Functional organization of the second cortical visual area in primates

The functional organization of the second cortical visual area was examined with three different anatomical markers: 2-[14C]deoxy-D-glucose, cytochrome oxidase, and various myelin stains. All three markers revealed strips running throughout the area, parallel to the cortical surface. The boundaries of these strips provide an anatomical criterion for defining the borders of this extrastriate region. Further, the demonstration of these strips allows a functional and anatomical analysis of modules in the area, just as the recent demonstration of spots in the primary visual cortex has allowed an analysis of modules there. The strips differ structurally and functionally from interstrip regions and these differences are similar to those seen between the spots and the interspot regions in the primary visual cortex. In the macaque the strips and spots differ with regard to binocular organization.     

Hierarchical organization of modularity in metabolic networks

Spatially or chemically isolated functional modules composed of several cellular components and carrying discrete functions are considered fundamental building blocks of cellular organization, but their presence in highly integrated biochemical networks lacks quantitative support. Here, we show that the metabolic networks of 43 distinct organisms are organized into many small, highly connected topologic modules that combine in a hierarchical manner into larger, less cohesive units, with their number and degree of clustering following a power law. Within Escherichia coli, the uncovered hierarchical modularity closely overlaps with known metabolic functions. The identified network architecture may be generic to system-level cellular organization.     

A cortical area selective for visual processing of the human body

Despite extensive evidence for regions of human visual cortex that respond selectively to faces, few studies have considered the cortical representation of the appearance of the rest of the human body. We present a series of functional magnetic resonance imaging (fMRI) studies revealing substantial evidence for a distinct cortical region in humans that responds selectively to images of the human body, as compared with a wide range of control stimuli. This region was found in the lateral occipitotemporal cortex in all subjects tested and apparently reflects a specialized neural system for the visual perception of the human body.     

Neuroscience. Regional differences in cortical organization

Although there are elegants maps of the human brain that reveal differences in cellular architecture between different cortical regions, there is not much information about how corresponding cortical regions differ between the left and right hemispheres. As Gazzaniga explains in his Perspective, new results reveal the surprising finding of asymmetry in area 22 (which is important for language processing) of the left and right hemisphere (Galuske et al.). Clusters of neurons in area 22 of the left hemisphere are spaced farther apart and have longer axons cabling them together than neuronal clusters in area 22 of the right hemisphere.     

福建农村中介组织建设刍议

世界发达国家现代农业产业化的实践表明,健全有效的农村中介组织是现代农业的基本载体,是农业产业化的重要一环.我国加入世贸组织后,农业和农村将更加直接参与激烈的国际市场竞争,农业和农村经济将面临许多新的机遇和挑战.福建农业外向度比较高,如何在加快农业结构战略性调整的同时,按照WTO农业规则,调整国内相关政策,积极培育有国际竞争力的市场主体和农村中介组织,提高农业产业化经营水平,为农产品在国际市场上的"抢滩登陆"保驾护航,是个很值得研究的问题.本文根据笔者统计调查的资料,对福建农村中介组织建设进行一些粗浅的探讨.     

Pertussis toxin gene: nucleotide sequence and genetic organization

The current pertussis vaccines, although efficacious, in some instances produce undesirable side effects. Molecular engineering of pertussis toxin, the major protective antigen, could provide a safer, new generation of vaccines against whooping cough. As a first critical step in the development of such a vaccine, the complete nucleotide sequence of the pertussis toxin gene was determined and the amino acid sequences of the individual subunits were deduced. All five subunits are coded by closely linked cistrons. A promoter-like structure was found in the 5'-flanking region, suggesting that the toxin is expressed through a polycistronic messenger RNA. The order of the cistrons is S1, S2, S4, S5, and S3. All subunits contain signal peptides of variable length. The calculated molecular weights of the mature subunits are 26,024 for S1, 21,924 for S2, 21,873 for S3, 12,058 for S4, and 11,013 for S5. Subunits S2 and S3 share 70% amino acid homology and 75% nucleotide homology. Subunit S1 contains two regions of eight amino acids homologous to analogous regions in the A subunit of both cholera and Escherichia coli heat labile toxins.     

