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2019年09月19日 04:42:50

Scientists have suspected for many years that fish might giveoff a chemical signal to warn other fish about the presence of predators.多年来科学家们一直都在怀疑鱼会释放一种化学信号来警告其他鱼类捕食者的出现。When a fish in a schoolis injured,比如说,当鱼群中的一条鱼受到伤害时,for example, the rest of the school will panic and swim away in response.鱼群中的其它鱼将会感到恐慌并且四散游开。Scientists dubbed this unknown chemical “Schreckstoff,”科学家将这种未知的化学物质命名为“Schreckstoff”,or “scary stuff” in German,德语译为“令人恐惧的东西”。but theydidnt know what it was composed of until recently.但是直到最近他们才知道这种物质的组成。A major component in fish skin, chondroitin sulfate,鱼的表皮中有一种叫硫酸软骨素的主要成分,appears to be the mystery chemical.似乎就是那种神秘的化学物质。When afish is wounded,当有一条鱼受伤时,this substance is converted by enzymes into sugary molecules that are thenshed into the water.这种物质就会通过酶的作用转化成含糖分子释放到水中。Scientists tested one of those molecules, glycosaminoglycan chondroitin or G for short, onzebra fish.科学家们测试了用斑马鱼释放出来的分子中的其中一个,可称为葡糖胺聚糖硫酸软骨素或简称为G。They found that the sugary warning is detected by special crypt cells in the brainsscent processing olfactory bulb.他们发现这种含糖的警告可以被特殊的隐窝细胞检测到,而隐窝细胞存在于大脑处理气味的嗅球中。This region is directly connected with higher areas of the brainand could initiate a quick flight response in fish.这一区域和大脑更高级的区域相连,可以刺激鱼快速逃跑。Scientists have also found that closely-related species sometimes respond to each others warningsignals,科学家们还发现亲缘关系很近的物种有时也对彼此的警报信号有反应,but unrelated species do not.但是不同的物种就不会有反应。This suggests that there may be a variety of sugary-smellingmolecules,这告诉我们可能会有各种各样闻起来像糖一样的分子,with each species producing their own version.每个物种会产生它们自己的版本。Because the zebra fish brain is relatively simple,因为斑马鱼的大脑构造比较简单,this research is allowing scientists to investigate atthe cellular level what happens in the brain when an organism detects danger.这项研究让科学家们可以在细胞水平上研究当生物遇到危险时大脑的反应机制。It will allow them tosee how groups of neurons regulate behavior and emotional responses.也可以研究神经组织是如何控制行为和情感反应的。Fortunately, fear doesnt smell sweet for humans.幸运的是,人类的恐惧闻起来不像糖。We can enjoy all the apple pie, ice cream, candyand cookies that we want.我们可以尽情的吃我们想吃的苹果派,冰激凌,糖果和饼干。 201403/281872九江县共青城市彭泽县武宁县修水县开眼角多少钱江西省医院纹眉多少钱Bello贝约I, the Supreme我,至高无上Latin America needs term limits. But how strict should they be?拉丁美洲需要任期限制。但是这一限制需要多严格呢?NO SOONER had Juan Manuel Santos, Colombias president, secured himself a second term in a run-off election in June than he announced that he wants to prevent such a thing happening again. He will propose a constitutional change barring immediate re-election and lengthening future presidential terms, from four to five or six years. Why didnt he think of that before, cynics might ask? He might reply that it was in Colombias interest to give him more time to complete peace talks with the FARC guerrillas, for which a single four-year term proved too short.哥伦比亚总统胡安·曼努埃尔·桑托斯刚刚在6月的大选中获得连任机会,便立即发表声明声称他希望防止这样的总统连任事件再次发生。他将提出一个宪法修正案以防止总统再次参与竞选,并将总统任期从4年延长至5或6年。不满的愤世嫉俗者可能会问,为什么他之前就没有想到这么做呢?桑托斯会回答,事实已经明四年的任期并不足以让他完成与哥伦比亚武装力量游击队的和平谈话,为了哥伦比亚的利益他需要更多的时间来完成这一使命。