Hypothalamic regulation of sleep and circadian rhythms

A series of findings over the past decade has begun to identify the brain circuitry and neurotransmitters that regulate our daily cycles of sleep and wakefulness. The latter depends on a network of cell groups that activate the thalamus and the cerebral cortex. A key switch in the hypothalamus shuts off this arousal system during sleep. Other hypothalamic neurons stabilize the switch, and their absence results in inappropriate switching of behavioural states, such as occurs in narcolepsy. These findings explain how various drugs affect sleep and wakefulness, and provide the basis for a wide range of environmental influences to shape wake-sleep cycles into the optimal pattern for survival.     

根田鼠肝糖元水平昼夜节律及低氧影响

在自然光照下,根田鼠肝糖元水平有一个昼夜节律,一天中含量存在两个高峰,一个是在1:00的30.8±7.6mg/g湿重,另一个为15:00的29.7±9.4mg/g湿重,最低是在20:00的14.8±1.7mg/g湿重.在低氧7Km2h和24h下,肝糖元呈下降趋势,但不呈显著水平(P>0.05).     

The loss of ions from Venus through the plasma wake

Venus, unlike Earth, is an extremely dry planet although both began with similar masses, distances from the Sun, and presumably water inventories. The high deuterium-to-hydrogen ratio in the venusian atmosphere relative to Earth's also indicates that the atmosphere has undergone significantly different evolution over the age of the Solar System. Present-day thermal escape is low for all atmospheric species. However, hydrogen can escape by means of collisions with hot atoms from ionospheric photochemistry, and although the bulk of O and O2 are gravitationally bound, heavy ions have been observed to escape through interaction with the solar wind. Nevertheless, their relative rates of escape, spatial distribution, and composition could not be determined from these previous measurements. Here we report Venus Express measurements showing that the dominant escaping ions are O+, He+ and H+. The escaping ions leave Venus through the plasma sheet (a central portion of the plasma wake) and in a boundary layer of the induced magnetosphere. The escape rate ratios are Q(H+)/Q(O+) = 1.9; Q(He+)/Q(O+) = 0.07. The first of these implies that the escape of H+ and O+, together with the estimated escape of neutral hydrogen and oxygen, currently takes place near the stoichometric ratio corresponding to water.     

地球化学小波分析在火山旋回韵律厘定中的应用——以埃塞俄比亚北部施瑞地区为例

以埃塞俄比亚北部施瑞地区变火山岩系为典型实例,阐述变火山岩系火山旋回的岩性岩相特征,并在此基础上探讨利用地球化学含量小波分析识别火山旋回韵律的技术与方法.通过地质地球化学剖面对比分析,选择具有代表性的地球化学元素Si和Fe+Mg含量作为分析对象,选择db5小波基进行三尺度小波分解与重构.提取有关旋回韵律演化的信息,综合对比各地质剖面的空间分布特征,变火山岩系共划分出6个旋回15个韵律.研究结果表明:经小波处理后的地球化学含量有效去除了局部噪音干扰;小波分析在火山旋回厘定中不仅可有效划分区域火山旋回,而且可有效判别旋回中的韵律.     

论全球化语境中的民族文化独立性

经济全球化必然带来化的全球性发展。化全球化给各国化发展带来的既是机遇，也是挑战。能否保持民族化的独立性，将在很大程度上决定着中华民族化的发展前景，并最终影响到我国社会主义的前途和命运。保持民族化独立性，关键在于大力弘扬和培育民族精神，积极发展化产业，借鉴中西化的精华，创造出中国特色社会主义的新型化，以增强中华民族化的吸引力和感召力。     

论商主体的独立性

随着市场经济的深入发展,用民事主体涵盖商主体的弊端在学理和立法方面日益显露出来。承认商主体的独立性,有利于妥善解决理论和实践中的问题,完善我国的民商事法律体系。     

Simulated change in the near-surface soil freeze/thaw cycle on the Tibetan Plateau from 1981 to 2010

The near-surface freeze/thaw cycle in cold regions plays a major role in the surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,the Community Land Model,Version 4 and a suite of high-resolution atmospheric data were used to investigate the changes in the near-surface soil freeze/thaw cycle in response to the warming on the Tibetan Plateau from1981 to 2010.The in situ observations-based validation showed that,considering the cause of scale mismatch in the comparison,the simulated soil temperature,freeze start and end dates,and freeze duration at the near-surface were reasonable.In response to the warming of the Tibetan Plateau at a rate of approximately 0.44°C decade-1,the freeze start-date became delayed at an area-mean rate of1.7 days decade-1,while the freeze end-date became advanced at an area-mean rate of 4.7 days decade-1.The delaying of the freeze start-date,which was combined with the advancing of the freeze end-date,resulted in a statistically significant shortening trend with respect to the freeze duration,at an area-mean rate of 6.4 days decade-1.Such changes would strongly affect the surface energy flux,hydrological processes,and vegetation dynamics.We also found that the rate of freeze-duration shortening at the near-surface soil layer was approximately 3.0 days decade-1lower than that at a depth of 1 m.This implied that the changes in soil freeze/thaw cycles at the near surface cannot be assumed to reflect the situation in deeper soil layers.The significant correlations between freeze duration and air temperature indicated that the shortening of the near-surface freeze duration was caused by the rise in air temperature,which occurred especially in spring,followed by autumn.These results can be used to reveal the laws governing the response of the near-surface freeze/thaw cycle to climate change and indicate related changes in permafrost.     

