Thursday, December 28, 2006

Perception of sound

Sound is perceived through the sense of hearing. Humans and many animals use their ears to hear sound, but loud sounds and low frequency sounds can be supposed by other parts of the body through the sense of touch. Sounds are used in several ways, most notably for announcement through speech or, for example, music. Sound can also be used to acquire information about properties of the neighboring environment such as spatial characteristics and presence of other animals or objects. For example, bats use echolocation, ships and submarines use sonar, and humans can determine spatial information by the way in which they perceive sounds.

The range of frequencies that humans can hear well is between about 20 Hz and 16,000 Hz. This is by description the hearing range, but most people can hear above 16,000 Hz provided the sound pressure level is above the hearing threshold level. At 40,000 Hz and higher frequencies, for instance, this level is about 140 dB. The audible range varies by individual and, mostly in the upper part of the range, hearing damage accumulates with age. The ear is most sensitive to frequencies around 3,500 Hz. Sound above the hearing range is known as ultrasound and that below the hearing range as infrasound.

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Thursday, December 21, 2006


Hinduism Dharma also known as Vaidika is a religion or philosophy that originated from the Indian subcontinent and nearby close areas. The term Hinduism is heterogeneous, as Hinduism consists of several schools of thought. It encompasses many religious rituals that widely vary in practice, as well as many diverse sects and philosophies. Many Hindus, influenced by Advaita philosophy, venerate an array of deities, considering them manifestations of the one supreme monistic Cosmic Spirit, Brahman, while many others focus on a singular concept of Brahman, as in Vaishnavism, Saivism and Shaktism.

Hinduism is the third major religion in the world, with approximately 900 million adherents, of whom approximately 890 million live in India. It is also the oldest known religion in the world today. Unlike many other religions, Hinduism has no main founder. It also has no single holy book — it has many, with all pointing to the same Truth - its original scriptures were the four Vedas, but as time has passed, many other scriptures have also emerged.

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Sunday, December 17, 2006

Cellular differentiation

Cellular differentiation is a concept from developmental biology describing the process by which cells acquire a "type". The morphology of a cell may change considerably during differentiation, but the genetic material remains the same, with few exceptions.

A cell that is able to differentiate into many cell types is known as pluripotent. These cells are called stem cells in animals and meristematic cells in higher plants. A cell that is able to distinguish into all cell types is known as totipotent. In mammals, only the zygote and early embryonic cells are totipotent, while in plants, many differentiated cells can become totipotent with simple laboratory techniques.

In most multicellular organisms, not all cells are alike. For example, cells that make up the human skin are different from cells that make up the inner organs. Yet, all of the different cell types in the human body are all derived from a single fertilized egg cell through differentiation.

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Sunday, December 10, 2006

Etymology of India

India, as a country and nation, has three principal names, in both official and popular usage, each of which is historically and culturally important. All three originally designated a single entity comprise all the modern nations of the Indian subcontinent. The first Article of the Constitution of India, which deals with the official name, states that "India, that is Bharat, shall be a union of states." Thus, not only in usage but officially India and Bharat are both accorded primary status? The name India is derived from the river Indus.

The innovative name of the river came from the fact that in the north-west of the subcontinent, there are seven main tributaries of the one river. The local inhabitants therefore called it Sapta-Sindhu, meaning the seven rivers. As the seven tributaries are part of the one river, the whole river system came to be known in time as Sindhu. In general, Sindhu also means any river or water body in Sanskrit.

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Thursday, December 07, 2006

Competition in education

Competition is also very obvious in education. On a global scale, national education systems, intending to bring out the best in the next generation, encourage competitiveness amongst students by scholarships. Countries like Singapore and the England have a gifted education programmed which caters to gifted students, prompting charge of academic elitism. Upon receipt of their academic results, students tend to compare their grades to see who is better. For severe cases, the pressure to perform in some countries is so high that it results in stigmatization of intellectually lacking students or even suicide as consequence of failing the exams, Japan being a prime example.
This resulted in critical revaluation of examinations as a whole by educationists . Critics of competition as opposed to excellence as a motivating factor in education systems, such as Alfie Kohn, assert that competition actually has a net negative influence on the achievement levels of students and that it "turns all of us into losers." Competitions also make up a large promoter of extracurricular activities that students partake in. Such competitions include TVO's broadcast Reach for the Top competition, FIRST Robotics and the University of Toronto Space Design Contest.

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