Sexual intercourse is principally the insertion and thrusting of the penis when erect, into the vagina for sexual pleasure, reproduction, or both. This is known as vaginal intercourse or vaginal sex. Other forms of penetrative sexual intercourse include anal sex, oral sex and penetration by use of a dildo; these activities involve physical intimacy between two or more individuals and are used among humans for physical or emotional pleasure and can contribute to human bonding. There are different views on what constitutes sexual intercourse or other sexual activity, which can impact on views on sexual health. Although sexual intercourse the variant coitus denotes penile–vaginal penetration and the possibility of creating offspring, it commonly denotes penetrative oral sex and penile–anal sex the latter, it encompasses sexual penetration, while non-penetrative sex has been labeled "outercourse", but non-penetrative sex may be considered sexual intercourse. Sex a shorthand for sexual intercourse, can mean any form of sexual activity.
Because people can be at risk of contracting sexually transmitted infections during these activities, safe sex practices are advised, although transmission risk is reduced during non-penetrative sex. Various jurisdictions have placed restrictive laws against certain sexual acts, such as incest, sexual activity with minors, rape, sodomy and extramarital sex. Religious beliefs play a role in personal decisions about sexual intercourse or other sexual activity, such as decisions about virginity, or legal and public policy matters. Religious views on sexuality vary between different religions and sects of the same religion, though there are common themes, such as prohibition of adultery. Reproductive sexual intercourse between non-human animals is more called copulation, sperm may be introduced into the female's reproductive tract in non-vaginal ways among the animals, such as by cloacal copulation. For most non-human mammals and copulation occur at the point of estrus, which increases the chances of successful impregnation.
However, bonobos and chimpanzees are known to engage in sexual intercourse regardless of whether or not the female is in estrus, to engage in sex acts with same-sex partners. Like humans engaging in sexual activity for pleasure, this behavior in these animals is presumed to be for pleasure, a contributing factor to strengthening their social bonds. Sexual intercourse may be called coitus, coition, or intercourse. Coitus is derived from the Latin word coitio or coire, meaning "a coming together or joining together" or "to go together", is known under different ancient Latin names for a variety of sexual activities, but denotes penile–vaginal penetration; this is called vaginal intercourse or vaginal sex. Vaginal sex, less vaginal intercourse, may denote any vaginal sexual activity if penetrative, including sexual activity between lesbian couples. Copulation, by contrast, more denotes the mating process for non-human animals. Although sexual intercourse and sex most denote penile–vaginal intercourse and the phrase "have sex" can be broad in their meaning and may cover any penetrative or non-penetrative sexual activity between two or more people.
The World Health Organization states that non-English languages and cultures use different words for sexual activity, "with different meanings". Various vulgarisms and euphemisms are used for sexual intercourse or other sexual activity, such as fuck and the phrase "sleep together"; the laws of some countries use the euphemism "carnal knowledge." Penetration of the vagina by the erect penis is additionally known as intromission, or by the Latin name immissio penis. The age of first sexual intercourse is called sexarche. Vaginal and oral sex are recognized as sexual intercourse more than other sexual behaviors. While non-penetrative and non-penile–vaginal sexual activities may be regarded as sexual intercourse, they might alternatively be considered a means of maintaining virginity" or labeled "outercourse", regardless of any penetrative aspects, more the case for oral sex than for anal sex. Virginity loss is based on penile–vaginal intercourse because heterosexual couples may engage in anal or oral sex not only for sexual pleasure, but additionally as a way of maintaining that they are virgins if they have not engaged in the reproductive act of coitus.
Some gay men consider frotting or oral sex as a way of maintaining their virginities, with penile-anal penetration used as sexual intercourse and for virginity loss, while other gay men may consider frotting or oral sex as their main forms of sexual activity. Lesbians may categorize oral sex or fingering as sexual intercourse and subsequently an act of virginity loss, or tribadism as a primary form of sexual activity. Researchers use sexual intercourse to denote penile–vaginal intercourse while using specific wo
Therapsida is a group of synapsids that includes mammals and their ancestors. Many of the traits today seen as unique to mammals had their origin within early therapsids, including having their four limbs extend vertically beneath the body, as opposed to the sprawling posture of reptiles; the earliest fossil attributed to Therapsida is Tetraceratops insignis from the Lower Permian. Therapsids evolved from "pelycosaurs" within the Sphenacodontia, more than 275 million years ago, they replaced the "pelycosaurs" as the dominant large land animals in the Middle Permian and were replaced, in turn, by the archosauromorphs in the Triassic, although one group of therapsids, the kannemeyeriiforms, remained diverse in the Late Triassic. The therapsids included the cynodonts, the group that gave rise to mammals in the Late Triassic around 225 million years ago. Of the non-mammalian therapsids, only cynodonts survived the Triassic–Jurassic extinction event; the last of the non-mammalian therapsids, the tritylodontid cynodonts, became extinct in the Early Cretaceous 100 million years ago.
