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石城县治疗附件炎多少钱石城处女膜修复手术哪家医院好的江西赣州妇幼保健院医生名单 For those of us who live in the northern part of the ed States, perhaps no other season transforms the environment quite as much as winter.对于那些生活在美国北部的人来说,也许与其它季节相比,冬季的环境变化更大。Snow makes the world over so that its hardly recognizable.白雪使整个世界焕然一新,所以很难分辨事物。 The scenery isnt the only thing that changes during the winter season, though.然而,在冬季风景并不是唯一的变化。Todays Moment of Science is about how winter transforms the way the environment sounds.今日时差N小时为你讲述:在冬季,怎么去听声音的季节变化。Before that first snowfall, when the ground has hardened from the cold temperatures, sound experiences its first winter makeover.第一场雪前,因气温下降地面变硬,这时声音开始第一次季节性变化。Just as smooth, hard surfaces like glass reflect light, the smoother and harder a surface, the better it reflects sound.就如同玻璃反射光线一般,地面越光滑,越坚硬,反射的音效就越好。The harder ground of the early winter season absorbs less sound. Thus, acoustic waves retain more of their energy when they reflect off the ground.早冬时节地面越坚硬,被地面吸收的声音越少。因此声波在地表进行反射时,会保留更多的能量。As a result, early winter sounds are louder and clearer. Pay attention, and you might notice that everything sounds a little bit crisper.结果你会发现,早冬季节的声音听起来更响更清楚。如果注意听,你会发觉万物听起来都带点清脆。After the first snow, sound is made over again. The porousness of snow makes it absorb sound.第一场雪后,声音又发生了新的变化。积雪融化深入土壤,使地面吸收声音。Specifically, snow tends to absorb higher frequency acoustical waves.具体来说,积雪倾向于吸收震动率高的声波。As a result, sound becomes quieter and somewhat distorted.因此,听到的声音音量变低,并有所歪曲。Without looking out your window, you might know it snowed simply from noticing how bird calls or passing cars are slightly muffled.即使不看窗外,你也能通过倾听略微压低的鸟叫声和汽车开过的声音判断下雪了。If the snow lingers or it is topped with rain, winter sound will be made over once more. As snow hardens, it becomes smoother, less porous.如果持续下雪或者出现雨夹雪天气,声音会再次改变。雪会结成冰,因此会变得光滑,渗透性弱。As you can probably guess, this means that the snow will, like the hardened ground that preceded it, reflect sound well.可以猜到,这就意味着结冰的雪会像其覆盖的僵硬的地面一样,很好地反射声波。Sound will once again be crisp and clear.声音又会变得清晰明了。This winter, see if you can hear how the season transforms sound, as well as the scenery. 这个冬季在欣赏景色变换的同时,去听听季节是怎样改变声音的吧。201205/181947赣州南康人民医院有做阴道松弛

赣州市赣南片区人民医院看不孕不育怎么样Biologists who study natures food chain agree about the basic links in the chain: sunlight provides fuel for plants, plants are consumed by herbivores, and herbivores are eaten by carnivores. But researchers arent sure about all the factors that control the chain.研究自然食物链的生物学家一致认为食物链有一个基本的关联:阳光为植物提供养料,植物被食草动物吃,食草动物被食肉动物吃。但研究人员并不确定控制食物链的所有因素。Traditionally, they have thought that food-chain populations are regulated from the bottom up. According to this idea, the availability of plants as food determines the size of animal populations in an area. But a study of a food chain in Isle Royal National Park, an island in Lake Superior, has shown that food-chain control can work in both directions.习惯上,他们认为食物链上的种群数量受到自下而上的控制。根据这种观念,可食用植物的面积决定了这个区域动物种群的大小。但位于苏必利尔湖上一个小岛上的皇家公园对食物链进行了一项研究,结果显示食物链的控制是双向的。In the islands food chain, balsam firs are eaten by moose, which, in turn, are eaten by wolves. When researchers tracked the effects of the moose and wolves on the balsam firs, they actually found that the number of wolves in the area affected the growth of the firs. During the study, researchers recorded the width of the tree rings of balsam firs. Each ring marked a year of the trees growth.