Dangers Await Babies with Altitude

　　Women who live in the world’s highest communities tend to give birth to underweight babies, a new study suggests. These babies may grow into adults with a high risk of heart disease and strokes.1

　　Research has hinted that newborns in mountain communities are lighter than average. But it wasn’t clear whether this is due to reduced oxygen levels at high altitudes or because their mothers are under-nourished — many people who live at high altitudes are relatively poor compared with those living lower down.

　　To find out more, Dino Giussani and his team at Cambridge University studied the records of 400 births in Bolivia during 1997 and 1998. The babies were bom in both rich and poor areas of two cities: La Paz and Santa Cruz. La Paz is the highest city in the world, at 3.65 kilometers above sea level, while Santa Cruz is much lower, at 0.44 kilometers.

　　Sure enough, Giussani found that the average birthweight of babies in La Paz was significantly lower than in Santa Cruz. This was true in both high and low-income families. Even babies bom to poor families in Santa Cruz were heavier on average than babies born to wealthy families in lofty La Paz. “We were very surprised by this result,” says Giussani.

　　The results suggest that babies bom at high altitudes are deprived of2 oxygen before birth. “This may trigger the release or suppression of hormones that regulate growth of the unborn child,3 ”says Giussani.

　　His team also found that high-altitude babies tended to have relatively larger heads compared with their bodies4. This is probably because a fetus starved of oxygen will send oxygenated blood to the brain in preference to the rest of the body.5

　　Giussani wants to find out if such babies have a higher risk of disease in later life. People born in La Paz might be prone to heart trouble in adulthood, for example. Low birthweight is a risk factor for coronary heart disease. And newborns with a high ratio of head size to body weight are often predisposed to high blood pressure and strokes in later life.

　　练习：

　　1.According to the passage, one of the reasons why newborns in mountain communities are underweight is that their mothers are under-nourished.

　　A　Right　B　Wrong　C　Not mentioned

　　2.Giussani’s team members are all British researchers and professors from Cambridge University.

　　A　Right　B　Wrong　C　Not mentioned

　　3.Giussani did not expect to find that the weight of a baby had little to do with the financial conditions of the family he was bom into.

　　A　Right　B　Wrong　C　Not mentioned

　　4.The weight of a newborn has to do with the supply of oxygen even when he was still in his mother’s womb.

　　A　Right　B　Wrong　C　Not mentioned

　　5.High-altitude babies have heads that are larger than their bodies.

　　A　Right　B　Wrong　C　Not mentioned

　　6.High-altitude babies have longer but thinner limbs than average.

　　A　Right　B　Wrong　C　Not mentioned

　　7.Giussani has arrived at the conclusion that babies in high-altitude regions are more likely to have heart trouble when they grow up.

　　A　Right　B　Wrong　C　Not mentioned

　　答案与题解：

　　1.B　本题的依据是第二段中的一句话：But it wasn’t clear whether ... or because their mothers are under-nourished ...可见，婴儿体重不足是否因为母体营养不足尚不能肯定。

　　2.C　第三段中提到Giussani在剑桥大学有一个研究组，但其中的成员是什么人却没有讲到。

　　3.A　第四段里说Giussani发现在La Paz出生的婴儿比在Santa Cruz出生的婴儿明显要轻，不论是高收入的家庭还是低收入的家庭都是这样，最后的一句话是：We were very surprised by this result，说明这个结果是他所没有料到的。

　　4.A　第五段的第一句话是... babies bom at high altitudes are deprived of oxygen before birth。也就是说孩子还在母亲的子宫内时就已经缺氧了，这种缺氧的状又影响荷尔蒙的释放或抑制，这些荷尔蒙又调节着婴儿的发育。

　　5.B　回答此题只需正确理解第六段中的... have relatively larger heads compared with their bodies。这并不是头比身体大，而是相对身体来说头显得较大。

　　6.C　关于婴儿四肢的大小文中完全没有提及。

　　7.B　这不是Giussani已得出的结论，而是他想找到答案的问题，请见最后一段的第一、二句：Giussani wants to find out ... for example。

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（责任编辑：何莹莹）