Detection of sea-serpent field lines in sunspot penumbrae

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2009年考研英语冲刺阅读理解专项训练047

Overfishing of one of the ocean’ s top predators has triggered a lethal chain reaction that threatens to decimate populations of bay scallops, oysters, and clams, warns a new study, e Plunging populations of11 large shark species have caused a spike in the numbers of their prey, including smaller sharks, rays and skates．These creatures in turn are wiping out other marine organisms and may be destroying sea grass habitat, which serves as a nursery for many species． Sharks have had a rough few decades．Demand for their fins and meat has resulted in increasin exploitation, and the creatures are often accidentally captured by swordfish and tuna fishers, As man as 73 million sharks are killed annually, and past studies have indicated many populations have been ct by half．Nonetheless, scientists have had difficulty gauging the decline in several shark species over the years because of a lack of data．The effect of this decline on ocean ecosystems has also proven hard t measure． To get a better grip on the problem’, marine biologist Julia Baum of Dalhousie University in Halifax Canada, and colleagues trawled 35 years of marine surveys and fisheries data to document declines i large sharks off the eastern seaboard of the U．S．The numbers, reported today in Science, are stark The blacktip shark population has plummeted 93% since 1972, with similar declines for tiger, bull, an smooth hammerhead sharks． Simultaneously, the abundance of 12 of the 14 species that these sharks prey on--including the litt] skate, the chain catshark, and the cownose ray--increased dramatically．The latter has seen its numbers swell ten-fold．The jump in ray numbers is especially troubling, notes co-author and marine biologist Charles Peterson of the University of North Carolina at Chapel Hill, because the fish shred the sea grass that houses crabs and clams．In fact, he notes, by 2004 ray predation had shut down Nort Carolina’s century-old bay scallop fishery． The 11 other shark prey species whose populations rose over the 35-year period could be havin similar impacts to that of the cownose ray, says Baum． The result is profound because the high diversity of fishes in the northwest Atlantic has bee thought to minimize catastrophic changes in the food web, says marine scientist Kenneth Frank of the Bedford Institute of Oceanography in Dartmouth, Canada．Sharks are only part of the puzzle, however Frank warns．People’s appetites for oysters, clams, and scallops are likely having a more direct impact on these populations, he says．[414 words] 1．The overfishing of sharks may result in______ A．the abundance of sea grass habitat B．the ruin of nursery for many marine species C．the obvious increase of most marine species D．the huge decline of the populations of their prey 2．What contributes most to the overfishing of sharks is______ A．the sharks accidentally captured by tuna fishers B．the rough few decades that sharks have suffered C．the ever-increasing demand for their fins and meat D．the millions of sharks killed deliberately each year 3．Julia Baum studied marine surveys and fisheries data in order to______ A．prove the fact that shark populations have fallen sharply B．cast light on the effect of shark decline on ocean ecosystrems C．document the shark species which have declined most rapidly D．understand the subtle relationship between predators and prey 4．The rapid increase of the cownose ray results from______ A．the ten-fold increase of its numbers in a short time B．the abundance of the 12 species that sharks prey on C．the tremendous decline of the number of its predators D．the decline of sharks off the eastern seaboard of America 5．The populations of bay scallops, oysters, and clams are threatened directly by______.examda. A．the high diversity of fishes in the northwest Atlantic B．the catastrophic changes in the food web in the Atlantic C．the lethal reaction triggered by the overfishing of sharks D．the strong desire of many people for them as their delicious food难句透析 ①Overfishing of one of the ocean’S top predators has triggered a lethal chain reaction Ethat threatens to decimate populations of bay scallops，oysters，and clams]，warns a new study．【结构】“warns a new study”是本句的主句。

