Does diversity damage corporate value? Measuring stock price reactions to a diversity award

Corporate decision-makers have increasingly adopted an approach to firm governance that places share value above other concerns, including meeting the needs of employees. Decision-makers' concerns about shareholder interests may potentially impede internal commitments to implementing diversity-friendly practices and policies. This study analyses how recognition for a company's diversity efforts impacts corporate share price. We rely on data of share price fluctuation following the receipt of Fortune Magazine's ‘Best Companies for Minorities’ Award. We find that companies recognized for their diversity efforts are penalized with a significant decline in share price, though this negative effect is mediated by the ethnic composition of the company's workforce.     

ST-segment elevation associated with allergic reaction to echocardiographic contrast agent administration

We report a case of an allergic reaction after the administration of an echocardiographic contrast agent which resulted in ST-segment elevation. Hypersensitivity and allergic reactions are known causes of acute cardiovascular events. However, only limited reports are available which suggest the exact mechanism of the occurrence of angina or myocardial infarction during severe allergic reactions. In our case, through invasive imaging (coronary angiography and IVUS) we have shown for the first time a transient coronary spasm in the absence of intra-coronary thrombus and only minimal neointimal hyperplasia.     

Influence of weather on emergency transport events coded as stroke: population-based study in Japan

Studying the relation between incidence of stroke and weather is difficult because it requires large-scale community-based data collection. Despite the lack of strong evidence that weather conditions influence stroke incidence, many clinicians feel that meteorological conditions influence the onset of stroke. This study examined whether emergency events related to stroke are influenced by meteorological factors and was based on computerized records of emergency medical transport services in a Japanese city during the period January 1992–December 2003. A total of 53,585 patients transported for an event coded as stroke were analyzed in relation to meteorological factors such as temperature, humidity, and barometric pressure. Poisson regression analysis was applied to clarify the influence of daily meteorological conditions on the daily incidence of emergency transport due to events coded as stroke. Ordinary least squares regression analysis was used to evaluate the influence of weather, defined as the combination of meteorological parameters, on the occurrence of emergency transport due to events coded as stroke. Daily mean ambient temperature and daily mean relative humidity showed a statistically significant negative effect on the incidence of the emergency transport events for both men and women (P<0.001). Daily mean barometric pressure was not significantly related to these events. The occurrence of a holiday was negatively related to the incidence (P<0.001). Dry weather and cool weather were likely to shift the circadian curve of the incidence upward. Thus, occurrence of emergency transport due to events coded as stroke is likely to be associated with weather conditions.     

生物多样性不同层次尺度效应及其耦合关系研究进展

生物多样性包含遗传、物种、生态系统和景观多样性4个层次,虽然各个层次的研究较多,但是各层次间相互关系的研究较少。物种多样性多采用野外样方调查法,景观多样性采用遥感、地理信息系统和野外调查,研究方法较为成熟;生态系统多样性研究因生物地理地域和尺度的不同,常采用不同的分类体系,尚无统一评估标准。物种多样性的尺度效应在α、β、γ指数上均有不同体现,景观多样性的尺度效应非常明显。生境异质性与物种α和β多样性指数密切相关,在一定尺度上,丰富的景观多样性提高了物种多样性。未来研究需要揭示不同生物多样性层次之间的耦合关系,并将研究结果应用到生态系统红色名录制定、区域生物多样性综合监测与评估等实践之中。     

蝗虫肠道微生物研究进展

蝗虫自古以来是我国农林牧业的一大害虫,蝗虫聚集成灾对农业造成了巨大的损失,国内外学者也因此对其进行了深入的研究。随着科研工作者对昆虫肠道微生态学理论的逐渐重视,蝗虫的肠道微生物也成为了研究的重点,同时测序技术的迅速发展促进了蝗虫肠道微生物的研究。本文从蝗虫肠道菌群的多样性、功能及研究方法入手,对近年来蝗虫肠道微生物的研究进展进行总结,并对今后的研究进行展望。     

Effects of a recent founding event and intrinsic population dynamics on genetic diversity in an ungulate population

Maintenance of genetic diversity has recently become a management goal for a number of species, due to its importance for present and future population viability. Genetic drift, primarily through differential reproductive success and inbreeding, can accelerate the loss of genetic diversity in recently recovered populations. We attempt to quantify the consequences of these factors on the genetic diversity contained in a small, recently founded wood bison (Bison bison athabascae) population by examining the genetic variation in this conservation herd, the calves born therein, and its large source population. The Hook Lake Wood Bison Recovery Project was initiated to found a disease-free herd of wood bison containing a representative amount of the genetic diversity present in the Wood Buffalo National Park metapopulation. Levels of diversity in the Hook Lake Wood Bison Recovery Project founders are higher than in previous salvage attempts. To examine the effects of differential reproductive success on this population, we monitored parentage of the calves born in the Hook Lake Wood Bison Recovery Project for 3 years since the founders reached sexual maturity. Two of the male founders sired over 90% of the offspring born in this population, which has led to a reduction in diversity in their calves. Monitoring of reproductive success, and incorporation of selective breeding strategies will be required to reduce the rate at which genetic diversity is lost from this small, isolated population. These steps should occur in other recovery projects, particularly when a small number of individuals are capable of dominating reproduction.     

