Out of 100's or perhaps 1000's only a dogen or so are true "megaportals" thats try tp represent the entire range of library knoweldge and practice..libaray portal should be comprehensive in covering their subject .
Wednesday, April 6, 2011
Thursday, March 31, 2011
BIOLOGY
Must Reads
The Hypothalamus
Wednesday March 30, 2011
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About the size of a pearl, the hypothalamus directs a multitude of important functions in the body. Connections with structures of the endocrine and nervous systems enable the hypothalamus to play a vital role in maintaining homeostasis. Homeostasis is the process of maintaining bodily equilibrium by monitoring and adjusting physiological processes. Some of the physiological processes regulated by the hypothalamus include blood pressure, body temperature, cardiovascular system functions, fluid balance, and electrolyte balance.
Directionally, the hypothalamus is just below or inferior to the thalamus. It is posterior to the optic chiasm and bordered on the sides by the temporal lobes and optic tracts. The location of the hypothalamus, specifically its close proximity to and interactions with the thalamus and pituitary gland, enables it to act as a bridge between the nervous and endocrine systems. In fact, the hypothalamus serves as a control center for many autonomic functions of the peripheral nervous system.
Learn more about the brain, see:
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Asexual Reproduction Pros and Cons
Friday March 25, 2011
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© J. Houseman; BIODIDAC | |
In asexual reproduction, one individual produces offspring that are genetically identical to itself. These offspring are produced by mitosis. There are many invertebrates, including sea stars and sea anemones for example, that reproduce by asexual reproduction. Common forms of asexual reproduction include budding, fragmentation, regeneration and parthenogenesis.
Asexual reproduction can be very advantageous to certain animals. Animals that remain in one particular place and are unable to look for mates would need to reproduce asexually. Another advantage of asexual reproduction is that numerous offspring can be produced without "costing" the parent a great amount of energy or time. A disadvantage of this type of reproduction is the lack of genetic variation. All of the organisms are genetically identical and therefore share the same weaknesses.
More Reproduction Information:
Bee Study Reveals Clues to the Aging Process
Thursday March 24, 2011
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Studies with bees reveal a possible link between brain proteins and dementia in humans. According to researcher Gro Amdam, brain cells in bees and in humans are similar. The studies revealed that when older bees assumed roles normally done by younger bees, some of the older bees had an increase in proteins that help to repair and maintain brain cells. The presence of the proteins coincided with their increased ability to learn and process information. These same proteins are also found in humans.
Amdam states, "This is evidence of a certain flexibility in the bee brain, and it is conceivable that the brains of other animals and humans could have a similar potential. If so, the question is whether we would be able to figure out how to tap into this flexibility." The older bees that had an increase in brain cell rebuilding proteins showed improvements in learning and memory ability. The other older bees that did not have an increase in the proteins continued to exhibit declines in short-term memory and learning ability. These symptoms are similar to those seen in people with dementia.
Learn more about this study:
- Bees Could Reveal Key to Dementia Science Daily
Heavier People Have Larger Leg Bones
Wednesday March 23, 2011
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Researchers from North Carolina State University have discovered that heavier individuals have femurs with a wider shaft. This discovery is good news for forensic scientists in that it could help them determine the identity of an unknown person from their remains. While the information gained from the study cannot pin-point a person's weight, it can help determine whether or not a person was overweight.
According to researcher Dr. Ann Ross, "This research allows us to determine whether an individual was overweight based solely on the characteristics of a skeleton's femur or thigh bone." The researchers suspect that the femurs of overweight individuals are larger due to the fact that they carry more weight. Heavier people also have a different gait to compensate for the excess weight, which could impact femur size.
Learn more about this study, see:
- Overweight People Really Are Big-Boned (Science Daily)
Heterozygous Traits
Saturday March 19, 2011
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An organism that is heterozygous for a trait has two different alleles for that trait. An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring. The process by which alleles are transmitted was discovered by Gregor Mendel and formulated in what is known as Mendel's law of segregation.