2017年全国硕士研究生招生考试英语一试题和答案

2017年全国硕士研究生招生考试英语一试题Section I Use of EnglishDirections:Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. (10 points)Could a hug a day keep the doctor away? The answermay be a resounding "yes!" ___1__ helping you feel close and __2___to people you care about, it turns out that hugs can bring a ___3__ of healthbenefits to your body and mind. Believe it or not, a warm embrace might evenhelp you __4___ getting sick this winter.In a recent study ___5__ over 400 healthy adults,researchers from Carnegie Mellon University inPennsylvania examined the effects of perceived social support and the receiptof hugs ___6__ the participants' susceptibility to developing the common coldafter being ___7__ to the virus. People who perceived greater social supportwere less likely to come ___8__ with a cold, and the researchers __9___ thatthe stress-reducing effects of hugging ___10__ about 32 percent of thatbeneficial effect. ___11__ among those who got a cold, theones who felt greater social support and received more frequent hugs hadless severe __12___."Hugging protects people who are under stress fromthe ___13__ risk for colds that's usually __14___ with stress," notesSheldon Cohen, a professor of psychology at Carnegie. Hugging "is a markerof intimacy and helps __15___ the feeling that others are there to help ___16__difficulty."Some experts ___17__ the stress-reducing,health-related benefits of hugging to the release of oxytocin, often called"the bonding hormone" __18___ it promotes attachment inrelationships, including that between mothersand their newborn babies. Oxytocin is made primarily in the central lower partof the brain, and some of it is released into the bloodstream. But some of it___19__ in the brain, where it __20___ mood, behavior and physiology.1. [A]Besides [B]Unlike [C]Throughout [D]Despite2. [A]equal [B]restricted [C]connected [D]inferior3. [A]view [B]host [C]lesson [D]choice4. [A]avoid [B]forget [C]recall [D]keep5.[A]collecting [B]affecting [C]guiding [D]involving6. [A]on [B]in [C]at [D]of7.[A]devoted [B]attracted [C]lost [D]expose d8. [A]along [B]across [C]down [D]out9.[A]imagined [B]denied [C]doubted [D]calculate d10.[A]served [B]restored [C]explained [D]required11. [A]Thus [B]Still [C]Rathe [D]Even12. [A]defeats [B]symptoms [C]errors [D]tests13.[A]highlighted [B]increased [C]controlled [D]minimized14. [A]presented [B]equipped [C]associated [D]compa red15.[A]assess [B]generate [C]moderate [D]record16. [A]in the name of [B] in the form of [C] in the face of [D] in the way of17. [A]attribute [B]commit [C]transfer [D]return18. [A]unless [B]because [C]though [D]until19.[A]remains [B]emerges [C]vanishes [D]decreases20.[A]experiences [B]combines [C]justifies [D]influencesSection II Reading ComprehensionPart ADirections:Read the following four texts. Answer the questions below each text by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. (40 points)Text 1First two hours, now three hours — this is how far in advance authorities are recommending people show up to catch a domestic flight, at least at some major U.S. airports with increasingly massive security lines.Americans are willing to tolerate time-consuming security protocols in return for increased safety. The crash of EgyptAir Flight 804, which terrorists may have downed over the Mediterranean Sea, provides another tragic reminder of why. But demanding too much of air travelers or providing too little security in return undermines public support for the process. And it should: Wasted time is a drag on Americans' economic and private lives, not to mention infuriating.Last year, the Transportation Security Administration(TSA) found in a secret check that undercover investigators were able to sneak weapons — both fake and real — past airport security nearly every time they tried. Enhanced security measures since then, combined with a rise in airline travel due to the improving economy and low oil prices, have resulted in long waits at major airports such as Chicago's O'Hare International. It is not yet clear how much more effective airline security has become — but the lines are obvious.Part of the issue is that the government did not anticipate the steep increase in airline travel, so the TSA is now rushing to get new screeners on the line. Part of the issue is that airports have only so much room for screening lanes. Another factor may be thatmore people are trying to overpack their carry-on bags to avoid checked-baggage fees, though the airlines strongly dispute this.There is one step the TSA could take that would not require remodeling airports or rushing to hire: Enroll more people in the PreCheck program. PreCheck is supposed to be a win-win for travelers and the TSA. Passengers who pass a background check are eligible to use expedited screening lanes. This allows the TSA to focus on travelers who are higher risk, saving time for everyone involved. TSA wants to enroll 25 million people in PreCheck.It has not gotten anywhere close to that, and one big reason is sticker shock: Passengers must pay $85 every five years to process their background checks. Since the beginning, this price tag has been PreCheck's fatal flaw. Upcoming reforms might bring the price to a more reasonable level. But Congress should look into doing so directly, by helping to finance PreCheck enrollment or to cut costs in other ways.The TSA cannot continue diverting resources into underused PreCheck lanes while most of the traveling public suffers in unnecessary lines. It is long past time to make the program work.21. The crash of EgyptAir Flight 804 is mentioned to____________.[A] explain American’s tolerance of current security checks.[B] stress the urgency to strengthen security worldwide.[C] highlight the necessity of upgrading major U.S. airports.[D] emphasize the importance of privacy protection.22. Which of the following contributes to long waits at major airports?[A] New restrictions on carry-on bags.[B] The declining efficiency of the TSA.[C] An increase in the number of travellers.[D] Frequent unexpected secret checks.23. The word “expedited” (Liner 4, Para. 5) is closet in meaning to____________.[A] quieter.[B] cheaper.[C] wider.[D] faster.24. One problem with the PreCheck program is____________.[A] a dramatic reduction of its scale.[B] its wrongly-directed implementation.[C] the government’s reluctance to back it.[D] an unreasonable price for enrollment.25. Which of the following would be the best for the text?[A] Less Screening for More Safety[B] PreCheck – a Belated Solution[C] Getting Stuck in Security Lines[D] Underused PreCheck LanesText 2“The ancient Hawaiians were astronomers,” wrote Queen Liliuokalani, Hawaii's last reigning monarch, in 1897. Star watchers were among the most esteemed members of Hawaiian society. Sadly, all is not well with astronomy in Hawaii today. Protests have erupted over construction of the Thirty Meter Telescope (TMT), a giant observatory that promises to revolutionize humanity's view of the cosmos.At issue is the TMT's planned location on Mauna Kea, a dormant volcano worshiped by some Hawaiians as the piko, that connects the Hawaiian Islands to the heavens. But Mauna Kea is also home to some of the world's most powerful telescopes. Rested in the Pacific Ocean, Mauna Kea's peak rises above the bulk of our planet's dense atmosphere, where conditions allow telescopes to obtain images of unsurpassed clarity.Opposition to telescopes on Mauna Kea is nothing new. A small but vocal group of Hawaiians and environmentalists have long viewed their presence as disrespect far sacred land and a painful reminder of the occupation of what was once a sovereign nation.Some blame for the current controversy belongs to astronomers. In their eagerness to build bigger telescopes, they forgot that science is not the only way of understanding the world. They did not always prioritize the protection of Mauna Kea's fragile ecosystems or its holiness to the islands' inhabitants. Hawaiian culture is not a relic of the past；it is a living culture undergoing a renaissance today.Yet science has a cultural history, too, with roots going back to the dawn of civilization. The same curiosity to find what lies beyond the horizon that first brought early Polynesians to Hawaii's shores inspires astronomers today to explore the heavens.Calls to disassemble all telescopes on Mauna Kea or to ban future development there ignore the reality that astronomy and Hawaiian culture both seek to answer big questions about who we are, where we come from and where we are going. Perhaps that is why we explore the starry skies, as if answering a primal calling to know ourselves and our true ancestral homes.The astronomy community is making compromises to change its use of Mauna Kea. The TMT site was chosen to minimize the telescope’s visibility around the island and to avoid archaeological and environmental impact. To limit the number of telescopes on Mauna Kea, old ones will be removed at the end of their lifetimes and their sites returned to a natural state. There is no reason why everyone cannot be welcomed on Mauna Kea to embrace their cultural heritage and to study the stars.26. Queen Liliuokalani’s remark in Paragraph 1 indicates____________.[A] her conservative view on the historical role of astronomy.[B] the importance of astronomy in ancient Hawaiian society.[C]the regrettable decline of astronomy in ancient times.[D] her appreciation of star watchers’ feats in her time.27. Mauna Kea is deemed as an ideal astronomical site due to____________.[A] its geographical features.[B] its protective surroundings.[C] its religious implications.[D] its existing infrastructure.28. The construction of the TMT is opposed by some locals partlybecause____________.[A] it may risk ruining their intellectual life.[B] it reminds them of a humiliating history.[C] their culture will lose a chance of revival.[D] they fear losing control of Mauna Kea.29. It can be inferred from Paragraph 5 that progress in today’sastronomy____________.[A] is fulfilling the dreams of ancient Hawaiians.[B] helps spread Hawaiian culture across the world.[C] may uncover the origin of Hawaiian culture.[D] will eventually soften Hawaiians’ hostility.30. The author’s attitude toward choosing Mauna Kea as the TMT site is oneof____________.[A] severe criticism.[B] passive acceptance.[C] slight hesitancy.[D] full approval.Text 3Robert F. Kennedy once said that a country's GDP measures “everything except that which makes life worthwhile.” With Britain voting to leave the European Union, and GDPalready predicted to slow as a result, it is now a timely moment to assess what he was referring to.The question of GDP and its usefulness has annoyed policymakers for over half a century. Many argue that it is a flawed concept. It measures things that do not matter and misses things that do. By most recent measures, the UK’s GDP has been the envy of the Western world, with record low unemployment and high growth figures. If everything was going so well, then why did over 17 million people vote for Brexit, despite the warnings about what it could do to their country’s economic prospects?A recent annual study of countries and their ability to convert growth intowell-being sheds some light on that question. Across the 163 countries measured, the UK is one of the poorest performers in ensuring that economic growth is translated into meaningful improvements for its citizens. Rather than just focusing on GDP, over 40 different sets of criteria from health, education and civil society engagement have been measured to get a more rounded assessment of how countries are performing.While all of these countries face their own challenges, there are a number of consistent themes. Yes, there has been a budding economic recovery since the 2008 global crash, but in key indicators in areas such as health and education, major economies have continued to decline. Yet this isn’t the case with all countries. Some relatively poor European countries have seen huge improvements across measures including civil society, income equality and environment.This is a lesson that rich countries can learn: When GDP is no longer regarded as the sole measure of a country’s success, the world looks very different.So what Kennedy was referring to was that while GDP has been the most common method for measuring the economic activity of nations, as a measure, it is no longer enough. It does not include important factors such as environmental quality or education outcomes – all things that contribute to a person's sense of well-being.The sharp hit to growth predicted around the world and in the UK could lead to a decline in the everyday services we depend on for our well-being and for growth. But policymakers who refocus efforts on improving well-being rather than simply worrying about GDP figures could avoid the forecasted doom and may even see progress.31. Robert F. Kennedy is cited because he____________.