Risk management

Risk management is the identification , assessment , and prioritization of risks ( defined in ISO 31000 as the effect of uncertainty on objectives ) followed by coordinated and economical application of resources to minimize , monitor , and control the probability and/or impact of unfortunate events or to maximize the realization of opportunities . Risk management 's objective is to assure uncertainty does not deflect the endeavor from the business goals .   Risks can come from various sources including uncertainty in financial markets , threats from project failures ( at any phase in design , development , production , or sustainment life-cycles ) , legal liabilities , credit risk , accidents , natural causes and disasters , deliberate attack from an adversary , or events of uncertain or unpredictable root-cause . There are two types of events i.e. negative events can be classified as risks while positive events are classified as opportunities . Several risk management standards have been developed including the Project Management Institute , the National Institute of Standards and Technology , actuarial societies , and ISO standards . Methods , definitions and goals vary widely according to whether the risk management method is in the context of project management , security , engineering , industrial processes , financial portfolios , actuarial assessments , or public health and safety .   Strategies to manage threats ( uncertainties with negative consequences ) typically include avoiding the threat , reducing the negative effect or probability of the threat , transferring all or part of the threat to another party , and even retaining some or all of the potential or actual consequences of a particular threat , and the opposites for opportunities ( uncertain future states with benefits ) .   Certain aspects of many of the risk management standards have come under criticism for having no measurable improvement on risk ; whereas the confidence in estimates and decisions seem to increase . For example , it has been shown that one in six IT projects experience cost overruns of 200 % on average , and schedule overruns of 70 % .


River Parrett

The River Parrett flows through the counties of Dorset and Somerset in South West England , from its source in the Thorney Mills springs in the hills around Chedington in Dorset . Flowing northwest through Somerset and the Somerset Levels to its mouth at Burnham-on-Sea , into the Bridgwater Bay nature reserve on the Bristol Channel , the Parrett and its tributaries drain an area of 1700 km2 -- about 50 per cent of Somerset 's land area , with a population of 300,000 .   The Parrett 's main tributaries include the Rivers Tone , Isle , and Yeo , and the River Cary via the King 's Sedgemoor Drain . The 37 mi long river is tidal for 19 mi up to Oath . The fall of the river between Langport and Bridgwater is only 1 ft/mi , so it is prone to frequent flooding in winter and during high tides . Many approaches have been tried since at least the medieval period to reduce the incidence and effect of floods and to drain the surrounding fields .   In Anglo-Saxon times the river formed a boundary between Wessex and Dumnonia . It later served the Port of Bridgwater , and enabled cargoes to be transported inland . The arrival of the railways led to a decline in commercial shipping , and the only working docks are at Dunball . Man 's influence on the river has left a legacy of bridges and industrial artefacts . The Parrett along with its connected waterways and network of drains supports an ecosystem that includes several rare species of flora and fauna . The River Parrett Trail has been established along the banks of the river .


River Thames

The River Thames ( -LSB- tɛmz -RSB- ) is a river that flows through southern England , most notably through London . At 215 mi , it is the longest river entirely in England and the second longest in the United Kingdom , after the River Severn . It also flows through Oxford ( where it is called Isis ) , Reading , Henley-on-Thames and Windsor . The lower reaches of the river are called the Tideway , derived from its long tidal reach up to Teddington Lock . It rises at Thames Head in Gloucestershire , and flows into the North Sea via the Thames Estuary . The Thames drains the whole of Greater London .   Its tidal section , reaching up to Teddington Lock , includes most of its London stretch and has a rise and fall of 7 m. Running through some of the driest parts of mainland Britain and heavily abstracted for drinking water , the Thames ' discharge is low considering its length and breadth : the Severn has a discharge almost twice as large on average despite having a smaller drainage basin . In Scotland , the Tay achieves more than double the average discharge from a drainage basin that is 60 % smaller .   Along its course are 45 navigation locks with accompanying weirs . Its catchment area covers a large part of South Eastern and a small part of Western England and the river is fed by 38 named tributaries . The river contains over 80 islands . With its waters varying from freshwater to almost seawater , the Thames supports a variety of wildlife and has a number of adjoining Sites of Special Scientific Interest , with the largest being in the remaining parts of the North Kent Marshes and covering 5449 ha .   In 2010 , the Thames won the largest environmental award in the world -- the $ 350,000 International Riverprize .


Rob Portman

Robert Jones Portman ( born December 19 , 1955 ) is an American lawyer and the junior United States Senator from Ohio , in office since 2011 . Previously he served as a congressman , as the 14th United States Trade Representative , and as the 35th Director of the Office of Management and Budget .   Born in Cincinnati , Ohio , Portman graduated from Dartmouth College and the University of Michigan Law School . He worked briefly in the White House during the George H. W. Bush administration before entering the U.S. House of Representatives , representing the eastern half of Greater Cincinnati and neighboring counties along the Ohio River , and serving six consecutive terms . Portman resigned from Congress to serve as U.S. Trade Representative from May 2005 to May 2006 . As Trade Representative , Portman is cited for initiating worldwide trade agreements between other countries and the United States , and pursuing claims against China and the European Union at the World Trade Organization . He later served in the George W. Bush administration from May 2006 to June 2007 as Director of the Office of Management and Budget , where he advocated a balanced budget . Portman is married and has three children .   A center-right member of the Republican Party , Portman was elected U.S. Senator in 2010 . He has been listed as a possible Republican vice presidential candidate in the past two presidential elections . In the Senate , Portman was a member of the Congressional Joint Select Committee on Deficit Reduction . Throughout his time in Congress , the Cabinet , and the Senate , Portman has visited over thirty countries , including Israel , China , and Iraq . In 2013 , Portman became the first incumbent statewide or national-level Republican to publicly support legal recognition of same-sex marriage since Lincoln Chafee in 2004 .


Rock music

Rock music is a genre of popular music that originated as `` rock and roll '' in the United States in the early 1950s , and developed into a range of different styles in the 1960s and later , particularly in the United Kingdom and the United States . It has its roots in 1940s and 1950s rock and roll , a style which drew heavily on the African-American genres of blues and rhythm and blues , and from country music . Rock music also drew strongly on a number of other genres such as electric blues and folk , and incorporated influences from jazz , classical and other musical styles . Musically , rock has centered on the electric guitar , usually as part of a rock group with electric bass and drums and one or more singers . Typically , rock is song-based music usually with a 4/4 time signature using a verse-chorus form , but the genre has become extremely diverse . Like pop music , lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political .   By the late 1960s `` classic rock '' period , a number of distinct rock music subgenres had emerged , including hybrids like blues rock , folk rock , country rock , raga rock , and jazz-rock , many of which contributed to the development of psychedelic rock , which was influenced by the countercultural psychedelic and hippie scene . New genres that emerged included progressive rock , which extended the artistic elements ; glam rock , which highlighted showmanship and visual style ; and the diverse and enduring subgenre of heavy metal , which emphasized volume , power , and speed . In the second half of the 1970s , punk rock reacted by producing stripped-down , energetic social and political critiques . Punk was an influence in the 1980s on new wave , post-punk and eventually alternative rock . From the 1990s alternative rock began to dominate rock music and break into the mainstream in the form of grunge , Britpop , and indie rock . Further fusion subgenres have since emerged , including pop punk , rap rock , and rap metal , as well as conscious attempts to revisit rock 's history , including the garage rock/post-punk and synth-pop revivals at the beginning of the 2000s ( decade ) .   Rock music has also embodied and served as the vehicle for cultural and social movements , leading to major subcultures including mods and rockers in the UK and the hippie counterculture that spread out from San Francisco in the US in the 1960s . Similarly , 1970s punk culture spawned the goth and emo subcultures . Inheriting the folk tradition of the protest song , rock music has been associated with political activism as well as changes in social attitudes to race , sex and drug use , and is often seen as an expression of youth revolt against adult consumerism and conformity .


Roger A. Pielke Jr.

Roger A. Pielke Jr. ( born November 2 , 1968 ) is an American political scientist and professor and the director of the Sports Governance Center within the Department of Athletics at the Center for Science and Technology Policy Research at the University of Colorado Boulder .   He previously served in the Environmental Studies Program and was a Fellow of the Cooperative Institute for Research in Environmental Sciences ( CIRES ) where he served as Director of the Center for Science and Technology Policy Research at the University of Colorado Boulder from 2001 to 2007 . Pielke was a visiting scholar at Oxford University 's Saïd Business School in the 2007-2008 academic year .   His interests include understanding the politicization of science ; decision making under uncertainty ; policy education for scientists in areas such as climate change , disaster mitigation , and world trade ; and research on the governance of sports organizations , including FIFA and the NCAA .


Ron Johnson (Wisconsin politician)

Ronald Harold Johnson (born April 8, 1955) is an American businessman and politician serving as the senior United States Senator for Wisconsin. He is a member of the Republican Party. Johnson was first elected to the Senate in 2010, defeating Democratic incumbent Russ Feingold and re-elected in 2016, again defeating Feingold. Before politics, Johnson was chief executive officer of a polyester and plastics manufacturer founded by his brother-in-law.


