Chicken

The chicken (Gallus gallus domesticus) is a domesticated fowl, a subspecies of the red junglefowl. As one of the most common and widespread domestic animals, with a population of more than 19 billion in 2011, there are more chickens in the world than any other species of bird or domestic animal. Humans keep chickens primarily as a source of food, consuming both their meat and their eggs.

Genetic studies have pointed to multiple maternal origins in Southeast-, East-, and South Asia, but with the clade found in the Americas, Europe, the Middle East and Africa originating in the Indian subcontinent. From India, the domesticated chicken was imported to Lydia in western Asia Minor, and to Greece by the fifth century BC. Fowl had been known in Egypt since the mid-15th century BC, with the "bird that gives birth every day" having come to Egypt from the land between Syria and Shinar, Babylonia, according to the annals of Thutmose III.

Terminology

In the UK and Ireland adult male chickens over the age of one year are primarily known as cocks, whereas in America, Australia and Canada they are more commonly called roosters. Males less than a year old are cockerels.Castrated roosters are called capons (surgical and chemical castration are now illegal in some parts of the world). Females over a year old are known as hens and younger females as pullets although in the egg-laying industry, a pullet becomes a hen when she begins to lay eggs at 16 to 20 weeks of age. In Australia and New Zealand (also sometimes in Britain), there is a generic term chook /ˈtʃʊk/ to describe all ages and both sexes. The young are called chicks and the meat is called chicken.

Fitting subgroup

In mathematics, especially in the area of algebra known as group theory, the Fitting subgroup F of a finite group G, named after Hans Fitting, is the unique largest normal nilpotent subgroup of G. Intuitively, it represents the smallest subgroup which "controls" the structure of G when G is solvable. When G is not solvable, a similar role is played by the generalized Fitting subgroup F^*, which is generated by the Fitting subgroup and the components of G.

For an arbitrary (not necessarily finite) group G, the Fitting subgroup is defined to be the subgroup generated by the nilpotent normal subgroups of G. For infinite groups, the Fitting subgroup is not always nilpotent.

The remainder of this article deals exclusively with finite groups.

The Fitting subgroup

The nilpotency of the Fitting subgroup of a finite group is guaranteed by Fitting's theorem which says that the product of a finite collection of normal nilpotent subgroups of G is again a normal nilpotent subgroup. It may also be explicitly constructed as the product of the p-cores of G over all of the primes p dividing the order of G.

Network layer

In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers, whereas the data link layer is responsible for media access control, flow control and error checking.

Functions

The network layer provides the functional and procedural means of transferring variable-length data sequences from a source to a destination host via one or more networks, while maintaining the quality of service functions.

Functions of the network layer include:

Within the service layering semantics of the OSI network architecture, the network layer responds to service requests from the transport layer and issues service requests to the data link layer.

Protocols

Session layer

In the seven-layer OSI model of computer networking, the session layer is layer 5.

The session layer provides the mechanism for opening, closing and managing a session between end-user application processes, i.e., a semi-permanent dialogue. Communication sessions consist of requests and responses that occur between applications. Session-layer services are commonly used in application environments that make use of remote procedure calls (RPCs).

An example of a session-layer protocol is the OSI protocol suite session-layer protocol, also known as X.225 or ISO 8327. In case of a connection loss this protocol may try to recover the connection. If a connection is not used for a long period, the session-layer protocol may close it and re-open it. It provides for either full duplex or half-duplex operation and provides synchronization points in the stream of exchanged messages.

Other examples of session layer implementations include Zone Information Protocol (ZIP) – the AppleTalk protocol that coordinates the name binding process, and Session Control Protocol (SCP) – the DECnet Phase IV session-layer protocol.

Hen

Hen commonly refers to a female animal: a chicken, other poultry, game bird, or lobster. It is also a slang term for a woman.

Hen or Hens may also refer to:

Places

Norway

United Kingdom

Other

Other uses

Hen (pronoun)

Hen (Swedish: [hɛn]) is a gender-neutral personal pronoun in Swedish intended as an alternative to the gender-specific hon ("she") and han ("he"). It can be used when the gender of a person is not known or when it is not desirable to specify them as either a "she" or "he". The word was first proposed in 1966, and again in 1994, with reference to the Finnish hän, a personal pronoun that is gender-neutral, since Finnish does not have grammatical genders. However, it did not receive widespread recognition until around 2010, when it began to be used in some books, magazines and newspapers, and provoked media debates and controversy over feminism, gender neutrality, and parenting. In July 2014 it was announced that hen would be included in Svenska Akademiens ordlista, the official glossary of the Swedish Academy.

It is currently treated as neologism by Swedish manuals of style. Major newspapers like Dagens Nyheter have recommended against its usage, though some journalists still use it. The Swedish Language Council has not issued any specific proscriptions against the use of hen, but recommends the inflected forms hens ("her(s)/his") as the possessive form and the object form hen ("her/him") over henom, which also occurs. Hen has two basic usages: as a way to avoid a stated preference to either gender; or as a way of referring to individuals who are transgender, who prefer to identify themselves as belonging to a third gender or who reject the division of male/female gender roles on ideological grounds, including genderqueer.

Hen (name)

Hen is both a surname and a masculine given name. Notable people with the name Hen or Hens include:

Surname:

Given name:

See also