Banach空间中框架的独立性

引入并研究了Banach空间中框架的独立性,证明了Banach空间及其对偶空间可以通过任意一个关于lp的Banach框架或独立p阶框架重构.     

鱼游尾迹中射流分布特征的数值模拟研究

本文采用一种通过控制仿生鱼摆频来达到自主推进状态的数值模拟方法,研究了不同雷诺数下二维仿生鱼自主游动时尾迹中射流的分布特征,并通过模拟两条鱼串列和交错排列时的自主游动,分析了上游鱼的尾迹对下游鱼的影响．结果表明：仿生鱼尾迹中射流的强度随着雷诺数的增大而减小,射流的空间影响域随雷诺数增大而增大;鱼游尾迹中的射流虽然可以导致下游鱼的阻力增加,但能耗却会降低,这与前人的假想恰好相反;而且随着两条鱼间距离的增大,尾迹中的射流会逐渐减弱为低速区,从而导致下游鱼的阻力小于单条鱼游动时的阻力,节能效果更加显著．本文的研究结果将有利于深入理解鱼群中的节能机制以及鱼群的最优排列方式．     

论独立董事的独立性

独立董事制度是公司治理全球化浪潮中的一项重要成果。独立董事制度的作用体现在：能有效防止董事会被大股东和管理层所控制和能完善董事会的决策制度。独立董事的独立性和真正保持独立董事的独立性是整个独立董事制度的核心所在。独立董事的独立性可以划分为两个主要层次，即：作为当选要件的独立性和作为任职要求的独立性。独立性主要体现在：独立董事的职权的独立、责任的独立、信息的独立和薪酬的独立等方面。但是独立董事的独立性在制度的实际运行中却往往会遇到例如选举中大股东操控、经营信息不对称、薪酬制度的依附性等实际情况。有效的针对措施包括：独立董事的薪酬与公司脱钩；股东大会采用民主投票的方式选举董事；经营信息透明化；实行独立董事任期制度等，而最重要的是对独立董事实施法律监督，使其行为法制化。     

蒙古独立外因探源

蒙古独立问题前后经历约半个世纪 ,其外部原因与沙俄、苏俄、苏联的扩张主义 ,二战结束前美国的大国主义及蒋介石政府的集团利益驱动是分不开的。它是大国政治交易的结果 ,是苏美强权政治的产物     

再论人格权法的独立

在私法的发展史上,相较于财产权的发展来说,人格权无疑是新型的权利。然而人格权从来就不是一个单纯的法律问题,人本主义哲学思想时刻影响并促进了其发展。随着人的自我意识的提高,现代民法不再以"财产权"为中心而展开,而应"人格权"和"财产权"并重,赋予了人格权独立的法律地位。人格权的独立成编无疑是新近民法典的发展趋势,因此我国要制定一部面向"21世纪的民法典"就必须顺势而为,在法典的篇章结构上确立人格权法的独立地位。     

浅论内部审计的独立性

内部审计的独立性是其发挥作用的根本保证.独立性能够使内部审计师做出公正的裁断,有利于内部审计的正常实施.加强内部审计的独立性,必须加强内部审计的法制建设,保证审计人员的独立性,建立独立、健全的内审机构,提高内部审计人员素质等.     

注册会计师审计独立性丧失原因之分析

独立性是注册会计师行业的灵魂，独立性包括形式上的独立和实质上的独立两个方面，但当前注册会计师行业正面临着独立性丧失的不利局面，究其原因，主要表现在公司治理结构缺陷、审计业务多样化、经济利益关系、会计师事务所规模、会计师事务所本身性质等五个方面。     

Large eddy simulation of the gas-particle turbulent wake flow

To find out the detailed characteristics of the coherent structures and associated particle dispersion in free shear flow, large eddy simulation method was adopted to investigate a two-dimensional particleladen wake flow. The well-known Sub-grid Scale mode introduced by Smagorinsky was employed to simulate the gas flow field and Lagrangian approach was used to trace the particles. The results showed that the typical large-scale vortex structures exhibit a stable counter rotating arrangement of opposite sign, and alternately form from the near wall region, shed and move towards the downstream positions of the wake with the development of the flow. For particle dispersion, the Stokes number of particles is a key parameter. At the Stokes numbers of 1.4 and 3.8 the particles concentrate highly in the outer boundary regions. While the particles congregate densely in the vortex core regions at the Stokes number of 0. 15, and the particles at Stokes number of 15 assemble in the vortex braid regions and the rib regions between the adjoining vortex structures.