新疆高校足球选项课教学的现状及时对策研究

采用问卷调查法、文献资料法、访谈法．逻辑分析法对当前新疆高校开设足球选项课教学的现状进行分析,提出了应转变足球教学的指导思想改革现有的足球教学模式、建足球健身教学体系、丰富教学内容和教学形式、完善教学考核评价制度等对策与建议,以尽快解决当前高校足球教学中的问题,使之在素质教育中发挥更大的作用。     

纤维对PEI改性环氧树脂单向复合材料形态的影响

人们改善环氧树脂基复合材料的脆性通常只改善环氧树脂基体和增强纤维间的界面，提高环氧树脂韧性的另一种常用方法是添加初始相容性良好的热塑性树脂如聚醚酰亚胺，在某一转化率（取决于体系的组成和反应温度）时体系发生相转变，体系最终的形态由相转变速率和环氧树脂反应速度所控制。本文作者研究了两种增强纤维（玻璃纤维和碳纤维）对不同环氧树脂／聚醚酰亚爱体系形态形成的影响，结果发现体系中纤维的存在不会影响基体相分离过程，但会改变体系的最终形态；形态的变化与纤维的品种关系不大；基体中不同组分的粘度是影响复合材料形态形成的关键因素。     

Design and fabrication of 1-D semiconductor nanomaterials for high-performance photovoltaics

To date, the cost-effective utilization of solar energy by photovoltaics for large-scale deployment remains challenging. Further cost minimization and efficiency maximization, through reduction of material consumption, simplification of device fabrication as well as optimization of device structure and geometry, are required. The usage of 1D nanomaterials is attractive due to the outstanding light coupling effect, the ease of fabrication, and integration with one-dimensional(1-D) semiconductor materials. The light absorption efficiency can be enhanced significantly, and the corresponding light-toelectricity conversion efficiency can be as high as their bulk counterparts. Also, the amount of active materials used can be reduced. This review summarizes the recent development of 1-D nanomaterials for photovoltaic applications, including the anti-reflection, the light absorption,the minority diffusion, and the semiconductor junction properties. With solid progress and prospect shown in the past 10 years, 1-D semiconductor nanomaterials are attractive and promising for the realization of high-efficiency and low-cost solar cells.     

Fingerprints of global warming on wild animals and plants

Over the past 100 years, the global average temperature has increased by approximately 0.6 degrees C and is projected to continue to rise at a rapid rate. Although species have responded to climatic changes throughout their evolutionary history, a primary concern for wild species and their ecosystems is this rapid rate of change. We gathered information on species and global warming from 143 studies for our meta-analyses. These analyses reveal a consistent temperature-related shift, or 'fingerprint', in species ranging from molluscs to mammals and from grasses to trees. Indeed, more than 80% of the species that show changes are shifting in the direction expected on the basis of known physiological constraints of species. Consequently, the balance of evidence from these studies strongly suggests that a significant impact of global warming is already discernible in animal and plant populations. The synergism of rapid temperature rise and other stresses, in particular habitat destruction, could easily disrupt the connectedness among species and lead to a reformulation of species communities, reflecting differential changes in species, and to numerous extirpations and possibly extinctions.     

Symmetrical directional cloning: An efficient method to prepare hairpin RNA interference constructs

RNA interference (RNAi) is a loss-of-function approach by which double-stranded RNA (dsRNA) initiates degradation of homologous mRNAs in a sequence specific manner. The dsRNA molecules can be produced in vitro or in vivo, and can be introduced to cells in a number of ways. Here we report a more efficient method for the cloning of inverted repeat DNA fragments into expression vectors that can be transcribed into effective dsRNA molecules in vivo or in vitro. This method, named Symmetrical Directional Cloning (SDC), takes the advantage of compatible non-palindromic restriction enezyme sites, which allow one to directionally clone a single PCR product in both the sense and antisense orientations together into a vector. SDC allows for the directional cloning of inverted repeats using a single PCR product; it requires only one cut site on each side of the loop. Hence this method is more cost effective and less time-consuming. At least 21 commercially available restriction endonucleases can be used as cloning sites for the SDC method. The efficacy of dsRNA expression vectors prepared by SDC has been demonstrated by targeting a negative regulator of the signaling pathway mediating the response of cells to phytohormone, gibberellins (GA), in the aleurone cells.     