The neostriatal mosaic: striatal patch-matrix organization is related to cortical lamination

The basal ganglia, of which the striatum is the major component, process inputs from virtually all cerebral cortical areas to affect motor, emotional, and cognitive behaviors. Insights into how these seemingly disparate functions may be integrated have emerged from studies that have demonstrated that the mammalian striatum is composed of two compartments arranged as a mosaic, the patches and the matrix, which differ in their neurochemical and neuroanatomical properties. In this study, projections from prefrontal, cingulate, and motor cortical areas to the striatal compartments were examined with the Phaseolus vulgaris-leucoagglutinin (PHA-L) anterograde axonal tracer in rats. Each cortical area projects to both the patches and the matrix of the striatum; however, deep layer V and layer VI corticostriatal neurons project principally to the patches, whereas superficial layer V and layer III and II corticostriatal neurons project principally to the matrix. The relative contribution of patch and matrix corticostriatal projections varies among the cortical areas examined such that allocortical areas provide a greater number of inputs to the patches than to the matrix, whereas the reverse obtains for neocortical areas. These results demonstrate that the compartmental organization of corticostriatal inputs is related to their laminar origin and secondarily to the cytoarchitectonic area of origin.     

Determining optimal leaf surface area

In field experiments with local application of various dosages of fertilizer on chernozem soils in northwestern Povolzhye, the optimal development of leaf area in millet plants of Kamyshinskoe 67 variety was revealed. A maximum leaf area of 58 500 m²/ha was noted in the phase of panicle emergence with the application of N₁₅₅P₈₈K₁₄₃. Such a leaf surface area ensured an output of 63.7 cwt/ha on average over three years of production.     

Optimization of millet and buckwheat leaf surface area

The optimal development of the leaf area of millet and buckwheat plants is determined in field experiments with the local application of fertilizers in various doses and combinations on chernozem soils in the steppe zone of the Southern Urals. The maximum millet leaf area of 37400 m²/ha is noted in the heading stage with the application of N₉₀P₉₀ and that of buckwheat 36200 m²/ha in the flowering stage with the application of P₆₀.     

DEM在林地表面积计算中的应用研究

土地的表层利用情况与人类的生产生活息息相关,而对于土地利用中处于斜坡上的林地来说,其表面积比投影面积更具有意义,然而目前还没有找到一种高效、精确的计算其表面积方法;本文以重庆江津市为研究区域,利用等高线模拟地形,运用微积分的方法对林地的表面积的计算方法进行了探讨;研究结果表明在数据有限的情况下,此方法能够比较准确的计算林地的表面积,且比用投影面积乘以坡度的平均正割值所计算的面积更精确。     

Convergent projection of three separate thalamic nuclei on to a single cortical area

Three distinct sensory-motor nuclei in the thalamus project to parietal cortex in the Virginia opossum; the ventral posterior nucleus receives inputs from somatic sensory structures and projects to layers IV and III, the ventral anterolateral nucleus receives inputs from motor structures and projects to layers IV and III and inner I, and the central intralaminar nucleus receives inputs from sensory, motor, and other structures and projects to layers VI through outer I. The physiologically defined amalgamation of somatic sensory and motor cortex is correlated, therefore, with the extent of cortex that receives convergent somatic sensory and motor input from the thalamus.     

枣果实表面积估算模型的研究

【目的】果实表面积是发育生理学研究的一个重要特征,同时也是植物病理学研究分析的重要指标。【方法】本试验采用包裹法测定3个不同果形枣品种的表面积,尝试4种测算模型对枣果实表面积进行拟合计算。【结果】基于‘板枣’体积和‘婆婆枣’横径线性回归模型,‘壶瓶枣’质量非线性回归模型更能估测枣果实表面积,回归方程分别为:y=2.9132x+2.7707,r=0.9767;y=2.1551x-22.318,r=0.9887;y=6.1831x0.7321,r=0.9851。     

Hierarchical organization of guidance receptors: silencing of netrin attraction by slit through a Robo/DCC receptor complex

Axonal growth cones that cross the nervous system midline change their responsiveness to midline guidance cues: They become repelled by the repellent Slit and simultaneously lose responsiveness to the attractant netrin. These mutually reinforcing changes help to expel growth cones from the midline by making a once-attractive environment appear repulsive. Here, we provide evidence that these two changes are causally linked: In the growth cones of embryonic Xenopus spinal axons, activation of the Slit receptor Roundabout (Robo) silences the attractive effect of netrin-1, but not its growth-stimulatory effect, through direct binding of the cytoplasmic domain of Robo to that of the netrin receptor DCC. Biologically, this hierarchical silencing mechanism helps to prevent a tug-of-war between attractive and repulsive signals in the growth cone that might cause confusion. Molecularly, silencing is enabled by a modular and interlocking design of the cytoplasmic domains of these potentially antagonistic receptors that predetermines the outcome of their simultaneous activation.     