[A]praised the UK for its GDP.[B]identified GDP with happiness.[C]misinterpreted the role of GDP.[D]had a low opinion of GDP.32. It can be inferred from Paragraph 2 that____________.[A]the UK is reluctant to remold its economic pattern.[B]the UK will contribute less to the world economy.[C]GDP as the measure of success is widely defied in the UK.[D]policymakers in the UK are paying less attention to GDP.33. Which of the following is true about the recent annual study?[A]It excludes GDP as an indicator.[B]It is sponsored by 163 countries.[C]Its criteria are questionable.[D]Its results are enlightening.34. In the last two paragraphs, the author suggests that____________.[A]the UK is preparing for an economic boom.[B]high GDP foreshadows an economic decline.[C]it is essential to consider factors beyond GDP.[D]it requires caution to handle economic issues.35. Which of the following is the best for the text?[A]High GDP But Inadequate Well-being, a UK lesson[B]GDP figures, a Window on Global Economic Health[C] Robert F. Kennedy, a Terminator of GDP[D]Brexit, the UK’s Gateway to Well-beingText 4In a rare unanimous ruling, the US Supreme Court has overturned the corruption conviction of a former Virginia governor, Robert McDonnell. But it did so while holding its nose at the ethics of his conduct, which included accepting gifts such as a Rolex watch and a Ferrari Automobile from a company seeking access to government.The high court’s decision said the judge in Mr. McDonnell’s trail failed to tell a jury that it must look only at his “official acts,” or the former governor’s decisions on “specific” and “unsettled” issues related to his dut ies.Merely helping a gift-giver gain access to other officials, unless done with clear intent to pressure those officials, is not corruption, the justices found.The court did suggest that accepting favors in return for opening doors is “distasteful” and “nasty.” But under anti-bribery laws, proof must be made of concrete benefits, such as approval of a contract or regulation. Simply arranging a meeting, making a phone call, or hosting an event is not an “official act.”The court’s ruling is legally sound in defining a kind of favoritism that is not criminal. Elected leaders must be allowed to help supporters deal with bureaucratic problems without fear of prosecution of bribery. “The basic compact underlying representative government,” wrote Chief Justice John Roberts for the court, “assumes that public officials will hear from their constituents and act on their concerns.”But the ruling reinforces the need for citizens and their elected representatives, not the courts, to ensure equality of access to government. Officials must not be allowed to play favorites in providing information or in arranging meetings simply because an individual or group provides a campaign donation or a personal gift. This type of integrity requires will-enforced laws in government transparency, such as records of official meetings, rules on lobbying, and information about each elected leader’s source of wealth.Favoritism in official access can fan public perceptions of corruption. But it is not always corruption. Rather officials must avoid double standards, or different types of access for average people and the wealthy. If connections can be bought, a basic premise of democratic society – that all are equal in treatment by government- is undermined. Good government rests on an understanding of the inherent worth of each individual.The court’s ruling is a step forward in the struggle against both corruption and official favoritism.36. The underlined sentence(Para.1) most probably shows that the court____________.[A] avoided def ining the extent of McDonnell’s duties.[B] made no compromise in convicting McDonnell.[C] was contemptuous of McDonnell’s conduct.[D] refused to comment on McDonnell’s ethics.37. According to Paragraph 4, an official act is deemed corruptive only if it involves____________.[A] concrete returns for gift-givers.[B] sizable gains in the form of gifts.[C] leaking secrets intentionally.[D] breaking contracts officially.38. The court’s ruling is d on the assumption that public officials are____________.[A] allowed to focus on the concerns of their supporters.[B] qualified to deal independently with bureaucratic issues.[C] justified in addressing the needs of their constituents.[D] exempt from conviction on the charge of favoritism.39. Well-enforced laws in government transparency are needed to____________.[A] awaken the conscience of officials.[B] guarantee fair play in official access.[C] allow for certain kinds of lobbying.[D] inspire hopes in average people.40. The author’s attitude toward the court’s ruling is____________.[A] sarcastic.[B] tolerant.[C] skeptical.[D] supportive.Part BDirections:The following paragraphs are given in a wrong order. For Questions 41-45, you are required to reorganize these paragraphs into a coherent article by choosing from the list A-G to filling them into the numbered box. Paragraphs B and D have been correctly placed. Mark your answers on ANSWER SHEET. (10 points)[A]The first published sketch, “A Dinner at Poplar Walk” brought tears to Dickens’s eyes when he discovered it in the pages of The Monthly Magazine. From then on his sketches ,which appeared under th e pen name “Boz” in The Evening Chronicle, earned him a modest reputation.[B]The runaway success of The Pickwick Papers, as it is generally known today, secured Dickens’s fame. There were Pickwick coats and Pickwick cigars, and the plump, spectacled hero, Samuel Pickwick, became a national figure.[C]Soon after Sketches by Boz appeared, a publishing firm approached Dickens to write a story in monthly installments, as a backdrop for a series of woodcuts by the ten-famous artist Robert Seymour, who had originated the idea for the story. With characteristic confidence, Dickens successfully insisted that Seymour’s pictures illustrate his own story instead. After the first installment, Dickens wrote to the artist and asked him to correct a drawing Dickens felt was not faithful enough to his prose. Seymour made the change, went into his backyard, and expressed his displeasure by committing suicide. Dickens and his publishers simply pressed on with a new artist. The comic novel, The Posthumous Papers of the Pickwick Club, appeared serially in 1836 and 1837, and was first published in book form in 1837.[D]Charles Dickens is probably the best-known and, to many people, the greatest English novelist of the 19th century. A moralist, satirist, and social reformer. Dickens crafted complex plots and striking characters that capture the panorama of English society.[E]Soon after his father’s release from prison, Dickens got a better job as errand boy in law offices. He taught himself shorthand to get an even better job later as a court stenographer and as a reporter in Parliament. At the same time, Dickens, who had a reporter’s eye for transcribing the li fe around him especially anything comic or odd, submitted short sketches to obscure magazines.[F] Dickens was b orn in Portsmouth, on England’s southern coast. His father was a clerk in the British navy pay office –a respectable position, but wish little social status. His paternal grandparents, a steward and a housekeeper possessed even less status, havingbeen ser vants, and Dickens later concealed their background. Dicken’s mother supposedly came from a more respectable family. Yet two years before Dick en’s birth, his mother’s father was caught stealing and fled to Europe, never to return. The family’s increasing p overty forced Dickens out of school at age 12 to work in Warren’s Blacking Warehouse, a shoe-polish factory, where the other working boys mock ed him as “the young gentleman.” His father was then imprisoned for debt. The humiliations of his father’s imprisonment and his labor in the blacking factory formed Dicken’s greatest wound and became his deepest secret. He could not confide them even to his wife, although they provide the unacknowledged foundation of his fiction.[G] After Pickwick, Dickens plunged into a bleaker world. In Oliver Twist, e traces an orphan’s progress from the workhouse to the criminal slums of London. Nicholas Nickleby, his next novel, combines the darkness of Oliver Twist with the sunlight of Pickwick. The popularity of these novels consolidated Dichens’ as a nationally and internationally celebrated man of letters.D → 41.→ 42.→ 43.→ 44.→ B →45.Part CDirections:Read the following text carefully and then translate the underlined segments into Chinese. Your translation should be written neatly on the ANSWER SHEET. (10 points)The growth of the use of English as the world`s primary language for international communication has obviously been continuing for several decades.(46)But even as the number of English speakers expands further there are signs that the global predominance of the language may fade within the foreseeable future.Complex international, economic, technological and culture change could start to diminish the leading position of English as the language of the world market, and UK interests which enjoy advantage from the breath of English usage would consequently face new pressures. Those realistic possibilities are highlighted in the study presented by David Graddol(47)His analysis should therefore end any self-contentedness among those who may believe that the global position of English is so stable that the young generation of the United Kingdom do not need additional language capabilities.David Graddol concludes that monoglot English graduates face a bleak economic future as qualified multilingual youngsters from other countries are proving to have a competitive advantage over their British counterparts in global companies and organizations. Alongside that,(48)many countries are introducing English into the primary-school curriculum but British schoolchildren and students do not appear to be gaining greater encouragement to achieve fluency in other languages.If left to themselves, such trends will diminish the relative strength of the English language in international education markets as the demand for educational resources in languages, such as Spanish ,Arabic or Mandarin grows and international business process outsourcing in other language such as Japanese, French and German, spreads.(49)The changes identified by David Graddol all present clear and major challenges to UK`s providers of English language teaching to people of other countries and to broader education business sectors. The English language teaching sector directly earns nearly &1.3 billion for the UK in invisible exports and our other education related explores earn up to &10 billion a year more. As the international education market expands, the recent slowdown in the number of international students studying in the main English-speaking countries is likely to continue, especially if there are no effective strategic policies to prevent such slippage.The anticipation of possible shifts in demand provided by this study is significant:(50) It gives a basis to all organization which seek to promote the learning and very different operating environment. That is a necessary and practical approach. In this as in much else, those who wish to influence the future must prepare for it.Section IV WritingPart A51. Directions:You are to write an email to James Cook, a newly-arrived Australia professor, recommending some tourist attraction in your city .Please give reason for your recommendation.You should write nearly on the answer/sheet.Dot not sign your own name at the end of the email .use "Li Ming"insteadDo not write the address.(10 points) (10 points)Part B52. Directions:Write an essay of 160-200 words based on the following drawing. In your essay, you should1) describe the drawing briefly2) explain its intended meaning, and3) give your commentsYou should write neatly on ANSWER SHEET. (20 points)答案：完形填空：1-5 ACBAD 6-10 ADCDC 11-15 DBBCB 16-20 CABAD阅读：21-25 ADADC 26-30 ABBAD 31-35 DCDCA 36-40 CACBD新题型：41-45 FEACG翻译：【参考译文】(46) 但是即使当下英语使用者的人群还在进一步扩大，有迹象表明：在可预见的未来，英语可能会逐渐失去其全球主导地位。

