科學(xué)六十秒英文原文

1、11-23 solar road ways take baby stepsthe path to solar roadways is said to be paved with good intentions. but actually it's going to be paved with modular, concrete-reinfoced photovoltaic panels protected by tempered glassat least that's the vision that idaho-based solar roadways has had for

2、 the past few years. so far they've man aged to build an 11-metellong solar parki ng lot next to the company's lab.mea nwhile, the dutch are taki ng a slightly d iff ere nt app roach this week a tow n in the northern suburbs of amsterdam officially opened a 70-meter stretch of bike path they

3、 claim is the world's first road to con vert sunlight into electricity. they plan to add at least another 25 meters to the solaroad project in the next two years.they're testi ng the bike path for two thin gs, moinly. can it gen erate eno ugh juice to power street lighting, traffic systems,

4、electric cars and households? and will it hold up to the daily wear and tear of cyclists, joggers and baby strollers, not to mention extreme weather and falling objects?if solaroad proves successful in both areas, the dutch hope to extend the project to turn entire thoroughfares into massive solar p

5、anels. designed by, ya know, road scholars.11-24 worse than the bitecity dwellers across the u.s. might agree on one comm on en emy: bedbugs. but hey, not to worry, right? "bedbugs are not known to spread diseases, but bites can be very itchy and irritating.n or so says the new york city depart

6、ment of health. but that assertion may not be true because a new study suggests bedbugs could be capable of spreading infectionspecifically, by passing on the parasite that causes chagas disease.chagas con cause anything from mild headaches to eventual heart failure. the condition is usually spread

7、by what's called the kissing bug a relative of bedbugs, which also feeds on blood. but it doesn*t pass the parasite through its saliva, as happens with malaria, for example.hyou get it when the bug bites you and then defecates on you. the parasite is in the feces of the bug." michael levy,

8、a disease ecologist at the university of pennsylvania levy says scratching the bite then works the parasite into the skin, infecting the victim.levy and his colleagues wanted to see if the same thing could happen with bedbugs. so they let em loose on mice that carried the tripa no soma cruzi parasit

9、e. the bugs caught itand were then able to transmit the parasite back to mice. with one caveat - some mice actually hunted and ate the bugs - a sure route for infection. "people don't eat bedbugs, so we're not really at risk of being infected thro ugh the oral route by bedbugs/1 that sa

10、id, one mouse actually did catch the disease not by snacking, but through a bedbug bitemore analogous to the way a human might the study is in the american journal of tropical medicine and hygienerenzo salazar et al.: bed bugs (cimex lectularius) as vectors of trypa no soma cruziany advice for the b

11、edbug-phobic? “don't panic. it's important to remember that bedbugs may be able to carry the disease, but they don't cause it.1' meaning，you'd n eed to live with some one with chagas disease, who can pass the parasite to a bedbug, and then actually catch it from that bug still, l

12、evy says, bugs pave the way for pathogens to spread. nit,s very dangerous to let bugs that feed on human blood get out ofc on trol, like unfortun ately has happe ned in the un ited states and across the world with bedbugs.n maybe its time to treat bedbugs like a public health issue, levy says, rathe

13、r than just a pest.11-27 better barley let people settle tibetan pleteauthe tibetan plateau, at an altitude of some 3,000 meters above sea level, is often called the "roof of the world." some prehistoric people tried living there starting about 20,000 years ago. remains of cooked animals a

14、nd small-scale hearths show that a few hardy souls did give the harsh region a go, at least temp or arily. but they did not stick aroundpermanent human settlements in the area began about 5,200 years ago. so scie ntists wan ted to know. what changed?researchers collected artifacts, animal bones and

15、plant remains from 53 sites the oldest camps only reached altitudes of about 2,500 meters and at these sites, millet makes up 98 percent of dietary grainbut about 3,600 years a new kind of barley arrived in the region, after being domesticated in the fertile crescent that spread from the persian gul

16、f to the nile. the new barley tolerated frost and had a ion ger growing season. which means it grew above the 3000 meter marka nd that people could settle there. diets at those heights became dominated by the new, hardy barley.the fin dings are in the jour nal scie nee. f. h. che n et al, agricultur

17、e facilitated permanent human occupation of the tibetan plateau after 3600 bpthe researchers say that the cross-cultural grain exchange from the fertilecresce nt thus appears to be what allowed huma ns to fin ally reach the roof of the world.11-28 looking back on 40 years for lucyforty years ago yes

18、terday, november 24, 1974, paleoanthropologist donald johanson found in ethiopia what's arguably the most famous and important fossil of a huma n ancestor: lucy. last mon th, at the scie ncew riters2014 meeting in columbus, ohio, johans on talked about the moment he laid eyes on lucy."on th

19、at eventful day in 1974 i was out, with a graduate student, tom gray, and we were walking back to our land rover to go back to camp to enjoy a swim in the river with the crocodiles and enjoy a nice little lunch. and i am always looking at the ground. i find more quarters by parki ng meters tha n any

20、 body i know, i think. and you know how it is you find what you're looking for, right?z/because a year before the discovery a geologist had left his footprints four-to-five feet away from the skeleton, because he was looking for rocks. i was looking for bones. and i found a little piece of elbow

21、, that little hinge that allows us to 什ex and extend our arm. and i knew from my studies of osteology, of comparative an atomy and so or that this had to be from a huma n ancestor."and i as looked up the slope, i saw other fragments eroding out. and we recovered over a two-week-long excavation operation roughly, not coun