Thursday, December 25, 2008

Language


A language is a dynamic set of sensory symbols of communication and the elements used to manipulate them. Language can also refer to the use of such systems as a general phenomenon. Strictly speaking, language is considered to be an exclusively human mode of communication. Although other animals make use of quite sophisticated communicative systems, sometimes casually referred to as animal language, none of these are known to make use of all of the properties that linguists use to define language.

In Western Philosophy, language has long been closely associated with reason, which is also a uniquely human way of using symbols. In Ancient Greek philosophical terminology, the same word, logos, was used as a term for both language or speech and reason, and the philosopher Thomas Hobbes used the English word "speech" so that it similarly could refer to reason, as will be discussed below. More commonly though, the English word "language", derived ultimately from lingua, Latin for tongue, typically refers only to expressions of reason which can be understood by other people, most obviously by speaking.

Monday, December 15, 2008

Cell nucleus


In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, or kernel) is a membrane-enclosed organelle found in all eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome. The function of the nucleus is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression.

The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and separates its contents from the cellular cytoplasm, and the nuclear lamina, a meshwork within the nucleus that adds mechanical support, much like the cytoskeleton supports the cell as a whole. Because the nuclear membrane is impermeable to most molecules, nuclear pores are required to allow movement of molecules across the envelope. These pores cross both of the membranes, providing a channel that allows free movement of small molecules and ions. The movement of larger molecules such as proteins is carefully controlled, and requires active transport regulated by carrier proteins. Nuclear transport is crucial to cell function, as movement through the pores is required for both gene expression and chromosomal maintenance.

Although the interior of the nucleus does not contain any membrane-bound subcompartments, its contents are not uniform, and a number of subnuclear bodies exist, made up of unique proteins, RNA molecules, and particular parts of the chromosomes. The best known of these is the nucleolus, which is mainly involved in the assembly of ribosomes. After being produced in the nucleolus, ribosomes are exported to the cytoplasm where they translate mRNA.

Wednesday, December 03, 2008

Soy milk Preparation


Soy milk can be made from whole soybeans or full-fat soy flour. The dry beans are soaked in water overnight or for a minimum of 3 hours or more depending on the temperature of the water. The rehydrated beans then undergo wet grinding with enough added water to give the desired solids content to the final product. The ratio of water to beans on a weight basis should be about 10:1. The resulting slurry or purée is brought to a boil in order to improve its nutritional value by heat inactivating soybean trypsin inhibitor, improve its flavor and to sterilize the product. Heating at or near the boiling point is continued for a period of time, 15-20 minutes, followed by the removal of an insoluble residue (soy pulp fiber or okara) by filtration.

There is a simple yet profound difference between traditional Chinese and Japanese soy milk processing: the Chinese method boils the filtrate (soy milk) after a cold filtration, while the Japanese method boils the slurry first, followed by hot filtration of the slurry. The latter method results in a higher yield of soy milk but requires the use of an anti-foaming agent or natural defoamer during the boiling step. Bringing filtered soy milk to a boil avoids the problem of foaming. It is generally opaque, white or off-white in color, and approximately the same consistency as cow's milk.

For all raw soybean protein products heat is necessary to destroy the activity of the protease inhibitors naturally present in the soybean. The pancreas naturally secretes proteases to digest a protein meal. Eating raw soybeans on a regular basis causes the pancreas to hypersecrete, leading to benign tumors of the pancreas (just like exercise causes muscles to develop hypertrophy). This is why the above heating to properly prepare soymilk is essential for fatty acid breakdown.

Friday, November 28, 2008

Protect San José’s creeks and rivers

Water that enters our City storm drain system flows untreated into the nearest creek or river and ultimately to the San Francisco Bay. Stormwater runoff, in the form of rain or irrigation water, collects pollutants by flowing over sidewalks, driveways, curbs, and landscaping.

Common pollutants - such as trash, oil, soap, paint, copper, nickel, mercury, and pesticides - can degrade, or impair, water quality in our local creeks and rivers. Less commonly recognized pollutants, such as leaves or landscape clippings, can reduce the amount of oxygen available in the creeks for fish which makes it difficult for fish to live. Even soil and sediment can impair water quality, both by degrading spawning habitat in the creeks and by carrying pollutants such as copper, nickel and other heavy metals that readily bind to sediment. Rivers carrying excessive sediment and other pollutants can significantly reduce spawning habitat for fish, which in turn impacts other wildlife. These pollutants, individually and cumulatively, adversely affect fish, plants and wildlife that live in and depend on the City’s rivers and creeks.

Also, it’s the law. Water quality in creeks, rivers, storm drains and the Bay is protected and regulated by State laws like the California Porter-Cologne Water Quality Control Act, Federal laws, such as the Clean Water Act, as well as local ordinances.

Wednesday, November 19, 2008

Ontology


On an individual being level, these questions are studied by the separate fields above, but are also more integrated into cognitive ontology of various kinds. This challenges the older linguistically dependent views of ontology, wherein one could debate being, perceiving, and doing, with no cognizance of innate human limits, varying human lifeways, and loyalties that may let a being "know" something (see qualia) that for others remains very much in doubt.

On the level of an individual mind, an emergent behavior might be the formation of a new concept, 'bubbling up' from below the conscious level of the mind. A simple way of stating this is that beings preserve their own attention and are at every level concerned with avoiding interruption and distraction. Such cognitive specialization can be observed in particular in language, with adults markedly less able to hear or say distinctions made in languages to which they were not exposed in youth.

Monday, November 03, 2008

Structure


Structure is a fundamental and sometimes intangible notion covering the recognition, observation, nature, and stability of patterns and relationships of entities. From a child's verbal description of a snowflake, to the detailed scientific analysis of the properties of magnetic fields, the concept of structure is an essential foundation of nearly every mode of inquiry and discovery in science, philosophy, and art.