托福阅读之生命科学篇：海洋微生物

托福阅读之生命科学篇:海洋微生物阅读前，先来学习一下文章中的疑难词：Aerobicadj. 需氧的Sedimentn. 沉积；沉淀物penetration n. 渗透；突破；侵入；洞察力respiration n. 呼吸；呼吸作用Extrapolate v. 外推；推断Subduction n.减去oxidized adj. 被氧化的v. 氧化一起开始阅读吧！Presence of oxygen and aerobic communities from sea floor to basement in deep-sea sediments氧气和需氧生物在海底层到海底沉积物下的存在The depth of oxygen penetration into marine sediments differs considerably from one region to another.氧气在海底沉积物中的渗透深度在不同的区域大有不同。

In areas with high rates of microbial respiration, O2 penetrates only millimetres to centimetres into the sediments, but active anaerobic microbial communities are present in sediments hundreds of metres or more below the sea floor. In areas with low sedimentary respiration, O2 penetrates much deeper, but the depth to which microbial communities persist was previously unknown.在那些微生物呼吸活跃的区域，氧气的渗透深度只有毫米到厘米的量值，但是活跃的厌氧微生物群存在于海底沉积物几百米深或者海底更深的地方。

浙江省稽阳联谊学校2023-2024学年高三上学期11月联考英语试题

12.What does the man suggest the woman do?
A.Borrow the notes.B.Meet Prof. Garcia.C.Watch the video playback.
13.What does the woman want to do?
A.Study the lecture in depth.B.Buy something to drink.C.Build a website.
例: How much is the shirt?
A.₤ 19.15. B.£ 9.18. C.£ 9.15.
答案是C。
1.【此处可播放相关音频，请去附件查看】
Which place are the speakers going to first?
A.To a hotel.B.To a restaurant.C.To the office.
M: Oh, I will. But it is a little small for me. Can you show me a bigger one?
W: Of course. Just a second.
听下面一段较长对话，回答以下小题。【此处可播放相关音频，请去附件查看】
10.What did the woman do yesterday?
A.In 15 minutes.B.In 30 minutes.C.In 45 minutes.
【答案】6. A 7. C
【解析】
【原文】W: Hello. Dick. Where are you going?
M: I’m going to the stadium.
W: What are you going there for?