Mendel studied various characteristics of pea plants, one of which was seed color. The gene for seed color in pea plants exists in two forms. There is one form or allele for yellow seed color (Y) and another for green seed color (y). One allele is dominant and the other is recessive. In this example, the allele for yellow seed color is dominant and the allele for green seed color is recessive. Since organisms have two alleles for each trait, when the alleles of a pair are heterozygous (Yy), the dominant allele trait is expressed and the recessive allele trait is masked. Seeds with the genetic makeup of (YY) or (Yy) are yellow, while seeds that are (yy) are green.
More Genetics Information:
Seeing By Sound
Thursday March 17, 2011
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Researchers have discovered that some people who are born blind utilize the part of their brain that would normally process vision to process sound. The part of the brain that is responsible for processing visual and spacial information is called the visual cortex and is located in the occipital lobes of the cerebral cortex. Using MRI scanning, the researchers were able to analyze brain activity in 11 sighted individuals and 11 individuals who were blind from birth while they listened to tones. It was discovered that some areas of the visual cortex do not require visual data to process spatial information.
According to researcher Dr. Olivier Collignon, "The brain designates a specific set of areas for spatial processing, even if it is deprived of its natural inputs since birth. The visually deprived brain is sufficiently flexible that it uses "neuronal niche" to develop and perform functions that are sufficiently close to the ones required by the remaining senses. Such a research demonstrates that the brain should be more considered as a function-oriented machine rather than a pure sensory machine." The researchers contend that the results of this study indicate the brain's ability to adapt as a result of an ordeal.
Learn more about this study, see:
- Some Blind People 'See' With Their Ears (Science Daily)
Scent of Death Lures Flies
Wednesday March 16, 2011
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Credit: Dennis Hansen | |
Did you know that some plants trick insects into pollinating them? The orchid Satyrium pumilum does so in a very unusual fashion. It mimics the scent of rotting flesh in order to attract a particular type of fly known as a flesh-fly. These flies are attracted to carrion. They deposit their larvae on the dead flesh to grow and develop. The Satyrium pumilum orchids analyzed in the study are found across the Cape floral kingdom of South Africa.
According to lead researcher Timotheus van der Niet, "The flowers of the orchids are incredibly specialized. Not only do they have to entice flies in, but they have to get flies of the right size into the right position to pick up the pollen. We've found that scent plays a hugely important role in pulling in the flies, and even inside the flower different scents attract the flies into the right location to pick up the pollen. The combination of smell and sight is irresistible to some flies. The level of carrion mimicry is amazing; we even saw a female fly leave larvae in a flower because it thought it was carrion." The researchers state that this particular type of mimicry is highly developed and at a level previously unknown in plants.
Learn more about this study, see:
- Orchid Lures Flies With Scent of Rotting Flesh (Science Daily)
Plant Cell Mitosis Images
Saturday March 12, 2011
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© The Entangled Bank | |
Cell division is a process that enables organisms to grow and reproduce. Dividing cells go through an ordered series of events called the cell cycle. Mitosis is a phase of the cell cycle in which the genetic material from a parent cell is divided equally between two cells.
Before a dividing cell enters mitosis, it must duplicate its genetic material and increase its organelles and cytoplasm. This period of growth is called interphase.
Stages of Mitosis:
- Prophase
- Metaphase
- Anaphase
- Telophase
View all of the stages of mitosis as they occur in a plant cell at the Mitosis Image Gallery page. For additional information, be sure to visit the Mitosis Animation page.
All About Flowering Plants
Thursday March 10, 2011
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Flowering plants, also called angiosperms, are the most numerous of all the divisions in the Plant Kingdom. They are vital to all life on earth as they provide oxygen, shelter, clothing, food, and medicine for other living organisms. With the exception of extreme habitats, angiosperms populate every land biome and aquatic community.