A structure defines what a system is made of. It is a configuration of items. It is a collection of inter-related components or services. The structure may be a hierarchy (a cascade of one-to-many relationships) or a network featuring many-to-many relationships.

Thursday, October 30, 2008

Symptoms of brain tumors


Symptoms of brain tumors may depend on two factors: tumor size (volume) and tumor location. The time point of symptom onset in the course of disease correlates in many cases with the nature of the tumor ("benign", i.e. slow-growing/late symptom onset, or malignant, fast growing/early symptom onset).

Many low-grade (benign) tumors can remain asymptomatic (symptom-free) for years and they may accidentally be discovered by imaging exams for unrelated reasons (such as a minor trauma).

New onset of epilepsy is a frequent reason for seeking medical attention in brain tumor cases.

Large tumors or tumors with extensive perifocal swelling edema inevitably lead to elevated intracranial pressure (intracranial hypertension), which translates clinically into headaches, vomiting (sometimes without nausea), altered state of consciousness (somnolence, coma), dilatation of the pupil on the side of the lesion (anisocoria), papilledema (prominent optic disc at the funduscopic examination). However, even small tumors obstructing the passage of cerebrospinal fluid (CSF) may cause early signs of increased intracranial pressure. Increased intracranial pressure may result in herniation (i.e. displacement) of certain parts of the brain, such as the cerebellar tonsils or the temporal uncus, resulting in lethal brainstem compression. In young children, elevated intracranial pressure may cause an increase in the diameter of the skull and bulging of the fontanelles.

Depending on the tumor location and the damage it may have caused to surrounding brain structures, either through compression or infiltration, any type of focal neurologic symptoms may occur, such as cognitive and behavioral impairment, personality changes, hemiparesis, hypesthesia, aphasia, ataxia, visual field impairment, facial paralysis, double vision, tremor etc. These symptoms are not specific for brain tumors - they may be caused by a large variety of neurologic conditions (e.g. stroke, traumatic brain injury). What counts, however, is the location of the lesion and the functional systems (e.g. motor, sensory, visual, etc.) it affects.

Tuesday, October 21, 2008

Breadnut


The breadnut (Brosimum alicastrum) is a Brosimum tree species under the Moraceae family of flowering plants, whose other genera include fig and mulberries. Other common names for the plant include the Maya nut and ramón (particularly in Spanish-speaking regions). The plant is also known by a range of names in indigenous Mesoamerican and other languages, including but not limited to: ojoche, ojite, ojushte, ujushte, ujuxte, capomo, mojo, ox, iximche and masica.

The breadnut fruit disperses on the ground in March and April and has a large seed covered by a thin, citrus-flavored orange-colored skin favored by a number of forest creatures. More importantly, the large seed which is enveloped by the tasty skin is an edible ‘nut’ that can be leached and ground into a meal for porridge or flatbread. Ramon is nutritious and has value as a food source, and formed a part of the diet of the pre-Columbian Maya of the lowlands region in Mesoamerica, although to what extent has been a matter of some debate among Maya historians and archaeologists.

It was planted by the Maya civilization two thousand years ago and it has been claimed to have been a staple food in the Maya diet, although other research has downplayed its significance. In the modern era it has been neglected as a source of nutrition and has often been characterised as a famine food

Monday, October 13, 2008

Mobile Telephone System


The Mobile Telephone System (MTS) was one of the earliest mobile telephone standards. It was operator assisted both directions, meaning that if you were called from a land line the call would be routed to a mobile operator, who would route it to your phone. Similarly, to make an outbound call you had to go through the mobile operator, who would ask you for your mobile number and the number you were calling, and then would place the call.

This service originated with the Bell System, and was first used in St. Louis on June 17, 1946. The original equipment weighed 80 pounds, and there were initially only 3 channels for all the users in the metropolitan area, later more licenses were added bringing the total to 32 channels across 3 bands (See IMTS frequencies). This service was used at least into the 1980s in large portions of North America.

This protocol was replaced by Improved Mobile Telephone Service (IMTS).

Monday, September 29, 2008

Bluetooth low energy


On June 12, 2007, Nokia and Bluetooth SIG announced that Wibree will be a part of the Bluetooth specification, being an ultra-low power Bluetooth technology.Expected use cases include watches displaying Caller ID information, sports sensors monitoring your heart rate during exercise, plus medical devices. The Medical Devices Working Group is also creating a medical devices profile and associated protocols to enable this market. Battery life for devices using Bluetooth low energy technology is designed to last up to one year.

Tuesday, September 23, 2008

IPv6 private addresses


Just as IPv4 reserves addresses for private or internal networks, there are blocks of addresses set aside in IPv6 for private addresses. In IPv6, these are referred to as unique local addresses (ULA). RFC 4193 sets aside the routing prefix fc00::/7 for this block. The addresses include a 40-bit pseudorandom number that minimize the risk of address collisions if sites merge or packets are misrouted.

Early designs (RFC 3513) used a different block for this purpose (fec0::), dubbed site-local addresses. However, the definition of what constituted "sites" remained unclear, and the poorly defined address structure created ambiguities for routing. The address range specification was abandoned and must no longer be used in new systems.

Addresses starting with fe80: — called link-local addresses — are routable only in the local link area. The addresses are assigned automatically by the operating system's IP layer for each network interface. This provides instant network connectivity for any IPv6 host and means that if several hosts connect to a common hub or switch, they have an instant communication path via their link-local IPv6 address.

Tuesday, September 16, 2008

Kinesthetic sense


Proprioception, the kinesthetic sense, provides the parietal cortex of the brain with information on the relative positions of the parts of the body. Neurologists test this sense by telling patients to close their eyes and touch the tip of a finger to their nose. Assuming proper proprioceptive function, at no time will the person lose awareness of where the hand actually is, even though it is not being detected by any of the other senses. Proprioception and touch are related in subtle ways, and their impairment results in surprising and deep deficits in perception and action.