Ronald Reagan

Ronald Wilson Reagan ( -LSB- ˈrɒnəld_ˈwɪlsən_ˈreɪɡən -RSB- ) ( February 6 , 1911 -- June 5 , 2004 ) was an American politician and actor who served as the 40th President of the United States from 1981 to 1989 . Before his presidency , he was the 33rd Governor of California , from 1967 to 1975 , after a career as a Hollywood actor and union leader .   Raised in a poor family in small towns of northern Illinois , Reagan graduated from Eureka College in 1932 and worked as a sports announcer on several regional radio stations . After moving to Hollywood in 1937 , he became an actor and starred in a few major productions . Reagan was twice elected President of the Screen Actors Guild , the labor union for actors , where he worked to root out Communist influence . In the 1950s , he moved into television and was a motivational speaker at General Electric factories . Having been a lifelong Democrat , his views changed . He became a conservative and in 1962 switched to the Republican Party . In 1964 , Reagan 's speech , `` A Time for Choosing '' , in support of Barry Goldwater 's foundering presidential campaign , earned him national attention as a new conservative spokesman . Building a network of supporters , he was elected Governor of California in 1966 . As governor , Reagan raised taxes , turned a state budget deficit to a surplus , challenged the protesters at the University of California , ordered National Guard troops in during a period of protest movements in 1969 , and was re-elected in 1970 . He twice ran unsuccessfully for the Republican nomination for the U.S. presidency in 1968 and 1976 ; four years later , he easily won the nomination outright , becoming the oldest elected U.S. president up to that time , defeating incumbent Jimmy Carter in 1980 .   Entering the presidency in 1981 , Reagan implemented sweeping new political and economic initiatives . His supply-side economic policies , dubbed `` Reaganomics '' , advocated tax rate reduction to spur economic growth , control of the money supply to curb inflation , economic deregulation , and reduction in government spending . In his first term he survived an assassination attempt , spurred the War on Drugs , and fought public sector labor . Over his two terms , the economy saw a reduction of inflation from 12.5 % to 4.4 % , and an average annual growth of real GDP of 3.4 ; while Reagan did enact cuts in domestic discretionary spending , tax cuts and increased military spending contributed to increased federal outlays overall , even after adjustment for inflation . During his re-election bid , Reagan campaigned on the notion that it was `` Morning in America '' , winning a landslide in 1984 with the largest electoral college victory in American history . Foreign affairs dominated his second term , including ending of the Cold War , the bombing of Libya , and the Iran -- Contra affair . Publicly describing the Soviet Union as an `` evil empire '' , and during his famous speech at the Brandenburg Gate , President Reagan challenged Soviet General Secretary Mikhail Gorbachev to `` tear down this wall ! '' . He transitioned Cold War policy from détente to rollback , by escalating an arms race with the USSR while engaging in talks with Gorbachev , which culminated in the INF Treaty , shrinking both countries ' nuclear arsenals . Reagan 's presidency came during the decline of the Soviet Union and just ten months after the end of his term , the Berlin Wall fell , and on December 26 , 1991 , nearly three years after he left office , the Soviet Union collapsed .   Leaving office in 1989 , Reagan held an approval rating of sixty-eight percent , matching those of Franklin D. Roosevelt , and later Bill Clinton , as the highest ratings for departing presidents in the modern era . He was the first president since Dwight D. Eisenhower to serve two full terms , after a succession of five prior presidents failed to do so . While having planned an active post-presidency , in 1994 Reagan disclosed his diagnosis with Alzheimer 's disease earlier that year , appearing publicly for the last time at the funeral of Richard Nixon ; he died ten years later in 2004 at the age of 93 ; Reagan had the second-longest life out of all the presidents ; the current longest lifespan of a president is held by Gerald Ford , who died two years after Reagan . An icon among Republicans , he is viewed favorably in historian rankings of U.S. presidents , and his tenure constituted a realignment toward conservative policies in the U.S.


Ross Ice Shelf

The Ross Ice Shelf is the largest ice shelf of Antarctica ( an area of roughly 487000 sqkm and about 800 km across : about the size of France ) . It is several hundred metres thick . The nearly vertical ice front to the open sea is more than 600 km long , and between 15 and high above the water surface . Ninety percent of the floating ice , however , is below the water surface .   Most of Ross Ice Shelf is in the Ross Dependency claimed by New Zealand . It floats in , and covers , a large southern portion of the Ross Sea and the entire Roosevelt Island located in the west of the Ross Sea .   The ice shelf is named after Captain Sir James Clark Ross , who discovered it on 28 January 1841 . It was originally called The Barrier , with various adjectives including Great Ice Barrier , as it prevented sailing further south . Ross mapped the ice front eastward to 160 ° W . In 1947 , the US Board on Geographic Names applied the name Ross Shelf Ice to this feature and published it in the original US Antarctic Gazetteer . In January 1953 the name was changed to Ross Ice Shelf ; that name was published in 1956 .


Ross McKitrick

Ross McKitrick is a Canadian economist specializing in environmental economics and policy analysis . He is a professor of economics at the University of Guelph , and a senior fellow of the Fraser Institute . He is a member of the academic advisory boards of the John Deutsch Institute , the Global Warming Policy Foundation , and the Cornwall Alliance for the Stewardship of Creation .   He has authored works about climate change issues , including co-authoring the book Taken By Storm : The Troubled Science , Policy and Politics of Global Warming in 2003 . McKitrick produced a series of videos and articles for the Friends of Science in which he argued that there is a `` pause '' in global warming that reveals flaws in current climate change models . The Friends of Science argue that the sun -- not human emissions of GHG -- is the main driver of climate change .


Rossby wave

Rossby waves , also known as planetary waves , are a natural phenomenon in the atmosphere and oceans of planets that largely owe their properties to rotation of the planet . Rossby waves are a subset of inertial waves .   Atmospheric Rossby waves on Earth are giant meanders in high-altitude winds that have a major influence on weather . These waves are associated with pressure systems and the jet stream . Oceanic Rossby waves move along the thermocline : the boundary between the warm upper layer and the cold deeper part of the ocean .


Roswell UFO incident

In mid-1947 , a United States Air Force balloon crashed at a ranch near Roswell , New Mexico . Following wide initial interest in the crashed `` flying disc '' , the US military stated that it was merely a conventional weather balloon . Interest subsequently waned until the late 1970s , when ufologists began promoting a variety of increasingly elaborate conspiracy theories , claiming that one or more alien spacecraft had crash-landed , and that the extraterrestrial occupants had been recovered by the military , who then engaged in a cover-up .   In the 1990s , the US military published two reports disclosing the true nature of the crashed object : a nuclear test surveillance balloon from Project Mogul . Nevertheless , the Roswell incident continues to be of interest in popular media , and conspiracy theories surrounding the event persist . Roswell has been described as `` the world 's most famous , most exhaustively investigated , and most thoroughly debunked UFO claim '' .


Roy Spencer (scientist)

Roy Warren Spencer ( born December 20 , 1955 ) is a meteorologist , Principal Research Scientist at the University of Alabama in Huntsville , and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer ( AMSR-E ) on NASA 's Aqua satellite . He has served as Senior Scientist for Climate Studies at NASA 's Marshall Space Flight Center .   He is known for his satellite-based temperature monitoring work , for which he was awarded the American Meteorological Society 's Special Award .


Runaway greenhouse effect

A runaway greenhouse effect is a process in which a net positive feedback between surface temperature and atmospheric opacity increases the strength of the greenhouse effect on a planet until its oceans boil away . An example of this is believed to have happened in the early history of Venus . On the Earth , the IPCC states that `` a ` runaway greenhouse effect ' -- analogous to -LSB- that of -RSB- Venus -- appears to have virtually no chance of being induced by anthropogenic activities . ''   Other large-scale climate changes are sometimes loosely called a `` runaway greenhouse effect '' although it is not an appropriate description . For example , it has been hypothesized that large releases of greenhouse gases may have occurred concurrently with the Permian -- Triassic extinction event or Paleocene -- Eocene Thermal Maximum . Other terms , such as `` abrupt climate change '' , or tipping points could be used when describing such scenarios .


Russia

Russia ( -LSB- ˈrʌʃə -RSB- -LSB- Россия , Rossiya , rɐˈsʲijə -RSB- ) , also officially the Russian Federation ( -LSB- Российская Федерация , r = Rossiyskaya Federatsiya , p = rɐˈsʲijskəjə fʲɪdʲɪˈratsɨjə -RSB- ) , is a country in Eurasia . At 17075200 km2 , Russia is the largest country in the world by surface area , covering more than one-eighth of the Earth 's inhabited land area , and the ninth most populous , with over 144 million people at the end of March 2016 . The European western part of the country is much more populated and urbanised than the eastern ; about 77 % of the population live in European Russia . Russia 's capital Moscow is one of the largest cities in the world ; other major urban centers include Saint Petersburg , Novosibirsk , Yekaterinburg , Nizhny Novgorod and Kazan .   Extending across the entirety of Northern Asia and much of Eastern Europe , Russia spans eleven time zones and incorporates a wide range of environments and landforms . From northwest to southeast , Russia shares land borders with Norway , Finland , Estonia , Latvia , Lithuania and Poland ( both with Kaliningrad Oblast ) , Belarus , Ukraine , Georgia , Azerbaijan , Kazakhstan , China , Mongolia , and North Korea . It shares maritime borders with Japan by the Sea of Okhotsk and the U.S. state of Alaska across the Bering Strait .   The East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD . Founded and ruled by a Varangian warrior elite and their descendants , the medieval state of Rus arose in the 9th century . In 988 it adopted Orthodox Christianity from the Byzantine Empire , beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium . Rus ' ultimately disintegrated into a number of smaller states ; most of the Rus ' lands were overrun by the Mongol invasion and became tributaries of the nomadic Golden Horde in the 13th century . The Grand Duchy of Moscow gradually reunified the surrounding Russian principalities , achieved independence from the Golden Horde , and came to dominate the cultural and political legacy of Kievan Rus ' . By the 18th century , the nation had greatly expanded through conquest , annexation , and exploration to become the Russian Empire , which was the third largest empire in history , stretching from Poland on the west to Alaska on the east .   Following the Russian Revolution , the Russian Soviet Federative Socialist Republic became the largest and leading constituent of the Union of Soviet Socialist Republics , the world 's first constitutionally socialist state . The Soviet Union played a decisive role in the Allied victory in World War II , and emerged as a recognized superpower and rival to the United States during the Cold War . The Soviet era saw some of the most significant technological achievements of the 20th century , including the world 's first human-made satellite and the launching of the first humans in space . By the end of 1990 , the Soviet Union had the world 's second largest economy , largest standing military in the world and the largest stockpile of weapons of mass destruction . Following the dissolution of the Soviet Union in 1991 , fifteen independent republics emerged from the USSR : Russia , Ukraine , Belarus , Kazakhstan , Uzbekistan , Armenia , Azerbaijan , Estonia , Georgia , Kyrgyzstan , Latvia , Lithuania , Moldova , Tajikistan , Turkmenistan ; the Russian SFSR reconstituted itself as the Russian Federation and is recognized as the continuing legal personality and sole successor state of the Soviet Union . It is governed as a federal semi-presidential republic .   The Russian economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2015 . Russia 's extensive mineral and energy resources are the largest such reserves in the world , making it one of the leading producers of oil and natural gas globally . The country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction . Russia is a great power as well as a regional power and has been characterised as a potential superpower . It is permanent member of the United Nations Security Council , as well as a member of the G20 , the Council of Europe , the Asia-Pacific Economic Cooperation ( APEC ) , the Shanghai Cooperation Organisation ( SCO ) , the Organization for Security and Co-operation in Europe ( OSCE ) , and the World Trade Organization ( WTO ) , as well as being the leading member of the Commonwealth of Independent States ( CIS ) , the Collective Security Treaty Organization ( CSTO ) and one of the five members of the Eurasian Economic Union ( EEU ) , along with Armenia , Belarus , Kazakhstan , and Kyrgyzstan .