Compared to their pelycosaurian ancestors, early therapsids had similar skulls but different post-cranial morphology. Therapsid legs were positioned more vertically beneath their bodies than were the sprawling legs of reptiles and pelycosaurs. Compared to these groups, the feet were more symmetrical, with the first and last toes short and the middle toes long, an indication that the foot's axis was placed parallel to that of the animal, not sprawling out sideways; this orientation would have given a more mammal-like gait than the lizard-like gait of the pelycosaurs. Therapsids' temporal fenestrae were larger than those of the pelycosaurs; the jaws of some therapsids were more complex and powerful, the teeth were differentiated into frontal incisors for nipping, great lateral canines for puncturing and tearing, molars for shearing and chopping food. Several characteristics in therapsids have been noted as being consistent with the development of endothermy: the presence of turbinates, erect limbs vascularized bones and tail proportions conducive to the preservation of body heat, the absence of growth rings in bones.
Therefore, like modern mammals, non-mammalian therapsids were most warm-blooded. Recent studies on Permian coprolites showcase. Hair is by any means present in the docodont Castorocauda and several contemporary haramiyidans, whiskers are inferred from therocephalians and cynodonts. Therapsids evolved from a group of pelycosaurs called sphenacodonts. Therapsids became the dominant land animals in the Middle Permian. Therapsida consists of four major clades: the dinocephalians, the herbivorous anomodonts, the carnivorous biarmosuchians, the carnivorous theriodonts. After a brief burst of evolutionary diversity, the dinocephalians died out in the Middle Permian but the anomodont dicynodonts as well as the theriodont gorgonopsians and therocephalians flourished, being joined at the end of the Permian by the first of the cynodonts. Like all land animals, the therapsids were affected by the Permian–Triassic extinction event; the dicynodonts, now represented by a single family of large stocky herbivores, the Kannemeyeridae, the medium-sized cynodonts, flourished worldwide throughout the Early and Middle Triassic.
They disappear from the fossil record across much of Pangea at the end of the Carnian, although they continued for some time longer in the wet equatorial band and the south. Some exceptions were the still further derived eucynodonts. At least three groups of them survived, they all appeared in the Late Triassic period. The mammal-like family, survived into the Early Cretaceous. Another mammal-like family, are unknown than the Early Jurassic. Mammaliaformes was the third group, including similar animals. Many taxonomists refer to these animals as "mammals", though some limit the term to the mammalian crown group; the non-eucynodont cynodonts survived the Permian-Triassic extinction. By the Middle Triassic, only the eucynodonts remained; the therocephalians, relatives of the cynodonts, managed to survive the Permian-Triassic extinction and continued to diversify through the Early Triassic period. Approaching the end of the period, the therocephalians were in decline to eventual extinction outcompeted by the diversifying Saurian lineage of diapsids, equipped with sophisticated respiratory systems better suited to the hot and oxygen-poor world of the End-Triassic.
Dicynodonts were long thought to have become extinct near the end of the Triassic, but there is evidence that they survived into the Cretaceous. Their fossils have been found in Gondwana; this is an example of Lazarus taxon. Other animals that were common in the Triassic took refuge here, such as the temnospondyls. Mammals are the only living therapsids; the mammalian crown group, which evolved in the Early Jurassic period, radiated from a group of mammaliaforms that included the docodonts. The mammaliaforms themselves evolved from a lineage of the eucynodont suborder. Class Synapsida ORDER THERAPSIDA *? Family † Tetraceratopsidae Suborder † Biarmosuchia * Family † Biarmosuchidae Family † Eotitanosuchidae Eutherapsida Suborder † Dinocephalia Family † Estemmenosu
The primary gut that forms during gastrulation in the developing zygote is known as the archenteron or the digestive tube. It develops into the mesoderm of an animal; as primary mesenchyme cells detach from the vegetal pole in the gastrula and enter the fluid filled cavity in the center, the remaining cells at the vegetal pole flatten to form a vegetal plate. This buckles inwards towards the blastocoel in a process called invagination; the cells continue to be rearranged until the shallow dip formed by invagination transforms into a deeper, narrower pouch formed by the gastrula's endoderm. This narrowing and lengthening of the archenteron is driven by convergent extension; the open end of the archenteron is called the blastopore. The filopodia—thin fibers formed by the mesenchyme cells—found in a late gastrula contract to drag the tip of the archenteron across the blastocoel; the endoderm of the archenteron will fuse with the ectoderm of the blastocoel wall. At this point gastrulation is complete, the gastrula has a functional digestive tube.
