Monday, January 26, 2009

Abiotic stress In Animals


For animals, the most stressful of all the abiotic stressors is heat. This is because many species are unable to regulate their internal body temperature. Even in the species that are able to regulate their own temperature, it is not always a completely accurate system. Temperature determines metabolic rates, heart rates, and other very important factors within the bodies of animals, so an extreme temperature change can easily distress the animal’s body. Animals can respond to extreme heat, for example, through natural heat acclimation or by burrowing into the ground to find a cooler space. It is also possible to see in animals that a high genetic diversity is beneficial in providing resiliency against harsh abiotic stressors. This acts as a sort of stock room when a species is plagued by the perils of natural selection. A variety of galling insects are among the most specialized and diverse herbivores on the planet, and their extensive protections against abiotic stress factors have helped the insect in gaining that position of honor.

Monday, January 19, 2009

Llama

The llama (Lama glama) is a South American camelid, widely used as a pack animal by the Incas and other natives of the Andes mountains. In South America llamas are still used as beasts of burden, as well as for the production of fiber and meat.

The height of a full-grown, full-size llama is between 5.5 feet (1.6 meters) to 6 feet (1.8 m) tall at the top of the head. They can weigh between approximately 280 pounds (127 kilograms) and 450 pounds (204 kilograms). At birth, a baby llama (called a cria) can weigh between 20 pounds (9 kilograms) to 30 pounds (14 kilograms). Llamas are very social animals and like to live with other llamas as a herd. Overall, the fiber produced by a llama is very soft and is naturally lanolin free. Llamas are intelligent and can learn simple tasks after a few repetitions. When using a pack, llamas can carry about 25%–30% of their body weight for several miles.

Llamas appear to have originated from the central plains of North America about 40 million years ago. They migrated to South America and Asia about 3 million years ago. By the end of the last ice age (10,000–12,000 years ago) camelids were extinct in North America. As of 2007, there were over 7 million llamas and alpacas in South America and, due to importation from South America in the late 20th century, there are now over 100,000 llamas and 6,500–7,000 alpacas in the US and Canada.

Monday, January 12, 2009

Arctic Ocean

  • Amundsen Gulf
  • Baffin Bay
  • Barents Sea
  • Beaufort Sea
  • Bering Sea
  • Chukchi Sea
  • Davis Strait
  • Denmark Strait
  • East Siberian Sea
  • Greenland Sea
  • Hudson Bay
  • James Bay
  • Kara Sea
  • Kara Strait
  • Labrador Sea
  • Laptev Sea
  • Lincoln Sea
  • Norwegian Sea
  • White Sea

Wednesday, January 07, 2009

Flax


Flax (is a member of the genus Linum in the family Linaceae. It is native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent This is called as Jawas/Javas or Alashi in Marathi. Flax was extensively cultivated in ancient Egypt. (New Zealand flax is not related to flax, but was named after it as both plants are used to produce fibres.)

Flax is an erect annual plant growing to 1.2 m tall, with slender stems. The leaves are glaucous green, slender lanceolate, 20–40 mm long and 3 mm broad. The flowers are pure pale blue, 15–25 mm diameter, with five petals; they can also be bright red. The fruit is a round, dry capsule 5–9 mm diameter, containing several glossy brown seeds shaped like an apple pip, 4–7 mm long.

In addition to referring to the plant itself, "flax" may refer to the unspun fibres of the flax plant.

Thursday, January 01, 2009

Chicxulub crater


The Chicxulub Crater is an ancient impact crater buried underneath the Yucatán Peninsula in Mexico.Its center is located near the town of Chicxulub, after which the crater is named—as well as the rough translation of the Mayan name, "the tail of the devil."The crater is more than 180 kilometers (110 mi) in diameter, making the feature one of the largest confirmed impact structures in the world; the impacting bolide that formed the crater was at least 10 km (6 mi) in diameter.

The crater was discovered by Glen Penfield, a geophysicist who had been working in the Yucatán while looking for oil during the late 1970s. Evidence for the impact origin of the crater includes shocked quartz, a gravity anomaly, and tektites in surrounding areas. The age of the rocks and isotope analysis show that this impact structure dates from the end of the Cretaceous Period, roughly 65 million years ago. The impact associated with the crater is implicated in causing the extinction of the dinosaurs as suggested by the K–T boundary, although some critics argue that the impact was not the sole reasonand others debate whether there was a single impact or whether the Chicxulub impactor was one of several that may have struck the Earth at around the same time. Recent evidence suggests that the impactor may have been a piece of a much larger asteroid that broke up in a collision in distant space more than 160 million years ago.

Thursday, December 25, 2008

Human languages

Human languages are usually referred to as natural languages, and the science of studying them falls under the purview of linguistics. A common progression for natural languages is that they are considered to be first spoken, then written, and then an understanding and explanation of their grammar is attempted.

Languages live, die, move from place to place, and change with time. Any language that ceases to change or develop is categorized as a dead language. Conversely, any language that is in a continuous state of change is known as a living language or modern language.

Making a principled distinction between one language and another is usually impossible. For instance, there are a few dialects of German similar to some dialects of Dutch. The transition between languages within the same language family is sometimes gradual (see dialect continuum).

Some like to make parallels with biology, where it is not possible to make a well-defined distinction between one species and the next. In either case, the ultimate difficulty may stem from the interactions between languages and populations. (See Dialect or August Schleicher for a longer discussion.)

The concepts of Ausbausprache, Abstandsprache and Dachsprache are used to make finer distinctions about the degrees of difference between languages or dialects.

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.