A search engine is an information retrieval system designed to help find information stored on a computer system. Search engines help to minimize the time required to find information and the amount of information which must be consulted, akin to other techniques for managing information overload.[citation needed]
The most public, visible form of a search engine is a Web search engine which searches for information on the World Wide Web.
How search engines work
Search engines provide an interface to a group of items that enables users to specify criteria about an item of interest and have the engine find the matching items. The criteria are referred to as a search query. In the case of text search engines, the search query is typically expressed as a set of words that identify the desired concept that one or more documents may contain[1]. There are several styles of search query syntax that vary in strictness. It can also switch names within the search engines from previous sites. Whereas some text search engines require users to enter two or three words separated by white space, other search engines may enable users to specify entire documents, pictures, sounds, and various forms of natural language. Some search engines apply improvements to search queries to increase the likelihood of providing a quality set of items through a process known as query expansion.
index-based search engine
The list of items that meet the criteria specified by the query is typically sorted, or ranked. Ranking items by relevance (from highest to lowest) reduces the time required to find the desired information. Probabilistic search engines rank items based on measures of similarity (between each item and the query, typically on a scale of 1 to 0, 1 being most similar) and sometimes popularity or authority (see Bibliometrics) or use relevance feedback. Boolean search engines typically only return items which match exactly without regard to order, although the term boolean search engine may simply refer to the use of boolean-style syntax (the use of operators AND, OR, NOT, and XOR) in a probabilistic context.
To provide a set of matching items that are sorted according to some criteria quickly, a search engine will typically collect metadata about the group of items under consideration beforehand through a process referred to as indexing. The index typically requires a smaller amount of computer storage, which is why some search engines only store the indexed information and not the full content of each item, and instead provide a method of navigating to the items in the search engine result page. Alternatively, the search engine may store a copy of each item in a cache so that users can see the state of the item at the time it was indexed or for archive purposes or to make repetitive processes work more efficiently and quickly.
Other types of search engines do not store an index. Crawler, or spider type search engines (a.k.a. real-time search engines) may collect and assess items at the time of the search query, dynamically considering additional items based on the contents of a starting item (known as a seed, or seed URL in the case of an Internet crawler). Meta search engines store neither an index nor a cache and instead simply reuse the index or results of one or more other search engines to provide an aggregated, final set of results.
http://en.wikipedia.org/wiki/Search_engine_(computing)
วันจันทร์ที่ 24 พฤศจิกายน พ.ศ. 2551
Rubric
A rubric is a word or section of text which is written or printed in red ink to highlight it. The term derives from the Latin: rubrica, meaning red ochre or red chalk,[1] and originates in Medieval illuminated manuscripts from the 13th century or earlier. In these, red letters were used to highlight initial capitals (particularly of psalms), section headings and names of religious significance, a practice known as rubrication, which was a separate stage in the production of a manuscript.
Rubric can also mean the red ink or paint used to make rubrics, or the pigment used to make it.[2] Although red was most often used, other colours came into use from the late Middle Ages onwards, and the word rubric was used for these also.
http://en.wikipedia.org/wiki/Rubric
Rubric can also mean the red ink or paint used to make rubrics, or the pigment used to make it.[2] Although red was most often used, other colours came into use from the late Middle Ages onwards, and the word rubric was used for these also.
http://en.wikipedia.org/wiki/Rubric
Knowledge management
Knowledge Management (KM) comprises a range of practices used in an organisation to identify, create, represent, distribute and enable adoption of insights and experiences. Such insights and experiences comprise knowledge, either embodied in individuals or embedded in organisational processes or practice. An established discipline since 1995, KM includes courses taught in the fields of business administration, information systems, management, and library and information sciences [1]. More recently, other fields, to include those focused on information and media, computer science, public health, and public policy, also have started contributing to KM research. Many large companies and non-profit organisations have resources dedicated to internal KM efforts, often as a part of their 'Business Strategy', 'Information Technology', or 'Human Resource Management' departments [2]. Several consulting companies also exist that provide strategy and advice regarding KM to these organisations.