United States intelligence agencies have concluded that there was Russian interference in the 2016 United States elections . In January 2017 , a published U.S. intelligence community assessment expressed `` high confidence '' that the Russian government favored Donald Trump over Hillary Clinton and that Russian President Vladimir Putin personally ordered an `` influence campaign '' to denigrate Clinton and to harm her electoral chances and potential presidency . The report concluded that Russia used disinformation , data thefts , leaks , and social media `` trolls '' in an effort to give an advantage to Trump over Clinton but did not target or compromise vote tallying . These conclusions were reaffirmed by the lead intelligence officials in the Trump administration in May 2017 . Intelligence allies of the U.S. in Europe had found communications between suspected Russian agents and the Trump campaign as early as 2015 . Some media organizations have referred to this interference as `` Kremlingate '' .   On October 7 , 2016 , the Office of the Director of National Intelligence ( DNI ) and the Department of Homeland Security ( DHS ) jointly stated that Russia hacked the Democratic National Committee ( DNC ) servers and Clinton campaign chairman John Podesta 's personal email account and leaked their documents to WikiLeaks .  Several cybersecurity firms stated that the cyberattacks were committed by Russian intelligence groups Fancy Bear and Cozy Bear . In October 2016 , U.S. President Barack Obama directly warned Putin to stop interfering or face `` serious consequences '' . Russian officials initially issued categorical denials of any Russian involvement in any DNC hacks or leaks . In June 2017 , however , in a shift from Russia 's previous blanket denials , Putin suggested that private `` patriotically minded '' Russian hackers could have been responsible for cyberattacks , while continuing to deny government involvement . In January 2017 , Director of National Intelligence James Clapper testified that Russia 's alleged meddling in the 2016 presidential campaign went beyond hacking , and included disinformation such as the dissemination of fake news often promoted on social media . President-elect Trump initially rejected the reports of Russian interference and criticized the intelligence agencies , saying that Democrats were simply reacting to their election loss .   Investigations on Russian influence , including potential collusion between the Trump campaign and Russian officials , were started by the FBI , the Senate Intelligence Committee and the House Intelligence Committee . Six federal agencies have also been investigating possible links and financial ties between the Kremlin and Trump 's associates , including his son-in-law Jared Kushner and advisers Carter Page , Paul Manafort and Roger Stone . In December 2016 , Obama ordered a report on hacking efforts aimed at U.S. elections since 2008 . On December 29 , 2016 , the U.S. expelled 35 Russian diplomats , denied access to two Russia-owned compounds , and broadened existing sanctions on Russian entities and individuals . Russia did not retaliate .   On March 20 , 2017 , FBI director James Comey testified to the House Intelligence Committee that the FBI had been conducting a counter-intelligence investigation about Russian interference since July 2016 , including possible coordination between associates of Trump and Russia . On May 9 , 2017 , in a move that was widely criticized as an attempt to curtail the Russian investigation by the FBI , Trump dismissed Comey . On May 17 , 2017 , Deputy Attorney General Rod Rosenstein appointed former FBI Director Robert Mueller as special counsel in the FBI 's Russian investigation .


Sadovo

Sadovo is a small town in Sadovo Municipality , Plovdiv Province , central Bulgaria , and the administrative center of Plovdiv . The population is 2,600 .   The mayor of Sadovo is Dimitar Zdravkov .


Sahara

The Sahara ( الصحراء الكبرى , , ` the Greatest Desert ' ) is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic . Its area of 9200000 km2 is comparable to the area of the United States .   The desert comprises much of North Africa , excluding the fertile region on the Mediterranean Sea coast , the Atlas Mountains of the Maghreb , and the Nile Valley in Egypt and Sudan . It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west , where the landscape gradually changes from desert to coastal plains . To the south , it is bounded by the Sahel , a belt of semi-arid tropical savanna around the Niger River valley and the Sudan Region of Sub-Saharan Africa .   The Sahara can be divided into several regions including : the western Sahara , the central Ahaggar Mountains , the Tibesti Mountains , the Aïr Mountains , the Ténéré desert , and the Libyan Desert .   The name ` Sahara ' is derived from ( , pronounced -LSB- / / ˈSaHa : ra : -RSB- ) , the plural of the Arabic word for `` desert '' .


Sahel drought

The Sahel has long experienced a series of historic droughts , dating back to at least the 17th century . The Sahel region is a climate zone sandwiched between the African Savannah grasslands to the south and the Sahara desert to the north , across West and Central Africa . While the frequency of drought in the region is thought to have increased from the end of the 19th century , three long droughts have had dramatic environmental and societal effects upon the Sahel nations . Famine followed severe droughts in the 1910s , the 1940s , and the 1960s , 1970s and 1980s , although a partial recovery occurred from 1975-80 . The most recent drought occurred in 2012 .   While at least one particularly severe drought has been confirmed each century since the 17th century , the frequency and severity of recent Sahelian droughts stands out . Famine and dislocation on a massive scale -- from 1968 to 1974 and again in the early and mid-1980s -- was blamed on two spikes in the severity of the 1960-1980s drought period . From the late 1960s to early 1980s famine killed 100,000 people , left 750,000 dependent on food aid , and affected most of the Sahel 's 50 million people . The economies , agriculture , livestock and human populations of much of Mauritania , Mali , Chad , Niger and Burkina Faso ( known as Upper Volta during the time of the drought ) were severely impacted . As disruptive as the droughts of the late 20th century were , evidence of past droughts recorded in Ghanaian lake sediments suggest that multi-decadal megadroughts were common in West Africa over the past 3,000 years and that several droughts lasted far longer and were far more severe .   Since the 1980s , summer rainfall in the Sahel has been increasing ; this has been associated with an increase in vegetation , forming what has been called a ` greening ' of the Sahel . The observed increase in rainfall is accounted for by enhancements in the African easterly jet , which is known to induce wet anomalies . A 2011 study found that the positional shifts in the African easterly jet and African easterly waves accompanied the northward migration of the Sahel rainband .


Salt marsh

A salt marsh or saltmarsh , also known as a coastal salt marsh or a tidal marsh , is a coastal ecosystem in the upper coastal intertidal zone between land and open salt water or brackish water that is regularly flooded by the tides . It is dominated by dense stands of salt-tolerant plants such as herbs , grasses , or low shrubs . These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments . Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters . They also support terrestrial animals and provide coastal protection .