Angiosperms are characterized by two basic systems: a root system and a shoot system. The flower, a component of the shoot system, is responsible for seed development and reproduction. Flowers that contain both male and female reproductive structures (stamens and carpels) are called perfect flowers. Flowers that are missing either stamens or carpels are called imperfect flowers. A complete flower contains not only stamens and carpels, but sepals and petals as well.
More Plant Information:
Can Eating Apples Help You Live Longer?
Wednesday March 9, 2011
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Apples contain high levels of naturally occurring antioxidants that protect the body against cell damaging free radicals. Researchers have now discovered that apple antioxidants called polyphenols can extend the average lifespan of fruit flies and other test animals. The study also showed that polyphenols help to improve mobility in fruit flies, as well as reduce the levels of chemical substances associated with aging.
In addition, apple antioxidant consumption has been shown to have beneficial results in humans. In studies, women who ate apples had a decreased risk of developing heart disease. Antioxidants are found in foods such as nuts and colorful fruits and vegetables. They have been shown to help reduce wrinkles, fight cancer, and even improve me.
Wednesday, March 30, 2011
DATA BASED MANAGEMENT SYSTEM
As one of the oldest components associated with computers, the database management system, or DBMS, is a computer software program that is designed as the means of managing all databases that are currently installed on a system hard drive or network. Different types of database management systems exist, with some of them designed for the oversight and proper control of databases that are configured for specific purposes. Here are some examples of the various incarnations of DBMS technology that are currently in use, and some of the basic elements that are part of DBMS software applications. As the tool that is employed in the broad practice of managing databases, the DBMS is marketed in many forms. Some of the more popular examples of DBMS solutions include Microsoft Access, FileMaker, DB2, and Oracle. All these products provide for the creation of a series of rights or privileges that can be associated with a specific user. This means that it is possible to designate one or more database administrators who may control each function, as well as provide other users with various levels of administration rights. This flexibility makes the task of using DBMS methods to oversee a system something that can be centrally controlled, or allocated to several different people. |
Tuesday, March 29, 2011
computer sciences
From Wikipedia, the free encyclopedia
HTML, which stands for HyperText Markup Language, is the predominant markup language for web pages. HTML is the basic building-blocks of webpages.
HTML is written in the form of HTML elements consisting of tags, enclosed in angle brackets (like <html>), within the web page content. HTML tags normally come in pairs like <h1> and </h1>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags).
The purpose of a web browser is to read HTML documents and compose them into visual or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.
HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts in languages such as JavaScript which affect the behavior of HTML webpages.
Web browsers can also refer to Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicitly presentational HTML markup.[1]
For the use of HTML on Wikipedia, see Help:HTML in wikitext.
| Filename extension | .html, .htm |
|---|---|
| Internet media type | text/html |
| Type code | TEXT |
| Uniform Type Identifier | public.html |
| Developed by | World Wide Web Consortium & WHATWG |
| Type of format | Markup language |
| Extended from | SGML |
| Extended to | XHTML |
| Standard(s) | ISO/IEC 15445 W3C HTML 4.01 W3C HTML5 (draft) |
HTML, which stands for HyperText Markup Language, is the predominant markup language for web pages. HTML is the basic building-blocks of webpages.
HTML is written in the form of HTML elements consisting of tags, enclosed in angle brackets (like <html>), within the web page content. HTML tags normally come in pairs like <h1> and </h1>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags).
The purpose of a web browser is to read HTML documents and compose them into visual or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.
HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts in languages such as JavaScript which affect the behavior of HTML webpages.
Web browsers can also refer to Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicitly presentational HTML markup.[1]
Monday, March 28, 2011
Friday, March 25, 2011
HISTORY OF Dr.S.R.RANGANATHAN
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Tuesday, January 4, 2011
INFORMATION SYSTEM
The term information system is derived from two words ie information and system.data becomes information when establish a relationship among different pieces of data or in in other words organised interpreted and proceesd data in logical form is information. "Structured data is information"
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