Quasigroup

In mathematics, especially in abstract algebra, a quasigroup is an algebraic structure resembling a group in the sense that "division" is always possible. Quasigroups differ from groups mainly in that they need not be associative.

A quasigroup with an identity element is called a loop.

Definitions

There are at least two equivalent formal definitions of quasigroup. One defines a quasigroup as a set with one binary operation, and the other, from universal algebra, defines a quasigroup as having three primitive operations. We begin with the first definition.

A quasigroup (Q, ∗) is a set, Q, with a binary operation, ∗, (that is, a magma), obeying the Latin square property. This states that, for each a and b in Q, there exist unique elements x and y in Q such that both

hold. (In other words: Each element of the set occurs exactly once in each row and exactly once in each column of the quasigroup's multiplication table, or Cayley table. This property ensures that the Cayley table of a finite quasigroup is a Latin square.)

Loop (knot)

In reference to knots, loop may refer to:

References

Turn (biochemistry)

A turn is an element of secondary structure in proteins where the polypeptide chain reverses its overall direction. For beta turns go to Beta turn.

Definition

According to one definition, a turn is a structural motif where the C^α atoms of two residues separated by few (usually 1 to 5) peptide bonds are close (< 7 Å), while the residues do not form a secondary structure element such as an alpha helix or beta sheet with regularly repeating backbone dihedral angles. Although the proximity of the terminal C^α atoms usually correlates with formation of a hydrogen bond between the corresponding residues, a hydrogen bond is not a requirement in this turn definition. That said, in many cases the H-bonding and C^α-distance definitions are equivalent.

Types of turns

Turns are classified according to the separation between the two end residues:

In an α-turn the end residues are separated by four peptide bonds ().

In a β-turn (the most common form), by three bonds ().

In a γ-turn, by two bonds ().

Zoo Weekly

Zoo was a British (and formerly an Australian and South African) lads' magazine published weekly by Bauer Media Group in the United Kingdom. It was launched on 29 January 2004, and for a time was the UK's only men's weekly after the similar and rival magazine Nuts closed in April 2014.

On 17 November 2015, Zoo announced on its website that it would be suspending publication.

Zoo consisted of a mix of comedy news, sports commentary, photos of semi-naked women, jokes (of the pub joke style), an entertainments guide (covering TV, cinema, video/computer games and music), fashion/grooming and comical/rude pictures sent in by readers.

International editions

UK

Zoo was a weekly news magazine aimed at the male market. It was launched on 29 January 2004, as the second weekly men's magazine in the UK (the first being the similar and rival magazine; Nuts). The magazine was published by German company Bauer Media Group.

The Zoo website is a continuation of the magazine's content that also includes original articles, videos and photo galleries. Readers are also invited to create a profile and post pictures via the "Zoo Bloggers" section.

Zoo (CTrain)

Zoo is a stop on the Northeast Line (Route 202) of the CTrain light rail system in Calgary, Alberta. The station opened on April 27, 1985 as part of the original Northeast line. The station, which is located in the median of Memorial Drive Northeast, 2.5 km from the City Hall Interlocking, serves the Calgary Zoo, Telus Spark (science museum) as well as the community of Bridgeland.

Stylistically, the design of Zoo Station differs from the other stations in the CTrain system as it incorporates images of animals and dinosaurs. The station's center-loading platform is accessed via ramps leading up from a tunnel below Memorial Drive. The tunnel below Memorial Drive also houses several permanent zoo-related exhibits.

Although Calgary Transit does not operate a park-and-ride at this station, the Calgary Zoo has 500 spots available to LRT commuters for $5/day.

As part of Calgary Transit's plan to operate 4-car trains by the end of 2014, all 3-car platforms are being extended. Zoo station will also see new furnishings in addition to a platform extension. Construction started in early 2014 and lasted approximately 6 months.

Zoo (Patterson novel)

Zoo is a stand-alone science fiction thriller novel by James Patterson and Michael Ledwidge published in September 2012 and appeared on the New York Times best seller list.

Plot

The novel centers on Jackson Oz, who is an outcast among professional and academic ecologists and biologists. Oz has tried for years to get these scientists to listen to the data he has been collecting on the increasing numbers of mammal attacks on humans. He becomes so obsessed with this goal that he quits graduate school and devotes himself to full-time data collection and arguing his case. Finally, on a trip to Botswana, he survives an attack by a large band of male lions in which about 100 people are killed over a large area. He saves the life of ecologist Chloe Tousignant, and together they seek to warn the world that something has caused mammals of all types to band together in what seems to be an orchestrated effort to eliminate humans. The balance of the novel sees Oz gaining acceptance of his data, while world leaders take misguided actions to solve the problem, only to see even worse mammal attacks threaten the existence of man.