenhouse gas emissions attributable to their sales/consumption of electricity in NSW . They did this by purchasing and acquitting NSW Greenhouse Abatement Certificates ( also known as NGACs ) created by accredited `` Abatement Certificate Providers '' ( ACPs ) . The NSW Minister for Energy , Chris Hartcher , announced closure of the scheme in April 2012 , effective from 30 June 2012 . The Greenhouse Gas Reduction Scheme ( GGAS ) closed on 30 June 2012 . The NSW Government closed GGAS to avoid duplication with the Commonwealth 's carbon price which commenced on 1 July 2012 . |
National_preserve | A National Preserve is a type of National Park Service protected area designated by the United States Congress that has characteristics normally associated with U.S. National Parks but where certain natural resource-extractive activities such as fishing , hunting , mining , and oil/gas exploration and extraction are permitted . The types of activities permitted in each national preserve varies depending on the enabling legislation of the unit . The first national preserve in the U.S. was Big Cypress National Preserve in Florida , followed soon after by Big Thicket National Preserve in Texas , both established in 1974 . National preserves in Alaska were created by a provision of the Alaska National Interest Lands Conservation Act of 1980 , allowing only regulated hunting , fishing and trapping for sport and subsistence purposes . |
New_York_metropolitan_area | The New York metropolitan area , also referred to as the Tri-State Area , includes the most populous city in the United States ( New York City ) ; Long Island and the Mid - and Lower Hudson Valley in the state of New York ; the five largest cities in New Jersey ( Newark -- the largest city in New Jersey -- Jersey City , Paterson , Elizabeth , and Edison ) and their vicinities ; six of the seven largest cities in Connecticut ( Bridgeport -- the largest city in Connecticut -- New Haven , Stamford , Waterbury , Norwalk , and Danbury ) and their vicinities ; and five counties in northeastern Pennsylvania . As per the 2015 United States Census Bureau estimates , the New York metropolitan area remains , by a significant margin , the most populous in the United States , as defined by both the Metropolitan Statistical Area ( 20.2 million residents ) and the Combined Statistical Area ( 23.7 million residents ) ; it is also one of the most populous urban agglomerations in the world , and the single largest in North America . The New York metropolitan area continues to be the premier gateway for legal immigration to the United States , with the largest foreign-born population of any metropolitan region in the world . The MSA covers 6720 sqmi , while the CSA area is 13318 sqmi , encompassing an ethnically and geographically diverse region . The New York metropolitan area 's population is larger than that of the state of New York . As a center of many industries , including finance , international trade , new and traditional media , real estate , education , fashion and entertainment , tourism , biotechnology , and manufacturing , the New York City metropolitan region is one of the most important economic regions in the world ; in 2015 , the MSA produced a gross metropolitan product ( GMP ) of nearly US$ 1.60 trillion , while in 2015 , the CSA had a GMP of over US$ 1.83 trillion , both ranking first nationally by a wide margin and behind the GDP of only nine nations and seven nations , respectively . In 2012 , the New York metropolitan area was also home to seven of the 25 wealthiest counties in the United States by median household income , according to the American Community Survey . According to Forbes , in 2014 , the New York City metropolitan area was home to eight of the top ten ZIP codes in the United States by median housing price , with six in Manhattan alone . The New York metropolitan region 's higher education network comprises hundreds of colleges and universities , including Columbia University , New York University , Princeton University , Rockefeller University , and Yale University which have been ranked among the top 35 in the world . |
Natural_hazard | A natural hazard is a natural phenomenon that might have a negative effect on people or the environment . Natural hazard events can be grouped into two broad categories . Geophysical hazards encompass geological and meteorological phenomena such as earthquakes , volcanic eruption , wildfire , cyclonic storms , flood , drought , and coastal erosion . Biological hazards can refer to a diverse array of disease and infestation . Many geophysical hazards are related ; for example , submarine earthquakes can cause tsunamis , and hurricanes can lead to coastal flooding and erosion . Floods and wildfires can result from a combination of geological , hydrological , and climatic factors . It is possible that some natural hazards are intertemporally correlated as well . An example of the division between a natural hazard and a natural disaster is that the 1906 San Francisco earthquake was a disaster , whereas living on a fault line is a hazard . Some natural hazards can be provoked or affected by anthropogenic processes ( e.g. land-use change , drainage and construction ) . |
Neutron | The neutron is a subatomic particle , symbol or , with no net electric charge and a mass slightly larger than that of a proton . Protons and neutrons , each with mass approximately one atomic mass unit , constitute the nucleus of an atom , and they are collectively referred to as nucleons . Their properties and interactions are described by nuclear physics . The nucleus consists of Z protons , where Z is called the atomic number , and N neutrons , where N is the neutron number . The atomic number defines the chemical properties of the atom , and the neutron number determines the isotope or nuclide . The terms isotope and nuclide are often used synonymously , but they are chemical and nuclear concepts , respectively . The atomic mass number , symbol A , equals Z+N . For example , carbon has atomic number 6 , and its abundant carbon-12 isotope has 6 neutrons , whereas its rare carbon-13 isotope has 7 neutrons . Some elements occur in nature with only one stable isotope , such as fluorine . Other elements occur with many stable isotopes , such as tin with ten stable isotopes . Even though it is not a chemical element , the neutron is included in the table of nuclides . Within the nucleus , protons and neutrons are bound together through the nuclear force , and neutrons are required for the stability of nuclei . Neutrons are produced copiously in nuclear fission and fusion . They are a primary contributor to the nucleosynthesis of chemical elements within stars through fission , fusion , and neutron capture processes . The neutron is essential to the production of nuclear power . In the decade after the neutron was discovered in 1932 , neutrons were used to induce many different types of nuclear transmutations . With the discovery of nuclear fission in 1938 , it was quickly realized that , if a fission event produced neutrons , each of these neutrons might cause further fission events , etc. , in a cascade known as a nuclear chain reaction . These events and findings led to the first self-sustaining nuclear reactor ( Chicago Pile-1 , 1942 ) and the first nuclear weapon ( Trinity , 1945 ) . Free neutrons , or individual neutrons free of the nucleus , are a form of ionizing radiation and , as such , are a biological hazard , depending upon dose . A small natural `` neutron background '' flux of free neutrons exists on Earth , caused by cosmic ray showers , and by the natural radioactivity of spontaneously fissionable elements in the Earth 's crust . Dedicated neutron sources like neutron generators , research reactors and spallation sources produce free neutrons for use in irradiation and in neutron scattering experiments . |
Negative_verb | A negative verb or negation verb is a type of auxiliary that is used to form the negative of a main verb . The main verb itself has no personal endings , while the negative verb takes the inflection . The English auxiliary do n't / does n't performs a similar function by acting as a negative verb that indicates whether one or multiple individuals are involved while the verb referring to the negated activity remains uninflected , e.g. `` he cares '' / `` we care '' versus `` he does n't care '' / `` we do n't care '' . |
New_Horizons | New Horizons is an interplanetary space probe that was launched as a part of NASA 's New Frontiers program . Engineered by the Johns Hopkins University Applied Physics Laboratory ( APL ) and the Southwest Research Institute ( SwRI ) , with a team led by S. Alan Stern , the spacecraft was launched in 2006 with the primary mission to perform a flyby study of the Pluto system in 2015 , and a secondary mission to fly by and study one or more other Kuiper belt objects ( KBOs ) in the decade to follow . On January 19 , 2006 , New Horizons was launched from Cape Canaveral Air Force Station directly into an Earth-and-solar escape trajectory with a speed of about 16.26 km/s . After a brief encounter with asteroid 132524 APL , New Horizons proceeded to Jupiter , making its closest approach on February 28 , 2007 , at a distance of 2.3 e6km . The Jupiter flyby provided a gravity assist that increased New Horizons speed ; the flyby also enabled a general test of New Horizons scientific capabilities , returning data about the planet 's atmosphere , moons , and magnetosphere . Most of the post-Jupiter voyage was spent in hibernation mode to preserve on-board systems , except for brief annual checkouts . On December 6 , 2014 , New Horizons was brought back online for the Pluto encounter , and instrument check-out began . On January 15 , 2015 , the New Horizons spacecraft began its approach phase to Pluto . On July 14 , 2015 , at 11:49 UTC , it flew above the surface of Pluto , making it the first spacecraft to explore the dwarf planet . On October 25 , 2016 , at 21:48 UTC , the last of the recorded data from the Pluto flyby was received from New Horizons . Having completed its flyby of Pluto , New Horizons has maneuvered for a flyby of Kuiper belt object , expected to take place on January 1 , 2019 , when it will be 43.4 AU from the Sun . |
Neolithic_Expansion | At the end of the last ice age , about 12,000 years ago , humanity entered a period of increasing technological sophistication . For reasons that are still disputed , many of the large mammals hunted by humans became extinct , driving the development of new food sources : breadmaking considerably predates this period , but people in Mesopotamia now began cultivating wild cereal and pulses . Dogs had been domesticated over thousands of years ; nomadic shepherding became possible through domestication of goats , sheep , horses , camels and cattle . About 7,000 years ago , livestock herding was sufficiently established to allow a widespread abandonment of hunter-gathering in favour of settled lifestyles . Pottery was increasingly useful , and permanent buildings , constructed from mudbrick , appeared . These technologies spread out of the Middle East through the Old World . With the arrival of bronze , stone was used less for tools and weapons and more for buildings and statues or monuments . |
Natural_disaster | A natural disaster is a major adverse event resulting from natural processes of the Earth ; examples include floods , hurricanes , tornadoes , volcanic eruptions , earthquakes , tsunamis , and other geologic processes . A natural disaster can cause loss of life or property damage , and typically leaves some economic damage in its wake , the severity of which depends on the affected population 's resilience , or ability to recover and also on the infrastructure available . An adverse event will not rise to the level of a disaster if it occurs in an area without vulnerable population . In a vulnerable area , however , such as Nepal during the 2015 earthquake , an earthquake can have disastrous consequences and leave lasting damage , requiring years to repair . |
National_Climate_Assessment | The National Climate Assessment ( NCA ) is a United States government interagency ongoing effort on climate change science conducted under the auspices of the Global Change Research Act of 1990 . The NCA is a major product of the U.S. Global Change Research Program ( USGCRP ) which coordinates a team of experts and receives input from a Federal Advisory Committee . The Fourth National Climate Assessment is being developed . For the Third National Climate Assessment , released in 2014 , USGCRP coordinated hundreds of experts and received advice from a sixty-member Federal Advisory Committee . NCA research is integrated and summarized in the mandatory ongoing National Climate Assessment Reports . The reports are `` extensively reviewed by the public and experts , including federal agencies and a panel of the National Academy of Sciences . The First National Climate Assessment was published in 2000 . The First National Climate Assessment Report was `` prepared by the National Assessment Synthesis Team ( NAST ) , an advisory committee chartered under the Federal Advisory Committee Act to help the US Global Change Research Program fulfill its mandate under the Global Change Research Act of 1990 . The National Science and Technology Council forwarded the report to the President and Congress for their consideration as required by the Global Change Research Act . Administrative support for the US Global Change Research Program is provided by the University Corporation for Atmospheric Research , which is sponsored by the National Science Foundation ( NCA 2000 ) . '' Between 2002 and 2009 , USGCRP previously known as the U.S. Climate Change Science Program ( CCSP ) , produced twenty-one Synthesis and Assessment Products ( SAPs ) . The second NCA was published in 2009 and the third was released in 2014 . NCA 's overarching goal according to their May 20 , 2011 engagement strategy summary , `` is to enhance the ability of the U.S. to anticipate , mitigate , and adapt to changes in the global environment ( NCA 2011:2 ) . '' According to the USGCRP official website the NCA , In 2013 , the President 's Climate Action Plan released by the Executive Office of the President specifically noted the importance of the National Climate Assessments in achieving the goal of `` Using Sound Science to Manage Climate Impacts '' . |
Never_events | Never events are the `` kind of mistake -LSB- i.e. , medical error -RSB- that should never happen '' in the field of medical treatment . According to the Leapfrog Group never events are defined as `` adverse events that are serious , largely preventable , and of concern to both the public and health care providers for the purpose of public accountability . '' A 2012 study reported there may be as many as 1,500 instances of one never event , the retained foreign object , per year in the United States . The same study suggests an estimated total number of surgical mistakes at just over 4,000 per year in the United States ; however , these statistics are extrapolations from small samples rather than actual event counts . |
Natural_ventilation | Natural ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems . It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces . There are two types of natural ventilation occurring in buildings : wind driven ventilation and buoyancy-driven ventilation . Wind driven ventilation arises from the different pressures created by wind around a building or structure , and openings being formed on the perimeter which then permit flow through the building . Buoyancy-driven ventilation occurs as a result of the directional buoyancy force that results from temperature differences between the interior and exterior . Since the internal heat gains which create temperature differences between the interior and exterior are created by natural processes including the heat from people , and wind effects are variable , naturally ventilated buildings are sometimes called `` breathing buildings '' . |