Mr Santoss move runs counter to the regional trend. In country after country in Latin America, term limits have been loosened over the past two decades. The latest to seek to abolish them altogether is Ecuadors president, Rafael Correa. He declared last year that his current term would be his final one, only for his supporters to unveil a bill in July allowing indefinite re-election for all public offices. Since Mr Correa commands a large legislative majority, Ecuador is likely to follow Venezuela and Nicaragua in allowing a presidency for life.Santos先生的做法与拉美整个的地区趋势相悖。在拉丁美洲的各个国家,任期限制在最近的20年里已经一再放松。最近一位想要完全废除任期限制的是厄瓜多尔总统拉斐尔·科雷亚。他去年声称只要他的持者在六月推出允许所有公共政府机关职位的无限期再次竞选的法案,他当前任期将是他最后的任期。由于Correa先生掌握着大多数立法投票席位,厄瓜多尔很有可能和委内瑞拉与尼加拉瓜一样允许终生总统任期。Not coincidentally, these countries are among a handful in Latin America in which presidents now exercise near-absolute power. Mr Correa, the late Hugo Chávez in Venezuela and Nicaraguas Daniel Ortega deployed their electoral majorities to crush the independence of the judiciary, curb the media and hamper opposition. In the extent of their power, if not in the route by which they obtained it, they resemble the regions 19th-century dictators—whose absolutism is captured in the title of a classic Paraguayan novel by Augusto Roa Bastos called “Yo, el Supremo”.并不是巧合,因为这三个国家均是拉丁美洲少数几个总统拥有近乎绝对统治权的国家。厄瓜多尔总统拉斐尔·科雷亚将是下一个委内瑞拉总统乌戈·查韦斯。他和尼加拉瓜总统丹尼尔·奥尔特加部署了大多数选举席位以便遏制司法独立、控制媒体以及遏制反对派的行动。除了获取权利的路线不同,他们的权利范围与该地区19世纪的独裁者有极大的相似之处。这些独裁者的专制统治在巴拉圭作家奥古斯托·罗亚·巴斯托斯的经典小说的标题中体现的淋漓尽致—《我,至高无上》。The trend to looser term limits goes far beyond these three countries. Daniel Zovatto of the International Institute for Democracy and Electoral Assistance, an inter-governmental organisation, points out that in the 1980s the norm in Latin Americas restored democracies was to restrict presidents to a single term. Of the 15 Latin American countries with no plans for indefinite re-election, four now allow two consecutive terms and seven permit former presidents to run again after an interlude. Only four—Mexico, Guatemala, Honduras and Paraguay—still confine their presidents to one term only.放松任期限制的趋势并不仅在这三个国家中存在。国际民主与选举援助组织在拉丁美洲和加勒比海的区域主管丹尼尔·组瓦特指出,拉丁美洲于20世纪80年代恢复的民主政治正是为了将总统职位限制为单任期。在15个尚没有允许无限期再次竞选的拉丁美洲国家中,4个国家现在允许2期连任,有7个国家允许前任总统们在他人担任总统之后再次竞选总统,只有墨西哥、危地马拉、洪都拉斯以及巴拉圭这4个国家依旧将总统限制为单任期。Critics of this trend say that incumbents have an even greater advantage over opponents than they have in, say, the ed States. Only twice since 1990 have candidates who were sitting presidents lost elections in Latin America. Several incumbents have also managed to anoint their chosen successors, who in the case of the late Néstor Kirchner of Argentina was his wife, Cristina Fernández de Kirchner.这种趋势的批评者认为,现任总统相比于其反对者的优势很大,且这种优势甚至还大于北美总统的优势。自1990年以来,现任总统再次竞选失败的事情在拉丁美洲只发生过两次。有些在位者也会神话他们选定的接任者,比如阿根廷前任总统内斯托尔·卡洛斯·基什内尔便扶持他的妻子克里斯蒂娜·费尔南德斯·德基什内尔成功接任总统。But the recent success of incumbents owes much to their good fortune in presiding over a golden decade of commodity-fuelled economic growth, and in their distribution of some of this windfall to the poor. Now that economic growth has slowed, presidents have become less popular. A test of whether incumbents remain near-invincible will come in Brazils election in October, in which Dilma Rousseff faces a tough fight for a second term.