美国休斯基金人才资助模式特征与启示

通过梳理美国霍华德·休斯医学研究所的几种主要人才资助模式，分析其特征，并提出在资助创新研究、培养创新人才、促进科技发展中值得借鉴的发展思路，得到四点启示与建议：要打破项目制的人才培养模式；在评价标准上突出人才的成长潜力；注重对有潜力人才的长周期培养；建立以科研为主的制度约束和保障。     

大气污染优化控制理论的一些新进展

本文介绍了国内学者的最新研究成果，包括了大气污染优化控制理论在以下几个具体应用领域的进展：(1)工业污染源的优化布局。应用伴随方法计算目标函数的梯度以求解优化问题，给出了理论框架。进行了数值试验。(2)短期空气质量的动态控制。应用实际气象数据和污染源数据进行了优化控制数值模拟。(3)化学风险的预先评价与控制。应用伴随方法，对运动化学源进行风险评价。规划最佳运输路线；针对禁止化学武器公约中处理日本二战期间遗弃化学武器的有关问题。妥善选择化武销毁工厂的地址。以上优化控制问题，以气象预报模式和大气污染预报模式为基础，而以伴随方法和最优化算法为求解途径，数值试验表明理论的正确性和方法的高效率。新发展的理论和方法与数值模式和观测技术紧密结合，并且顺应了计算机速度和容量高速增长的趋势。从而具有广阔的应用前景。     

大规模互联网图像检索与模式挖掘

在互联网时代，爆炸式增长的数字图像不仅给图像检索带来巨大的技术挑战，同时也带来了很多机遇和研究问题的新思路．本文简单回顾了图像检索的三个阶段的研究历史．以及在此过程中数据量的增多给图像检索带来的影响，并对作为关键问题的特征提取方面的研究进行了深入的分析．本文尤其指出视觉模式挖掘是寻找中层特征表示并缩小语义鸿沟的重要研究方向，并根据视觉模式的表征粒度将其分为五种类别分别进行了介绍，从中可以看到大数据对于视觉模式挖掘的重要作用．     

基于BT和ABS的公共租赁住房ABT新型融资模式

公共租赁住房作为补充完善住房保障体系，解决“夹心层”住房问题的有力手段，面临着巨大的资金瓶颈。针对公共租赁住房的自身特点，结合BT和ABS模式的特点，提出公租房的新型融资模式——ABT模式。对这种融资模式的产生及运作程序进行分析，并讨论了采用这种融资模式的优势和劣势，提出了运用中应注意的问题。     

遗传算法的模式欺骗性分析

讨论了遗传算法的模式欺骗性和欺骗问题. 描述了模式包含、竞争与关联等概念，给出了基于主竞争关系的模式欺骗性与GA欺骗问题的严格定义，包括完全欺骗问题、一致欺骗问题、序列欺骗问题和基本欺骗问题. 分析了完全欺骗吸引子的特征，给出了形成完全欺骗问题的吸引子应满足的条件. 然后，讨论了GA欺骗性与隐含并行性、收敛性之间的关系. 结合计算实例说明了模式欺骗性对GA搜索行为的影响.     

产业技术跨越模式分析

本文从产业技术跨越概念出现,给出了产业技术跨越的理论模式与实践模式,并结合连城铝厂管理控制自动化的跨越实际,分析了产业技术跨越的实践模式,最后指出了产业技术跨越研究中存在的问题。     

机器命题模式的研究

提出了在对命题题材进行恰当地描述的基础上计算机自动命题的思想；并给出了一种具体的题材描述模型，以及在该模型上基于集合和逻辑运算的机器命题规则，试用结果表明：机器命题是可行的且具有很好的开放性、多样性和实时性。     

县域战略性新兴产业的培育和发展：产业切入、组织保障和路径选择

分析了县域战略性新兴产业培育的制约因素,对县域经济及产业的类型进行了细分。从战略性新兴产业培育的“产业切入”、“组织保障”和“路径选择”三个关键环节,针对县域经济及产业的不同类型,相应提出了战略性新兴产业培育和发展的六种具体模式。并以湘中某县为例进行了分析,为县域战略性新兴产业发展模式的选择提供一种新的参考思路。     

