Large clusters of metal ions: the transition from molecular to bulk magnets

Clusters of metal ions are a class of compounds actively investigated for their magnetic properties, which should gradually change from those of simple paramagnets to those of bulk magnets. However, their interest lies in a number of different disciplines: chemistry, which seeks new synthetic strategies to make larger and larger clusters in a controlled manner; physics, which can test the validity of quantum mechanical approaches at the nanometer scale; and biology, which can use them as models of biomineralization of magnetic particles.     

From plant traits to plant communities: a statistical mechanistic approach to biodiversity

We developed a quantitative method, analogous to those used in statistical mechanics, to predict how biodiversity will vary across environments, which plant species from a species pool will be found in which relative abundances in a given environment, and which plant traits determine community assembly. This provides a scaling from plant traits to ecological communities while bypassing the complications of population dynamics. Our method treats community development as a sorting process involving species that are ecologically equivalent except with respect to particular functional traits, which leads to a constrained random assembly of species; the relative abundance of each species adheres to a general exponential distribution as a function of its traits. Using data for eight functional traits of 30 herbaceous species and community-aggregated values of these traits in 12 sites along a 42-year chronosequence of secondary succession, we predicted 94% of the variance in the relative abundances.     

FEAR AND PAIN: THEIR EFFECT ON SELF-INJECTION OF AMOBARBITAL SODIUM BY RATS

Rats receiving occasional brief electric shocks pressed a bar, which caused them to be injected with amobarbital sodium, more frequently than the control rats to which they were yoked and which were injected when their partners pressed but whose own bar activated only a recorder. This differential effect was not shown by pairs run without shocks.     

附红细胞体病的病原学及诊断学研究进展

附红细胞体病(Eperythrozoonosis)是近年来才逐渐被医学界和兽医界重视的一种人畜共患病，其病原——附红细胞体(Eperythrozoon)是一类无细胞壁、嗜血液寄生的多形态微生物，目前仍被列为立克次氏体目(Rickettisiaies)、无形体科(Anoplasmataceae)、附红细胞体属(Eperythrozoon)。近几年随着对数种附红细胞体的基因序列(16S rRNA)的分析，认为附红细胞体不应属于立克次氏体，宜将其列入柔膜体纲(Mocullicute)的霉形体属(Mycoplasma)。因此，就附红细胞体病的病原分类、形态及生物学特征，以及该病的诊断方法等研究进展作其阐述。     

Judgment under Uncertainty: Heuristics and Biases

This article described three heuristics that are employed in making judgements under uncertainty: (i) representativeness, which is usually employed when people are asked to judge the probability that an object or event A belongs to class or process B; (ii) availability of instances or scenarios, which is often employed when people are asked to assess the frequency of a class or the plausibility of a particular development; and (iii) adjustment from an anchor, which is usually employed in numerical prediction when a relevant value is available. These heuristics are highly economical and usually effective, but they lead to systematic and predictable errors. A better understanding of these heuristics and of the biases to which they lead could improve judgements and decisions in situations of uncertainty.     

Manipulation of the Reconstruction of the Au(111) Surface with the STM

Modification of the reconstruction of an Au(111) surface with a scanning tunneling microscope (STM) is demonstrated. This modification is accomplished by transferring a number of surface atoms to the STM tip to generate a surface multivacancy (hole), which modifies the stress distribution at the surface. The structural changes that follow the tip-induced surface perturbation are imaged in a time-resolved manner. The structural modification is the result of both short-range interactions, which lead to local atomic relaxation, and long-range elastic interactions, which produce large-scale rearrangements.     

曲墙式混凝土衬砌水窖对称面内轮廓线的选形方法

针对传统水窖对大面积集雨需要的局限性,设计了一种曲墙式混凝土衬砌新型水窖,并提出了由集雨量准确确定出其对称面内轮廓线形状的设计计算方法.在设计过程中,根据相关规范确定出该水窖的各个控制点,利用控制点参数建立了水窖对称面内轮廓线的控制方程,最终采用二分法求解出该水窖对称面内轮廓线的形状.算例表明:提出的选形方法可用于实际工程问题的设计计算.对该新型水窖的对称面选形方法的研究,将为今后大面积雨水积蓄设施的设计提供一定的依据.     