FDA水解酶分析法表征近海泥滩微生物活性

第34卷第10期2013年10月环境科学ENVIRONMENTAL SCIENCEVol．34，No．10Oct．，2013FDA 水解酶分析法表征近海泥滩微生物活性刘叶1，邹立1，2，刘陆1，高冬梅1，2*（1.中国海洋大学环境科学与工程学院，青岛266100；2.中国海洋大学海洋环境与生态教育部重点实验室，青岛266100）摘要：针对近海潮间带环境高盐、有机质组成复杂和微生物活性低的特点，根据微生物酶解荧光素双醋酸酯（FDA ）产生荧光素的原理，建立了适于泥滩类潮间带沉积环境中微生物活性检测的荧光光度法．从样品浸提液、反应产物检测仪器、预处理方法、实验条件等不同方面进行优化，确定泥滩类潮间带沉积环境中微生物活性的最优检测方法和条件如下：沉积物湿样以灭菌陈海水为介质，加入吐温-80分散剂，充分振荡后静置，使较大颗粒自然沉降；取上层悬浊液，经无菌滤膜（1.2μm ，多次煮沸灭菌）过滤，得到待测菌液；取待测菌液加入适量FDA 溶液，在25 30ħ下避光反应180min ，以丙酮为终止剂终止反应，25min 内以分子荧光光度计（激发波长488nm ，发射波长530nm ）测定反应产物的荧光强度，该方法的检测范围（以干重计）是3.0ˑ103 1.1ˑ105个·g －1．微生物活性以单位质量样品的荧光素含量表示（μg ·g －1，干重）．关键词：海洋泥滩沉积物；微生物活性；FDA 水解酶分析；荧光光度法中图分类号：X830.2文献标识码：A文章编号：0250-3301（2013）10-3818-07收稿日期：2013-01-19；修订日期：2013-04-26基金项目：国家自然科学基金项目（41176064）作者简介：刘叶（1988 ），女，硕士研究生，主要研究方向为海洋生物地球化学，E-mail ：liuye@ouc．edu．cn *通讯联系人，E-mail ：gdm@ouc．edu．cn Characterization of Microbial Activities in Marine Mudflat Sediment Using FDAHydrolase AnalysisLIU Ye 1，ZOU Li 1，2，LIU Lu 1，GAO Dong-mei 1，2（1.College of Environmental Science and Engineering ，Ocean University of China ，Qingdao 266100，China ； 2.Key Laboratory of Marine Environment ＆Ecology Ministry of Education ，Ocean University of China ，Qingdao 266100，China ）Abstract ：A method based on fluorescence spectrometry was developed to detect the microbial activities in marine mudflat sediment ，where is characterized by high salinity ，complex organic compounds and low microbial biomass．This paper optimized the sample extracts ，the detection equipment for reaction products ，the pretreatment methods ，and the experimental conditions．The optimal procedure is described as following．Fresh sediment was first extracted with sterilized and aged seawater ，followed by the addition of Tween-80solution ，then uniformly dispersed by thorough oscillating ，and kept steady for precipitation．After filtration through a sterilized membrane （1.2μm ，sterilized in boiling water repeatedly ），the supernatant was supplemented with an appropriate amount of FDA solution and allowed to react in dark for 180min at temperature ranged 25-30ħ．The reaction was terminated by the addition of acetone ，and the fluorescence intensity of the reaction mixture was measured within 25min using a molecular fluorescence photometer at an excitation wavelength of 488nm and an emission wavelength of 530nm ，and the detection range of this method （dry weight ）was3.0ˑ103-1.1ˑ105ind ·g －1．The microbial activity was reported as fluorescence content in per unit sediment mass （μg·g －1，dry weight ）．Key words ：coastal intertidal mudflat ；microbial activity ；FDA hydrolase analysis ；fluorescence spectrometry中国北方近海多属泥滩类潮间带，沉积环境中常常栖息着种类繁多、分布广泛的细菌、底栖微藻和原生动物等复杂的生物相，共同维持着生态系统的平衡，发挥其生态功能．微生物在生态系统中物质的降解、转化及能量流动过程中起着关键的控制作用［1 3］，其活性水平取决于各种生物、化学和物理因素以及环境营养状况［4］，如pH 值、介质、温度、水分、通气性和营养物质含量等［5］．微生物的活性直接影响着生物地球化学循环的活跃程度及生态系统的健康和稳定，与众多环境问题的研究密切相关．环境样品中微生物活性检测技术主要有碳呼吸、放射性标记物掺入细胞大分子、腺苷能荷和酶分析法，每种方法各有其适用范围［6］．其中酶活性分析法中的荧光素双醋酸酯（FDA ）水解酶活性是多种酶活性的体现，包括蛋白酶、脂肪酶和酯酶等［7，8］．FDA 水解酶活性作为一种快速、灵敏的测定环境样品微生物活性的方法，与微生物活性间的相关性比其他酶活性更显著，已经广泛用于表征不同环境中，特别是土壤环境中的微生物生物量［9，10］和总微生物活性［11 14］，其应用范围仍在不断扩展，从土壤到活性污泥［15］、溪流沉积生物滤膜［14］、农作物残余物［16］以及深海沉积物［17］．其中对深海沉积物微生物活性检测，仍采用常规环境样品检测方10期刘叶等：FDA水解酶分析法表征近海泥滩微生物活性法和条件，该方法针对高盐、低活性环境样品检测的适用性，有待验证和完善．FDA水解酶分析法的原理是：无色有机化合物FDA被胞外酶与膜结合酶水解，释放出黄色的高荧光产物荧光素，该高荧光产物稳定性强，可通过其产生量来表征微生物活性强度［12］．荧光素是一种亮黄色物质，在490nm可见光有较强吸收［9］，可用分光光度计检测，这是目前常用的检测方法．分光光度法检测限较高，灵敏度较低，对微生物活性较低的样品或样品间微生物活性的较小差异难以检测．荧光产物除了在可见光区有较强吸收，其在488nm激发下可发出530nm荧光，利用该荧光特性，可采用分子荧光法进行荧光强度检测；根据荧光素的标准曲线将荧光强度值换算成单位质量样品的荧光素含量（μg·g－1），来表征FDA被微生物酶水解的强弱，即微生物活性．相对于分光光度法，荧光光度法灵敏度高，检测限低，特征性强，尤其适用于微生物浓度或活性较低的样品的检测．目前荧光光度法表征微生物活性未见报道．泥滩类潮间带除了有机质组成复杂，具有泥砂质等复杂的沉积环境特点外，拥有独特的海洋微生物群落结构及复杂的生物相．而且，由于该方法属于酶活性分析法的范畴，所有影响酶活性的因素都将影响微生物活性分析，现有的一般土壤或水体样品微生物活性分析方法不适用于泥滩类沉积环境，因此要精确表征泥滩类沉积环境中微生物的活性，需要同时考虑其环境条件和微生物特点，有必要在现有方法的基础上，进一步优化或改动，以适用于近海泥滩类沉积环境中微生物活性的分析研究．本研究针对中国北方近海沉积环境的特点，从样品浸提液和反应产物检测仪器、预处理方法、实验条件等方面进行筛选和优化，建立适用于泥滩类沉积环境的FDA水解酶微生物活性检测分析方法．1材料与方法1.1实验材料供试样品选择有机质组成复杂、具有泥砂质特点的典型泥滩类沉积环境———胶州湾大沽河河口潮间带和黄河口潮间带，分别设置潮上、潮中、潮下带三类采样点，大沽河河口采样点为DA （36ʎ10'34.2ᵡN，120ʎ08'33.72ᵡE）、DB （36ʎ10'57.74ᵡN，120ʎ08'25.52ᵡE）和DC （36ʎ10'50.22ᵡN，120ʎ08'26.22ᵡE），黄河口采样点为YA（37ʎ43'52.26ᵡN，119ʎ14'51.96ᵡE）、YB （37ʎ43'56.76ᵡN，119ʎ14'57.3ᵡE）和YC （37ʎ44'1.62ᵡN，119ʎ15'3.84ᵡE）．用预先灭菌的铝盒采集表层沉积物，快速盖上盒盖放入塑料袋中，避光冷藏暂存，至实验室尽快分析．1.2实验方法1.2.1样品浸提液和反应产物检测方法的选择实验常用的浸提液为磷酸缓冲液和陈海水．为了降低浸提液对测试结果的影响，本实验从两种常用浸提液中选择背景值较小的一种用于微生物活性测定．为了提高检测的灵敏度，分别采用分子荧光光度计和分光光度计进行分析测定，选择灵敏度较高的检测仪器用于微生物活性分析．分别取一定量的经灭菌处理的磷酸缓冲溶液（pH=7.6）和陈海水，加入适量荧光素双醋酸酯溶液（fluorescein diacetate，简称FDA，SIGMA公司，纯度为99.99%，使用前配制成1mg·mL－1溶液），振荡混匀，避光反应180min，分别采用荧光法（F4600分子荧光光度计，激发波长488nm，发射波长530 nm）和分光光度法（UV2550紫外可见分光光度计，490nm）测定反应产物的荧光强度和吸光度，并绘制荧光素的标准曲线．1.2.2样品预处理方法的优化由于样品泥砂质的特点，而且有机质组成复杂，为使样品能够均匀分散，在样品中加入常用分散剂吐温80，以使样品中的微生物更好地悬浮在浸提液中，制备成菌悬液．另外，泥滩类沉积环境中有大量底栖微藻、原生动物等生物相［18］，为了排除这些生物相对微生物活性测定的影响，实验采用1.2μm 滤膜过滤菌悬液后，进行微生物活性测定．（1）吐温-80分散剂对荧光反应的影响取一定量的样品浸提液，按照1%比例加入0.05%的吐温-80工作液，混合均匀，然后测试FDA 反应的荧光强度，确定吐温-80分散剂是否影响荧光反应．以不加吐温-80的浸提液为对照．（2）滤膜对荧光反应的影响菌悬液经无菌滤膜过滤后，虽然可以去除藻类、原生动物等对微生物活性反应的影响，但是滤膜上可能含有荧光物质或其他可溶性成分，成为潜在的荧光反应影响因素．本实验旨在研究和消除滤膜对荧光反应的影响．滤膜的无菌处理分别采用多次煮沸灭菌法［19］和蒸馏水中高压蒸汽灭菌法．取一定量的浸提液，9183环境科学34卷分别采用上述两种方法处理的滤膜过滤，测定滤液的荧光反应产物强度．同时以未过滤的浸提液作为对照．1.2.3荧光反应条件的优化泥滩沉积物经浸提和预处理，制成待测菌液，进行测试条件实验，确定最优反应条件．（1）FDA最适浓度确定待测菌液与不同终浓度FDA溶液反应，测定其荧光强度，最大荧光素含量时FDA的添加量作为FDA最适浓度．大沽河样品FDA终浓度梯度设置为：0、2.5、5.0、7.5、10.0μg·mL－1；黄河口样品FDA终浓度梯度设置为：0、3.0、6.0、9.0、10.0、12.0μg·mL－1．（2）终止剂的选择和有效终止时间范围的确定待测菌液与最适浓度的FDA反应后，加入4%的终止剂终止反应，在终止反应后50min内，每隔10min测定反应产物的荧光强度，根据荧光素含量的变化情况，确定最佳的终止剂和有效终止时间范围．分别以丙酮和氯仿/甲醇（2ʒ1，体积比）混合液为终止剂，设置不加终止剂的对照组．（3）最适反应温度的确定待测菌液与最适浓度FDA反应分别于15、20、25、30和35ħ下进行，通过反应产物的荧光强度，确定最适反应温度．（4）最适反应时间的确定在最适温度下，待测菌液与最适浓度FDA反应，分别于60、90、120、150、180和210min终止反应，在有效终止时间段测定荧光强度，确定最适反应时间．1.2.4方法检测范围的确定对泥滩样品中微生物进行稀释和浓缩，利用4'，6-二脒基-2-苯基吲哚盐酸（DAPI）进行细胞染色［20］，以表面荧光显微计数法确定微生物的浓度，根据方法可靠检出荧光信号的最低限和最高限，制备不同微生物浓度梯度的泥滩样品，确定方法检测范围．2结果与讨论2.1样品浸提液和反应产物检测仪器的选择荧光强度与荧光素浓度呈线性正相关关系，回归方程y=9626.9x，r=0.9969，式中，y指荧光强度；x指荧光素含量（μg·mL－1）；r指相关系数．根据回归方程荧光强度可用荧光素浓度表示．分子荧光光度法和分光光度法测定结果如表1和图1所示．陈海水的背景荧光强度明显低于磷酸缓冲液的背景荧光强度（P＜0.01），后者约为前者的2.4倍，分光光度法测定的两种浸提液的吸光值平均结果虽然都为0.000，但两种反应产物具有微弱可见的色度差别．因此实验选择背景荧光强度较低的陈海水作为微生物浸提液，选择灵敏度较高的分子荧光光度计为反应产物的检测仪器．近海沉积物中微生物丰度一般在103 105个·g－1［21 23］，而一般土壤中可超过1010个·g－1，河流、湖泊中数浓度在104 109个·mL－1，在富营养污染区微生物数浓度往往会升高2 3个数量级［24］．本实验样品微生物量的实测结果大概在103 104个·g－1．表明相对普通水体和陆地土壤环境来说，潮间带样品微生物量较低．所以分光光度法测定近海沉积物样品中微生物活性误差较大，而反应产物具有高荧光特性，成为检测方法的依据．图1不同浸提液对荧光反应的影响Fig．1Impact of different extracts on the fluorescence reaction表1分子荧光光度计和分光光度计对反应产物的荧光强度和吸光值的检测结果Table1Fluorescence intensity and the absorbance values of the reaction product by molecular fluorescence photometer and spectrophotometer样品浸提液分子荧光光度计分光光度计123均值123均值磷酸缓冲液37653675389937800.0000.0000.0010.000陈海水15651388166215380.0000.0000.0000.0002.2样品预处理方法的优化2.2.1吐温-80分散剂对荧光反应的影响吐温-80分散剂的影响结果见图2，添加和未添加吐温-80反应后的荧光素含量无明显差异（P＞028310期刘叶等：FDA 水解酶分析法表征近海泥滩微生物活性0.05），表明适量的分散剂吐温-80对荧光反应基本无影响．但是适量吐温-80分散剂使样品均匀分散，微生物更好地悬浮在浸提液中，提高提取效果．