KM efforts typically focus on organisational objectives such as improved performance, competitive advantage, innovation, the sharing of lessons learned, and continuous improvement of the organisation. KM efforts overlap with Organisational Learning, and may be distinguished from by a greater focus on the management of knowledge as a strategic asset and a focus on encouraging the exchange of knowledge. KM efforts can help individuals and groups to share valuable organisational insights, to reduce redundant work, to avoid reinventing the wheel per se, to reduce training time for new employees, to retain intellectual capital as employees turnover in an organisation, and to adapt to changing environments and markets
http://en.wikipedia.org/wiki/Knowledge_management
KM efforts typically focus on organisational objectives such as improved performance, competitive advantage, innovation, the sharing of lessons learned, and continuous improvement of the organisation. KM efforts overlap with Organisational Learning, and may be distinguished from by a greater focus on the management of knowledge as a strategic asset and a focus on encouraging the exchange of knowledge. KM efforts can help individuals and groups to share valuable organisational insights, to reduce redundant work, to avoid reinventing the wheel per se, to reduce training time for new employees, to retain intellectual capital as employees turnover in an organisation, and to adapt to changing environments and markets
http://en.wikipedia.org/wiki/Knowledge_management
Copy Right & Fair Use
Copyright is a legal concept, enacted by governments, giving the creator of an original work of authorship exclusive rights to control its distribution for a certain time period, after which the work enters the public domain. Generally, it is "the right to copy", but usually provides the author with other rights as well, such as the right to be credited for the work, to determine who may adapt the work to other forms, who may perform the work, who may financially benefit from it, and other, related rights. It is an intellectual property form (like the patent, the trademark, and the trade secret) applicable to any expressible form of an idea or information that is substantive and discrete. Copyright was initially conceived as a way for governments in Europe to restrict printing; the contemporary intent of copyright is to promote the creation of new works by giving authors control of and profit from them.
Copyright has been internationally standardized, lasting between fifty to a hundred years from the author's death, or a finite period for anonymous or corporate authorship; some jurisdictions have required formalities to establishing copyright, most recognize copyright in any completed work, without formal registration. Generally, copyright is enforced as a civil matter, though some jurisdictions do apply criminal sanctions.
Most jurisdictions recognize copyright limitations, allowing "fair" exceptions to the author's exclusivity of copyright, and giving users certain rights. The development of the Internet, digital media, computer network technologies, such as peer-to-peer filesharing, have prompted reinterpretation of these exceptions, introduced new difficulties in enforcing copyright, and inspired additional challenges to copyright law's philosophic basis. Simultaneously, businesses with great economic dependence upon copyright have advocated the extension and expansion of their copy rights, and sought additional legal and technological enforcement.
http://en.wikipedia.org/wiki/Copyrights
Fair use
Fair use is a doctrine in United States copyright law that allows limited use of copyrighted material without requiring permission from the rights holders, such as use for scholarship or review. It provides for the legal, non-licensed citation or incorporation of copyrighted material in another author's work under a four-factor balancing test. The term "fair use" originated in the United States, but has been added to Israeli and the UK law as well; a similar principle, fair dealing, exists in some other common law jurisdictions. Civil law jurisdictions have other limitations and exceptions to copyright.
วันจันทร์ที่ 10 พฤศจิกายน พ.ศ. 2551
Information system
Information systems
The term information system (IS) sometimes refers to a system of persons, data records and activities that process the data and information in an organization, and it includes the organization's manual and automated processes. Computer-based information systems are the field of study for information technology, elements of which are sometimes called an "information system" as well, a usage some consider to be incorrect.
History of information systems
The study of information systems originated as a sub-discipline of computer science in an attempt to understand and rationalize the management of technology within organizations. It has matured into a major field of management, that is increasingly being emphasized as an important area of research in management studies, and is taught at all major universities and business schools in the world. Börje Langefors introduced the concept of "Information Systems" at the third International Conference on Information Processing and Computer Science in New York in 1965.
Information technology is a very important malleable resource available to executives.Many companies have created a position of Chief Information Officer (CIO) that sits on the executive board with the Chief Executive Officer (CEO), Chief Financial Officer (CFO), Chief Operating Officer (COO) and Chief Technical Officer (CTO).The CTO may also serve as CIO, and vice versa.