National_Coal_Board | The National Coal Board ( NCB ) was the statutory corporation created to run the nationalised coal mining industry in the United Kingdom . Set up under the Coal Industry Nationalisation Act 1946 , it took over the United Kingdom 's collieries on `` vesting day '' , 1 January 1947 . In 1987 the NCB was renamed the British Coal Corporation , and its assets were subsequently privatised . |
National_Farmers_Union_(United_States) | National Farmers Union ( officially Farmers Educational and Cooperative Union of America ) is a national federation of state Farmers Union organizations in the United States . It is the second largest general farm organization in the country , after Farm Bureau . The organization was founded in 1902 in Point , Texas , and is now headquartered in Washington , D.C. Today , the organization continues its original mission : to protect and enhance the economic well-being and quality of life for family farmers and ranchers and their rural communities . It does this by promoting legislation and education beneficial to farmers , and by developing cooperative buying and selling methods and businesses . The current president is Roger Johnson , and the vice president is Donn Teske . Former NFU Presidents have included Tom Buis and David Frederickson Today , National Farmers Union represents more than 200,000 family farms and ranches across the United States . There are organized chapters in 33 different states , and proposals are often started at the local level before moving up to the state and national levels . Once in the spring and once in the fall , leaders of NFU convene in Washington , D.C. , to talk with legislators about solutions to problems they are facing . They state their mission as , `` To advocate for the economic and social well-being , and quality of life of family farmers , ranchers , fishermen and consumers and their communities through education , cooperation and legislation . NFU advocates sustainable production of food , fiber , feed and fuel . '' They also state , `` NFU will continue to be the respected , influential and independent national voice and coalition leader that bridges family producers and consumers on behalf of a vibrant and growing grassroots membership . '' |
National_Auto_Sport_Association | The National Auto Sport Association ( NASA ) is an American motorsports organization promoting road racing and high-performance driver education . Founded in 1991 , NASA hosts High Performance Driving Events ( HPDE ) , automotive rallies , time trials , autocross and amateur , club-level automotive racing , divided amongst regionally based chapters within the United States . In September 2006 , NASA held its first-ever National Championships at Mid-Ohio , the former home of the SCCA 's `` Runoffs '' . The NASA National Championships are open to any driver who earns points in a minimum of five regional races ( in any NASA region or combination of regions ) . |
New_England | New England is a geographical region comprising six states of the northeast United States : Connecticut , Maine , Massachusetts , New Hampshire , Rhode Island , and Vermont . It is bordered by the state of New York to the west and south , and the Canadian provinces of New Brunswick and Quebec to the northeast and north , respectively . The Atlantic Ocean is to the east and southeast , and Long Island Sound is to the south . Boston , the capital of Massachusetts , is New England 's largest city . The largest metropolitan area is Greater Boston , which also includes Worcester ( the second-largest city in both Massachusetts and New England ) , Manchester ( the largest city in New Hampshire ) , and Providence ( the capital and largest city of Rhode Island ) , with nearly a third of the entire region 's population . In 1620 , Puritan Separatist Pilgrims from England first settled in the region , forming the Plymouth Colony , the second successful English settlement in the Americas , following the Jamestown Settlement in Virginia founded in 1607 . Ten years later , more Puritans settled north of Plymouth Colony in Boston , thus forming Massachusetts Bay Colony . Over the next 126 years , people in the region fought in four French and Indian Wars , until the British and their Iroquois allies defeated the French and their Algonquin allies in North America . In 1692 , the town of Salem , Massachusetts and surrounding areas experienced one of the most infamous cases of mass hysteria in the history of the Western Hemisphere , the Salem witch trials . In the late 18th century , political leaders from the New England Colonies known as the Sons of Liberty initiated resistance to Britain 's efforts to impose new taxes without the consent of the colonists . The Boston Tea Party was a protest to which Britain responded with a series of punitive laws stripping Massachusetts of self-government , which were termed the `` Intolerable Acts '' by the colonists . The confrontation led to the first battles of the American Revolutionary War in 1775 , and the expulsion of the British authorities from the region in spring 1776 . The region played a prominent role in the movement to abolish slavery in the United States , and was the first region of the U.S. transformed by the Industrial Revolution , centered on the Blackstone and Merrimack river valleys . The physical geography of New England is diverse for such a small area ; southeastern New England is covered by a narrow coastal plain , while the western and northern regions are dominated by the rolling hills and worn-down peaks of the northern end of the Appalachian Mountains . With the Atlantic fall line lying so close to the coast , numerous industrial cities were able to take advantage of water power along the numerous rivers , such as the Connecticut River , which bisects the region from north to south . Each state is principally subdivided into small incorporated municipalities known as towns , many of which are governed by town meetings . The only unincorporated areas in the region exist in the sparsely populated northern regions of Maine , New Hampshire , and Vermont . The region is one of the U.S. Census Bureau 's nine regional divisions and the only multi-state region with clear , consistent boundaries . It maintains a strong sense of cultural identity , although the terms of this identity are often contrasted , combining Puritanism with liberalism , agrarian life with industry , and isolation with immigration . |
National_Oceanic_and_Atmospheric_Administration | The National Oceanic and Atmospheric Administration ( NOAA ; pronounced -LSB- ˈnoʊ.ə -RSB- , like `` Noah '' ) is an American scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere . NOAA warns of dangerous weather , charts seas , guides the use and protection of ocean and coastal resources , and conducts research to improve understanding and stewardship of the environment . In addition to its civilian employees , over 11,000 as of 2015 , NOAA research and operations are supported by 379 uniformed service members who make up the NOAA Commissioned Officer Corps . NOAA traces its history to the Coast Survey established by President Thomas Jefferson in 1807 . In its present form , it combined several scientific agencies in 1970 . The Acting Under Secretary of Commerce for Oceans and Atmosphere at the Department of Commerce and the agency 's interim administrator has been Benjamin Friedman since the end of the Obama administration on January 20 , 2017 . |
National_Hurricane_Center | The National Hurricane Center ( NHC ) is the division of the United States ' National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th parallel north in the northeast Pacific Ocean and the 31st parallel north in the northern Atlantic Ocean . The agency , which is co-located with the Miami branch of the National Weather Service , is situated on the campus of Florida International University in University Park , Florida . Its Tropical Analysis and Forecast Branch ( TAFB ) routinely issues marine forecasts , in the form of graphics and high seas forecasts , for this area year round , with the Ocean Prediction Center having backup responsibility for this unit . The Technology and Science Branch ( TSB ) provides technical support for the center , which includes new infusions of technology from abroad . The Chief , Aerial Reconnaissance Coordination , All Hurricanes ( CARCAH ) unit tasks planes , for research and operational purposes , to tropical cyclones during the Atlantic hurricane season and significant weather events , including snow storms , during winter and spring . Research to improve operational forecasts is done through the Hurricane Forecast Improvement Project ( HFIP ) and Joint Hurricane Test Bed ( JHT ) initiatives . During the Atlantic and northeast Pacific hurricane seasons , the Hurricane Specialists Unit ( HSU ) issues routine tropical weather outlooks for the northeast Pacific and northern Atlantic oceans . When tropical storm or hurricane conditions are expected within 48 hours , the center issues watches and warnings via the news media and National Oceanic and Atmospheric Administration ( NOAA ) Weather Radio . Although the NHC is an agency of the United States , the World Meteorological Organization has designated it as Regional Specialized Meteorological Center for the North Atlantic and eastern Pacific , making it the clearinghouse for tropical cyclone forecasts and observations occurring in these areas . If the center loses power or becomes incapacitated , the Central Pacific Hurricane Center backs tropical cyclone advisories and tropical weather outlooks for the northeast Pacific Ocean while the Weather Prediction Center backs up tropical cyclone advisories and tropical weather outlooks for the north Atlantic Ocean . |
Nehalem_(microarchitecture) | Nehalem -LSB- nəˈheɪləm -RSB- is the codename for an Intel processor microarchitecture , which is the successor to the older Core microarchitecture . A preview system with two Nehalem processors was shown at Intel Developer Forum in 2007 , and the first processor released with the Nehalem architecture was the desktop Core i7 , which was released in November 2008 . The first generation of the Intel Core series of processors , Nehalem designs led to the introduction of Core i7 and i5 models ( no Core i3 is based on Nehalem ) . The subsequent Westmere and Sandy Bridge designs would include Core i3 processors . `` Nehalem '' is a recycled Intel codename and namesake of the Nehalem River . It is an architecture that differs radically from Netburst , while retaining some of the latter 's minor features . Nehalem-based microprocessors use the 45 nm process , run at higher clock speeds , and are more energy-efficient than Penryn microprocessors . Hyper-threading is reintroduced , along with a reduction in L2 cache size , as well as an enlarged L3 cache that is shared among all cores . Nehalem was replaced with the Sandy Bridge microarchitecture , released in January 2011 . |
Non-renewable_resource | A non-renewable resource ( also called a finite resource ) is a resource that does not renew itself at a sufficient rate for sustainable economic extraction in meaningful human time-frames . An example is carbon-based , organically-derived fuel . The original organic material , with the aid of heat and pressure , becomes a fuel such as oil or gas . Earth minerals and metal ores , fossil fuels ( coal , petroleum , natural gas ) and groundwater in certain aquifers are all considered non-renewable resources , though individual elements are almost always conserved . In contrast , resources such as timber ( when harvested sustainably ) and wind ( used to power energy conversion systems ) are considered renewable resources , largely because their localized replenishment can occur within time frames meaningful to humans . |
Naval_air_station | A naval air station is a military air base , and consists of a permanent land-based operations locations for the military aviation division of the relevant branch of a navy ( Naval aviation ) . These bases are typically populated by squadrons , groups or wings , their various support commands , and other tenant commands . The term `` Naval Air Station '' is used by many countries ' navies , such as the United States Navy , the Royal Australian Navy , the British Royal Navy , and the Indian Navy . In the case of the U.S. Navy , similar facilities in the U.S. Marine Corps are known as Marine Corps Air Stations and facilities in the U.S. Coast Guard are known as Coast Guard Air Stations . |
Natural_resource | Natural resources are resources that exist without actions of humankind . This includes all valued characteristics such as magnetic , gravitational , and electrical properties and forces . On earth it includes : sunlight , atmosphere , water , land ( includes all minerals ) along with all vegetation and animal life that naturally subsists upon or within the heretofore identified characteristics and substances . Particular areas such as the rainforest in Fatu-Hiva are often characterized by the biodiversity and geodiversity existent in their ecosystems . Natural resources may be further classified in different ways . Natural resources are materials and components ( something that can be used ) that can be found within the environment . Every man-made product is composed of natural resources ( at its fundamental level ) . A natural resource may exist as a separate entity such as fresh water , air , and as well as a living organism such as a fish , or it may exist in an alternate form that must be processed to obtain the resource such as metal ores , petroleum , and most forms of energy . There is much debate worldwide over natural resource allocations , this is particularly true during periods of increasing scarcity and shortages ( depletion and overconsumption of resources ) but also because the exportation of natural resources is the basis for many economies ( particularly for developed countries ) . Some natural resources such as sunlight and air can be found everywhere , and are known as ubiquitous resources . However , most resources only occur in small sporadic areas , and are referred to as localised resources . There are very few resources that are considered inexhaustible ( will not run out in foreseeable future ) -- these are solar radiation , geothermal energy , and air ( though access to clean air may not be ) . The vast majority of resources are theoretically exhaustible , which means they have a finite quantity and can be depleted if managed improperly . |
Nitrogen_dioxide_poisoning | Nitrogen dioxide poisoning is the illness resulting from the toxic effect of nitrogen dioxide . It usually occurs after the inhalation of the gas beyond the threshold limit value . Nitrogen dioxide is reddish-brown with very a sharp , harsh smell at high concentrations . It is colourless and odourless at lower concentration but yet harmful . Nitrogen dioxide poisoning depends on the duration , frequency and intensity of exposure . Nitrogen dioxide is an irritant of the mucous membrane linked with other air pollutant that causes pulmonary diseases such as OLD , asthma , chronic obstructive pulmonary disease and sometimes acute exacerbation of COPD and in fatal cases , deaths . Its poor solubility in water enhances its passage and its ability to pass through the moist oral mucosa of the respiratory tract . Like most toxic gases , the dose inhaled determines the toxicity on the respiratory tract . Occupational exposures constitute the highest risk of toxicity and domestic exposure is uncommon . Prolonged exposure to low concentration of the gas may have lethal effects , as can short-term exposure to high concentrations like chlorine gas poisoning . It is one of the major air pollutant capable of causing severe heath hazards such as coronary artery disease as well as stroke . Nitrogen dioxide is often released into the environment as a byproduct of fuel combustion but rarely released by spontaneous combustion . Known sources of nitrogen gas poisoning includes automobile exhaust and power stations . The toxicity may also result from non-combustible sources such as the one released from anaerobic fermentation of food grains and anaerobic digestion of biodegradable waste . The World Health Organization ( WHO ) developed a global recommendation limiting exposures to less than 20 parts per billion for chronic exposure and value less 100 ppb for one hour for acute exposure , using nitrogen dioxide as a marker for other pollutants from fuel combustion . The standards also based on the concentration of nitrogen dioxide that show a significant and profound effects on the function of the pulmonary of asthmatic patients . Historically , some cities in the United States including Chicago and Los Angeles have high levels of nitrogen dioxide but the EPA set a standard values less than 100 ppb for a one-hour exposure and less than 53 ppb for chronic exposure . |