Cortical neurons sensitive to combinations of information-bearing elements of biosonar signals in the mustache bat

The auditory cortex of the mustache bat, Pteronotus parnellii rubiginosus, is composed of functional divisions which are differently organized to be suited for processing the elements of its biosonar signal according to their biological significance. Unlike the Doppler-shifted-CF (constant frequency) processing area, the area processing the frequency-modulated components does not show clear tonotopic and amplitopic representations, but consists of several clusters of neurons, each of which is sensitive to a particular combination (or combinations) of information-bearing elements of the biosonar signal and echoes. The response properties of neurons in the major clusters indicate that processing of information carried by the frequency-modulated components of echoes is facilitated by the first harmonic of the emitted biosonar signal. The properties of some of these neurons suggest that they are tuned to a target which has a particular cross-sectional area and which is located at a particular distance.     

玫瑰黄链霉菌Men-myco-93-63有效成分的初步提取与纯化

为了解玫瑰黄链霉菌Men-myco-93-63的代谢产物和其生物活性,对该菌株进行摇瓶培养,从菌丝中提取到一种对棉花黄萎病菌有明显抑制作用的有效成分。经过XAD-1600型大孔吸附树脂,ODS C18硅胶中压柱分离得到黄白色粉末。HPLC检测后,初步断定该物质是一类非常相似的物质组成的混合物,并且极有可能具备互变异构的特性。     

多功能农业创新网络构建与分析

以创新利益为核心,由产业发展、社会管理、环境保护和创新机制等要素构建的多功能农业创新网络,整合了农业发展中的生产性要素与非生产性要素,具有推动新型城镇化发展的作用。以辽宁省大梨树村为例,采用结构方程模型(SEM),分析创新利益与产业发展、社会管理、环境保护和创新机制等要素的关系,探讨多维要素构成的多功能农业创新网络理论框架。结果表明,以生态体验旅游为切入点形成的多功能农业创新网络构建路径,为产业创新发展与土地多样化利用奠定了复合引导机制。社会管理创新是多功能农业网络构建的重要触发力量;产业发展要素与社会管理要素、环境保护要素之间存在的正向作用与反馈关系是创新网络构建的耦合机制。通过实施土地流转政策建立起来的引导机制,促进乡村地区产业发展与社会管理和环境保护的融合创新,丰富新型城镇化的生态文明建设内涵,强化产业发展与生态服务的核心功能,推动多功能农业与乡村地区工业化、城镇化形成协同发展的态势。     

小麦染色体3B和4B雌性育性遗传位点的初选

以普通小麦N8×小麦雌性不育系XND126组合衍生的F2为基本群体,从中选择100株隐性极端不育株构成极端不育群体,以2008-2010年关联分析中的38个SSR阳性关联标记为基本线索进行PCR和电泳实验。与N8带型相同的记为A;与XND126带型相同的记为B;与F1带型即杂合带型相同的记为H。以c=(N1+N2/2)/N计算c值,以c值小于0.4确定标记与位点可能的连锁关系。以初选的c值相对较小的标记为线索,在其参考连锁图上寻找并合成第二批标记引物,再次筛选,共得到3个位于3B染色体上的候选标记Xwmc687(c值为0.360),Xbarc206(c值为0.35)和Xcfb3440(c值为0.375),以及1个位于4B染色体上的候选标记Xgwm495(c值为0.295)。实验结果显示,除本实验室前期定位的小麦雌性育性2DS位点外,3B和4B上可能存在与小麦雌性育性有关的遗传位点。     

高产稳产优质耐旱型水稻新品种金穗1号选育 及旱直播栽培技术

金穗1号是以花培品种“早花2号”为亲本,与优良性状互补的品种杂交配组育成的水稻新品种。既保持了水稻品种高产稳产抗性强品质优的特点,而且抗旱性突出,适合旱直播栽培。冀东旱直播高产栽培的关键在于早播,充分利用当地的气候条件。     

Nanofabrication of Small Copper Clusters on Gold(111) Electrodes by a Scanning Tunneling Microscope

The use of scanning tunneling microscopy in an electrochemical environment as a tool for the nanoscale modification of gold electrodes was demonstrated. Small copper clusters, typically two to four atomic layers in height, were precisely positioned on a gold(111) electrode by a process in which copper was first deposited onto the tip of the scanning tunneling microscope, which then acted as a reservoir from which copper could be transferred to the surface during an appropriate approach of the tip to the surface. Tip approach and position were controlled externally by a microprocessor unit, allowing the fabrication of various patterns, cluster arrays, and "conducting wires" in a very flexible and convenient manner.     

