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Questions 17～20 are based on the following talk. You now have 20 seconds to read Questions 17～20. According to the speaker, how do developers contribute to the reduction of amphibian population
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Questions 17～20 are based on the following talk. You now have 20 seconds to read Questions 17～20. According to the speaker, why do pesticides pose a threat to amphibians
某投资公司建造一幢办公楼，采用公开招标方式选择施工单位。招标文件要求：提交投标文件和投标保证金的截止时间为2009年5月30日。该投资公司于2009年3月6日发出招标公告，共有5家建筑施工单位参加了投标。第5家施工单位于2009年6月2日提交了投标保证金。开标会于2009年6月3日由该省建委主持。第4家施工单位在开标前向投资公司要求撤回投标文件和退还投标保证金。经过综合评选，最终确定第2家施工单位中标。投资公司(甲方)与中标单位(乙方)双方按规定签订了施工承包合同，合同约定开工日期为2009年8月16日。工程开工后发生了如下几项事件。事件一：因拆迁工作拖延，甲方于2009年8月18日才向乙方提供施工场地，导致乙方A、B两项工作延误了2天，并分别造成人工窝工6个和8个工日；但乙方C项工作未受影响。事件二：乙方与机械设备租赁商约定，D项工作施工用的某机械应于2009年8月28日进场，但因出租方原因推迟到当月29日才进场，造成D工作延误1天和人工窝工7个工日。事件三：因甲方设计变更，乙方在E项工作施工时，导致人工增加14个工日，相关费用增加了1.5万元，并使施工时间增加了2天。事件四：在F项工作施工时，因甲方供材出现质量缺陷，乙方施工增加用工6个工日，其他费用1000元，并使H项工作时间延长1天，人工窝工24个工日。上述事件中，A、D、H三项工作均为关键工作，没有机动时间，其余工作均有足够的机动时间。[问题] 第5家施工单位提交投标保证金的时间对其投标文件产生什么影响？为什么？
A UCSF study has revealed new information about how the brain directs the body to make movements. The key factor is "noise" in the brain’s signaling, and it helps explain why all movement is not carried out with the same level of precision. Understanding where noise arises in the brain has implications for advancing research in neuromotor control and in developing therapies for disorders where control is impaired, such as Parkinson’s disease. The new study was developed "to understand the brain machinery behind such common movements as typing, walking through a doorway or just pointing at an object," says Stephen Lisberger, PhD, senior study investigator who is director of the W.M. Keck Center for Integrative Neuroscience at the University of California, San Francisco. Study co-investigators are Leslie C. Osborne, PhD, a postdoctoral fellow at UCSF, and William Bialek, PhD, professor of physics at Princeton University. The study findings, reported in the September 15 issue of the journal Nature; are part of ongoing research by Lisberger and colleagues on the neural mechanisms that allow the brain to learn and maintain skills and behavior. These basic functions are carried out through the coordination of different nerve cells within the brain’s neural circuits. "To make a movement, the brain takes the electrical activity of many neurons and combines them to make muscle contractions," Lisberger explains. "But the movements aren’t always perfect. So we asked, what gets in the way" The answer, he says, is "noise", which is defined as the difference between what is actually occurring and what the brain perceives. He offers making a foul shot in basketball as an example. If there were no noise in the neuromotor system, a player would be able to perform the same motion over and over and never miss a shot. "Understanding how noise is reduced to very precise commands helps us understand how those commands are created," says Lisberger, who also is a Howard Hughes Medical Institute investigator and a UCSF professor of physiology. In the study, the research team focused on a movement that all primates are very skilled at: an eye movement known as "smooth pursuit" that allows the eyes to track a moving target. In a series of exercises with monkeys in which the animals would track visual targets, the researchers measured neural activity and smooth pursuit eye movements. From this data, the team analyzed the difference between how accurately the animals actually tracked a moving object and how accurately the brain perceived the trajectory. Findings showed that both the smooth pursuit system and the brain’s perceptual system were nearly equal. "This teaches us that these very different neural processes are limited to the same degree by the same noise sources," says Lisberger. "And it shows that both processes are very good at reducing noise." He concludes, "Because the brain is noisy, our motor systems don’t always do what it tells us to. Making precise movements in the face of this noise is a challenge.\ The findings of the study with monkeys show that
MemorandumTo: All employees at Focus FilmsFrom: Peter Bates, Personnel ManagerDate: October 7thSubject: 1. The Canteen Manageress2. Canteen Pricesa. I’m sorry to say that Mrs. Jenkins, our canteen manageress, is ill in hospital. As you know, the cafeteria is very busy between 11 and 12 o’clock. We would like some extra help while Mrs. Jenkins is away. If you can help any day next week can I have your name before Friday, October 9thb. From Monday, October 12th, coffee and sandwiches will cost 2p extra, and all the others on the cafeteria menu 1p extra.Signed: Peter BatesMemorandumThis memorandum was signed by (46) .Mrs. Jenkins was away, because she (47) .All the employees were required to give (48) .If someone could work extra hours the following week, his/her name should be (49) to the personnel manager before October 9th.Coffee and sandwiches would be increased by (50) from October 12th. 48（）
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