Tuesday, June 29, 2010
WHAT IS ALLERGY??
Allergy is an overreaction of the body's natural immune system towards substances that are otherwise harmless.
The human body has its own independent defence mechanism- the immune system- to protect itself against potentially harmful substances. A healthy immune system only reacts when it identifies harmful or foreign substances, such as bacteria or other microbes. Sometimes, the immune system mistakenly identifies substances that are usually harmless, such as pollen, dust, mould or certain foods, to be harmful and then triggers a series of reactions, leading to various systoms of allergy.
WHAT CAUSES AN ALLERGY??
While many allergic triggers come from the environment, the likelihood of allergic response is often genetically determined. Family history is the most important factor, children from allergic particularly if the parents and siblings have experienced some forms of allergy, such as food allergy, asthma, atopic eczema and hay fever.
Posted by switsmile at 10:22 PM
Although it creeps over the sky every 24hours, the night is still a special time for the most people. Its darkness can produce contradictory feelings, it can bring peace and relief from the daily stresses, but it can also cause anxiety and fear. The darkness swallows colours, blurs shapes and makes familiar things appear strange. But why is the night so black??
Although it dominates our solar system, the sun is just one star among billions in the universe. Of course, it is special for us when it sets in the evening, the light goes out.
This is very familiar process for us, but why shouldn't the other stars take the sun's place after sunset, providing us with light until sunrise?? Of coz this is impossible. The stars in the sky only light up like tiny pinpoints, and cannot banish the darkness. Sometimes the brightness of city lights even prevents us from seeing the stars.
During the day, the sun overpowered the other stars, so their little light could only be seen at night. Since the dawn of human society, we have been fascinated by the way the brightness of the day alternates with the darkness of the night.
Posted by switsmile at 8:32 PM
Saturday, June 19, 2010
The most mysterious object in the universe must certainly be the invisible and inconceivably dense objects known as black holes.
Nothing can escape the grip of a black hole.
To imagine a black hole,think of an abyss-small in size and yet unimaginably dense-that swallows everything that comes within its reach. The formal defination of BLACK HOLE is a star that has collapsed under its own weightseveral times,becoming more compact each time.Because of its extreamly high density, this bottomless pit attracts even the smallest speck of dust that comes near. Nothing, absolutely nothing, can escape the pull of black hole- not even light. In fact, this is why it is known as a BLACK HOLE.
Posted by switsmile at 5:17 PM