Monday, January 26, 2009

Zygosity


In genetics, zygosity refers to the similarity or dissimilarity of the DNA sequences in specific coding segments, or genes, on the homologous chromosomes of a zygote, or fertilized egg. The DNA sequence of any gene can vary among individuals in the population. The various forms of a gene are called alleles, and diploid organisms generally have two alleles for each gene, one on each of the two homologous chromosomes on which the gene is present. In diploid organisms, the alleles are inherited from the individual's parents, one from the male parent and one from the female. Zygosity in general is a description of whether those two alleles code for the same trait expression or different ones, but there are several specific applications of the term.

Monday, January 19, 2009

Cud

Cud is a portion of food that returns from a ruminant's stomach in the mouth to be chewed for the second time. More accurately, it is a bolus of semi-degraded food regurgitated from the reticulorumen of a ruminant. Cud is produced during the physical digestive process of rumination, or "chewing the cud". The idiomatic expression chewing one's cud means meditating or pondering.

Monday, January 12, 2009

Oceanography

Oceanography also called oceanology or marine science, is the branch of Earth science that studies the ocean. It covers a wide range of topics, including marine organisms and ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamics; plate tectonics and the geology of the sea floor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it: biology, chemistry, geology, meteorology, and physics.

Wednesday, January 07, 2009

Denim

Denim is a rugged cotton twill textile, in which the weft passes under two (twi- "double") or more warp fibers. This produces the familiar diagonal ribbing identifiable on the reverse of the fabric, which distinguishes denim from cotton duck. Denim has been in American usage since the late eighteenth century.The word comes from the name of a sturdy fabric called serge, originally made in Nîmes, France, by the Andre family. Originally called serge de Nîmes, the name was soon shortened to denim. Denim was traditionally colored blue with indigo dye to make blue "jeans," though "jean" then denoted a different, lighter cotton textile; the contemporary use of jean comes from the French word for Genoa, Italy (Gênes), where the first denim trousers were made.

A similarly woven traditional American cotton textile is the diagonal warp-striped hickory cloth that was once associated with railroadmen's overalls, in which blue or black contrasting with undyed white threads form the woven pattern. Hickory cloth was characterized as being as rugged as hickory wood—not to mention the fact that it was deemed to be worn mainly by "hicks"—although neither may be the origin of that term [from a nickname for "Richard"]. Records of a group of New Yorkers headed for the California gold fields in 1849 show that they took along four "hickory shirts" apiece. Hickory cloth would later furnish the material for some "fatigue" pantaloons and shirts in the American Civil War.

The word dungarees, to identify heavy cotton pants such as overalls, can be traced to a thick cotton country-made cloth, Dongari Kapar, which was sold in the quarter contiguous to the Dongari Killa, the fort of what was then known as Bombay (Hobson Johnson Dictionary). The word entered English with just this meaning in 1696 (OED). Dongri Fort was rebuilt in 1769 as Fort George, Bombay, where the first cotton mill was established in 1854. Dyed in indigo, the traditional cloth was used by Portuguese sailors and cut wide so that the legs could be swiftly rolled up when necessary. Thus, dungarees have a separate history.

Thursday, January 01, 2009

Puchezh-Katunki crater

Puchezh-Katunki is a meteor crater in the Chkalovsky District of Nizhny Novgorod Oblast in Volga Federal District, Russia. It is 80 km in diameter and is estimated to be 167 ± 3 million years old, placing it in the Middle Jurassic. The crater is not exposed to the surface, but appears as variation in the vegetation.