在这个岛上的食物链中,香脂冷杉被驼鹿吃,反过来,驼鹿又被狼吃。当研究人员追踪驼鹿和狼对香脂冷杉的影响时发现,这片区域狼的数量实际上也会影响冷杉的生长。在研究过程中,研究人员记录了冷杉的年轮的宽度。每个年轮代表冷杉树一年生长了多少。A narrow ring indicated that the trees growth had been suppressed that year. The narrow rings appeared only after wolf populations decreased, allowing a greater number of moose to survive and eat more balsam firs. The researchers concluded that wolves play an important role in maintaining the complex and delicate balance of the islands food chain. This food chain appears to be regulated from the top as well as from the bottom.狭窄的年轮表示那一年树的生长受到抑制。但狭窄的年轮只出现在狼的数量减少之后。狼群数量减少使更多的驼鹿存活下来,它们会吃掉更多的冷杉树叶。研究人员总结到,狼群在保持这个岛上食物链的复杂性和微妙的生态平衡上扮演着重要的角色。因此食物链即受到来自底部的控制,也受到来自顶部的控制。原文译文属!201212/215356章贡人民医院有没有微信咨询 赣州石城医院哪年成立

会昌医院靠谱吗Books and Arts;文艺;Britains third-world economy英国的第三世界经济Relegation for Albion大不列颠的陨落Going South: Why Britain Will Have A Third World Economy By 2014. By Larry Elliott and Dan Atkinson.《滑向全球之南:为什么2014年的英国会有一个第三世界经济》;作者Larry Elliott,Dan Atkinson。Palgrave Macmillan; The journalistic team of Larry Elliott and Dan Atkinson proved to be more perceptive than most of their peers in skewering Britains debt-fuelled boom. Their two previous books, “Fantasy Island” (2007) and “The Gods That Failed” (2008), analysed why it happened and who was to blame. So they will have a y audience for their latest tale of woe, which forecasts the imminent loss of Britains developed-economy status.事实明,Larry Elliott和Dan Atkinson的记者团队在描绘被债务吹高的英国繁荣方面比他们的大多数同僚更具慧眼。他们之前的两部作品《幻想岛》和《失灵的上帝》分析了其中的原因和罪魁祸首。所以他们最新的这本看空英国的作品——预测英国将会即刻失去自己的发达国家地位,早已有了一个既定的读者群。Or is that what they claim? The authors do not really suggest that Britains GDP per head will plummet to the levels of sub- Saharan Africa, or that the country will lose the title of “advanced” economy bestowed on it by the International Monetary Fund. Instead, Britains third-world status is signified by a bunch of qualitative factors: “public and commercial services work badly, the average person is becoming poorer rather than richer, the economy has been pulled horribly out of shape and government in the widest sense is hopelessly dysfunctional, with different branches of the state frequently at loggerheads with one another.”他们真的认为是这样吗?其实,作者并不认为英国的人均GDP将会跳水至撒哈拉以南的非洲的水平或者说这个国家将会失去IMF授予的发达国家头衔,而是一些定性因素象征着英国的第三世界状态:公共和商业务乏善可陈,一般人逐渐变得更贫穷而不是更富有,经济已经严重失衡,广义上说来政府运转一塌糊涂——因为国家的不同部门经常相互扯皮。This broad definition allows the pair to be grumpy old men and indulge in some fierce complaining about various aspects of modern British society. At times, it seems as if almost everything is a sign of Britains decline, including the decision to revoke the Syrian ambassadors invitation to last years royal wedding. The Human Fertilisation and Embryology Authority is the subject of a rant, as are the growing powers of Her Majestys Revenue and Customs. Inward investment by China is not a sign of confidence in Britain, but instead dismissed as a token of national humiliation: “What was good enough for the Congo was good for the ed Kingdom.”这个广泛的定义使得两位作者像脾气暴躁的老人一样对当代英国社会的很多方面进行了凌厉的批评。有时,给人感觉好像每一件事情都是英国衰落的写照,包括在去年皇室婚礼上取消对叙利亚大使的邀请。人类受精和胚胎局以及税务海关总署日益膨胀的权力都是被严厉攻击的目标。此外,来自中国的投资在英国被贬低为是国家耻辱而非信心的标志:“对刚果那种国家足够好的东西竟然对英国好。”