Salt pannes and pools

Salt pannes and pools are water retaining depressions located within salt and brackish marshes . Pools tend to retain water during the summer months between high tides , whereas pannes generally do not . Salt pannes generally start when a mat of organic debris ( known as wrack ) is deposited upon existing vegetation , killing it . This creates a slight depression in the surrounding vegetation which retains water for varying periods of time . Upon successive cycles of inundation and evaporation the panne develops an increased salinity greater than that of the larger body of water . This increased salinity dictates the type of flora and fauna able to grow within the panne . Salt pools are also secondary formations , though the exact mechanism ( s ) of formation are not well understood ; some have predicted they will increase in size and abundance in the future due to rising sea levels .   Salt pannes and pools are unique microhabitats dominated by various species of halophytes , benthic plants and varying estuarine marine life that vary considerably in composition due to a variety of factors :  Substrate type : affects the ability of the depression to hold water .  depth and diameter : affect water temperature and evaporation rate in the depression . A shallow and wide pool will evaporate at a greater rate than a pool of the same volume of water which is deeper and has a smaller surface area . Evaporation rate also affects salinity , the higher the evaporation rate the higher the salinity , with rates as high as a third greater than ocean water .  location within the intertidal zone , whether high marsh or low marsh and distance from the mean low tide mark which affects the length and duration of inundation until the depression is subject to evaporation as well as length of time until the rising tide replenishes the water volume .   These factors affect the types of species which can survive within the various types of salt pannes and pools .   Variants of salt pannes and pools :   Low salt marsh   Low salt marsh panne   Usually devoid of vegetation , that may be present include smooth cordgrass ( Spartina alterniflora ) , marine algae such as knotted wrack ( Ascophyllum nodosum ) and rockweeds ( Fucus spp . ) . The substrate is typically soft , silty mud .   High salt marsh   Arrow-grass ( forb ) panne  Briefly flooded , very shallow with a moderate amount of vegetation usually dominated by Arrow grass ( Triglochin maritimum ) , with the deeper sections possibly remaining unvegetated .   Smooth cord-grass ( short form ) panne  Shallow anaerobic depressions with poor drainage , poor water quality due to low nutrient levels and high concentrations of sulfides and similar compounds which inhibit plant growth . Short form ( 6-12 '' tall ) smooth cord-grass ( Spartina alterniflora ) is the dominant plant species . Typically found on the high salt marsh , but can occasionally be found on the upper margins of low salt marsh .   Salt marsh mosquito panne   Minimal vegetation often found on the upper half of the high salt marsh . It is typically deeper than forb and smooth cord-grass pannes . Usually flooded by the higher of the two spring tides , retains water for 2 -- 3 weeks later until drying out . The female eastern salt marsh mosquito ( Aedes sollicitans ) lays eggs on the exposed surface . The eggs lay dormant until the next time the panne floods .   Widgeon grass ( Ruppia maritima ) - marsh minnow deepwater pool  Pools on the high salt marsh that are semi-permanently and permanently flooded . They are able to sustain populations of Sheephead minnow ( Cyprinodon variegatus variegatus ) , Mummichogs , ( Fundulus heteroclitus ) , and other species of small fish which may become trapped in the pools and benthic species of vegetation . Occasioanally can be found at the upper edge of the low salt marsh .


San Francisco

San Francisco ( initials SF ) ( -LSB- sæn_frənˈsɪskoʊ -RSB- , Spanish for Saint Francis ; Spanish : -LSB- san franˈsisko -RSB- ) , officially the City and County of San Francisco , is the cultural , commercial , and financial center of Northern California . Located at the north end of the San Francisco Peninsula , San Francisco is about 47.9 sqmi in area , making it the smallest county -- and the only consolidated city-county -- within the state of California . With a density of about 18,581 people per square mile ( 7,174 people per km2 ) , San Francisco is the most densely settled large city ( population greater than 200,000 ) in California and the second-most densely populated major city in the United States after New York City . San Francisco is the fourth-most populous city in California , after Los Angeles , San Diego , and San Jose , and the 13th-most populous city in the United States -- with a census-estimated 2016 population of 870,887 . The city and its surrounding areas are known as the San Francisco Bay Area , and are a part of the larger OMB-designated San Jose-San Francisco-Oakland combined statistical area , the fifth most populous in the nation with an estimated population of 8.7 million .   San Francisco was founded on June 29 , 1776 , when colonists from Spain established Presidio of San Francisco at the Golden Gate and Mission San Francisco de Asís a few miles away , all named for St. Francis of Assisi . The California Gold Rush of 1849 brought rapid growth , making it the largest city on the West Coast at the time . San Francisco became a consolidated city-county in 1856 .  After three-quarters of the city was destroyed by the 1906 earthquake and fire , San Francisco was quickly rebuilt , hosting the Panama-Pacific International Exposition nine years later . In World War II , San Francisco was a major port of embarkation for service members shipping out to the Pacific Theater . It then became the birthplace of the United Nations in 1945 . After the war , the confluence of returning servicemen , massive immigration , liberalizing attitudes , along with the rise of the `` hippie '' counterculture , the Sexual Revolution , the Peace Movement growing from opposition to United States involvement in the Vietnam War , and other factors led to the Summer of Love and the gay rights movement , cementing San Francisco as a center of liberal activism in the United States . Politically , the city votes strongly along liberal Democratic Party lines .   A popular tourist destination , San Francisco is known for its cool summers , fog , steep rolling hills , eclectic mix of architecture , and landmarks , including the Golden Gate Bridge , cable cars , the former Alcatraz Federal Penitentiary , Fisherman 's Wharf , and its Chinatown district . San Francisco is also the headquarters of five major banking institutions and various other companies such as Levi Strauss & Co. , Gap Inc. , Salesforce.com , Dropbox , Reddit , Square , Inc. , Dolby , Airbnb , Weebly , Pacific Gas and Electric Company , Yelp , Pinterest , Twitter , Uber , Lyft , Mozilla , Wikimedia Foundation , Craigslist and Weather Underground . It has several nicknames , including `` The City by the Bay '' , `` Fog City '' , `` San Fran '' , and `` Frisco '' , as well as older ones like `` The City that Knows How '' , `` Baghdad by the Bay '' , `` The Paris of the West '' , or simply `` The City '' . , San Francisco is ranked high on world liveability rankings .


San Francisco Bay

San Francisco Bay is a shallow estuary in the U.S. state of California . It is surrounded by a contiguous region known as the San Francisco Bay Area ( often simply `` the Bay Area '' ) , dominated by the large cities San Francisco , Oakland , and San Jose .   San Francisco Bay drains water from approximately 40 percent of California . Water from the Sacramento and San Joaquin rivers , and from the Sierra Nevada mountains , flow into Suisun Bay , which then travels through the Carquinez Strait to meet with the Napa River at the entrance to San Pablo Bay , which connects at its south end to San Francisco Bay . It then connects to the Pacific Ocean via the Golden Gate strait . However , this entire group of interconnected bays is often called the San Francisco Bay .   The bay was designated a Ramsar Wetland of International Importance on February 2 , 2013 .


San Joaquin Valley

The San Joaquin Valley -LSB- ˌsæn_hwɑːˈkiːn -RSB- is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento -- San Joaquin River Delta and is drained by the San Joaquin River . It comprises seven Northern California counties -- all of Kings County ; a majority of Fresno , Merced , Stanislaus counties ; segments of Madera and Tulare counties -- and all of Kern County , in Southern California . Although a majority of the valley is rural , it does contain urban cities such as Fresno , Bakersfield , Stockton , Modesto , Turlock , Porterville , Visalia , Merced , and Hanford .


Santa Ana winds

The Santa Ana winds are strong , extremely dry down-slope winds that originate inland and affect coastal Southern California and northern Baja California . They originate from cool , dry high-pressure air masses in the Great Basin .   Santa Ana winds are known for the hot dry weather that they bring in the fall ( often the hottest of the year ) , but they can arise at other times of the year . They often bring the lowest relative humidities of the year to coastal Southern California . These low humidities , combined with the warm , compressionally-heated airmass , plus high wind speeds , create critical fire weather conditions . Known as `` devil winds '' , Santa Anas are infamous for fanning regional wildfires .


Sarah Palin

Sarah Louise Palin ( -LSB- ˈpeɪlᵻn -RSB- née Heath ; born February 11 , 1964 ) is an American politician , commentator , and author who served as the ninth Governor of Alaska from 2006 until her resignation in 2009 . As the Republican Party nominee for Vice President of the United States in the 2008 election alongside presidential nominee , Arizona Senator John McCain , she was the first Alaskan on the national ticket of a major political party and the first Republican woman selected as a vice presidential candidate . Also , her book Going Rogue has sold more than two million copies .   She was elected to the Wasilla city council in 1992 and became mayor of Wasilla in 1996 . In 2003 , after an unsuccessful run for lieutenant governor , she was appointed chair of the Alaska Oil and Gas Conservation Commission , responsible for overseeing the state 's oil and gas fields for safety and efficiency . She was the youngest person and the first woman to be elected Governor of Alaska .   Since her resignation as Governor , she has endorsed and campaigned for the Tea Party movement as well as several candidates in multiple election cycles , prominently including Donald Trump for President in 2016 . From 2010 to 2015 , she provided political commentary for Fox News . On April 3 , 2014 , Palin premiered her TV show , Amazing America with Sarah Palin , on the Sportsman Channel , which ran until February 12 , 2015 . On July 27 , 2014 , Palin launched the online news network called the Sarah Palin Channel , which was closed on July 4 , 2015 .


Satellite television

Satellite television is a service that delivers television programming to customers by relaying it from a communications satellite orbiting the Earth directly to the customer 's location . The signals are received via an outdoor parabolic antenna usually referred to as a satellite dish and a low-noise block downconverter .   A satellite receiver then decodes the desired television programme for viewing on a television set . Receivers can be external set-top boxes , or a built-in television tuner . Satellite television provides a wide range of channels and services . It is the only television available in many remote geographic areas without terrestrial television or cable television service .   Modern systems signals are relayed from a communications satellite on the Ku band frequencies ( 12 -- 18 GHz ) requiring only a small dish less than a meter in diameter . The first satellite TV systems were an obsolete type now known as television receive-only . These systems received weaker analog signals transmitted in the C-band ( 4 -- 8 GHz ) from FSS type satellites , requiring the use of large 2-3 meter dishes . Consequently , these systems were nicknamed `` big dish '' systems , and were more expensive and less popular .   Early systems used analog signals , but modern ones use digital signals which allow transmission of the modern television standard high-definition television .   Different receivers are required for the two types . Some transmissions and channels are unencrypted and therefore free-to-air or free-to-view , while many other channels are transmitted with encryption ( pay television ) , requiring the customer to subscribe and pay a monthly fee to receive the programming .


