楼主:光明新闻 时间:2019年09月18日 19:24:52 点击:0 回复:0
During the last ice age, rapid swings in temperature occurred within decades or less, meaning populations of organisms had to adjust quickly to new environments or face extinction.在最后一个冰河世纪中,温度在数十年甚至更短的时间内迅速变化,这意味着生物种群不得不快速调整来适应新的环境,否则等待它们的只有种族灭绝。Scientists knew there wasnt time for the genetic code to mutate within individuals and sp throughout large populations. So, how did animals respond? Ancient bison preserved in the Canadian arctic have given scientists a clue.科学家知道那时基因编码没有时间在个体中产生变异并在种群中大范围地传播。那么,动物们是如何应对的?在加拿大北极圈内保留的古代野牛标本给科学家们提供了一些线索。When genes were first identified, scientists thought they were hard wired. One gene made one protein and was unalterable. Today we know the story is much more complex. Part of that complexity is known as epigenetics, a process by which genes are modified by environmental factors.第一次识别古代野牛的基因时,科学家们认为它们是固定相连的。一个基因对应一个蛋白质并且无法改变。如今我们知道故事远没有那么简单。其中一部分复杂性来自表观遗传学,它是基因通过环境因素发生改变的过程。The genetic code stays the same, but certain molecules attach to the code to prevent specific genes from working or to change how they are expressed. Other molecules can affect the chromosome and alter the way the DNA unwinds, affecting how genes work.基因密码保持不变,但是某个为阻止某个特定基因工作或变更的密码附属分子发生了变化。而其它分子可以通过影响染色体并改变DNA解旋的方式来影响基因的表达。Extracting DNAScientists examining twenty six thousand year old bison bones looked for evidence of epigenetic changes in extracted DNA. They analyzed the genetic code for a particular kind of epigenetic change called DNA methylation. They not only found methylations, they found them in locations where they occur in modern cattle. That suggested they werent due to DNA degradation, but were true epigenetic changes.DNA提取科学家检查了已有26000年历史的古代野牛的骨头,试 图在提取的DNA中找到表观遗传变异的据。他们分析了一种特定种类的表观变化(被称为DNA甲基化)的基因密码。他们不但找到了甲基化,而且发现它们跟 现代牛群体内发现的位置是一样的。这表明它们不是发生了DNA退化,而是真正的表观遗传变异。This is just the first step in solving the ice age adaptation puzzle. Scientists plan to gather more DNA samples from animals that lived before and after the dramatic climatic shifts. That way theyll have genetic snapshots to compare. If comparisons prove successful, the next step will be to determine exactly how the epigenetic alterations changed the gene expression.这仅仅是解决冰河世纪适应谜团的第一步。科学家计划在气候剧烈变化前后生存过的动物身上收集更多的DNA样本。如此一来,他们就有更多的基因用来比较。如果比较的结果明是之前的推断是正确的,那么下一步是确定表观变化是如何影响基因表达的。 /201305/240484This is a Jew.这是个犹太人。And so is this.这位也是。This is a Jew, and this, and this. And so am I.这是犹太人,还有这位,这位。我也是。So, what, if anything we have in common?那么,我们有什么共同之处?Not the color of our skin,not the languages we speak, the tunes we sing, the food we eat.不是我们皮肤的颜色,不是我们所讲的语言,我们歌唱的曲调,我们吃的食物。Not our opinions where we fiercely argued a lot, not even the way we pray,assuming we do.不是我们强烈认为很多的意见,,甚至不是我们祷告的方式,我们所做的假设。What ties us together is a story, a story catching our heads and hearts, a story of suffering and resilience, endurance and creativity.将我们联系在一起的是一个故事,一个使我们使我们身心为之动容的故事,一个充满痛苦和恢复力,耐力和创造力的故事。Its the story that make me want tobe in the story in the first place,这是故事中的故事,让我想首先辗转反侧,for I understood but I was quite small that there were two special things about the Jews,that we had endured over 3,000 years in spite of everything that has been thrown at us,因为我明白了,但是我仍然非常渺小,因为两个犹太人的特殊事情,我们已经经历了3000多年,尽管诸事已经抛给我们的,and that we had extraordinary dramatic stories to tell and somehow that these two things were connected that we told our story to survive.我们有着戏剧性的故事,在某种程度上,这两个事物联系在了一起我们告诉我们的故事才能生存。We are our story.我们就是我们自己的故事。201402/277839