Monday, September 08, 2008

Pillbox

Dug-in guard posts (with loopholes through which to fire guns) and made from concrete are also known as 'pillboxes'. The originally jocular name arose from their perceived similarity to the cylindrical boxes in which medical pills were once sold.They are in effect a trench firing step hardened to protect against small-arms fire and grenades and raised to improve the field of fire.

Their use seems to have developed during the period of the First World War when defence in depth using the Machine Gun Corps was being perfected. However, most of those seen in Britain, having been left over from the 1940 invasion scare, are designed for use by riflemen rather than for machine gunners. The concrete nature of pillboxes means that they are a feature of prepared positions and their original use is likely to have been in the Hindenburg Line. This is likely to have been the time when they acquired their incongruous English name. The Oxford English Dictionary's earliest record of the use of the word pillbox in connection with a defensive post is from 13 September 1917, after the German withdrawal onto the Hindenburg Line.


Pillboxes are often camouflaged in order to conceal their location and to maximize the element of surprise. They may be part of a trench system, form an interlocking line of defence with other pillboxes by providing covering fire to each other (defence in depth), or they may be placed to guard strategic structures such as bridges and jetties.


Many pillboxes were built before WWII in the Czech Republic in defence against the German invasion of Czechoslovakia. None of these were actually used in the end, since the German military met no resistance when invading the country because it was effectively forced to capitulate as a result of Allies annexing the country's border areas and handing them to Germany. The Japanese also made use of pillboxes in their fortifications of Iwo Jima.

Tuesday, September 02, 2008

Human-computer interaction


Human–computer interaction (HCI) is the study of interaction between people (users) and computers. It is often regarded as the intersection of computer science, behavioral sciences, design and several other fields of study. Interaction between users and computers occurs at the user interface (or simply interface), which includes both software and hardware, for example, general-purpose computer peripherals and large-scale mechanical systems, such as aircraft and power plants. The following definition is given by the Association for Computing Machinery

"Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them."

Because human-computer interaction studies a human and a machine in conjunction, it draws from supporting knowledge on both the machine and the human side. On the machine side, techniques in computer graphics, operating systems, programming languages, and development environments are relevant. On the human side, communication theory, graphic and industrial design disciplines, linguistics, social sciences, cognitive psychology, and human performance are relevant. Engineering and design methods are also relevant. Due to the multidisciplinary nature of HCI, people with different backgrounds contribute to its success. However, due to the different value systems of its diverse members, the collaboration can be challenging

Monday, August 25, 2008

Device drivers


A device driver is a specific type of computer software developed to allow interaction with hardware devices. Typically this constitutes an interface for communicating with the device, through the specific computer bus or communications subsystem that the hardware is connected to, providing commands to and/or receiving data from the device, and on the other end, the requisite interfaces to the operating system and software applications. It is a specialized hardware-dependent computer program which is also operating system specific that enables another program, typically an operating system or applications software package or computer program running under the operating system kernel, to interact transparently with a hardware device, and usually provides the requisite interrupt handling necessary for any necessary asynchronous time-dependent hardware interfacing needs.

The key design goal of device drivers is abstraction. Every model of hardware (even within the same class of device) is different. Newer models also are released by manufacturers that provide more reliable or better performance and these newer models are often controlled differently. Computers and their operating systems cannot be expected to know how to control every device, both now and in the future. To solve this problem, OSes essentially dictate how every type of device should be controlled. The function of the device driver is then to translate these OS mandated function calls into device specific calls. In theory a new device, which is controlled in a new manner, should function correctly if a suitable driver is available. This new driver will ensure that the device appears to operate as usual from the operating systems' point of view for any person.

Tuesday, August 19, 2008

Demographics


Demographics or demographic data refers to selected population characteristics as used in government, marketing or opinion research, or the demographic profiles used in such research. Note the distinction from the term "demography" Commonly-used demographics include race, age, income, disabilities, mobility (in terms of travel time to work or number of vehicles available), educational attainment, home ownership, employment status, and even location. Distributions of values within a demographic variable, and across households, are both of interest, as well as trends over time. Demographics are frequently used in economic and marketing research.

Demographic trends describes the changes in demographics in a population over time. For example, the average age of a population may increase. It may decrease as well as certain restrictions may be in place, for instance like in China if the population is high.

The term demographics as a noun is often used erroneously in place of demography, the study of human population, its structure and change. Although there is no absolute delineation, demography focuses on population structure, processes and dynamics, whereas demographics is most often used in the fields of media studies, advertising, marketing, and polling, and should not be used interchangeably with the term "demography" or (more broadly) "population studies

Monday, August 11, 2008

Lecithin


Lecithin is any of a group of yellow-brownish fatty substances occurring in animal and plant tissues, and in egg yolk, composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids (e.g., phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol). However, lecithin is sometimes used as a synonym for pure phosphatidylcholine, a phospholipid that is the major component of its phosphatide fraction. It may be isolated either from egg yolk or from soy beans, from which it is extracted chemically (using hexane) or mechanically.

It has low solubility in water. In aqueous solution its phospholipids can form either liposomes, bilayer sheets, micelles, or lamellar structures, depending on hydration and temperature. This results in a type of surfactant that is usually classified as amphoteric.
Thus far, the only proven benefit and suggested use is for those taking niacin to treat high cholesterol. Niacin treatment can deplete choline, necessitating an increased amount of lecithin or choline in the diet.

Egg-derived lecithin may be a concern for those following some specialized diets. Egg lecithin is not a concern for those on low-cholesterol diets, but, if not purified before being used as a food ingredient, it could significantly raise the overall cholesterol content of the food. Consumer Product companies should clearly indicate the source of lecithin to help consumers.

For observant Jews under Kashrut, it is considered pareve, neutral, e.g., may be mixed with both meat and dairy.[citation needed] However, soy derived lecithin is considered by some to be kitniyot and prohibited on Passover.[citation needed] For most Muslims, lecithin or any other derivatives from plants, egg yolks or animals are allowed.[citation needed] There is no general agreement among vegetarians concerning egg-derived lecithin, but since it is animal-derived, Jains, strict vegetarians, vegans choose not to consume it.

