query: The Obama administration "has been constrained by the Oil Pollution Act of 1990, which basically gives the responsible party the lead role in trying to not only fix the problem, but contain the problem."

positive: Environmental policy of the Donald Trump administration The environmental policy of the Donald Trump administration represents a shift from the policy priorities and goals of his predecessor , Barack Obama . During the campaign Trump often described environmental regulations as an impediment to business . He promised to roll back many regulations and end a moratorium on the leasing of federal coal reserves .   Immediately upon his inauguration , the White House released an `` America First Energy Plan '' , which focused on fossil fuels and did not mention renewable energy . The plan would repeal many Obama policies including the Climate Action Plan and the Waters of the U.S. rule , and limit the Environmental Protection Agency 's mission to protecting air and water quality . Within days of taking office he signed executive orders to approve two controversial pipelines and to require federal review of the Clean Water Rule and the Clean Power Plan . He also invited American manufacturers to suggest what regulations should be eliminated ; industry leaders submitted 168 comments , of which nearly half targeted Environmental Protection Agency rules . In March 2017 he released a proposed 2018 budget which would cut funding for the EPA by 31 % . In May 2017 Congress approved a budget for the balance of the 2017-18 year which cuts the EPA 's funding by 1 % and eliminates no jobs .   Trump 's appointments to key agencies dealing in energy and environmental policy reflected his commitment to deregulation , particularly of the fossil fuel industry . Several of his cabinet picks , such as Rick Perry as Secretary of Energy and Scott Pruitt as Administrator of the Environmental Protection Agency , were of people with a history of opposition to the agency they were named to head .

positive: Joe Biden Joseph Robinette Biden Jr. ( -LSB- ˈdʒoʊsᵻf_rɒbᵻˈnɛt_ˈbaɪdən -RSB- born November 20 , 1942 ) is an American politician who was the 47th Vice President of the United States from 2009 to 2017 , having been jointly elected twice with President Barack Obama . A member of the Democratic Party , he represented Delaware as a United States Senator from 1973 until becoming Vice President in 2009 .   Biden was born in Scranton , Pennsylvania , in 1942 , and lived there for ten years before moving to Delaware . He became an attorney in 1969 , and was elected to the New Castle County council in 1970 . He was first elected to the Senate in 1972 , and became the sixth-youngest senator in U.S. history . He was re-elected to the Senate six times , and was the fourth most senior senator at the time of his resignation to assume the Vice Presidency in 2009 . He was a long-time member and former chairman of the Foreign Relations Committee . He opposed the Gulf War in 1991 , but advocated U.S. and NATO intervention in the Bosnian War in 1994 and 1995 . He voted in favor of the resolution authorizing the Iraq War in 2002 , but opposed the surge of U.S. troops in 2007 . He has also served as chairman of the Senate Judiciary Committee , dealing with issues related to drug policy , crime prevention , and civil liberties , and led the legislative efforts for creation of the Violent Crime Control and Law Enforcement Act , and the Violence Against Women Act . He chaired the Judiciary Committee during the contentious U.S. Supreme Court nominations of Robert Bork and Clarence Thomas .   Biden unsuccessfully sought the Democratic presidential nomination in 1988 and in 2008 , both times dropping out after lackluster showings . In the 2008 U.S. presidential election , Barack Obama chose Biden to be his running mate in the race , which they won . He became the first Roman Catholic , and the first Delawarean , to be Vice President of the United States .   As Vice President in the Obama administration , Biden oversaw the infrastructure spending aimed at counteracting the Great Recession , and U.S. policy toward Iraq up until the withdrawal of U.S. troops in 2011 . His ability to negotiate with congressional Republicans helped bring about legislation such as the Tax Relief , Unemployment Insurance Reauthorization , and Job Creation Act of 2010 that resolved a taxation deadlock , the Budget Control Act of 2011 that resolved that year 's debt ceiling crisis , and the American Taxpayer Relief Act of 2012 that addressed the impending `` fiscal cliff '' . In 2011 , he opposed going ahead with the military mission that resulted in the death of Osama bin Laden . Obama and Biden were re-elected in 2012 . In October 2015 , after months of speculation , Biden chose not to run for President of the United States in 2016 . In December 2016 , he refused to rule out a potential bid for President in 2020 , but announced on January 13 , 2017 , that he would not run , only to seemingly backtrack just four days later , again refusing to rule out a potential bid . On January 12 , 2017 , Obama awarded him the Presidential Medal of Freedom , with distinction . After leaving office , Biden was named the Benjamin Franklin Presidential Practice professor at the University of Pennsylvania .

positive: Barack Obama Barack Hussein Obama II ( -LSB- bəˈrɑːk_huːˈseɪn_oʊˈbɑːmə -RSB- ; born August 4 , 1961 ) is an American politician who served as the 44th President of the United States from 2009 to 2017 . He is the first African American to have served as president . He previously served in the U.S. Senate representing Illinois from 2005 to 2008 , and in the Illinois State Senate from 1997 to 2004 .   Obama was born in Honolulu , Hawaii , two years after the territory was admitted to the Union as the 50th state . Raised largely in Hawaii , Obama also spent one year of his childhood in Washington State and four years in Indonesia . After graduating from Columbia University in 1983 , he worked as a community organizer in Chicago . In 1988 Obama enrolled in Harvard Law School , where he was the first black president of the Harvard Law Review . After graduation , he became a civil rights attorney and professor , teaching constitutional law at the University of Chicago Law School from 1992 to 2004 . Obama represented the 13th District for three terms in the Illinois Senate from 1997 to 2004 , when he ran for the U.S. Senate . Obama received national attention in 2004 , with his unexpected March primary win , his well-received July Democratic National Convention keynote address , and his landslide November election to the Senate . In 2008 , Obama was nominated for president , a year after his campaign began , and after a close primary campaign against Hillary Clinton . He was elected over Republican John McCain , and was inaugurated on January 20 , 2009 . Nine months later , Obama was named the 2009 Nobel Peace Prize laureate .   During his first two years in office , Obama signed many landmark bills . Main reforms were the Patient Protection and Affordable Care Act ( often referred to as `` Obamacare '' ) , the Dodd -- Frank Wall Street Reform and Consumer Protection Act , and the Do n't Ask , Do n't Tell Repeal Act of 2010 . The American Recovery and Reinvestment Act of 2009 and Tax Relief , Unemployment Insurance Reauthorization , and Job Creation Act of 2010 served as economic stimulus amidst the Great Recession , but the GOP regained control of the House of Representatives in 2011 . After a lengthy debate over the national debt limit , Obama signed the Budget Control and the American Taxpayer Relief Acts . In foreign policy , Obama increased U.S. troop levels in Afghanistan , reduced nuclear weapons with the U.S.-Russian New START treaty , and ended military involvement in the Iraq War . He ordered military involvement in Libya in opposition to Muammar Gaddafi , and the military operation that resulted in the death of Osama bin Laden .   After winning re-election by defeating Republican nominee Mitt Romney , Obama was sworn in for a second term in 2013 . During his second term , Obama promoted greater inclusiveness for LGBT Americans , with his administration filing briefs that urged the Supreme Court to strike down same-sex marriage bans as unconstitutional ( United States v. Windsor and Obergefell v. Hodges ) . Obama also advocated gun control in response to the Sandy Hook Elementary School shooting , and issued wide-ranging executive actions concerning climate change and immigration . In foreign policy , Obama ordered military intervention in Iraq in response to gains made by ISIL after the 2011 withdrawal from Iraq , continued the process of ending U.S. combat operations in Afghanistan , promoted discussions that led to the 2015 Paris Agreement on global climate change , initiated the sanctions against Russia following the invasion in Ukraine , brokered a nuclear deal with Iran , and normalized U.S. relations with Cuba .   Obama left office in January 2017 with a 60 % approval rating . He currently resides in Washington , D.C. His presidential library will be built in Chicago .

negative: Jeffrey Zients Jeffrey D. `` Jeff '' Zients ( born November 12 , 1966 ) is an American chief executive officer , management consultant and entrepreneur . From February 2014 to January 2017 , he served as Director of the United States National Economic Council and President Obama 's Economic Advisor . Zients previously served as the acting director of the Office of Management and Budget .   Zients 's assumption of the role of Director of the National Economic Council was delayed by his acceptance of an assignment from President Barack Obama to fix the problems of HealthCare.gov . Zients is widely credited with salvaging HealthCare.gov , and has come to be referred to as `` Mr. Fix-It '' within the Obama Administration .

negative: Technological fix A technological fix , technical fix , technological shortcut or solutionism refers to the attempt of using engineering or technology to solve a problem ( often created by earlier technological interventions ) .   Some references define technological fix as an `` attempt to repair the harm of a technology by modification of the system '' , that might involve modification of the machine and/or modification of the procedures for operating and maintaining it .   Technological fixes are inevitable in modern technology . It has been observed that many technologies , although invented and developed to solve certain perceived problems , often create other problems in the process , known as externalities . In other words , there would be modification of the basic hardware , modification of techniques and procedures , or both .   Technological fix is the idea that all problems can find solutions in better and new technologies . It now is used as a dismissive phrase to describe cheap , quick fixes by using inappropriate technologies ; these fixes often create more problems than they solve , or give people a sense that they have solved the problem .

