Theory, though, does not always translate into practice, and just as governments have committed themselves to the greater use of biofuels, questions are being raised about how green this form. of energy really is. The latest comes from the International Council for Science (ICSU) based in Paris.
The ICSU report concludes that, so far, the production of biofuels has aggravated rather than ameliorated global warming. In particular, it supports some controversial findings published in 2007 by Paul Crutzen of the Max Planck Institute for Chemistry in Germany. Dr. Crutzen concluded that most analyses had underestimated the importance to global warming of a gas called nitrous oxide (N2nO). The amount of this gas released by farming biofuel crops such as maize and rape probably negates by itself any advantage offered by reduced emissions of CO2n.
Although N2nO is not common in the Earth’s atmosphere, it is a more potent greenhouse gas than CO2n and it hangs around longer. The result is that, over the course of a century, its ability to warm the planet is almost 300 times that of an equivalent mass of CO2n.
N2nO is made by bacteria that live in soil and water and, these days, their raw material is often the nitrogen-rich fertiliser that modern farming requires. Since the 1960s the amount of fertiliser used by farmers has increased sixfold, and not all of that extra nitrogen ends up in their crops. Maize, in particular, is described by experts in the field as a “nitrogen-leaky” plant because it has shallow roots and takes up nitrogen for only a few months of the year. This would make maize (which is one of the main sources of biofuel) a particularly bad contributor to global N2nO emissions.
But it is not just biofuels that are to blame. The ICSU report suggests N2nO emissions in general are probably more important than had been realised. Previous studies, including those by the International Panel on Climate Change (IPCC), a United Nations-appointed body of experts, may have miscalculated their significance — and according to Adrian Williams of Cranfield University, in Britain, even the IPCC’s approach suggests that the global-warming potential of most of Britain’s annual crops is dominated by N2nO emissions.
Biofuels are appreciated by governments because
A.burning biofuels does not add CO2n to the atmosphere.
B.biofuels can slow down the pace of global warming.
C.biofuels is a promising and profitable form. of green energy.
D.burning biofuels discharges less N2nO than burning oils.
第1题
患者男性,55岁,1周前心前区剧烈疼痛,随后心悸、气促,当时未就诊,现疑诊急性心肌梗死。
为确诊,目前最有帮助的酶学检查是
A.CK同工酶
B.AST
C.CK
D.ALT
E.LD
第2题
(题干) 患者男性,55岁,1周前心前区剧烈疼痛,随后心悸、气促,当时未就诊,现疑诊急性心肌梗死。 为确诊,目前最有帮助的酶学检查是A.CK同工酶
B.AST
C.CK
D.ALT
E.LD
急性心肌梗死时,最先恢复正常的心肌酶是A.ALT
B.LD
C.AST
D.α-HBDH
E.CK
第3题
(题干) 患者男性,55岁,1周前心前区剧烈疼痛,随后心悸、气促,当时未就诊,现疑诊急性心肌梗死。 为确诊,目前最有帮助的酶学检查是A.CK同工酶
B.AST
C.CK
D.ALT
E.LD
急性心肌梗死时,最先恢复正常的心肌酶是A.ALT
B.LD
C.AST
D.α-HBDH
E.CK
请帮忙给出每个问题的正确答案和分析,谢谢!
第4题
(108-110题共用题干)
患者,男,55岁。因心悸伴消瘦1周来诊。查体:脉率84次/分,血压148/60mmHg,甲状腺弥漫性Ⅱ度肿大,可闻及血管杂音,肺(-);心率112次/分。心律绝对不整,心音强弱不等,腹(-)
该患者的心律失常类型是
A.心房颤动
B.心房扑动
C.频发早搏
D.二度Ⅱ型房室传导阻滞
第5题
A.ALT
B.LD
C.AST
D.α-HBDH
E.CK
第6题
A.ALT
B. LD
C. AST
D. α-HBDH
E. CK
第7题
A.ALT
B.LD
C.AST
D.-HBDH
E.CK
第8题
男,64岁,8年前体检时发现血压为l60/90mmHg,近l年来心前区不适,心悸,逐渐加重。查体:BP:21.3/10kPa(160/70mmHg),心浊音界增大呈靴形。该患者心脏呈靴形增大说明()。
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!