Monday, August 04, 2008

Embryophyte

The embryophytes are the most familiar group of plants. They include trees, flowers, ferns, mosses, and various other green land plants. All are complex multicellular eukaryotes with specialized reproductive organs. With very few exceptions, embryophytes obtain their energy through photosynthesis (that is, by absorbing light); and they synthesize their food from carbon dioxide. Embryophyta may be distinguished from chlorophyll-using multicellular algae by having sterile tissue within the reproductive organs. Furthermore, embryophytes are primarily adapted for life on land, although some are secondarily aquatic. Accordingly, they are often called land plants or terrestrial plants.

Embryophytes developed from complex green algae (Chlorophyta) during the Paleozoic era. The Charales or stoneworts appear to be the best living illustration of that developmental step. These alga-like plants undergo an alternation between haploid and diploid generations (respectively called gametophytes and sporophytes). In the first embryophytes, however, the sporophytes became very different in structure and function, remaining small and dependent on the parent for their entire brief life. Such plants are informally called 'bryophytes'. They include three surviving groups:

  • Bryophyta (mosses)
  • Anthocerotophyta (hornworts)
  • Marchantiophyta (liverworts)

All of the above 'bryophytes' are relatively small and are usually confined to moist environments, relying on water to disperse their spores. Other plants, better adapted to terrestrial conditions, appeared during the Silurian period. During the Devonian period, they diversified and spread to many different land environments, becoming the vascular plants or tracheophytes. Tracheophyta have vascular tissues or tracheids, which transport water throughout the body, and an outer layer or cuticle that resists drying out. In most vascular plants, the sporophyte is the dominant individual, and develops true leaves, stems, and roots, while the gametophyte remains very small.

Many vascular plants, however, still disperse using spores. They include two extant groups:

  • Lycopodiophyta (clubmosses)
  • Pteridophyta (ferns, whisk ferns, and horsetails)
Other groups, which first appeared towards the end of the Paleozoic era, reproduce using desiccation-resistant capsules called seeds. These groups are accordingly called spermatophytes or seed plants. In these forms, the gametophyte is completely reduced, taking the form of single-celled pollen and ova, while the sporophyte begins its life enclosed within the seed. Some seed plants may even survive in extremely arid conditions, unlike their more water-bound precursors. The seed plants include the following extant groups:

  • Cycadophyta (cycads)
  • Ginkgophyta (ginkgo)
  • Pinophyta (conifers)

* Gnetophyta (gnetae)

* Magnoliophyta (flowering plants)

The first four groups are referred to as gymnosperms, since the embryonic sporophyte is not enclosed until after pollination. In contrast, among the flowering plants or angiosperms, the pollen has to grow a tube to penetrate the seed coat. Angiosperms were the last major group of plants to appear, developing from gymnosperms during the Jurassic period, and then spreading rapidly during the Cretaceous. They are the predominant group of plants in most terrestrial biomes today.

Note that the higher-level classification of plants varies considerably. Some authors have restricted the kingdom Plantae to include only embryophytes, others have given them various names and ranks. The groups listed here are often considered divisions or phyla, but have also been treated as classes, and they are occasionally compressed into as few as two divisions. Some classifications, indeed, consider the term Embryophyta at the superphylum (superdivision) level, and include Land Plants and some Charophyceae in a subkingdom named Streptophyta.

On a microscopic level, embryophyte cells remain very similar to those of green algae. They are eukaryotic, with a cell wall composed of cellulose and plastids surrounded by two membranes. These usually take the form of chloroplasts, which conduct photosynthesis and store food in the form of starch, and characteristically are pigmented with chlorophylls a and b, generally giving them a bright green color. Embryophytes also generally have an enlarged central vacuole or tonoplast, which maintains cell turgor and keeps the plant rigid. They lack flagella and centrioles except in certain gametes.

Monday, July 28, 2008

Marxism and Humanism

This trend of thinking is powerfully developed in the thought of Karl Marx (a student of Hegel's thought) and his secular historical materialism. With splendid rhetoric, Marx describes the mid-19th century condition in the Communist Manifesto as follows:

"The bourgeoisie cannot exist without constantly revolutionizing the instruments of production, and thereby the relations of production, and with them the whole relations of society. Conservation of the old modes of production in unaltered form, was, on the contrary, the first condition of existence for all earlier industrial classes. Constant revolutionizing of production, uninterrupted disturbance of all social conditions, everlasting uncertainty, and agitation distinguish the bourgeois epoch from all earlier ones. All fixed, fast frozen relations, with their train of ancient and venerable prejudices and opinions, are swept away, all new-formed ones become antiquated before they can ossify. All that is solid melts into air, all which is holy is profaned, and man is at last compelled to face with sober senses his real condition of life and his relations with his kind."

The capitalist era in history is understood here very radically as a process of continual change, in which the growth of markets dissolve all fixities in human life. This is an almost absolute rejection of the conservative ethos, according to which nothing really changes in human life. Marxism further states that capitalism, in its quest for higher profits and new markets, will inevitably sow the seeds of its own destruction. Marxists believe that, in the future, capitalism will be replaced by socialism and eventually communism.

Monday, July 21, 2008

White Nile

The White Nile (Arabic: النيل الأبيض, transliterated: an-Nīl al-Ābyadˤ) is a river of Africa, one of the two main tributaries of the Nile, the other being the Blue Nile. In the strict meaning, "White Nile" refers to the river formed at Lake No at the confluence of the Bahr al Jabal and Bahr el Ghazal rivers. In the wider sense, "White Nile" refers to the approximately 3700 kilometers (2300 miles) of rivers draining from Lake Victoria into the White Nile proper. It may also, depending on the speaker, refer to the headwaters of Lake Victoria.