Satellite temperature measurements

The temperature of the atmosphere at various altitudes as well as sea and land surface temperatures can be inferred from satellite measurements . These measurements can be used to locate weather fronts , monitor the El Niño-Southern Oscillation , determine the strength of tropical cyclones , study urban heat islands and monitor the global climate . Wildfires , volcanos , and industrial hot spots can also be found via thermal imaging from weather satellites .   Weather satellites do not measure temperature directly . They measure radiances in various wavelength bands . Since 1978 microwave sounding units ( MSUs ) on National Oceanic and Atmospheric Administration polar orbiting satellites have measured the intensity of upwelling microwave radiation from atmospheric oxygen , which is related to the temperature of broad vertical layers of the atmosphere . Measurements of infrared radiation pertaining to sea surface temperature have been collected since 1967 .   Satellite datasets show that over the past four decades the troposphere has warmed and the stratosphere has cooled . Both of these trends are consistent with the influence of increasing atmospheric concentrations of greenhouse gases .


Saturn

Saturn is the sixth planet from the Sun and the second-largest in the Solar System , after Jupiter . It is a gas giant with an average radius about nine times that of Earth . Although it has only one-eighth the average density of Earth , with its larger volume Saturn is just over 95 times more massive . Saturn is named after the Roman god of agriculture ; its astronomical symbol represents the god 's sickle .   Saturn 's interior is probably composed of a core of iron -- nickel and rock ( silicon and oxygen compounds ) . This core is surrounded by a deep layer of metallic hydrogen , an intermediate layer of liquid hydrogen and liquid helium , and finally outside the Frenkel line a gaseous outer layer . Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere . Electrical current within the metallic hydrogen layer is thought to give rise to Saturn 's planetary magnetic field , which is weaker than Earth 's , but has a magnetic moment 580 times that of Earth due to Saturn 's larger size . Saturn 's magnetic field strength is around one-twentieth of Jupiter 's . The outer atmosphere is generally bland and lacking in contrast , although long-lived features can appear . Wind speeds on Saturn can reach 1800 km/h , higher than on Jupiter , but not as high as those on Neptune .   Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs and that is composed mostly of ice particles with a smaller amount of rocky debris and dust . Sixty-two moons are known to orbit Saturn , of which fifty-three are officially named . This does not include the hundreds of moonlets comprising the rings . Titan , Saturn 's largest moon , and the second-largest in the Solar System , is larger than the planet Mercury , although less massive , and is the only moon in the Solar System to have a substantial atmosphere .


Saudi Arabia

Saudi Arabia ( -LSB- saʊ - -RSB- ) , officially the Kingdom of Saudi Arabia ( KSA ) , is an Arab sovereign state in Western Asia constituting the bulk of the Arabian Peninsula .  With a land area of approximately , Saudi Arabia is geographically the fifth-largest state in Asia and second-largest state in the Arab world after Algeria . Saudi Arabia is bordered by Jordan and Iraq to the north , Kuwait to the northeast , Qatar , Bahrain and the United Arab Emirates to the east , Oman to the southeast and Yemen to the south . It is separated from Israel and Egypt by the Gulf of Aqaba . It is the only nation with both a Red Sea coast and a Persian Gulf coast and most of its terrain consists of arid desert and mountains .   The area of modern-day Saudi Arabia formerly consisted of four distinct regions : Hejaz , Najd and parts of Eastern Arabia ( Al-Ahsa ) and Southern Arabia ( ` Asir ) . The Kingdom of Saudi Arabia was founded in 1932 by Ibn Saud . He united the four regions into a single state through a series of conquests beginning in 1902 with the capture of Riyadh , the ancestral home of his family , the House of Saud . Saudi Arabia has since been an absolute monarchy , effectively a hereditary dictatorship governed along Islamic lines . The ultraconservative Wahhabi religious movement within Sunni Islam has been called `` the predominant feature of Saudi culture '' , with its global spread largely financed by the oil and gas trade . Saudi Arabia is sometimes called `` the Land of the Two Holy Mosques '' in reference to Al-Masjid al-Haram ( in Mecca ) and Al-Masjid an-Nabawi ( in Medina ) , the two holiest places in Islam . The state has a total population of 28.7 million , of which 20 million are Saudi nationals and 8 million are foreigners . The state 's official language is Arabic .   Petroleum was discovered on 3 March 1938 and followed up by several other finds in the Eastern Province . Saudi Arabia has since become the world 's largest oil producer and exporter , controlling the world 's second largest oil reserves and the sixth largest gas reserves . The kingdom is categorized as a World Bank high-income economy with a high Human Development Index and is the only Arab country to be part of the G-20 major economies . However , the economy of Saudi Arabia is the least diversified in the Gulf Cooperation Council , lacking any significant service or production sector ( apart from the extraction of resources ) . The state has attracted criticism for its treatment of women and use of capital punishment . Saudi Arabia is a monarchical autocracy , has the fourth highest military expenditure in the world and SIPRI found that Saudi Arabia was the world 's second largest arms importer in 2010 -- 2014 . Saudi Arabia is considered a regional and middle power . In addition to the GCC , it is an active member of the Organisation of Islamic Cooperation and OPEC .


Scarlet fever

Scarlet fever can occur as a result of a group A Streptococcus ( group A strep ) infection . The signs and symptoms include a sore throat , fever , headaches , swollen lymph nodes , and a characteristic rash . The rash is red and feels like sandpaper and the tongue may be red and bumpy . It most commonly affects children between five and fifteen years of age .   Scarlet fever affects a small number of people who have either strep throat or streptococcal skin infections . The bacteria are usually spread by people coughing or sneezing . It can also be spread when a person touches an object that has the bacteria on it and then touches their mouth or nose . The characteristic rash is due to the erythrogenic toxin , a substance produced by some types of the bacterium . The diagnosis is typically confirmed by culturing the throat .   There is no vaccine . Prevention is by frequent handwashing , not sharing personal items , and staying away from other people when sick . The disease is treatable with antibiotics which prevents most complications . Outcomes with scarlet fever are typically good . Long-term complications as a result of scarlet fever include kidney disease , rheumatic heart disease , and arthritis . It was a leading cause of death in children in the early 20th century .


Scenario planning

Scenario planning , also called scenario thinking or scenario analysis , is a strategic planning method that some organizations use to make flexible long-term plans . It is in large part an adaptation and generalization of classic methods used by military intelligence .   The original method was that a group of analysts would generate simulation games for policy makers . The games combine known facts about the future , such as demographics , geography , military , political , industrial information , and mineral reserves , with key driving forces identified by considering social , technical , economic , environmental , and political ( STEEP ) trends .   In business applications , the emphasis on gaming the behavior of opponents was reduced ( shifting more toward a game against nature ) . At Royal Dutch/Shell for example , scenario planning was viewed as changing mindsets about the exogenous part of the world , prior to formulating specific strategies .   Scenario planning may involve aspects of systems thinking , specifically the recognition that many factors may combine in complex ways to create sometime surprising futures ( due to non-linear feedback loops ) . The method also allows the inclusion of factors that are difficult to formalize , such as novel insights about the future , deep shifts in values , unprecedented regulations or inventions . Systems thinking used in conjunction with scenario planning leads to plausible scenario story lines because the causal relationship between factors can be demonstrated . In these cases when scenario planning is integrated with a systems thinking approach to scenario development , it is sometimes referred to as dynamic scenarios .


Science

Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe .   Contemporary science is typically subdivided into the natural sciences , which study the material universe ; the social sciences , which study people and societies ; and the formal sciences , which study logic and mathematics . The formal sciences are often excluded as they do not depend on empirical observations . Disciplines which use science , like engineering and medicine , may also be considered to be applied sciences .   From classical antiquity through the 19th century , science as a type of knowledge was more closely linked to philosophy than it is now , and in the Western world the term `` natural philosophy '' once encompassed fields of study that are today associated with science , such as astronomy , medicine , and physics . However , during the Islamic Golden Age foundations for the scientific method were laid by Ibn al-Haytham in his Book of Optics . While the classification of the material world by the ancient Indians and Greeks into air , earth , fire and water was more philosophical , medieval Middle Easterns used practical and experimental observation to classify materials .   In the 17th and 18th centuries , scientists increasingly sought to formulate knowledge in terms of physical laws . Over the course of the 19th century , the word `` science '' became increasingly associated with the scientific method itself as a disciplined way to study the natural world . It was during this time that scientific disciplines such as biology , chemistry , and physics reached their modern shapes . That same time period also included the origin of the terms `` scientist '' and `` scientific community '' , the founding of scientific institutions , and the increasing significance of their interactions with society and other aspects of culture .


Science, technology, engineering, and mathematics

Science , technology , engineering and mathematics ( STEM , previously SMET ) is a term that refers to the academic disciplines of science , technology , engineering and mathematics . The term is typically used when addressing education policy and curriculum choices in schools to improve competitiveness in science and technology development . It has implications for workforce development , national security concerns and immigration policy .   The acronym arose in common use shortly after an interagency meeting on science education held at the US National Science Foundation chaired by the then NSF director Rita Colwell . A director from the Office of Science division of Workforce Development for Teachers and Scientists , Peter Faletra , suggested the change from the older acronym METS to STEM . Colwell , expressing some dislike for the older acronym , responded by suggesting NSF to institute the change . One of the first NSF projects to use the acronym was STEMTEC , the Science , Technology , Engineering and Math Teacher Education Collaborative at the University of Massachusetts Amherst , which was funded in 1998 .