negative: Constrained generalized inverse In linear algebra , a constrained generalized inverse is obtained by solving a system of linear equations with an additional constraint that the solution is in a given subspace . One also says that the problem is described by a system of constrained linear equations .   In many practical problems , the solution of a linear system of equations   is acceptable only when it is in a certain linear subspace of .   In the following , the orthogonal projection on will be denoted by .  Constrained system of linear equations   has a solution if and only if the unconstrained system of equations   is solvable . If the subspace is a proper subspace of , then the matrix of the unconstrained problem may be singular even if the system matrix of the constrained problem is invertible ( in that case , ) . This means that one needs to use a generalized inverse for the solution of the constrained problem . So , a generalized inverse of is also called a - constrained pseudoinverse of .   An example of a pseudoinverse that can be used for the solution of a constrained problem is the Bott -- Duffin inverse of constrained to , which is defined by the equation   if the inverse on the right-hand-side exists .   Category : Matrices

negative: Job shop scheduling Job shop scheduling ( or job-shop problem ( JSP ) ) is an optimization problem in computer science and operations research in which ideal jobs are assigned to resources at particular times . The most basic version is as follows : We are given n jobs J1 , J2 , ... , Jn of varying processing times , which need to be scheduled on m machines with varying processing power , while trying to minimize the makespan . The makespan is the total length of the schedule ( that is , when all the jobs have finished processing ) . In most practical settings , the problem is presented as an online problem ( dynamic scheduling ) , that is , the decision of scheduling a job can only be made online , when the job is presented to the algorithm .   This problem is one of the best known combinatorial optimization problems , and was the first problem for which competitive analysis was presented , by Graham in 1966 .  Best problem instances for basic model with makespan objective are due to Taillard .

negative: National Oil and Hazardous Substances Pollution Contingency Plan The National Oil and Hazardous Substances Pollution Contingency Plan , more commonly called the National Contingency Plan or NCP , is the United States federal government 's blueprint for responding to oil spills and hazardous substance releases . It documents national response capability and is intended to promote overall coordination among the hierarchy of responders and contingency plans .   The first National Contingency Plan was developed and published in 1968 in response to a massive oil spill from the oil tanker Torrey Canyon off the coast of England that occurred a year earlier . More than 37 million gallons of crude oil spilled into the water and caused massive environmental damage . To avoid the problems faced by response officials involved in the incident , U.S. officials developed a coordinated approach to cope with potential spills in U.S. waters . The 1968 plan provided the first comprehensive system of accident reporting , spill containment , and cleanup . It also established a response headquarters , a national reaction team , and regional reaction teams ( precursors to the current National Response Team and Regional Response Teams ) .   Congress has broadened the scope of the National Contingency Plan over the years . As required by the Clean Water Act of 1972 , the NCP was revised the following year to include a framework for responding to hazardous substance spills as well as oil discharges . Following the passage of Superfund legislation in 1980 , the NCP was broadened to cover releases at hazardous waste sites requiring emergency removal actions . Over the years , additional revisions have been made to the NCP to keep pace with the enactment of legislation . The latest revisions to the NCP were finalized in 1994 to reflect the oil spill provisions of the Oil Pollution Act of 1990 .   Under the National Contingency Plan , federal agencies should : ( 1 ) Plan for emergencies and develop procedures for addressing oil discharges and releases of hazardous substances , pollutants , or contaminants ; ( 2 ) Coordinate their planning , preparedness , and response activities with one another ; ( 3 ) Coordinate their planning , preparedness , and response activities with affected states , local governments , and private entities ; and ( 4 ) Make available those facilities or resources that may be useful in a response situation , consistent with agency authorities and capabilities .   Once a response has been triggered , the USCG or USEPA `` is authorized to initiate and , in the case of a discharge posing a substantial threat to public health or welfare of the United States is required to initiate and direct , appropriate response activities when the Administrator or Secretary determines that any oil or  CWA hazardous substance is discharged or there is a substantial threat of such discharge from any vessel or offshore or onshore facility into or on the navigable  waters of the United States , on the adjoining shorelines to the navigable waters , into or on the waters of the exclusive economic zone , or that may affect natural resources belonging to , appertaining to , or under exclusive management authority of the United States '' . The federal On-Scene Coordinator ( OSC ) `` directs response efforts and coordinates all other efforts at the scene of a discharge or release ''

negative: Air Pollution in Canada Air pollution in Canada arises from the increasing airborne chemicals , matter and biological materials in the air . These factors cause harm to human health , the environment and to the economy . In the Canadian context , the main contributor of air pollution stems from burning fossil fuels for power and energy . Fossil fuels continue to be the main source of fuel for Canadians , even though the government is aware of the negative effects that it has on the environment and human health . Air pollution in Canada continues to be an issue due to the pressures with climate change , increased urbanization and continued reliance on vehicles as the primary source of transportation .   A major contributor to the problem of Canadian air pollution are the Alberta Oil Sands . Though they are not closely related to major Canadian Metropolitan Areas , the quality of mostly rural Northern Alberta is poorer than areas of similar population densities in Canada . Toronto and other Canadian municipalities face environmental problems associated with air pollution due to industrial chemicals .   Air pollution is Canada continues to negatively affect the environment , leading to an increase in health problems for Canadians , especially regarding leukemia . Air pollution has increased the rate of hospital visits per year and is currently causing premature deaths .   There are current policy responses to combat the increasing rate of air pollution in Canada . The agreement is a response to Canada 's transportation and energy production infrastructure as they contribute to the problem of Air Pollution . The Canadian and United States federal governments have required each other to reduce air pollution by specific amounts annually through detailed reporting .

negative: Quadratically constrained quadratic program In mathematical optimization , a quadratically constrained quadratic program ( QCQP ) is an optimization problem in which both the objective function and the constraints are quadratic functions . It has the form   where P0 , ... Pm are n-by-n matrices and x ∈ Rn is the optimization variable .   If P0 , ... Pm are all positive semidefinite , then the problem is convex . If these matrices are neither positive nor negative semidefinite , the problem is non-convex . If P1 , ... Pm are all zero , then the constraints are in fact linear and the problem is a quadratic program .

negative: Obstacle problem The obstacle problem is a classic motivating example in the mathematical study of variational inequalities and free boundary problems . The problem is to find the equilibrium position of an elastic membrane whose boundary is held fixed , and which is constrained to lie above a given obstacle . It is deeply related to the study of minimal surfaces and the capacity of a set in potential theory as well . Applications include the study of fluid filtration in porous media , constrained heating , elasto-plasticity , optimal control , and financial mathematics .   The mathematical formulation of the problem is to seek minimizers of the Dirichlet energy functional ,   in some domain where the functions represent the vertical displacement of the membrane . In addition to satisfying Dirichlet boundary conditions corresponding to the fixed boundary of the membrane , the functions are in addition constrained to be greater than some given obstacle function . The solution breaks down into a region where the solution is equal to the obstacle function , known as the contact set , and a region where the solution is above the obstacle . The interface between the two regions is the free boundary .   In general , the solution is continuous and possesses Lipschitz continuous first derivatives , but that the solution is generally discontinuous in the second derivatives across the free boundary . The free boundary is characterized as a Hölder continuous surface except at certain singular points , which reside on a smooth manifold .

negative: Nurse scheduling problem The nurse scheduling problem ( NSP ) , also called the nurse rostering problem ( NRP ) , is the operations research problem of finding an optimal way to assign nurses to shifts , typically with a set of hard constraints which all valid solutions must follow , and a set of soft constraints which define the relative quality of valid solutions . Solutions to the nurse scheduling problem can be applied to constrained scheduling problems in other fields .   The nurse scheduling problem has been studied since before 1969 , and is known to have NP-hard complexity .

negative: Arthur–Merlin protocol In computational complexity theory , an Arthur -- Merlin protocol is an interactive proof system in which the verifier 's coin tosses are constrained to be public ( i.e. known to the prover too ) . This notion was introduced by . proved that all languages with interactive proofs of arbitrary length with private coins also have interactive proofs with public coins .   Given two participants in the protocol called Arthur and Merlin respectively , the basic assumption is that Arthur is a standard computer ( or verifier ) equipped with a random number generating device , while Merlin is effectively an oracle with infinite computational power ( also known as a prover ) ; but Merlin is not necessarily honest , so Arthur must analyze the information provided by Merlin in response to Arthur 's queries and decide the problem itself . A problem is considered to be solvable by this protocol if whenever the answer is `` yes '' , Merlin has some series of responses which will cause Arthur to accept at least of the time , and if whenever the answer is `` no '' , Arthur will never accept more than of the time . Thus , Arthur acts as a probabilistic polynomial-time verifier , assuming it is allotted polynomial time to make its decisions and queries .

negative: Vaccine vial monitor A vaccine vial monitor ( VVM ) is a thermochromic label put on vials containing vaccines which gives a visual indication of whether the vaccine has been kept at a temperature which preserves its potency . The labels were designed in response to the problem of delivering vaccines to developing countries where the cold chain is difficult to preserve , and where formerly vaccines were being rendered inactive and administered ineffectively due to their having been denatured by exposure to ambient temperature .

negative: Readers–writers problem In computer science , the readers-writers problems are examples of a common computing problem in concurrency . There are at least three variations of the problems , which deal with situations in which many threads try to access the same shared resource at one time . Some threads may read and some may write , with the constraint that no process may access the shared resource for either reading or writing while another process is in the act of writing to it . ( In particular , it is allowed for two or more readers to access the share at the same time . ) A readers-writer lock is a data structure that solves one or more of the readers-writers problems .   The basic reader-writers problem was first formulated and solved by Courtois et al. .

