Extinction debt in fragmented grasslands: paid or not?

Fragmentation of grasslands and forests is considered a major threat to biodiversity. In the case of plants, the effect of fragmentation or landscape context is still unclear and published results are divergent. One explanation for this divergence is the slow response of long‐lived plants, creating an extinction debt. However, this has not been empirically confirmed. In this study, data were compiled from broad‐scale studies of grasslands from throughout the world that relate plant diversity to fragmentation effects. Only seven studies from northern Europe, out of a total 61, gave any information on actual habitat fragmentation in time and space. In landscapes with >10% grassland remaining, present‐day species richness was related to past landscape or habitat pattern. In landscapes with <10% grassland remaining, in contrast, plant species richness was more related to contemporary landscape or habitat pattern. Studies from landscapes with >10% grassland remaining supported the concept of an extinction debt, while studies from more fragmented landscapes did not provide any evidence of an extinction debt. In order to make generalisations about historical legacies on species diversity in grasslands it is important to consider a range of highly transformed landscapes, and not only landscapes with a high amount of grassland remaining.     

Studying the impact of the Eurozone’s Great Recession on health: Methodological choices and challenges

Europe’s Great Recession provides an opportunity to study the impact of increased financial insecurity on health. A number of studies explored the impact of the Recession on health, but they often reached different conclusions. To understand the root of this debate, we undertook a systematic literature review. Articles were analysed thematically based on: geography, data type, operationalisations of wealth and health, and study design. A critical appraisal was also undertaken. Forty-two studies, published from January 2010 to October 2018, were included in our review. Twenty-six of the forty-two studies found that the Great Recession worsened physical health indicators in the Eurozone. In terms of geography, a large concentration of studies focussed on Spain and Greece, indicating that there may be a gap in understanding the health consequences for EU countries with less severe experiences of the Recession. Regarding data type, nearly all studies used secondary datasets, possibly meaning that studies were constrained by the data available. In terms of operationalisations of wealth and health, a majority of studies used single/simple measures of both, so that these multi-faceted concepts were not fully reflected. Further, fewer than half included studies used panel data, with the remaining studies unable to undertake more causal analyses. The results of the critical appraisal showed that lower-quality studies tended to not find a negative impact of the Recession on health, whereas higher quality studies generally did. In future, we recommend conducting cross-country comparisons, using (inter)nationally-representative panel data conducted over a minimum of a ten-year time horizon, and employing multi-faceted operationalisations of wealth and health. This could provide more common ground across studies, and a clearer indication of whether the Recession impacted health.     

Ezenwa-Ohaeto: Chants and the Minstrel

Ezenwa-Ohaeto’s life encapsulates what the critic and novelist Isidore Okpewho has described as the “dignity of intellectual labour.” This becomes clear as we take into consideration, the range of his production as a poet, scholar, and occasional journalist. Ezenwa-Ohaeto’s work grapples with a vast range of areas of specifically Nigerian literature and culture in the 20th century, but in general with the literature of the postcolonial world as they have come to express distinct, recognizable moral and aesthetic values. His untimely death in 2005 therefore, has implication for the study of this literature, particularly because it marks the closure of the questic imagination of a poet/scholar whose interventions were critical in the formation of the critical values of contemporary African writing. This paper examines Ezenwa-Ohaeto’s contributions in the light of this, and puts in some perspective, aspects of his life and work, and its implications in the formal canon that he helped to shape and stabilize.     

染色体三维结构重建方法研究

染色体三维结构重构问题是近年生物领域中基因组学的热点研究问题,是以二维交互频率数据为基础来预测其三维空间结构。最新相关实验表明染色质的三维空间结构对于基因表达、调控等方面都具有重要意义。而Hi-c数据能利用染色质交互信息形成二维接触矩阵重构出染色体三维结构。本综述以染色体三维结构重建方法为研究对象,通过对染色体三维结构重建方法进行比较分析,综述了目前基于Hi-c数据在染色体三维结构重建中的经典方法,系统介绍了染色体三维结构重建技术的发展脉络,以促进染色体三维结构重建的进一步研究。     

