Effects of Bacillus thuringiensis var. israelensis on Target and Nontarget Organisms: a Review of Laboratory and Field Experiments

Since the discovery of Bacillus thuringiensis var. israelensis (Bti) in 1976, extensive literature has proved its efficacy to control mosquitoes and black flies, of which many species are known as important vectors of diseases or simply as pests of humans and animals. Since 1978, Bti has been used in many countries on all continents and numerous studies have been made on target mosquitoes and black flies, as well as nontarget organisms (NTO). This review analyses the results of 75 studies on these organisms covering approximately 125 families, 300 genera and 400 species. Different factors such as species, instar, feeding behaviour and environmental parameters (larval density, water temperature, suspended matter etc.) may drastically affect the efficacy of the Bti products. This is addressed in detail by reviewing the main factors affecting mosquitoes as well as black flies. The results of a wide range of laboratory and field experiments using different target and nontarget species, various preparations and formulations of Bti and different biotic or abiotic factors are present in the literature, making the data difficult to compare on a common basis. Our analysis shows that, under different application conditions, the effects of Bti on target and nontarget organisms may be hard to predict. Although Bti has been proclaimed to be relatively highly specific, some studies show that some NTO are affected either by single or repeated Bti treatments. Present use against black flies seems ecologically acceptable. High frequencies of application and/or overdosages against mosquitoes may result in some persistence of the toxin crystals and ultimately this may have adverse effects on the food web. A long-term study (published in 1998) in mosquito habitats has shown that intensive Bti treatments over three years did in fact produce an impact on the food web in wetlands. This raises questions, for the first time, on Bti environmental specificity. The importance of this impact is discussed and the alternatives for practical pest control are considered. Some modifications of Bti use against mosquitoes, guided by research, is probably the best of these alternatives.     

Effects of water-level fluctuations on lakes: an annotated bibliography

Water-level fluctuations (WLF) in lakes and rivers, especially their extent, frequency and duration, are dominant forces controlling the functioning of these ecosystems. In particular, WLF play an important role in the lake’s littoral and aquatic–terrestrial interface processes. WLF may take place on different spatial and temporal scales under natural conditions but water levels have been artificially modified in regulated lakes, and their impacts are expected to be enhanced within the actual global change scenarios with forthcoming management problems. This article presents an overview on the literature published on this important topic since 1991 by using journals indexed in the ISI Web of Knowledge. The overall objective was to examine temporal and spatial trends in publications on WLF, the specific aspect of WLF concerned and their main effects. Throughout the article we have used case studies to illustrate different effects of WLF on the variety of lake habitats and indicators that have been studied. Overall, the number of papers published on the subject since the 1990s has risen steadily, when less than ten papers were published each year; until 2006 and peaking in 2005. The greatest number of papers on WLF has been carried out in Europe and North America (c. 73%). These data also showed that the effects of WLF have not been studied equally for different groups of organisms. There is a greater interest on macrophytes, which are the most studied group of organisms (18.4% of the papers). Nearly 7% of the papers deal with algae, and zooplankton and invertebrates account for a 7% followed by fish. WLF effects on ecosystems are very complex, and the biological effects in lakes are greatest in shallow water and littoral areas, where even small changes in water levels can result in the conversion of large areas of a standing-water environment in air exposed habitats. Finally, these data might serve to highlight knowledge gaps still existing on this topic and, in particular, some of the approaches that can potentially contribute to solve several of these lacunae are explored.     

