Early experience of tactile stimulation influences organization of somatic sensory cortex

Visual experience is essential for the establishment of the cerebral cortical circuitry that allows normal binocular vision. For example, the pattern of right-eye, left-eye dominance columns is permanently altered by simply closing an eye of a young primate. A critical issue is whether environmental factors also influence the development of other cortical sensory areas. In the present experiments we manipulated the tactile experience of young rats by depriving them of the sensory information that is normally provided by their large facial whiskers. Electrophysiological analyses showed that simply trimming the whiskers from the day of birth results in pronounced abnormalities in the response properties of single neurons in the adult somatic sensory cortex. Thus functional plasticity in response to early experience appears to be a fundamental aspect of cortical development.     

Mutations in the gene encoding the lamin B receptor produce an altered nuclear morphology in granulocytes (Pelger-Huët anomaly)

Pelger-Hu?t anomaly (PHA; OMIM *169400) is an autosomal dominant disorder characterized by abnormal nuclear shape and chromatin organization in blood granulocytes. Affected individuals show hypolobulated neutrophil nuclei with coarse chromatin. Presumed homozygous individuals have ovoid neutrophil nuclei, as well as varying degrees of developmental delay, epilepsy and skeletal abnormalities. Homozygous offspring in an extinct rabbit lineage showed severe chondrodystrophy, developmental anomalies and increased pre- and postnatal mortality. Here we show, by carrying out a genome-wide linkage scan, that PHA is linked to chromosome 1q41-43. We identified four splice-site, two frameshift and two nonsense mutations in LBR, encoding the lamin B receptor. The lamin B receptor (LBR), a member of the sterol reductase family, is evolutionarily conserved and integral to the inner nuclear membrane; it targets heterochromatin and lamins to the nuclear membrane. Lymphoblastoid cells from heterozygous individuals affected with PHA show reduced expression of the lamin B receptor, and cells homozygous with respect to PHA contain only trace amounts of it. We found that expression of the lamin B receptor affects neutrophil nuclear shape and chromatin distribution in a dose-dependent manner. Our findings have implications for understanding nuclear envelope-heterochromatin interactions, the pathogenesis of Pelger-like conditions in leukemia, infection and toxic drug reactions, and the evolution of neutrophil nuclear shape.     

宁夏南部黄土高原地区土地适宜性评价研究

根据联合国粮农组织（ＦＡＯ）土地评价纲要的分类体系，采用定性与定量相结合的方法，对宁夏南部黄土高原地区的土地进行了适宜性评价，并给出了该地区的土地适宜性能、质量等级、数量分布及亚级的数量和分布特征．     

基于SUMO软件的异构交通流仿真平台车辆模型开发与集成

采用实车参数和实际道路试验数据对基于SUMO软件的车辆模型进行优化,构建了具备自动驾驶全工况测试能力的高保真车辆运行特性模型,并与SUMO软件交通流仿真集成,形成了面向混合异构交通流的仿真平台。最后,通过典型交通运行场景对集成效果进行准确性和可用性验证。     

Odorous urine following asparagus ingestion in man

Summary The production of odorous urine after the ingestion of asparagus has been shown to occur in 43% of 800 volunteers investigated. This characteristics is reproducible over a 12-month-period and has been shown to remain with individuals for virtually a lifetime. Family studies suggest that the ability to produce the odorous urine is inherited as an autosomal dominant trait.     

Experimental demonstration of chaos in a microbial food web

Discovering why natural population densities change over time and vary with location is a central goal of ecological and evolutional disciplines. The recognition that even simple ecological systems can undergo chaotic behaviour has made chaos a topic of considerable interest among theoretical ecologists. However, there is still a lack of experimental evidence that chaotic behaviour occurs in the real world of coexisting populations in multi-species systems. Here we study the dynamics of a defined predator-prey system consisting of a bacterivorous ciliate and two bacterial prey species. The bacterial species preferred by the ciliate was the superior competitor. Experimental conditions were kept constant with continuous cultivation in a one-stage chemostat. We show that the dynamic behaviour of such a two-prey, one-predator system includes chaotic behaviour, as well as stable limit cycles and coexistence at equilibrium. Changes in the population dynamics were triggered by changes in the dilution rates of the chemostat. The observed dynamics were verified by estimating the corresponding Lyapunov exponents. Such a defined microbial food web offers a new possibility for the experimental study of deterministic chaos in real biological systems.