Despite the authors occasional exaggerations, this is a much more entertaining book than many about economics. And it is hard to disagree with their underlying analysis: “For almost a century, the UK has deluded herself, first into believing that the days of global dominance will return, then into thinking that the symptoms of decline can be relatively easily tackled.” The country has pinned its hopes on a series of fixes—trade preference for other countries in the empire, joining the European Economic Community, North Sea oil, financial deregulation and housing bubbles—that have offered temporary boosts. The current governments growth plan, involving tax incentives for business and cuts in red tape, sounds all too much like some of the failed programmes of the past.除了作者偶尔的夸大之外,这一本书比很多经济方面的书籍都更有趣。并且,作者对其实质的分析几乎不容置疑。“在近一个世纪内,英国都在蒙蔽自己,首先她使自己相信英国称霸全球的日子将会失而复得,之后她使又自己认为英国衰退的症状可以相对轻松地治愈。”英国将自己的希望寄托在一系列小修小补上:给予大英帝国范围内的其他国家贸易优惠,加入欧共体,七八十年代北海石油开采,金融自由化和房地产泡沫,这些都为英国经济提供了短暂的持。当今政府的发展方案包括向企业提供税收激励、遏制官僚作风,这些听起来和过去那些失败的项目十分类似。The recent crisis has shown the dangers of relying on the financial sector, which has gobbled up the cream of Britains university graduates and led to huge inequalities of income and wealth. And despite the Citys overseas earnings, Britain has suffered a persistent balance of payments deficit, a sign that the country is not paying its way.最近的这轮经济危机已经彰显了英国经济过度依赖金融行业的风险:金融行业尽数吸纳了英国大学精英毕业生,并且导致了收入和财富上的严重不均。在伦敦金融城丰厚海外收入的背后,英国却持续遭遇国际收赤字——这一点意味着这个国家入不敷出。For the moment, Britain is a relatively safe haven, with rich Europeans buying up boltholes in London. But the authors are right that serious problems remain—even if the title of this book somewhat overstates the case.在当下,英国仍然是一个相对安全的避风港——很多富有的欧洲人在伦敦买房作避风之用。即使这本书的标题在一定程度上夸大了现实,两位作者指出英国依旧存在的严重问题这点是正确的。201208/192984 What’s So Special About A Sharp Knife?Everyone knows that a sharp knife cuts better than a dull one, but do you know why, exactly?The purpose of the cutting edge of a knife is to concentrate the force that’s being applied at the handle.When you push down on the handle of a knife you exert a force. The force on the handle and the edge are the same, but the areas in which the force is concentrated are quite different.At the handle your hand’s force is sp over a wide area, but on the cutting edge it is concentrated in a very small area, so therefore the pressure on the edge is much greater.You can easily see how this works with a piece of modeling clay, a nail with a wide head, and a nail with a small head. First hold the nail with the wide head by its shaft and push it head-first into the ball of clay. Then do the same with the small-headed nail.The small-headed nail goes into the clay much more easily than the wide-headed nail. Since the head of the small nail has less surface area than the big one, the force of your push is concentrated in a smaller area, exerts more pressure on the clay, and so the nail goes in more easily. The same principal causes pointed high-heeled shoes to sink into a soft surface more easily than flat shoes.By applying this principal to the knife you can see that with a keener edge there’s a greater concentration of the pressure on the edge, so it takes much less force to make the knife cut. /201205/184745于都县人民医院妇科地址赣州市妇幼保健院是公立医院吗



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