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.

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 µs.

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.

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 synthesise 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.

Basket

A basket is a container which is usually constructed from stiff fibers, often made of willow. The top is either left open or the basket may be fitted with a lid.
Contents
1 chronological usage
2 contemporary usages
3 metaphorical and legendary usages
4 verandas of baskets
5 observe also
Historical usage
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.

Lens construction

The majority type of lenses are spherical lenses, which are fashioned from surfaces that have spherical curvature, that is, the front and back surfaces of the lens can be anticipated to be part of the surface of two spheres of given radii, R1 and R2, which are called the radius of curvature of each surface. The sign of R1 gives the form of the front surface of the lens: if R1 is positive, the surface is convex. If R1 is negative, the front surface is concave. If R1 is infinite, the surface is flat, or has zero curvature, and is said to be plane. The same is true for the back surface of the lens; apart from that the sign conversion is reversed: if R2 is positive, it is concave, and if R2 is negative, the back surface is convex. The line joining the centers of the spheres making up the lens surfaces is called the axis of the lens; in almost all cases the lens axis passes through the physical centre of the lens.

Lenses are divided by the bend of these two surfaces. A lens is biconvex if both surfaces are convex; similarly, a lens with two concave surfaces is biconcave. If one of the surfaces is flat, the lens is termed Plano-convex or Plano-concave depending on the curvature of the other surface. A lens with one convex and one concave side is named convex-concave, and in this case if both curvatures are equal it is a meniscus lens. If the lens is biconvex or Plano-convex, a collimated or parallel beam of light passing along the lens axis and through the lens will be converged to a spot on the axis, at a certain distance behind the lens. In this case, the lens is called a constructive or converging lens.

If the lens is biconcave or Plano-concave, a collimated beam of light passing through the lens is diverged; the lens is thus called a negative or diverging lens. The beam after passing through the lens appears to be emanating from a particular point on the axis in front of the lens; the detachment from this point to the lens is also known as the focal length, although it is negative with respect to the focal length of a converging lens.
If the lens is convex-concave, whether it is converging or diverging depends on the relative curvatures of the two surfaces. If the curvatures are equal, then the beam is neither converged nor diverged.