The 19th century search by Europeans for the source of the Nile was mainly focused on the White Nile, which disappeared into the depths of what was then known as "Darkest Africa". The discovery of the source of the White Nile thus came to symbolise European penetration of unknown jungle.

Tuesday, July 15, 2008

Tephritidae

Tephritidae is one of two fly families referred to as "fruit flies." Tephritidae does not include the biological model organisms of the genus Drosophila, which is often called the "common fruit fly". Drosophila is, instead, the type genus of the second "fruit fly" family, Drosophilidae. There are nearly 5,000 described species of tephritid fruit fly, categorized in almost 500 genera. Description, recategorization, and genetic analysis are constantly changing the taxonomy of the fruit fly family.

Tephritid fruit flies are of major importance in agriculture. Some have negative effects, some positive. Various species of fruit fly cause damage to fruit and other plant crops. The genus Bactrocera is of worldwide notoriety for its destructive impact on agriculture. The olive fruit fly (B. oleae), for example, feeds on only one plant: the wild or commercially cultivated olive. It has the capacity to ruin 100% of an olive crop by damaging the fruit. On the other hand, some fruit flies are used as agents of biological control, thereby reducing the populations of pest species. Several species of the fruit fly genus Urophora have been shown to be effective agents against rangeland-destroying noxious weeds such as starthistles and knapweeds.

Most fruit flies lay their eggs in plant tissues, where the larvae find their first food upon emerging. The adults usually have a very short lifespan. Some live for less than a week.

Fruit flies use an open circulatory system as their cardiovascular system.

Their behavioral ecology is of great interest to biologists. Some fruit flies have extensive mating rituals or territorial displays. Many are brightly colored and visually showy. Some fruit flies show Batesian mimicry, bearing the colors and markings of dangerous insects such as wasps because it helps the fruit flies to avoid predators; the flies, of course, lack stingers.

Sunday, July 06, 2008

Six kingdoms

In the years around 1980 there was an emphasis on phylogeny and redefining the kingdoms to be monophyletic groups, groups made up of relatively closely related organisms. The Animalia, Plantae, and Fungi were generally reduced to core groups of closely related forms, and the others placed into the Protista. Based on RNA studies Carl Woese divided the prokaryotes (Kingdom Monera) into two kingdoms, called Eubacteria and Archaebacteria. Carl Woese attempted to establish a Three Primary Kingdom (or Urkingdom) system in which Plants, Animals, Protista, and Fungi were lumped into one primary kingdom of all eukaryotes. The Eubacteria and Archaebacteria made up the other two urkingdoms. The initial use of "six Kingdom systems" represents a blending of the classic Five Kingdom system and Woese's Three Kingdom system. Such six Kingdom systems have become standard in many works.

A variety of new eukaryotic kingdoms were also proposed, but most were quickly invalidated, ranked down to phyla or classes, or abandoned. The only one which is still in common use is the kingdom Chromista proposed by Cavalier-Smith, including organisms such as kelp, diatoms, and water moulds. Thus the eukaryotes are divided into three primarily heterotrophic groups, the Animalia, Fungi, and Protozoa, and two primarily photosynthetic groups, the Plantae (including red and green algae) and Chromista. However, it has not become widely used because of uncertainty over the monophyly of the latter two kingdoms.

Woese stresses genetic similarity over outward appearances and behaviour, relying on comparisons of ribosomal RNA genes at the molecular level to sort out classification categories. A plant does not look like an animal, but at the cellular level, both groups are eukaryotes, having similar subcellular organization, including cell nuclei, which the Eubacteria and Archaebacteria do not have. More importantly, plants, animals, fungi, and protists are more similar to each other in their genetic makeup at the molecular level, based on rRNA studies, than they are to either the Eubacteria or Archaebacteria. Woese also found that all of the eukaryotes, lumped together as one group, are more closely related, genetically, to the Archaebacteria than they are to the Eubacteria. This means that the Eubacteria and Archaebacteria are separate groups even when compared to the eukaryotes. So, Woese established the Three-domain system, clarifying that all the Eukaryotes are more closely genetically related compared to their genetic relationship to either the bacteria or the archaebacteria, without having to replace the "six kingdom systems" with a three kingdom system. The Three Domain system is a "six kingdom system" that unites the eukaryotic kingdoms into the Eukarya Domain based on their relative genetic similarity when compared to the Bacteria Domain and the Archaea Domain. Woese also recognized that the Protista Kingdom is not a monophyletic group and might be further divided at the level of Kingdom. Others have divided the Protista Kingdom into the Protozoa and the Chromista, for instance.

Sunday, June 29, 2008

bacteriophage

A bacteriophage (from 'bacteria' and Greek phagein, 'to eat') is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, phage.

Typically, bacteriophages consist of an outer protein hull enclosing genetic material. The genetic material can be ssRNA (single stranded RNA), dsRNA, ssDNA, or dsDNA between 5 and 500 kilo base pairs long with either circular or linear arrangement. Bacteriophages are much smaller than the bacteria they destroy - usually between 20 and 200 nm in size.

Phages are estimated to be the most widely distributed and diverse entities in the biosphere. Phages are ubiquitous and can be found in all reservoirs populated by bacterial hosts, such as soil or the intestines of animals. One of the densest natural sources for phages and other viruses is sea water, where up to 9×108 virions per milliliter have been found in microbial mats at the surface, and up to 70% of marine bacteria may be infected by phages.

They have been used for over 60 years as an alternative to antibiotics in the former Soviet Union and Eastern Europe. They are seen as a possible therapy against multi drug resistant strains of many bacteria.

Sunday, June 22, 2008

Algae

Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many of the distinct organs found in land plants. Though the prokaryotic cyanobacteria (commonly referred to as blue-green algae) were traditionally included as "algae" in older textbooks, many modern sources regard this as outdated and restrict the term algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group they do not represent a single evolutionary direction or line, but a level or grade of organization that may have developed several times in the early history of life on Earth.