negative: NP-intermediate In computational complexity , problems that are in the complexity class NP but are neither in the class P nor NP-complete are called NP-intermediate , and the class of such problems is called NPI . Ladner 's theorem , shown in 1975 by Richard E. Ladner , is a result asserting that , if P ≠ NP , then NPI is not empty ; that is , NP contains problems that are neither in P nor NP-complete . Since the other direction is trivial , it follows that P = NP if and only if NPI is empty .   Under the assumption that P ≠ NP , Ladner explicitly constructs a problem in NPI , although this problem is artificial and otherwise uninteresting . It is an open question whether any `` natural '' problem has the same property : Schaefer 's dichotomy theorem provides conditions under which classes of constrained Boolean satisfiability problems can not be in NPI . Some problems that are considered good candidates for being NP-intermediate are the graph isomorphism problem , factoring , and computing the discrete logarithm .

negative: Hold-up problem In economics , the hold-up problem ( or commitment problem ) is central to the theory of incomplete contracts and shows the difficulty in writing complete contracts . A hold-up problem arises when two factors are present :  Parties to a future transaction must make noncontractible relationship-specific investments before the transaction takes place .  The specific form of the optimal transaction ( such as quality-level specifications , time of delivery , what quantity of units ) can not be determined with certainty beforehand .  The hold-up problem is a situation where two parties may be able to work most efficiently by cooperating but refrain from doing so because of concerns that they may give the other party increased bargaining power , and thereby reduce their own profits . When party A has made a prior commitment to a relationship with party B , the latter can ` hold up ' the former for the value of that commitment . The hold-up problem leads to severe economic cost and might also lead to underinvestment .

negative: Fixed-radius near neighbors In computational geometry , the fixed-radius near neighbor problem is a variant of the nearest neighbor search problem . In the fixed-radius near neighbor problem , one is given as input a set of points in d-dimensional Euclidean space and a fixed distance Δ . One must design a data structure that , given a query point q , efficiently reports the points of the data structure that are within distance Δ of q . The problem has long been studied ; cites a 1966 paper by Levinthal that uses this technique as part of a system for visualizing molecular structures , and it has many other applications .

negative: Knapsack problem The knapsack problem or rucksack problem is a problem in combinatorial optimization : Given a set of items , each with a weight and a value , determine the number of each item to include in a collection so that the total weight is less than or equal to a given limit and the total value is as large as possible . It derives its name from the problem faced by someone who is constrained by a fixed-size knapsack and must fill it with the most valuable items .   The problem often arises in resource allocation where there are financial constraints and is studied in fields such as combinatorics , computer science , complexity theory , cryptography , applied mathematics , and daily fantasy sports .   The knapsack problem has been studied for more than a century , with early works dating as far back as 1897 . The name `` knapsack problem '' dates back to the early works of mathematician Tobias Dantzig ( 1884 -- 1956 ) , and refers to the commonplace problem of packing your most valuable or useful items without overloading your luggage .

negative: Penalty method Penalty methods are a certain class of algorithms for solving constrained optimization problems .   A penalty method replaces a constrained optimization problem by a series of unconstrained problems whose solutions ideally converge to the solution of the original constrained problem . The unconstrained problems are formed by adding a term , called a penalty function , to the objective function that consists of a penalty parameter multiplied by a measure of violation of the constraints . The measure of violation is nonzero when the constraints are violated and is zero in the region where constraints are not violated .

negative: Environmental issues in Kuwait Located in the Middle East , between Saudi Arabia and Iraq , Kuwait is a relatively small country that has been the center of many political and economic issues over the past few decades . These problems include corruption of the Kuwaiti government by many terrorist organizations and domestic violence to maintain the status quo of the oil industry elite . Stemming from these tensions , Kuwait as well as other countries in the region , including Iran , Iraq , and Qatar face threats from environmental issues . A loss of agriculture due to climate change , pollution from the country 's oil industry and Oil Fires of 1991 as well as damages to agriculture and biodiversity are just some of the common environmental issues . The Kuwaiti government has worked to mitigate and adapt to these issues through policy and the creation of agencies to research , educated and inform about environmental problems , their sources , and their effects .   The general environmental issues in Kuwait include but are not limited to climate change , loss of agriculture , loss of biodiversity , air pollution and water pollution .

negative: Parameterized complexity In computer science , parameterized complexity is a branch of computational complexity theory that focuses on classifying computational problems according to their inherent difficulty with respect to multiple parameters of the input or output . The complexity of a problem is then measured as a function in those parameters . This allows the classification of NP-hard problems on a finer scale than in the classical setting , where the complexity of a problem is only measured by the number of bits in the input .  The first systematic work on parameterized complexity was done by .   Under the assumption that P ≠ NP , there exist many natural problems that require superpolynomial running time when complexity is measured in terms of the input size only , but that are computable in a time that is polynomial in the input size and exponential or worse in a parameter . Hence , if is fixed at a small value and the growth of the function over is relatively small then such problems can still be considered `` tractable '' despite their traditional classification as `` intractable '' .   The existence of efficient , exact , and deterministic solving algorithms for NP-complete , or otherwise NP-hard , problems is considered unlikely , if input parameters are not fixed ; all known solving algorithms for these problems require time that is exponential ( or at least superpolynomial ) in the total size of the input . However , some problems can be solved by algorithms that are exponential only in the size of a fixed parameter while polynomial in the size of the input . Such an algorithm is called a fixed-parameter tractable ( fpt - ) algorithm , because the problem can be solved efficiently for small values of the fixed parameter .   Problems in which some parameter is fixed are called parameterized problems . A parameterized problem that allows for such an fpt-algorithm is said to be a fixed-parameter tractable problem and belongs to the class , and the early name of the theory of parameterized complexity was fixed-parameter tractability .   Many problems have the following form : given an object and a nonnegative integer , does have some property that depends on ? For instance , for the vertex cover problem , the parameter can be the number of vertices in the cover . In many applications , for example when modelling error correction , one can assume the parameter to be `` small '' compared to the total input size . Then it is interesting to see whether we can find an algorithm which is exponential only in , and not in the input size .   In this way , parameterized complexity can be seen as two-dimensional complexity theory . This concept is formalized as follows :   A parameterized problem is a language , where is a finite alphabet . The second component is called the parameter of the problem .   A parameterized problem is fixed-parameter tractable if the question `` ? '' can be decided in running time , where is an arbitrary function depending only on . The corresponding complexity class is called FPT .   For example , there is an algorithm which solves the vertex cover problem in time , where is the number of vertices and is the size of the vertex cover . This means that vertex cover is fixed-parameter tractable with the size of the solution as the parameter .

negative: Source separation Source separation problems in digital signal processing are those in which several signals have been mixed together into a combined signal and the objective is to recover the original component signals from the combined signal . The classical example of a source separation problem is the cocktail party problem , where a number of people are talking simultaneously in a room ( for example , at a cocktail party ) , and a listener is trying to follow one of the discussions . The human brain can handle this sort of auditory source separation problem , but it is a difficult problem in digital signal processing . This was first analyzed by Colin Cherry .   Several approaches have been proposed for the solution of this problem but development is currently still very much in progress . Some of the more successful approaches are principal components analysis and independent component analysis , which work well when there are no delays or echoes present ; that is , the problem is simplified a great deal . The field of computational auditory scene analysis attempts to achieve auditory source separation using an approach that is based on human hearing .   The human brain must also solve this problem in real time . In human perception this ability is commonly referred to as auditory scene analysis or the cocktail party effect .

negative: Suramula Suramula is a river in Khashuri Municipality , and a left tributary of the Kura River . It starts at the left slope of Likhi Range , 1200 m above sea level , and runs a length of 42 km . The basin is 719 km2 . This river is nourished by rain , snow , and groundwater . It is known to flood in the spring and in autumn , but it lacks water in winter .   This river is polluted with substances like nitrite nitrogen . It once was polluted with excessive amounts of iron , although this problem has since been fixed .

negative: Sun-Ni law Sun-Ni 's Law ( or Sun and Ni 's Law , also known as memory-bounded speedup ) , is a memory-bounded speedup model which states that as computing power increases the corresponding increase in problem size is constrained by the system 's memory capacity . In general , as a system grows in computational power , the problems run on the system increase in size . Analogous to Amdahl 's law , which says that the problem size remains constant as system sizes grow , and Gustafson 's law , which proposes that the problem size should scale but be bound by a fixed amount of time , Sun-Ni 's Law states the problem size should scale but be bound by the memory capacity of the system . Sun-Ni 's Law was initially proposed by Xian-He Sun and Lionel Ni at the Proceedings of IEEE Supercomputing Conference 1990 .   With the increasing disparity between CPU speed and memory data access latency , application execution time often depends on the memory speed of the system . As predicted by Sun and Ni , data access has become the premier performance bottleneck for high-end computing . From this fact one can see the intuition behind Sun-Ni 's Law , as system resources increase , applications are often bottlenecked by memory speed and bandwidth , thus an application can achieve a larger speedup by utilizing all the memory capacity in the system . Sun-Ni 's Law can be applied to different layers of a memory hierarchy system , from L1 cache to main memory . Through its memory-bounded function , W = G ( M ) , it reveals the trade-off between computing and memory in algorithm and system architecture design .   All three speedup models , Sun-Ni , Gustafson , and Amdahl , provide a metric to analyze speedup for Parallel computing . Amdahl 's law focuses on the time reduction for a given fixed-size problem . Amdahl 's law states that the sequential portion of the problem ( algorithm ) limits the total speedup that can be achieved as system resources increase . Gustafson 's law suggests that it is beneficial to build a large-scale parallel system as the speedup can grow linearly with the system size if the problem size is scaled up to maintain a fixed execution time . Yet as memory access latency often becomes the dominant factor in an application 's execution time , applications may not scale up to meet the time bound constraint . Sun-Ni 's Law , instead of constraining the problem size by time , constrains the problem by the memory capacity of the system , or in other words bounds based on memory . Sun-Ni 's Law is a generalization of Amdahl 's Law and Gustafson 's Law . When the memory-bounded function G ( M ) = 1 , it resolves to Amdahl 's law , when the memory-bounded function G ( M ) = m , the number of processors , it resolves to Gustafson 's Law .

