Multimodal fast optical interrogation of neural circuitry

Our understanding of the cellular implementation of systems-level neural processes like action, thought and emotion has been limited by the availability of tools to interrogate specific classes of neural cells within intact, living brain tissue. Here we identify and develop an archaeal light-driven chloride pump (NpHR) from Natronomonas pharaonis for temporally precise optical inhibition of neural activity. NpHR allows either knockout of single action potentials, or sustained blockade of spiking. NpHR is compatible with ChR2, the previous optical excitation technology we have described, in that the two opposing probes operate at similar light powers but with well-separated action spectra. NpHR, like ChR2, functions in mammals without exogenous cofactors, and the two probes can be integrated with calcium imaging in mammalian brain tissue for bidirectional optical modulation and readout of neural activity. Likewise, NpHR and ChR2 can be targeted together to Caenorhabditis elegans muscle and cholinergic motor neurons to control locomotion bidirectionally. NpHR and ChR2 form a complete system for multimodal, high-speed, genetically targeted, all-optical interrogation of living neural circuits.     

Genome-wide detection and characterization of positive selection in human populations

With the advent of dense maps of human genetic variation, it is now possible to detect positive natural selection across the human genome. Here we report an analysis of over 3 million polymorphisms from the International HapMap Project Phase 2 (HapMap2). We used 'long-range haplotype' methods, which were developed to identify alleles segregating in a population that have undergone recent selection, and we also developed new methods that are based on cross-population comparisons to discover alleles that have swept to near-fixation within a population. The analysis reveals more than 300 strong candidate regions. Focusing on the strongest 22 regions, we develop a heuristic for scrutinizing these regions to identify candidate targets of selection. In a complementary analysis, we identify 26 non-synonymous, coding, single nucleotide polymorphisms showing regional evidence of positive selection. Examination of these candidates highlights three cases in which two genes in a common biological process have apparently undergone positive selection in the same population:LARGE and DMD, both related to infection by the Lassa virus, in West Africa;SLC24A5 and SLC45A2, both involved in skin pigmentation, in Europe; and EDAR and EDA2R, both involved in development of hair follicles, in Asia.     

Adaptive subwavelength control of nano-optical fields

Adaptive shaping of the phase and amplitude of femtosecond laser pulses has been developed into an efficient tool for the directed manipulation of interference phenomena, thus providing coherent control over various quantum-mechanical systems. Temporal resolution in the femtosecond or even attosecond range has been demonstrated, but spatial resolution is limited by diffraction to approximately half the wavelength of the light field (that is, several hundred nanometres). Theory has indicated that the spatial limitation to coherent control can be overcome with the illumination of nanostructures: the spatial near-field distribution was shown to depend on the linear chirp of an irradiating laser pulse. An extension of this idea to adaptive control, combining multiparameter pulse shaping with a learning algorithm, demonstrated the generation of user-specified optical near-field distributions in an optimal and flexible fashion. Shaping of the polarization of the laser pulse provides a particularly efficient and versatile nano-optical manipulation method. Here we demonstrate the feasibility of this concept experimentally, by tailoring the optical near field in the vicinity of silver nanostructures through adaptive polarization shaping of femtosecond laser pulses and then probing the lateral field distribution by two-photon photoemission electron microscopy. In this combination of adaptive control and nano-optics, we achieve subwavelength dynamic localization of electromagnetic intensity on the nanometre scale and thus overcome the spatial restrictions of conventional optics. This experimental realization of theoretical suggestions opens a number of perspectives in coherent control, nano-optics, nonlinear spectroscopy, and other research fields in which optical investigations are carried out with spatial or temporal resolution.     

体质量对中华鳖(Pelodiscus sinensis)生化组成和质量能的影响

分别测定了在实验室条件下养殖的23只稚鳖(终末体质量为15.7～46.4 g)和38只幼鳖(终末体质量为57.5～283.7 g)鳖体的生化组成和质量能.结果表明:随着稚鳖、幼鳖体质量的增加,稚鳖和幼鳖鳖体的蛋白质、脂肪的质量分数和质量能均升高,而水分则随之降低(P＜0.01).稚鳖鳖体的灰分质量分数与体质量相关关系不明显(P＞0.05),而幼鳖的灰分质量分数随体质量增加而降低(P＜0.05).实验证实,以体质量为自变量来预测中华鳖稚鳖和幼鳖的蛋白质、脂肪的质量分数和质量能的方法是简单、可行的.     

Development and Prospect of China Uranium Mining and Metallurgy

The development of industry of uranium mining and metallurgy in China has been reviewed generally, emphasizing on investigation approaches and application levels of uranium mining technologies such as insitu leaching, heap leaching, stope leaching: on the basis of analysis on status of uranium mining and metallurgy and problems existed, also considering the specific features of deposit resources, the development orientation of uranium mining and metallurgy in China is pointed out. The industry of China uranium mining and metallurgy is faced to new opportunity of development and challenge in 21st century, the only way to realize sustainable development of uranium mining and metallurgy and harmonious development between economy and environment is to develop new technology on mining, ore beneficiation and metallurgy, increase the utilization level of uranium resources, low down impact on environment caused by mining and metallurgy.     

山东省湿地面积变化及其生态价值分析

笔者利用三期中国湿地数据,首次定量化研究山东省湿地在1990年、2000年2008年间的变化趋势,并对生态价值变化进行分析.结果显示,山东省湿地自然湿地从1990到2008年减少达到1 966.48 km2,减幅达到37.58%,面积变化先急促后迟缓.山东省湿地生态系统服务功能价值从1990年的374.82亿元,到2000年减少到333.18亿元,然而到2008年增长到了 373.38亿元,先减少后增加,同湿地面积变化趋势一致,这在总量上的增长,完全是人工湿地的增长,自然湿地一直在减少.