柱花草RAPD反应体系的建立及其8个品种遗传多样性分析

采用两种不同的方法分别从柱花草嫩叶及种子萌发芽中提取了高质量的DNA ,并对柱花草RAPD反应中的各组分浓度及热循环因素进行优化 ,建立了柱花草RAPD反应的最佳条件。在此基础上 ,用 2 0条随机引物对 8个柱花草品种进行了RAPD扩增 ,结果表明 ,其多样性达 5 1 .9% ,品种间的遗传相似系数在 0 .5 3～0 .88之间 ;根据非加权成对平均数法 (UPGMA)进行分类 ,获得了品种聚类树形图 ,8个柱花草品种均被明显分开。     

贵州茂兰自然保护区蜻蜓多样性初步研究

2011年7月在贵州茂兰自然保护区的一些比较适合蜻蜓生长的水域附近进行了蜻蜓采集,用静观和网捕法记录采集路线两侧各20m范围内的蜻蜓,鉴定统计后分析其区系成分及多样性.结果表明:1)贵州茂兰地区现有蜻蜓65种,隶属于11科42属;2)东洋界种类较多,有31种,占总数的47.69％;古北界种类相对较少,只有1种,约占总数的1.54％;3)贵州茂兰地区蜻蜓的多样性指数为2.8617,均匀度指数为0.6855,优势度指数为0.1385,优势集中性指数为0.1006;4)5个样点之间的相似性指数均在30％ ～55％之间,且只有捞村与翁昂为53.41％,捞村52.77％大于板王50％,这可能与茂兰地区生境的多样性相对较高,适宜蜻蜓生存的生境多有关.     

Efficient Electrophilic Fluorination for the Synthesis of Novel 2′-Fluoro-3′-Methyl-5′-Deoxyphosphonic Acid Apiosyl Nucleoside Analogues

Novel 5′-deoxyapiosyl purine phosphonic acid analogues with a 2′-electropositive moiety, such as, a fluorine atom were designed and synthesized from commercially available hydroxylacetone. Condensation of a glycosyl donor 10 with purines under Vorbruggen conditions and cross-metathesis give the desired nucleoside phosphonic acid analogues 14, 17, 21, and 24. The synthesized nucleoside analogues were subjected to antiviral screening against HIV-1, and the adenine analogue 17 exhibited weak in vitro anti-HIV-1 activity (EC₅₀ = 26.6 μM)     

High-resolution analysis of Y-chromosomal polymorphisms reveals signatures of population movements from central Asia and West Asia into India

Linguistic evidence suggests that West Asia and Central Asia have been the two major geographical sources of genes in the contemporary Indian gene pool. To test the nature and extent of similarities in the gene pools of these regions we have collected DNA samples from four ethnic populations of northern India, and have screened these samples for a set of 18 Y-chromosome polymorphic markers (12 unique event polymorphisms and six short tandem repeats). These data from Indian populations have been analysed in conjunction with published data from several West Asian and Central Asian populations. Our analyses have revealed traces of population movement from Central Asia and West Asia into India. Two haplogroups, HG-3 and HG-9, which are known to have arisen in the Central Asian region, are found in reasonably high frequencies (41.7% and 14.3% respectively) in the study populations. The ages estimated for these two haplogroups are less in the Indian populations than those estimated from data on Middle Eastern populations. A neighbour-joining tree based on Y-haplogroup frequencies shows that the North Indians are genetically placed between the West Asian and Central Asian populations. This is consistent with gene flow from West Asia and Central Asia into India.     

皮下盘菌属种内及种间遗传多样性的ISSR分子标记

对皮下盘菌属（Hypoderma）4种23个菌株进行了ISSR分析。结果表明,被试材料ISSR标记多态性好,8个引物共扩增出131个条带,其中126条（占9618％）具有多态性。经欧氏最短距离中的类平均法聚类,得到各菌株之间的ISSR标记的遗传相似性系数（GS）变异范围为0．30—0．82,23个菌株可聚为6类。通过ISSR分析结果与表型性状的比较和分析,明确了悬钩子皮下盘菌种内遗传差异体现在子囊果大小、形状及埋生深度、唇特征、侧丝顶端形状、子囊和子囊孢子形状及大小,以及寄主、着生部位和分布区域方面;皮下盘菌属的种间差异主要表现在子囊果、唇、侧丝、子囊及分生孢子器等部分形态学特征、寄主及着生部位方面。     

淡水鱼类功能多样性及其研究方法

目前,群落功能多样性备受生态学界关注,被认为是能解决生态问题的一种重要途径。我国对于群落功能多样性主要集中在植物群落和微生物群落,而在鱼类群落方面的研究几乎是空白。我国鱼类资源正面临着严重威胁,包括水坝建设导致的鱼类通道受阻、水库形成造成鱼类产卵场功能消失、过度捕捞、水质恶化和富营养化加重、外来种入侵等因素,导致渔业资源急剧衰退,水生生态系统功能下降。以淡水鱼类群落为例,对鱼类功能多样性的数据获取及处理分析与评价、测定指标及计算方法与研究难点等进行综述,以期为鱼类资源保护提供新的理论依据和切入点。