Information technology is a very important malleable resource available to executives.Many companies have created a position of Chief Information Officer (CIO) that sits on the executive board with the Chief Executive Officer (CEO), Chief Financial Officer (CFO), Chief Operating Officer (COO) and Chief Technical Officer (CTO).The CTO may also serve as CIO, and vice versa.
Knowledge management
Knowledge Management (KM) comprises a range of practices used in an organisation to identify, create, represent, distribute and enable adoption of insights and experiences. Such insights and experiences comprise knowledge, either embodied in individuals or embedded in organisational processes or practice. KM has been an established discipline since 1995 with a body of courses in universities to include business administration, information systems, management, and library and information sciences . More recently, other schools, to include those focused on information and media, computer science, public health, and public policy, also have started to contribute. Many large companies and non-profit organisations have resources dedicated to internal KM efforts, often as a part of their 'Business Strategy', 'Information Technology', or 'Human Resource Management' departments . Several consulting companies also exist that provide strategy and advice regarding KM to these organisations.
KM efforts typically focus on organisational objectives such as improved performance, competitive advantage, innovation, developmental processes, the sharing of lessons learned, and continuous improvement of the organisation. KM efforts overlap with Organisational Learning, and may be distinguished from by a greater focus on the management of knowledge as a strategic asset and a focus on encouraging the exchange of knowledge. KM efforts can help individuals and groups to share valuable organisational insights, to reduce redundant work, to avoid 're-inventing the wheel' per se, to reduce training time for new employees, to retain intellectual capital as employees turnover in an organisation, and to adapt to changing environments and markets .
http://en.wikipedia.org/wiki/Knowledge_management
KM efforts typically focus on organisational objectives such as improved performance, competitive advantage, innovation, developmental processes, the sharing of lessons learned, and continuous improvement of the organisation. KM efforts overlap with Organisational Learning, and may be distinguished from by a greater focus on the management of knowledge as a strategic asset and a focus on encouraging the exchange of knowledge. KM efforts can help individuals and groups to share valuable organisational insights, to reduce redundant work, to avoid 're-inventing the wheel' per se, to reduce training time for new employees, to retain intellectual capital as employees turnover in an organisation, and to adapt to changing environments and markets .
http://en.wikipedia.org/wiki/Knowledge_management
วันจันทร์ที่ 3 พฤศจิกายน พ.ศ. 2551
The History of Computers
Who invented the computer?" is not a question with a simple answer. The real answer is that many inventors contributed to the history of computers and that a computer is a complex piece of machinery made up of many parts, each of which can be considered a separate invention.
This series covers many of the major milestones in computer history (but not all of them) with a concentration on the history of personal home computers
Computer History Year/Enter
Computer History Inventors/Inventions
Computer History Description of Event
1936
Konrad Zuse - Z1 Computer
First freely programmable computer.
1942
John Atanasoff & Clifford Berry ABC Computer
Who was first in the computing biz is not always as easy as ABC.
1944
Howard Aiken & Grace Hopper Harvard Mark I Computer
The Harvard Mark 1 computer.
1946
John Presper Eckert & John W. Mauchly ENIAC 1 Computer
20,000 vacuum tubes later...
1948
Frederic Williams & Tom Kilburn Manchester Baby Computer & The Williams Tube
Baby and the Williams Tube turn on the memories.
1947/48
John Bardeen, Walter Brattain & Wiliam Shockley The Transistor
No, a transistor is not a computer, but this invention greatly affected the history of computers.
1951
John Presper Eckert & John W. Mauchly UNIVAC Computer
First commercial computer & able to pick presidential winners.
1953
International Business Machines IBM 701 EDPM Computer
IBM enters into 'The History of Computers'.
1954
John Backus & IBM FORTRAN Computer Programming Language
The first successful high level programming language.
1955(In Use 1959)
Stanford Research Institute, Bank of America, and General ElectricERMA and MICR
The first bank industry computer - also MICR (magnetic ink character recognition) for reading checks.
1958
Jack Kilby & Robert Noyce The Integrated Circuit
Otherwise known as 'The Chip'
1962
Steve Russell & MIT Spacewar Computer Game
The first computer game invented.
1964
Douglas Engelbart Computer Mouse & Windows
Nicknamed the mouse because the tail came out the end.
