Monday, December 15, 2008

Genetics


Genetics (from Ancient Greek genetikos, “genitive” and that from genesis, “origin”), a discipline of biology, is the science of heredity and variation in living organisms.The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the process of inheritance, only began with the work of Gregor Mendel in the mid-nineteenth century. Although he did not know the physical basis for heredity, Mendel observed that organisms inherit traits in a discrete manner—these basic units of inheritance are now called genes.
DNA, the molecular basis for inheritance. Each strand of DNA is a chain of nucleotides, matching each other in the center to form what look like rungs on a twisted ladder.

Genes correspond to regions within DNA, a molecule composed of a chain of four different types of nucleotides—the sequence of these nucleotides is the genetic information organisms inherit. DNA naturally occurs in a double stranded form, with nucleotides on each strand complementary to each other. Each strand can act as a template for creating a new partner strand—this is the physical method for making copies of genes that can be inherited.

The sequence of nucleotides in a gene is translated by cells to produce a chain of amino acids, creating proteins—the order of amino acids in a protein corresponds to the order of nucleotides in the gene. This is known as the genetic code. The amino acids in a protein determine how it folds into a three-dimensional shape; this structure is, in turn, responsible for the protein's function. Proteins carry out almost all the functions needed for cells to live. A change to the DNA in a gene can change a protein's amino acids, changing its shape and function: this can have a dramatic effect in the cell and on the organism as a whole.

Wednesday, December 03, 2008

Grain milk


Grain milk is a milk substitute made from fermented grain or from flour. Grain milk can be made from oats, spelt, rice, rye, einkorn wheat or quinoa.

Grain milk looks very similar to cow's milk. It has a lower protein content and a higher carbohydrate content than cow's milk. Just as cow's milk is often fortified with Vitamin D, which it naturally lacks, grain milks may have calcium and some vitamins (especially B12) added to them.

Grain milk is low in saturated fat and contains no lactose, which is beneficial for those who are lactose intolerant. Grain milk also lacks milk protein, making it suitable for vegans and people with milk allergies.

Flavored grain milk can come in plain, vanilla, chocolate or a variety of other flavors. Like unflavored grain milk, it is often available with added nutrients. There are also grain milk cream and desserts available.

Friday, November 28, 2008

Horticulture

In the area of horticulture, Defra has policy responsibility for work on horticultural production and marketing, potatoes and hops. Along with other UK Agriculture Departments, Defra administers schemes for growers, including the Producer Organisation (Fresh Fruit and Vegetables) Aid Scheme.Growers may also be eligible for payments under the Single Payment Scheme.


Defra's horticultural policy responsibilities extend to the following EU regimes:
* fresh and processed fruit and vegetables and bananas
* flowers and plants
* hops

Part of this responsibility includes attending EU Management Committees. These are meetings attended by EU Member States whose responsibility it is to give an opinion on proposals made by the Commission for the management of the regimes. Further information on Management Committees can be found on the Europa website.Defra commissions a variety of research which has relevance to the industry. Defra also sponsors the National Fruit Collection at Brogdale in Kent.

Wednesday, November 19, 2008

Tonicity

Tonicity is a measure of blood capacity or effective osmolality in cell biology. Osmolality and osmolarity are properties of a particular solution, independent of any membrane. Tonicity is the base measurment for complex compounds with provides immunity to the body, and is equal to the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across that membrane. Tonicity, also, depends on solute permemability (permeant solutes do not affect tonicity; impermeant solutes do affect tonicity). Tonicity is generally classified in three ranges; hypertonicity, hypotonicity and isotonicity. Hypertonic, isotonic and hypotonic solutions are defined in reference to a cell membrane by comparing the tonicity of the solution with the tonicity within the cell

Wednesday, November 12, 2008

Inner planet Venus

Venus (0.7 AU) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere. No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions.

