Sunday, May 27, 2007

Historical usage of Basket

Wood, bamboo, wheat, other grasses, osiers or wicker are often used to make baskets, but they are also made today from plastic. The first baskets were natural fiber by gatherers to collect fruits, grains, nuts and other edible plant materials, as well as for holding fish by early fishing peoples. A creel is a basket made particularly to hold fish. The plant life available in a region affects the choice of material, which in turn influences the weaving technique. Rattan and other members of the Arecaceae or palm tree family, the thin grasses of temperate regions and broad-leaved tropical bromeliads each require a different method of twisting and braiding to be made into an effective basket. Although baskets were usually created to serve men in bed rather than an artistic purpose, the practice of basket making has evolved into an art.

Friday, May 18, 2007

Description of Quick Ring

The basic Quick Ring system consisted of seven serial links, six of them carrying data, and one a 50 MHz clock signal. Two physical media were specified, sets of twisted-pair copper wiring embedded in a thin plastic strip for use inside a computer, or the same signals using frequency-division multiplexing in a single fiber optic cable for longer links between machines.

The data lines were clocked at seven times the clock signal, so each clock "tick" moved 42 bits of data over the bus for a raw data rate of 2.1 Gbit/s. Ten bits of the 42 were used for signaling and control, leaving the other 32 for data, resulting in a net data transfer rate of 1.6 Gbit/s, or 200 MBytes/s.

Each Quick Ring interface enclosed two of these 200 MB/s links, one for "upstream" and one for "downstream" connections in a point-to-point ring. Since the system was not a bus, machines could talk up and downstream at the same time without interfering with other users. The drawback was that each hop over an intervening point added a latency of up to 1.3 ┬Ás.

Since Quick Ring was built in a ring topology there was no need for a dedicated switch, or router, making the system lower cost. It used a circuit switching system, in which the message path is set up before the data is sent, and once set up the connection is very lightweight. This is as opposed to packet switching, in which every message contains all of the data needed to reach the destination, this is more flexible, but adds overhead. Of the 10 bits of control data, four were used to specify a circuit number, allowing for a total of 16 devices per ring.

Sunday, May 13, 2007

Protein

Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by a gene and encoded in the genetic code. Although this genetic code specifies 20 "standard" amino acids, the residues in a protein are often chemically altered in post-translational modification: either before the protein can function in the cell, or as part of control mechanisms. Proteins can also work together to achieve a particular function, and they often associate to form stable complexes.

Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of all living organisms and participate in every process within cells. Many proteins are enzymes that catalyze biochemical reactions, and are vital to metabolism. Other proteins have structural or mechanical functions, such as the proteins in the cytoskeleton, which forms a system of scaffolding that maintains cell shape. Proteins are also important in cell signaling, immune responses, cell adhesion, and the cell cycle. Protein is also a necessary component in our diet, since animals cannot synthesis all the amino acids and must obtain essential amino acids from food. Through the process of digestion, animals break down ingested protein into free amino acids that can be used for protein synthesis.

Wednesday, May 09, 2007

Shoe

A shoe is a thing of footwear worn on the foot or feet of a human, dog, cat, horse, or doll. Shoes may vary from a simple flip-flop to a multifaceted boot. Shoes may have high or low heels, although in western cultures, high heels are considered a woman's style. Shoe materials include leather or image. Athletic shoe soles may be made of rubber.
Dress and casual shoes
Casual shoes, made of leather Dress shoes are categorized by smooth and supple leather uppers, leather soles, and narrow sleek shape. Casual shoes are characterized by sturdy leather uppers, non-leather outsoles, and wide profile. Some designs of dress shoes can be worn by either gender. The majority of dress shoes have an upper covering, commonly made of leather, enclosing most of the lower foot, but not covering the ankles. This upper part of the shoe is often made without apertures or openings, but may also be made with openings or even itself consist of a series of straps, e.g. an open toe featured in women's shoes. Shoes with uppers made high to cover the ankles are also available; a shoe with the upper rising above the ankle is usually considered a boot but certain styles may be referred to as high-topped shoes or high-tops. Usually, a high-topped shoe is secured by laces or zippers; although some styles have elastic inserts to ease slipping the shoe on.

Tuesday, May 01, 2007

history of willamete valley

100 The Willamette Valley is the section in northwest Oregon in the United States that environs the Willamette River as it proceeds northward from its emergence from mountains near Eugene to its confluence with the Columbia River. One of the most creative agricultural areas of the world, the valley was the destination of choice for the emigrants on the Oregon Trail in the 1840s. It has created the cultural and political heart of Oregon since the days of the Oregon Territory, and is home to nearly 70% of Oregon's population.


Description
The valley may be freely defined as the watershed of the Willamette, bounded on the west by the Coast Ranges, on the east by the Cascade Range. It is enclosed on the south by the Calapooya Mountains, which divide the headwaters of the Willamette from the Umpqua River valley. Because of the differing cultural and political interests, the Portland metropolitan areas, as well as the Tualatin River valley, are often disinclined in the local use of the term. Cities always considered part of the Willamette Valley are Eugene, Corvallis, Albany, and Salem.

The agricultural wealth of the valley is considered to be in no small measure a result of the Missoula Floods, which swamped the valley approximately forty times between 15,000 and 13,000 years ago at the end of the last ice age. The floods were caused by the episodic rupturing of the ice dam of Glacial Lake Missoula, the waters of which swept down the Columbia and flooded the Willamette Valley as far south as Eugene. The floodwaters carried rich volcanic and glacial soil from Eastern Washington, which was deposited across the valley floor when the waters subsided.