图2吐温-80分散剂对荧光反应的影响Fig．2Impact of Tween-80solution on the fluorescence reaction2.2.2滤膜对荧光反应的影响滤膜对荧光反应的影响结果见图3，经煮沸灭菌和高压灭菌的滤膜过滤处理的陈海水反应产物的荧光素含量，分别高于未过滤陈海水荧光素含量的24.5%和33.2%，表明滤膜上可能存在某些影响荧光测定的荧光物质［25］，或影响荧光反应的可溶性物质．该物质伴随过滤除藻、原生动物等过程，被引入到菌悬液中．多次煮沸灭菌的滤膜与高压蒸汽灭菌的滤膜，对荧光反应的影响无明显差异（P ＞0.05）．但是相图4不同FDA 浓度下的荧光素含量Fig．4Fluorescence at different FDA concentration对于对照组，多次煮沸灭菌处理方式对反应荧光素含量的影响，比高压蒸汽灭菌方式对反应荧光素含量的影响低8.7%．因此，采用多次煮沸灭菌法处理滤膜，并通过扣除膜空白的方法，去除滤膜对荧光反应的影响．2.3反应条件的优化2.3.1FDA 最适浓度确定不同浓度梯度FDA溶液反应的荧光素含量见实验组1（未过滤陈海水）、实验组2（煮沸滤膜过滤）、实验组3（高压灭菌滤膜过滤）图3滤膜对荧光反应的影响Fig．3Impact of membrane on the fluorescence reaction图4.当胶州湾大沽河口样品FDA 浓度不高于7.5μg ·mL －1，或黄河口样品FDA 浓度不高于10.0μg ·mL －1时，反应产物的荧光素含量与FDA 浓度呈正相关关系，荧光素含量逐渐增大，表明FDA 的水解程度不断增加，样品的反应强度不断增强．当胶州湾大沽河样品FDA 浓度高于7.5μg ·mL －1，或黄河口样品FDA 浓度高于10.0μg ·mL －1时，反应产物出现混浊现象，表明FDA 加入过量，无法进行荧光强度测定．当胶州湾大沽河口样品FDA 浓度低于5.0μg ·mL －1，或黄河口样品FDA 浓度低于6.0μg ·mL －1时，荧光素含量随FDA 浓度增加变化较快；当FDA 浓度分别在5.0 7.5μg·mL －1或6.0 10μg ·mL －1时，荧光素含量随FDA 浓度增加变化不大，可以作为最适FDA 浓度范围．因此，胶州湾大沽河口样品最适FDA 浓度为7.5μg·mL －1，黄河口样品最适FDA 浓度为10.0μg ·mL －1．2.3.2终止剂的选择及有效终止时间范围的确定实验开始阶段FDA 水解反应迅速，随后反应速度大幅度降低．但是持续的慢反应将影响样品间的1283环境科学34卷可比性，因此需要加入快速终止酶反应的终止剂，终止FDA 的水解反应，再进行荧光强度测定，以提高样品间的可比性．图5终止液的终止效果Fig．5Termination effect of the stop bufferFDA 法终止剂通常采用丙酮或氯仿/甲醇（2ʒ1，体积比）混合液．本实验结果表明，丙酮和氯仿/甲醇（2ʒ1体积比）混合液都有一定程度的终止效应，在加入终止剂后25min 内，荧光素含量的变化范围分别是1.4 8.6%和0.6 3.9%，变化均较小，无显著性差异（P ＞0.05），25min 之后荧光素含量均表现了明显增强．有研究表明，丙酮终止剂使吸光度降低，不能准确测定活性较低的土壤样品（砂土、黏土）；氯仿/甲醇（2ʒ1，体积比）混合液能够终止土壤样品的水解反应，而不会引起颜色损失［12，13］．本实验没有发现两种终止剂的明显区别，并且采用分子荧光光度法，而非分光光度法，因此丙酮和氯仿/甲醇（2ʒ1，体积比）混合液都可以作为终止液，但是氯仿/甲醇（2ʒ1，体积比）混合液作为终止剂，使反应结果的荧光素含量大都略低于丙酮终止剂的荧光素含量，使荧光素含量大概降低0.5% 9.2%，故而选择丙酮作为反应终止剂．综上所述，25min 范围内微生物活性的荧光反应都呈现较好的终止效果（图5），这与Green 等［26］研究结果相似．所有样品应该在有效终止时间内测定完毕．2.3.3最适反应温度的确定反应温度对荧光反应的影响结果如图6所示，反应产物的荧光素含量在15 25ħ之间与温度呈正比关系，25 30ħ之间荧光素含量的变化较小，当反应温度超过30ħ时，荧光素含量均出现明显下降的趋势，当温度达60ħ时，大部分酶均已失活［26］；这与酶的最适反应温度有关，酶在温度升高后不同程度地失活，导致微生物活性逐渐降低．泥滩类沉积环境微生物群落属于海洋微生物，大部分海洋微生物最佳生长温度在25 30ħ范围内［27］．因此，选择25 30ħ作为微生物活性测定的最适反应温度，此温度下FDA 水解酶活性最高，对FDA 的水解量228310期刘叶等：FDA水解酶分析法表征近海泥滩微生物活性图6不同反应温度下的荧光素含量Fig．6Fluorescence at different reaction temperature最大，微生物活性也最强．2.3.4最适反应时间的确定反应时间与荧光素含量的关系如图7所示，反应荧光素含量随时间延长不断增强；当进行到150min 时，反应速率开始降低；180min 之后荧光素含量趋于变化缓慢、平稳．所以最适反应时间为180min ；这与报道的土壤样品的最适反应时间基本一致［13，26］．图7不同反应时间下的荧光素含量Fig．7Fluorescence at different reaction time2.4方法检测范围的确定如图8所示，在103 105个·g －1范围内不同微生物（干重，下同）数浓度的样品活性呈良好的线性关系（r =0.9956）．根据在最优检测条件下测得空白对照的荧光强度值，加倍所对应的微生物数浓度作为方法检测范围的最低值，测得值为3.0ˑ103个·g －1．当微生物浓度超过1.1ˑ105个·g －1时，受该仪器检测限的限制（荧光强度值＜105），而无法进行荧光强度的检测．该方法的检测范围是3.0ˑ103 1.1ˑ105个·g －1，适用于一般泥滩类沉积环境中微生物活性的检测［21 23］．3结论（1）盐效应和低含量，是检测海洋环境样品的关键问题，也是不能与陆地环境样品检测方法直接通用的主要原因．近海和河口区域潮间带沉积物中微生物活性的检测，除了高盐和低含量，还面临介质图8荧光素含量的线性响应范围Fig．8Linear response range of the fluorescence signals组成复杂，以及pH 、营养要素和动力扰动剧烈等问题．针对于此，本研究根据微生物酶水解FDA 产生荧光素的特性，以河口泥滩沉积物为实验材料，建立3283环境科学34卷海洋沉积环境微生物活性的荧光光度检测方法．该方法具有检出限低、灵敏度高和干扰小的特点，不仅适用于高盐、低含量的近海潮间带区域沉积物中微生物活性检测，而且可以延伸至深远海环境沉积物微生物活性检测．（2）荧光素双醋酸酯（FDA）法检测微生物活性的方法如下：称取一定量泥滩类沉积环境样品，加入适量的灭菌陈海水，再按照1%的比例加入样品分散剂0.05%的吐温-80工作液，充分振荡均匀分散后，静置片刻使较大颗粒自然沉降；取上层悬浊液，通过1.2μm的无菌滤膜（多次煮沸灭菌）过滤，得到待测菌液．不加样品的对照组（灭菌陈海水）需经同样的滤膜过滤，以消除滤膜对荧光反应的影响；加入适量的FDA，混合均匀，在25 30ħ下避光反应180min，再加入丙酮终止反应，并在加入终止剂后25min反应时间内，采用分子荧光光度计（激发波长488nm，发射波长530nm）测定反应产物的荧光强度，该方法的检测范围是3.0ˑ103 1.1ˑ105个·g－1．微生物活性以单位质量（干重）样品的荧光素含量表示（μg·g－1）．参考文献：［1］Nixdorf B，Jander J．Bacterial activities in shallow lakes-a comparison between extremely acidic and alkaline eutrophic hardwater lakes［J］．Hydrobiologia，2003，506/509（1-3）：697-705．［2］Deming J W，Baross J A．The early diagenesis of organic matter：bacterial activity［A］．In：Engel M H，Macko S A（Eds．）．Organic Geochemistry［C］．New York：Plenum Press，1993.119-144．［3］Blackburn T H．Microbial food webs in sediments［A］．In：Sleigh M A（Eds．）．Microbes in the Sea［C］．New York：JohnWiley and Sons，1987.355-359．［4］Marika T，Jaanis J，Jaak T．Microbial biomass，activity and community composition in constructed wetlands［J］．Science ofthe Total Environment，2009，407（13）：3958-3971．［5］郑有飞，石春红，吴芳芳，等．土壤微生物活性影响因子的研究进展［J］．土壤通报，2009，40（5）：1209-1214．［6］张甲耀，宋碧玉，陈兰洲，等．环境微生物学［M］．武汉：武汉大学出版社，2008.243-248．［7］Guilbault G G，Kramer D N．Fluorometric determination of lipase，acylase，alpha-，and gamma-chymotrypsin and inhibitorsof these enzymes［J］．Analytical Chemistry，1964，36（2）：409-412．［8］Rotman B，Papermaster B W．Membrane properties of living mammalian cells as studied by enzymatic hydrolysis of fluorogenicesters［J］．Proceedings of the National Academy of Sciences ofthe United States of America，1966，55（1）：134-141．［9］Stubberfield L C F，Shaw P J A．A comparison of tetrazolium reduction and FDA hydrolysis with other measures of microbialactivity［J］．Journal of Microbiological Methods，1990，12（3-4）：151-162．［10］Gaspar M L，Cabello M N，Pollero R，et al．Fluorescein diacetate hydrolysis as a measure of fungal biomass in soil［J］．Current Microbiology，2001，42（5）：339-344．［11］Swisher R，Carroll G C．Fluorescein diacetate hydrolysis as an estimator of microbial biomass on coniferous needle surfaces［J］．Microbial Ecology，1980，6（3）：217-226．［12］Schnürer J，Rosswall T．Fluorescein diacetate hydrolysis as a measure of total microbial activity in soil and litter［J］．Appliedand Environmental Microbiology，1982，43（6）：1256-1261．［13］Adam G，Duncan H．Development of a sensitive and rapid method for the measurement of total microbial activity usingfluorescein diacetate（FDA）in a range of soils［J］．Soil Biologyand Biochemistry，2001，33（7-8）：943-951．［14］Battin T J．Assessment of fluorescein diacetate hydrolysis as a measure of total esterase activity in natural stream sedimentbiofilms［J］．Science of the Total Environment，1997，198（1）：5l-60．［15］Fontvieille D A，Outaguerouine A，Thevenot D R．Fluorescein diacetate hydrolysis as a measure of microbial activity in aquaticsystems：Application to activated sludges［J］．EnvironmentalTechnology，1992，13（6）：531-540．［16］Zablotowicz R M，Locke M A，Smeda R L．Degradation of2，4-D and fluometuron in cover crop residues［J］．Chemosphere，1998，37（1）：87-101．［17］Gumprecht R，Gerlach H，Nehrkorn A．FDA hydrolysis and resazurin reduction as a measure of microbial activity in sedimentsfrom the south-east Atlantic［J］．Helgoland Marine Research，1995，49（1-4）：189-199．［18］姚晓，山口一岩，邹立，等．黄河三角洲南部潮间带沉积环境对底栖叶绿素a分布特征的影响［J］．生态学杂志，2010，29（9）：1762-1769．［19］GB5749-2006，生活饮用水卫生标准［S］．［20］朱澂，林辰涛．一种新型的DNA荧光染料———DAPI的光学特性及其应用［J］．武汉植物学研究，1986，4（1）：91-102．［21］乔旭东，唐学玺，肖慧，等．渤海湾近岸海域的细菌数量分析［J］．中国海洋大学学报（自然科学版），2007，37（2）：273-276．［22］肖慧，唐学玺，乔旭东，等．渤海湾天津近岸表层沉积物中细菌丰度及其与环境因子的相关性研究［J］．中国海洋大学学报（自然科学版），2010，40（6）：87-90．［23］史君贤，陈忠元，胡锡钢．南鹿列岛附近海域表层水及沉积物中细菌的丰度及其在环境中的作用［J］．东海海洋，1994，12（3）：57-61．［24］张甲耀，宋碧玉，陈兰洲，等．环境微生物学［M］．武汉：武汉大学出版社，2008.13-26．［25］李影，段锐，钱爱东．“活的非可培养状态”细菌荧光显微镜检测技术［J］．中国动物检疫，2010，27（2）：43-44．［26］Green V S，Stott D E，Diack M．Assay for fluorescein diacetate hydrolytic activity：Optimization for soil samples［J］．Soil Biologyand Biochemistry，2006，38（4）：693-701．［27］张晓华，李筠，纪伟尚，等．海洋微生物学［M］．青岛：中国海洋大学出版社，2007.315-336．4283。

