Thursday, December 25, 2008

Written languages

In a sense, written language should be distinguished from natural language. Until recently in the developed world, it was common for many people to be fluent in spoken or signed languages and yet remain illiterate; this is still the case in poor countries today. Furthermore, natural language acquisition during childhood is largely spontaneous, while literacy must usually be intentionally acquired.

Monday, December 15, 2008

Benign tumor

A benign tumor is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor does not grow in an unlimited, aggressive manner, does not invade surrounding tissues, and does not metastasize. Common examples of benign tumors include moles and uterine fibroids.

The term "benign" implies a mild and nonprogressive disease, and indeed, many kinds of benign tumor are harmless to the health. However, some neoplasms which are defined as 'benign tumors' because they lack the invasive properties of a cancer, may still produce negative health effects. Examples of this include tumors which produce a "mass effect" (compression of vital organs such as blood vessels), or "functional" tumors of endocrine tissues, which may overproduce certain hormones (examples include thyroid adenomas, adrenocortical adenomas, and pituitary adenomas).

Benign tumors typically are encapsulated, which inhibits their ability to behave in a malignant manner. Nonetheless, many types of benign tumors have the potential to become malignant and some types, such as teratoma, are notorious for this.

Wednesday, December 03, 2008

Rice


Rice is a cereal foodstuff which forms an important part of the diet of many people worldwide and as such it is a staple food for many.

Domesticated rice comprises two species of food crops in the Oryza genus of the Poaceae ("true grass") family: Asian rice, Oryza sativa is native to tropical and subtropical southern Asia; African rice, Oryza glaberrima, is native to West Africa.

The name wild rice is usually used for species of the different but related genus Zizania, both wild and domesticated, although the term may be used for primitive or uncultivated varieties of Oryza.

Rice is grown as a monocarpic annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop and survive for up to 20 years.Rice can grow to 1–1.8 m tall, occasionally more depending on the variety and soil fertility. The grass has long, slender leaves 50–100 cm long and 2–2.5 cm broad. The small wind-pollinated flowers are produced in a branched arching to pendulous inflorescence 30–50 cm long. The edible seed is a grain (caryopsis) 5–12 mm long and 2–3 mm thick.

Rice is a staple food for a large part of the world's human population, especially in tropical Latin America, and East, South and Southeast Asia, making it the second-most consumed cereal grain. A traditional food plant in Africa, Rice has the potential to improve nutrition, boost food security, foster rural development and support sustainable landcare. Rice provides more than one fifth of the calories consumed worldwide by humans.In early 2008, some governments and retailers began rationing supplies of the grain due to fears of a global rice shortage.