National_park | A national park is a park in use for conservation purposes . Often it is a reserve of natural , semi-natural , or developed land that a sovereign state declares or owns . Although individual nations designate their own national parks differently , there is a common idea : the conservation of ` wild nature ' for posterity and as a symbol of national pride . An international organization , the International Union for Conservation of Nature ( IUCN ) , and its World Commission on Protected Areas , has defined `` National Park '' as its Category II type of protected areas . While this type of national park had been proposed previously , the United States established the first `` public park or pleasuring-ground for the benefit and enjoyment of the people '' , Yellowstone National Park , in 1872 . Although Yellowstone was not officially termed a `` national park '' in its establishing law , it was always termed such in practice and is widely held to be the first and oldest national park in the world . However , established by the Mongolian government in 1778 , the area surrounding Bogd Khan Uul Mountain located south of the country 's capital , Ulaanbaatar , is probably the oldest national park , predating Yellowstone by nearly a century . The first area to use `` national park '' in its creation legislation was the US 's Mackinac Island , in 1875 . Australia 's Royal National Park , established in 1879 , was the world 's third official national park . In 1895 ownership of Mackinac Island was transferred to the State of Michigan as a state park and national park status was consequently lost . As a result , Australia 's Royal National Park is by some considerations the second oldest national park now in existence . Canada established Parks Canada in 1911 , becoming the world 's first national service dedicated to protecting and presenting natural and historical treasures . The largest national park in the world meeting the IUCN definition is the Northeast Greenland National Park , which was established in 1974 . According to the IUCN , 6,555 national parks worldwide met its criteria in 2006 . IUCN is still discussing the parameters of defining a national park . National parks are almost always open to visitors . Most national parks provide outdoor recreation and camping opportunities as well as classes designed to educate the public on the importance of conservation and the natural wonders of the land in which the national park is located . |
Natural_science | Natural science is a branch of science concerned with the description , prediction , and understanding of natural phenomena , based on observational and empirical evidence . Mechanisms such as peer review and repeatability of findings are used to try to ensure the validity of scientific advances . Natural science can be divided into two main branches : life science ( or biological science ) and physical science . Physical science is subdivided into branches , including physics , space science , chemistry , and Earth science . These branches of natural science may be further divided into more specialized branches ( also known as fields ) . In Western society 's analytic tradition , the empirical sciences and especially natural sciences use tools from formal sciences , such as mathematics and logic , converting information about nature into measurements which can be explained as clear statements of the `` laws of nature '' . The social sciences also use such methods , but rely more on qualitative research , so that they are sometimes called `` soft science '' , whereas natural sciences , insofar as they emphasize quantifiable data produced , tested , and confirmed through the scientific method , are sometimes called `` hard science '' . Modern natural science succeeded more classical approaches to natural philosophy , usually traced to ancient Greece . Galileo , Descartes , Francis Bacon , and Newton debated the benefits of using approaches which were more mathematical and more experimental in a methodical way . Still , philosophical perspectives , conjectures , and presuppositions , often overlooked , remain necessary in natural science . Systematic data collection , including discovery science , succeeded natural history , which emerged in the 16th century by describing and classifying plants , animals , minerals , and so on . Today , `` natural history '' suggests observational descriptions aimed at popular audiences . |
Niagara_Escarpment | The Niagara Escarpment is a long escarpment , or cuesta , in the United States and Canada that runs predominantly east/west from New York , through Ontario , Michigan , Wisconsin , and Illinois . It is composed of the Lockport geological formation of Silurian age , and is similar to the Onondaga geological formation , which runs parallel to it and just to the south , through western New York and southern Ontario . The escarpment is most famous as the cliff over which the Niagara River plunges at Niagara Falls , for which it is named . The Niagara Escarpment is the most prominent of several escarpments formed in the bedrock of the Great Lakes Basin . From its easternmost point near Watertown , New York , the escarpment shapes in part the individual basins and landforms of Lakes Ontario , Huron , and Michigan . In Rochester , New York , three waterfalls over the escarpment are where the Genesee River flows through the city . The escarpment thence runs westward to the Niagara River , forming a deep gorge north of Niagara Falls , which itself cascades over the escarpment . In southern Ontario , it spans the Niagara Peninsula , closely following the Lake Ontario shore through the cities of St. Catharines , Hamilton , and Dundas , where it takes a sharp turn north in the town of Milton toward Georgian Bay . It then follows the Georgian Bay shore northwestwards to form the spine of the Bruce Peninsula and Manitoulin Island , as well as several smaller islands located in northern Lake Huron , where it turns westwards into the Upper Peninsula of northern Michigan , south of Sault Ste. Marie . It then extends southwards into Wisconsin following the Door Peninsula through the Bayshore Blufflands and then more inland from the western coast of Lake Michigan and Milwaukee , ending northwest of Chicago near the Wisconsin-Illinois border . |
National_Farm_Safety_&_Health_Week | National Farm Safety & Health Week is a week of commemoration , recognized annually on the third week of September in the United States . In 1944 , President Franklin D. Roosevelt signed the first proclamation for farm safety due to the high injury rate in agriculture . Agriculture is one of the most hazardous industries with a death rate of 23.2 deaths per 100,000 workers annually according to U.S. Bureau of Labor Statistics in 2013 . However , many injuries are preventable through education . Serious injuries and death can be prevented by cautiously approaching field adjustments or repairs , taking precautions to avoid slips and falls , making smart decisions while assigning tasks to youth , using and maintaining the slow moving vehicle emblem correctly , and retrofitting tractors with rollover structures . In September 2015 , President Obama gave an official proclamation to accentuate the importance of agriculture for our society and economy as well as affirm farm safety and health programs `` America 's farmers and ranchers have played a critical role in shaping our progress and forging a better future for coming generations . Through centuries of hard work , they have supplied our Nation with products and services essential to the economic and physical well-being of our society . `` Across our country , those who work on farms bolster our economy and nourish our people by providing what we need at a most human level , helping to uphold America 's founding creed : Out of many , we are one . This week , let us recognize the steadfast dedication and commitment of agricultural producers and their families , and let us reaffirm our resolve to promote their health and safety . '' Over the years , the development and dissemination of National Farm Safety & Health Week materials shifted from the National Safety Council to National Education Center for Ag Safety ( NECAS ) . NECAS is the agricultural partner for the National Safety Council and has been serving the agricultural family and business community since 1997 . Each year they provide farmers with programs and materials to promote farmer safety and health . |
Network_theory_in_risk_assessment | A network is an abstract structure capturing only the basics of connection patterns and little else . Because it is a generalized pattern , tools developed for analyzing , modeling and understanding networks can theoretically be implemented across disciplines . As long as a system can be represented by a network , there is an extensive set of tools -- mathematical , computational , and statistical -- that are well-developed and if understood can be applied to the analysis of the system of interest . Tools that are currently employed in risk assessment are often sufficient , but model complexity and limitations of computational power can tether risk assessors to involve more causal connections and account for more Black Swan event outcomes . By applying network theory tools to risk assessment , computational limitations may be overcome and result in broader coverage of events with a narrowed range of uncertainties . Decision-making processes are not incorporated into routine risk assessments ; however , they play a critical role in such processes . It is therefore very important for risk assessors to minimize confirmation bias by carrying out their analysis and publishing their results with minimal involvement of external factors such as politics , media , and advocates . In reality , however , it is nearly impossible to break the iron triangle among politicians , scientists ( in this case , risk assessors ) , and advocates and media . Risk assessors need to be sensitive to the difference between risk studies and risk perceptions . One way to bring the two closer is to provide decision-makers with data they can easily rely on and understand . Employing networks in the risk analysis process can visualize causal relationships and identify heavily-weighted or important contributors to the probability of the critical event . A `` bow-tie '' diagram , cause-and-effect diagram , Bayesian network ( a directed acyclic network ) and fault trees are few examples of how network theories can be applied in risk assessment . In epidemiology risk assessments ( Figure 7 and 9 ) , once a network model was constructed , we can visually see then quantify and evaluate the potential exposure or infection risk of people related to the well-connected patients ( Patient 1 , 6 , 35 , 130 and 127 in Figure 7 ) or high-traffic places ( Hotel M in Figure 9 ) . In ecological risk assessments ( Figure 8 ) , through a network model we can identify the keystone species and determine how widespread the impacts will extend from the potential hazards being investigated . |
National_Oceanography_Centre | The National Oceanography Centre ( NOC ) is a marine science research and technology institution based on two sites in Southampton and Liverpool , United Kingdom . It is the UK 's largest institution for integrated sea level science , coastal and deep ocean research and technology development . The NOC is wholly owned by the Natural Environment Research Council ( NERC ) and was formed in April 2010 by bringing together the NERC-managed activity at the National Oceanography Centre , Southampton and Liverpool 's Proudman Oceanographic Laboratory . The centre was set up to work in close partnership with institutions across the UK marine science community to address key science challenges , including sea level change , the oceans ' role in climate change , predicting and simulating the behaviour of the oceans through computer modelling , the future of the Arctic Ocean and long-term monitoring technologies . |
Nature_fakers_controversy | The nature fakers controversy was an early 20th-century American literary debate highlighting the conflict between science and sentiment in popular nature writing . The debate involved important American literary , environmental and political figures . Dubbed the `` War of the Naturalists '' by The New York Times , it revealed seemingly irreconcilable contemporary views of the natural world : while some nature writers of the day argued as to the veracity of their examples of anthropomorphic wild animals , others questioned an animal 's ability to adapt , learn , teach , and reason . The controversy arose from a new literary movement , which followed a growth of interest in the natural world beginning in the late 19th century , and in which the natural world was depicted in a compassionate rather than realistic light . Works such as Ernest Thompson Seton 's Wild Animals I Have Known ( 1898 ) and William J. Long 's School of the Woods ( 1902 ) popularized this new genre and emphasized sympathetic and individualistic animal characters . In March 1903 , naturalist and writer John Burroughs published an article entitled `` Real and Sham Natural History '' in the Atlantic Monthly . Lambasting writers such as Seton , Long , and Charles G. D. Roberts for their seemingly fantastical representations of wildlife , he also denounced the booming genre of realistic animal fiction as `` yellow journalism of the woods '' . Burroughs ' targets responded in defense of their work in various publications , as did their supporters , and the resulting controversy raged in the public press for nearly six years . The constant publicity given to the debate contributed to a growing distrust of the truthfulness of popular nature writing of the day , and often pitted scientist against writer . The controversy effectively ended when President Theodore Roosevelt publicly sided with Burroughs , publishing his article `` Nature Fakers '' in the September 1907 issue of Everybody 's Magazine . Roosevelt popularized the negative colloquialism by which the controversy would later be known to describe one who purposefully fabricates details about the natural world . The definition of the term later expanded to include those who depicted nature with excessive sentimentality . |