The indentation, formed is called the lip of the blastopore or the dorsal lip in amphibians and fish, the primitive streak in birds and mammals. Each is controlled by the dorsal blastopore, primitive node, respectively. During gastrulation, the archenteron develops into the digestive tube, with the blastopore developing into either the mouth or the anus. Diagram
JSTOR is a digital library founded in 1995. Containing digitized back issues of academic journals, it now includes books and other primary sources, current issues of journals, it provides full-text searches of 2,000 journals. As of 2013, more than 8,000 institutions in more than 160 countries had access to JSTOR. JSTOR's revenue was $86 million in 2015. William G. Bowen, president of Princeton University from 1972 to 1988, founded JSTOR in 1995. JSTOR was conceived as a solution to one of the problems faced by libraries research and university libraries, due to the increasing number of academic journals in existence. Most libraries found it prohibitively expensive in terms of cost and space to maintain a comprehensive collection of journals. By digitizing many journal titles, JSTOR allowed libraries to outsource the storage of journals with the confidence that they would remain available long-term. Online access and full-text search ability improved access dramatically. Bowen considered using CD-ROMs for distribution.
However, Ira Fuchs, Princeton University's vice-president for Computing and Information Technology, convinced Bowen that CD-ROM was becoming an outdated technology and that network distribution could eliminate redundancy and increase accessibility. JSTOR was initiated in 1995 at seven different library sites, encompassed ten economics and history journals. JSTOR access improved based on feedback from its initial sites, it became a searchable index accessible from any ordinary web browser. Special software was put in place to make graphs clear and readable. With the success of this limited project and Kevin Guthrie, then-president of JSTOR, wanted to expand the number of participating journals, they met with representatives of the Royal Society of London and an agreement was made to digitize the Philosophical Transactions of the Royal Society dating from its beginning in 1665. The work of adding these volumes to JSTOR was completed by December 2000; the Andrew W. Mellon Foundation funded JSTOR initially.
Until January 2009 JSTOR operated as an independent, self-sustaining nonprofit organization with offices in New York City and in Ann Arbor, Michigan. JSTOR merged with the nonprofit Ithaka Harbors, Inc.—a nonprofit organization founded in 2003 and "dedicated to helping the academic community take full advantage of advancing information and networking technologies". JSTOR content is provided by more than 900 publishers; the database contains more than 1,900 journal titles, in more than 50 disciplines. Each object is uniquely identified by an integer value, starting at 1. In addition to the main site, the JSTOR labs group operates an open service that allows access to the contents of the archives for the purposes of corpus analysis at its Data for Research service; this site offers a search facility with graphical indication of the article coverage and loose integration into the main JSTOR site. Users may create focused sets of articles and request a dataset containing word and n-gram frequencies and basic metadata.
They may download it in either XML or CSV formats. The service does not offer full-text, although academics may request that from JSTOR, subject to a non-disclosure agreement. JSTOR Plant Science is available in addition to the main site. JSTOR Plant Science provides access to content such as plant type specimens, taxonomic structures, scientific literature, related materials and aimed at those researching, teaching, or studying botany, ecology and conservation studies; the materials on JSTOR Plant Science are contributed through the Global Plants Initiative and are accessible only to JSTOR and GPI members. Two partner networks are contributing to this: the African Plants Initiative, which focuses on plants from Africa, the Latin American Plants Initiative, which contributes plants from Latin America. JSTOR launched its Books at JSTOR program in November 2012, adding 15,000 current and backlist books to its site; the books are linked from citations in journal articles. In September 2014, JSTOR launched JSTOR Daily, an online magazine meant to bring academic research to a broader audience.
Posted articles are based on JSTOR entries, some entries provide the backstory to current events. JSTOR is licensed to academic institutions, public libraries, research institutions and schools. More than 7,000 institutions in more than 150 countries have access. JSTOR has been running a pilot program of allowing subscribing institutions to provide access to their alumni, in addition to current students and staff; the Alumni Access Program launched in January 2013. Individual subscriptions are available to certain journal titles through the journal publisher; every year, JSTOR blocks 150 million attempts by non-subscribers to read articles. Inquiries have been made about the possibility of making JSTOR open access. According to Harvard Law professor Lawrence Lessig, JSTOR had been asked "how much would it cost to make this available to the whole world, how much would we need to pay you? The answer was $250 million". In late 2010 and early 2011, Internet activist Aaron Swartz used MIT's data network to bulk-download a substantial portion of JSTOR's collection of academic journal articles.
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