Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not. Variation exists within all populations of organisms; this occurs because random mutations arise in the genome of an individual organism, offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits; the environment of a genome includes the molecular biology in the cell, other cells, other individuals, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend to survive and reproduce more than individuals with other, less successful variants, the population evolves.
Other factors affecting reproductive success include fecundity selection. Natural selection acts on the phenotype, the characteristics of the organism which interact with the environment, but the genetic basis of any phenotype that gives that phenotype a reproductive advantage may become more common in a population. Over time, this process can result in populations that specialise for particular ecological niches and may result in speciation. In other words, natural selection is a key process in the evolution of a population. Natural selection is a cornerstone of modern biology; the concept, published by Darwin and Alfred Russel Wallace in a joint presentation of papers in 1858, was elaborated in Darwin's influential 1859 book On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. He described natural selection as analogous to artificial selection, a process by which animals and plants with traits considered desirable by human breeders are systematically favoured for reproduction.
The concept of natural selection developed in the absence of a valid theory of heredity. The union of traditional Darwinian evolution with subsequent discoveries in classical genetics formed the modern synthesis of the mid-20th century; the addition of molecular genetics has led to evolutionary developmental biology, which explains evolution at the molecular level. While genotypes can change by random genetic drift, natural selection remains the primary explanation for adaptive evolution. Several philosophers of the classical era, including Empedocles and his intellectual successor, the Roman poet Lucretius, expressed the idea that nature produces a huge variety of creatures and that only those creatures that manage to provide for themselves and reproduce persist. Empedocles' idea that organisms arose by the incidental workings of causes such as heat and cold was criticised by Aristotle in Book II of Physics, he posited natural teleology in its place, believed that form was achieved for a purpose, citing the regularity of heredity in species as proof.
He accepted in his biology that new types of animals, can occur in rare instances. As quoted in Darwin's 1872 edition of The Origin of Species, Aristotle considered whether different forms might have appeared accidentally, but only the useful forms survived: So what hinders the different parts from having this accidental relation in nature? as the teeth, for example, grow by necessity, the front ones sharp, adapted for dividing, the grinders flat, serviceable for masticating the food. And in like manner as to the other parts in which there appears to exist an adaptation to an end. Wheresoever, all things together happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal spontaneity, whatsoever things were not thus constituted and still perish, but Aristotle rejected this possibility in the next paragraph, making clear that he is talking about the development of animals as embryos with the phrase "either invariably or come about", not the origin of species:...
Yet it is impossible. For teeth and all other natural things either invariably or come about in a given way. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but frequent rain in summer we do. If it is agreed that things are either the result of coincidence or for an end, these cannot be the result of coincidence or spontaneity, it follows that they must be for an end; therefore action for an end is present in things which are by nature. The struggle for existence was described by the Islamic writer Al-Jahiz in the 9th century; the classical arguments were reintroduced in the 18th century by Pierre Louis Maupertuis and others, including Darwin's grandfather, Erasmus Darwin. Until the early 19th century, the prevailing view in Western societies was that differences between individuals of a species were uninteresting departures from their Platonic i
Système universitaire de documentation
The système universitaire de documentation or SUDOC is a system used by the libraries of French universities and higher education establishments to identify and manage the documents in their possession. The catalog, which contains more than 10 million references, allows students and researcher to search for bibliographical and location information in over 3,400 documentation centers, it is maintained by the Bibliographic Agency for Higher Education. Official website
National Library of Australia
The National Library of Australia is the largest reference library in Australia, responsible under the terms of the National Library Act for "maintaining and developing a national collection of library material, including a comprehensive collection of library material relating to Australia and the Australian people." In 2012–13, the National Library collection comprised 6,496,772 items, an additional 15,506 metres of manuscript material. It is located in Parkes, Canberra, ACT; the National Library of Australia, while formally established by the passage of the National Library Act 1960, had been functioning as a national library rather than a Parliamentary Library since its inception. In 1901, a Commonwealth Parliamentary Library was established to serve the newly formed Federal Parliament of Australia. From its inception the Commonwealth Parliamentary Library was driven to development of a national collection. In 1907 the Joint Parliamentary Library Committee under the Chairmanship of the Speaker, Sir Frederick William Holder defined the objective of the Commonwealth Parliamentary Library in the following words: The Library Committee is keeping before it the ideal of building up, for the time when Parliament shall be established in the Federal Capital, a great Public Library on the lines of the world-famed Library of Congress at Washington.