不过在位者们的近期成功主要应该归功于他们幸运地处在大宗商品经济蓬勃发展的黄金时期,他们只要将一部分“上帝的馈赠”分发给穷人便可以获得持。而现在经济的增长速度放缓,总统们变得并没有那么受欢迎。今年10月,在巴西的选举中将会有一个关于在位者是否依旧无可匹敌的测试进行,在这次选举中迪尔玛·罗塞夫为了自己的第二任期将会面临一场艰难的竞争。There are, in fact, some sound reasons for allowing re-election—though not indefinitely. If a president is popular and has done a good job, surely voters should have the right to choose him or her again? A four-year term, as eight countries have, is too short to do much. Indeed, it is not all that long ago that political scientists fretted that Latin American presidents were too weak rather than too strong.事实上,还是有一些合理的理由允许总统再次参加竞选的,虽然不是无限再次竞选。如果一个总统很受欢迎并且工作出色,选民们难道不应该有权利再次选择他或者她吗?现在拉丁美洲有8个国家依旧维持4年为一任期的规定, 4年时间确实不足以让一个总统完成太多事情。而且就在不久之前,政治学者们甚至认为拉丁美洲的总统们太脆弱而不是太强大。What matters is not whether a president can run for re-election, but whether countries possess the countervailing institutions required to curb the abuse of executive power and the advantages of incumbency. Strong and independent judiciaries, electoral authorities, media and political parties are all vital.问题的关键点不在于总统是否可以再次竞选,而在于国家是否有足以遏制滥用行政权力和在位者优势的对抗制度。强大而独立的司法机构、选举委员会、媒体以及政党都是必不可少的。Paradoxically, Colombia is fairly well-served in this regard. Its constitutional court knocked down an attempt by álvaro Uribe, Mr Santoss popular predecessor, to run for a third consecutive term. Mr Santos told Bello during the campaign that he thinks Colombians dislike re-election, initiated in 2006 by Mr Uribe. That may be one reason why he barely squeaked to a second term, winning the run-off by less than six percentage points. It seems that Mr Santos has come up with a solution to a problem that Colombia doesnt really have. Perhaps he should export it to Ecuador.反常的是,哥伦比亚在这一点上做的很好。其宪法院成功粉碎了Santos先生的上一任总统乌里韦谋求3连任的企图。在此次竞选中,桑托斯先生告诉贝约,他认为自乌里韦于2006年连任总统以来,哥伦比亚不喜欢总统再次参加竞选。这恐怕也是本次竞选中他以少于6%的微弱优势艰难胜出的原因之一。看上去桑托斯已经想到了解决问题的方法,虽然这个问题在哥伦比亚并不存在。或许他可以将这个方法推荐给厄瓜多尔。 /201408/319478How money works钱是如何运作的Gold rush淘金热A good guide to the stuff in our pockets一本关于我们囊中物的优秀指南Money: The Unauthorised Biography. By Felix Martin.《金钱:非授权自传》。作者:Felix Martin。ONE story in this surprisingly entertaining book on the nature of money is about the Irish banking crisis. The countrys bank system ground to a complete stop, with branches closed, the clearing system suspended and customers unable to withdraw or deposit money. As cash ran out, people had to find a way of paying their regular bills, or even just stumping up for a pint of stout in a pub. What actually happened was that businesses started accepting IOUs or cheques for everything, even though there was no telling when the cash would be forthcoming. It helped that a lot of Irish life is lived locally: builders, greengrocers, mechanics and barmen all turned out to be dab hands at personal credit profiling.这本关于金钱性质的书出乎意料地有趣,其中一个故事与爱尔兰危机有关。爱尔兰的系统完全瘫痪,各分行全部关闭,清算系统被暂停,顾客无法存取款。在现金用完后,人们不得不想办法付日常账单,就连在酒吧为一品脱烈性黑啤埋单也是如此。结果商家开始接受欠条或票,虽然没人知道现金何时会来。还好爱尔兰人的生活起居很大程度上都可以在当地解决:建筑工、零售店主、机械师和酒保摇身变成了个人信用建档的行家 。