Science and the Catholic Church

The relationship between the Roman Catholic Church and science is a widely debated subject . Historically , the Church has often been a patron of sciences . It has been prolific in the foundation of schools , universities and hospitals , and many clergy have been active in the sciences . Historians of science such as Pierre Duhem credit medieval Catholic mathematicians and philosophers such as John Buridan , Nicole Oresme , and Roger Bacon as the founders of modern science . Duhem found `` the mechanics and physics , of which modern times are justifiably proud , to proceed by an uninterrupted series of scarcely perceptible improvements from doctrines professed in the heart of the medieval schools . '' Yet , the conflict thesis and other critiques emphasize historical or contemporary conflict between the Catholic Church and science , citing in particular the trial of Galileo as evidence . For its part , the Catholic Church teaches that science and the Christian faith are complementary , as can be seen from the Catechism of the Catholic Church which states in regards to faith and science :  Though faith is above reason , there can never be any real discrepancy between faith and reason . Since the same God who reveals mysteries and infuses faith has bestowed the light of reason on the human mind , God can not deny himself , nor can truth ever contradict truth . ... Consequently , methodical research in all branches of knowledge , provided it is carried out in a truly scientific manner and does not override moral laws , can never conflict with the faith , because the things of the world and the things of faith derive from the same God . The humble and persevering investigator of the secrets of nature is being led , as it were , by the hand of God in spite of himself , for it is God , the conserver of all things , who made them what they are .   Catholic scientists , both religious and lay , have led scientific discovery in many fields . From ancient times , Christian emphasis on practical charity gave rise to the development of systematic nursing and hospitals and the Church remains the single greatest private provider of medical care and research facilities in the world . Following the Fall of Rome , monasteries and convents remained bastions of scholarship in Western Europe and clergymen were the leading scholars of the age -- studying nature , mathematics , and the motion of the stars ( largely for religious purposes ) . During the Middle Ages , the Church founded Europe 's first universities , producing scholars like Robert Grosseteste , Albert the Great , Roger Bacon , and Thomas Aquinas , who helped establish the scientific method . During this period , the Church was also a great patron of engineering for the construction of elaborate cathedrals . Since the Renaissance , Catholic scientists have been credited as fathers of a diverse range of scientific fields : Jean-Baptiste Lamarck ( 1744-1829 ) prefigured the theory of evolution with Lamarckism , Friar Gregor Mendel ( 1822-1884 ) pioneered genetics , and Fr Georges Lemaitre ( 1894-1966 ) proposed the Big Bang cosmological model . The Jesuits have been particularly active , notably in astronomy . Church patronage of sciences continues through elite institutions like the Pontifical Academy of Sciences and Vatican Observatory .   This view of the Church as a patron of sciences is contested by some , who speak either of an historically varied relationship which has shifted , from active and even singular support , to bitter clashes ( with accusations of heresy ) -- or of an enduring intellectual conflict between religion and science . Enlightenment philosophers such as Voltaire were famously dismissive of the achievements of the Middle Ages . In the 19th century , the `` conflict thesis '' emerged to propose an intrinsic conflict or conflicts between the Church and science . The original historical usage of the term asserted that the Church has been in perpetual opposition to science . Later uses of the term denote the Church 's epistemological opposition to science . The thesis interprets the relationship between the Church and science as inevitably leading to public hostility , when religion aggressively challenges new scientific ideas as in the Galileo Affair . An alternative criticism is that the Church opposed particular scientific discoveries that it felt challenged its authority and power -- particularly through the Reformation and on through the Enlightenment . This thesis shifts the emphasis away from the perception of the fundamental incompatibility of religion per se and science-in-general to a critique of the structural reasons for the resistance of the Church as a political organisation .   The Church itself rejects the notion of innate conflict . The Vatican Council ( 1869/70 ) declared that `` Faith and reason are of mutual help to each other . '' The Catholic Encyclopedia of 1912 proffers that `` The conflicts between science and the Church are not real , '' and states that belief in such conflicts are predicated on false assumptions . Pope St. John Paul II summarised the Catholic view of the relationship between faith and reason in the encyclical Fides et Ratio , saying that `` faith and reason are like two wings on which the human spirit rises to the contemplation of truth ; and God has placed in the human heart a desire to know the truth -- in a word , to know himself -- so that , by knowing and loving God , men and women may also come to the fullness of truth about themselves . '' The present Papal astronomer Brother Guy Consolmagno describes science as an `` act of worship '' and as `` a way of getting intimate with the Creator . ''


Scientific consensus on climate change

There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports.  Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors.


Scientific journal

In academic publishing , a scientific journal is a periodical publication intended to further the progress of science , usually by reporting new research . There are thousands of scientific journals in publication , and many more have been published at various points in the past ( see list of scientific journals ) . Most journals are highly specialized , although some of the oldest journals such as Nature publish articles and scientific papers across a wide range of scientific fields . Scientific journals contain articles that have been peer reviewed , in an attempt to ensure that articles meet the journal 's standards of quality , and scientific validity . If the journal 's editor considers the paper appropriate , at least two researchers preferably from the same field check the paper for soundness of its scientific argument , and must agree to publish it . Although scientific journals are superficially similar to professional magazines , they are actually quite different . Issues of a scientific journal are rarely read casually , as one would read a magazine . The publication of the results of research is an essential part of the scientific method . If they are describing experiments or calculations , they must supply enough details that an independent researcher could repeat the experiment or calculation to verify the results . Each such journal article becomes part of the permanent scientific record .   The history of scientific journals dates from 1665 , when the French Journal des sçavans and the English Philosophical Transactions of the Royal Society first began systematically publishing research results . Over a thousand , mostly ephemeral , were founded in the 18th century , and the number has increased rapidly after that .   Articles in scientific journals can be used in research and higher education . Scientific articles allow researchers to keep up to date with the developments of their field and direct their own research . An essential part of a scientific article is citation of earlier work . The impact of articles and journals is often assessed by counting citations ( citation impact ) . Some classes are partially devoted to the explication of classic articles , and seminar classes can consist of the presentation by each student of a classic or current paper . Schoolbooks and textbooks have been written usually only on established topics , while the latest research and more obscure topics are only accessible through scientific articles . In a scientific research group or academic department it is usual for the content of current scientific journals to be discussed in journal clubs . Academic credentials for promotion into academic ranks are established in large part by the number and impact of scientific articles published , and many doctoral programs allow for thesis by publication , where the candidate is required to publish a certain number of scientific articles .   The standards that a journal uses to determine publication can vary widely . Some journals , such as Nature , Science , PNAS , and Physical Review Letters , have a reputation of publishing articles that mark a fundamental breakthrough in their respective fields . In many fields , a formal or informal hierarchy of scientific journals exists ; the most prestigious journal in a field tends to be the most selective in terms of the articles it will select for publication , and usually will also have the highest impact factor . In some countries , journal rankings can be utilized for funding decisions and even evaluation of individual researchers , although they are poorly suited for that purpose .   It is also common for journals to have a regional focus , specializing in publishing papers from a particular country or other geographic region , like African Invertebrates .   Articles tend to be highly technical , representing the latest theoretical research and experimental results in the field of science covered by the journal . They are often incomprehensible to anyone except for researchers in the field and advanced students . In some subjects this is inevitable given the nature of the content . Usually , rigorous rules of scientific writing are enforced by the editors ; however , these rules may vary from journal to journal , especially between journals from different publishers . Articles are usually either original articles reporting completely new results or reviews of current literature . There are also scientific publications that bridge the gap between articles and books by publishing thematic volumes of chapters from different authors .


Scientific method

The scientific method is a body of techniques for investigating phenomena , acquiring new knowledge , or correcting and integrating previous knowledge . To be termed scientific , a method of inquiry is commonly based on empirical or measurable evidence subject to specific principles of reasoning . The Oxford Dictionaries Online define the scientific method as `` a method or procedure that has characterized natural science since the 17th century , consisting in systematic observation , measurement , and experiment , and the formulation , testing , and modification of hypotheses '' . Experiments need to be designed to test hypotheses . The most important part of the scientific method is the experiment .   The scientific method is a continuous process , which usually begins with observations about the natural world . Human beings are naturally inquisitive , so they often come up with questions about things they see or hear and often develop ideas ( hypotheses ) about why things are the way they are . The best hypotheses lead to predictions that can be tested in various ways , including making further observations about nature . In general , the strongest tests of hypotheses come from carefully controlled and replicated experiments that gather empirical data . Depending on how well the tests match the predictions , the original hypothesis may require refinement , alteration , expansion or even rejection . If a particular hypothesis becomes very well supported a general theory may be developed .   Although procedures vary from one field of inquiry to another , identifiable features are frequently shared in common between them . The overall process of the scientific method involves making conjectures ( hypotheses ) , deriving predictions from them as logical consequences , and then carrying out experiments based on those predictions . A hypothesis is a conjecture , based on knowledge obtained while formulating the question . The hypothesis might be very specific or it might be broad . Scientists then test hypotheses by conducting experiments . Under modern interpretations , a scientific hypothesis must be falsifiable , implying that it is possible to identify a possible outcome of an experiment that conflicts with predictions deduced from the hypothesis ; otherwise , the hypothesis can not be meaningfully tested .   The purpose of an experiment is to determine whether observations agree with or conflict with the predictions derived from a hypothesis . Experiments can take place anywhere from a college lab to CERN 's Large Hadron Collider . There are difficulties in a formulaic statement of method , however . Though the scientific method is often presented as a fixed sequence of steps , it represents rather a set of general principles .  Not all steps take place in every scientific inquiry ( or to the same degree ) , and are not always in the same order . Some philosophers and scientists have argued that there is no scientific method , such as Lee Smolin and Paul Feyerabend ( in his Against Method ) . Nola and Sankey remark that `` For some , the whole idea of a theory of scientific method is yester-year 's debate '' .