Algae lack the various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. They are distinguished from protozoa in that they are photosynthetic. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus.

All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a byproduct of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria.

Sunday, June 15, 2008

Mail transfer agent

A mail transfer agent (MTA) (also called a mail transport agent, message transfer agent, or smtpd (short for SMTP daemon)), is a computer program or software agent that transfers electronic mail messages from one computer to another.

The term mail server is also used to mean a computer acting as an MTA that is running the appropriate software. The term mail exchanger (MX), in the context of the Domain Name System formally refers to an IP address assigned to a device hosting a mail server, and by extension also indicates the server itself.

An MTA receives mail from another MTA (relaying), from a mail user agent (MUA), thus acting as a mail submission agent (MSA), or from an MSA that got the mail from an MUA. The MTA works behind the scenes, while the user usually interacts with the MUA. Every time an MTA receives an e-mail, it will add a "Received:" trace header field to the top of the message. In this way, there is a record of which MTAs handled the e-mail and in which order. Upon final delivery, the "Return-Path:" header will also be added to record the return path.

The delivery of e-mail to a user's mailbox typically takes place via a mail delivery agent (MDA); many MTAs have basic MDA functionality built in, but a dedicated MDA like procmail can provide more sophistication.

According to one survey, sendmail, Microsoft Exchange Server, Postfix, and Exim together control over 85% of market share for SMTP service. Another survey suggests a more balanced playing field, though it included hosted email services such as Postini.

Sunday, June 08, 2008

Post trance

As an alternative evolution some artists have attempted to fuse trance with other genres such as drum'n'bass. Others have experimented with more minimalist sounds. Frustrated, extreme versions of trance have mutated through gabba into fringe genres of "hard trance" or "hardstyle" overlapping with hardcore and terrorcore.

Trance more loyal to its roots has begun to rear its head on the internet with the abundance of legal music download sites - including the likes of Juno Download, and Beatport, - enabling enthusiasts to avoid having to track down hard to find vinyl by downloading mp3s and uncompressed wavs, updated on a weekly basis. As a result, both commercial and progressive trance now have a much more global, if not chart-bound, presence, with big-draw artists such as Tiësto, ATB, Markus Schulz, Armin van Buuren, BT, Paul van Dyk, Ferry Corsten, Above & Beyond, Paul Oakenfold, Enigma, Schiller, Solarstone and the US's Christopher Lawrence and George Acosta able to maintain their esteemed positions while upcoming producers and DJs can also breakthrough into the public domain.

Monday, June 02, 2008

Lymphatic circulation

Unlike the cardiovascular system, the lymphatic system is not closed and has no central pump. Lymph movement occurs with low pressure due to peristalsis, valves, and the milking action of skeletal muscles. Like veins, lymph travels through vessels in one way only, due to semilunar valves. This depends mainly on the movement of skeletal muscles to squeeze fluid through them, especially near the joints. Rhythmic contraction of the vessel walls through movements may also help draw fluid into the smallest lymphatic vessels, capillaries. Tight clothing can restrict this, thus reducing the removal of wastes and allowing them to accumulate. If tissue fluid builds up the tissue will swell; this is called edema. As the circular path through the body's system continues, the fluid is then transported to progressively larger lymphatic vessels culminating in the right lymphatic duct (for lymph from the right upper body) and the thoracic duct (for the rest of the body); both ducts drain into the circulatory system at the right and left subclavian veins. The system collaborates with white blood cells in lymph nodes to protect the body from being infected by cancer cells, fungi, viruses or bacteria. This is known as a secondary circulatory system.

Wednesday, May 28, 2008

Types of water

Liquid water in motionWater can appear in three phases. Water takes many different forms on Earth: water vapor and clouds in the sky; seawater and rarely icebergs in the ocean; glaciers and rivers in the mountains; and aquifers in the ground.

Water can dissolve many different substances, giving it different tastes and odors. In fact, humans and other animals have developed senses to be able to evaluate the potability of water: animals generally dislike the taste of salty sea water and the putrid swamps and favor the purer water of a mountain spring or aquifer. Humans also tend to prefer cold water rather than lukewarm, as cold water is likely to contain fewer microbes. The taste advertised in spring water or mineral water derives from the minerals dissolved in it, as pure H2O is tasteless. As such, purity in spring and mineral water refers to purity from toxins, pollutants, and microbes.

Tuesday, May 27, 2008

Understanding the Context

Many different methods of communication are possible on the Internet; some use specific software and all involve text and/or graphics.

* Some activities take place in real-time while others allow for a delayed reply.

* Discussion areas may be public or exist for a particular group of people.

* Information can either be broadcast or targeted at a particular user.

As the technology develops, and users and providers become more proficient, the boundaries between the different Internet services are blurred. For example, email is used in chat rooms, web pages include discussion areas and newsgroups can have files attached.

Each Internet service has its own educational value, risks, and recommended ways of dealing with problems, and these are detailed in the following pages. They are not exhaustive and many apply across Internet services. Schools should consider the sum of the advice in these guidelines across all areas.

Thursday, May 22, 2008

Overview of the Click Thinking Pack

Schools and government initiatives are encouraging the educational use of the Internet right across the curriculum and young people are taking readily to this way of learning and communicating.

At the same time, the media tends to focus on the rare occasions when use of the Internet causes distress. The Scottish Executive believes that young people need to be protected and informed; and that those responsible for them, whether teachers, parents or other careers, should be aware of the issues involved.

Previous Scottish Executive Education Department (SEED) publications in this area have dealt with the need to protect pupils from misuse of computers (Information Ethics) and to understand copyright implications (Copyright and Ethics in a Digital Age).

This booklet focuses on personal safety and wellbeing. It attempts to clarify potential risks and to empower Internet users in schools so that they can keep themselves safe. Those who manage Scottish schools, and all teachers, whether responsible for a primary class or for teaching a subject, will find policy guidelines and background information which will prepare our pupils to take their safe and well-earned place in the Digital Age.