negative: Jeep problem The jeep problem , desert crossing problem or exploration problem is a mathematics problem in which a jeep must maximise the distance it can travel into a desert with a given quantity of fuel . The jeep can only carry a fixed and limited amount of fuel , but it can leave fuel and collect fuel at fuel dumps anywhere in the desert .   The problem was solved by N. J. Fine in 1947 .

negative: Packing problems Packing problems are a class of optimization problems in mathematics that involve attempting to pack objects together into containers . The goal is to either pack a single container as densely as possible or pack all objects using as few containers as possible . Many of these problems can be related to real life packaging , storage and transportation issues . Each packing problem has a dual covering problem , which asks how many of the same objects are required to completely cover every region of the container , where objects are allowed to overlap .   In a Bin packing problem , you are given :  ` containers ' ( usually a single two - or three-dimensional convex region , or an infinite space )  A set of ` objects ' some or all of which must be packed into one or more containers . The set may contain different objects with their sizes specified , or a single object of a fixed dimension that can be used repeatedly .   Usually the packing must be without overlaps between goods and other goods or the container walls . In some variants , the aim is to find the configuration that packs a single container with the maximal density . More commonly , the aim is to pack all the objects into as few containers as possible . In some variants the overlapping ( of objects with each other and/or with the boundary of the container ) is allowed but should be minimized .

negative: Reduced cost In linear programming , reduced cost , or opportunity cost , is the amount by which an objective function coefficient would have to improve ( so increase for maximization problem , decrease for minimization problem ) before it would be possible for a corresponding variable to assume a positive value in the optimal solution . It is the cost for increasing a variable by a small amount , i.e. , the first derivative from a certain point on the polyhedron that constrains the problem . When the point is a vertex in the polyhedron , the variable with the most extreme cost , negatively for minimization and positively maximization , is sometimes referred to as the steepest edge .   Given a system minimize subject to , the reduced cost vector can be computed as , where is the dual cost vector .   It follows directly that for a minimization problem , any non-basic variables at their lower bounds with strictly negative reduced costs are eligible to enter that basis , while any basic variables must have a reduced cost that is exactly 0 . For a maximization problem , the non-basic variables at their lower bounds that are eligible for entering the basis have a strictly positive reduced cost .

negative: Petroleum transport Petroleum transport is the transportation of petroleum and derivatives such as gasoline ( petrol ) . Petroleum is transported via rail cars , trucks , tanker vessels , and through pipelines . Which method is used to move this oil depends on the amount that is being moved and where it is being moved to . The biggest problems with moving this oil are pollution and the chance that the oil can spill . Petroleum oil is very hard to clean up and is very toxic to living animals .

negative: International Society of Doctors for the Environment The International Society of Doctors for the Environment ( ISDE ) is an NGO , founded at Cortona on 25 November 1990 , by doctors of various nationalities , in order to gather all doctors interested in medical problems related to ecological problems , spread awareness of the connection between environmental pollution and human health , start and support initiatives from local to global levels , and to reduce or eliminate sources of pollution and environmental pollution . ISDE has consultative status with the WHO and the United Nations Economic and Social Council .

negative: Hindsight bias Hindsight bias , also known as the knew-it-all-along effect or creeping determinism , is the inclination , after an event has occurred , to see the event as having been predictable , despite there having been little or no objective basis for predicting it . It is a multifaceted phenomenon that can affect different stages of designs , processes , contexts , and situations . Hindsight bias may cause memory distortion , where the recollection and reconstruction of content can lead to false theoretical outcomes . It has been suggested that the effect can cause extreme methodological problems while trying to analyze , understand , and interpret results in experimental studies . A basic example of the hindsight bias is when , after viewing the outcome of a potentially unforeseeable event , a person believes he or she `` knew it all along '' . Such examples are present in the writings of historians describing outcomes of battles , physicians recalling clinical trials , and in judicial systems trying to attribute responsibility and predictability of accidents .

negative: Differential evolution In evolutionary computation , differential evolution ( DE ) is a method that optimizes a problem by iteratively trying to improve a candidate solution with regard to a given measure of quality . Such methods are commonly known as metaheuristics as they make few or no assumptions about the problem being optimized and can search very large spaces of candidate solutions . However , metaheuristics such as DE do not guarantee an optimal solution is ever found .   DE is used for multidimensional real-valued functions but does not use the gradient of the problem being optimized , which means DE does not require for the optimization problem to be differentiable as is required by classic optimization methods such as gradient descent and quasi-newton methods . DE can therefore also be used on optimization problems that are not even continuous , are noisy , change over time , etc. .   DE optimizes a problem by maintaining a population of candidate solutions and creating new candidate solutions by combining existing ones according to its simple formulae , and then keeping whichever candidate solution has the best score or fitness on the optimization problem at hand . In this way the optimization problem is treated as a black box that merely provides a measure of quality given a candidate solution and the gradient is therefore not needed .   DE is originally due to Storn and Price . Books have been published on theoretical and practical aspects of using DE in parallel computing , multiobjective optimization , constrained optimization , and the books also contain surveys of application areas . Surveys on the multi-faceted research aspects of DE can be found in journal articles .

negative: NP-hardness NP-hardness ( non-deterministic polynomial-time hard ) , in computational complexity theory , is the defining property of a class of problems that are , informally , `` at least as hard as the hardest problems in NP '' . More precisely , a problem H is NP-hard when every problem L in NP can be reduced in polynomial time to H , that is : assuming a solution for H takes 1 unit time , we can use H 's solution to solve L in polynomial time . As a consequence , finding a polynomial algorithm to solve any NP-hard problem would give polynomial algorithms for all the problems in NP , which is unlikely as many of them are considered hard .   A common misconception is that the NP in `` NP-hard '' stands for `` non-polynomial '' when in fact it stands for `` Non-deterministic Polynomial acceptable problems '' . Although it is suspected that there are no polynomial-time algorithms for NP-hard problems , this has not been proven . Moreover , the class P in which all problems can be solved in polynomial time , is contained in the NP class .

negative: Family law in British Columbia There are two courts that handle almost all family law litigation in British Columbia , Canada : the Provincial ( Family ) Court and the Supreme Court . Each court has its own rules , its own forms , and its own process .   There are two main laws that apply to family law problems in BC . A law , in this sense of the word , means a rule made by the government . These laws are the federal Divorce Act and the provincial Family Law Act . Each law deals with different issues , although they share a lot of issues in common . For some couples , both laws will apply ; for others , only one of these laws will apply , probably the Family Law Act .   You do n't have to go to court , no matter how bad your problem is . The only times you must go to court are when :  you need a divorce ,  someone is threatening to do something serious , like take the children away ,  there is a risk of violence ,  someone is threatening to hide property or money , or  you just ca n't agree about how to fix the problem no matter how hard you try .   If you do n't have to deal with one or more of these issues , you can always try to negotiate a way of fixing the problem , to find a solution that you both agree with . Couples who need help negotiating sometimes hire someone else to help , someone who is usually a stranger to them , called a mediator . Mediators help to guide the negotiation process and encourage people to see different ways of solving the problem .   Lawyers who mediate family law problems are called family law mediators , and have special training in mediation apart from their training as lawyers . Because there are no rules in British Columbia about who can and who ca n't call themselves a mediator , you should look carefully at the mediator 's credentials before you agree to use that person as your mediator .

negative: Lagrangian relaxation In the field of mathematical optimization , Lagrangian relaxation is a relaxation method which approximates a difficult problem of constrained optimization by a simpler problem . A solution to the relaxed problem is an approximate solution to the original problem , and provides useful information .   The method penalizes violations of inequality constraints using a Lagrange multiplier , which imposes a cost on violations . These added costs are used instead of the strict inequality constraints in the optimization . In practice , this relaxed problem can often be solved more easily than the original problem .   The problem of maximizing the Lagrangian function of the dual variables ( the Lagrangian multipliers ) is the Lagrangian dual problem .