Scientific modelling

Scientific modelling is a scientific activity , the aim of which is to make a particular part or feature of the world easier to understand , define , quantify , visualize , or simulate by referencing it to existing and usually commonly accepted knowledge . It requires selecting and identifying relevant aspects of a situation in the real world and then using different types of models for different aims , such as conceptual models to better understand , operational models to operationalize , mathematical models to quantify , and graphical models to visualize the subject . Modelling is an essential and inseparable part of many scientific disciplines , each of which have their own ideas about specific types of modelling .   There is also an increasing attention to scientific modelling in fields such as science education , philosophy of science , systems theory , and knowledge visualization . There is growing collection of methods , techniques and meta-theory about all kinds of specialized scientific modelling .


Scientific theory

A scientific theory is an explanation of some aspect of the natural world that can , in accordance with the scientific method , be repeatedly tested , using a predefined protocol of observations and experiments . Established scientific theories have withstood rigorous scrutiny and are a comprehensive form of scientific knowledge .   It is important to note that the definition of a `` scientific theory '' ( often ambiguously contracted to `` theory '' for the sake of brevity , including in this page ) as used in the disciplines of science is significantly different from the common vernacular usage of the word `` theory '' . Per NAS 2008 : `` The formal scientific definition of theory is quite different from the everyday meaning of the word . It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence . '' In everyday non-scientific speech , `` theory '' can imply that something is an unsubstantiated and speculative guess , conjecture , idea , or , hypothesis ; such a usage is the opposite of the word `` theory '' in science . These different usages are comparable to the differing , and often opposing , usages of the term `` prediction '' in science versus `` prediction '' in vernacular speech , denoting a mere hope .   The strength of a scientific theory is related to the diversity of phenomena it can explain . As additional scientific evidence is gathered , a scientific theory may be rejected or modified if it does not fit the new empirical findings ; in such circumstances , a more accurate theory is then desired . In certain cases , the less-accurate unmodified scientific theory can still be treated as a theory if it is useful ( due to its sheer simplicity ) as an approximation under specific conditions ( e.g. , Newton 's laws of motion as an approximation to special relativity at velocities that are small relative to the speed of light ) .   Scientific theories are testable and make falsifiable predictions . They describe the causal elements responsible for a particular natural phenomenon , and are used to explain and predict aspects of the physical universe or specific areas of inquiry ( e.g. , electricity , chemistry , astronomy ) . Scientists use theories as a foundation to gain further scientific knowledge , as well as to accomplish goals such as inventing technology or curing disease .   As with other forms of scientific knowledge , scientific theories are both deductive and inductive in nature and aim for predictive power and explanatory capability .   Paleontologist , evolutionary biologist , and science historian Stephen Jay Gould said , `` ... facts and theories are different things , not rungs in a hierarchy of increasing certainty . Facts are the world ′ s data . Theories are structures of ideas that explain and interpret facts . ''


Scotland

Scotland ( -LSB- ˈskɒt.lənd -RSB- Scots : -LSB- - scoˈskɔt.lənd -RSB- Alba -LSB- ˈal̪ˠapə -RSB- ) is a country that is part of the United Kingdom and covers the northern third of the island of Great Britain . It shares a border with England to the south , and is otherwise surrounded by the Atlantic Ocean , with the North Sea to the east and the North Channel and Irish Sea to the south-west . In addition to the mainland , the country is made up of more than 790 islands , including the Northern Isles and the Hebrides .   The Kingdom of Scotland emerged as an independent sovereign state in the Early Middle Ages and continued to exist until 1707 . By inheritance in 1603 , James VI , King of Scots , became King of England and King of Ireland , thus forming a personal union of the three kingdoms . Scotland subsequently entered into a political union with the Kingdom of England on 1 May 1707 to create the new Kingdom of Great Britain . The union also created a new Parliament of Great Britain , which succeeded both the Parliament of Scotland and the Parliament of England . In 1801 , Great Britain itself entered into a political union with the Kingdom of Ireland to create the United Kingdom of Great Britain and Ireland .   Within Scotland , the monarchy of the United Kingdom has continued to use a variety of styles , titles and other royal symbols of statehood specific to the pre-union Kingdom of Scotland . The legal system within Scotland has also remained separate from those of England and Wales and Northern Ireland ; Scotland constitutes a distinct jurisdiction in both public and private law . The continued existence of legal , educational , religious and other institutions distinct from those in the remainder of the UK have all contributed to the continuation of Scottish culture and national identity since the 1707 union with England .   In 1997 , a Scottish Parliament was re-established , in the form of a devolved unicameral legislature comprising 129 members , having authority over many areas of domestic policy . Scotland is represented in the United Kingdom Parliament by 59 MPs and in the European Parliament by 6 MEPs . Scotland is also a member of the British -- Irish Council , and sends five elected representatives to the British -- Irish Parliamentary Assembly .


Scott Pruitt

Edward Scott Pruitt ( born May 9 , 1968 ) is an American lawyer and Republican politician from the state of Oklahoma who is currently the 14th Administrator of the Environmental Protection Agency . Nominated by President Donald Trump in December 2016 , Pruitt was confirmed by the Senate to lead the EPA on February 17 , 2017 .   Pruitt represented Tulsa and Wagoner Counties in the Oklahoma Senate from 1998 until 2006 . In 2006 , Pruitt narrowly lost to Oklahoma Speaker of the House Todd Hiett in a bid for the Republican nomination for Lieutenant Governor of Oklahoma . In 2010 , Pruitt was elected Attorney General of Oklahoma . In that role , he was viewed as a proponent of federalism , supporting religious freedom laws and opposing abortion rights , same-sex marriage , the Affordable Care Act , and environmental regulations as a self-described `` leading advocate against the EPA 's activist agenda '' . He fought the agency 's efforts on climate and clear air in several lawsuits , often closely coordinating with the fossil fuel industry , which supported him with almost $ 300,000 in campaign contributions . In 2012 , Pruitt was elected as chairman of the Republican Attorneys General Association , and re-elected for a second term in February 2013 .   Pruitt rejects the scientific consensus that human activities are a primary contributor to climate change . He specifically rejects the stance of the scientific community , including US agencies NASA and NOAA , that carbon dioxide is the primary contributor .


Scuba diving

Scuba diving is a mode of underwater diving in which the scuba diver uses a self-contained underwater breathing apparatus ( scuba ) which is completely independent of surface supply , to breathe underwater . Unlike other modes of diving , which rely either on breath-hold or on breathing supplied under pressure from the surface , scuba divers carry their own source of breathing gas , usually compressed air , allowing them greater freedom of movement than with an air line or diver 's umbilical and longer underwater endurance than breath-hold . Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled , and consist of one or more diving cylinders containing breathing gas at high pressure which is supplied to the diver through a diving regulator . They may include additional cylinders for decompression gas or emergency breathing gas . Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases . The volume of gas used is reduced compared to that of open circuit ; therefore , a smaller cylinder or cylinders , may be used for an equivalent dive duration . Rebreathers extend the time spent underwater compared to open circuit for the same gas consumption , they produce fewer bubbles and less noise than scuba which makes them attractive to covert military divers to avoid detection , scientific divers to avoid disturbing marine animals , and media divers to avoid bubble interference .   Scuba diving may be done recreationally or professionally in a number of applications , including scientific , military and public safety roles , but most commercial diving uses surface-supplied diving equipment when this is practicable . Scuba divers engaged in armed forces covert operations may be referred to as frogmen , combat divers or attack swimmers .   A scuba diver primarily moves underwater by using fins attached to the feet , but external propulsion can be provided by a diver propulsion vehicle , or a sled pulled from the surface . Other equipment includes a dive mask to improve underwater vision , a protective diving suit , equipment to control buoyancy , and equipment related to the specific circumstances and purpose of the dive . Scuba divers are trained in the procedures and skills appropriate to their level of certification by instructors affiliated to the diver certification organisations which issue these certifications . These include standard operating procedures for using the equipment and dealing with the general hazards of the underwater environment , and emergency procedures for self-help and assistance of a similarly equipped diver experiencing problems . A minimum level of fitness and health is required by most training organisations , but a higher level of fitness may be appropriate for some applications .


