首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
It was a sorry end. Cut down in his prime, the cunning thief lay on the slab, his cold body offering pathologist Brett Gartrell
It was a sorry end. Cut down in his prime, the cunning thief lay on the slab, his cold body offering pathologist Brett Gartrell
admin
2009-06-24
28
问题
It was a sorry end. Cut down in his prime, the cunning thief lay on the slab, his cold body offering pathologist Brett Gartrell no outward sign of how he. had met his maker. Once Gartrell had wielded his scalpel, however, the cause became, clear: a belly stuffed with sticky brown gunk. Diagnosis? Death by chocolate.
66.______
If you’re reading this after scoffing your fifteenth chocolate Santa, don’t panic: We humans have been safely enjoying the beans of the cacao plant, Theobroma cacao, for millennia. Theobroma is Greek for "food of the gods", reflecting the Mayan belief that cocoa had divine origins. Every April, they sacrificed a dog with cacao-coloured markings in honour of Ek Chuah, the god of cacao.
67.______
It was methylxanthines that did for the kea too. Gartrell, a wildlife pathologist at Massey University in Palmerston North, New Zealand, is wearily familiar with keas’ propensity m poison themselves. Besides being arguably the world’s smartest birds, keas are extraordinarily inquisitive foragers, using their beaks to rip open tents and backpacks, open garbage bins and even pry pieces off cars in their quest for food. "They’ll try anything that is vaguely edible, which is part of the reason they get into trouble", says Gartrell.
68.______
The reason humans don’t turn up their toes after bingeing on chocolate is largely down to the speed at which our bodies metabolise theobromine, the most abundant methylxanthine in chocolate. Rats metabolise it much more slowly than humans, and dogs are slower still. There are no reliable figures for theobromine toxicity in humans, but based on caffeine toxicity an average adult would have to gorge on around 50 kilograms of milk chocolate in a single sitting to get anywhere near a lethal dose.
69.______
Coyotes are a serious pest in the U.S., killing $44 million worth of livestock each year, damaging property and attacking people and pets. Measures such as fences are often ineffective. Sometimes culling them is the only option but unfortunately the poisons now used, such as sodium cyanide, are toxic to humans and most other animals too. "If we can come up with something that is more selective, it offers an advantage", says Johnston. "It’s a more responsible approach".
70.______
Methylxanthines are also shaping up as a way to dispatch other pests. Earl Campbell of the U.S. Pacific Basin Agricultural Research Center in Hilo, Hawaii, discovered that caffeine sprays could kill two species of noisy and ecologically damaging Caribbean tree frogs that have plagued the island since they were accidentally introduced in the 1980s. Campbell noticed that the spray also killed slugs. His colleague Robert Hollingsworth then found that caffeine spray made snails kick the bucket too. Hollingsworth is now developing caffeine as an alternative to conventional pesticides, such as those used in slug pellets. "There’s a huge amount of interest in using botanical extracts", he says. "People are more comfortable with things that are natural".
A. Knife-wielding priests aside, chocolate is still bad news for many animals. Cocoa beans are naturally rich in caffeine and its chemical relatives theobromine and theophylline, collectively called methylxanthines. To humans these are little more than benign stimulants, but to a number of animals they are highly toxic. Just 240 grams of unsweetened dark chocolate contains enough methylxanthines to kill a 40-kilogram dog, about the size of a German shepherd.
B. The methylxanthines are just a start. "Cocoa is a real gold.mine of different components", says Herwig Bernaert, research manager at Barry Callebaut, a chocolate manufacturer in Zurich, Switzerland. Cocoa contains more than 700 compounds and there is a great deal of research on which of these can affect people or other creatures.
C. Methylxanthines looked as though they might fit the bill. After testing the toxicity of several different types of chocolate, Johnson came up with a mixture of theobromine and caffeine that killed coyotes quickly and with minimal distress. The mixture can be hidden in bait and is currently undergoing field tests.
D. The observation that methylxanthines are highly toxic to animals, with dogs being especially vulnerable, prompted John Johnston, a chemist at the U.S. Department of Agriculture in Fort Collins, Colorado, to investigate chocolate as a more selective way of controlling coyotes.
