Convexity in projection matrices: Projection to a calibration problem

Convexity, as a fundamental property of sets and functions defined on convex sets, plays an important role in many mathematical and applied disciplines, including extremal and optimal-control problems. We prove the set of all feasible projection matrices in a general class of matrix models for stage-structured population dynamics to be convex and the dominant eigenvalue (λ₁) of any projection 2 × 2 matrix to be either a convex, or a concave function on a simplex of the matrix first-row entries (i.e., stage-specific reproduction rates). The latter is also conjectured for the general n × n case. Though looking far from practical needs of matrix population models, this mathematical result has appeared to be quite useful in solving a practical problem to calibrate the projection matrix, i.e., to estimate all the stage-specific vital rates, from empirical data. The data from monitoring of individual life histories of marked plants on permanent sample plots during successive years enable direct calculation of the stage-specific survival and ontogenetic transition rates, but the rates of reproduction do remain uncertain as far as the parent plants can hardly be determined for the (not yet marked!) recruitment.     

无锡鼋头渚夜鹭卵中有机氯农药残留及其环境指示意义

分析了太湖鼋头渚夜鹭卵中的有机氯农药残留情况,发现在禁用近20年后,HCH的异构体、DDT及其代谢物、异狄氏剂以及环氧七氯在夜鹭卵中都不有同程度的检出,其中β－HCH和p,p‘-DDE的残留水平和检出率均很高,p,p‘-DDE平均达到了0.906ug/g(干重）。研究发现无锡夜鹭卵中多数有机氯农药残留水平平均高于江西共青城地区的样品。无锡夜鹭卵孵化率较低。可能与DDE残留量较高有关。夜鹭卵中有机氯农药残留水平具有指示环境污染的意义。     

The G-Index: a sustainability reporting assessment tool

The subject of sustainability reports, especially those related to GRI, has become an interesting topic to academics and practitioners. This paper seeks to propose an easy-to-use sustainability reporting assessment tool that is suitable to the GRI G4 guidelines. Our idea is to provide a tool that can be applied by an organization, based in GRI indicators, in a quick and easy way. The tool, called G-Index, represents the organizational sustainability performance. The index is a sum of four factors, and a questionnaire about the GRI elements raised the data to elaborate a Mudge diagram, which was used to define the weight values. Finally, the method for the evaluation tool was established, and a case study with the automotive sector was performed. The results showed us the G-Index represents a good option to assess the organization’s disclosure practices in sustainability reports based on the GRI framework. The report analysis presented some important facts, it is more common the disclosure of the Management Approach then the application of External Assurance. Furthermore, even the General Standard Disclosures of the GRI guidelines being mandatory, some companies do not fully disclose them, as shown in the GS factor, that makes up, the G-Index.     

区域环境健康综合风险评价指标体系的构建及应用研究

探讨区域环境健康综合风险评价指标体系建立的原则、思路和方法,估算各省环境健康综合风险,为制定环境健康政策提供科学依据.运用层次分析法,结合主成分分析和独立性分析,按照"风险压力-风险现状-风险应对"的总体思路构建了23个指标的区域环境健康综合风险评价指标体系及其权重系数.运用2012年31个省(自治区、直辖市)的数据进行实证检验,并将评价结果进行聚类分析探讨地区风险的差异和规律.研究表明全国有9个省区域环境健康综合风险指数超过标准,其中特别发达(北京、天津、上海)及不发达地区环境健康综合风险相对较低,较为发达地区环境健康风险较高.区域环境健康综合风险评价指标较为科学合理,具有较好的推广性和实用性.     

Tissue-specific stress and hepatic DNA damage in Pelteobagrus fulvidraco caused by low concentrations of cadmium

Physiological stress and DNA damage in Pelteobagrus fulvidraco induced by continuous exposure to cadmium at concentrations of 170 and 1700 µg/L for up to 28 days was evaluated. The activities of acetylcholinesterase and monoamine oxidase in brain tissue, Na⁺-K⁺-ATPase and glutathione in gill tissue, and superoxide dismutase and catalase in liver tissue were measured. In studying random amplified polymorphic DNA to evaluate cadmium-induced hepatic genotoxicity, both the appearance of new bands and the disappearance of existing bands were observed, as well as increased levels of monoamine oxidase and Na⁺-K⁺-ATPase and decreased activities of antioxidant enzymes. The results suggest that continuous exposure to cadmium at the studied levels can induce biochemical and physiological changes and DNA damage in P. fulvidraco.     

2种茶树对铜胁迫的响应及其组织铜化学形态变化的比较研究

为了分析不同茶树对Cu胁迫的生理响应及其组织中不同化学形态Cu的累积特性,本研究采用水培法,探讨铁观音、肉桂2种茶树在不同浓度Cu胁迫下,茶树根系活力、叶绿素含量、茶树组织Cu含量及不同化学形态Cu含量的变化,以期为重金属对茶树毒害机理和茶树对重金属的自我防御研究提供理论依据。结果表明,随着Cu胁迫浓度的增加,茶树根系活力及叶片叶绿素含量呈现下降趋势,而与对照相比,铁观音下降的幅度远高于肉桂。不同茶树品种在相同浓度Cu胁迫下,其根、茎、叶组织的Cu含量差异不显著,而不同组织中则表现为根叶茎。不同化学形态Cu含量分析结果表明,随着Cu胁迫浓度的升高,2种茶树根部可交换态Cu、碳酸盐结合态Cu、有机结合态Cu含量百分比呈现下降趋势,而铁锰氧化态Cu和残留态Cu呈现上升趋势;茎部可交换态Cu、有机结合态Cu含量百分比呈现下降趋势,碳酸盐结合态Cu、铁锰氧化态Cu和残留态Cu呈现上升趋势;叶部可交换态Cu、碳酸盐结合态Cu、有机结合态Cu含量、铁锰氧化态Cu含量的百分比均呈现上升趋势,而残留态Cu呈现下降趋势。进一步分析发现,Cu胁迫下,铁观音茶树根、叶部主要以采取提高有机结合态Cu的形式来降低Cu离子毒害,而肉桂则以提高铁锰氧化态Cu形式降低Cu离子毒害,叶部则以提高铁锰氧化态Cu和残留态Cu的形式降低Cu离子毒害。可见,不同的茶树在Cu胁迫下所表现解毒模式存在着一定的差异。     