主题乐园游乐服务质量指标及满意度评价研究

我国相当数量的主题乐园生命周期短，对游客重游吸引力低，这与难以找准评估影响主题乐园游乐质量的主要因素，有针对性的改进，吸引顾客重游有很大关系。寻求影响游乐质量的主要因素并用一种合适的模式对其进行评价对主题乐园的理论发展和实际运营都有很好的价值。为此，我们借鉴国内外文献找到评价主题乐园服务质量的指标及评价模式，并以成都国色天乡乐园对国内的主题乐园进行了实证检验。并对实证结果进行了讨论，得出了一些有意义的结论。     

美国科技发展模式特征及对中国的启示

科技发展模式是对国家科技发展的高度概括与总结，选择合理的科技发展模式是实现国家整体发展战略的重要组成部分。本文深入剖析了美国科技发展模式的基本特点及形成条件，为我国制定21世纪的中长期科技发展战略提供了一些的意见与建议。     

Defining motility in the <Emphasis Type="Italic">Staphylococci</Emphasis>

The ability of bacteria to move is critical for their survival in diverse environments and multiple ways have evolved to achieve this. Two forms of motility have recently been described for Staphylococcus aureus, an organism previously considered to be non-motile. One form is called spreading, which is a type of sliding motility and the second form involves comet formation, which has many observable characteristics associated with gliding motility. Darting motility has also been observed in Staphylococcus epidermidis. This review describes how motility is defined and how we distinguish between passive and active motility. We discuss the characteristics of the various forms of Staphylococci motility, the molecular mechanisms involved and the potential future research directions.     

Medium- and short-chain dehydrogenase/reductase gene and protein families

The MDR superfamily with ~350-residue subunits contains the classical liver alcohol dehydrogenase (ADH), quinone reductase, leukotriene B4 dehydrogenase and many more forms. ADH is a dimeric zinc metalloprotein and occurs as five different classes in humans, resulting from gene duplications during vertebrate evolution, the first one traced to ~500 MYA (million years ago) from an ancestral formaldehyde dehydrogenase line. Like many duplications at that time, it correlates with enzymogenesis of new activities, contributing to conditions for emergence of vertebrate land life from osseous fish. The speed of changes correlates with function, as do differential evolutionary patterns in separate segments. Subsequent recognitions now define at least 40 human MDR members in the Uniprot database (corresponding to 25 genes when excluding close homologues), and in all species at least 10888 entries. Overall, variability is large, but like for many dehydrogenases, subdivided into constant and variable forms, corresponding to household and emerging enzyme activities, respectively. This review covers basic facts and describes eight large MDR families and nine smaller families. Combined, they have specific substrates in metabolic pathways, some with wide substrate specificity, and several with little known functions.     

Identifying the conformational state of bi-liganded haemoglobin

While most researchers agree on the global features of cooperative ligand binding to haemoglobin (Hb), the internal mechanisms remain open to debate. This is not due to inaccurate measurements, but is rather a consequence of the cooperative ligand binding that decreases the equilibrium populations of the partially liganded states and makes observation of the transitions between these substates more difficult. For example, the equilibrium population of the doubly liganded tetramers is typically less than 5% of the total Hb. As a result many models with widely varying mechanisms may fit the oxygen equilibrium curve, but may not be consistent with observations of other parameters, such as ligand-binding kinetics or subunit association equilibria. The wide range of methods and models has led to divergent conclusions about the properties of specific substates. One notable debate concerns the properties of the doubly liganded forms. The simple two-state model predicts a shift in the allosteric equilibrium based on the number of ligands bound, but not on their distribution within the tetramer. From studies of dimer-tetramer equilibria of various pure and hybrid forms, it was concluded that a tetramer with two ligands bound on the same α β dimer (species 21, an asymmetric hybrid) shows an enhanced tetramer stability, similar to singly liganded Hb, relative to the other three types of doubly liganded tetramers which resemble the triply liganded forms [Ackers et al. (1992), Science 255: 54–63]. The implications of this model and the relevant experiments will be reviewed here. Received 27 April 1998; received after revision 17 July 1998; accepted 10 August 1998     

Aspects of measurement and analysis of regulatory peptides

Summary Although almost all methods of mass measurement of regulatory peptides still depend on the high affinity antibody, the traditional Yalow and Berson radioimmunoassay technique is becoming outdated. Pure monoclonal antibodies allow excess antibody two site assay techniques with a variety of different labels (preferentially non-radioactive) of great sensitivity and speed. The large amounts of particular monoclonal antibodies available allow several different laboratories to use the same reagents and have increased comparability. Unfortunately many regulatory peptides exist in multiple molecular forms and attention must be paid to antibody region specificity. Improved methods of extraction of regulatory peptides from plasma tissue allow more accurate quantitation. New techniques for rapid high resolution chromatography make distinction of different molecular forms much easier than hitherto. Better education in techniques and/or attention to inter-assay standards are necessary to improve the comparability of regulatory peptide measurement in the future.     