新疆艾比湖流域耕地面积变化对艾比湖湖面面积的影响分析

基于1950～2009年艾比湖流域耕地面积与湖面面积历史数据和卫星影像数据,研究艾比湖流域耕地面积变化对艾比湖湖面面积的影响。结果表明,艾比湖每年3～4月湖面面积最大,而4月以后特别是7月后,湖面面积减小;2000～2009年艾比湖湖面面积最大的是在2003～2004年,湖面面积最小的是在2008～2009年,且湖面面积呈逐年减小的趋势;艾比湖流域的耕地面积不断增加,且增速逐年增长,以2005～2009年的增加速度最高;相关性分析显示,艾比湖流域耕地面积与湖面面积之间呈线性负相关,且显著相关,表明流域耕地面积的增加会直接导致湖面面积的减少。     

Chromatographic silica gel: surface area determined by adsorption

The surface area of silicic acid, a form of silica gel, has been determined by adsorption of methanol from a benzene solvent. The method is straightforward, uses inexpensive apparatus, and should be applicable to other particulate adsorbents.     

Gene therapy for human genetic disease?

In our view, gene therapy may ameliorate some human genetic diseases in the future. For this reason, we believe that research directed at the development of techniques for gene therapy should continue. For the foreseeable future, however, we oppose any further attempts at gene therapy in human patients because (i) our understanding of such basic processes as gene regulation and genetic recombination in human cells is inadequate; (ii) our understanding of the details of the relation between the molecular defect and the disease state is rudimentary for essentially all genetic diseases; and (iii) we have no information on the short-range and long-term side effects of gene therapy. We therefore propose that a sustained effort be made to formulate a complete set of ethicoscientific criteria to guide the development and clinical application of gene therapy techniques. Such an endeavor could go a long way toward ensuring that gene therapy is used in humans only in those instances where it will prove beneficial, and toward preventing its misuse through premature application. Two recent papers have provided new demonstrations of directed genetic modification of mammalian cells. Munyon et al. (44) restored the ability to synthesize the enzyme thymidine kinase to thymidine kinase-deficient mouse cells by infection with ultraviolet-irradiated herpes simplex virus. In their experiments the DNA from herpes simplex virus, which contains a gene coding for thymidine kinase, may have formed a hereditable association with the mouse cells. Merril et al. (45) reported that treatment of fibroblasts from patients with galactosemia with exogenous DNA caused increased activity of a missing enzyme, alpha-D-galactose-l-phosphate uridyltransferase. They also provided some evidence that the change persisted after subculturing the treated cells. If this latter report can be confirmed, the feasibility of directed genetic modification of human cells would be clearly demonstrated, considerably enhancing the technical prospects for gene therapy.     

甘南玛曲地区地表温度的变化特征

【目的】分析甘南玛曲地区地表温度的变化特征及其变化趋势,为该地区生态环境的可持续发展提供参考。【方法】利用甘南玛曲地区1971-2010年的地表温度观测数据,用线性趋势分析、小波分析及突变分析等方法,对玛曲地区40年的年际、年代际、突变年份及地表温度与气温的关系等气候变化特征进行分析。【结果】甘南玛曲地区平均地表温度以0.6 ℃/10a的速率升高,2000年之后升幅达到1.9 ℃/10a。各季节平均地表温度呈现出不同程度的升高趋势,最高、最低平均地表温度亦呈升高趋势,平均地表温度的升高主要以最低地表温度的上升为主。甘南玛曲地区年平均地表温度2000年之前为负距平,2000年之后为正距平变化;各季节平均地表温度在进入2000年后升幅加剧,且以冬季上升的趋势最为显著;1971-2010年最低地表温度的升幅明显大于最高地表温度,最高、最低地表温度均表现出以20世纪70年代最低、2001-2010年间最高的年代际变化特征。平均地表温度存在较为明显的准7年短周期和12～13年长周期;年及各季节平均地表温度均发生了增高突变,其中年及春、秋季增高突变均发生在20世纪80年代,夏、冬季发生在20世纪90年代;且以春季平均地表温度发生突变的时间最早,出现在1984年。年平均气温与地表温度在变化趋势上具有很强的一致性,两者的相关系数达到0.93,呈显著正相关。【结论】地表温度不断升高和超载过牧,均促进了甘南玛曲地区草地退化的进程和草地沙化的发生发展,降低对草地生态系统的依赖与干扰是该地区草地资源得以可持续发展的有效途径。     

湖南农村人力资源开发与管理

农村人力资源的开发与管理是社会经济发展的一个重要课题。湖南是一个农业大省,农村劳动力过剩,但文化素质却不高。应因地制宜发展农村职业教育,调整产业结构,有序转移剩余劳动力。     

Slow compressional wave propagation in wet human and bovine cortical bone

Ultrasonic wave propagation in bovine plexiform and human Haversian bone was studied in the range 0.5 to 15 megahertz. A new longitudinal wave was observed which traveled more slowly than the ordinary longitudinal wave. The slow wave was associated with the dynamics of fluid motion in the pores of bone.