Tuesday, September 09, 2008

Foraging Foraging

Foraging Foraging theory is a branch of behavioral ecology that studies the foraging behavior of animals in response to the environment in which the animal lives. Foraging theory considers the foraging behavior of animals in reference to the payoff that an animal obtains from different foraging options. Foraging theory predicts that the foraging options that deliver the highest payoff, should be favored by foraging animals because it will have the highest fitness payoff.

Robert MacArthur, J M Emlen, and Eric Pianka, first proposed an optimal foraging theory in an independent paper in 1966. This theory argued that because of the key importance of successful foraging to an individual's survival, it should be possible to predict foraging behavior by using decision theory to determine the behavior that would be shown by an "optimal forager" - one with perfect knowledge of what to do to maximize usable food intake. While the behavior of real animals inevitably departs from that of the optimal forager, optimal foraging theory has proved very useful in developing hypotheses for describing real foraging behavior. Departures from optimality often help to identify constraints either in the animal's behavioral or cognitive repertoire, or in the environment, that had not previously been suspected. With those constraints identified, foraging behavior often does approach the optimal pattern even if it is not identical to it.

Thursday, September 04, 2008

Enterprise Architecture Framework

An Enterprise Architecture Framework (or Architecture Framework for short) defines how to organize the structure and views associated with an Enterprise Architecture. Because the discipline of Enterprise Architecture is so broad, and because the enterprises it describes tend to be large and complex, the models associated with the discipline also tend to be large and complex. To manage this scale and complexity, an Architecture Framework defines complementary projections of the enterprise model called Views, where each View is meaningful to different system stakeholders.

Monday, August 25, 2008

Acid dye

Acid dye is a member of a class of dye that is applied from an acidic solution. In the home or art studio, the acid used in the dyebath is often vinegar (acetic acid) or citric acid. The uptake rate of the dye is controlled with the use of sodium chloride.

In textiles, acid dyes are effective on protein fibers, i.e. animal hair fibers like wool, alpaca and mohair. They are also effective on silk. They are effective in dyeing the synthetic fiber nylon but of minimal interest in dyeing any other synthetic fibers.

Acid dyes are generally divided into three classes which depend on fastness requirements, level dyeing properties and economy. The classes overlap and generally depend on type of fiber to be coloured and also the process used.

Acid dyes are thought to fix to fibers by hydrogen bonding, Van der Waals forces and ionic bonding. They are normally sold as the Sodium salt therefore they are in solution anionic. Animal protein fibers and synthetic Nylon fibers contain many cationic sites therefore there is an attraction of anionic dye molecule to a cationic site on the fiber. The strength (fastness) of this bond is related to the desire/ chemistry of the dye to remain dissolved in water over fixation to the fiber.

Wednesday, August 20, 2008

Notable paleontologists

History includes a number of prominent paleontologists. Fossils were systematically studied in the 11th century by the Persian naturalist, Ibn Sina (known as Avicenna in Europe), in The Book of Healing (1027), and by the Chinese naturalist, Shen Kuo (1031-1095). In particular, Ibn Sina's theory on fossils was accepted by most naturalists in medieval Europe and the medieval Near East by the 16th century.

The modern discipline of paleontology begins in the 19th century, when Charles Darwin collected fossils of South American mammals during his trip on the Beagle and examined petrified forests in Patagonia. Mary Anning was a notable early paleontologist. She found several landmark fossils, in her home town of Lyme Regis. Although self-taught, she collected and described them in a very systematic way. William Buckland, Richard Owen, Gideon Mantell, Georges Cuvier and Thomas Huxley were important early pioneers, in the field of paleontology. Thomas Jefferson took a keen interest in mammoth bones. Edward Drinker Cope and Othniel Charles Marsh waged a famously fierce competition known as the Bone Wars in the late 19th century that involved some questionable practices, but which significantly advanced the understanding of the natural history of North America and vertebrate paleontology. Professor Earl Douglass of the Carnegie University in Pittsburgh, Pennsylvania, opened the fossil quarry protected today by Dinosaur National Monument in Utah. Douglass' fossils are in several Natural History Museums. Meanwhile, Baron Franz Nopcsa, a pioneer paleobiologist, argued that dinosaurs might have been both warm-blooded and ancestral to birds.

Besides looking at mammal teeth and unearthing penguin skeletons, George Gaylord Simpson played a crucial role in bringing together ideas from biology, paleontology and genetics, to help create the 'Modern Synthesis' of evolutionary biology. His book "Tempo and Mode" is a classic in the field. Prominent names in invertebrate paleontology include Steven M. Stanley, Stephen Jay Gould, David Raup, Rousseau H. Flower and Jack Sepkoski, who have done much to expand our understanding of long-term patterns in the evolution of life on earth. Large names in the field of paleoanthropology include Louis, Mary and Richard Leakey, Raymond Dart, Robert Broom, C.K. 'Bob' Brain, Kenneth Oakley, Robert Ardrey and Tim White. In recent times, Mongolian paleontologist Rinchen Barsbold has done much to expand our understanding of dinosaur and bird evolution. Paul Sereno of the University of Chicago has made several important dinosaur finds in areas such as the Sahara, where fossil hunting has been uncommon.

Wednesday, August 13, 2008

Wi-Fi Operational advantages

Wi-Fi allows LANs (Local Area Networks) to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.

2008, wireless network adapters are built into most modern laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in ever more devices. Wi-Fi has become widespread in corporate infrastructures.

Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards compatible. Wi-Fi is a global set of standards. Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world.

Wi-Fi is widely available in more than 220,000 public hotspots and tens of millions of homes and corporate and university campuses worldwide. WPA is not easily cracked if strong passwords are used and WPA2 encryption has no known weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video), and power saving mechanisms (WMM Power Save) improve battery operation.

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Tuesday, August 05, 2008

Nuclear fusion

In physics and nuclear chemistry, nuclear fusion is the process by which multiple atomic particles join together to form a heavier nucleus. It is accompanied by the release or absorption of energy. Iron and nickel nuclei have the largest binding energies per nucleon of all nuclei. The fusion of two nuclei lighter than iron generally releases energy while the fusion of nuclei heavier than iron absorbs energy; vice-versa for the reverse process, nuclear fission.

Nuclear fusion occurs naturally in stars. Artificial fusion in human enterprises has also been achieved, although not yet completely controlled. Building upon the nuclear transmutation experiments of Ernest Rutherford done a few years earlier, fusion of light nuclei (hydrogen isotopes) was first observed by Mark Oliphant in 1932, and the steps of the main cycle of nuclear fusion in stars were subsequently worked out by Hans Bethe throughout the remainder of that decade. Research into fusion for military purposes began in the early 1940s, as part of the Manhattan Project, but was not successful until 1952. Research into controlled fusion for civilian purposes began in the 1950s, and continues to this day.

Tuesday, July 29, 2008

Empathy

In phenomenology, empathy refers to the experience of another human body as another subjectivity: You see another body, but you immediately perceive another subject. In Husserl's original account, this was done by apperception built on the experiences of your own lived-body which you experience in a dual way, both as object (you can touch your own hand) and as your own subjectivity (you are being touched). This experience of your own body as your own subjectivity is then applied to the experience of another's body, which, through apperception, is constituted as another subjectivity. This experience of empathy is important in the phenomenological account of intersubjectivity.