Much of the advice in these guidelines will be relevant to other Local Authority staff responsible for overseeing young people's use of the Internet (e.g. managers and staff in community education centers, residential homes for young people, libraries and other settings). These groups should take account of the messages about personal safety, and put into place the recommendations suitable for their setting.

Wednesday, May 07, 2008

BACK TO SCHOOL SAFETY ALERT:

CPSC Urges Bicyclists to Wear Helmets

CPSC Document #5002

Each year about 800 bicyclists are killed and more than half a million are treated in hospital emergency rooms. In recent years, almost two-thirds of the deaths and one-third of the injuries involved head and face injury. About one-half the injuries to children under the age of 10 involved the head or face. Helmets may reduce the risk of head injury to bicyclists by as much as 85 percent. Yet, only about 50 percent of bicyclists wear helmets.

The purpose of a helmet is to absorb the energy of an impact to minimize or prevent a head injury. Crushable, expanded polystyrene foam generally is used for this purpose.

A bicycle helmet should have a snug but comfortable fit on the rider's head. Some helmets are available with several different thicknesses of internal padding to custom fit the helmet to the user. If a parent is buying a helmet for a child, the CPSC recommends that the child accompany the parent so that the helmet can be tested for a good fit.

For a helmet to provide protection during impact, it must have a chin strap and buckle that will stay securely fastened. No combination of twisting or pulling should remove the helmet from the head or loosen the buckle on the strap. Children should be instructed to always wear the helmet level on the forehead, not tilted back. The chin strap should be adjusted correctly and firmly buckled.

Helmets manufactured after March 1999, are required by federal law to meet the CPSC standard. When purchasing a helmet, consumers are urged to examine the helmet and accompanying instructions and safety literature carefully. Consumers should also look for a label stating conformance with the CPSC standard.

Bicyclists should avoid riding at night. If you must ride at night, install and use front and rear lights on the bicycle and wear clothing with reflective tape or markings. These precautions are in addition to the reflectors that the CPSC requires to be on the front, rear, pedals, and wheels of bicycles.

Many bicycle-car crashes can be avoided by applying the rules of the road and by increasing attentiveness of cyclists and motorists. Bicyclists have a legal right to share the road, but they are often not noticed in traffic. Drivers should always keep an eye out for bicyclists, especially when turning, merging, changing lanes, or entering intersections.

Monday, April 28, 2008

All-Terrain Vehicle Safety

Too many ATV riders -- young and old -- are dying or experiencing life altering injuries from incidents involving ATVs. The U.S. Consumer Product Safety Commission (CPSC) recommends that all ATV riders follow the seven safety tips below every time they ride.

An estimated 740 people died in 2003* in incidents associated with ATVs. In addition, in 2004* there were an estimated 136,100 emergency room treated injuries associated with ATVs. About a third of all deaths and injuries involved victims under 16 years old. CPSC also reported that ridership has continued to grow, with 6.2 million 4-wheeled ATVs in use in 2003*.

The major ATV manufacturers agreed in Consent Decrees in 1988 and in subsequent voluntary action plans that they would not manufacture three-wheel ATVs; they would place engine size restrictions on ATVs sold for use by children under 16; and they would offer driver-training programs.

Children and young people under the age of 16 should not ride adult ATVs.

All ATV users should take a hands-on safety training course.

Always wear a helmet and safety gear such as boots and gloves while on an ATV.

Never drive an ATV on paved roads.

Never drive while under the influence of drugs or alcohol.

Never drive a youth or single-rider adult ATV with a passenger, and never ride these vehicles as a passenger.

There are some ATVs that are designed for two riders. Passengers on tandem ATVs should be at least 12 years old.

Monday, April 21, 2008

J-Hook Shaped Stake style (Anchor Types)

This style is used when holes are not pre-drilled into the ground shoes (bars) or rear ground shoe (bar) of the goal. Similar to the peg or stake style, this anchor is hammered, at an angle if possible, directly into the earth. The curved (top) portion of this anchor fits over the goal member to secure it to the ground. Typically, two to four stakes of this type are recommended (per goal), depending on stake structure, manufacturers specifications, weight of goal, and soil conditions. Stakes with larger diameters or textured surfaces have greater holding capacity.

Monday, April 14, 2008

Anchoring/Securing/Counterweighing Guidelines

A properly anchored/counterweighted movable soccer goal is much less likely to tip over. Remember to secure the goal to the ground (preferably at the rear of the goal), making sure the anchors are flush with the ground and clearly visible. It is IMPERATIVE that ALL movable soccer goals are always anchored properly (see Figure 2). There are several different ways to secure your soccer goal. The number and type of anchors to be used will depend on a number of factors, such as soil type, soil moisture content, and total goal weight.

Monday, April 07, 2008

Soccer Goal Injuries and Deaths

According to the 1994 National Soccer Participation Survey (Soccer Industry Council of America), over 16 million persons in the United States play soccer at least once a year. Seventy-four percent (over 12 million) of these persons are under the age of 18. Soccer ranks fourth in participation for those under 18, following basketball, volleyball, and softball and well ahead of baseball, which has an annual participation of 9.7 million.
There are approximately 225,000 to 500,000 soccer goals in the United States. Many of these soccer goals are unsafe because they are unstable and are either unanchored or not properly anchored or counter-balanced. These movable soccer goals pose an unnecessary risk of tip over to children who climb on goals (or nets) or hang from the crossbar.
The CPSC knows of four deaths in 1990 alone and at least 21 deaths during the past 16 years (1979-1994) associated with movable soccer goals. In addition, an estimated 120 injuries involving falling goals were treated each year in U.S. hospital emergency rooms during the period 1989 through 1993. Many of the serious incidents occurred when the soccer goals tipped over onto the victim. Almost all of the goals involved in these tip over appeared to be home-made by high school shop classes, custodial members, or local welders, not professionally manufactured. These home-made goals are often very heavy and unstable.
The majority of movable soccer goals are constructed of metal, typically weighing 150-500 pounds. The serious injuries and deaths are a result of blunt force trauma to the head, neck, chest, and limbs of the victims. In most cases this occurred when the goal tipped or was accidentally tipped onto the victim. In one case an 8-year-old child was fatally injured when the movable soccer goal he was climbing tipped over and struck him on the head. In another case, a 20-year-old male died from a massive head trauma when he pulled a goal down on himself while attempting to do chin-ups. In a third case, while attempting to tighten a net to its goal post, the victim’s father lifted the back base of the goal causing it to tip over striking his 3-year-old child on the head, causing a fatal injury.
High winds can also cause movable soccer goals to fall over. For example, a 9-year-old was fatally injured when a goal was tipped over by a gust of wind. In another incident, a 19-year-old goalie suffered stress fractures to both legs when the soccer goal was blown on top of her.