Alkaline phosphatase isozymes in cultured human cancer cells

Summary Alkaline phosphatase, an ubiquitous enzyme is known to exist in several isozymic forms. At least three different isozymes have now been identified in humans. Alkaline phosphatase isozymes are among the substances synthesized ectopically by a variety of human tumors and many continuous cell lines derived from different cancers have retained the capacity to produce these membrane-located glycoproteins. This paper reviews the identification of alkaline phosphatase isozymes in cultured tumor cells and relates these finding with recent developments concerning these cell membrane located glycoproteins.     

Experiential and cosmopolitan knowledge: The transcontinental field practices of the U.S. Bureau of Biological Survey

Before many of the global environmental knowledge producing networks and technologies emerged later in the twentieth century, another spatially extended form of field science was implemented at a continental scale by the U.S. Bureau of Biological Survey, revealing similar tensions and dynamics. Specimens and observations from across continental spaces were integrated through railroad-based transportation and communications networks in order to map distributions of birds and mammals and delineate “life zones” stretching across the continent. At the same time that field zoologists of the Biological Survey produced this cosmopolitan scientific knowledge, they also developed an intimate, experiential knowledge of many of the places where they traveled. By following the travels of Biological Survey field parties, especially the agency's long-time chief field naturalist Vernon Bailey, during the late nineteenth and early twentieth centuries when the railroad was dominant, this paper traces the interconnections between the two ways of knowing in the Biological Survey's practice. However, the integration of these different forms of knowledge was ultimately partial and incomplete, as seen through the Survey's daily practices such as food consumption, the seasonality of survey field practice, and limitations on what types of knowledge were incorporated from lay network collaborators and field assistants.     

The Dim protein family: from structure to splicing

The spliceosome is a dynamic macromolecular machine that catalyzes pre-mRNA splicing through a mechanism controlled by several accessory proteins, including the Dim proteins. The Dim protein family is composed of two classes, Dim1 and Dim2, which share a common thioredoxin-like fold. They were originally identified for their role in cell cycle progression and have been found to interact with Prp6, an essential component of the spliceosome, which forms the bridge of U4/U6.U5-tri-snRNP. In spite of their biological and structural similarities, Dim1 and Dim2 proteins differ in many aspects. Dim1 bears distinctive structural motifs responsible for its interaction with other spliceosome components. Dim2 forms homodimers and contains specific domains required for its interactions with partners. This originality suggests that although both proteins are involved in pre-mRNA splicing, they are likely to be involved in different biological pathways. In the present article we review the structure and function of the Dim proteins.     

Transthyretin: the servant of many masters

Transthyretin (TTR) (formerly, thyroxine binding prealbumin) is an evolutionarily conserved serum and cerebrospinal fluid protein that transports holo-retinol-binding protein and thyroxine. Its serum concentration has been widely used to assess clinical nutritional status. It is also well known that wild-type transthyretin and approximately 100 different mutants give rise to a variety of forms of systemic amyloid deposition. It has been suspected and recently established that TTR can suppress the Alzheimer’s disease phenotype in transgenic animal models of cerebral Aβ deposition. Thus, while TTR is a systemic amyloid precursor, in the brain it seems to have an anti-amyloidogenic effect. TTR is found in other organs as a result of local synthesis or transport, suggesting that it may have other, as yet undiscovered, functions. It is possible that its capacity to bind many classes of compounds allows it to serve as an endogenous detoxifier of molecules with potential pathologic effects.     

Alkaline phosphatase isozymes in cultured human cancer cells

Alkaline phosphatase, an ubiquitous enzyme is known to exist in several isozymic forms. At least three different isozymes have now been identified in humans. Alkaline phosphatase isozymes are among the substances synthesized ectopically by a variety of human tumors and many continuous cell lines derived from different cancers have retained the capacity to produce these membrane-located glycoproteins. This paper reviews the identification of alkaline phosphatase isozymes in cultured tumor cells and relates these findings with recent developments concerning these cell membrane located glycoproteins.