Natural_gas | Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane , but commonly including varying amounts of other higher alkanes , and sometimes a small percentage of carbon dioxide , nitrogen , hydrogen sulfide , or helium . It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years . The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas . Natural gas is a fossil fuel used as a source of energy for heating , cooking , and electricity generation . It is also used as fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals . Fossil fuel based natural gas is a non-renewable resource . Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates . Petroleum is another resource and fossil fuel found in close proximity to and with natural gas . Most natural gas was created over time by two mechanisms : biogenic and thermogenic . Biogenic gas is created by methanogenic organisms in marshes , bogs , landfills , and shallow sediments . Deeper in the earth , at greater temperature and pressure , thermogenic gas is created from buried organic material . In petroleum production gas is often burnt as flare gas . The World Bank estimates that over 150 cubic kilometers of natural gas are flared or vented annually . Before natural gas can be used as a fuel , most , but not all , must be processed to remove impurities , including water , to meet the specifications of marketable natural gas . The by-products of this processing include : ethane , propane , butanes , pentanes , and higher molecular weight hydrocarbons , hydrogen sulfide ( which may be converted into pure sulfur ) , carbon dioxide , water vapor , and sometimes helium and nitrogen . Natural gas is often informally referred to simply as `` gas '' , especially when compared to other energy sources such as oil or coal . However , it is not to be confused with gasoline , especially in North America , where the term gasoline is often shortened in colloquial usage to gas . Natural gas was used by the Chinese in about 500 BCE ( possibly even 1000 BCE ) . They discovered a way to transport gas seeping from the ground in crude pipelines of bamboo to where it was used to boil salt water to extract the salt , in the Ziliujing District of Sichuan . The world 's first industrial extraction of natural gas started at Fredonia , New York , United States in 1825 . By 2009 , 66 000 km ³ ( or 8 % ) had been used out of the total 850 000 km ³ of estimated remaining recoverable reserves of natural gas . Based on an estimated 2015 world consumption rate of about 3400 km ³ of gas per year , the total estimated remaining economically recoverable reserves of natural gas would last 250 years at current consumption rates . An annual increase in usage of 2 -- 3 % could result in currently recoverable reserves lasting significantly less , perhaps as few as 80 to 100 years . |
North_American_High | The North American High ( also Canadian High/Anticyclone , sometimes in Europe Greenland High/Anticyclone ) is an impermanent high-pressure area or anticyclone created by anticyclogenesis ( anticyclone + the Greek word genesis , meaning `` birth , origin '' ) , a formative process that occurs when cool or cold dry air settles over North America . In summer it is replaced with an Arctic Low , or if it moves to continental land , a North American Low . North American Highs move eastwards across the continent , often in the company of one or more low-pressure cells or cyclones . Its cold , dense air does not extend usually above 3 km , lower than the Canadian Rockies . Sometimes , in winter it breaks free and passes over the Rockies and brings a cold front into Southwestern United States and Mexico , freezing crops and bringing snow into Mexico 's mountains as far south as Jalisco . The high 's usual location east of the Rockies shelters it from the relatively warm Pacific Ocean and helps it maintain its strength . The average January sea level pressure at its centre is about 1,020 millibars ( 30.12 inches of mercury ) . The Canadian high often moves southeastward until it eventually reaches the Atlantic Ocean , where it merges with the Azores high . In the summer the Canadian high circulates cool , dry air to the United States east of the Rockies and parts of southern Canada . The North American High is akin to the Siberian High of Eurasia , but it is much smaller , and it has much less influence , merely affecting the weather of the Northern Hemisphere . The sea-level pressure ( atmospheric pressure ) rarely , if ever , exceeds 1055.0 millibars ( 1055.0 hectopascals ) ( hPa ) ( SI ) . Often , in the winter months , cool or cold dry air settles over the land in the vicinity of the Great Basin where it builds into a high-pressure cell or anticyclone that moves across the United States with a cold front on its leading edge . After reaching the Atlantic Ocean , the moist environment brings on changes of the qualities of the air and the dissipation of the high-pressure cell or anticyclone as the cold air warms and becomes humid . In Europe , a portion of the North American/Canadian high usually over Greenland called the Greenland high which settles over Greenland affects northern European weather and may merge with the Scandinavian High . |
Numbered_street | Not to be confused with Route number A numbered street is a street whose name is an ordinal number , as in Second Street or Tenth Avenue . Such forms are among the most common street names in North America , but also exist in other parts of the world , especially in the Middle East . Numbered streets were first used in Philadelphia and now exist in many major cities and small towns . Grid-based naming systems usually start at 1 ( but sometimes at a higher number or even at zero ) , and then proceed in numerical order . In the United States , seven out of the top ten most common street names are numbers , with the top three names being `` 2nd , '' `` 3rd , '' and `` 1st '' respectively . Some cities also have lettered '' street names . For example , Washington , D.C. , in addition to having numbered streets , also has streets identified as a letter followed by `` Street , '' going as high as the letter W. New York City ( mostly in Brooklyn ) has avenues titled `` Avenue '' followed by the respective letter of the alphabet , such as Avenue D . The idea for such a system was developed by Pierre Charles L'Enfant , who devised the system for Washington . The numbered street system is criticized for taking away the individuality from a community that a named street would provide . |
Null_hypothesis | In inferential statistics , the term `` null hypothesis '' is a general statement or default position that there is no relationship between two measured phenomena , or no association among groups . Rejecting or disproving the null hypothesis -- and thus concluding that there are grounds for believing that there is a relationship between two phenomena ( e.g. that a potential treatment has a measurable effect ) -- is a central task in the modern practice of science ; the field of statistics gives precise criteria for rejecting a null hypothesis . The null hypothesis is generally assumed to be true until evidence indicates otherwise . In statistics , it is often denoted H0 ( read `` H-nought '' , `` H-null '' , or `` H-zero '' ) . The concept of a null hypothesis is used differently in two approaches to statistical inference . In the significance testing approach of Ronald Fisher , a null hypothesis is rejected if the observed data are significantly unlikely to have occurred if the null hypothesis were true . In this case the null hypothesis is rejected and an alternative hypothesis is accepted in its place . If the data are consistent with the null hypothesis , then the null hypothesis is not rejected . In neither case is the null hypothesis or its alternative proven ; the null hypothesis is tested with data and a decision is made based on how likely or unlikely the data are . This is analogous to a criminal trial , in which the defendant is assumed to be innocent ( null is not rejected ) until proven guilty ( null is rejected ) beyond a reasonable doubt ( to a statistically significant degree ) . In the hypothesis testing approach of Jerzy Neyman and Egon Pearson , a null hypothesis is contrasted with an alternative hypothesis and the two hypotheses are distinguished on the basis of data , with certain error rates . Proponents of each approach criticize the other approach . Nowadays , though , a hybrid approach is widely practiced and presented in textbooks . The hybrid is in turn criticized as incorrect and incoherent -- for details , see Statistical hypothesis testing . Statistical inference can be done without a null hypothesis , by specifying a statistical model corresponding to each candidate hypothesis and using model selection techniques to choose the most appropriate model . ( The most common selection techniques are based on either Akaike information criterion or Bayes factor . ) |
Northern_Michigan | Northern Michigan , also known as Northern Lower Michigan or Upper Michigan ( known colloquially to residents of more southerly parts of the state and summer residents from cities such as Chicago as `` up north '' ) , is a region of the U.S. state of Michigan . A popular tourist destination , it is home to several small - to medium-sized cities , extensive state and national forests , lakes and rivers , and a large portion of Great Lakes shoreline . The region has a significant seasonal population much like other regions that depend on tourism as their main industry . Northern Lower Michigan is distinct from the more northerly Upper Peninsula and Isle Royale , which , obviously , are also located in `` northern '' Michigan . In the northern-most 21 counties in the Lower Peninsula of Michigan , the total population of the region is 506,658 people.The largest city is Traverse City . The 4 counties surrounding it make up Traverse City Micropolitan Area and have a population of 143,372 , 7th in nation . |
On_the_Origin_of_Species | On the Origin of Species ( or more completely , On the Origin of Species by Means of Natural Selection , or the Preservation of Favoured Races in the Struggle for Life ) , published on 24 November 1859 , is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology . Darwin 's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection . It presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution . Darwin included evidence that he had gathered on the Beagle expedition in the 1830s and his subsequent findings from research , correspondence , and experimentation . Various evolutionary ideas had already been proposed to explain new findings in biology . There was growing support for such ideas among dissident anatomists and the general public , but during the first half of the 19th century the English scientific establishment was closely tied to the Church of England , while science was part of natural theology . Ideas about the transmutation of species were controversial as they conflicted with the beliefs that species were unchanging parts of a designed hierarchy and that humans were unique , unrelated to other animals . The political and theological implications were intensely debated , but transmutation was not accepted by the scientific mainstream . The book was written for non-specialist readers and attracted widespread interest upon its publication . As Darwin was an eminent scientist , his findings were taken seriously and the evidence he presented generated scientific , philosophical , and religious discussion . The debate over the book contributed to the campaign by T. H. Huxley and his fellow members of the X Club to secularise science by promoting scientific naturalism . Within two decades there was widespread scientific agreement that evolution , with a branching pattern of common descent , had occurred , but scientists were slow to give natural selection the significance that Darwin thought appropriate . During `` the eclipse of Darwinism '' from the 1880s to the 1930s , various other mechanisms of evolution were given more credit . With the development of the modern evolutionary synthesis in the 1930s and 1940s , Darwin 's concept of evolutionary adaptation through natural selection became central to modern evolutionary theory , and it has now become the unifying concept of the life sciences . |
Nuclear_power | Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat , which most frequently is then used in steam turbines to produce electricity in a nuclear power plant . The term includes nuclear fission , nuclear decay and nuclear fusion . Presently , the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind , with nuclear decay processes , primarily in the form of geothermal energy , and radioisotope thermoelectric generators , in niche uses making up the rest . Owing , fundamentally , to the delayed critical fission process , Fission-electric power stations are one of the leading low carbon power generation methods of producing electricity , and in terms of total life-cycle greenhouse gas emissions per unit of energy generated , has emission values lower than `` renewable energy '' when the latter is taken as a single energy source . Since all electricity supplying technologies use cement , etc. , during construction , emissions are yet to be brought to zero . A 2014 analysis of the carbon footprint literature by the Intergovernmental Panel on Climate Change ( IPCC ) reported that the embodied total life-cycle emission intensity of fission electricity has a median value of 12 g eq/kWh which is the lowest out of all commercial baseload energy sources , and second lowest out of all commercial electricity technologies known , after wind power which is an Intermittent energy source with embodied greenhouse gas emissions , per unit of energy generated of 11 g eq/kWh . Each result is contrasted with coal and fossil gas at 820 and 490 g eq/kWh . With this translating into , from the beginning of fission-electric power station commercialization in the 1970s , having prevented the emission of about 64 billion tonnes of carbon dioxide equivalent , greenhouse gases that would have otherwise resulted from the burning of fossil fuels in thermal power stations . There is a social debate about nuclear power . Proponents , such as the World Nuclear Association and Environmentalists for Nuclear Energy , contend that nuclear power is a safe , sustainable energy source that reduces carbon emissions . Opponents , such as Greenpeace International and NIRS , contend that nuclear power poses many threats to people and the environment . Far-reaching fission power reactor accidents , or accidents that resulted in medium to long-lived fission product contamination of inhabited areas , have occurred in Generation I and II reactor designs , blueprinted between 1950 and 1980 . These include the Chernobyl disaster which occurred in 1986 , the Fukushima Daiichi nuclear disaster ( 2011 ) , and the more contained Three Mile Island accident ( 1979 ) . There have also been some nuclear submarine accidents . In terms of lives lost per unit of energy generated , analysis has determined that fission-electric reactors have caused fewer fatalities per unit of energy generated than the other major sources of energy generation . Energy production from coal , petroleum , natural gas and hydroelectricity has caused a greater number of fatalities per unit of energy generated due to air pollution and energy accident effects . Four years after the Fukushima-Daiichi accident , there have been no fatalities due to exposure to radiation , and no discernible increased incidence of radiation-related health effects are expected among exposed members of the public and their descendants . The Japan Times estimated 1,600 deaths were the result of evacuation , due to physical and mental stress stemming from long stays at shelters , a lack of initial care as a result of hospitals being disabled by the tsunami , and suicides . In 2015 : Ten new reactors were connected to the grid . Seven reactors were permanently shut down . 441 reactors had a worldwide net capacity of 382,855 megawatts of electricity . 67 new nuclear reactors were under construction . Most of the new activity is in China where there is an urgent need to control pollution from coal plants . In October 2016 , Watts Bar 2 became the first new United States reactor to enter commercial operation since 1996 . |