1969
ARPAnet
The original Internet.
1970
Intel 1103 Computer Memory
The world's first available dynamic RAM chip.
1971
Faggin, Hoff & Mazor Intel 4004 Computer Microprocessor
The first microprocessor.
1971
Alan Shugart &IBM The "Floppy" Disk
Nicknamed the "Floppy" for its flexibility.
1973
Robert Metcalfe & Xerox The Ethernet Computer Networking
Networking.
1974/75
Scelbi & Mark-8 Altair & IBM 5100 Computers
The first consumer computers.
1976/77
Apple I, II & TRS-80 & Commodore Pet Computers
More first consumer computers.
1978
Dan Bricklin & Bob Frankston VisiCalc Spreadsheet Software
Any product that pays for itself in two weeks is a surefire winner.
1979
Seymour Rubenstein & Rob Barnaby WordStar Software
Word Processors.
1981
IBM The IBM PC - Home Computer
From an "Acorn" grows a personal computer revolution
1981
Microsoft MS-DOS Computer Operating System
From "Quick And Dirty" comes the operating system of the century.
1983
Apple Lisa Computer
The first home computer with a GUI, graphical user interface.
1984
Apple Macintosh Computer
The more affordable home computer with a GUI.
1985
Microsoft Windows
Microsoft begins the friendly war with Apple.
http://inventors.about.com/library/blcoindex.htm
This series covers many of the major milestones in computer history (but not all of them) with a concentration on the history of personal home computers
Computer History Year/Enter
Computer History Inventors/Inventions
Computer History Description of Event
1936
Konrad Zuse - Z1 Computer
First freely programmable computer.
1942
John Atanasoff & Clifford Berry ABC Computer
Who was first in the computing biz is not always as easy as ABC.
1944
Howard Aiken & Grace Hopper Harvard Mark I Computer
The Harvard Mark 1 computer.
1946
John Presper Eckert & John W. Mauchly ENIAC 1 Computer
20,000 vacuum tubes later...
1948
Frederic Williams & Tom Kilburn Manchester Baby Computer & The Williams Tube
Baby and the Williams Tube turn on the memories.
1947/48
John Bardeen, Walter Brattain & Wiliam Shockley The Transistor
No, a transistor is not a computer, but this invention greatly affected the history of computers.
1951
John Presper Eckert & John W. Mauchly UNIVAC Computer
First commercial computer & able to pick presidential winners.
1953
International Business Machines IBM 701 EDPM Computer
IBM enters into 'The History of Computers'.
1954
John Backus & IBM FORTRAN Computer Programming Language
The first successful high level programming language.
1955(In Use 1959)
Stanford Research Institute, Bank of America, and General ElectricERMA and MICR
The first bank industry computer - also MICR (magnetic ink character recognition) for reading checks.
1958
Jack Kilby & Robert Noyce The Integrated Circuit
Otherwise known as 'The Chip'
1962
Steve Russell & MIT Spacewar Computer Game
The first computer game invented.
1964
Douglas Engelbart Computer Mouse & Windows
Nicknamed the mouse because the tail came out the end.
1969
ARPAnet
The original Internet.
1970
Intel 1103 Computer Memory
The world's first available dynamic RAM chip.
1971
Faggin, Hoff & Mazor Intel 4004 Computer Microprocessor
The first microprocessor.
1971
Alan Shugart &IBM The "Floppy" Disk
Nicknamed the "Floppy" for its flexibility.
1973
Robert Metcalfe & Xerox The Ethernet Computer Networking
Networking.
1974/75
Scelbi & Mark-8 Altair & IBM 5100 Computers
The first consumer computers.
1976/77
Apple I, II & TRS-80 & Commodore Pet Computers
More first consumer computers.
1978
Dan Bricklin & Bob Frankston VisiCalc Spreadsheet Software
Any product that pays for itself in two weeks is a surefire winner.
1979
Seymour Rubenstein & Rob Barnaby WordStar Software
Word Processors.
1981
IBM The IBM PC - Home Computer
From an "Acorn" grows a personal computer revolution
1981
Microsoft MS-DOS Computer Operating System
From "Quick And Dirty" comes the operating system of the century.