In short, Ireland developed a new class of money. Its currency was not backed by any central bank, but based solely on informal if surprisingly accurate credit scoring. And the currency was transferable: if certain people said the bond was good, then the bond was good.总之,爱尔兰发展出一种新的钱种类。其货币不被任何央行持,仅仅基于非正式却出奇准确的信用记录。并且这种货币是可流通的,如果某些人说债券有效,那么债券就有效。This particular Irish banking crisis might seem vaguely familiar, but only vaguely. It took place more than 40 years ago, when the Irish financial sector came to a seven-month halt as a result of a national labour dispute. The point of the story is that it supports two of the authors main contentions—first that money is not currency and that sovereign support for currency is not particularly important, and second that financial crises are endemic. No sooner has the last one been put to bed than the next is waking up.这个奇特的爱尔兰危机听起来可能隐约有些熟悉,但也只是隐约而已。那次危机发生在40多年前,当时爱尔兰金融业因全国劳动争议瘫痪了七个月。讲这个故事是因为它持了作者的两点主张——第一,钱不是货币,并且主权对货币的持并非特别重要;第二,金融危机是普遍的,刚刚解决一个危机,另一个危机又出现了。For some people, money is merely something underwritten by the state and designed to enhance a basic barter economy. Felix Martin, an economist and fund manager, goes further. Early societies, such as the Babylonians and the ancient Egyptians, were static, with a fixed hierarchy of social obligations. They had no need of money or currency. Money was the instrument through which later societies unshackled themselves from preordained social orders and became individualistic.对于一些人来说,金钱仅仅是国家担保的东西,用于增强基本的物物交换。经济学家、基金经理Felix Martin对金钱的理解更进了一步。早期社会,例如巴比伦和古埃及,是静止的,每个阶层承担的社会责任固定不变。这些社会不需要金钱或货币。金钱将之后的社会从上天安排的社会制度中解放出来,变为个人主义。With money came speculation, bringing in turn those endemic financial crises. To ensure greater stability, Mr Martin would like to see the introduction of an ultra-simple version of “limited-purpose banking”. Money must be “shorn of its specious promise” he says; let the state underwrite a tiny core of deposit-taking banks. Everything else—from interest-rate derivatives to collateralised debt obligations should carry on unregulated and uninsured. If you lose your dough, tough. You knew the risks. It is a solution that will attract anyone seeking a clean, clear, fair way of managing financial markets. Until they lose their money, of course.有金钱就有投机,有投机就有普遍的金融危机。为确保稳定性,Martin希望引入超简版的“限制用途”。他说,必须“去除”金钱“似是而非的承诺”;让国家为储蓄极少的核心业务担保。其他业务—从利率衍生工具到债务抵押债券—应继续不受监管,不受保护。如果你输了钱,糟糕。不过你本来就知道风险的。这个解决方法会吸引寻求以干净、清楚、公正的方式管理金融市场的人。当然在他们自己输钱以前。 /201405/294177上饶背部脱毛

景德镇打botox要多少钱九江市都昌县湖口县自体脂肪隆鼻价格In early medieval France, the Count of Anjou became enthroned by a mysterious woman.在中世纪法国的早期,昂儒伯爵因为一位神秘的女性而登上王位。They married and had several children.于是他们结婚并且有了几个孩子。But the Count grew concerned because his wife always left church before Mass was celebrated.但昂儒的担心日渐增加,因为他的妻子总是在庆祝仪式开始前离开教堂。One day he ordered his knights to stop her.有一天,他命令自己的骑士们阻止她这样的行为。But she pulled free and flew out through a window.但她巧妙脱身并且从窗户飞走。The Countess of Anjou was never seen again.自此再也不曾见过伯爵夫人的踪影。According to this legend, all 15 Plantagenet kings of England were descended from the demon Countess of Anjou.按照这个传说,所有15位英格兰金雀花王朝国王都是恶魔伯爵夫人的后裔。Her blood flowed in their veins.她的血液在这些后代身上流动。