Pea crab

The pea crab, Pinnotheres pisum, is a small crab in the family Pinnotheridae that lives as a parasite in oysters, clams, mussels, and other species of bivalves.

Description

Pea crabs are small crustaceans about the size of a pea or dime, with a "smooth dorsal surface of the carapace, or upper exoskeleton". The exoskeleton of males is hard and circular and has eyes and antennae extending from their fronts, and the chelipeds are more robust in males than in females, which have more elongated chelipeds. The bodies of the female pea crabs are often translucent and show the inner organs and gonads as yellow and red, with the males being a "more yellowish-grey with patches of brown".

Ecology

The relationship between the pea crab and its host is one of parasitism, rather than commensalism, since the host may be harmed by the crab's feeding activities. The pea crab solely relies on its host for food, safety, and oxygen.

Pea crabs have a variety of hosts, the most important of which are mollusks. The pea crab lives in the mantle cavity of these hosts. Other hosts, in addition to oysters, include sea urchins and sand dollars.Pinnotheres can be found inside sand dollars, in the rectum of sea cucumbers, in the tubes of parchment worms, in the burrows of mud shrimp, or in the gills of sea squirts.

Pea

The pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Pea pods are botanically fruit, since they contain seeds and developed from the ovary of a (pea) flower. The name is also used to describe other edible seeds from the Fabaceae such as the pigeon pea (Cajanus cajan), the cowpea (Vigna unguiculata), and the seeds from several species of Lathyrus.

P. sativum is an annual plant, with a life cycle of one year. It is a cool season crop grown in many parts of the world; planting can take place from winter to early summer depending on location. The average pea weighs between 0.1 and 0.36 grams. The immature peas (and in snow peas the tender pod as well) are used as a vegetable, fresh, frozen or canned; varieties of the species typically called field peas are grown to produce dry peas like the split pea shelled from the matured pod. These are the basis of pease porridge and pea soup, staples of medieval cuisine; in Europe, consuming fresh immature green peas was an innovation of Early Modern cuisine.

One Hot Minute

One Hot Minute is the sixth studio album by the American rock band Red Hot Chili Peppers, released on September 12, 1995, on Warner Bros. Records. The worldwide success of the band's previous album, Blood Sugar Sex Magik (1991), caused guitarist John Frusciante to become uncomfortable with their status, eventually quitting mid-tour in 1992.

One Hot Minute was the only album that guitarist Dave Navarro recorded with the band. His presence altered the Red Hot Chili Peppers' sound considerably. It contains fewer sexual themes than previous records and explores darker subject matters, such as drug use, depression, anguish, and grief. It also re-integrated use of heavy metal guitar riffs. Vocalist Anthony Kiedis, who had resumed addictions to cocaine and heroin in 1994 after being sober for more than five years, approached his lyricism with a reflective outlook on drugs and their harsh effects.

One Hot Minute was a commercial disappointment despite producing three hit singles and reaching number four on the Billboard 200 chart. It sold less than half as many copies as Blood Sugar Sex Magik and received much less critical acclaim. Navarro was ultimately fired from the band in 1998 due to creative differences.

Pea (disambiguation)

A pea is a small spherical seed or the seed-pod of various plants commonly used as a source of food, particularly Pisum sativum.

Pea or Peas may refer to:

See also

Crab

Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) (Greek: βραχύς / brachys = short,οὐρά / οura = tail), usually entirely hidden under the thorax. They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton and have a single pair of claws. Many other animals with similar names – such as hermit crabs, king crabs, porcelain crabs, horseshoe crabs and crab lice – are not true crabs.

Evolution

Crabs are generally covered with a thick exoskeleton, composed primarily of calcium carbonate, and armed with a single pair of chelae (claws). Crabs are found in all of the world's oceans, while many crabs live in fresh water and on land, particularly in tropical regions. Crabs vary in size from the pea crab, a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 metres (13 ft).

About 850 species of crab are freshwater, terrestrial or semi-terrestrial species; they are found throughout the world's tropical and semi-tropical regions. They were previously thought to be a monophyletic group, but are now believed to represent at least two distinct lineages, one in the Old World and one in the New World.

Crab (unit)

A Crab is a standard astrophotometrical unit for measurement of the intensity of Astrophysical X-ray sources. One Crab is defined as the intensity of the Crab Nebula at the corresponding X-ray photon energy.

The Crab Nebula, and the Crab Pulsar within it, is an intense space X-ray source. It is used as a standard candle in the calibration procedure of X-ray instruments in space. However, because of the Crab Nebula's variable intensity at different X-ray energies, conversion of the Crab to another units depends on the X-ray energy range of interest.

In the photon energy range from 2 to 10 keV, 1 Crab equals 2.4 · 10⁻⁸erg cm⁻²s⁻¹ = 15 keV cm⁻² s⁻¹ = 2.4 · 10⁻¹¹W m⁻². For energies greater than ~30 keV, the Crab Nebula becomes unsuitable for calibration purposes, as its flux can no longer be characterized by a single coherent model.

The unit mCrab, or milliCrab, is sometimes used instead of the Crab.

References

Crab (cipher)

In cryptography, Crab is a block cipher proposed by Burt Kaliski and Matt Robshaw at the first Fast Software Encryption workshop in 1993. Not really intended for use, Crab was developed to demonstrate how ideas from hash functions could be used to create a fast cipher.

Crab has an unusually large block size of 8192 bits. Its creators suggested using an 80-bit key, but the cipher could use any key size. The authors didn't specify an actual key schedule, only that the key is used to generate two large sets of subkeys: a permutation of the numbers 0 through 255, and an array of 2048 32-bit numbers. The block is divided into 256 32-bit subblocks, which are permuted at the beginning. Then the algorithm makes four passes over the data, each time applying one of four transformations adapted from MD5.

A brief note on the cryptanalysis of Crab is included in Markku-Juhani Saarinen's paper on block ciphers based on SHA-1 and MD5, published at FSE 2003. The author demonstrates a weakness in Crab that permits a distinguisher using no more than a dozen chosen plaintexts, and speculates that this can be converted into a full key-recovery attack using no more than 2¹⁶ chosen plaintexts. Such an attack would depend on the key schedule used.