经皮肤暴露四溴双酚A对Wistar雄性大鼠的毒性效应

尘/土以及含阻燃剂产品的皮肤接触是四溴双酚A(TBBPA)重要的人体暴露途径。为研究TBBPA经皮肤亚慢性暴露毒性效应,选择无特定病原菌级别(SPF级)Wistar雄性大鼠作为受试生物,分别设空白对照组(K)、溶剂对照组(Z),以及20mg·kg~(-1)(A)、60 mg·kg~(-1)(B)、200 mg·kg~(-1)(C)、600 mg·kg~(-1)(D)共4个不同剂量的TBBPA暴露组,采用皮肤接触的方式连续暴露90 d。暴露期间观察大鼠状态并称重,于第91天解剖大鼠,分离主要脏器称重计算脏器系数,并对暴露皮肤进行组织病理学检查。研究发现,经皮肤暴露TBBPA后,90 d暴露期间不同实验组Wistar大鼠在表观形态、行动、进食方面无差异,TBBPA暴露导致大鼠体重略微降低,但各处理组间大鼠体重无显著差异;90 d暴露后不同剂量组间大鼠的器官脏器系数没有显著的剂量-效应关系,不同剂量组大鼠皮肤暴露区域均有一定程度的炎症细胞浸润及部分组织胶原间隙增宽。研究结果表明,TBBP A 90 d亚慢性皮肤暴露对Wistar大鼠无明显毒性效应。     

唐山生态城市建设核心指标体系与评价

以我国东部沿海重工业城市—唐山市为例,通过分析其背景及发展特色,应用层次分析法结合专家评价法构建了一套唐山生态城市建设核心指标体系。体系主要包括4类1级指标、13类2级指标和49类3级指标,同时采用线性加权法计算得出唐山生态城市建设过程中不同发展阶段的生态化水平。结果表明,唐山市现阶段已经处于较高的生态化水平;2015年综合指数值可望处于Ⅰ级生态化水平,基本达到生态城市标准;且有望在2020—2030年建成中等发达国家水平的生态化城市。     

锌对汞胁迫下小麦幼苗生理特性的影响

通过沙基培养方法研究不同浓度锌(Zn)对汞(Hg)胁迫下小麦幼苗叶绿素相对含量(SPAD)、丙二醛(MDA)与脯氨酸的积累及抗氧化酶活性等的影响.结果表明:单独Hg(10 mg L-1)胁迫下,小麦幼苗叶绿素含量降低,超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性受到抑制,MDA与脯氨酸含量升高.加入10 mg L-1Zn后,叶绿素含量比Hg单独胁迫升高了5.6%,MDA含量降低了32.4%,表明该浓度Zn在一定程度上缓解了Hg对小麦幼苗的毒害;Zn浓度高于10 mg L-1的处理中,叶绿素含量逐渐降低,MDA则呈升高趋势,表明随Zn浓度升高,Zn对Hg毒害的缓解作用逐渐降低.低浓度Zn(10~20 mg L-1)提高了Hg胁迫下小麦幼苗SOD与CAT活性,其活性随Zn浓度升高逐渐增加,20mg L-1Zn处理下,两种酶活性比Hg单独胁迫分别升高了103.3%与71.0%,高浓度Zn(50~100 mg L-1)处理下,两种酶活性则呈下降趋势,表明Zn对Hg胁迫下两种酶活性的促进作用逐渐减弱.在试验设置的Zn浓度范围内,脯氨酸含量均低于Hg单独胁迫,并且低于对照,说明外加Zn抑制了脯氨酸的生成.综上所述,10~20 mg L-1的Zn可以在一定程度上缓解10 mg L-1Hg对小麦幼苗造成的毒害.     

The nature of safety culture: a review of theory and research

This paper reviews the literature on safety culture and safety climate. The main emphasis is on applied research customary in the social psychological or organisational psychological traditions. Although safety culture and climate are generally acknowledged to be important concepts, not much consensus has been reached on the cause, the content and the consequences of safety culture and climate in the past 20 years. Moreover, there is an overall lack of models specifying either the relationship of both concepts with safety and risk management or with safety performance. In this paper, safety culture and climate will be differentiated according to a general framework based on work by Schein (1992 Schein) on organisational culture. This framework distinguishes three levels at which organisational culture can be studied — basis assumptions, espoused values and artefacts. At the level of espoused values we find attitudes, which are equated with safety climate. The basic assumptions, however, form the core of the culture. It is argued that these basic assumptions do not have to be specifically about safety, although it is considered a good sign if they are. It is concluded that safety climate might be considered an alternative safety performance indicator and that research should focus on its scientific validity. More important, however, is the assessment of an organisation's basic assumptions, since these are assumed to be explanatory to its attitudes.