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101.
In simultaneous hermaphrodites, gender conflicts that arise from two potential mates sharing the same gender preference may
be solved through conditional reciprocity (or gamete trading). Conditional reciprocity had initially been considered widespread,
but recent studies suggest that its real occurrence may have been overestimated, possibly because most mating observations
have been performed on isolated pairs of individuals. Some resulting patterns (e.g., non-random alternation of sexual roles)
were indeed compatible with conditional reciprocity but could also have stemmed from the two partners independently executing
their own mating strategy and being experimentally enforced to do so with the same partner. Non-random alternation of gender
roles was recently documented in the simultaneously hermaphroditic freshwater snail Physa acuta. To distinguish between conditional and unconditional gender alternations, we observed copulations of individually marked
snails reared at three contrasted densities. We showed that density affected the overall frequency of copulations during the
first 2 days of the experiment with high-density boxes showing more copulations than low density boxes, but it did not affect
gender alternation patterns. A change in gender role was observed more often than expected by chance over two successive copulations
by the same individual, confirming previous studies. However, gender switches did not preferentially occur with the same partner.
We conclude that gender alternation is not due to conditional reciprocity in P. acuta. It may rather stem from each individual having a preference for gender alternation. We finally discuss the mechanisms and
the potential extent of this unconditional reciprocity. 相似文献
102.
There is a widespread consensus among sustainability experts about the need for ambitious transformative practices in order for a sustainable development to progress. Agenda 21 emphasised the need for multilevel and multi-actor governance and explicitly focused on the local level. The conceptual and analytical preference of governance beyond government has directed attention towards the interaction between state and non-state actors. The present article focuses on the role of (local) state institutions in sustainability governance. We argue that an effective implementation of sustainability in government institutions is a precondition for a successful multi-stakeholder governance of a sustainable development. The guiding question of this article is: How has sustainability been institutionalised in local governments in Germany in the last 20 years after Agenda 21 was adopted? Based on a conceptual framework, we are presenting the empirical results of a survey of 371 German cities and municipalities in this article, which primarily aims at providing empirical evidence on to what extent sustainability has been institutionalised in German local governments. The article ends with discussing the potential reasons for the institutionalisation deficit observed and gives an outlook on the potential for developing a sustainability state, that is, a state dedicated to institutionalising sustainability. 相似文献
103.
Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation Cd polluted sites. Malondialdehyde (MDA), reactive oxygen species (ROS) and antioxidases (catalase (CAT); superoxide dismutase (SOD); peroxidase (POD)) in the leaf were determined when S. alfredii was treated for 15 d with various CdCl2 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2′,7′-dichlorofluorescein (DCF), which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation. 相似文献
104.
A novel acidophile community populating waste ore deposits at an acid mine drainage site 总被引:1,自引:0,他引:1
Waste ore samples (pH 3.0) were collected at an acid mine drainage (AMD) site in Anhui, China. The present acidophillc microbial community in the waste ore was studied with 16S rRNA gene clone library and denaturing gradient gel electrophoresis (DGGE). Eighteen different clones were identified and affiliated withActinobacteria, low G + C Gram-positives, Thermomicrobia, Acidobacteria, Proteobacteria, candidate division TM7, and Planctomycetes. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity of acidophiles in the samples that were mostly novel. It is unexpected that the moderately thermophilic acidophiles were abundant in the acidic ecosystem and may play a great role in the generation of AMD. The result of DGGE was consistent with that of clone library analysis. These findings help in the better understanding of the generation mechanism of AMD and in developing a more efficient method to control AMD. 相似文献
105.
The objective of this Incubator is to stimulate research in the area of multiple jobholding (MJH), a long‐neglected topic in organizational behavior. We first discuss the prevalence of, and motivation for, MJH and then discuss possible dangers and benefits of MJH. Throughout, we discuss ideas for future research. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
106.
段乔红 《安全.健康和环境》2022,22(1):53-55
剖析了国企安全生产中发挥党组织作用的现实差距,提出了安全生产中发挥党组织作用的路径措施:深化政治建设提升引领力,抓好有效覆盖提升组织力,促进深度融合提升推动力,加强群团作用提升凝聚力,强化监督考评提升驱动力。充分发挥党组织作用,使"根"从基层扎牢、"魂"从堡垒筑强,就能本固基稳,扛起安全生产"泰山之重"的责任,引领保障企业高质量发展和建设世界一流企业行稳致远。 相似文献
107.
中华民族优秀传统文化是具有强大生命力的先进文化,是实现中国特色社会主义现代化的精神动力。加强优秀文化传统教育,对增强大学生民族自信心、自尊心和自豪感,激发爱国热情,提升思想道德水准,确立正确的人生价值目标等有着重要作用。通过整合教学内容、改进教学方法和手段、活动渗透、营造氛围、校园网络正确引导、开设选修课等措施,使学生理解和继承中华民族优秀传统文化,提高自身的人文素质。 相似文献
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