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121.
固定化细胞技术及应用于废水处理的最新进展 总被引:2,自引:0,他引:2
本文简要介绍了用于废水处理的固定化细胞技术及应用此技术进行废水处理的七个领域的最新成就。 相似文献
122.
The European Commission Biocidal Products Directive 98/8/EC lays down rules and procedures concerning the placing of biocidal products on the EU market. Based on the Directive, a First Review Regulation was adopted for the review of existing biocidal active substances. These substances had to be either identified or notified (two different processes) to the European Chemicals Bureau (ECB) by 28 March 2002. More than 1000 companies took part in the review programme. In total 953 different existing active substances were identified and 372 different substances were notified. This article presents an analysis of the notified substances regarding the number of notifications per substance, notifiers per substance and per Member State and number of notified substances per product type. The results are compared with data from former statistics. 相似文献
123.
Time constraints and multiple choice criteria in the sampling behaviour and mate choice of the fiddler crab,Uca annulipes 总被引:9,自引:0,他引:9
Active female sampling occurs in the fiddler crab Uca annulipes. Females sample the burrows of several males before remaining to mate in the burrow of the chosen partner. Females time larval
release to coincide with the following nocturnal spring tide and must therefore leave sufficient time for embryonic development
after mating. Here we show how this temporal constraint on search time affects female choosiness. We found that, at the start
of the sampling period (when time constraints are minimal), females selectively sample the larger males in the population.
Towards the end of the sampling period (when the temporal constraints increase the costs of sampling), females are less selective.
Furthermore, we suggest that the number of males sampled (and other indices of ‘‘sampling effort’’) may not be reliable indicators
of female choosiness and may not reflect the strength of female mating preferences under certain conditions. Burrow quality
also emerged as an important criterion in final mate choice. Burrow structure potentially influences reproductive success,
and mate acceptance based on burrow structure appears to involve a relatively invariant threshold criterion. Since there is
no relationship between male size and burrow quality, females are using at least two independent criteria when choosing potential
mates. We envisage mate choice as a two-stage process. First, females select which males to sample based on male size. They
then decide whether or not to mate with a male based on burrow features. This sampling process explains how two unrelated
variables can both predict male mating success.
Received: 23 March 1995/Accepted after revision: 14 January 1996 相似文献
124.
我国自然保护区有效管理评价指标研究 总被引:1,自引:0,他引:1
本文根据我国自然保护区建设速度较快但管理水平较低的现状,在多年调查研究的基础上,提出制定自然保护区有效管理评价标准的必要性,并详细阐述了在保护区管理条件、管理措施、科研基础和管理成效等四个方面的评价内容,提出13项评价指标,进而作了详细的评分等级划分,提出一套评价全国自然保护区管理质量的指标体系,为全国自然保护区管理的监督检查提供了一套简便适用、易于操作的评判标准。 相似文献
125.
GREG J. McINERNY DAVID L. ROBERTS†‡ ANTHONY J. DAVY PHILLIP J. CRIBB† 《Conservation biology》2006,20(2):562-567
Abstract: We are now entering a time of immense environmental upheaval in which, increasingly, experts are required to provide conservation assessments. Quantitative assessment of trends in species' range and abundance is costly, requiring extensive field studies over a long period of time. Unfortunately, many species are only known through a few "chance" sightings or a handful of specimens, and therefore extinction may be even harder to ascertain. Several methods have been proposed for estimating the probability of extinction. However, comparison within and between species is difficult because of variations in sighting rates. We applied a probabilistic method that incorporates sighting rate to the sighting record of Vietnamese slipper orchids ( Paphiopedilum ). The method generates a probability that another sighting will occur given the previous sighting rate and the time since last observation. This allows greater comparability between species discovered at different times. Its predictions were more highly correlated with the World Conservation Union criteria than previous methods. Trends in data collection and the political climate of a country, which affects access to material, are important potential sources of variation that affect sighting rates. A lack of understanding of the process by which data are generated makes inferring extinction from sighting records difficult because extinction status depends on how the sighting rate varies. However, such methods allow rapid conservation prioritization of taxa that are poorly known and would otherwise go unassessed. 相似文献
126.