1983
Apple Lisa Computer
The first home computer with a GUI, graphical user interface.
1984
Apple Macintosh Computer
The more affordable home computer with a GUI.
1985
Microsoft Windows
Microsoft begins the friendly war with Apple.
http://inventors.about.com/library/blcoindex.htm
วันอังคารที่ 30 กันยายน พ.ศ. 2551
Submarine
A submarine is a watercraft that can operate independently below water, as distinct from a submersible that has only limited underwater capability. The term submarine most commonly refers to large manned autonomous vessels, however historically or more casually, submarine can also refer to medium sized or smaller vessels, (midget submarines, wet subs), Remotely Operated Vehicles or robots. The word submarine was originally an adjective meaning "under the sea", and so consequently other uses such as "submarine engineering" or "submarine cable" may not actually refer to submarines at all. Submarine was shortened from the term "submarine boat".
Submarines are referred to as "boats" for historical reasons because vessels deployed from a ship are referred to as boats. The first submarines were launched in such a manner. The English term U-Boat for a German submarine comes from the German word for submarine, U-Boot, itself an abbreviation for Unterseeboot ("undersea boat").
Although experimental submarines had been built before, submarine design took off during the 19th century. Submarines were first widely used in World War I, and feature in many large navies. Military usage ranges from attacking enemy ships or submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance, conventional land attack (for example using a cruise missile), and covert insertion of special forces. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarines can also be specialised to a function such as search and rescue, or undersea cable repair. Submarines are also used in tourism and for academic research.
Submarines have one of the largest ranges in capabilities of any vessel, ranging from small autonomous or one- or two-man vessels operating for a few hours, to vessels which can remain submerged for 6 months such as the Russian Typhoon class. Submarines can work at greater depths than are survivable or practical for human divers. Modern deep diving submarines are derived from the bathyscaphe, which in turn was an evolution of the diving bell.
Most large submarines comprise a cylindrical body with conical ends and a vertical structure, usually located amidships, which houses communications and sensing devices as well as periscopes. In modern submarines this structure is the "sail" in American usage ("fin" in European usage). A "conning tower" was a feature of earlier designs: a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller (or pump jet) at the rear and various hydrodynamic control fins as well as ballast tanks. Smaller, deep diving and specialty submarines may deviate significantly from this traditional layout.
Submarines are referred to as "boats" for historical reasons because vessels deployed from a ship are referred to as boats. The first submarines were launched in such a manner. The English term U-Boat for a German submarine comes from the German word for submarine, U-Boot, itself an abbreviation for Unterseeboot ("undersea boat").
Although experimental submarines had been built before, submarine design took off during the 19th century. Submarines were first widely used in World War I, and feature in many large navies. Military usage ranges from attacking enemy ships or submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance, conventional land attack (for example using a cruise missile), and covert insertion of special forces. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarines can also be specialised to a function such as search and rescue, or undersea cable repair. Submarines are also used in tourism and for academic research.
Submarines have one of the largest ranges in capabilities of any vessel, ranging from small autonomous or one- or two-man vessels operating for a few hours, to vessels which can remain submerged for 6 months such as the Russian Typhoon class. Submarines can work at greater depths than are survivable or practical for human divers. Modern deep diving submarines are derived from the bathyscaphe, which in turn was an evolution of the diving bell.
Most large submarines comprise a cylindrical body with conical ends and a vertical structure, usually located amidships, which houses communications and sensing devices as well as periscopes. In modern submarines this structure is the "sail" in American usage ("fin" in European usage). A "conning tower" was a feature of earlier designs: a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller (or pump jet) at the rear and various hydrodynamic control fins as well as ballast tanks. Smaller, deep diving and specialty submarines may deviate significantly from this traditional layout.