And over the centuries, this provided an explanation for the fierce temper, the bloody family feuds and the brutality of the Plantagenets.而几个世纪过后,这种血缘关系或许就是金雀花王朝火爆脾气,家庭不和以及冷酷无情的原因。Richard the Lionheart himself once declared defiantly, ;From the Devil we came, and to the Devil we will go.;狮心王理查自己曾公然宣布,“我们是魔鬼的化身,魔鬼去哪里我们就去哪里。”In the medieval world, all politics was family politics, and the Plantagenet family dominated England for more than 300 years through some of the nations most famous and infamous kings.在中世纪的世界中,所有政治都是以家族为中心,在统治英国的300多年中,金雀花王朝家族涌现出最著名及最臭名昭著的国王。King John. Henry V. Richard III.约翰。亨利五世,理查德三世。They were driven by dynastic ambition, striving to expand their power beyond their French homeland.他们被王朝的野心驱使,努力扩大自己超出法国国土的力量。201407/309551南昌同济整形祛疤手术多少钱Science and technology科学技术Genetically modified tree转基因树木Into the wildwood进军森林A GM species may soon be liberated deliberately一种转基因树木不久或将大量种植,但很审慎ONCE upon a time, according to folklore, a squirrel could travel through Americas chestnut forests from Maine to Florida without ever touching the ground.民间流传有这样的故事:很久很久以前,松鼠在穿过美国缅因州到福罗里达州的栗树林时,可以一直不触碰地面。The chestnut population of North America was reckoned then to have been about 4 billion trees. No longer.估计北美那时的栗树约有40亿棵。现在却不复存在了。Axes and chainsaws must take a share of the blame.必须说,斧头锯子不乏其罪,But the principal culprit is Cryphonectria parasitica, the fungus that causes chestnut blight.但栗疫病菌才是罪魁祸首,是这种真菌致栗树感染了栗疫病。In the late 19th century, some infected saplings from Asia brought C. parasitica to North America. By 1950 the chestnut was little more than a memory in most parts of the continent.19世纪后期,一批亚洲来的感染栗疫病菌的树苗把该病菌带到了北美。到了20世纪50年代,北美大陆大部分地区的栗树便全部消失,成为了回忆。American chestnuts may, however, be about to rise again—thanks to genetic engineering.但有了基因工程,美国栗树有望再次繁茂起来。This month three experimental patches will be planted, under the watchful eye of the Department of Agriculture, in Georgia, New York and Virginia.在美国农业部的密切看护下,将于本月在乔治亚州、纽约州和弗吉尼亚州分别栽种一片栗树林进行实验。Along with their normal complements of genes, these trees have been fitted with a handful of others that researchers hope will protect them from the fungus.这些栗树除携带正常的附加基因外,还添加了少数不同寻常的附加基因。研究者希望通过添加这些基因来防止栗树被真菌感染。The project has been organised by the Forest Health Initiative, a quango set up to look into the idea of using genetic engineering to rescue species of tree whose populations have been devastated by fungal diseases or insect pests.该项目的组织者是一个半官方机构—森林健康行动,该机构的创立是为了检查用基因工程来拯救被真菌病或害虫摧毁的树木种群的可行性。It has sponsored research at several universities, and this months trial is the first big field test.FHI已在几所大学发起了研究倡议,并于本月迈出大型实地试验的第一步。If it works, the FHI will ask the government for permission to plant transgenic chestnuts in the wild, with the intention of re-establishing the species in Americas woodlands.如果可行,FHI则会向政府申请在自然环境中种植基因改良栗树,以重建美国林地的栗树林。And if that goes well, it could provide a model for projects to re-establish elm trees, ash trees and a fir tree known, confusingly, as the eastern hemlock.如果这也可行,那就能为榆树、白蜡树和杉树重建项目提供示范。The search for genetic protection for the chestnut was begun in 1990 by William Powell of the State University of New York, in Syracuse, and Scott Merkle of the University of Georgia, in Athens.