National Threatened Species Listing Based on IUCN Criteria and Regional Guidelines: Current Status and Future Perspectives 总被引:3,自引:0,他引:3
127.
太湖湖内综合治理技术探讨 总被引:11,自引:0,他引:11
简要介绍和探讨了在太湖已有一定研究基础并可供开展的局部重污染湖区底泥疏浚、湖区北部藻类收集、生态渔业建设、取水口水源净化保护工程和水生植被保护和重建等5种湖内综合治理技术、比较了它们的适用范围和预期效果。 相似文献
128.
Globally, gastric cancer (GC) ranks fifth in prevalence and third in fatalities, and shows a distinct geographical distribution in morbidity and mortality. Such a spatial pattern indicates that environmental factors could be an important contributor to GC. We reviewed a total of 135 relevant peer-reviewed articles and other literature published 1936–2019 to investigate the scientific evidence concerning the effects of environmental factors on GC worldwide. Environmental factors affect GC from the aspects of water, soil, air, radiation, and geology. Risk factors identified include water type, water pollution, water hardness, soil type, soil pollution, soil element content, climate change, air pollution, radiation, altitude, latitude, topography, and lithology; and most of them have an adverse impact on GC. Furthermore, we found that their effects followed five common rules: (1) the leading environmental factors that affect GC incidence and mortality vary by region, (2) the same environmental factors may have different effects on GC in different regions, (3) some different environmental factors have similar effects on GC in essence, (4) different environmental factors often interact to have combined or synergistic effects on GC, and (5) environmental factors can affect human factors to have an impact on GC. Environmental factors have a great impact on GC. Human beings may prevent GC by controlling carcinogenic factors, screening high-risk populations and providing symptomatic and rehabilitative treatments. Furthermore, adaptation measures are recommended to reduce GC risk on private and public levels. Future studies should transcend existing empirical studies to develop causal relationship models and focus on vulnerable population analysis. 相似文献
129.
Shouliang Huo Chunzi M Beidou Xi Yali Zhang Fengchang Wu Hongliang Liu 《环境科学学报(英文版)》2018,30(5):54-66
Nutrient criteria provide a scientific foundation for the comprehensive evaluation, prevention,control and management of water eutrophication. In this review, the literature was examined to systematically evaluate the benefits, drawbacks, and applications of statistical analysis,paleolimnological reconstruction, stressor-response model, and model inference approaches for nutrient criteria determination. The developments and challenges in the determination of nutrient criteria in lakes and reservoirs are presented. Reference lakes can reflect the original states of lakes, but reference sites are often unavailable. Using the paleolimnological reconstruction method, it is often difficult to reconstruct the historical nutrient conditions of shallow lakes in which the sediments are easily disturbed. The model inference approach requires sufficient data to identify the appropriate equations and characterize a waterbody or group of waterbodies, thereby increasing the difficulty of establishing nutrient criteria. The stressor-response model is a potential development direction for nutrient criteria determination, and the mechanisms of stressor-response models should be studied further. Based on studies of the relationships among water ecological criteria, eutrophication, nutrient criteria and plankton, methods for determining nutrient criteria should be closely integrated with water management requirements. 相似文献
130.
IntroductionThe evaluation of head protection systems needs proper knowledge of the head impact conditions in terms of impact speed and angle, as well as a realistic estimation of brain tolerance limits. In current bicycle helmet test procedures, both of these aspects should be improved. Method: The present paper suggests a bicycle helmet evaluation methodology based on realistic impact conditions and consideration of tissue level brain injury risk, in addition to well known headform kinematic parameters. The method is then applied to a set of 32 existing helmets, leading to a total of 576 experimental impact tests followed by 576 numerical simulations of the brain response. Results: It is shown that the most critical impacts are the linear-lateral ones as well as the oblique impact leading to rotation around the vertical axis (ZRot), leading both to around 50% risks of moderate neurological injuries. Based on this test method, the study enables us to compare the protection capability of a given helmet and eventually to compare helmets via a dedicated rating system. 相似文献