Sunday, March 30, 2008

B.C.-Canada Place officially closes doors

Monday, March 20, 2006 marks the official close of British Columbia-Canada Place, one of the most successful attractions of the 2006 Torino Olympic and Paralympic Winter Games.

Over the course of the 2006 Olympic and Paralympic Winter Games, British Columbia-Canada Place drew more than 100,000 visitors and journalists. These visitors were able to experience first hand the province’s culture, heritage, natural beauty and bustling cities. Also, more than 80 British Columbia businesses were able to connect with an international audience and showcase some of B.C.’s best products and services.

B.C.-Canada Place will be a legacy to the people of Torino. The official transfer took place in a ceremony yesterday, with Torino Mayor Sergio Chiamparino accepting a ceremonial key to the building.

“This generous gift from British Columbia will be a constant reminder of our friends in Canada and the celebrations that took place in our city during the 2006 Winter Games,” says Mayor Chiamparino. “We are honored to have this permanent B.C. presence in our city.”

Monday, March 24, 2008

Kent Kickin' Mini-Scooters

Kent is recalling about 90,000 scooters. The scooter handles can unexpectedly come out of the steering column if the clamp holding them in is not tight, causing the rider to lose control, fall and possibly suffer injuries.
Kent has received four reports of the handles coming out, resulting in four children suffering injuries, including broken arms, a broken wrist, bruises, abrasions and a cracked tooth.
These are Kickin' Mini-Scooters made of chrome-plated steel. A vertical decal on the steering column reads "KICKIN' MINI SCOOTER." The scooter's black plastic platform measures about 15 inches long, and it has 4-inch translucent in-line style wheels. "KENT" and "MADE IN CHINA" are written on the lower part of the steering column. The scooters were sold with black backpacks embroidered in white with the word "Kickin."
Toys R us stores nationwide sold the Kent scooters from May 2000 through September 2000 for about $60.
Consumers should stop riding these Kent scooters immediately, and call Kent International to receive a free replacement handlebar with pins to secure the handlebars. For more information, call Kent International at (800) 451-KENT (5368) between 8 a.m. and 5 p.m. ET Monday through Friday.
Kent has sold other models to Toys R Us such as the Street Craze, the Street Racer and Scoot that are NOT part of this recall. Scooters that Kent sold to Wal Mart, Meijer's, Target and AAFES are also NOT part of this recall.

Monday, March 17, 2008

Trampoline Safety Alert

The U. S. Consumer Product Safety Commission (CPSC) wants you and your family to be safe when using trampolines. The CPSC estimates that in 2001 there were 91,870 hospital emergency room-treated injuries associated with trampolines. About 93 percent of the victims were under 15 years of age, and 11 percent were under 5 years of age. Since 1990, CPSC has received reports of 6 deaths of children under age 15 involving trampolines. Injuries and deaths were caused by:

* Colliding with another person on the trampoline.
* Landing improperly while jumping or doing stunts on the trampoline.
* Falling or jumping off the trampoline.
* Falling on the trampoline springs or frame.
Most of the trampolines associated with injuries were at private homes.
Here are the steps you can take to help prevent serious trampoline injuries, especially paralysis, fractures, sprains, and bruises:

* Allow only one person on the trampoline at a time.
* Do not attempt or allow somersaults because landing on the head or neck can cause paralysis.
* Do not use the trampoline without shock-absorbing pads that completely cover its springs, hooks, and frame.
* Place the trampoline away from structures, trees, and other play areas.
* No child under 6 years of age should use a full-size trampoline. Do not use a ladder with the trampoline because it provides unsupervised access by small children.
* Always supervise children who use a trampoline.
* Trampoline enclosures can help prevent injuries from falls off trampolines.

Monday, March 10, 2008

Accumulator

In a computer CPU, an accumulator is a register in which intermediary arithmetic and logic results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation (addition, multiplication, shift, etc.) to main memory, possibly only to be read right back again for use in the next operation. Access to main memory is slower than access to a register like the accumulator because the technology used for the huge main memory is slower (but cheaper) than that used for a register.

The canonical example for accumulator use is adding a list of numbers. The accumulator is initially set to zero, then each number in spin is added to the value in the accumulator. Only when all numbers have been added is the result seized in the accumulator written to main memory or to another, non-accumulator, CPU register.

Monday, February 25, 2008

Silicon dioxide

The chemical compound silicon dioxide, also known as silica or silox (from the Latin "silex"), is the oxide of silicon, chemical formula SiO2, and has been known for its hardness since the 9th century. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms. It is a principal component of most types of glass and substances such as concrete.

Sunday, February 17, 2008

Viable Systems Model

The Viable Systems Model is a abstract model of the organisational structure of any viable or autonomous system. A viable system is any system organised in such a way as to meet the demands of surviving in the changing environment. One of the prime features of systems that survive is that they are adaptable. The VSM expresses a model for a viable system, which is an abstracted cybernetic description that is applicable to any organisation that is a viable system and capable of autonomy.