海德格尔对现代技术的批判

海德格尔对现代技术的批判其实是对其生长的根基——传统的形而上学的批判。在海德格尔看来,如果不彻底改变传统的形而上学的主客对立的思维模式,那么任何企图解决技术对我们的拘囚的想法都是肤浅和徒劳的,任何企图在技术内部利用技术来遏制技术的疯狂滋生的做法也是不对的,因为此等做法等于又是用一种存在者来代替另一种存在者。     

关于会计专业实践教学的思考

在强化素质教育与能力培养的时代,如何培养出"高素质、强能力"的应用型复合型人才是教育部门和教育工作者所追求的最终目标.本文从目前会计实践教学现状着手,探讨了如何在会计专业专科课程教学中有效地开展实践教学活动的问题.     

Specificity of Drosophila cytonemes for distinct signaling pathways

Cytonemes are types of filopodia in the Drosophila wing imaginal disc that are proposed to serve as conduits in which morphogen signaling proteins move between producing and target cells. We investigated the specificity of cytonemes that are made by target cells. Cells in wing discs made cytonemes that responded specifically to Decapentaplegic (Dpp) and cells in eye discs made cytonemes that responded specifically to Spitz (the Drosophila epidermal growth factor protein). Tracheal cells had at least two types: one made in response to Branchless (a Drosophila fibroblast growth factor protein, Bnl), to which they segregate the Bnl receptor, and another to which they segregate the Dpp receptor. We conclude that cells can make several types of cytonemes, each of which responds specifically to a signaling pathway by means of the selective presence of a particular signaling protein receptor that has been localized to that cytoneme.     

A fine-scale map of recombination rates and hotspots across the human genome

Genetic maps, which document the way in which recombination rates vary over a genome, are an essential tool for many genetic analyses. We present a high-resolution genetic map of the human genome, based on statistical analyses of genetic variation data, and identify more than 25,000 recombination hotspots, together with motifs and sequence contexts that play a role in hotspot activity. Differences between the behavior of recombination rates over large (megabase) and small (kilobase) scales lead us to suggest a two-stage model for recombination in which hotspots are stochastic features, within a framework in which large-scale rates are constrained.     

浅议图书馆员正确使用计算机与职业健康

从长期使用计算机的图书馆员的常见病种,让读者来了解长期使用计算机带来的严重健康危害,并从人体功效学的角度出发,提出了正确地使用计算机和外部设备的方法,以期预防和减少图书馆员长期使用计算机带来的健康危害。     

基于组合权重的DTOPSIS法在棉品种(系)综合评价中的应用

DTOPSIS法为逼近理想解的排序法,是一种对数据进行综合处理的模型。介绍了其原理和计算方法,并采用组合权重法确定各指标性状权重值,建立了基于信息熵和特尔菲法确定权重的DTOPSIS法决策模型。该模型既考虑了主观因素的影响,又考虑了样本指标体系中所固有的信息的重要性,并通过实例验证了该方法的合理性,为提高棉花品种综合评价的科学性和准确性提供了新思路。     

天目蜜李果实生长发育的研究

天目蜜李果实的生长发育可分为3个阶段:第1阶段从谢花至5月4日,为快速生长期,历时44d,果实纵径与横径分别占成熟果实纵横径的59.48％和48.81％;第2阶段从5月5日至25日,为缓慢生长期,历时21d,果实纵横径分别为成熟果纵横径的11.48％和13.57％,此期为果实硬核期;第3阶段从5月26日至7月1日,为第2次快速生长期,历时35d,果实纵横径分别占成熟果的纵横径的29.07％和37.62％,此期为细胞容积的增大,果实达到最大值。果肉细胞的发育,在果肉不同层次有所差异,以果皮层细胞面积增长最慢。果实生长发育全过程与一般核果类果实发育规律基本相同。为此作者提出了提高天目蜜李产量和质量3条技术措施。