query: IPCC were wrong about Amazon rainforests

positive: Amazon rainforest The Amazon rainforest ( Portuguese : Floresta Amazônica or Amazônia ; Selva Amazónica , Amazonía or usually Amazonia ; Forêt amazonienne Amazoneregenwoud ) , also known in English as Amazonia or the Amazon Jungle , is a moist broadleaf forest in the Amazon biome that covers most of the Amazon basin of South America . This basin encompasses 7,000,000 km2 , of which 5,500,000 km2 are covered by the rainforest . This region includes territory belonging to nine nations . The majority of the forest is contained within Brazil , with 60 % of the rainforest , followed by Peru with 13 % , Colombia with 10 % , and with minor amounts in Venezuela , Ecuador , Bolivia , Guyana , Suriname and French Guiana . States or departments in four nations contain `` Amazonas '' in their names . The Amazon represents over half of the planet 's remaining rainforests , and comprises the largest and most biodiverse tract of tropical rainforest in the world , with an estimated 390 billion individual trees divided into 16,000 species .

positive: Tropical rainforest Tropical rainforests occur in areas of tropical rainforest climate in which there is no dry season -- all months have an average precipitation of at least 60 mm -- and may also be referred to as lowland equatorial evergreen rainforest . True rainforests are typically found between 10 degrees north and south of the equator ( see map ) ; they are a sub-set of the tropical forest biome that occurs roughly within the 28 degree latitudes ( in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn ) . Within the World Wildlife Fund 's biome classification , tropical rainforests are a type of tropical moist broadleaf forest ( or tropical wet forest ) that also includes the more extensive tropical seasonal forests .

positive: Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries . The Amazon drainage basin covers an area of about 7,500,000 km2 , or roughly 40 percent of the South American continent . It is located in the countries of Bolivia , Brazil , Colombia , Ecuador , Guyana , Peru , Suriname and Venezuela .   Most of the basin is covered by the Amazon Rainforest , also known as Amazonia . With a 5500000 km2 area of dense tropical forest , this is the largest rainforest in the world .

positive: Deforestation Deforestation , clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use . Examples of deforestation include conversion of forestland to farms , ranches , or urban use . The most concentrated deforestation occurs in tropical rainforests . About 30 % of Earth 's land surface is covered by forests .   Deforestation occurs for multiple reasons : trees are cut down to be used for building or sold as fuel , ( sometimes in the form of charcoal or timber ) , while cleared land is used as pasture for livestock and plantation . The removal of trees without sufficient reforestation has resulted in damage to habitat , biodiversity loss and aridity . It has adverse impacts on biosequestration of atmospheric carbon dioxide . Deforestation has also been used in war to deprive the enemy of vital resources and cover for its forces . Modern examples of this were the use of Agent Orange by the British military in Malaya during the Malayan Emergency and the United States military in Vietnam during the Vietnam War . As of 2005 , net deforestation rates have ceased to increase in countries with a per capita GDP of at least US$ 4,600 . Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland .   Disregard of ascribed value , lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale . In many countries , deforestation , both naturally occurring and human-induced , is an ongoing issue . Deforestation causes extinction , changes to climatic conditions , desertification , and displacement of populations as observed by current conditions and in the past through the fossil record . More than half of all plant and land animal species in the world live in tropical forests .   Between 2000 and 2012 , 2.3 e6sqkm of forests around the world were cut down . As a result of deforestation , only 6.2 e6km2 remain of the original 16 e6km2 of forest that formerly covered the Earth .

negative: Peruvian Amazon The Peruvian Amazon ( Amazonía del Perú ) is the area of the Amazon rainforest included within the country of Peru , from east of the Andes to the borders with Ecuador , Colombia , Brazil and Bolivia . This region comprises 60 % of the country and is marked by a large degree of biodiversity . Peru has the second-largest portion of the Amazon rainforest after the Brazilian Amazon .

negative: Ectoedemia tabulosa Ectoedemia tabulosa is a moth of the Nepticulidae family . It is found in the lowland Amazon rainforest in Ecuador .   The wingspan is about 5.6 mm for males . Adults have been collected in January .

negative: Alto Maués Ecological Station Alto Maués Ecological Station ( Estação Ecológica Alto Maués ) is an ecological station , a fully protected area , in the state of Amazonas , Brazil . It contains about 6,656 km2 of Amazon rainforest .

negative: Tres Fronteras Tres Fronteras ( Três Fronteiras ) is the Spanish name for an area of the Amazon Rainforest in the Upper Amazon region of South America .

negative: Amazonian Amazonian may refer to :  Amazonian build , a female body shape  Amazonian ( Mars ) , a geologic system and time period on the planet Mars  Amazon River , in South America  Amazon basin , that river 's drainage basin  Amazon rainforest , rainforest covering most of the Amazon Basin  relating to the Amazons in Greek mythology  Amazonian , an employee of the company Amazon.com  Amazonian , a fictional species in the Futurama episode `` Amazon Women in the Mood ''

negative: Lake Rimachi Lake Rimachi ( Lago Rimachi in Spanish ) is a lake in northern Peru in the Amazon Rainforest of about 300 hectare of extension . It is located on the western banks of Pastaza River , being its main inflow source the Chapuli River , and its main outflow the Rimachi River . The lands around the lake were home to the Murato people , who are now extinct .

negative: Acalyptris amazonius Acalyptris amazonius is a moth of the Nepticulidae family . It is found in lowland Amazon rainforest in Ecuador .   The wingspan is 3.4-3 .5 mm for males and about 3.7 mm for females . Adults have been collected in January .

negative: Northern Amazon Ecological Corridor The Northern Amazon Ecological Corridor ( Corredor Norte da Amazônia ) is a proposed ecological corridor connecting conservation units and indigenous territories in the north of the Amazon rainforest of Brazil .

negative: South Amazon Ecological Corridor The South Amazon Ecological Corridor ( Corredor Sul da Amazônia ) is a proposed ecological corridor connecting conservation units and indigenous territories in the southeast of the Amazon rainforest of Brazil .

negative: Cyclophora difficilis Cyclophora difficilis is a moth in the family Geometridae . It is found in the Amazon rainforest .

negative: Amazon Souls Amazon Souls is a 2013 British documentary film directed , produced and presented by Sarah Begum . The film examines the impact of modernity on the culture of the Huaorani tribe in the Ecuadorian Amazon Rainforest .

negative: List of plants of the Amazon rainforest This is a list of plants found in the wild in Amazon Rainforest vegetation of Brazil . The estimates from useful plants suggested that there are 800 plant species of economic or social value in this forest ,  according to Giacometti ( 1990 ) . Additions are currently being made to this list .   Flora definition  Flora is the scientific word for plant .

negative: Amazon Region Protected Areas Program The Amazon Region Protected Areas Program ( ARPA ; Programa Áreas Protegidas da Amazônia ) is a joint initiative sponsored by government and non-government agencies to expand protection of the Amazon rainforest in Brazil .

negative: Euglossa bidentata Euglossa bidentata is a Euglossine bee species found in the Amazon rainforest .

negative: Wilson Pinheiro Wilson Pinheiro ( died in 1980 ) was the president of the Brasiléia Rural Workers Union in the State of Acre in Brazil . He helped lead the fight against ranchers who were destroying the Amazon Rainforest . Pinheiro was committed to defense of the Amazon and was assassinated on July 21 , 1980 . He was a colleague of Chico Mendes , the President of the Xapuri Rural Workers Union , who similarly lost his life defending the Amazon .

negative: Amazon natural region Amazonía region in southern Colombia comprises the departments of Amazonas , Caquetá , Guainía , Guaviare , Putumayo and Vaupés , and covers an area of 403,000 km ² , 35 % of Colombia 's total territory . The region is mostly covered by tropical rainforest , or jungle , which is a part of the massive Amazon rainforest .

negative: Amazonia (disambiguation) Amazonia refers to the Amazon rainforest . It may also refer to :

negative: Paracles juruana Paracles juruana is a moth of the Arctiidae family . It is found in Amazon rainforest of Brazil .

negative: Fauna of Nicaragua The fauna of Nicaragua is characterized by a very high level of biodiversity . Much of Nicaragua 's wildlife lives in protected areas . There are currently 78 protected areas in Nicaragua , covering more than 22000 km2 , or about 17 % of its landmass .   These protected areas encompass a wide variety of habitats , including rainforests , lakes , mountains , and volcanoes throughout the country . For example , Bosawás Biosphere Reserve in state of Jinotega ( border with Honduras ) , covers 7300 km2 , making it the second largest rainforest in the Americas after the Amazon Rainforest in Brazil .

negative: Tupi people The Tupi people were one of the most important indigenous peoples in Brazil . Scholars believe they first settled in the Amazon rainforest , but 2900 years ago they started to spread southward and gradually occupied the Atlantic coast .

negative: Ucayali moist forests The Napo moist forests ( NT0174 ) is an ecoregion in the western Amazon rainforest of Peru .

negative: Amazon Theatre The Amazon Theatre is an opera house located in Manaus , in the heart of the Amazon rainforest in Brazil . It is the location of the annual Festival Amazonas de Ópera ( Amazonas Opera Festival ) and the home of the Amazonas Philharmonic Orchestra which regularly rehearses and performs at the Amazon Theater along with choirs , musical concerts and other performances .

negative: Paracles laboulbeni Paracles laboulbeni is a moth of the Arctiidae family . It is found in Surinam and Amazon rainforest .

negative: Atalaya Province Atalaya is the largest of four provinces in the Ucayali Region , in the central Amazon rainforest of Peru .