Adelfa： a futuristic biodiesel fuel for DI diesel engines： a comparative experimental investigation

Biodiesel fuel is found to be a promising alter- native for the petroleum diesel based on the results published by the researchers for a decade. Biodiesel fuel is renewable and non degradable fuel. Many countries use biodiesel fuel for automotives to meet the crisis due to the depletion of the petroleum fuel and to meet the stringent emission norms. Various researches have been carried out with different bio- diesel fuels with vegetable oil as the source and appreciable results were reported. Few biodiesel fuels which have been already tested are Jatropha, Pongamia, Mahua, neem, cotton seed, etc. In this experimental work, Adelfa biodiesel blend is used as the test fuel. The emission and performance charac- teristics were compared with three other different biodiesel fuel blends. Appreciable results imply that Adelfa biodiesel （Nerium oil methyl ester） can be a futuristic biodiesel fuel, which has a good compatibility with the direct injection （DI） diesel engine without any major modification. Moreover, Adelfa can be cultivated in a non agricultural land with fewer sources of water. It is widely spread over all major countries of Asia. Experimental investigations have been carried out on a single cylinder DI diesel engine with standard engine speci- fications. In this experimental work, various Adelfa biodiesel blends is compared with reference fuel （diesel） to choose the best blend which gives a closer performance to diesel. The comparative analysis with other biodiesel fuels has also been done and results have been discussed.     

Temporal precision in the neural code and the timescales of natural vision

The timing of action potentials relative to sensory stimuli can be precise down to milliseconds in the visual system, even though the relevant timescales of natural vision are much slower. The existence of such precision contributes to a fundamental debate over the basis of the neural code and, specifically, what timescales are important for neural computation. Using recordings in the lateral geniculate nucleus, here we demonstrate that the relevant timescale of neuronal spike trains depends on the frequency content of the visual stimulus, and that 'relative', not absolute, precision is maintained both during spatially uniform white-noise visual stimuli and naturalistic movies. Using information-theoretic techniques, we demonstrate a clear role of relative precision, and show that the experimentally observed temporal structure in the neuronal response is necessary to represent accurately the more slowly changing visual world. By establishing a functional role of precision, we link visual neuron function on slow timescales to temporal structure in the response at faster timescales, and uncover a straightforward purpose of fine-timescale features of neuronal spike trains.     

SLAC1 is required for plant guard cell S-type anion channel function in stomatal signalling

Stomatal pores, formed by two surrounding guard cells in the epidermis of plant leaves, allow influx of atmospheric carbon dioxide in exchange for transpirational water loss. Stomata also restrict the entry of ozone--an important air pollutant that has an increasingly negative impact on crop yields, and thus global carbon fixation and climate change. The aperture of stomatal pores is regulated by the transport of osmotically active ions and metabolites across guard cell membranes. Despite the vital role of guard cells in controlling plant water loss, ozone sensitivity and CO2 supply, the genes encoding some of the main regulators of stomatal movements remain unknown. It has been proposed that guard cell anion channels function as important regulators of stomatal closure and are essential in mediating stomatal responses to physiological and stress stimuli. However, the genes encoding membrane proteins that mediate guard cell anion efflux have not yet been identified. Here we report the mapping and characterization of an ozone-sensitive Arabidopsis thaliana mutant, slac1. We show that SLAC1 (SLOW ANION CHANNEL-ASSOCIATED 1) is preferentially expressed in guard cells and encodes a distant homologue of fungal and bacterial dicarboxylate/malic acid transport proteins. The plasma membrane protein SLAC1 is essential for stomatal closure in response to CO2, abscisic acid, ozone, light/dark transitions, humidity change, calcium ions, hydrogen peroxide and nitric oxide. Mutations in SLAC1 impair slow (S-type) anion channel currents that are activated by cytosolic Ca2+ and abscisic acid, but do not affect rapid (R-type) anion channel currents or Ca2+ channel function. A low homology of SLAC1 to bacterial and fungal organic acid transport proteins, and the permeability of S-type anion channels to malate suggest a vital role for SLAC1 in the function of S-type anion channels.     

泰国木薯淀粉特性研究

木薯是热带地区碳水化合物的主要来源.木薯根的化学组成,淀粉含量,淀粉质量和淀粉性质常常决定木薯作为食品和工业用的价值.对广泛种植在泰国的2个木薯品种Kasetsart50(KU50)和Rayong5(R5)块根的化学组成、淀粉质量和淀粉性质分析结果表明:KU50比R5品种具有高的淀粉含量,高的氢氰酸含量和高的灰分含量.2个品种淀粉粒大小和直链淀粉含量并没有显著的差异.在85℃下KU50比R5具有高的膨润度.差示扫描量热仪测定的热力学特征为:KU50具有高的糊化起始温度、糊化结束温度、糊化峰值温度和热函.2个品种的淀粉粘度曲线差异较小.由此得出:从提取淀粉效率来说,KU50优于R5;作为饲料加工业,R5的饲料品质优于KU50;对于淀粉深加工业,因KU50和R5具有不同的热力学性质和粘度性质,因而根据加工产品的不同而具有不同的优缺点.