日历

« 2008-12-02  
 123456
78910111213
14151617181920
21222324252627
28293031   

我的栏目

RSS订阅

for the life road ..make a friend here...come on !~
  • Worlds within Worlds

    2007-08-07 14:15:11

     First of all let us consider the earth (that is to say, the world) as a planet revolving round the sun. The earth is one of mine planets which move in orbit round the sun. These nine planets, together with the sun, make up what is called our solar system. How this wonderful system started and what kept it working with such wonderful accuracy is largely a mystery but astronomers tell us that it is only one of millions of similar systems is space, and one of the smallest.
         The stars which we see glittering in the sky on a dark and cloudless night are almost certainly the suns of other solar systems more or less like our own, but they are so far away in space that it is unlikely that we shall ever get to know very much about them. About our own solar system, however, we are learning more every day.
         Before the American and Russian astronauts made their thrilling journeys into outer space it was difficult for us to realise what our earth looked like from hundreds of thousands of miles away, but the photographs which the astronauts were able to take show us the earth in space looking not very different from what the moon looks like when we look at it from the earth. The earth is, however, very different from the moon, which the American astronauts have found to be without life or vegetation, whereas our earth is very much alive in every respect. The moon, by the way , is called a satellite because it goes round our earth as well as round the sun. In other words, it goes round the sun with our earth.
         The surface of our earth is covered by masses of land and larger areas of water. Let us consider the water areas first. The total water area is about three times as large as the land area. The very large separate areas of water are called "oceans" and the lesser areas are called "seas."
         In most of the oceans and seas some of the water is found to be flowing in a particular direction - that is to say, from one part towards another part of the ocean or sea concerned. The water which is flowing in this manner is said to be moving as a "current." There are many thousands of currents in the waters of the oceans and seas, but only certain of the stronger and better marked currents are specially named and or great importance. These currents are important because they affect the climate of the land areas close to where they flow and also because they carry large quantities of microscopic animal and vegetable life which forms a large part of the food for fishes.
         The nature and characteristics of the surface of the land areas of the earth vary a great deal from area to area and from place to place. The surface of some areas consists largely of high mountains and deep valleys whilst, in other areas, most of the surface consists of plains. If one made a journey over the Continents one would find every kind of surface including mountain ranges, plains, plateaux, deserts, tropical forestlands and empty areas covered permanently by ice and snow.
         When thinking and learning about the world we should not forget that our world is the home of a very great many different people - peoples with different colored skins, living very different lives and having very different ideas about a great many important things such as religion, government, education and social behavīor.
         The circumstances under which different people live make a great difference between the way in which they live and the way in which we live, and it ought to be our business to try to understand those different circumstances so that we can better understand people of other lands. Above all, we should avoid deciding what we think about people different from ourselves without first having learned a great deal about them and the kind of lives they have to live. It is true to say that the more we learn about other people, the better we understand their ideas and, as a rule, the better we like those people themselves.
  • Why hearty women outlive men

    2007-07-25 10:25:45

    Why hearty women outlive men
    The age-old riddle of why many women live longer than men has been solved. It's their pumping power, British researchers have found.

    On average, women live five years longer than men and women over the age of 60 are now the fastest-growing section of the British population.

    The average male heart becomes weaker with age, and by the age of 70 its power to pump blood around the body could have decreased by up to a quarter of its youthful strength.

    David Goldspink, Professor of Cell and Molecular Sports Science at Liverpool John Moores University, said yesterday that women's longevity is linked to the strength of their hearts. Unlike men, they pump just as strongly at 70 as they do at 20.

    "We have found that the power of the male heart falls by 20-25 per cent between 18 and 70 years of age," Professor Goldspink said. "In stark contrast, over the same period there was no age-related decline in the power of the female heart, meaning that the heart of a healthy 70-year-old woman could perform almost as well as a 20-year-old's."

    The dramatic difference between the sexes might explain why women live longer. The good news is that men of any age can improve the health of their heart simply by taking more regular exercise.

    The results are based on the findings of a two-year study of a cross-section of the British population, which examined the effects of ageing on the cardiovascular system.

    Professor Goldspink and a team of scientists at the university's Research Unit for Human Development and Ageing examined more than 250 men and women between 18 and 80.

    None of the volunteers had a weekly exercise routine and all were considered to have low fitness levels, but were otherwise healthy. Each volunteer underwent five hours of tests to measure their blood pressure and the performance of their heart while at rest and while they exercised on a treadmill.

    The researchers found that the large arteries in the body became stiffer and less elastic with age, causing increased blood pressure. Blood flow to the muscles and skin of the limbs was also found progressively to decrease. These changes were found to occur earlier in men, but women caught up soon after the menopause.

Open Toolbar