Nordic_Seas | The Nordic Seas are located north of Iceland and south of Svalbard . They have also been defined as the region located north of the Greenland-Scotland Ridge and south of the Fram Strait-Spitsbergen-Norway intersection . Known to connect the North Pacific and the North Atlantic waters , this region is also known as having some of the densest waters , creating the densest region found in the North Atlantic Deep Water . The deepest waters of the Arctic Ocean are connected to the worlds other oceans through Nordic Seas and Fram Straight . There are three seas within the Nordic Sea : Greenland Sea , Norwegian Sea , and Iceland Sea . The Nordic Seas only make up about 0.75 % of the World 's Oceans . This region is known as having diverse features in such a small topographic area , such as the mid oceanic ridge systems . Some locations have shallow shelves , while others have deep slopes and basins . This region , because of the atmosphere-ocean transfer of energy and gases , has varying seasonal climate . During the winter , sea ice is formed in the western and northern regions of the Nordic Seas , whereas during the summer months , the majority of the region remains free of ice . Several water masses are found interacting in the Nordic Sea . These water masses are present due to subduction , deep convective mixing , surface/frontal mixing , and entrainment of water from low and high latitudes . Interaction from multiple water sources can lead to varying conditions . New primary production is higher in this region , usually exceeding regenerated primary production . New production is higher in regions where water interacts with Atlantic Water , which has nutrient-rich waters . When looking at carbon flux from the atmosphere to the ocean , this region is considered one of the highest in the world 's oceans . This region is also known as being one of the few bodies of water that take up large quantities of carbon dioxide yearly , ranging from 20-85 g C m − 2y − 1 , which is considered high in comparison the carbon dioxide flux in the world 's oceans . The Nordic Seas include the Greenland Sea , the Norwegian Sea , and the Iceland Sea . The Greenland and the Norwegian Sea are separately distinguished by Mohn 's Ridge . The Greenland and Iceland Sea are separated by the Jan Mayen fracture zone , and the Norwegian and Iceland Seas have the Aegir Ridge between them . The Nordic Seas have varying and diverse features as a result of each sea having separate water mass structures and circulation patterns . The Greenland Sea produces dense waters because of its high salinity and cooler temperatures from winter cooling . Higher salinity is present as a result of the Greenland Sea 's close proximity to the salinity inflow that occurs from the Atlantic Ocean . Another dense water source comes from the Arctic waters that also flow into the Greenland Sea . These water source mixtures are important because they play a role in the overflows that occur in the North Atlantic . The water that overflows from the Greenland ridge becomes the North Atlantic Deep Water dense water , even though this body of water does not make up the deep waters of the Nordic Sea . |
Nuclear_power_in_the_United_States | Nuclear power in the United States is provided by 100 commercial reactors with a net summer capacity of 100,350 megawatts ( MW ) , 66 pressurized water reactors and 34 boiling water reactors . In 2015 they produced a total of 797.2 terawatt-hours of electricity , which accounted for 19.50 % of the nation 's total electric energy generation . As of 2016 , there are four new reactors under construction with a gross electrical capacity of 5,000 MW , while 33 reactors have been permanently shut down . The United States is the world 's largest producer of commercial nuclear power , and in 2013 generated 33 % of the world 's nuclear electricity . As of October 2014 , the NRC has granted license renewals providing a 20-year extension to a total of 74 reactors . In early 2014 , the NRC prepared to receive the first applications of license renewal beyond 60 years of reactor life , as early as 2017 , a process which by law requires public involvement . Licenses for 22 reactors are due to expire before the end of the next decade if no renewals are granted . The Vermont Yankee Nuclear Power Plant was the most recent nuclear power plant to be decommissioned on December 29 , 2014 . Another four aging reactors were permanently closed in 2013 before their licenses expired because of high maintenance and repair costs at a time when natural gas prices have fallen : San Onofre 2 and 3 in California , Crystal River 3 in Florida , and Kewaunee in Wisconsin , and New York State is seeking to close Indian Point in Buchanan , 30 miles from New York City . Most reactors began construction by 1974 ; following the Three Mile Island accident in 1979 and changing economics , many planned projects were canceled . More than 100 orders for nuclear power reactors , many already under construction , were canceled in the 1970s and 1980s , bankrupting some companies . Up until 2013 , there had also been no ground-breaking on new nuclear reactors at existing power plants since 1977 . Then in 2012 , the NRC approved construction of four new reactors at existing nuclear plants . Construction of the Virgil C. Summer Nuclear Generating Station Units 2 and 3 began on March 9 , 2013 . A few days later , on March 12 , construction began on the Vogtle Electric Generating Plant Units 3 and 4 . In addition , on October 19 , 2016 TVA 's Unit-2 reactor at the Watts Bar Nuclear Generating Station became the first US reactor to enter commercial operation since 1996 . There was a revival of interest in nuclear power in the 2000s , with talk of a `` nuclear renaissance '' , supported particularly by the Nuclear Power 2010 Program . A number of applications were made , but facing economic challenges , and later in the wake of the Fukushima Daiichi nuclear disaster , most of these projects have been cancelled , and , `` nuclear industry officials say they expect five new reactors to enter service by 2020 -- Southern 's two Vogtle reactors , two at Summer in South Carolina and one at Watts Bar in Tennessee '' ; these are all at existing plants . As of August 2013 , there are construction delays at Vogtle and Summer . |
Oligotroph | An oligotroph is an organism that can live in an environment that offers very low levels of nutrients . They may be contrasted with copiotrophs , which prefer nutritionally rich environments . Oligotrophs are characterized by slow growth , low rates of metabolism , and generally low population density . The adjective oligotrophic may be used to refer to environments that offer little to sustain life , organisms that survive in such environments , or the adaptations that support survival . Etymologically , the word `` oligotroph '' is a combination of the Greek adjective oligos meaning `` few '' and the adjective trophikos meaning `` feeding '' . Oligotrophic environments include deep oceanic sediments , caves , glacial and polar ice , deep subsurface soil , aquifers , ocean waters , and leached soils . Examples of oligotrophic organisms are the cave-dwelling olm ; the bacterium , Pelagibacter ubique , which is the most abundant organism in the oceans with an estimated 2 × 1028 individuals in total ; and the lichens with their extremely low metabolic rate . |
North_Atlantic_oscillation | The North Atlantic Oscillation ( NAO ) is a weather phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level ( SLP ) between the Icelandic low and the Azores high . Through fluctuations in the strength of the Icelandic low and the Azores high , it controls the strength and direction of westerly winds and location of storm tracks across the North Atlantic . It is part of the Arctic oscillation , and varies over time with no particular periodicity . The NAO was discovered through several studies in the late 19th and early 20th centuries . Unlike the El Niño-Southern Oscillation phenomenon in the Pacific Ocean , the NAO is a largely atmospheric mode . It is one of the most important manifestations of climate fluctuations in the North Atlantic and surrounding humid climates . The North Atlantic Oscillation is closely related to the Arctic oscillation ( AO ) or Northern Annular Mode ( NAM ) , but should not be confused with the Atlantic Multidecadal Oscillation ( AMO ) . |
Oil_spill | An oil spill is the release of a liquid petroleum hydrocarbon into the environment , especially marine areas , due to human activity , and is a form of pollution . The term is usually applied to marine oil spills , where oil is released into the ocean or coastal waters , but spills may also occur on land . Oil spills may be due to releases of crude oil from tankers , offshore platforms , drilling rigs and wells , as well as spills of refined petroleum products ( such as gasoline , diesel ) and their by-products , heavier fuels used by large ships such as bunker fuel , or the spill of any oily refuse or waste oil . Oil spills penetrate into the structure of the plumage of birds and the fur of mammals , reducing its insulating ability , and making them more vulnerable to temperature fluctuations and much less buoyant in the water . Cleanup and recovery from an oil spill is difficult and depends upon many factors , including the type of oil spilled , the temperature of the water ( affecting evaporation and biodegradation ) , and the types of shorelines and beaches involved . Spills may take weeks , months or even years to clean up . Oil spills can have disastrous consequences for society ; economically , environmentally , and socially . As a result , oil spill accidents have initiated intense media attention and political uproar , bringing many together in a political struggle concerning government response to oil spills and what actions can best prevent them from happening . |
North_Pole | The North Pole , also known as the Geographic North Pole or Terrestrial North Pole , is ( subject to the caveats explained below ) defined as the point in the Northern Hemisphere where the Earth 's axis of rotation meets its surface . The North Pole is the northernmost point on the Earth , lying diametrically opposite the South Pole . It defines geodetic latitude 90 ° North , as well as the direction of true north . At the North Pole all directions point south ; all lines of longitude converge there , so its longitude can be defined as any degree value . Along tight latitude circles , counterclockwise is east and clockwise is west . The North Pole is at the center of the Northern Hemisphere . While the South Pole lies on a continental land mass , the North Pole is located in the middle of the Arctic Ocean amid waters that are almost permanently covered with constantly shifting sea ice . This makes it impractical to construct a permanent station at the North Pole ( unlike the South Pole ) . However , the Soviet Union , and later Russia , constructed a number of manned drifting stations on a generally annual basis since 1937 , some of which have passed over or very close to the Pole . Since 2002 , the Russians have also annually established a base , Barneo , close to the Pole . This operates for a few weeks during early spring . Studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage , with timescales varying from 2016 to the late 21st century or later . The sea depth at the North Pole has been measured at 4261 m by the Russian Mir submersible in 2007 and at 4,087 m ( 13,410 ft ) by USS Nautilus in 1958 . The nearest land is usually said to be Kaffeklubben Island , off the northern coast of Greenland about 700 km away , though some perhaps non-permanent gravel banks lie slightly closer . The nearest permanently inhabited place is Alert in the Qikiqtaaluk Region , Nunavut , Canada , which is located 817 km from the Pole . |
Northern_Europe | Northern Europe is the northern part or region of Europe . Although no definitive borders or definition exists for the term , geographically , Northern Europe may be considered to consist approximately of all of Europe above the 52nd parallel north ; which includes ( from west to east ) most or all of : Iceland , the Republic of Ireland , the Isle of Man , the United Kingdom , the Faroe Islands , the Netherlands , northern Germany , Denmark , Norway , Sweden , Finland , Estonia , Latvia , Lithuania , Belarus and northwest Russia . However , narrower definitions may also be used based on other geographical factors , such as climate and ecology . Greenland , geographically a part of North America , is politically a part of the Kingdom of Denmark , and may be included depending on the definition . While Northern Europe overlaps with most of Northwestern Europe and Northeastern Europe , it does not border Southern Europe . Countries which are central-western ( such as Belgium ) , central-central ( such as Austria ) , or central-eastern ( such as Poland ) are generally considered part of neither Northern nor Southern Europe . Notable geographical features of Northern Europe include the North European Plain in the mid-north of Europe , the Fennoscandian Peninsula in the far-north , Baltic plain , and the British Isles in the northwest |
North_American_Arctic | The North American Arctic comprises the northern portions of Alaska ( USA ) , Northern Canada and Greenland . Major bodies of water include the Arctic Ocean , Hudson Bay , the Gulf of Alaska and North Atlantic Ocean . The western limit is the Seward Peninsula and the Bering Strait . The southern limit is the Arctic Circle latitude of 66 ° 33 'N , which is the approximate limit of the midnight sun and the polar night . The region is defined by environmental limits where the average temperature for the warmest month ( July ) is below 10 C . The northernmost tree line roughly follows the isotherm at the boundary of this region . The area has tundra and polar vegetation . |
North_America | North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere . It can also be considered a northern subcontinent of the Americas . It is bordered to the north by the Arctic Ocean , to the east by the Atlantic Ocean , to the west and south by the Pacific Ocean , and to the southeast by South America and the Caribbean Sea . North America covers an area of about 24,709,000 square kilometers ( 9,540,000 square miles ) , about 16.5 % of the earth 's land area and about 4.8 % of its total surface . North America is the third largest continent by area , following Asia and Africa , and the fourth by population after Asia , Africa , and Europe . In 2013 , its population was estimated at nearly 565 million people in 23 independent states , or about 7.5 % of the world 's population , if nearby islands ( most notably the Caribbean ) are included . North America was reached by its first human populations during the last glacial period , via crossing the Bering land bridge approximately 40,000 to 17,000 years ago . The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago ( the beginning of the Archaic or Meso-Indian period ) . The Classic stage spans roughly the 6th to 13th centuries . The Pre-Columbian era ended with the transatlantic migrations and the arrival of European settlers during the Age of Discovery and the Early Modern period . Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists , indigenous peoples , African slaves and their descendants . European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south . Because of the history of colonialism , most North Americans speak English , Spanish or French and societies and states commonly reflect Western traditions . |
Nuclear_winter | Nuclear winter is the severe global-climatic-cooling-effect , hypothesized to occur after the ignition of a number of firestorms , from nuclear bomb detonations , or wide spread bombardments . Such fires , which can inject soot into the stratosphere , have historically occurred in a number of cities , with nuclear winter researchers using both Hamburg and the less ferocious Hiroshima firestorms as the principal examples . However , as firestorms are most frequently encountered in much larger area wildfires , these latter fires are the most significant today in assessing both the initial and present-day `` nuclear winter '' computer models . |
