Effects of regulated deficit irrigation applied at different growth stages of greenhouse grown tomato on substrate moisture,yield, fruit quality,and physiological traits

Environmental Science and Pollution Research - Given a critical water scarcity in arid and semi-arid Tunisian areas and aiming to reduce irrigation water request, it is crucial to identify and...     

生态校园建设的现状与发展趋势

在改善生态环境,维护人与自然的和谐关系,走可持续发展道路的大背景下,生态校园建设的提出具有重要的时代意义。本文总结了生态校园的概念和内涵,概括了生态校园建设的各项具体内容,并在此基础上归纳分析各学校的建设侧重点,将现有生态校园划分为景观园林设计型、环境友好技术型、生态化教育管理型三类,最后对生态校园发展趋势提出了展望。     

A Standard Lexicon for Biodiversity Conservation: Unified Classifications of Threats and Actions

Abstract: An essential foundation of any science is a standard lexicon. Any given conservation project can be described in terms of the biodiversity targets, direct threats, contributing factors at the project site, and the conservation actions that the project team is employing to change the situation. These common elements can be linked in a causal chain, which represents a theory of change about how the conservation actions are intended to bring about desired project outcomes. If project teams want to describe and share their work and learn from one another, they need a standard and precise lexicon to specifically describe each node along this chain. To date, there have been several independent efforts to develop standard classifications for the direct threats that affect biodiversity and the conservation actions required to counteract these threats. Recognizing that it is far more effective to have only one accepted global scheme, we merged these separate efforts into unified classifications of threats and actions, which we present here. Each classification is a hierarchical listing of terms and associated definitions. The classifications are comprehensive and exclusive at the upper levels of the hierarchy, expandable at the lower levels, and simple, consistent, and scalable at all levels. We tested these classifications by applying them post hoc to 1191 threatened bird species and 737 conservation projects. Almost all threats and actions could be assigned to the new classification systems, save for some cases lacking detailed information. Furthermore, the new classification systems provided an improved way of analyzing and comparing information across projects when compared with earlier systems. We believe that widespread adoption of these classifications will help practitioners more systematically identify threats and appropriate actions, managers to more efficiently set priorities and allocate resources, and most important, facilitate cross‐project learning and the development of a systematic science of conservation.     

Assessing the Potential Impact of Cane Toads on Australian Snakes

Abstract:   Cane toads ( Bufo marinus ) are large, highly toxic anurans that were introduced into Australia in 1937. Anecdotal reports suggest that the invasion of toads into an area is followed by dramatic declines in the abundance of terrestrial native frog-eating predators, but quantitative studies have been restricted to nonpredator taxa or aquatic predators and have generally reported minimal impacts. Will toads substantially affect Australian snakes? Based on geographic distributions and dietary composition, we identified 49 snake taxa as potentially at risk from toads. The impact of these feral prey also depends on the snakes' ability to survive after ingesting toad toxins. Based on decrements in locomotor (swimming) performance after ingesting toxin, we estimate the LD₅₀ of toad toxins for 10 of the at-risk snake species. Most species exhibited a similar low ability to tolerate toad toxins. Based on head widths relative to sizes of toads, we calculate that 7 of the 10 taxa could easily ingest a fatal dose of toxin in a single meal. The exceptions were two colubrid taxa (keelbacks [  Tropidonophis mairii ] and slatey-grey snakes [  Stegonotus cucullatus ]) with much higher resistance to toad toxins (up to 85-fold) and one elapid (swamp snakes [  Hemiaspis signata ]) with low resistance but a small relative head size and thus low maximum prey size. Overall, our analysis suggests that cane toads threaten populations of approximately 30% of terrestrial Australian snake species.     

基于灰色关联和主成分分析的农村建设用地集约利用评价——以江苏省为例

基于农村集体建设用地集约利用的内涵,构建了一套评价农村集体建设用地利用集约度的指标体系,并以江苏省苏南、苏中、苏北的12个行政村为例,采用灰色关联与主成分分析方法对各行政村集体建设用地利用的集约度进行了对比分析。分析结果表明:苏南地区的农村集体建设用地利用的集约度较高,而位于苏北地区的农村集体建设用地利用的集约度则相对较低,苏中地区在两者之间,整体上与江苏省区域经济的发展水平相符;从近郊与远郊的农村集体建设用地集约利用水平来看,两种评价方法测算的集约度虽有所差异,但两种方法对于近远郊的排序是基本一致的,呈现的趋势是近郊农村集体建设用地利用集约度高于远郊的。研究表明,两种方法所得的农村集体建设用地利用的集约度大致相似,在近郊远郊空间分布以及苏南、苏中、苏北的区域差异所呈现出的规律性,可为制定促进区域农村经济发展和提高农村建设用地的集约利用水平等相关的宏观政策提供参考依据。     

地铁运营事故分析及其对策研究

在对近年来国内外地铁发生的事故分析的基础上 ,笔者对影响地铁安全运营的人、车辆、轨道、供电、信号以及社会灾害等主要原因进行了探讨 ;针对这些原因提出了一些事故发生前的预防对策以及事故发生后的处理措施 ;突出强调了“以人为本”的大安全观 ,提出“人 -车 -轨道 -安全管理”的安全运营系统及应急救援体系相结合的对策。这些对策和实施的实现将会减少地铁事故的发生和降低事故造成的人员伤亡及财产损失。     

海水循环养殖系统水处理工艺综述

论述了海水循环养殖系统(RAS)需要控制的水质参数及相关单元水处理工艺.RAS需要对盐度、pH、温度、溶解氧等水质参数进行监测控制,并常采用物理、生物、化学处理的组合工艺,使固体物质、氨氮、亚硝酸盐、硝酸盐、有机物以及致病微生物等的浓度维持在安全范围内.固体物质根据粒径和可沉降性的不同,可采用沉降、过滤、泡沫分离或生物过滤法去除;氨氮、亚硝酸盐以及硝酸盐主要通过生物的硝化和反硝化作用去除;有机物主要通过生物降解去除;化学药剂消毒以及紫外辐照是RAS常用的消毒方法,消毒剂残余及消毒副产物对水质和动物健康的影响是选择合适消毒方法需要考虑的两个关键因素.最后,列举了几种海水RAS常用的组合处理工艺,并提出了针对性的改进建议.     

GJB 150.11A盐雾试验的加速等效性研究

为了研究GJB 150.11A盐雾试验与海洋气候环境盐雾腐蚀的加速关系.本文以碳钢Q235为研究对象,开展碳钢Q235在GJB 150.11A的标准试验条件下的长期盐雾腐蚀试验,并参考碳钢Q235在自然海洋环境试验场的腐蚀数据,以及GB/T 19292.1-2018的数据,给出碳钢Q235在GJB 150.11A的标准...     

基于Duane曲线的可靠性增长模型

在阐述复杂武器装备系统在研制中,通常要经过实验——分析——改进的过程,即可靠性增长过程。由于产品处于改进阶段,每个阶段的产品的寿命所对应的总体就是不同的。因此估计最后阶段的可靠度及其置信限就有了一定的困难,讨论基于Duane曲线的指数可靠性增长模型——ERG模型。完全寿命方案下,给出了利用枢轴量构建置信限的推断方法,并证明了构建的置信限具有最优性。