基于Web of Science数据库扩张型心肌病研究的文献计量学分析

目的:对扩张型心肌病(Dilated Cardiomyopathy,DCM)的研究,目前仍是国际上对于原发性心肌病研究的热点问题。本文针对DCM相关领域的研究文献进行计量分析,从而进一步深入了解国际DCM研究进展,为该研究的相关领域提供参考。方法:基于(SCIE)引文数据库为检索对象,检索2003-2012年DCM的所有相关文献,分别对不同国家和地区、著者、机构、文献来源期刊及论文学科分布等进行统计分析。结果:共检索出DCM研究文献12728篇,研究论文发表共涉及了107个国家和地区,美国的发文数最多4500篇,占35.36%,其次为德国和日本。中国居第9位,504篇占总发文量的3.96%;主要刊登期刊涵盖了国际上心血管领域的15种知名期刊;研究热点涉及心血管系统及脏病学、分子生物学、基因遗传学等学科。结论:目前DCM研究仍是人们关注的一个热点,美国、德国、日本等发达国家在该领域的研究居领先水平,中国在这一领域也做出了贡献。与领先国家和机构相比,我国亟需进一步加强对DCM的研究。为我国进一步了解和深入研究DCM的方向提出参考。     

肿瘤学生物信息资源检索及其应用

肿瘤尤其是恶性肿瘤的诊断与治疗是目前医学界讨论最多的问题,同时肿瘤学也是生物医学界投入人力物力最多的研究领域.迄今为止,肿瘤在病因和发病机制上尚无突破性的进展,但已经掌握了大量的基础和临床肿瘤学资料,这些海量的肿瘤信息资源中必然蕴含着重要的信息,如何把所需的有用信息找寻出来,应用到临床、教学和科研实践中,成为目前迫切需要掌握的课题.     

Parallel Analysis: a method for determining significant principal components

Abstract. Numerous ecological studies use Principal Components Analysis (PCA) for exploratory analysis and data reduction. Determination of the number of components to retain is the most crucial problem confronting the researcher when using PCA. An incorrect choice may lead to the underextraction of components, but commonly results in overextraction. Of several methods proposed to determine the significance of principal components, Parallel Analysis (PA) has proven consistently accurate in determining the threshold for significant components, variable loadings, and analytical statistics when decomposing a correlation matrix. In this procedure, eigenvalues from a data set prior to rotation are compared with those from a matrix of random values of the same dimensionality (p variables and n samples). PCA eigenvalues from the data greater than PA eigenvalues from the corresponding random data can be retained. All components with eigenvalues below this threshold value should be considered spurious. We illustrate Parallel Analysis on an environmental data set. We reviewed all articles utilizing PCA or Factor Analysis (FA) from 1987 to 1993 from Ecology, Ecological Monographs, Journal of Vegetation Science and Journal of Ecology. Analyses were first separated into those PCA which decomposed a correlation matrix and those PCA which decomposed a covariance matrix. Parallel Analysis (PA) was applied for each PCA/FA found in the literature. Of 39 analy ses (in 22 articles), 29 (74.4 %) considered no threshold rule, presumably retaining interpretable components. According to the PA results, 26 (66.7 %) overextracted components. This overextraction may have resulted in potentially misleading interpretation of spurious components. It is suggested that the routine use of PA in multivariate ordination will increase confidence in the results and reduce the subjective interpretation of supposedly objective methods.     

A combined strategy of “in silico” transcriptome analysis and web search engine optimization allows an agile identification of reference genes suitable for normalization in gene expression studies

Traditionally housekeeping genes have been employed as endogenous reference (internal control) genes for normalization in gene expression studies. Since the utilization of single housekeepers cannot assure an unbiased result, new normalization methods involving multiple housekeeping genes and normalizing using their mean expression have been recently proposed. Moreover, since a gold standard gene suitable for every experimental condition does not exist, it is also necessary to validate the expression stability of every putative control gene on the specific requirements of the planned experiment. As a consequence, finding a good set of reference genes is for sure a non-trivial problem requiring quite a lot of lab-based experimental testing. In this work we identified novel candidate barley reference genes suitable for normalization in gene expression studies. An advanced web search approach aimed to collect, from publicly available web resources, the most interesting information regarding the expression profiling of candidate housekeepers on a specific experimental basis has been set up and applied, as an example, on stress conditions. A complementary lab-based analysis has been carried out to verify the expression profile of the selected genes in different tissues and during heat shock response. This combined dry/wet approach can be applied to any species and physiological condition of interest and can be considered very helpful to identify putative reference genes to be shortlisted every time a new experimental design has to be set up.     