栗树基因保护研究始于1990年,由锡拉丘兹市纽约州立大学的威廉·鲍威尔和爱森斯市乔治亚大学的斯科特·默克尔共同进行。Dr Powell knew that many of the symptoms of chestnut blight are caused by the oxalic acid that C. parasitica generates as it grows.鲍威尔确信,栗疫病的很多症状都由栗疫病菌生长时产生的草酸引起。He also knew that wheat has an enzyme called oxalate oxidase, which detoxifies oxalic acid.他也清楚,小麦有一种草酸氧化酶,能够分解草酸。He and his team therefore transferred the gene that encodes oxalate oxidase from wheat to chestnut.于是,鲍威尔和他的团队将小麦中能够编码草酸氧化酶的基因转移到了栗树的基因中。Last summer they showed that oxalate oxidase can indeed enhance blight-resistance.去年夏天,他们明了,草酸氧化酶的确能够增强栗树的抗枯萎性。A few years ago the Forest Health Initiative asked Dr Powell and some other researchers doing related studies to look at the work of the American Chestnut Foundation, a group which had been crossbreeding Chinese and American chestnuts.几年前,FHI邀请了正在进行相关研究的鲍威尔士和另一些研究者研究美国栗树研究基金会的工作。Since C. parasitica is Asian, Asiatic trees have evolved resistance to it. The foundation hoped to make a hybrid sufficiently Chinese to be protected, but sufficiently American to pass muster as local.由于栗疫病菌发于亚洲,亚洲树种已经形成了对该真菌的抗性。With the aid of the genomes of the two species, Dr Powell and his collaborators began testing 27 Chinese chestnut genes in the American tree.借助两种栗树的基因组,鲍威尔士及其合作伙伴开始在美国生长的树上测试27种板栗基因。The 800 trees to be planted this month will contain various combinations of these genes, the original wheat gene and six further genes from other tree species.本月将栽种800棵树,这些树包含了原小麦基因以及其他树种6种基因的各种组合基因。And results should come quickly.预计结果很快就可以得出。Field tests for blight-resistance are typically done when trees are a few years old, but Dr Powells team have devised a test of the saplings leaves that they believe can tell whether a tree is resistant when it is less than a year old.抗枯萎性的实地试验一般要当树木生长几年之后才能进行,但鲍威尔士研究小组想出了一个测试树苗叶子的办法,他们认为可以在树龄不满一年的情况下测试出树的抗性。The trial itself will last three years, and the researchers running it will monitor how the modified chestnuts fit in to the local ecosystem, as well as how healthy they are.这项试验会进行三年,进行该试验的研究者将持续观察记录改良过的栗树在当地生态系统的适应程度以及它们的健康状况。If they both do fit and are fit, a decision will then have to be made about whether to release them into the wild. That will be up to the Department of Agriculture, the Environmental Protection Agency and the Food and Drug Administration.如果能够适应并且长势良好,那是否要在自然环境中大量种植就得由农业部、环境保护署和食品药品监督来决定了。Until now, the genetic modification of trees has had strictly commercial aims: speeding up the growth and extending the environmental tolerance of species intended for plantations.迄今为止,改良树木基因带有明确的商业目的:一是催长,二是为了造林增加物种对环境的容忍度。This use of genetic modification has been opposed by environmentalists, who fear that such supertrees may escape and damage wild forests.为达到该商业目的使用转基因,遭到了环保主义者的反对,他们担心这样的超级树会疯长进而危害到野生丛林。The Forest Health Initiatives goal, though, is to heal wild forests, not hurt them.但FHI的目标是为了恢复而不是危害野生丛林。If its experiments do produce a strain of chestnut that could do the job, it will be interesting to see how enthusiastically greens embrace it.如果试验成功,真能培育出抗栗疫病菌的新品种,那看看环保党在欣然接受时会表现出怎样的欢欣鼓舞,还挺有意思的。 /201311/266596南昌市中医院整形科

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