Thursday, December 27, 2007

Computer hardware

Computer hardwareis the physical part of a computer, including the digital circuitry, as distinguished from the computer software that executes within the hardware. The hardware of a computer is infrequently changed, in comparison with software and data, which are "soft" in the sense that they are readily created, modified or erased on the computer. Firmware is a special type of software that rarely, if ever, needs to be changed and so is stored on hardware devices such as read-only memory (ROM) where it is not readily changed (and is, therefore, "firm" rather than just "soft").

Most computer hardware is not seen by normal users. It is in embedded systems in automobiles, microwave ovens, electrocardiograph machines, compact disc players, and other devices. Personal computers, the computer hardware familiar to most people, form only a small minority of computers (about 0.2% of all new computers produced in 2003). See Market statistics.

Tuesday, December 18, 2007

Western blotting

Antibodies to most proteins can be created by injecting small amounts of the protein into an animal such as a mouse, rabbit, sheep, or donkey (polyclonal antibodies)or produced in cell culture (monoclonal antibodies). These antibodies can be used for a variety of analytical and preparative techniques.

In western blotting, proteins are first separated by size, in a thin gel sandwiched between two glass plates in a technique known as SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis). The proteins in the gel are then transferred to a PVDF, nitrocellulose, nylon or other support membrane. This membrane can then be probed with solutions of antibodies. Antibodies that specifically bind to the protein of interest can then be visualized by a variety of techniques, including coloured products, chemiluminescence, or autoradiography.

Analogous methods to western blotting can also be used to directly stain specific proteins in cells and tissue sections. However, these immunostaining methods are typically more associated with cell biology than molecular biology.

The terms "western" and "northern" are jokes: The first blots were with DNA, and since they were done by Ed Southern, they came to be known as Southerns. Patricia Thomas, inventor of the RNA blot, which became known as a "northern", actually didn't use the term.

Tuesday, December 11, 2007

Mobile media

Whilst we commonly think of mobile media as being essentially a new, 21st century phenomenon, it is important to note that it is not an entirely new concept. Indeed the mobility and portability of media or as Paul Levinson calls it in his book entitled Cellphone “the media-in-motion business” has been a process in the works ever since the “first time someone thought to write on a tablet that could be lifted and hauled – rather than on a cave wall, a cliff face, a monument that usually was stuck in place, more or less forever”. Levinson’s statement here brings into focus contemporary mobile media devices such as mobile phones and PDA’s which are commonly represented and thought of as not only entirely new and original products of mobility but also the only source of portable media from which we can obtain information and communicate with one another.

While mobile phone and PDA’s independent technologies and functions may be new and innovative (in relation to changes and improvements in media capabilities in respect to their function what they can do when and where and what they look like, in regard to their size and shape) the need and desire to access and use media devices regardless of where we are in the world has been around for centuries. Indeed Paul Levinson remarks in regard to telephonic communication that it was “intelligence and inventiveness applied to our need to communicate regardless of where we may be, led logically and eventually to telephones that we carry in our pockets”. Levinson in his book goes on to state that the book, transistor radio, Kodak camera are also bearers of portable information.

Thursday, December 06, 2007

Weapons delivery

Nuclear weapons delivery—the technology and systems used to bring a nuclear weapon to its target—is an important aspect of nuclear weapons relating both to nuclear weapon design and nuclear strategy. Additionally, developing and maintaining delivery options is among the most resource-intensive aspects of nuclear weapons: according to one estimate, deployment of nuclear weapons accounted for 57% of the total financial resources spent by the United States in relation to nuclear weapons since 1940.

Historically the first method of delivery, and the method used in the two nuclear weapons actually used in warfare, is as a gravity bomb, dropped from bomber aircraft. This method is usually the first developed by countries as it does not place many restrictions on the size of the weapon, and weapon miniaturization is something which requires considerable weapons design knowledge. It does, however, limit the range of attack, the response time to an impending attack, and the number of weapons which can be fielded at any given time. Additionally, specialized delivery systems are usually not necessary; especially with the advent of miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers, allowing an air force to use its current fleet with little or no modification.