2022年全国硕士研究生招生考试英语(一)模拟卷

2022年全国硕士研究生招生考试英语(一)模拟卷（江南博哥）材料题根据下面资料，回答1-20题Decades of scientific research show that stress and anxiety are prevalent problems at work, contributing to deficits in employee morale, well-being, andproductivity.1anxiety is caused by a range of2, including issues unrelated to people's jobs, one common and3cause is something specific to the workplace: incompetent leadership.Managers and leaders have a4effect on their employees' stress and anxiety levels.5they say, feel, and do hugely influences their team's6and emotionalwell-being. And the more senior leaders are, the more people they are likely to influence—positively and7.8sadly, far too few leaders are aware that they have this power. And many are overconfident in their leadership skills,9a gap between their perceived and actual levels of10. This explains why even well-meaning bosses may inadvertently11high anxiety levels in their employees and have a12capacity to correct and improve their behavior：13you think you are leading effectively, what is the point of changing?It is for this14that leaders must pay a great deal of15to how they act and communicate. The importance of this is exacerbated during times of increased uncertainty,16we often look to leaders to guide us in the face of fear, to provide uswith17and direction, and, most of all, to give us reasons to18hopeful and optimistic.If you are a manager or a leader, it is useful to19some key psychological lessons about how your behavior—what you say, do, feel, and express—20your team, especially when you are not aware of it.1 [单选题]第（1）题选A.BecauseB.SinceC.WhileD.When正确答案：C参考解析：空格处需要填入一个连词，体现前后两个分句的逻辑关系。

GRE阅读考试资料

GRE阅读考试资料During experiments at the Bimini Biological Research Station in the Bahamas， researchers Eric Stroud and Michael Hermann dropped a small mag in the water beside a shark。

The presence of the mag elicited a distinct reaction from the fish －－ they darted away from it。

Why the intense reaction？ The interaction of salt water and charged metals produces a weak electrical field。

When a shark es close to that field， the field seems to disrupt the sharks‘ special sixth sense，electroreception。

Many shark species have pores dotted around their snouts called ampullae of Lorenzinithat detect minute changes of electricity in the seawater， up to one－billionth of a volt。

These electrical impulses e from the tiniest muscle contractions of other aquatic life forms －－ or people －－ and are carried through the ions in the salt water。

海洋探测的英语作文

海洋探测的英语作文The Frontiers of Ocean Exploration.The vast expanse of the ocean covers more than 70% ofthe Earth's surface, yet remains one of the least explored frontiers of human knowledge. Ocean exploration, a fieldthat encompasses the study of marine biology, geology, chemistry, and physics, among others, holds the key to unlocking the mysteries of our planet's most mysterious domain.The importance of ocean exploration cannot be overstated. The ocean is a critical component of the global ecosystem, regulating climate, influencing weather patterns, and supporting a diverse array of marine life. Furthermore, the ocean holds vast resources, including oil, gas, andother minerals, as well as potential new sources ofmedicine and biotechnology.Advancements in technology have been crucial in pushingthe boundaries of ocean exploration. Remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) have enabled scientists to explore deep-sea environments that were once inaccessible. These vehicles are equipped with high-resolution cameras, sonar equipment, and other sensors that allow for precise mapping and sampling of the seabed.In addition to technological advancements, ocean exploration has also been enhanced by international collaboration. The International Seabed Authority (ISA), established under the United Nations Convention on the Law of the Sea (UNCLOS), promotes cooperation among nations in the exploration and exploitation of the resources of the international seabed area. Such collaborations have led to the discovery of new species, understanding of geological processes, and the development of sustainable exploitation methods.One of the most significant areas of ocean exploration is the study of deep-sea ecosystems. These environments, which are often characterized by low light levels, highpressure, and limited oxygen, are home to a unique array of marine life. Deep-sea corals, for example, form complex ecosystems that support a diverse range of organisms, including many that are still unknown to science. The study of these ecosystems is crucial for understanding the impact of human activities, such as fishing and climate change, on marine biodiversity.Another key aspect of ocean exploration is the search for new resources. The seabed is rich in minerals,including polymetallic nodules, cobalt-rich crusts, and hydrothermal vents. These resources, which are found in areas beyond national jurisdiction, have the potential to contribute significantly to global economies. However, the extraction of these resources must be balanced with the need to protect the fragile ecosystems that they inhabit.The future of ocean exploration looks bright. With advances in technology and increasing international collaboration, we are poised to make significant discoveries that will further our understanding of the ocean and its role in the global ecosystem. However, it iscrucial that we approach this frontier with caution and respect, ensuring that our explorations are conducted in a sustainable and responsible manner.In conclusion, ocean exploration represents a frontier of knowledge and discovery that holds immense value for humanity. By leveraging the latest technologies and fostering international collaboration, we can unlock the mysteries of the deep sea and ensure that our actions are beneficial for both science and society.。