Ghost
A ghost is said to be the apparition of a deceased person, frequently similar in appearance to that person, and usually encountered in places she or he frequented, the place of his or her death, or in association with the person's former belongings. The word "ghost" may also refer to the spirit or soul of a deceased person, or to any spirit or demon.[1][2][3] A place in which ghosts are supposed to appear is described as haunted. A related phenomenon is the poltergeist, literally a 'noisy spirit' that manifests itself by moving and influencing objects, though a widespread view today is that these occurences are either fraudulent or manifestations of the psychic energy of, particularly, adolescent girls.[4] Phantom armies, animals, trains and ships have also been reported.[5][6]
The reality of ghosts is a vexed subject which divides believers and skeptics.[7] The study of ghosts is both the subject of folklore and also, since the nineteenth century, of the investigations of parapsychologists, who have attempted to refine the vocabulary used in describing ghostly phenomena. Summoning or exorcising the shades of the departed is an item of belief and religious practice for spiritualists and practitioners of ritual magic. Though some claims of ghostly phenomena are proven frauds others remain unexplained or are subject to conflicting explanations. So far no one explanation has gained universal acceptance.[8] According to a poll conducted in 2005 by the Gallup Organization about 32% of Americans believe in the existence of ghosts
The reality of ghosts is a vexed subject which divides believers and skeptics.[7] The study of ghosts is both the subject of folklore and also, since the nineteenth century, of the investigations of parapsychologists, who have attempted to refine the vocabulary used in describing ghostly phenomena. Summoning or exorcising the shades of the departed is an item of belief and religious practice for spiritualists and practitioners of ritual magic. Though some claims of ghostly phenomena are proven frauds others remain unexplained or are subject to conflicting explanations. So far no one explanation has gained universal acceptance.[8] According to a poll conducted in 2005 by the Gallup Organization about 32% of Americans believe in the existence of ghosts
วันจันทร์ที่ 15 กันยายน พ.ศ. 2551
Aeroflot Flight 821
Aeroflot Flight 821, operated by Aeroflot-Nord in a service agreement with Aeroflot,[1] crashed on approach to Perm Airport on 14 September 2008.[2][3][4] All 82 passengers and 6 crew members were killed. The weather at the time of accident was rainy and foggy. The aircraft, a Boeing 737-500 registration VP-BKO, departed from Moscow's Sheremetyevo International Airport. A part of the Trans-Siberian Railway was also reportedly damaged in the crash.[5]
วันจันทร์ที่ 8 กันยายน พ.ศ. 2551
Global warming
Global warming is the increase in the average measured temperature of the Earth's near-surface air and oceans since the mid-20th century, and its projected continuation.
The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 100 years ending in 2005.[1] The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations"[1] via an enhanced greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward.[2][3]
These basic conclusions have been endorsed by at least 30 scientific societies and academies of science,[4] including all of the national academies of science of the major industrialized countries.[5][6][7] While individual scientists have voiced disagreement with some findings of the IPCC,[8] the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.[9][10]
Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century.[1] This range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.[1]
Increasing global temperature is expected to cause sea levels to rise, an increase in the intensity of extreme weather events, and significant changes to the amount and pattern of precipitation, likely leading to an expanse of tropical areas and increased pace of desertification. Other expected effects of global warming include changes in agricultural yields, modifications of trade routes, glacier retreat, mass species extinctions and increases in the ranges of disease vectors.
Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.
The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 100 years ending in 2005.[1] The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations"[1] via an enhanced greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward.[2][3]
These basic conclusions have been endorsed by at least 30 scientific societies and academies of science,[4] including all of the national academies of science of the major industrialized countries.[5][6][7] While individual scientists have voiced disagreement with some findings of the IPCC,[8] the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.[9][10]
Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century.[1] This range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.[1]
Increasing global temperature is expected to cause sea levels to rise, an increase in the intensity of extreme weather events, and significant changes to the amount and pattern of precipitation, likely leading to an expanse of tropical areas and increased pace of desertification. Other expected effects of global warming include changes in agricultural yields, modifications of trade routes, glacier retreat, mass species extinctions and increases in the ranges of disease vectors.
Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.