negative: Dysoptus fasciatus Dysoptus fasciatus is a species of moth in the Arrhenophanidae family . It probably has a wide distribution in the lowland Amazon rainforest . Currently it has been collected only at the type locality in southern Venezuela and possibly in Peru .   The length of the forewings is about 4.1 mm for males and about 9.1 for females . Adults are on wing in early February .

negative: Ananteris pydanieli Ananteris pydanieli is a species of scorpion from the Brazilian Amazon rainforest . It is a member of the Buthidae family .

negative: Hypsiboas nympha Hypsiboas nympha is a species of frog in the family Hylidae . It is endemic to the Amazon Rainforest .

negative: Sinchi Amazonic Institute of Scientific Research The Sinchi Amazonic Institute of Scientific Research ( Instituto Amazónico de Investigaciones Científicas ) is a non-profit research institute of the Government of Colombia charged with carrying out scientific investigations on matters relating to the Amazon Rainforest , the Amazon River and the Amazon Region of Colombia for its better understanding and protection . The word sinchi , is a word in Quechua that means `` strong '' or `` fierce '' .

negative: Napo moist forests The Napo moist forests ( NT0142 ) is an ecoregion in the western Amazon rainforest of Colombia , Ecuador and Peru .

negative: Cryptocellus becki Cryptocellus becki is an arachnid species in the genus Cryptocellus . It can be found in the Amazon rainforest .

negative: M. africana M. africana may refer to :  Malcolmia africana , the African mustard , a plant species  Mirafra africana , the rufous-naped lark , a bird species  Mustela africana , the Amazon weasel or Tropical Weasel , a weasel species found in the Amazon Rainforest in Brazil

negative: Eastern Amazon climbing mouse The eastern Amazon climbing mouse , Rhipidomys emiliae , is a rodent species from South America . It is endemic to central Brazil , where it is found in the eastern fringe of the Amazon rainforest , as well as in gallery forest and tropical dry forest within the cerrado ecoregion . It is often found in areas under cultivation .


query: Worst-case global heating scenarios may need to be revised upwards in light of a better understanding of the role of clouds, scientists have said.

positive: Clouds and the Earth's Radiant Energy System Clouds and the Earth 's Radiant Energy System ( CERES ) is NASA climatological experiment from Earth orbit .  The CERES are scientific satellite instruments , part of the NASA 's Earth Observing System  ( EOS ) , designed to measure both solar-reflected and Earth-emitted radiation from the top of the atmosphere ( TOA ) to the  Earth 's surface . Cloud properties are determined using simultaneous measurements by other EOS instruments such as the  Moderate Resolution Imaging Spectroradiometer ( MODIS ) . Results from the CERES and other NASA missions , such as the Earth Radiation Budget Experiment ( ERBE ) ,  could lead to a better understanding of the role of clouds and the energy cycle in global climate change .

positive: Cloud In meteorology , a cloud is an aerosol comprising a visible mass of minute liquid droplets , frozen crystals , or particles suspended in the atmosphere above the surface of a planetary body . The droplets and crystals may be made of water or various chemicals . On Earth , clouds are formed as a result of saturation of the air when it is cooled to its dew point , or when it gains sufficient moisture ( usually in the form of water vapor ) from an adjacent source to raise the dew point to the ambient temperature . They are seen in the Earth 's homosphere ( which includes the troposphere , stratosphere , and mesosphere ) . Nephology is the science of clouds which is undertaken in the cloud physics branch of meteorology .   There are two systems of naming clouds in their respective layers of the atmosphere ; Latin in the troposphere and mostly alpha-numeric above the troposphere . Cloud types in the troposphere , the atmospheric layer closest to Earth 's surface , have Latin names due to the universal adaptation of Luke Howard 's nomenclature . Formally proposed in 1802 , it became the basis of a modern international system that classifies clouds into five physical forms and three altitude levels ( formerly known as étages ) . These physical types , in approximate ascending order of convective activity , include stratiform sheets , cirriform wisps and patches , stratocumuliform layers ( mainly structured as rolls , ripples , and patches ) , cumuliform heaps , and very large cumulonimbiform heaps that often show complex structure . The physical forms are cross-classified by the altitude levels to produce ten basic genus-types , most of which can be divided into species , and subdivided into varieties .   Two cirriform clouds that form higher up in the stratosphere and mesosphere have common names for their main types , but are sub-classified alpha-numerically . They are relatively uncommon and are mostly seen in the polar regions of Earth . Clouds have been observed in the atmospheres of other planets and moons in the Solar System and beyond . However , due to their different temperature characteristics , they are often composed of other substances such as methane , ammonia , and sulfuric acid as well as water .   Homospheric types determined by cross-classification of forms and levels .   '' Homospheric types include the ten tropospheric genera and two additional major types above the troposphere . The cumulus genus includes three variants as defined by vertical size .

positive: Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .

negative: Worst Case Scenario (song) `` Worst Case Scenario '' is the third single by the English indie band The Hoosiers from their 2007 # 1 album The Trick to Life . It has been admitted by lead man Irwin on the band 's website that it is one of the band 's favourite songs .

negative: Worst-Case Scenario series Worst-Case Scenario is the name of a series of merchandise based on a 1999 book written by Joshua Piven and David Borgenicht and published by Chronicle Books . The series first entry , The Worst-Case Scenario Survival Handbook , sold over 10 million copies worldwide and prompted a series of related books , games , calendars , and two television series . Later works have been published via Quirk Books and has been credited with giving the company enough funding to expand .

negative: Worst-case scenario (disambiguation) Worst-case scenario may refer to :  Worst Case Scenario ( album ) , by dEUS  `` Worst Case Scenario '' ( song ) , by The Hoosiers  Worst Case Scenario ( Star Trek : Voyager )  Worst-Case Scenario series , series of books inspired by The Worst-Case Scenario Survival Handbook  Worst Case Scenarios , a reality show aired on TBS in 2002 in the U.S.  Worst Case Scenario ( film ) , a Dutch horror film  Worst Case Scenario Records , a UK record label  Worst-Case Scenario ( TV series ) , a survival show hosted by Bear Grylls aired on Discovery Channel in 2010

negative: Ceiling projector The ceiling projector or cloud searchlight is used to measure the height of the base of clouds ( called the ceiling ) above the ground . It is used in conjunction with an alidade , usually positioned 1000 ft ( 304.8 m ) away and wherever possible set at the same level .   The projector is normally set at 90 ° , although 71 ° 31 ' may be used , in relation to the terrain . The projector consists of a 430 W incandescent bulb set in a weatherproof housing . Inside the housing are two mirrors ; the first , above the bulb , reflects the light downwards to the second mirror , that then reflects the light upwards to the cloud . Both mirrors are focused to produce a high intensity beam of light that renders a visible spot on the base of the cloud .   The alidade is mounted on a post at a height of 5 ft ( 1.524 m ) from the ground . It consists of an arm with a pointer and open sight at one end and a rubber eyepiece at the other . The arm is mounted onto a curved scale that is marked both in meters and the coded cloud height ( feet ) . The observer looks through the eyepiece and sets the sight onto the spot projected on the cloud and reads the height from the attached scale .   When the cloud is thin the beam of light may penetrate into the cloud . The observer should read the scale where the light first enters the cloud and not at the top . However , a remark may be made as to how far into the cloud the light was able to penetrate as this may be useful . In the case of fog or blizzard conditions the observer should read the scale where the beam disappears .

negative: The Best Worst-Case Scenario The Best Worst-Case Scenario is the first album released by Tooth & Nail Records alternative rock band Fair , which features notable musician and record producer Aaron Sprinkle . The album was released on June 6 , 2006 .   In 2007 , the album artwork , designed by Invisible Creature was nominated for a Grammy Award for Best Recording Packaging .

negative: Worst Case Scenario (film) Worst Case Scenario was a horror film to be directed by Dutch director Richard Raaphorst .

negative: Worst Case Scenario (Star Trek: Voyager) __ NOTOC __  `` Worst Case Scenario '' is the 67th series and 25th and penultimate episode of the third season of Star Trek : Voyager .

negative: Best, worst and average case In computer science , best , worst , and average cases of a given algorithm express what the resource usage is at least , at most and on average , respectively . Usually the resource being considered is running time , i.e. time complexity , but it could also be memory or other resource .   In real-time computing , the worst-case execution time is often of particular concern since it is important to know how much time might be needed in the worst case to guarantee that the algorithm will always finish on time .   Average performance and worst-case performance are the most used in algorithm analysis . Less widely found is best-case performance , but it does have uses : for example , where the best cases of individual tasks are known , they can be used to improve the accuracy of an overall worst-case analysis . Computer scientists use probabilistic analysis techniques , especially expected value , to determine expected running times .   The terms are used in other contexts ; for example the worst - and best-case outcome of a planned-for epidemic , worst-case temperature to which an electronic circuit element is exposed , etc. . Where components of specified tolerance are used , devices must be designed to work properly with the worst-case combination of tolerances and external conditions .

negative: Smoothed analysis Smoothed analysis is a way of measuring the complexity of an algorithm . It gives a more realistic analysis of the practical performance of the algorithm , such as its running time , than using worst-case or average-case scenarios .