The Concept of Attributable Risk in Epidemiological Practice

Different epidemiological parameters have been suggested for the quanitification of the impact of an exposure factor on the burden of morbidity of a population, termed “attributable risk”. Of these definitions, the “AR” as introduced by Levin (1953), including some transformations, is most commonly used. A structured search of the Medline ^TM database for publications dealing with this AR (1966 to 1996) identified 334 such original studies (mostly case control studies) and meta analyses, with a considerable increase during the last decade. Mostly, no precise reference was made to the definition of AR employed (64.5%). Adjustment procedures were performed in only 37.5% of studies, confidence intervals for point estimates of AR were calculated by only 19.3% of authors. Thus, in view of an encouraging popularity of this important public health parameter, the correct application of AR should be promoted further.     

Ecosystem disservices research: A review of the state of the art with a focus on cities

Ecosystem services, the benefits produced by ecosystem functions and structures for human well-being, have received continuous international attention since the publication of the Millennium Ecosystem Assessment (MA) and the TEEB study (The Economics of Ecosystem Services and Biodiversity). Ecosystem functions also have effects that are harmful to human well-being, and these effects are called ecosystem disservices (EDS). The aim of this paper is to explore how ecosystem disservices have been recognised in the scientific literature and how the concept has been used in the discussion of socio-ecological systems. The paper analyses 103 studies on EDS. We use a quantitative approach to assess geographical spread, focus and indicator choice. This quantitative picture is supplemented by a qualitative discussion of the effects of ecosystem disservices on urban systems and cities. The results of the review show that although the idea of detrimental ecosystem effects is not new, systematic research on EDS has only just begun. Most studies on EDS focus on Western Europe or the USA. EDS have been more frequently discussed in the most human-dominated ecosystem types: i.e., in agricultural and urban ecosystems. The latter in particular will be central for future research on EDS, considering that more than 75% of the world's population is expected to live in urban environments by 2050.     

Systematic conservation planning: Trends and patterns among highly-cited papers

Systematic conservation planning (SCP) is a field of conservation biology concerned with the effective allocation of conservation efforts and the implementation of actions aiming to guarantee biodiversity persistence in the long-term and the efficient use of conservation resources. Here, we evaluated the main spatial-temporal trends and patterns among highly-cited papers in SCP. We considered “highly-cited” articles as those papers with at least 100 citations according to Web of Science database. A total of 132 highly-cited articles were published between 1989 and 2014, with the highest frequency at 2006. Papers were published in 25 different scientific journals (with a highlight for Conservation Biology and Biological Conservation) by researchers from 208 institutions and 25 countries (most from Australia and USA). Most of the analytical and methodological studies were carried out in the terrestrial environment, by considering more than one taxonomic group, and at a regional scale. Eleven studies included information on costs (e.g., economic or land use) in the prioritization process, and only one article considered information on other biodiversity dimensions such as phylogenetic diversity. Among analytical papers, 41 included only biodiversity data in the prioritization process, while 16 papers considered data on other features such as ecosystem services, biophysical factors, and vegetation. Furthermore, a plethora of different algorithms and software were used to perform the analyses. By analyzing the top-cited papers, we could track through time the main advances and stages of the development in SCP.     

基于微信公众平台的文献定制服务

文献学习是科研人员跟踪领域进展,思考课题发展的必要途径。为了解决移动端跟踪文献的繁琐问题,本文借助移动互联网即时性、便捷性、个性化等特性,开发了基于微信公众平台的文献定制服务。该服务通过解析用户输入,动态匹配自构建的期刊名表,索引Pub Med数据库,实现期刊个性化订阅、文献查询、影响因子查询等便捷功能。对于提高科研人员的文献学习效率,降低追踪文献的时间成本具有较大的价值。