Nonfarm_payrolls | Nonfarm payroll employment is a compiled name for goods , construction and manufacturing companies in the US . It does not include farm workers , private household employees , or non-profit organization employees . It is an influential statistic and economic indicator released monthly by the United States Department of Labor as part of a comprehensive report on the state of the labor market . The financial assets most affected by the NFP data include the US dollar , equities and gold . The markets react very quickly and most of the time in a very volatile fashion around the time the NFP data is released . The short-term market moves indicate that there is a very strong correlation between the NFP data and the strength of the US dollar . Historical price movement data shows a small negative correlation between the NFP data and the US dollar Index . The Bureau of Labor Statistics releases preliminary data on the third Friday after the conclusion of the reference week , i.e. , the week which includes the 12th of the month , at 8:30 a.m. Eastern Time ; typically this date occurs on the first Friday of the month . Nonfarm payroll is included in the monthly Employment Situation or informally the jobs report and affects the US dollar , the Foreign exchange market , the bond market , and the stock market . The figure released is the change in nonfarm payrolls ( NFP ) , compared to the previous month , and is usually between +10,000 and +250,000 during non-recessional times . The NFP number is meant to represent the number of jobs added or lost in the economy over the last month , not including jobs relating to the farming industry . |
Ocean_surface_topography | The ocean surface has highs and lows , similar to the hills and valleys of Earth 's land surface depicted on a topographic map . These variations , called ocean surface topography ( or sea surface topography ) , also dynamic topography , are mapped using direct ( usually satellite-based ) or indirect measurements of sea surface height relative to Earth 's geoid . Earth 's geoid is a calculated surface of equal gravitational potential energy and represents the shape the sea surface would be if the ocean were not in motion . The main purpose of measuring ocean surface topography is to understand the large-scale circulation of the ocean . On a daily basis , SSH is most obviously affected by the tidal forces of the Moon and the Sun acting on the Earth . Over longer timescales , SSH is influenced by ocean circulation . Typically , SSH anomalies resulting from these forces differ from the mean by less than ± 1 m at the global scale . Other influences include temperature , salinity , tides , waves , and the loading of atmospheric pressure . The slowest and largest variations are due to changes in the Earth 's gravitational field ( geoid ) due to the rearrangement of continents , formation of sea mounts and other redistribution of rock . Since the Earth 's gravitational field is relatively stable on decadal to centennial timescales , ocean circulation plays a more significant role in the observed variation of SSH . Across the seasonal cycle changes in patterns of warming , cooling and surface wind forcing affect circulation and influence SSH . Variations in SSH can be measured by satellite altimetry ( e.g. TOPEX/Poseidon ) and used to calculate determine sea level rise and properties such as ocean heat storage . |
Oligocene | The Oligocene ( -LSB- pronˈɒlᵻɡoʊsiːn -RSB- ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ) . As with other older geologic periods , the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain . The name Oligocene comes from the Ancient Greek ὀλίγος ( oligos , `` few '' ) and καινός ( kainos , `` new '' ) , and refers to the sparsity of extant forms of molluscs . The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch . The Oligocene is the third and final epoch of the Paleogene Period . The Oligocene is often considered an important time of transition , a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene . Major changes during the Oligocene included a global expansion of grasslands , and a regression of tropical broad leaf forests to the equatorial belt . The start of the Oligocene is marked by a notable extinction event called the Grande Coupure ; it featured the replacement of European fauna with Asian fauna , except for the endemic rodent and marsupial families . By contrast , the Oligocene -- Miocene boundary is not set at an easily identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the relatively cooler Miocene . |
Novaya_Zemlya | Novaya Zemlya ( -LSB- Но́вая Земля́ , p = ˈnovəjə zʲɪmˈlʲa -RSB- , lit . new land ) , also known , especially in Dutch , as Nova Zembla , is an archipelago in the Arctic Ocean in northern Russia and the extreme northeast of Europe , the easternmost point of Europe lying at Cape Flissingsky on the Northern island . Administratively , it is incorporated as Novaya Zemlya District , one of the twenty-one in Arkhangelsk Oblast , Russia . Municipally , it is incorporated as Novaya Zemlya Urban Okrug . Its population as of the 2010 Census was 2,429 , of which 1,972 resided in Belushya Guba , an urban-type settlement that is the administrative center of Novaya Zemlya District . The population in 2002 was The indigenous population ( from 1872 to the 1950s when it was resettled to the mainland ) consisted of about 50 -- 300 Nenetses who subsisted mainly on fishing , trapping , reindeer herding , polar bear hunting and seal hunting . Natural resources include copper , lead , and zinc . Novaya Zemlya was a sensitive military area during the Cold War years and it is still used today . The Soviet Air Force maintained a presence at Rogachevo on the southern part of the island , on the westernmost peninsula . It was used primarily for interceptor aircraft operations but also provided logistical support for the nearby nuclear test area . Novaya Zemlya was the site of one of the two major nuclear test sites managed by the USSR , used for air drops and underground testing the largest of the Soviet nuclear bombs , in particular the October 30 , 1961 air burst explosion of Tsar Bomba , the largest , most powerful nuclear weapon ever detonated . |
North_Africa | North Africa is the term given to a group of Mediterranean countries situated in the northern-most region of the African continent . The term `` North Africa '' has no single accepted definition . It is sometimes defined as stretching from the Atlantic shores of Morocco in the west , to the Suez Canal and the Red Sea in the east . Others have limited it to the countries of Morocco , Algeria , and Tunisia , a region known by the French during colonial times as `` Afrique du Nord '' and by the Arabs as the Maghreb ( `` West '' ) . The most commonly accepted definition includes Morocco , Algeria , and Tunisia , as well as Libya and Egypt , It should be noted however that the term `` North Africa '' , when commonly used in North Africa and the Middle East , often refers only to the countries of the Maghreb and Libya . Egypt , due to its greater Middle Eastern associations , is typically viewed separately . The countries of North Africa share a common ethnic , cultural and linguistic identity that is unique to this region . North west Africa has been inhabited by Berbers since the beginning of recorded history , while the eastern part of North Africa has been home to the Egyptians . Following the Muslim conquest in the seventh century C.E. , the region underwent a process of Arabization and Islamization that has defined its cultural landscape ever since . The distinction between North Africa and much of Sub-Saharan Africa is historically and ecologically significant because of the effective barrier created by the Sahara Desert for much of modern history . From 3500 BC , following the abrupt desertification of the Sahara due to gradual changes in the Earth 's orbit , this barrier has culturally separated the North from the rest of the continent . As the seafaring civilizations of the Phoenicians , Greeks , Romans , Muslims and others facilitated communication and migration across the Mediterranean Sea , the cultures of North Africa became much more closely tied to Southwestern Asia and Europe than Sub-Saharan Africa . The Islamic influence in the area is also significant , and North Africa is a major part of the Muslim world . Some researchers have postulated that North Africa rather than East Africa served as the exit point for the modern humans who first trekked out of the continent in the Out of Africa migration . |
Olympic_marmot | The Olympic marmot ( Marmota olympus ) is a rodent in the squirrel family , Sciuridae ; it occurs only in the U.S. state of Washington , on the middle elevations of the Olympic Peninsula . The closest relatives of this species are the hoary marmot and the Vancouver Island marmot . In 2009 , it was declared the official endemic mammal of Washington . This marmot is about the size of a domestic cat , typically weighing about 8 kg in summer . The species shows the greatest sexual dimorphism found in marmots , with adult males weighing on average 23 % more than females . It can be identified by a wide head , small eyes and ears , stubby legs , and a long , bushy tail . Its sharp , rounded claws aid in digging burrows . The coat color changes with the season and with age , but an adult marmot 's coat is brown all over with small whiter areas for most of the year . The species has a diet consisting mainly of a variety of meadow flora , including dry grasses , which it also uses as bedding in burrows . It is preyed on by various terrestrial mammals and avian raptors , but its main predator today is the coyote . The Olympic marmot is rated a species of the least concern on the IUCN Red List . It is protected by law in the Olympic National Park , which contains most of its habitat . The burrows of this marmot are made in colonies , which are found in various mountain locations and differ in size . A colony may contain as few as one marmot family or multiple families with up to 40 marmots . Olympic marmots are very sociable animals which often engage in play fighting and vocalize four different whistles to communicate . During hibernation beginning in September , they are in a deep sleep and do not eat , causing them to lose half their body mass . Adults emerge in May and their young in June . Female marmots reach sexual maturity at three years of age , and produce litters of 1 -- 6 every other mating season . |
Ocean | An ocean ( , the sea of classical antiquity ) is a body of saline water that composes much of a planet 's hydrosphere . On Earth , an ocean is one of the major conventional divisions of the World Ocean , which covers almost 71 % of its surface . These are , in descending order by area , the Pacific , Atlantic , Indian , Southern ( Antarctic ) , and Arctic Oceans . The word sea is often used interchangeably with `` ocean '' in American English but , strictly speaking , a sea is a body of saline water ( generally a division of the world ocean ) partly or fully enclosed by land . Saline water covers approximately 72 % of the planet 's surface ( ~ 3.6 km2 ) and is customarily divided into several principal oceans and smaller seas , with the ocean covering approximately 71 % of Earth 's surface and 90 % of the Earth 's biosphere . The ocean contains 97 % of Earth 's water , and oceanographers have stated that less than 5 % of the World Ocean has been explored . The total volume is approximately 1.35 billion cubic kilometers ( 320 million cu mi ) with an average depth of nearly 3700 m. As the world ocean is the principal component of Earth 's hydrosphere , it is integral to all known life , forms part of the carbon cycle , and influences climate and weather patterns . The world ocean is the habitat of 230,000 known species , but because much of it is unexplored , the number of species that exist is much larger , possibly over two million . The origin of Earth 's oceans remains unknown ; oceans are thought to have formed in the Hadean period and may have been the impetus for the emergence of life . Extraterrestrial oceans may be composed of water or other elements and compounds . The only confirmed large stable bodies of extraterrestrial surface liquids are the lakes of Titan , although there is evidence for the existence of oceans elsewhere in the Solar System . Early in their geologic histories , Mars and Venus are theorized to have had large water oceans . The Mars ocean hypothesis suggests that nearly a third of the surface of Mars was once covered by water , and a runaway greenhouse effect may have boiled away the global ocean of Venus . Compounds such as salts and ammonia dissolved in water lower its freezing point so that water might exist in large quantities in extraterrestrial environments as brine or convecting ice . Unconfirmed oceans are speculated beneath the surface of many dwarf planets and natural satellites ; notably , the ocean of Europa is estimated to have over twice the water volume of Earth . The Solar System 's giant planets are also thought to have liquid atmospheric layers of yet to be confirmed compositions . Oceans may also exist on exoplanets and exomoons , including surface oceans of liquid water within a circumstellar habitable zone . Ocean planets are a hypothetical type of planet with a surface completely covered with liquid . |
Nonpoint_source_water_pollution_regulations_in_the_United_States | Nonpoint source ( NPS ) water pollution regulations are environmental regulations that restrict or limit water pollution from diffuse or nonpoint effluent sources such as polluted runoff from agricultural areas in a river catchments or wind-borne debris blowing out to sea . In the United States , governments have taken a number of legal and regulatory approaches to controlling NPS effluent . Nonpoint water pollution sources include , for example , leakage from underground storage tanks , storm water runoff , atmospheric deposition of contaminants , and golf course , agricultural , and forestry runoff . Nonpoint sources are the most significant single source of water pollution in the United States , accounting for almost half of all water pollution , and agricultural runoff is the single largest source of nonpoint source water pollution . This water pollution has a number of detrimental effects on human health and the environment . Unlike point source pollution , nonpoint source pollution arises from numerous and diverse sources , making identification , monitoring , and regulation more complex . |
Oil_shale_industry | The oil shale industry is an industry of mining and processing of oil shale -- a fine-grained sedimentary rock , containing significant amounts of kerogen ( a solid mixture of organic chemical compounds ) , from which liquid hydrocarbons can be manufactured . The industry has developed in Brazil , China , Estonia and to some extent in Germany and Russia . Several other countries are currently conducting research on their oil shale reserves and production methods to improve efficiency and recovery . However , Australia has halted their pilot projects due to environmental concerns . Estonia accounted for about 70 % of the world 's oil shale production in a study published in 2005 . Oil shale has been used for industrial purposes since the early 17th century , when it was mined for its minerals . Since the late 19th century , shale oil has also been used for its oil content and as a low grade fuel for power generation . However , barring countries having significant oil shale deposits , its use for power generation is not particularly widespread . Similarly , oil shale is a source for production of synthetic crude oil and it is seen as a solution towards increasing domestic production of oil in countries that are reliant on imports . |