Monday, November 03, 2008

OpenGL 2.1

OpenGL 2.1 was released on August 2, 2006 and is backward compatible with all prior OpenGL versions. OpenGL 2.1 incorporates the following functionality:

  • Shading Language revision 1.20 (GLSL)
  • to specify and query non-square matrix uniforms for use with the OpenGL Shading Language
  • Pixel buffer objects for efficient image transfers to and from buffer objects for commands such as glTexImage2D and glReadPixels.

This functionality corresponds to the ARB_pixel_buffer_object extension.

  • sRGB texture formats.

This functionality corresponds to the EXT_texture_sRGB extension.

Thursday, October 30, 2008

Cognition


Cognition is a concept used in different ways by different disciplines, but is generally accepted to mean the process of awareness or thought. For example, in psychology, it refers to an information processing view of an individual's psychological functions. Other interpretations of the meaning of cognition link it to the development of concepts; individual minds, groups, organizations, and even larger coalitions of entities, can be modelled as societies which cooperate to form concepts. The autonomous elements of each 'society' would have the opportunity to demonstrate emergent behavior in the face of some crisis or opportunity. Cognition can also be interpreted as "understanding and trying to make sense of the world".

Tuesday, October 21, 2008

Steel lattice


The steel lattice is the most widespread form of construction. It provides great strength, low wind resistance and economy in the use of materials. Such structures are usually triangular or square in cross-section.

When built as a stayed mast, usually the whole mast is parallel-sided. One exception is the Blaw-Knox type.

When built as a tower, the structure may be parallel-sided or taper over part or all of its height. When constructed of several sections which taper exponentially with height, in the manner of the Eiffel Tower, the tower is said to be an Eiffelized one. The Crystal Palace tower in London is an example.

Sunday, October 12, 2008

Single Message Authorisation/Clearing


Some financial networks operate a single message solution, in which a transaction is authorised and cleared via the same message.

A transaction will be authorised via a pre-authorisation step, where the merchant requests the issuer to reserve an amount on the cardholder's account for a specific time, followed by completion, where the merchant requests an amount blocked earlier with a pre-authorisation. This transaction flow in two steps is often used in businesses such as hotels and car rental where the final amount is not known, and the pre-authorisation is made based on an estimated amount. Completion may form part of a settlement process, typically performed at the end of the day when the day's completed transactions are submitted. All these messages will be sent "on-line" from the merchant acquirer to the issuing bank.

Monday, September 29, 2008

Bluetooth 1.2


  • Faster Connection and Discovery
  • Adaptive frequency-hopping spread spectrum (AFH), which improves resistance to radio frequency interference by avoiding the use of crowded frequencies in the hopping sequence.
  • Higher transmission speeds in practice, up to 721 kbit/s, as in 1.1.
  • Extended Synchronous Connections (eSCO), which improve voice quality of audio links by allowing retransmissions of corrupted packets, and may optionally increase audio latency to provide better support for concurrent data transfer.
  • Host Controller Interface (HCI) support for three-wire UART.
  • Ratified as IEEE Standard 802.15.1-2005.

Tuesday, September 23, 2008

VOR


The next major advance in "beam based" navigation system was the use of two signals that varied not in sound, but in phase. In these systems, known as VHF omnidirectional range, or VOR, a single master signal is sent out continually from the station, and a highly directional second signal is sent out that varies in phase 30 times a second compared to the master. This signal is timed so that the phase varies as the secondary antenna spins, such that when the antenna is 90 degrees from north, the signal is 90 degrees out of phase of the master. By comparing the phase of the secondary signal to the master, the angle can be determined without any physical motion in the receiver. This angle is then displayed in the cockpit of the aircraft, and can be used to take a fix just like the earlier RDF systems, although it is, in theory, easier to use and more accurate.

Tuesday, September 16, 2008

Sight


Sight or vision is the ability of the brain and eye to detect electromagnetic waves within the visible range (light) interpreting the image as "sight." There is disagreement as to whether this constitutes one, two or three senses. Neuroanatomists generally regard it as two senses, given that different receptors are responsible for the perception of colour (the frequency of photons of light) and brightness (amplitude/intensity - number of photons of light). Some argue[citation needed] that stereopsis, the perception of depth, also constitutes a sense, but it is generally regarded as a cognitive (that is, post-sensory) function of brain to interpret sensory input and to derive new information. The inability to see is called blindness.

