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).     

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.     

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.     

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。     

关于事件独立性的研究

为揭示事件独立性的本质,从独立性的定义出发,先对古典概型场合展开讨论,得出两事件相互独立的一个充要条件.而后将结论推广至一般概率空间的场合,并基于所得结论给出一种用于构造独立随机变量序列的具体方法.     

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.     

关于虚位移独立性的研究

从虚位移方程的基础解系出发探讨虚位移的独立性，并根据Четаев定义将其结果推广到高阶非完整系统。同时，根据对实位移的相应讨论，明确指出实位移是不相互独立的。