Sea

A sea is a large body of salt water that is surrounded in whole or in part by land . More broadly , `` the sea '' is the interconnected system of Earth 's salty , oceanic waters -- considered as one global ocean or as several principal oceanic divisions . The sea moderates Earth 's climate and has important roles in the water cycle , carbon cycle , and nitrogen cycle . Although the sea has been traveled and explored since prehistory , the modern scientific study of the sea -- oceanography -- dates broadly to the British Challenger expedition of the 1870s . The sea is conventionally divided into up to five large oceanic sections -- including the International Hydrographic Organization 's four named oceans ( the Atlantic , Pacific , Indian , and Arctic ) and the Southern Ocean ; smaller , second-order sections , such as the Mediterranean , are known as seas .   Owing to the present state of continental drift , the Northern Hemisphere is now fairly equally divided between land and sea ( a ratio of about 2:3 ) but the South is overwhelmingly oceanic ( 1:4.7 ) . Salinity in the open ocean is generally in a narrow band around 3.5 % by mass , although this can vary in more landlocked waters , near the mouths of large rivers , or at great depths . About 85 % of the solids in the open sea are sodium chloride . Deep-sea currents are produced by differences in salinity and temperature . Surface currents are formed by the friction of waves produced by the wind and by tides , the changes in local sea level produced by the gravity of the Moon and Sun . The direction of all of these is governed by surface and submarine land masses and by the rotation of the Earth ( the Coriolis effect ) .   Former changes in sea levels have left continental shelves , shallow areas in the sea close to land . These nutrient-rich waters teem with life , which provide humans with substantial supplies of food -- mainly fish , but also shellfish , mammals , and seaweed -- which are both harvested in the wild and farmed . The most diverse areas surround great tropical coral reefs . Whaling in the deep sea was once common but whales ' dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting . Oceanography has established that not all life is restricted to the sunlit surface waters : even under enormous depths and pressures , nutrients streaming from hydrothermal vents support their own unique ecosystem . Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earth 's atmosphere ; both plants and animals first evolved in the sea .   The sea is an essential aspect of human trade , travel , mineral extraction , and power generation . This has also made it essential to warfare and left major cities exposed to earthquakes and volcanoes from nearby faults ; powerful tsunami waves ; and hurricanes , typhoons , and cyclones produced in the tropics . This importance and duality has affected human culture , from early sea gods to the epic poetry of Homer to the changes induced by the Columbian Exchange , from burial at sea to Basho 's haikus to hyperrealist marine art , and inspiring music ranging from the shanties in The Complaynt of Scotland to Rimsky-Korsakov 's `` The Sea and Sinbad 's Ship '' to A-mei 's `` Listen to the Sea '' . It is the scene of leisure activities including swimming , diving , surfing , and sailing . However , population growth , industrialization , and intensive farming have all contributed to present-day marine pollution . Atmospheric carbon dioxide is being absorbed in increasing amounts , lowering its pH in a process known as ocean acidification . The shared nature of the sea has made overfishing an increasing problem .


Sea-level curve

The sea-level curve is the representation of the changes of the sea level throughout the geological history .   The first such curve is the Vail curve or Exxon curve . The names of the curve refer to the fact that in 1977 a team of Exxon geologists from Esso Production Research headed by Peter Vail published a monograph on global eustatic sea-level changes . Their sea-level curve was based on seismic and biostratigraphic data accumulated during petroleum exploration .   The Vail curve ( and the monograph itself ) was the subject of debate among geologists , because it was based on undisclosed commercially confidential stratigraphic data , and hence not independently verifiable . Because of this , there were later efforts to establish a sea-level curve based on non-commercial data .   In 1987 -- 1988 a revised eustatic sea-level curve for the Mesozoic and Cenozoic eras was published , now known as the Haq sea-level curve , in reference to the Pakistani-American Oceanographer Bilal Haq .


SeaLifeBase

SeaLifeBase is a global online database of information about marine life . It aims to provide key information on the taxonomy , distribution and ecology of all marine species in the world apart from finfish . SeaLifeBase is in partnership with the WorldFish Center in Malaysia and the UBC Fisheries Centre at the University of British Columbia . Daniel Pauly is the principal investigator and it is coordinated by Maria Lourdes D. Palomares . , it included descriptions of 74,000 species , 47,700 common names , 12,400 pictures , and references to 31,700 works in the scientific literature . SeaLifeBase complements FishBase , which provides parallel information for finfish .


Sea ice

Sea ice arises as seawater freezes . Because ice is less dense than water , it floats on the ocean 's surface ( as does fresh water ice , which has an even lower density ) . Sea ice covers about 7 % of the Earth 's surface and about 12 % of the world 's oceans . Much of the world 's sea ice is enclosed within the polar ice packs in the Earth 's polar regions : the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean . Polar packs undergo a significant yearly cycling in surface extent , a natural process upon which depends the Arctic ecology , including the ocean 's ecosystems . Due to the action of winds , currents and temperature fluctuations , sea ice is very dynamic , leading to a wide variety of ice types and features . Sea ice may be contrasted with icebergs , which are chunks of ice shelves or glaciers that calve into the ocean . Depending on location , sea ice expanses may also incorporate icebergs .


Sea level

Mean sea level ( MSL ) ( abbreviated simply sea level ) is an average level of the surface of one or more of Earth 's oceans from which heights such as elevations may be measured . MSL is a type of vertical datuma standardised geodetic reference pointthat is used , for example , as a chart datum in cartography and marine navigation , or , in aviation , as the standard sea level at which atmospheric pressure is measured in order to calibrate altitude and , consequently , aircraft flight levels . A common and relatively straightforward mean sea-level standard is the midpoint between a mean low and mean high tide at a particular location .   Sea levels can be affected by many factors and are known to have varied greatly over geological time scales . The careful measurement of variations in MSL can offer insights into ongoing climate change , and sea level rise has been widely quoted as evidence of ongoing global warming .   The term above sea level generally refers to above mean sea level ( AMSL ) .


Sea level rise

A sea level rise is an increase in the volume of water in the world 's oceans , resulting in an increase in global mean sea level . Sea level rise is usually attributed to global climate change by thermal expansion of the water in the oceans and by melting of Ice sheets and glaciers on land . Melting of floating ice shelves or icebergs at sea raises sea levels only slightly .   Sea level rise at specific locations may be more or less than the global average . Local factors might include tectonic effects , subsidence of the land , tides , currents , storms , etc. .  Sea level rise is expected to continue for centuries . Because of the slow inertia , long response time for parts of the climate system , it has been estimated that we are already committed to a sea-level rise of approximately 2.3 m for each degree Celsius of temperature rise within the next 2,000 years . IPCC Summary for Policymakers , AR5 , 2014 , indicated that the global mean sea level rise will continue during the 21st century , very likely at a faster rate than observed from 1971 to 2010 . Projected rates and amounts vary . A January 2017 NOAA report suggests a range of GMSL rise of 0.3 -- 2.5 m possible during the 21st century .   Sea level rises can considerably influence human populations in coastal and island regions and natural environments like marine ecosystems .


Sea surface temperature

Sea surface temperature ( SST ) is the water temperature close to the ocean 's surface . The exact meaning of surface varies according to the measurement method used , but it is between 1 mm and 20 m below the sea surface . Air masses in the Earth 's atmosphere are highly modified by sea surface temperatures within a short distance of the shore . Localized areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass . Warm sea surface temperatures are known to be a cause of tropical cyclogenesis over the Earth 's oceans . Tropical cyclones can also cause a cool wake , due to turbulent mixing of the upper 30 m of the ocean . SST changes diurnally , like the air above it , but to a lesser degree . There is less SST variation on breezy days than on calm days . In addition , ocean currents such as the Atlantic Multidecadal Oscillation ( AMO ) , can effect SST 's on multi-decadal time scales , a major impact results from the global thermohaline circulation , which affects average SST significantly throughout most of the world 's oceans .   Coastal SSTs can cause offshore winds to generate upwelling , which can significantly cool or warm nearby landmasses , but shallower waters over a continental shelf are often warmer . Onshore winds can cause a considerable warm-up even in areas where upwelling is fairly constant , such as the northwest coast of South America . Its values are important within numerical weather prediction as the SST influences the atmosphere above , such as in the formation of sea breezes and sea fog . It is also used to calibrate measurements from weather satellites .


Seagrass

Seagrasses are flowering plants ( angiosperms ) belonging to four families ( Posidoniaceae , Zosteraceae , Hydrocharitaceae and Cymodoceaceae ) , all in the order Alismatales ( in the class of monocotyledons ) , which grow in marine , fully saline environments . There are 12 genera with some 60 species known .


Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water 's surface ( sea level ) , and thus is not an island . Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to 1000 - in height . They are defined by oceanographers as independent features that rise to at least 1000 m above the seafloor , characteristically of conical form . The peaks are often found hundreds to thousands of meters below the surface , and are therefore considered to be within the deep sea . During their evolution over geologic time , the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface . After they have subsided and sunk below the sea surface such flat-top seamounts are called `` guyots '' or `` tablemounts ''   A total of 9,951 seamounts and 283 guyots , covering a total of 8,796,150 km2 have been mapped but only a few have been studied in detail by scientists . Seamounts and guyots are most abundant in the North Pacific Ocean , and follow a distinctive evolutionary pattern of eruption , build-up , subsidence and erosion . In recent years , several active seamounts have been observed , for example Loihi in the Hawaiian Islands .   Because of their abundance , seamounts are one of the most common marine ecosystems in the world . Interactions between seamounts and underwater currents , as well as their elevated position in the water , attract plankton , corals , fish , and marine mammals alike . Their aggregational effect has been noted by the commercial fishing industry , and many seamounts support extensive fisheries . There are ongoing concerns on the negative impact of fishing on seamount ecosystems , and well-documented cases of stock decline , for example with the orange roughy ( Hoplostethus atlanticus ) . 95 % of ecological damage is done by bottom trawling , which scrapes whole ecosystems off seamounts .   Because of their large numbers , many seamounts remain to be properly studied , and even mapped . Bathymetry and satellite altimetry are two technologies working to close the gap . There have been instances where naval vessels have collided with uncharted seamounts ; for example , Muirfield Seamount is named after the ship that struck it in 1973 . However , the greatest danger from seamounts are flank collapses ; as they get older , extrusions seeping in the seamounts put pressure on their sides , causing landslides that have the potential to generate massive tsunamis .


Sean Solomon

Sean Carl Solomon ( born 1945 ) is the director of the Lamont-Doherty Earth Observatory of Columbia University , where he is also the William B. Ransford Professor of Earth and Planetary Science . Before moving to Columbia in 2012 , he was the director of the Department of Terrestrial Magnetism at the Carnegie Institute in Washington , D.C. His research area is in geophysics , including the fields of planetary geology , seismology , marine geophysics , and geodynamics . Solomon is the principal investigator on the NASA MESSENGER mission to Mercury . He is also a team member on the Gravity Recovery and Interior Laboratory mission and the Plume-Lithosphere Undersea Melt Experiment ( PLUME ) .