Monday, September 08, 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.

Tuesday, September 02, 2008

Panic disorder


In panic disorder, a person suffers from brief attacks of intense terror and apprehension that cause trembling and shaking, confusion, dizziness, nausea, difficulty breathing, and feelings of impending doom or a situation that would be embarrassing. One who is often plagued by sudden bouts of intense anxiety might be said to be afflicted by this disorder. The American Psychiatric Association (2000) defines a panic attack as fear or discomfort that arises abruptly and peaks in 10 minutes or less, and can occasionally last hours.

Although panic attacks sometimes seem to occur out of nowhere, they generally happen after frightening experiences, prolonged stress, or even exercise. Many people who have panic attacks (especially their first one) think they are having a heart attack and often end up at the doctor or emergency room. Even if the tests all come back normal the person will still worry, with the physical manifestations of anxiety only reinforcing their fear that something is wrong with their body. Heightened awareness (hypervigilance) of any change in the normal function of the human body will be noticed and interpreted as a possible life threatening illness by an individual suffering from panic attacks.

Normal changes in heartbeat, such as when climbing a flight of stairs will be noticed by a panic sufferer and lead them to think something is wrong with their heart or they are about to have another panic attack. Some begin to worry excessively and even quit jobs or refuse to leave home to avoid future attacks. Panic disorder can be diagnosed when several apparently spontaneous attacks lead to a persistent concern about future attacks.

Monday, August 25, 2008

Protected mode and supervisor mode


Modern CPUs support something called dual mode operation. CPUs with this capability use two modes: protected mode and supervisor mode, which allow certain CPU functions to be controlled and affected only by the operating system kernel. Here, protected mode does not refer specifically to the 80286 (Intel's x86 16-bit microprocessor) CPU feature, although its protected mode is very similar to it. CPUs might have other modes similar to 80286 protected mode as well, such as the virtual 8086 mode of the 80386 (Intel's x86 32-bit microprocessor or i386).

However, the term is used here more generally in operating system theory to refer to all modes which limit the capabilities of programs running in that mode, providing things like virtual memory addressing and limiting access to hardware in a manner determined by a program running in supervisor mode. Similar modes have existed in supercomputers, minicomputers, and mainframes as they are essential to fully supporting UNIX-like multi-user operating systems.

When a computer first starts up, it is automatically running in supervisor mode. The first few programs to run on the computer, being the BIOS, bootloader and the operating system have unlimited access to hardware. However when the operating system passes control to another program, it can place the CPU into protected mode.

In protected mode, programs may have access to a more limited set of the CPU's instructions. A user program may leave protected mode only by triggering an interrupt, causing control to be passed back to the kernel. In this way the operating system can maintain exclusive control over things like access to hardware and memory.

The term "protected mode resource" generally refers to one or more CPU registers, which contain information that the running program isn't allowed to alter. Attempts to alter these resources generally causes a switch to supervisor mode.

Tuesday, August 19, 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.

Monday, August 11, 2008

Tagged Image File Format


Tagged Image File Format (abbreviated TIFF) is a file format for storing images, including photographs and line art. It is now under the control of Adobe Systems. Originally created by the company Aldus for use with what was then called "desktop publishing", the TIFF format is widely supported by image-manipulation applications, by publishing and page layout applications, by scanning, faxing, word processing, optical character recognition and other applications. Adobe Systems, which acquired Aldus, now holds the copyright to the TIFF specification. TIFF has not had a major update since 1992, though several Aldus/Adobe technical notes have been published with minor extensions to the format, and several specifications, including TIFF/EP, have been based on the TIFF 6.0 specification.

The TIFF is a flexible, adaptable file format for handling images and data within a single file, by including the header tags (size, definition, image-data arrangement, applied image compression) defining the image's geometry. For example, a TIFF can be a container file holding compressed JPEG and RLE (run-length encoding) images. A TIFF also can include a vector-based Clipping path (outlines, croppings, image frames). The ability to store image data in a lossless format makes the TIFF file a useful image archive, because, unlike standard JPEG files, the TIFF using lossless compression (or none) may be edited and re-saved without losing image compression; other TIFF options are layers and pages.