The present library building was opened on 15 August 1968 by Prime Minister John Gorton. The building was designed by the architectural firm of Bunning and Madden in the Late Twentieth Century Stripped Classical style; the foyer is decorated in marble, with stained-glass windows by Leonard French and three tapestries by Mathieu Matégot. The building was listed on the Australian Commonwealth Heritage List on 22 June 2004. In 2012–13 the Library collection comprised 6,496,772 items, with an estimated additional 2,325,900 items held in the manuscripts collection; the Library's collections of Australiana have developed into the nation's single most important resource of materials recording the Australian cultural heritage. Australian writers and illustrators are sought and well represented—whether published in Australia or overseas; the Library's collection includes all formats of material, from books, journals and manuscripts to pictures, maps, oral history recordings, manuscript papers and ephemera.
92.1% of the Library's collection has been catalogued and is discoverable through the online catalogue. The Library has digitized over 174,000 items from its collection and, where possible, delivers these directly across the Internet; the Library is a world leader in digital preservation techniques, maintains an Internet-accessible archive of selected Australian websites called the Pandora Archive. The Library collects material produced by Australians, for Australians or about the Australian experience in all formats—not just printed works—books, newspapers, posters and printed ephemera—but online publications and unpublished material such as manuscripts and oral histories. A core Australiana collection is that of John A. Ferguson; the Library has particular collection strengths in the performing arts, including dance. The Library's considerable collections of general overseas and rare book materials, as well as world-class Asian and Pacific collections which augment the Australiana collections.
The print collections are further supported by extensive microform holdings. The Library maintains the National Reserve Braille Collection; the Library houses the largest and most developing research resource on Asia in Australia, the largest Asian language collections in the Southern hemisphere, with over half a million volumes in the collection, as well as extensive online and electronic resources. The Library collects resources about all Asian countries in Western languages extensively, resources in the following Asian languages: Burmese, Persian, Japanese, Korean, Manchu, Thai and Vietnamese; the Library has acquired a number of important Western and Asian language scholarly collections from researchers and bibliophiles. These collections include: Australian Buddhist Library Collection Braga Collection Claasz Collection Coedes Collection London Missionary Society Collection Luce Collection McLaren-Human Collection Otley Beyer Collection Sakakibara Collection Sang Ye Collection Simon Collection Harold S. Williams Collection The Asian Collections are searchable via the National Library's catalogue.
The National Library holds an extensive collection of manuscripts. The manuscript collection contains about 26 million separate items, covering in excess of 10,492 meters of shelf space; the collection relates predominantly to Australia, but there are important holdings relating to Papua New Guinea, New Zealand and the Pacific. The collection holds a number of European and Asian manuscript collections or single items have been received as part of formed book collections; the Australian manuscript collections date from the period of maritime exploration and settlement in the 18th century until the present, with the greatest area of strength dating from the 1890s onwards. The collection includes a large number of outstanding single items, such as the 14th century Chertsey Cartulary, the journal of James Cook on the HM Bark Endeavour, inscribed on t
OCLC Online Computer Library Center, Incorporated d/b/a OCLC is an American nonprofit cooperative organization "dedicated to the public purposes of furthering access to the world's information and reducing information costs". It was founded in 1967 as the Ohio College Library Center. OCLC and its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded by the fees that libraries have to pay for its services. OCLC maintains the Dewey Decimal Classification system. OCLC began in 1967, as the Ohio College Library Center, through a collaboration of university presidents, vice presidents, library directors who wanted to create a cooperative computerized network for libraries in the state of Ohio; the group first met on July 5, 1967 on the campus of the Ohio State University to sign the articles of incorporation for the nonprofit organization, hired Frederick G. Kilgour, a former Yale University medical school librarian, to design the shared cataloging system.
Kilgour wished to merge the latest information storage and retrieval system of the time, the computer, with the oldest, the library. The plan was to merge the catalogs of Ohio libraries electronically through a computer network and database to streamline operations, control costs, increase efficiency in library management, bringing libraries together to cooperatively keep track of the world's information in order to best serve researchers and scholars; the first library to do online cataloging through OCLC was the Alden Library at Ohio University on August 26, 1971. This was the first online cataloging by any library worldwide. Membership in OCLC is based on use of services and contribution of data. Between 1967 and 1977, OCLC membership was limited to institutions in Ohio, but in 1978, a new governance structure was established that allowed institutions from other states to join. In 2002, the governance structure was again modified to accommodate participation from outside the United States.
As OCLC expanded services in the United States outside Ohio, it relied on establishing strategic partnerships with "networks", organizations that provided training and marketing services. By 2008, there were 15 independent United States regional service providers. OCLC networks played a key role in OCLC governance, with networks electing delegates to serve on the OCLC Members Council. During 2008, OCLC commissioned two studies to look at distribution channels. In early 2009, OCLC negotiated new contracts with the former networks and opened a centralized support center. OCLC provides bibliographic and full-text information to anyone. OCLC and its member libraries cooperatively produce and maintain WorldCat—the OCLC Online Union Catalog, the largest online public access catalog in the world. WorldCat has holding records from private libraries worldwide; the Open WorldCat program, launched in late 2003, exposed a subset of WorldCat records to Web users via popular Internet search and bookselling sites.
