Thursday, May 31, 2007

Genetics

Genetics is the science of heredity and variation in living organisms.Knowledge that desired characteristics were present at birth has been implicitly used since prehistoric times for improving crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the mechanisms of inheritance, only began with the work of Gregor Mendel in the mid-1800s.

Mendel observed that inheritance is basically a discrete process with specific traits that are inherited in an independant manner. These basic units of inheritance is now known as "genes". In the cells of organisms, genes exist actually in the structure of the molecule DNA and the information genes contain is used to create and control the components of cells. Although genetics plays a large role in determining the appearance and behavior of organisms, it is the interaction of genetics with the environment an organism experiences that determines the ultimate outcome. For example, while genes play a role in determining a person's height, the nutrition and health that person experiences in childhood also have a large effect.

Sunday, May 27, 2007

Mental health

Mental health is a idea that refers to a human individual's emotional and psychological well-being. Merriam-Webster defines mental health as "A state of emotional and psychological well-being in which an individual is able to use his or her cognitive and emotional capabilities, function in society, and meet the ordinary demands of everyday life."

According to the World Health Organization (WHO), there is no one "official" definition of mental health. Cultural differences, subjective assessments, and competing professional theories all affect how "mental health" is defined. In general, most experts agree that "mental health" and "mental illness" are not opposites. In other words, the absence of a recognized mental disorder is not of necessity an indicator of mental health.
One way to think about mental health is by looking at how efficiently and successfully a person functions. Feeling capable and competent; being able to handle normal levels of stress, preserve satisfying relationships, and lead an independent life; and being able to "bounce back," or recover from difficult situations, are all signs of mental health.
Encompassing your emotional, social, and—most importantly—your mental well-being; All these aspects—emotional, physical, and social—must function jointly to achieve overall health.

Monday, May 21, 2007

Snake River

The Snake River is a river in the western part of the United States. The Snake River is 1,038 miles in length, and is the Columbia River's main branch. The Lewis and Clark expedition was the first major U.S. investigation of the river, and the Snake was once known as the Lewis River.

The Snake originates near the Continental Divide in Yellowstone National Park in NW Wyoming and flows south to Jackson Lake in Grand Teton National Park and long-ago the town of Jackson. The river flows down Snake River Canyon, then enters Idaho at the Palisades Reservoir and joins with the Henrys Fork River near Rigby. Note: inhabitants of eastern Idaho generally call the Snake prior to this joining the "South Fork of the Snake", individual it from the Henrys Fork.

Tributaries of the Snake contain the Henrys Fork River, the Boise River, the Salmon River, and the Clearwater River.

The Snake River's lots of hydroelectric power plants are a major source of electricity in the region. Its watershed provides irrigation for various projects, including the Minidoka, Boise, Palisades, and Owyhee projects by the U.S. Bureau of Reclamation, as well as a diversity of private projects such as at Twin Falls. However, these dams have also had an adverse environmental effect on wildlife, most notably on wild salmon migrations.

The Snake runs through a number of gorges, including one of the deepest in the world, Hells Canyon, with a greatest depth of 7,900 feet.

The name "Snake" possibly derived from an S-shaped sign which the Shoshone Indians made with their hands to mimic swimming salmon variation names of the river have included:

Wednesday, May 16, 2007

Refrigerator

A typical refrigerator with its door open refrigerator is a cooling machine comprising a thermally insulated compartment and a mechanism to transfer heat from it to the outside environment, cooling the contents to a temperature below ambient. Refrigerators are widely used to store foods which deteriorate at ambient temperatures; spoilage due to bacterial growth and other processes is much slower at low temperatures. Devices described as "refrigerators" maintain a temperature a few degrees above the freezing point of water; similar devices which maintain temperatures below the freezing point of water are called "freezers". The refrigerator is a relatively modern creation amongst kitchen appliances. It replaced the common icebox which had been a household item for almost a century and a half prior, and is sometimes still called by the original name "icebox".

Sunday, May 13, 2007

Ancient Tamil gods and goddesses

The religion of the ancient Tamils directly followed Hinduism.although persisting with its roots of nature worship. The most popular deity was Murugan, who has from a very early date been recognized with Karthikeya, the son of Siva. Muruga might have been a different deity at first stemming from a local deity. According to the noted expert on Tamil culture Kamil V. Zvelebil, "Subrahmanya-Murugan is one of the most complicated and baffling deities for analysis". The worship of Amman or Mariamman, consideration to have been derived from Kotravai, an ancient mother goddess, also was very common. Kannagi, the heroine of the Cilappatikaram, was worshipped as Pathini by many Tamils, particularly in Sri Lanka. There were also many temples and devotees of Thirumaal, Siva, Ganapathi, and the other common Hindu deities.

Tuesday, May 08, 2007

Key

A key is a device which is used to open a lock. It typically consists of a specially-shaped piece of flat metal, with cut notches (forming teeth), and/or milled grooves which fit the shape of the lock and can open the properly combinated lock by (usually) being turned in the lock housing. This portion of the key is referred to as the blade. The wider grip, referred to as the bow, is establish at the top of the key to facilitate turning. regularly, there are only a small number of keys which can work a certain lock. In some residential locks, all of the keys for a lock are given to the purchaser of the lock. Duplicates of the key can usually be made by anyone with the correct key blank and key machine. Some manufacturers assign an identification number to each lock and key combination. Knowing the identification number of such a lock allows a duplicate key to be made at certain places. Many residential keys are recognized by the key cuts stamped on the key bow.
Most people in modern society use keys on a daily basis, to secure their home, their vehicle, or to access their workplace, among other uses. Those that use a number of keys will typically place them on a ring or key chain, often with other items such as key fobs.

Friday, May 04, 2007

Lightning

Lightning is an influential natural electrostatic release produced during a thunderstorm. Lightning's abrupt electric release is accompanied by the emission of visible light and other forms of electromagnetic radiation. The electric current passing through the release channels quickly heats and expands the air into plasma, producing acoustic shock waves in the atmosphere.

Early lightning investigate
During early investigations into electricity via Leyden jars and other instruments, a number of people planned that small scale sparks shared some similarity with lightning.
Benjamin Franklin, who also imaginary the lightning rod, endeavored to test this theory by using a spire which was being erected in Philadelphia. Whilst he was waiting for the spire completion some others conducted at Marly in France, what became to be known as the Philadelphia experiments that Franklin had optional in his book?
Franklin typically gets the credit for being the first to perform this research. The Franklin myth goes like this:
Whilst coming up for completion of the spire, he got the idea of using a flying object, such as a kite in its place. During the next shower, in June 1752, he raised a kite, accompanied by his son as an assistant. On his end of the string he emotionally involved a key and tied it to a post with a silk thread. As time passed Franklin noticed the loose fibers on the string stretching out; he then brought his hand close enough to the key and a flash jumped the gap. The rain which had fallen during the storm had covered with water the line and made it conductive.
However, in his memoirs, Franklin obviously states that he only performed this research after those made in France.
As news of the research and its specifics spread, it was met with attempts at duplication. Experiments involving lightning are always risky and commonly fatal. The most well known death during the rash of Franklin-imitators was Professor George Richman, of Saint Petersburg, Russia. He had shaped a setup similar to Franklin's, and was attending a meeting of the Academy of Sciences, when he heard thunder. He ran home with his engraver to capture the event for posterity. While the research was underway, a large ball lightning showed up, collided with Richman's head, and killed him, leaving a red spot. His shoes were blown open, parts of his clothes singed, the engraver knocked out, the doorframe of the room was split, and the door itself ragged off its hinges.