Poly-3-Hydroxyalkanoates containing unsaturated repeating units produced by pseudomonas oleovorans

Poly-3-hydroxyalkanoates (PHAs) containing repeating units with terminal alkene substituents at the 3-position were produced by Pseudomonas oleovorans grown with either 7-octeneoic acid [OA(?)] alone, or 10-undeceneoic acid [UND(?)] alone, or mixtures of UND(?) and either nonanoic acid (NA) or octanoic acid (OA). For the latter, the biomass and PHA yields decreased as the fraction of UND(?) increased in the mixed carbon substrates. Essentially all of the repeating units in the PHA obtained from cells grown with UND(?) alone contained terminal alkene groups, including 3-hydroxy-10-undeceneoate, 3-hydroxy-8-noneneoate, and 3-hydroxy-6-hepteneoate units, but less than half of the units in the PHA from OA(?) had alkene substituents. The PHAs obtained from cells grown with various mixtures of UND(?) and either OA or NA were random copolymers, and the fraction of units with alkene substituents in these polymers increased in proportion to the fraction of UND(?) in the mixed carbon substrates. © 1995 John Wiley & Sons, Inc.     

艾比湖湿地自然保护区土壤盐分多光谱遥感反演模型

土壤盐分是衡量土壤质量的要素,也是作物生长发育的基本条件。因此,迫切地需要一种可以快速了解土壤盐分含量（SSC）的方法。针对艾比湖湿地自然保护区,基于Landsat8 OLI多光谱遥感影像,以该研究区36个土壤表层样品的盐分含量为数据源,选择相关性较好的多光谱遥感指数分析研究区土壤盐分分布状况,并将其分别与实测SSC构建线性、对数、二次函数模型,进而优选精度最高的模型来反演该研究区SSC。结果表明：（1）在多光谱遥感指数中,与SSC相关性最高的是增强型植被指数（EVI）,其相关性范围为（-0.70~-0.67）;其次是传统型植被指数（TVI）,其范围为（-0.58~-0.46）;土壤盐分指数（SI）与SSC的相关性最低,其范围为（-0.45~0.16）,其中SI3和SI4与SSC均没有相关性。（2）将实测土壤盐分值所反演的分布图与EVI对比分析,发现在西北、正南方向的艾比湖湖边周围和东北方向盐池桥的SSC均较高,其EVI的值较低,说明通过该研究区实测土壤盐分值所反演的盐分分布图与EVI的空间分布结果较为一致,表明EVI对该地区土壤盐分具有一定的敏感性,能较好地反演SSC的空间分布;（3）分别将三种EVI与实测SSC建模分析比较,发现SSC与增强型比值植被指数（ERVI）所构建的二次函数模型最好;其验证集的决定系数（R2）为0.92,均方根误差（RMSE）为2.48,相对分析误差（RPD）为2.09,模型精度较高、稳定性较为可靠,相比之下,说明ERVI对该湿地自然保护区土壤盐分有更高的敏感性,可以用来预测该区域SSC,从而进行空间反演。在TVI中加入Landsat8多光谱遥感影像的b6和b7波段,得到EVI,以此来反演SSC是可行的,且比传统可见光和近红外波段所构建的植被指数反演效果更好。因此该研究不仅可以为遥感反演提供理论参考,而且对该地区SSC的定量估算和动态监测具有重要的意义,也可作为其他区域SSC预测反演的备选方案。     

中学生英才计划的“进阶式培养”模式

The "Senior High School Students Elite Program" is a training program developed by the state to train top-notch talents for scientific and technological innovation. This paper summarized the training situation of elite students in the past three years, and put forward a progression education mode. We hope that this education mode will truly benefit those senior high school students who have a strong interest in scientific research, so that the "Senior High School Students Elite Program" can be developed well and provide reference significance to realize its original intention.     

Water-Based Aerosol for Book Deacidification: Experimental Apparatus and Theoretical Interpretation of Results

One of the major problems in book conservation is the long-term deconstructive effect of acidity introduced into the paper by several additives, which, in the presence of humidity, generates a hydrogen cation with a strong catalytic role in cellulose depolymerization. Many types of treatment have been used in the past, but up to now, research for less-invasive, fast and cheap methods is still vividly ongoing. In this study, an approach to book deacidification is presented, where alkaline water solutions are administered to bound books in the form of micrometer-sized aerosol droplets, without using vacuum apparatus accessories. Alkaline clouds treatments were alternated with gentle air fluxes of drying steps. Few cycles are required to achieve uniform deacidification of books. The treatment could be conducted with proper apparatus on large volumes, resulting in rapid treatment time and low cost. The titration curve reporting the variation of book pH, with respect to the amount of absorbed alkaline aerosol, was built and interpreted in terms of a chemical model for the neutralization process. FTIR, PXRD and XRF spectroscopies were used to characterize the book chemistry. The effects of the treatment on the book were evaluated by measuring the degree of polymerization (DP) of the paper and the colorimetric coordinates of the paper and ink. Artificial aging tests revealed a general increase in the aging stability of the deacidified paper samples with respect to the untreated samples. Finally, the alkaline reserve data are discussed.     