วันจันทร์ที่ 25 สิงหาคม พ.ศ. 2551
Drug
Drug
A drug, broadly speaking, is any chemical substance that, when absorbed into the body of a living organism, alters normal bodily function[5]. There is no single, precise definition, as there are different meanings in medicine, government regulations, and colloquial usage.[6]
In pharmacology, Dictionary.com defines a drug as "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being."[6] Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders.[7]
Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens.[7] They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior.[7][8] Some recreational drugs can cause addiction and habituation.[8]
Drugs are usually distinguished from endogenous biochemicals by being introduced from outside the organism.[citation needed] For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug.[citation needed]
Many natural substances such as beers, wines, and some mushrooms, blur the line between food and drugs, as when ingested they affect the functioning of both mind and body.
http://en.wikipedia.org/wiki/Drug
A drug, broadly speaking, is any chemical substance that, when absorbed into the body of a living organism, alters normal bodily function[5]. There is no single, precise definition, as there are different meanings in medicine, government regulations, and colloquial usage.[6]
In pharmacology, Dictionary.com defines a drug as "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being."[6] Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders.[7]
Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens.[7] They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior.[7][8] Some recreational drugs can cause addiction and habituation.[8]
Drugs are usually distinguished from endogenous biochemicals by being introduced from outside the organism.[citation needed] For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug.[citation needed]
Many natural substances such as beers, wines, and some mushrooms, blur the line between food and drugs, as when ingested they affect the functioning of both mind and body.
http://en.wikipedia.org/wiki/Drug
Medication
Main article: Medication
A medication or medicine is a drug taken to cure and/or ameliorate any symptoms of an illness or medical condition, or may be used as preventive medicine that has future benefits but does not treat any existing or pre-existing diseases or symptoms.
Dispensing of medication is often regulated by governments into three categories — over-the-counter (OTC) medications, which are available in pharmacies and supermarkets without special restrictions, behind-the-counter (BTC), which are dispensed by a pharmacist without needing a doctor's prescription, and Prescription only medicines (POM), which must be prescribed by a licensed medical professional, usually a physician.[citation needed]
In the UK, BTC medicines are called pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist, these medications are designated by the letter P on the label [1], the precise distinction between OTC and prescription drugs depends on the legal jurisdiction.[citation needed]
Medications are typically produced by pharmaceutical companies and are often patented to give the developer exclusive rights to produce them, but they can also be derived from naturally occurring substance in plants called herbal medicine.[citation needed] Those that are not patented (or with expired patents) are called generic drugs since they can be produced by other companies without restrictions or licenses from the patent holder.
Drugs, both medicinal and recreational, can be administered in a number of ways:
Orally, as a liquid or solid, that is absorbed through the stomach.
Inhaled, (breathed into the lungs), as a vapor.
Injected as a liquid either: intramuscular, intravenous, intraperitoneal, intraosseous.
Rectally as a suppository, that is absorbed by the colon.
Vaginally as a suppository, primarily to treat vaginal infections.
Bolus, a substance into the stomach to dissolve slowly.
Insufflation, or snorted into the nose.
Many drugs can be administered in a variety of ways.
Main article: Medication
A medication or medicine is a drug taken to cure and/or ameliorate any symptoms of an illness or medical condition, or may be used as preventive medicine that has future benefits but does not treat any existing or pre-existing diseases or symptoms.
Dispensing of medication is often regulated by governments into three categories — over-the-counter (OTC) medications, which are available in pharmacies and supermarkets without special restrictions, behind-the-counter (BTC), which are dispensed by a pharmacist without needing a doctor's prescription, and Prescription only medicines (POM), which must be prescribed by a licensed medical professional, usually a physician.[citation needed]
In the UK, BTC medicines are called pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist, these medications are designated by the letter P on the label [1], the precise distinction between OTC and prescription drugs depends on the legal jurisdiction.[citation needed]
Medications are typically produced by pharmaceutical companies and are often patented to give the developer exclusive rights to produce them, but they can also be derived from naturally occurring substance in plants called herbal medicine.[citation needed] Those that are not patented (or with expired patents) are called generic drugs since they can be produced by other companies without restrictions or licenses from the patent holder.
Drugs, both medicinal and recreational, can be administered in a number of ways:
Orally, as a liquid or solid, that is absorbed through the stomach.
Inhaled, (breathed into the lungs), as a vapor.
Injected as a liquid either: intramuscular, intravenous, intraperitoneal, intraosseous.
Rectally as a suppository, that is absorbed by the colon.
Vaginally as a suppository, primarily to treat vaginal infections.
Bolus, a substance into the stomach to dissolve slowly.
Insufflation, or snorted into the nose.
Many drugs can be administered in a variety of ways.
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