Cuba and the outside world古巴及世界Rekindling old friendships旧友重拾Cuba is once again resorting to geopolitics to support a failing economy古巴再次诉诸地缘政治,以撑其低迷经济CARLITO, a wiry man with greying hair, sits under a palm tree in Mariel, a town on a bay 40km west of Havana, sipping rum and watching a container ship edge out towards the Caribean. He recalls seeing a flotilla of smaller boats leaving from this same spot in 1980, carrying thousands of opponents of the Castro regime to Florida in the “Mariel boatlift”.Carito满脸疲倦,头发花白,静坐在马里埃尔镇的一棵棕榈树下,这一海湾小镇距离哈瓦那40千米,他抿一口朗姆酒,目送着一只载着集装箱的货船起锚驶向加勒比海,1980年的回忆袭上心头,当时一组略小的船只同样从这里起航,满载着成百上千的卡斯特罗政权的反对者,偷偷从马里埃尔驶向弗罗里达,Those were politically charged times. Government trucks would come to his school to deliver eggs for him and his friends to throw at the people fleeing. About a decade and a half later, after the collapse of the Soviet Union in 1989 plunged Cubas economy into crisis, sources of protein were so scarce that Carlito recalled those wasted eggs with bitter regret. Some “Marielitos”, as those who fled are known, returned recently and Carlito was stunned at how prosperous they had become. “We used to call them traidores (traitors),” he chuckles. “Now we call them traedolares (bring dollars).”当时政治斗争风生水起,政府的卡车会装载着鸡蛋来到他的学校,供他和他的朋友扔向那些逃亡的人群,但15年后,苏联解体,将古巴的经济一举推向危机的深渊,连蛋白质也成了珍稀产品,一想到当年浪费的那些鸡蛋,Carlito无不扼腕叹息。近来,一些当年逃走的所谓Marielitos的人重回古巴,他们的富有让Carlito大跌眼镜,他打趣儿的说,当年我们损他们为卖国贼,现在则称他们是生财佬。Across the bay from where Carlito sits is a 900m container port, which was built with Brazilian money and inaugurated in January. There are plans to develop a special economic zone alongside it, modelled on the thriving export hubs, such as Shenzhen, that China developed from 1980 onwards. The port is part of a vision for Cuba that relies less on Cuban-American gusanos (worms) sending remittances to prop up the local economy, and more on an inflow of foreign investors.穿过Carlito静坐的海湾,一个造价9亿美元的集装箱港跃入眼帘,该港口以巴西货币为经费,1月投入使用,计划是在其周边建设特别经济区,以一些蒸蒸日上的出口中心如深圳——1980年后中国腾飞的城市为模板,这一港口是古巴减轻对古巴裔美国人依赖计划的一部分,不完全指望他们为当地经济发展投入经费着力引进更多的外来投资。But Carlito is keeping his excitement in check. Construction workers building the container terminal were paid a mere 250 pesos a month, he says, so the ramshackle town has yet to benefit from the development. None of the 23 firms who have sought licences to operate in the special economic zone has yet been granted one. Even Joaquín Infante, the 88-year-old vice-president of the slow-moving National Association of Cuban Economists and Accountants, urges speedier authorisation of investment. “We need to be more flexible and take more risks,” he says.但Carlito并未喜出望外而是坐而观望,他说,建造集装箱港口的工人的月薪仅为250比索,这相对于扶持起一个摇摇欲坠的城镇来说无异于杯水车薪,尽管已经有23所公司申请了特别经济区的经营执照,但无一成功。即使是在步履蹒跚的古巴经济学家和会计师协会,88岁的副会长也要求对投资尽快审批,他说“我们应更加灵活机动,不畏风险。”Despite reforms that have brought some big changes to Cuba in the form of private restaurants, bed-and-breakfasts and new co-operatives, the economy has virtually ground to a halt. In the first half of the year GDP grew by just 0.6%, leading the government to reduce its estimate for full-year growth to 1.4%. That is lower than the 2.7% annual average figure since Raúl Castro (pictured on the right, with Vladimir Putin) became president in 2008.虽然改革带来了很大的机遇,古巴迎来了一些私人餐馆,住宿早餐包揽的旅馆和新的企业,但其经济发展停滞不前,今年上半年古巴的GDP增长仅为0.6%,这促使政府将全年增长预期调低至1.4%,这比卡斯特罗自2008年上任以来的年均数据2.7%还要低。Investment is the root of the problem. In a report in July, two Cuban economists, Omar Everleny and Ricardo Torres, estimated that the growth in Cubas capital stock, such as machinery and buildings, fell to 7.8% of GDP last year, close to its level of 5.4% in 1993 when the economy was in serious trouble. From the 20th floor of the Habana Libre, a run-down hotel, not one crane can be seen on the skyline. “The economy is screwed,” says a Havana-based diplomat.