negative: Inter-American Institute for Global Change Research The Inter-American Institute for Global Change Research , IAI , is an intergovernmental organization supported by 19 countries in the Americas , dedicated to pursuing the principles of scientific excellence , international cooperation , and the full and open exchange of scientific information to increase the understanding of global change phenomena and their socio-economic implications .   Recognizing the need to better understand the natural and social processes which drive large scale environmental change , the IAI encourages interactive exchanges between scientists and policy makers . The goal of the IAI is to augment the scientific capacity in the region and to provide information to policy makers in a useful and timely manner . Its primary objective is to encourage research beyond the scope of national programs , by advancing comparative and focused studies based on scientific issues important to the region as a whole .

negative: Petro-sexual politics Petro-sexual politics is a lens used to better understand the relationships between petroleum and gender violence and the role colonial powers possess . The underlying theme of petro-sexual politics is that gender violence is part of a larger political economy of violence . Petro-sexual politics can yield new methods of theorizing global politics , particularly as explained here for the Nigerian case of the `` natural resource curse '' .

negative: Discounted maximum loss Discounted maximum loss , also known as worst-case risk measure , is the present value of the worst-case scenario for a financial portfolio .   In investment , in order to protect the value of an investment , one must consider all possible alternatives to the initial investment . How one does this comes down to personal preference ; however , the worst possible alternative is generally considered to be the benchmark against which all other options are measured . The present value of this worst possible outcome is the discounted maximum loss .

negative: World Values Survey The World Values Survey ( WVS ) is a global research project that explores people 's values and beliefs , how they change over time and what social and political impact they have . It is carried out by a worldwide network of social scientists who , since 1981 , have conducted representative national surveys in almost 100 countries .   The WVS measures , monitors and analyzes : support for democracy , tolerance of foreigners and ethnic minorities , support for gender equality , the role of religion and changing levels of religiosity , the impact of globalization , attitudes toward the environment , work , family , politics , national identity , culture , diversity , insecurity , and subjective well-being .   The findings provide information for policy makers seeking to build civil society and democratic institutions in developing countries . The work is also frequently used by governments around the world , scholars , students , journalists and international organizations and institutions such as the World Bank and the United Nations ( UNDP and UN-Habitat ) . Data from the World Values Survey have for example been used to better understand the motivations behind events such as the Arab Spring , the 2005 French civil unrest , the Rwandan genocide in 1994 and the Yugoslav wars and political upheaval in the 1990s .   Romano Prodi , former Prime Minister of Italy and the tenth President of European Commission said about the WVS work :  The growing globalization of the world makes it increasingly important to understand -LSB- ... -RSB- diversity . People with varying beliefs and values can live together and work together productively , but for this to happen it is crucial to understand and appreciate their distinctive worldviews .

negative: Worst Case Scenario (album) Worst Case Scenario is the debut studio album by Belgian rock band Deus released in 1994 . The cover art was designed by guitarist Rudy Trouvé . It contains the single `` Suds & Soda '' , which became an underground hit and a fans favorite .   The album was first released in Belgium on the indie label Bang ! with a different track listing : `` Right as Rain '' and `` Great American Nude '' ( both tracks present on the Zea EP released in Belgium in 1993 ) are replaced by the song `` Let Go '' . It was then released in the UK and Europe through Island Records with the track listing as written below .   The song `` W.C.S. ( First Draft ) '' contains a covered bit from Frank Zappa 's `` Little Umbrellas '' , from his 1969 album , Hot Rats.Worst Case Scenario received good reviews internationally despite the hard time that the British media had to categorize its music into a genre . They finally called it Art rock ( a definition which still bothers singer Tom Barman ) . Worst Case Scenario reached Gold in Belgium , selling 30,000 copies . By April 2008 , WCS '' had sold 270,000 copies worldwide .

negative: Surviving Disaster (TV series) Surviving Disaster was a simulation of real life disaster situations produced by Spike . Hosted by former Navy SEAL Cade Courtley , each episode retells situations in a worst-case scenario and what viewers can do to survive them . There have been ten episodes aired to date . The series was not picked up for a second season .

negative: Summer draft Summer draft is a naval term for the worst-case loaded draft a ship can have . This draft is corrected for the worst-case seasonal conditions ( summer in this case ) . During summer the water is warmer , and thus less dense and expands slightly : see Thermal expansion . This makes ships float deeper in the water . Summer draft is the opposite of Light ship condition .

negative: Timeline of heat engine technology This Timeline of heat engine technology describes how heat engines have been known since antiquity but have been made into increasingly useful devices since the 17th century as a better understanding of the processes involved was gained . They continue to be developed today .   In engineering and thermodynamics , a heat engine performs the conversion of heat energy to mechanical work by exploiting the temperature gradient between a hot `` source '' and a cold `` sink '' . Heat is transferred to the sink from the source , and in this process some of the heat is converted into work .   A heat pump is a heat engine run in reverse . Work is used to create a heat differential . The timeline includes devices classed as both engines and pumps , as well as identifying significant leaps in human understanding .

negative: Scenario paintball Scenario paintball is a type of paintball game in which players participate in a scenario , or story ; and may include historical re-enactments , futuristic or video game simulations . Games tend to last in the range of hours or days , and may include a large group of players . The largest paintball scenario games are the Skirmish Invasion of Normandy ( ION ) scenario & Oklahoma D-DAY , both of which attract upwards of 4,000 players annually .   Scenario games are almost always objective-driven in regard to scoring . Each team must complete a series of missions to score points . These may be simple `` capture the flag at this location '' missions to elaborate missions involving props , multiple locations , interactive non-player characters and more .   To further enhance the theme of a game , field locations may be named for important story locations , and props of various sorts are added to the game . These may be objects that players collect for points , or even vehicles that take part in the fighting , like paintball tanks . Players may don costumes specific to the theme , such as historic military uniforms or other costumes .   Scenario events are usually planned far in advance , both by the event `` producers '' or fields , and by the players themselves . Players may form large , lasting networks of players and teams that play together year after year in a specific scenario . These organizations help plan game strategy and direct their groups on the field and offer a level of organization beyond the basic two-sided team play .   Like all forms of paintball , scenario paintball has a very good per-capita safety record . Due to longer play times , heat-related injuries are one of the more common injuries in scenario paintball . Many players often carry 1 - to 3-liter water bladders , allowing players to drink water without removing their safety masks , to combat heat and dehydration .

negative: Decatastrophizing In cognitive therapy , decatastrophizing or decatastrophization is a cognitive restructuring technique to treat cognitive distortions , such as magnification and catastrophizing , commonly seen in psychological disorders like anxiety and psychosis .   The technique consists of confronting the worst-case scenario of a feared event or object , using mental imagery to examine whether the effects of the event or object have been overestimated ( magnified or exaggerated ) and where the patient 's coping skills have been underestimated . The term was coined by Albert Ellis , and various versions of the technique have been developed , most notably by Aaron T. Beck .   Decatastrophizing is also called the `` what if '' technique , because the worst-case scenario is confronted by asking : `` What if the feared event or object happened , what would occur then ? ''   The following is an example :  `` I could make an absolute fool of myself if I say the wrong thing . ''  `` What if you say the wrong thing , what would happen then ? ''  `` He might think I 'm weird . '' ...

negative: Design methods Design methods is a broad area that focuses on :   Divergence -- Exploring possibilities and constraints of inherited situations by applying critical thinking through qualitative and quantitative research methods to create new understanding ( problem space ) toward better design solutions  Transformation -- Redefining specifications of design solutions which can lead to better guidelines for traditional and contemporary design activities ( architecture , graphic , industrial , information , interaction , et al. ) and/or multidisciplinary response  Convergence -- Prototyping possible scenarios for better design solutions that incrementally or significantly improve the originally inherited situation  Sustainability -- Managing the process of exploring , redefining and prototyping of design solutions continually over time  Articulation - the visual relationship between the parts and the whole .   The role of design methods is to support design work , the aims of which can be varied , though they may include gaining key insights or unique essential truths resulting in more holistic solutions in order to achieve better experiences for users with products , services , environments and systems they rely upon . Insight , in this case , is clear and deep investigation of a situation through design methods , thereby grasping the inner nature of things intuitively .

negative: Graphical timeline from Big Bang to Heat Death This is the timeline of the Universe from Big Bang to Heat Death scenario . The different eras of the universe are shown . The heat death will occur in 10103 years , if protons decay .   Usually the logarithmic scale is used for such timelines but it compresses the most interesting Stelliferous Era too much as this example shows . Therefore , a double-logarithmic scale s ( s * 100 in the graphics ) is used instead . The minimum of it is unfortunately only 1 , not 0 as needed , and the negative outputs for inputs smaller than 10 are useless . Therefore , the time from 0.1 to 10 years is collapsed to a single point 0 , but that does n't matter in this case because nothing special happens in the history of the universe during that time .     The seconds in the timescale have been converted to years by using the Julian year .

negative: Heat lightning Heat lightning , sometimes known as silent lightning , is the name used for the faint flashes of lightning on the horizon or other clouds from distant thunderstorms that do not have accompanying sounds of thunder . This often occurs because of inter-cloud and intra-cloud lightning , where lightning charges travel from cloud-to-cloud or merely areas of differing electric potential within a single cloud , respectively . Because of this nature , heat lightning can often be seen from great distances , and thus can be an early warning sign that thunderstorms are approaching . The term could be considered a misnomer because it has nothing to do with the heat of the lightning itself .   Heat lightning can also occur if cloud-to-ground lightning occurs very far away and the sound dissipates before it reaches the observer . At night , it is possible to see the flashes of lightning from very far distances , up to 100 miles , but the sound does not carry that far . In Florida , heat lightning is often seen over the water at night , the remnants of storms that formed during the day along a sea breeze front coming in from the opposite coast .   Heat lightning also occurs where airborne matter muffles the thunder , such as heavy snow in winter storms ( thundersnow ) and dust and sand storms . In some instances , heavy falling snow has silenced thunder from cloud to ground lightning strikes as close as one to two miles ( 1.6 to 3.2 km ) from the observer and severe dust storms are even more effective in many cases .   Heat lightning is not to be confused with electrically-induced luminosity actually generated at mesospheric altitudes above thunderstorm systems ( and likewise visible at exceedingly great ranges ) , a phenomenon known as `` sprites '' .