水产动物传染病学知到章节答案智慧树2023年上海海洋大学

水产动物传染病学知到章节测试答案智慧树2023年最新上海海洋大学第一章测试1.The three main aquaculture groups including species recorded by FAO ascultured in 2012 except the .参考答案:parasite2.The Top 3 Countries in Global Aquaculture Production in 2012a exceptthe .参考答案:Japan3.( ) are the principal pathogens that are negatively affecting aquacultureworldwide.参考答案:viruses4.Several strategies that are used to successfully rear terrestrial farm animalsin intensive production systems are also used to prevent and control viraldiseases in aquaculture, including strategies below except the for increased resistance against diseases.参考答案:Antibiotics5. Aquatic animal virology started in the early 1960s using data forcrustaceanviruses (Vago, 1966) and with the establishment of fish cell linesfor the isolation of piscine viruses.参考答案:EM morphological第二章测试1.The principles of the Baltimore classification are fundamental to anunderstanding of virus below except the .参考答案:Structure2.OIE published standard protocols in the OIE Aquatic Manual (OIE, 2014) fordetection and identification of pathogens on the OIE list of notifiable aquatic animal diseases in 2015 included eight fish viral diseases including bellows except the .参考答案:Rhabdovirus olivacens3.OIE published standard protocols in the OIE Aquatic Manual (OIE, 2014) fordetection and identification of pathogens on the OIE list of notifiable aquatic animal diseases in 2015 included six crustacean viral diseases includingbellows except the .参考答案:Infection with abalone herpesvirus4.（) can induce beneficial effects in multiple ways for managing themicrobiota in aquaculture systems.参考答案:Probiotics5.（）is the major abiotic vector involved in aquatic diseases transmission.参考答案:Water第三章测试1. Spring viremia of carp (SVC) belong to the categoryⅠ（一类）in the List ofanimal diseases of Ministry of Agriculture（农业部一、二、三类疫病名录。

基于分子生物学的长江口外海域中微生物鉴定

基于分子生物学的长江口外海域中微生物鉴定摘要：作为国家卫星海洋中心组成部分，本论文主要是初步查明秋季长江口外海域海洋悬浮物中的微生物种类。

2008年秋季，我们在长江口外海域采集的海洋悬浮物样品，利用对海洋微生物16SrRNA基因的直接扩增，克隆和测序，从而鉴定微生物的种类。

通过开展本研究，我们希望能初步查明长江口外海域海洋悬浮物中的微生物种类，为建立海洋微生物分子生物学检测的技术体系打下一定的基础。

关键词：海洋微生物，种类鉴定，16SrRNA，海洋悬浮物I dentifications of Microorganism from the Outside waters of Changjiang River Estuary by Molecular Biology TechniquesAbstract: Being as a major part of Satellite Ocean Center of China , this study is trying to primarily investigate the microorganism species in the Suspended solids from the Outside waters of Changjiang River Estuary。

In fall in 2008, we collected Suspended solids samples from the biology investigation spot 24 of Satellite Ocean Center of China, then identified the marine microorganism species by using direct amplifications of 16S rRNA gene from marine microorganism, cloning and sequencing techniques. In this study, we hope to identify the marine organism species in sediment from the China East Sea near to Shanghai, which could provide basis for the establishments of marine microorganism molecular detection technique system.Key words:Marine microorganism, species identification, 16SrRNA, marine sediments基于分子生物学的长江口外海域中微生物鉴定DNA电泳迁移率的对数与凝胶浓度成线性关系。

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2. Observations
Our study is based on longitudinal magnetograms acquired with the Narrowband Filter Imager (NFI; Tarbell et al. 2008) aboard Hinode. On November 14, 2006, the NFI observed the isolated spot AR 10923 from 07:10 to 09:40 UT and from 11:00 to 17:10 UT. The instrument was tuned to measure the Stokes I and V signals of Fe 630.25 nm at −120 mÅ from line center. The magnetograms cover a ﬁeld of view (FOV) of 328′′ × 164′′ , and have an irregular cadence of 1-5 minutes. The eﬀective pixel size of the measurements is 0′′ . 16, which gives a spatial resolution of about 0′′ . 32. The spectral resolution of the NFI is 90 mÅ. The spot crossed the central meridian around 10 UT, reaching a minimum heliocentric angle of 6◦ . The data have not been corrected for instrumental eﬀects because of diﬃculties in constructing accurate ﬂatﬁelds. We therefore restrict our analysis to the polarity of the magnetic ﬁeld. The polarity should be insensitive to spatial variations in the instrument transmission because it is obtained as the diﬀerence of two intensity measurements. Single wavelength magnetograms, such as the ones used here, may fail to retrieve the polarity of the ﬁeld in the presence of large Doppler shifts or multilobed Stokes V spectra. These proﬁles are common in sunspot penumbrae because of their strong Evershed ﬂows (e.g., Schlichenmaier & Collados 2002; Bellot Rubio et al. 2007). However, in sunspots close to
A. Sainz Dalda1,2 and L.R. Bellot Rubio3
1 2 3
arXiv:0712.2983v2 [astro-ph] 20 Jan 2008
THEMIS S.L., C/V´ ıa L´ actea s/n, 38200 La Laguna, Tenerife, Spain Instituto de Astrof´ ısica de Canarias , C/V´ ıa L´ actea s/n, 38200 La Laguna, Tenerife, Spain Instituto de Astrof´ ısica de Andaluc´ ıa, CSIC, Apdo. 3004, 18080 Granada, Spain
Astronomy & Astrophysics manuscript no. ms˙sainz February 2, 2008
c ESO 2008
L E
Detection of sea-serpent ﬁeld lines in sunspot penumbrae
Key words. Sunspots – Sun: magnetic ﬁelds – Sun: photosphere – Magnetohydrodynamics (MHD)
1. oduction
Signiﬁcant progress in the understanding of the penumbra has been made through high resolution magnetograms and Dopplergrams (Title et al. 1993; Schlichenmaier & Schmidt 2000; Langhans et al. 2005; Rimmele & Marino 2006), spectropolarimetric measurements (Degenhardt & Wiehr 1991; S´ anchez Almeida & Lites 1992; Lites et al. 1993; Stanchﬁeld et al. 1997; R¨ uedi et al. 1999; Westendorp Plaza et al. 2001; Schlichenmaier & Collados 2002; Mathew et al. 2003; Bellot Rubio et al. 2004; Borrero et al. 2005, 2006; S´ anchez Cuberes et al. 2005; Beck 2006; Jurˇ ca ´ k et al. 2007), and forward modeling (Mart´ ınez Pillet 2000; M¨ uller et al. 2002). Today it is agreed that the penumbra consists of magnetic ﬁelds having diﬀerent inclinations and strengths, as proposed by Solanki & Montavon (1993) in their uncombed penumbral model. One particularly relevant result derived from spectropolarimetry is that some ﬁeld lines return to the solar interior well within the penumbra. The modest angular resolution of ground-based polarimeters has precluded an unambiguous direct detection of such oppositepolarity ﬁeld lines or the study of their temporal evolution. Also, in recent years there has been an increased interest in determining the relation between moving magnetic features (MMFs; Harvey & Harvey 1973) and penumbral magnetic ﬁelds. There is growing observational evidence that bipolar MMFs are the continuation of the more horizontal magnetic ﬁelds of the penumbra in the sunspot moat (Sainz Dalda & Mart´ ınez Pillet 2005; Ravindra 2006; Cabrera Solana et al. 2006; Kubo et al. 2007a), but a clear picture has not yet emerged due to insuﬃcient angular resolution. Establishing the small-scale organization of the magnetic ﬁeld in the penumbra is crucial to shed light on these issues, and also to distinguish between competing models of the penum-
Received / Accepted
ABSTRACT
Aims. We investigate the spatial distribution of magnetic polarities in the penumbra of a spot observed very close to disk center. Methods. High angular and temporal resolution magnetograms taken with the Narrowband Filter Imager aboard Hinode are used in this study. They provide continuous and stable measurements in the photospheric Fe 630.25 line for long periods of time. Results. Our observations show small-scale, elongated, bipolar magnetic structures that appear in the mid penumbra and move radially outward. They occur in between the more vertical ﬁelds of the penumbra, and can be associated with the horizontal ﬁelds that harbor the Evershed ﬂow. Many of them cross the outer penumbral boundary, becoming moving magnetic features in the sunspot moat. We determine the properties of these structures, including their sizes, proper motions, footpoint separation, and lifetimes. Conclusions. The bipolar patches can be interpreted as being produced by sea-serpent ﬁeld lines that originate in the mid penumbra and eventually leave the spot in the form moving magnetic features. The existence of such ﬁeld lines has been inferred from Stokes inversions of spectropolarimetric measurements at lower angular resolution, but this is the ﬁrst time they are imaged directly. Our observations add another piece of evidence in favor of the uncombed structure of penumbral magnetic ﬁelds.