凤阳山自然保护区鸟类调查

本文记录了1980年春夏季和冬季对凤阳山自然保护区鸟调查的74种鸟,隶属于10目24科,其中14种为本省当时的新记录,留鸟占总数的70％;东洋界种类占63.5％。区系组成上具有华南区的特色。 以大田坪(1220米)和夏边(650米)两地为调查点。两地春夏季鸟类的群体密度无显著性差异,大田坪的多样性指数(H′)高而群落的优势度指数(C)小;冬季两地的群体密度具极显著差异,夏边的H′值高而C值小。 此外,在春夏季观察了鸟类的繁殖活动并记述了采到的五种鸟巢及内容。     

Some new notions of dependence with applications in optimal allocation problems

Dependence structures of multiple risks play an important role in optimal allocation problems for insurance, quantitative risk management, and finance. However, in many existing studies on these problems, risks or losses are often assumed to be independent or comonotonic or exchangeable. In this paper, we propose several new notions of dependence to model dependent risks and give their characterizations through the probability measures or distributions of the risks or through the expectations of the transformed risks. These characterizations are related to the properties of arrangement increasing functions and the proposed notions of dependence incorporate many typical dependence structures studied in the literature for optimal allocation problems. We also develop the properties of these dependence structures. We illustrate the applications of these notions in the optimal allocation problems of deductibles and policy limits and in capital reserves problems. These applications extend many existing researches to more general dependent risks.     

考虑情绪波动的关联价值拍卖模型研究

将考虑参考点的效用函数引入关联私人价值拍卖模型,证明了在APV中,竞拍人整体情绪的波动不会改变卖方对拍卖方式的选择,推广了最优拍卖价的相关研究结论;用数值运算的方法说明了在独立私人价值模型中,竞拍人整体情绪的波动可能引起最优保留价的较大波动,而在考虑关联性的私人价值模型中,竞拍人整体情绪的波动可能导致最优保留价的跳跃行为.     

基于有限服务排队系统的未决赔款准备金分布

若保险赔付工作中赔付人员有限,根据服务人员有限的排队系统的性质,可以研究保险公司所需计提的未决赔款准备金的分布函数.当假设赔付服务工作人员为c个,使用M/M/c/∞和G/M/c/∞排队系统的性质可以得到未决赔款准备金分布函数和年末所需增加计提的未决赔款准备金的分布及其界值.当假设赔付服务工作人员仅一个,使用M/G/1/∞排队系统的性质可以得到此时未决赔款准备金的分布函数.并且在假设损失赔付额取正整数的条件下,得到年末保险公司所需增加计提的未决赔款准备金分布的递推公式.而且通过计算实例表明结论的实用性,及所得到的递推公式在以往难以准确求解未决赔款准备金分布时是十分有效的.     

Mathematical optimization ideas for biodiversity conservation

Several major environmental issues like biodiversity loss and climate change currently concern the international community. These topics that are related to the development of human societies have become increasingly important since the United Nations Conference on Environment and Development (UNCED) or Earth Summit in Rio de Janeiro in 1992. In this article, we are interested in the first issue. We present here many examples of the help that using mathematical programming can provide to decision-makers in the protection of biodiversity. The examples we have chosen concern the selection of nature reserves, the control of adverse effects caused by landscape fragmentation, including the creation or restoration of biological corridors, the ecological exploitation of forests, the control of invasive species, and the maintenance of genetic diversity. Most of the presented models are – or can be approximated with – linear-, quadratic- or fractional-integer formulations and emphasize spatial aspects of conservation planning. Many of them represent decisions taken in a static context but temporal dimension is also considered. The problems presented are generally difficult combinatorial optimization problems, some are well solved and others less well. Research is still needed to progress in solving them in order to deal with real instances satisfactorily. Moreover, relations between researchers and practitioners have to be strengthened. Furthermore, many recent achievements in the field of robust optimization could probably be successfully used for biodiversity protection, a domain in which many data are uncertain.     

市场化改革、经济战略与中国外汇储备积累:实证研究

对中国外汇储备成因的传统研究在很大程度上忽略了市场化进程因素对中国外汇储备积累的历史性和制度化影响。而外汇储备的决定因素分为两大类:战略性因素和制度性因素。战略性因素包括预防性需求、重商主义动机和机会成本;制度性因素包括对外贸易发展和市场化程度。通过一个改进的外汇储备需求函数模型对该因素进行实证研究,发现中国的外汇储备积累主要是外向型经济发展模式和市场化改革这一历史进程的客观结果,而非货币当局基于主观动机所追求的战略目标。