negative: CYK algorithm In computer science , the Cocke -- Younger -- Kasami algorithm ( alternatively called CYK , or CKY ) is a parsing algorithm for context-free grammars , named after its inventors , John Cocke , Daniel Younger and Tadao Kasami . It employs bottom-up parsing and dynamic programming .   The standard version of CYK operates only on context-free grammars given in Chomsky normal form ( CNF ) . However any context-free grammar may be transformed to a CNF grammar expressing the same language .   The importance of the CYK algorithm stems from its high efficiency in certain situations . Using Landau symbols , the worst case running time of CYK is Ο , where n is the length of the parsed string and | G | is the size of the CNF grammar G . This makes it one of the most efficient parsing algorithms in terms of worst-case asymptotic complexity , although other algorithms exist with better average running time in many practical scenarios .

negative: List of music considered the worst The list of music considered the worst consists of albums or songs that have been considered the worst music ever made by various combinations of music critics , television broadcasters ( such as MTV ) , radio stations , composers , and public polls . A piece of music needs to have been notable , popular , or memorable to be deemed the `` worst ever '' , or it would be unlikely to top all-time public polls a few years after it was released . As such , a piece usually needs to have had a high profile at the time of its release , such as an unexpected hit that was highly disliked outside of its fanbase . Scholarly accounts of the `` worst music ever '' are rare . Most polls or critical lists are light-hearted in nature , especially in pop music . Magazines reflect the preferences of their readers , and if polls are influenced by too small a group of readers or critics , they provide unreliable results . Most `` worst ever '' lists do not aim to take into account all music ever created , but are limited to certain time periods , styles of music , and geographical areas . Furthermore , individual tastes can vary widely , to the point where very little consensus on a worst song can be achieved ; the winning song in a CNN e-mail poll received less than 5 percent of the total votes cast . There are a handful of scholars who have done more in-depth analysis of music perceived to be bad , including Irwin Chusid , Barry Hansen ( better known by the stage name Dr. Demento ) and Darryl W. Bullock , author of the 2013 book The World 's Worst Records .

negative: 2002 India heat wave More than 1,030 people were killed in the 2002 heatwave in south India . Most of the dead were poor and elderly and a majority of deaths occurred in the southern state of Andhra Pradesh . In districts that were impacted most , the heat was so severe that ponds and rivers evaporated and in those same districts birds had fallen from the sky and animals were collapsing from the intense heat . It is said by officials to be the worst heat wave in four years . The relief commissioner of Andhra Pradesh , Rosaiah , said that the maximum number of 172 deaths related to heat took place in the East Godavari district . There were also 166 deaths in Prakasam and 144 deaths in West Godavari . Unusually high temperatures were detected across India during April of the year 2002 . In addition , this heat wave over northern zones of India lasted from the middle of April to the third week in May , thus , causing these fatalities . On May 10 the highest temperature recorded in the region of Gannavaram ( Vijayawada ) was 49 degrees Celsius ( 120.2 degrees Fahrenheit ) . According to the BBC News , `` Heatwaves are defined as periods of abnormally high temperatures and usually occur between March and June in India . May is the country 's hottest month , with an average maximum temperature of 41C ( 104F ) in Delhi . Longer , more severe heatwaves are becoming increasingly frequent globally . Intense heat can cause cramps , exhaustion and heat stroke . Thousands of people have died across India during heatwaves in 2002 and 2003 . '' The heatwaves also affected the northern states of Punjab , Haryana , Orissa and 100 people suffered from heat-related sickness .  2010 Indian heatwave

negative: Addictive personality An addictive personality refers to a particular set of personality traits that make an individual predisposed to developing addictions . This hypothesis states that there are common elements among people with varying addictions that relates to personality traits . People who are substance dependent are characterized by : a physical or psychological dependency that negatively affects their quality of life . They are frequently connected with substance abuse ; however , people with addictive personalities are also highly at risk of becoming addicted to gambling , food , pornography , exercise , work , and codependency . Scientists have been better able to understand addictive personalities as researchers delve further into understanding the chemistry of addiction . Alan R. Lang of Florida State University , author of an addiction study prepared for the United States National Academy of Sciences , said , `` If we can better identify the personality factors , they can help us devise better treatment and can open up new strategies to intervene and break the patterns of addiction . ''

negative: Perfect Disaster Perfect Disaster was a one-hour American documentary television mini-series that premiered in 2006 on the Discovery Channel . The program depicted the worst-case scenario that major cities could expect in the near future if hit by extreme disaster . A large part of each episode was recounted the lives of citizens from each city , with the remainder of the program showing us real-world scientists discussing the very high probabilities of these disasters . The trademark tagline of the show was `` When the conditions are right , it will all go wrong . '' The series currently airs on the Science Channel .

negative: Water sky Water sky is a phenomenon that is closely related to ice blink . It forms in regions with large areas of ice and low-lying clouds and so is limited mostly to the extreme northern and southern sections of earth , in Antarctica and in the Arctic .   When light hits the blue oceans or seas , some of it bounces back and enables the observer to physically see the water . However , some of the light also is reflected back up on to the bottoms of low-lying clouds and causes a dark spot to appear underneath some clouds . These clouds may be visible when the seas are not and can show alert and knowledgeable travelers the general direction of water . The dark clouds over open water have long been used by polar explorers and scientists to navigate in sea ice . For example , Arctic explorer Fridtjof Nansen and his assistant Hjalmar Johansen used the phenomenon to find lanes of water in their failed expedition to the North Pole as did Bernacchi and Sir Douglas Mawson in the Antarctica .

negative: Downhole safety valve A downhole safety valve refers to a component on an oil and gas well , which acts as a failsafe to prevent the uncontrolled release of reservoir fluids in the event of a worst-case-scenario surface disaster . It is almost always installed as a vital component on the completion .

negative: Flight interception trap The Flight Interception Trap or FIT is a widely used trapping system for flying insects . It is especially well-suited for collecting beetles , since these animals usually drop themselves after flying into an object , rather than flying upward ( in which case a Malaise trap is a better option ) . Flight Interception Traps are mainly used to collect flying species which are not likely to be attracted to bait or light .

negative: Cirrus spissatus cloud Cirrus spissatus clouds are the highest of the main cloud genera , and may sometimes even occur in the lower stratosphere . The characteristic features of cirrus clouds are fine threads or wisps of ice crystals , generally white , but appearing grey when dense and seen against the light . There is no precipitation at the ground . It also frequently exhibits optical phenomena .   Cirrus spissatus is the dense cirrus that will partly or completely hide the sun ( or moon ) and which appears dark grey when seen against the light . Although it arises under various circumstances , it is particularly commonly found in the plumes or anvils of cumulonimbus clouds .   Precipitation is likely within 15 to 25 hours if winds are steady from NE E to S , or sooner if winds SE to S . Other winds bring an overcast sky .   A different variety of cirrus spissatus also forms from phenomena that have nothing to do with cumulonimbus blow-off or dissipating cumulonimbus cells -LSB- citation needed -RSB- . When dense cirrus is formed by means other than by cumulonimbus blow-off or dissipating cumulonimbus clouds , it will frequently be seen as many dense patches at different levels ( cirrus spissatus duplicatus ) , often mixed with thin cirrus filaments -LSB- citation needed -RSB- . Another variety , cirrus spissatus intortus , is sometimes described as looking like `` entangled sheaves '' of cirrus clouds . When viewed toward the sun , the denser patches often have gray bases .

negative: Ticking time bomb scenario The ticking time bomb scenario is a thought experiment that has been used in the ethics debate over whether torture can ever be justified . As a thought experiment , there is no need that the scenario be plausible ; it need only serve to highlight ethical considerations . The scenario can be formulated as follows :   Suppose that a person with knowledge of an imminent terrorist attack , that will kill many people , is in the hands of the authorities and that he will disclose the information needed to prevent the attack only if he is tortured . Should he be tortured ?   The scenario can be better understood through the arguments of those who respond to it ; the consequentialist argument is that nations , even those that legally disallow torture , can justify its use if they have a terrorist in custody who possesses critical knowledge , such as the location of a time bomb or a weapon of mass destruction that will soon explode and cause great loss of life . Opponents to the argument usually begin by exposing certain assumptions that tend to be hidden by initial presentations of the scenario and tend to obscure the true costs of permitting torture in `` real-life '' scenarios -- e.g. , the assumption that the person is in fact a terrorist , whereas in real life there usually remains uncertainty about whether the person is in fact a terrorist and that he has useful information -- and rely on legal , philosophical/moral , and empirical grounds to reaffirm the need for the absolute prohibition of torture . There is also uncertainty about the effectiveness of torture , and much opposition to torture is based on the fact it is not effective rather than any moral issue .