Although the currently accepted standard format, when the TIFF was introduced, its extensibility provoked compatibility problems. Programmers were free to specify new tags and options — but not every implemented program supported every tag created. Resultantly, the TIFF became the lowest common denominator image file. Today, the most TIFF images and readers remain based upon uncompressed 32-bit CMYK or 24-bit RGB images.

Monday, August 04, 2008

Eukaryotic cells

Eukaryotic cells consist of cell membrane, organelles which represent the functional components for storage, excretion, digestion and nucleus (centre of the cell), it contains all the vital information needed by the cell or the whole organism to function, grow and reproduce.
Eukaryotic cells are found in humans, plants and animals, also algae, and protozoa. Eukaryotic cells have both a cellular membrane and a nuclear membrane. Eukaryotic genome is more complex than that of prokaryotes and distributed among multiple chromosomes.

  • Mitosis: The division of the parent nucleus into two daughter nuclei, separating the duplicated genome into two sets, each identical to the parent cell's genome.
  • Cytokinesis: The pinching and division of the cell membrane and cytoplasm, separating the recently divided nuclei, the organelles, and other cellular components.
  • Meiosis: The division of the nucleus in sex cells that reduces the diploid number of chromosomes to a haploid number in order to facilitate sexual reproduction.
Examples of cell division in multicellular eukariotic organisms include repair, growth, and development. An injury or wound is healed when the cells exposed by the injury divide at an excellerated rate until they come into contact with other cells. After this the cells return to a more typical division rate. Cell division causes an organism to grow as long as the rate of cell division exceeds normal cell death. As cells divide and become more numerous they are located in more diverse physical and chemical environments. These variations in local conditions influence the cells to alter gene expression causing the cells to differentiate and become more specialized allowing an organism to develop

Monday, July 28, 2008

Modernism

Many advocates of capitalism agreed with Marx's analysis of capitalism as a process of continual change, but, unlike Marx, believed and hoped that capitalism would essentially go on forever.

Thus, by the beginning of the 20th century, two opposing schools of thought - Marxism and liberalism - believed in the possibility and the desirability of continual change and improvement. Marxists strongly opposed capitalism and the liberals strongly supported it, but the one concept they could both agree on was modernism.

Modernism is a trend of thought which affirms the power of human beings to make, improve and reshape their society, with the aid of scientific knowledge, technology and practical experimentation. It reaches its extreme limits with the Russian Revolution and the third Chinese revolution, inspired by Marxist ideology. Here, people claimed such confidence in the ability to change their world for the better, which they thought that, in a relatively short time, largely illiterate peasants could begin to build a just, egalitarian and socialist order in a conscious way, armed with science and technology.

Monday, July 21, 2008

Alphabets

An alphabet is a small set of symbols, each of which roughly represents or historically represented a phoneme of the language. In a perfectly phonological alphabet, the phonemes and letters would correspond perfectly in two directions: a writer could predict the spelling of a word given its pronunciation, and a speaker could predict the pronunciation of a word given its spelling. As languages often evolve independently of their writing systems, and writing systems have been borrowed for languages they were not designed for, the degree to which letters of an alphabet correspond to phonemes of a language varies greatly from one language to another and even within a single language.

In most of the alphabets of the Mid-East, only consonants are indicated, or vowels may be indicated with optional diacritics. Such systems are called abjads. In most of the alphabets of India and Southeast Asia, vowels are indicated through diacritics or modification of the shape of the consonant. These are called abugidas. Some abugidas, such as Ethiopic and Cree, are learned by children as syllabaries, and so are often called "syllabics". However, unlike true syllabaries, there is not an independent glyph for each syllable.

Sometimes the term "alphabet" is restricted to systems with separate letters for consonants and vowels, such as the Latin alphabet. Because of this use, Greek is often considered to be the first alphabet.