E. Divine—yes. Delicious—absolutely. But deadly? For some it certainly is. The corpse on Gartrell’s slab belonged not to a human but to a kea, an endangered New Zealand parrot. Like many animals, keas are acutely sensitive to chemicals in chocolate that are harmless to humans in all but huge doses. Scientists are now studying these chemicals, along with other substances in cocoa, hoping to exploit their toxic effects to control pests or microbes.
F. The dead kea was found outside a hotel kitchen in the holiday resort of Mount Cook Village in the Southern Alps. It had eaten more than 20 grams of dark chocolate, presumably pilfered from the kitchen garbage. "He’d really pigged out", says Gartrell. The ill-fated kea was by no means alone in its folly. Veterinary journals are peppered with stories of dogs, cats, parrots, foxes, badgers and other animals dropping dead after finding chocolate or being fed it by well- meaning humans.
选项
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/9zTd777K
本试题收录于:
公共英语五级笔试题库公共英语(PETS)分类
0
公共英语五级笔试
公共英语(PETS)
相关试题推荐
TheHistoryoftheFridge1.Thefridgeisconsideredanecessity.Ithasbeensosincethe1960swhenpackagedfoodfirstapp
AttentiontotheDetails1Attentiontodetailissomethingeveryonecanandshoulddo-especiallyinatightjobmarket.Bo
"Othercountrieshaveaclimate;inEnglandwehaveweather".ThisstatementsuggeststhatAspecialfeatureoftheweatherin
Thephrase"theworld"inthefirstlineofthepassagereferstoAccordingtothepassage,wecanavoidaworldwidewatershor
TheauthorofthepassagecouldnotgotosleeppartlybecauseWhatwastheweatherlikethatnight?.
ForestsforCitiesYouarestandinginabeautifulforestinJapan.Theairiscleanandsmellslikeplantsandflowers.Ther
HaveYouFilledUpTheForm?Ofallthingsintheworld,Imostdislikefillingupforms.Infact,Ihavea【C1】______horror
A.todiscoversentencepatternsandgrammaticalrulesB.toexpandvocabularyC.tousethetargetlanguageD.toencourageunsucce
Theconferenceexploredthepossibilityofclosertradelinks.
TheInternetHouseAleadingBritishbuildinganddesigncompanyhasjustannouncedtheirplansforthehomeofthefuture.T
随机试题
Manypeoplewronglybelievethatwhenpeoplereacholdage,theirfamiliesplacetheminnursinghomes.Theyareleftinthe【C1】
A、Herrigoroustrainingindeliveringeloquentspeeches.B、Herlifelongcommitmenttodomesticandglobalissues.C、Hewidesprea
关于睾丸肿瘤的论述,下列哪项是正确的
女,20岁,近1个半月来干咳伴有低热,自觉乏力。听诊右上锁骨下区有固定的湿啰音。怀疑其肺结核。病人在治疗过程中,判断结核化疗效果,最重要的指标是()。
女性,25岁,未婚,妇科检查发现右侧附件区4cm囊性包块,活动佳。血清CA12520U/ml,B,型超声为单房囊性肿中物,此例最可能的诊断是
患者心中烦热,急躁失眠,口舌糜烂疼痛,口渴,舌红,脉数,经诊断为()。
双代号网络计划中,如果计划工期等于计算工期,且工作i-j的结束节点j在关键线路上,则工作i-j的自由时差( )。
知情权是指公民有权知道他应该知道的事情,国家应该最大限度地确认和保障公民知悉、获取信息的权利,尤其是政务信息的权利。根据上述定义,下面与知情权无关的是()。
在考生文件夹下存在一个数据库文件“samp2.accdb”,里面已经设计好三个关联表对象“tStud”“tCourse”和“tScore”,以及表对象“tTemp”。试按以下要求完成设计。创建一个查询,查找5号入校的学生,显示其“学号”“姓名”“性别”
A、Shegetsillatthesametimeeveryyear.B、Shedoesn’tgetenoughexercise.C、Sheoftenhasdifficultysleeping.D、She’ssick
最新回复
(
0
)