In October 2005, the OCLC technical staff began a wiki project, WikiD, allowing readers to add commentary and structured-field information associated with any WorldCat record. WikiD was phased out; the Online Computer Library Center acquired the trademark and copyrights associated with the Dewey Decimal Classification System when it bought Forest Press in 1988. A browser for books with their Dewey Decimal Classifications was available until July 2013; until August 2009, when it was sold to Backstage Library Works, OCLC owned a preservation microfilm and digitization operation called the OCLC Preservation Service Center, with its principal office in Bethlehem, Pennsylvania. The reference management service QuestionPoint provides libraries with tools to communicate with users; this around-the-clock reference service is provided by a cooperative of participating global libraries. Starting in 1971, OCLC produced catalog cards for members alongside its shared online catalog. OCLC commercially sells software, such as CONTENTdm for managing digital collections.
It offers the bibliographic discovery system WorldCat Discovery, which allows for library patrons to use a single search interface to access an institution's catalog, database subscriptions and more. OCLC has been conducting research for the library community for more than 30 years. In accordance with its mission, OCLC makes its research outcomes known through various publications; these publications, including journal articles, reports and presentations, are available through the organization's website. OCLC Publications – Research articles from various journals including Code4Lib Journal, OCLC Research, Reference & User Services Quarterly, College & Research Libraries News, Art Libraries Journal, National Education Association Newsletter; the most recent publications are displayed first, all archived resources, starting in 1970, are available. Membership Reports – A number of significant reports on topics ranging from virtual reference in libraries to perceptions about library funding. Newsletters – Current and archived newsletters for the library and archive community.
Presentations – Presentations from both guest speakers and OCLC research from conferences and other events. The presentations are organized into five categories: Conference presentations, Dewey presentations, Distinguished Seminar Series, Guest presentations, Research staff
Integrated Authority File
The Integrated Authority File or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used for documentation in libraries and also by archives and museums; the GND is managed by the German National Library in cooperation with various regional library networks in German-speaking Europe and other partners. The GND falls under the Creative Commons Zero licence; the GND specification provides a hierarchy of high-level entities and sub-classes, useful in library classification, an approach to unambiguous identification of single elements. It comprises an ontology intended for knowledge representation in the semantic web, available in the RDF format; the Integrated Authority File became operational in April 2012 and integrates the content of the following authority files, which have since been discontinued: Name Authority File Corporate Bodies Authority File Subject Headings Authority File Uniform Title File of the Deutsches Musikarchiv At the time of its introduction on 5 April 2012, the GND held 9,493,860 files, including 2,650,000 personalised names.
There are seven main types of GND entities: LIBRIS Virtual International Authority File Information pages about the GND from the German National Library Search via OGND Bereitstellung des ersten GND-Grundbestandes DNB, 19 April 2012 From Authority Control to Linked Authority Data Presentation given by Reinhold Heuvelmann to the ALA MARC Formats Interest Group, June 2012
Du Noüy ring method
The du Noüy ring method is a technique for measuring the surface tension of a liquid. The method involves lifting a ring made of platinum, from the surface of a liquid; the force, F, required to raise the ring from the liquid's surface is measured and related to the liquid's surface tension, γ: F = w + 2 π ⋅ ⋅ γ where r i is the radius of the inner ring of the liquid film pulled and r a is the radius of the outer ring of the liquid film. W is the weight of the ring minus the buoyant force due to the part of the ring below the liquid surface; when the ring's thickness is much smaller than its diameter, this equation can be simplified to: F = w + 4 π R γ where R is the average of the inner and outer radius of the ring. This technique was proposed by the French physicist Pierre Lecomte du Noüy in a paper published in 1925; the measurement is performed with a force tensiometer, which uses an electrobalance to measure the excess force caused by the liquid being pulled up and automatically calculates and displays the surface tension corresponding to the force.
Earlier, torsion wire balances were used. The maximum force is used for the calculations, empirically determined correction factors are required to remove the effect caused by the finite diameter of the ring: F = w + 4 π R γ f with f being the correction factor; the most common correction factors include those by Zuidema and Waters and Mason, Harkins and Jordan. Sessile drop technique Wilhelmy plate Video of a modern automated force tensiometer Video showing a classical torsion wire du Noüy tensiometer Picture of a classical torsion wire du Noüy tensiometer