Nuclear_holocaust | A nuclear holocaust or nuclear apocalypse is a theoretical scenario involving widespread destruction and radioactive fallout causing the collapse of civilization , through the use of nuclear weapons . Under such a scenario , some of the Earth is made uninhabitable by nuclear warfare in future world wars . Besides the obvious direct destruction of cities by nuclear blasts , the potential aftermath of a nuclear war could involve firestorms , a nuclear winter , widespread radiation sickness from fallout , and/or the temporary loss of much modern technology due to electromagnetic pulses . Some scientists , such as Alan Robock , have speculated that a thermonuclear war could result in the end of modern civilization on Earth , in part due to a long-lasting nuclear winter . In one model , temperatures following a full thermonuclear war fall for several years by 7 to 8 degrees Celsius on average . The accuracy of such models are often the subject of partisan dispute . Early Cold War-era studies suggested that billions of humans would nonetheless survive the immediate effects of nuclear blasts and radiation following a global thermonuclear war . Some scholars argue that nuclear war could indirectly contribute to human extinction via secondary effects , including environmental consequences , societal breakdown , and economic collapse . Additionally , it has been argued that even a relatively small-scale nuclear exchange between India and Pakistan involving 100 Hiroshima yield weapons , could cause a nuclear winter and kill more than a billion people . Since 1947 , the Doomsday Clock of the Bulletin of the Atomic Scientists has visualized how close the world is from a nuclear war . The threat of a nuclear holocaust plays an important role in the popular perception of nuclear weapons . It features in the security concept of mutually assured destruction ( MAD ) and is a common scenario in survivalism . Nuclear holocaust is a common feature in literature and film , especially in speculative genres such as science fiction , dystopian and post-apocalyptic fiction . |
North_Atlantic_Deep_Water | North Atlantic Deep Water ( NADW ) is a deep water mass formed in the North Atlantic Ocean . Thermohaline circulation of the world 's oceans involves the flow of warm surface waters from the southern hemisphere into the North Atlantic . Water flowing northward becomes modified through evaporation and mixing with other water masses , leading to increased salinity . When this water reaches the North Atlantic it cools and sinks through convection , due to its decreased temperature and increased salinity resulting in increased density . NADW is the outflow of this thick deep layer , which can be detected by its high salinity , high oxygen content , nutrient minima , and chlorofluorocarbons ( CFCs ) . CFCs are anthropogenic substances that enter the surface of the ocean from gas exchange with the atmosphere . This distinct composition allows its path to be traced as it mixes with Circumpolar Deep Water ( CDW ) , which in turn fills the deep Indian Ocean and part of the South Pacific . NADW and its formation is essential to the Atlantic Meridional Overturning Circulation ( AMOC ) , which is responsible for transporting large amounts of water , heat , salt , carbon , nutrients and other substances from the Tropical Atlantic to the Mid and High Latitude Atlantic . In the conveyor belt model of thermohaline circulation of the world 's oceans , the sinking of NADW pulls the waters of the North Atlantic drift northward ; however , this is almost certainly an oversimplification of the actual relationship between NADW formation and the strength of the Gulf Stream/North Atlantic drift . NADW has a temperature of 2-4 ° C with a salinity of 34.9-35 .0 psu found at a depth between 1500 and 4000m . |
Opinion | In general , an opinion is a judgment , viewpoint , or statement that is not conclusive . It may deal with subjective matters in which there is no conclusive finding . What distinguishes fact from opinion is that facts are more likely to be verifiable , i.e. can be agreed to by the consensus of experts . An example is : `` United States of America was involved in the Vietnam War '' versus `` United States of America was right to get involved in the Vietnam War '' . An opinion may be supported by facts and principles , in which case it becomes an argument . Different people may draw opposing conclusions ( opinions ) even if they agree on the same set of facts . Opinions rarely change without new arguments being presented . It can be reasoned that one opinion is better supported by the facts than another by analyzing the supporting arguments . In casual use , the term opinion may be the result of a person 's perspective , understanding , particular feelings , beliefs , and desires . It may refer to unsubstantiated information , in contrast to knowledge and fact . Collective or professional opinions are defined as meeting a higher standard to substantiate the opinion . ( see below ) |
Nuclear_power_proposed_as_renewable_energy | Although nuclear power is considered a form of low-carbon power , its legal inclusion with renewable energy power sources has been a subject of debate and classification . Statutory definitions of renewable energy usually exclude many present nuclear energy technologies , with notable exceptions in the states of Utah , and Arizona in the United States , where only a particular implementation of nuclear fission with `` waste '' / fuel recycling meets the state 's criteria . Dictionary sourced definitions of renewable energy technologies often omit or explicitly exclude mention to every nuclear energy source , with an exception made for the natural nuclear decay heat generated within the Earth/geothermal energy . The most common fuel used in conventional nuclear fission power stations , uranium-235 is `` non-renewable '' according to the Energy Information Administration , the organization however is silent on the recycled fuel of MOX . Similarly , the National Renewable Energy Laboratory does not mention nuclear power in its `` energy basics '' definition . In 1987 , the World Commission on Environment and Development ( WCED ) classified fission reactors that produce more fissile nuclear fuel than they consume ( breeder reactors , and if developed , fusion power ) among conventional renewable energy sources , such as solar and falling water . The American Petroleum Institute likewise does not consider conventional nuclear fission as renewable , but that breeder reactor nuclear fuel is considered renewable and sustainable , and while conventional fission leads to waste streams that remain a concern for millennia , the waste from efficiently burnt up spent fuel requires storage for no more than a thousand years . The monitoring and storage of radioactive waste products is also required upon the use of other renewable energy sources , such as geothermal energy . |
North_Atlantic_Current | The North Atlantic Current ( NAC ) , also known as North Atlantic Drift and North Atlantic Sea Movement , is a powerful warm western boundary current that extends the Gulf Stream north-eastward . The NAC originates from where the Gulf Stream turns north at the Southeast Newfoundland Rise , a submarine ridge that stretches south-east from the Grand Banks . The NAC flows northward east of the Grand Banks , from 40 ° N to 51 ° N , before turning sharply east to cross the Atlantic . It transports more warm tropical water to northern latitudes than any other boundary current ; more than 40 Sv in the south and 20 Sv as it crosses the Mid-Atlantic Ridge . It reaches speeds of 2 knots near the North American coast . Directed by topography , the NAC meanders heavily but , in contrast to the meanders of the Gulf Stream , the NAC meanders remain stable without breaking off into eddies . The colder parts of the Gulf Stream turn northward near the `` tail '' of the Grand Banks at 50 ° W where the Azores Current branches off to flow south of the Azores . From there the NAC flow north-eastward east of the Flemish Cap ( 47 ° N , 45 ° W ) . Approaching the Mid-Atlantic Ridge , it then turns eastward and becomes much broader and more diffuse . It then splits into a colder , north-eastern branch and a warmer eastern branch . As the warmer branch turns southward most of the subtropical component of the Gulf Stream has been diverted southward and , as a consequence , the North Atlantic is mostly supplied by subpolar waters , including a contribution from the Labrador Current recirculated into the NAC at 45 ° N. West of Continental Europe , it splits into two major branches . One branch goes southeast , later to become the Canary Current as it passes northwest Africa and turns southwest . The other major branch continues north along the coast of Northwestern Europe . Other branches include the Irminger Current and the Norwegian Current . Driven by the global thermohaline circulation ( THC ) , the North Atlantic Current is part of the wind-driven Gulf Stream , which goes further east and north from the North American coast across the Atlantic and into the Arctic Ocean . The North Atlantic Current , together with the Gulf Stream , have a long-lived reputation for having a considerable warming influence on European climate . The principal cause for differences in winter climate between North America and Europe is , however , winds rather than ocean currents . |
Optimal_decision | An optimal decision is a decision that leads to at least as good an outcome as all other available decision options . It is an important concept in decision theory . In order to compare the different decision outcomes , one commonly assigns a relative utility to each of them . If there is uncertainty as to what the outcome will be , then under the von Neumann -- Morgenstern axioms the optimal decision maximizes the expected utility ( utility averaged over all possible outcomes of a decision ) . Sometimes , the equivalent problem of minimizing loss is considered , particularly in financial situations , where the utility is defined as economic gain . `` Utility '' is only an arbitrary term for quantifying the desirability of a particular decision outcome and not necessarily related to `` usefulness . '' For example , it may well be the optimal decision for someone to buy a sports car rather than a station wagon , if the outcome in terms of another criterion ( e.g. , effect on personal image ) is more desirable , even given the higher cost and lack of versatility of the sports car . The problem of finding the optimal decision is a mathematical optimization problem . In practice , few people verify that their decisions are optimal , but instead use heuristics to make decisions that are `` good enough '' -- that is , they engage in satisficing . A more formal approach may be used when the decision is important enough to motivate the time it takes to analyze it , or when it is too complex to solve with more simple intuitive approaches , such as with a large number of available decision options and a complex decision -- outcome relationship . |
Nuclear_force | The nuclear force ( or nucleon -- nucleon interaction or residual strong force ) is a force that acts between the protons and neutrons of atoms . Neutrons and protons , both nucleons , are affected by the nuclear force almost identically . Since protons have charge +1 e , they experience an electric force that tends to push them apart , but at short range the attractive nuclear force is strong enough to overcome the electromagnetic force . The nuclear force binds nucleons into atomic nuclei . The nuclear force is powerfully attraction between nucleons at distances of about 1 femtometre ( fm , or 1.0 × 10 − 15 metres ) , but it rapidly decreases to insignificance at distances beyond about 2.5 fm . At distances less than 0.7 fm , the nuclear force becomes repulsion . This repulsive component is responsible for the physical size of nuclei , since the nucleons can come no closer than the force allows . By comparison , the size of an atom , measured in angstroms ( Å , or 1.0 × 10 − 10 m ) , is five orders of magnitude larger . The nuclear force is not simple , however , since it depends on the nucleon spins , has a tensor component , and may depend on the relative momentum of the nucleons . The nuclear force is not one of the fundamental forces of nature . The nuclear force plays an essential role in storing energy that is used in nuclear power and nuclear weapons . Work ( energy ) is required to bring charged protons together against their electric repulsion . This energy is stored when the protons and neutrons are bound together by the nuclear force to form a nucleus . The mass of a nucleus is less than the sum total of the individual masses of the protons and neutrons . The difference in masses is known as the mass defect , which can be expressed as an energy equivalent . Energy is released when a heavy nucleus breaks apart into two or more lighter nuclei . This energy is the electromagnetic potential energy that is released when the nuclear force no longer holds the charged nuclear fragments together . A quantitative description of the nuclear force relies on equations that are partly empirical . These equations model the internucleon potential energies , or potentials . ( Generally , forces within a system of particles can be more simply modeled by describing the system 's potential energy ; the negative gradient of a potential is equal to the vector force . ) The constants for the equations are phenomenological , that is , determined by fitting the equations to experimental data . The internucleon potentials attempt to describe the properties of nucleon -- nucleon interaction . Once determined , any given potential can be used in , e.g. , the Schrödinger equation to determine the quantum mechanical properties of the nucleon system . The discovery of the neutron in 1932 revealed that atomic nuclei were made of protons and neutrons , held together by an attractive force . By 1935 the nuclear force was conceived to be transmitted by particles called mesons . This theoretical development included a description of the Yukawa potential , an early example of a nuclear potential . Mesons , predicted by theory , were discovered experimentally in 1947 . By the 1970s , the quark model had been developed , by which the mesons and nucleons were viewed as composed of quarks and gluons . By this new model , the nuclear force , resulting from the exchange of mesons between neighboring nucleons , is a residual effect of the strong force . |
Nostradamus_Effect | Nostradamus Effect is an American sensationalist television series that premiered on September 9 , 2009 , on the History channel . The program detailed various historical apocalyptic prophecies , such as the 2012 phenomenon . The show was named after reputed French seer Michel de Nostredame , more commonly known as Nostradamus . Season 1 ended ; the series was not renewed for a season 2 . It presented itself in a `` documentary style '' but it was not a documentary . The show 's disclaimer stated that it does not to take sides regarding the apocalyptic prophecies . In the introduction of each episode , the narrator states , `` We will neither refute , nor endorse , these theories ; merely , present the evidence . '' Despite this claim , prophecies are often exaggerated or presented incorrectly . For example , the show repeatedly claims that the Mayan Long Count calendar predicts the end of the world for December 21 , 2012 while in reality it marks the first day of the 14th b ` ak ` tun era and not any belief in the end of the world . The series was described as full of misleading suggestions supported by vague , unattributed weasel phrases such as `` some think that '' , `` many believe that '' , and `` scholars suggest that '' , while in his book 2012 : It 's Not the End of the World Nostradamus specialist Peter Lemesurier describes its Nostradamian aspects as ` largely fiction ' and lurid nonsense ' . |