近十年来中国景观生态学文献分析

自80年代初期我国学者开始开展景观生态学研究以来,景观生态学的研究在我国获得了蓬勃发展,本文针对所搜集的1990－2000年我国景观生态学国内学者发表的中、英文文献619篇、著作14本,分不同专题进行分类统计,并在其基础上对我国90年代景观生态学研究进行分析和论述,为我国景观生态学者了解和把握中国景观生态学研究热点和发展趋势提供依据。     

基于CNKI和PubMed数据库的双歧杆菌研究文献分析

目的 统计分析国内外已发表的与双歧杆菌相关的期刊文献,了解其中的研究热点与发展趋势,为相关科研工作者提供参考。方法 研究资料来源于CNKI和PubMed数据库,应用文献计量学的方法对两个数据库所收录的双歧杆菌相关文献进行分析。结果 截至2018年8月15日,CNKI和PubMed分别收录了9277和5130篇相关文献。在数量上,国内外对双歧杆菌的研究都从20世纪90年代开始快速增长。从学科分布和关键词来看,中外研究共同关注了消化道疾病和儿科学,同时中外研究侧重点又有明显的差异。国内研究机构参与发表在国际杂志上的文章数量较多,但是其中作为第一发表单位的文章数量偏少。结论 双歧杆菌相关的基础与应用研究还有许多需要深入和拓展的方面,研究者应当在相关领域进行实质性突破。     

中国灵长类文献纵览

把1870-2001年来自美国"现代灵长类文献题录数据库"、"维普中文数据库"及"中国灵长类研究文献题录"的资料按4个时期(I:1870-1949;Ⅱ:1950-1965;Ⅲ:1966-1977;Ⅳ:1978-2001)分类整理.此外,使用了"科学引文数据库(扩展版)".结果如下:(1)1870-2001年共有20 52篇文献,2个文献数量高峰分别出现于1950-1965和1978-2001年;科研部门所发表的论文占54.2%,并随时间而增加;而国外部门则随之减少.(2)2 052篇文献中,超过9%的文献为SCI所收录,其中1966-1977年被SCI收录的文献百分比最高;在全部被SCI收录的文献中又以科研部门的占优势(59.1%);但国外部门则以其30.1%的文献被SCI收录而领先.(3)统计了灵长类研究9个领域文献百分比及其变化,其中1978-2001间生态学和行为、神经生物学、繁殖和饲养快速发展;化石灵长类、形态学和解剖学减少;分类及分布、细胞及分子进化显得不甚突出;在第Ⅱ时期和第Ⅳ时期疾病防治研究相当多;保护生物学得到越来越多的关注.第Ⅳ时期作者数量最多,但每个作者的文献平均数却不如第Ⅰ时期.一般地说,在SCI收录的作者中以中国作者居多,但在第I时期唯一被SCI收录的作者则是一名外国学者;在第Ⅲ时期外国作者占被收录作者数的60%.     

中药治疗胆囊息肉样病变的研究进展

随着人口年龄增长、人们生活节奏的加快及生活水平的提高,患病率的日趋增加。胆囊息肉病因复杂甚至有些息肉有癌变倾向,严重影响人民的健康和生活质量。而中药治疗PLG逐渐的得到了重视,发现中药的治疗起到了很好的疗效,尤其是不超过10mm的PLG,有待于我们进一步的研究。本文介绍了中药治疗PLG的研究进展。     

Literature mining supports a next-generation modeling approach to predict cellular byproduct secretion

The metabolic byproducts secreted by growing cells can be easily measured and provide a window into the state of a cell; they have been essential to the development of microbiology, cancer biology, and biotechnology. Progress in computational modeling of cells has made it possible to predict metabolic byproduct secretion with bottom-up reconstructions of metabolic networks. However, owing to a lack of data, it has not been possible to validate these predictions across a wide range of strains and conditions. Through literature mining, we were able to generate a database of Escherichia coli strains and their experimentally measured byproduct secretions. We simulated these strains in six historical genome-scale models of E. coli, and we report that the predictive power of the models has increased as they have expanded in size and scope. The latest genome-scale model of metabolism correctly predicts byproduct secretion for 35/89 (39%) of designs. The next-generation genome-scale model of metabolism and gene expression (ME-model) correctly predicts byproduct secretion for 40/89 (45%) of designs, and we show that ME-model predictions could be further improved through kinetic parameterization. We analyze the failure modes of these simulations and discuss opportunities to improve prediction of byproduct secretion.