问题的根源在于投资,在7月的一则报告中,两名古巴经济学家奥马尔和里卡多预测诸如在机械和建筑领域的股本下跌至占GDP的7.8%,与1993年该国经济正处泥潭中的水平基本持平,从哈瓦那棚户区的一家旅馆的20层楼上观望,目光所及的天际之下,无一架起重机,哈瓦那的一名外交人员说,放眼国家经济,只让人眉头紧锁Supporters of the regime argue that the reforms simply need more time. A profit-oriented reorganisation of state-owned behemoths, such as the sugar monopoly, could be promising; it is just that the bureaucrats who run them are slow to change. Critics, however, see a fundamental flaw in the reform model. Although it has sought to give some people more freedom in what they make and sell, the state keeps a stranglehold on the inputs they need for those businesses, such as seeds for growing crops, or sauces and spices for restaurants, or spare parts for taxis. It has cracked down on “mules” bringing in such goods on passenger planes from abroad.政权的持者说,改革不过是需要更多的时间,以盈利为导向重组例如制糖垄断的国企大亨前景甚好,只是运营的官僚机构老牛破车,然而,批评人士认为,改革方略中存在根本性漏洞,虽说国家给予了人们制作和销售的更多的自由,但却严格限制做生意所需原料的进口,如粮食种子,餐馆的调味汁和香料或出租车的备件,他也严厉打击用客机从国外偷运这些商品的人。Diplomats say such counter-measures will make it harder for Cuba to attract the 2.5 billion in annual foreign investment that the regime aims for. Some also reckon the financial squeeze on the island has tightened this year in the wake of the case against BNP Paribas, a French bank, for evading American sanctions on doing business with Cuba, among other places.外交人员称在这些打击措施下,古巴更难实现年外资吸收达25亿美元的目标,一些人估计,对抗法国BNP Paribas事件使得今年的财政困难雪上加霜,该事件是为了躲避美国对其他地区实施的与古巴通商的制裁。That is why Cuba-watchers have paid close attention to the visits of Russias president, Vladimir Putin, and Chinas leader, Xi Jinping, in recent weeks. Though both men offered few concrete investments in Cuba, they provide an opportunity for the Castro regime to start reducing its dependence on its closest ally, Venezuela, whose pro-Cuba government has been rocked by instability this year. Says Mr Infante: “We have to diversify and not depend on just one partner.” He hopes that means more Chinese and Russian investment in Mariel.因此,持观望态度的投资者对近几周俄罗斯总统普京和中国国家主席习近平的来访甚为关注,虽说两人提供的实际投资不过寥寥,但这至少给卡斯特罗政权提供机会,减少对他亲密战友委内瑞拉的依赖程度,但该国持古巴的政权今年也在动荡中下台,infante说,我们应建立多元伙伴关系而不是依靠单独一个,他希望马里埃尔港能迎来更多来自中国和俄罗斯的投资。One envoy says the regime also prefers such investments to Western capital because it sees neither China nor Russia as a “Trojan horse” working towards regime change. A Cuban economist sees uncanny parallels with the special terms offered to the Soviet Union in the cold war. “The mentality of the decision-makers is to talk to Russia, talk to China, and make them offers based on politics,” he says. “But this is the same mentality we had in the past…and it didnt do much for productivity.”一位使者称该政权也希望能给西部首都带来同样的投资,因为他认为俄罗斯和中国的投资都不是“特洛伊木马”,企图推动政权更替,一位古巴的经济学家称在冷战期间针对苏联的措辞与此如出一辙,不可思议,他说;“决策者希望与俄罗斯和中国实现交流,使他们基于政治因素作出投资,但这不过是老调重弹,鲜有成效。”Cubas courtship of Russia is particularly striking: a day after Malaysian Airlines flight MH17 was shot down, Fidel Castro publicly blamed Ukraines government. Such an overtly pro-Russian stance on Ukraine may hinder political negotiations that started this year between Cuba and the EU, diplomats say. It also makes it harder for Barack Obama to improve Americas relations with Cuba, let alone consider an end to the counter-productive 54-year-old embargo. Back in Mariel, Carlito wants good relations with everyone, especially America. “Luckily we Cubans have a lot of patience and patience is good,” he says. “Without it theres just frustration.”古巴对俄罗斯的巴结尤其让人嗔目结舌,马航飞机MH17击落一天后,卡斯特罗便公开谴责乌克兰政府,外交人员说,它在乌克兰问题上公开持俄罗斯的立场可能会影响今年他与欧盟的政治对话,此外,奥巴马会更不情愿改善两国关系,更别提结束长达54年的禁运,虽说其效果是适得其反。卡斯特罗希望马里埃尔能与所有国家建立友好关系,尤其是美国,他说,幸运的是我们古巴人民锲而不舍,否则便只有槁木死灰。 /201408/320721

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