Not_even_wrong | The phrase `` not even wrong '' describes any argument that purports to be scientific but fails at some fundamental level , usually in that it contains a terminal logical fallacy or it can not be falsified by experiment ( i.e. , tested with the possibility of being rejected ) , or can not be used to make predictions about the natural world . The phrase is generally attributed to theoretical physicist Wolfgang Pauli , who was known for his colorful objections to incorrect or sloppy thinking . Rudolf Peierls documents an instance in which `` a friend showed Pauli the paper of a young physicist which he suspected was not of great value but on which he wanted Pauli 's views . Pauli remarked sadly , ` It is not even wrong ' . '' This is also often quoted as `` That is not only not right ; it is not even wrong , '' or `` Das ist nicht nur nicht richtig ; es ist nicht einmal falsch ! '' in Pauli 's native German . Peierls remarks that quite a few apocryphal stories of this kind have been circulated and mentions that he listed only the ones personally vouched for by him . He also quotes another example when Pauli replied to Lev Landau , `` What you said was so confused that one could not tell whether it was nonsense or not . '' The phrase is often used to describe pseudoscience or bad science and is considered derogatory . |
Oceanic_climate | An oceanic climate ( also known as marine , west coast and maritime ) is the Köppen classification of the climate typical of west coasts in higher middle latitudes of continents , and generally features cool summers ( relative to their latitude ) and cool but not cold winters , with a relatively narrow annual temperature range and few extremes of temperature , with the exception for transitional areas to continental , subarctic and highland climates . Oceanic climates are defined as having a monthly mean temperature below 22 C in the warmest month , and above 0 C in the coldest month . It typically lacks a dry season , as precipitation is more evenly dispersed throughout the year . It is the predominant climate type across much of North Western Europe , the Pacific Northwest region of the United States and Canada , portions of southwestern South America and small areas of southeast Australia , and New Zealand as well as isolated locations elsewhere . Oceanic climates generally have cool summers and cool ( but not cold ) winters . They are characterised by a narrower annual range of temperatures than are encountered in other places at a comparable latitude , and generally do not have the extremely dry summers of Mediterranean climates or the hot summers of humid subtropical . Oceanic climates are most dominant in Europe , where they spread much farther inland than in other continents . Oceanic climates can have much storm activity as they are located in the belt of the stormy westerlies . Many oceanic climates have frequent cloudy or overcast conditions due to the near constant storms and lows tracking over or near them . The annual range of temperatures is smaller than typical climates at these latitudes due to the constant stable marine air masses that pass through oceanic climates , which lack both very warm and very cool fronts . |
Ojibwe | The Ojibwe , Ojibwa , or Chippewa are an Anishinaabeg group of indigenous peoples in North America . They live in Canada and the United States and are one of the largest Indigenous ethnic groups north of the Rio Grande . In Canada , they are the second-largest First Nations population , surpassed only by the Cree . In the United States , they have the fourth-largest population among Native American tribes , surpassed only by the Navajo , Cherokee , and Lakota-Dakota-Nakota people . The Ojibwe people traditionally have spoken the Ojibwe language , a branch of the Algonquian language family . They are part of the Council of Three Fires and the Anishinaabeg , which include the Algonquin , Nipissing , Oji-Cree , Odawa and the Potawatomi . The majority of the Ojibwe people live in Canada . There are 77,940 mainline Ojibwe ; 76,760 Saulteaux and 8,770 Mississaugas , organized in 125 bands , and living from western Quebec to eastern British Columbia . As of 2010 , Ojibwe in the US census population is 170,742 . Ojibwe are known for their birch bark canoes , birch bark scrolls , mining and trade in copper , and cultivation of wild rice . Their Midewiwin Society is well respected as the keeper of detailed and complex scrolls of events , oral history , songs , maps , memories , stories , geometry , and mathematics . The Ojibwe people set the agenda with European-Canadian leaders by signing detailed treaties before they allowed many European settlers into their western areas . In 1745 , they adopted guns from the British to defeat the Dakota people in the Lake Superior area , pushing them to the south and west . |
Olympic_Mountains | The Olympic Mountains are a mountain range on the Olympic Peninsula of western Washington in the United States . The mountains , part of the Pacific Coast Ranges , are not especially high -- Mount Olympus is the highest at 7962 ft ; however , the eastern slopes rise out of Puget Sound and the western slopes are separated from the Pacific Ocean by the 20 to wide Pacific Ocean coastal plain . The western slopes are the wettest place in the 48 contiguous states . Most of the mountains are protected within the bounds of the Olympic National Park . The mountains are spread out across four counties : Clallam , Grays Harbor , Jefferson and Mason . Physiographically , they are a section of the larger Pacific Border province , which is in turn a part of the larger Pacific Mountain System . |
Offer_of_proof | An offer of proof is a kind of motion that a lawyer may present to a judge or to the official presiding over an administrative hearing . It is an explanation made by an attorney to a judge during trial to show why a question which has been objected to as immaterial or irrelevant will lead to evidence of value to proving the case of the lawyer 's client . Often the judge will ask : `` Where is this line of questions going ? '' and the offer of proof is the response . The offer provides the opposition a preview of the questions ( and helps prevent surprise ) , but is essential to overcome the objections . In the context of a trial or a hearing , a presiding judge may issue a ruling denying a party the right to proffer evidence . The party aggrieved by this ruling then has the right to indicate for the record what the evidence would have shown had the adverse ruling not been issued . This is necessary in order to preserve the issue for appeal . In jury trials , offers of proof may be made outside the hearing of the jury . A party may request a motion in limine ( Latin : `` at the threshold '' ) made before the start of a trial requesting that the judge rule that certain evidence may , or may not , be introduced to the jury in a trial . In some cases this may be made at the bench ( with the court reporter taking down every word spoken by the parties and the judge ) or the jury may be excused . It is common for the jury to be excused and for a party to be allowed to continue questioning a witness outside the hearing of the jury until the judge can determine if the evidence sought is relevant and not otherwise excludable . |
Ordinal_regression | In statistics , ordinal regression ( also called `` ordinal classification '' ) is a type of regression analysis used for predicting an ordinal variable , i.e. a variable whose value exists on an arbitrary scale where only the relative ordering between different values is significant . It can be considered an intermediate problem between regression and classification . Examples of ordinal regression are ordered logit and ordered probit . Ordinal regression turns up often in the social sciences , for example in the modeling of human levels of preference ( on a scale from , say , 1 -- 5 for `` very poor '' through `` excellent '' ) , as well as in information retrieval . In machine learning , ordinal regression may also be called ranking learning . |
Northern_Sea_Route | The Northern Sea Route ( Се́верный морско́й путь , Severnyy morskoy put , shortened to Севморпуть , Sevmorput ) is a shipping route officially defined by Russian legislation as lying east of Novaya Zemlya and specifically running along the Russian Arctic coast from the Kara Sea , along Siberia , to the Bering Strait . The entire route lies in Arctic waters and within Russia 's Exclusive Economic Zone ( EEZ ) . Parts are free of ice for only two months per year . The overall route on Russia 's side of the Arctic between North Cape and the Bering Strait has been called the Northeast Passage , analogous to the Northwest Passage on the Canada side . While the Northeast Passage includes all the East Arctic seas and connects the Atlantic and Pacific oceans , the Northern Sea Route does not include the Barents Sea , and it therefore does not reach the Atlantic . Melting Arctic ice caps are likely to increase traffic in and the commercial viability of the Northern Sea Route . One study , for instance , projects , `` remarkable shifts in trade flows between Asia and Europe , diversion of trade within Europe , heavy shipping traffic in the Arctic and a substantial drop in Suez traffic . Projected shifts in trade also imply substantial pressure on an already threatened Arctic ecosystem . '' |
OPEC | Organization of the Petroleum Exporting Countries ( OPEC , -LSB- ˈoʊpɛk -RSB- , or OPEP in several other languages ) is an intergovernmental organization of 14 nations as of May 2017 , founded in 1960 in Baghdad by the first five members ( Iran , Iraq , Kuwait , Saudi Arabia , Venezuela ) , and headquartered since 1965 in Vienna . As of 2016 , the 14 countries accounted for an estimated 44 percent of global oil production and 73 percent of the world 's `` proven '' oil reserves , giving OPEC a major influence on global oil prices that were previously determined by American-dominated multinational oil companies . OPEC 's stated mission is `` to coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets , in order to secure an efficient , economic and regular supply of petroleum to consumers , a steady income to producers , and a fair return on capital for those investing in the petroleum industry . '' The organization is also a significant provider of information about the international oil market . As of May 2017 , OPEC 's members are Algeria , Angola , Ecuador , Equatorial Guinea , Gabon , Iran , Iraq , Kuwait , Libya , Nigeria , Qatar , Saudi Arabia ( the de facto leader ) , United Arab Emirates , and Venezuela , while Indonesia is a former member . Two-thirds of OPEC 's oil production and reserves are in its six Middle Eastern countries that surround the oil-rich Persian Gulf . The formation of OPEC marked a turning point toward national sovereignty over natural resources , and OPEC decisions have come to play a prominent role in the global oil market and international relations . The effect can be particularly strong when wars or civil disorders lead to extended interruptions in supply . In the 1970s , restrictions in oil production led to a dramatic rise in oil prices and OPEC 's revenue and wealth , with long-lasting and far-reaching consequences for the global economy . In the 1980s , OPEC started setting production targets for its member nations ; and generally when the production targets are reduced , oil prices increase , most recently from the organization 's 2008 and 2016 decisions to trim oversupply . Economists often cite OPEC as a textbook example of a cartel that cooperates to reduce market competition , but whose consultations are protected by the doctrine of sovereign immunity under international law . In December 2014 , `` OPEC and the oil men '' ranked as # 3 on Lloyd 's list of `` the top 100 most influential people in the shipping industry '' . However , their influence on international trade is periodically challenged by the expansion of non-OPEC energy sources , and by the recurring temptation for individual OPEC countries to exceed production ceilings and pursue conflicting self-interests . |
Nordic_countries | The Nordic countries or Nordics are a geographical and cultural region in Northern Europe and the North Atlantic , where they are most commonly known as Norden ( lit. : The North ) . They consist of Denmark , Finland , Iceland , Norway , and Sweden , including the associated territories of Greenland , the Faroe Islands , and the Åland Islands . The population of the Nordic countries are mainly Scandinavian or Finnish , with Greenlandic Inuit and the Sami people as indigenous minorities . The native languages are Swedish , Danish , Norwegian , Icelandic and Faroese , all Germanic languages rooted in Old Norse . Native non-Germanic languages are Finnish , Greenlandic and several Sami languages . The main religion is Lutheran Christianity . The Nordic countries have much in common in their way of life , history , their use of Scandinavian languages and social structure . Politically , Nordic countries do not form a separate entity , but they co-operate in the Nordic Council . Especially in English , Scandinavia is sometimes used as a synonym for the Nordic countries , but that term more properly refers to the three monarchies of Denmark , Norway , and Sweden . Geologically , the Scandinavian Peninsula comprise the mainland of Norway and Sweden as well as the northernmost part of Finland . At 3,425,804 square kilometers , the combined area of the Nordic countries would form the 7th-largest country in the world . Uninhabitable icecaps and glaciers comprise about half of this area , mostly in Greenland . In January 2013 , the region had a population of around 26 million people . The Nordic countries cluster near the top in numerous metrics of national performance , including education , economic competitiveness , civil liberties , quality of life , and human development . With only four language groups , the common linguistic heterogeneous heritage is one of the factors making up the Nordic identity . The languages of Danish , Norwegian , Swedish , Icelandic and Faroese are all rooted in Old Norse and Danish , Norwegian and Swedish are considered mutually intelligible . These three dominating languages are taught in schools throughout the Nordic region . Swedish , for example , is a mandatory subject in Finnish schools , since Finland by law is a bilingual country . Danish is mandatory in Faroese and Greenlandic schools , as these insular states are a part of the Danish Realm ( Rigsfællesskabet ) . Iceland also teaches Danish , since Iceland too was a part of the Danish Realm until 1918 . Beside these and the insular Scandinavian languages Faroese and Icelandic , which are also North Germanic languages , there are the Finnic and Sami branches of the Uralic languages , spoken in Finland and in northern Norway , Sweden and Finland , respectively , and Greenlandic , an Eskimo -- Aleut language , spoken in Greenland . The Nordic countries also share , more or less , the Nordic model of economy and social structure : market economy is combined with strong labour unions and a universalist welfare sector financed by heavy taxes . There is a high degree of income redistribution and little social unrest . |
Northwestern_United_States | The Northwestern United States is an informal geographic region of the United States . The region consistently includes the states of Oregon , Washington , and Idaho -- and usually Montana and Wyoming . Some sources include southeast Alaska in the Northwest . The related but distinct term `` Pacific Northwest '' generally excludes areas from the Rockies eastward . The Northwestern United States is a subportion of the Western United States ( which is , itself , even more ambiguous ) . In contrast , states included in the neighboring regions ( Southwestern United States and Great Plains ) and Utah are not simultaneously considered part of both regions . Like the southwestern United States , the Northwest definition has moved westward over time . The current area includes the old Oregon Territory ( created in 1848 -- Oregon , Washington , Idaho , and areas in Montana west of the Continental Divide ) . The region is similar to Federal Region X , which comprises Oregon , Washington , Idaho , and Alaska . It is home to over 14.2 million citizens . Some of the fastest growing cities in this region and in the nation include Seattle , Spokane , Bellevue , Tacoma , Vancouver , Kennewick , Pasco , Yakima , Portland , Eugene , Salem , Boise , Missoula , and Billings . |