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61.
Global climate change and the implementation of energy technologies are among the most pressing issues facing society and the environment today. Related educational content spans the science disciplines. Through an analysis of introductory-level university textbooks from four major US publishers in Biology, Chemistry, and Physics, this study presents trends in terminology and content. As the defining terms, “global warming” and “climate change” are used nearly equally. However, the first location of a working definition for climate change appears earlier. Energy technologies, climate change, and related environmental issues are found, on average, on ≤4% of textbook pages, and variation is large among individual textbooks. Discipline-based trends exist, especially for the energy technologies presented. Addressed separately as a non-renewable, non-fossil fuel, nuclear energy is found on ≤1% of textbook pages and unfavorably represented. The discussion within these science disciplines has implications on introductory-level education, public perception of science, and informed citizenship.  相似文献   
62.
自20世纪中叶以来,五大湖区的水生食物网就已受到多氯联苯化合物(PCBs)的污染。对于长寿命鱼类,如湖鲟(Acipenser fulvescens),由于缺乏该物种的相对敏感性信息,一直无法确定其PCB暴露的风险。本文的研究目标就是评估湖鲟早期生命阶段对3,3''4,4''5-五氯联苯(PCB-126)或2,3,7,8-四氯二苯并-p-二恶英(TCDD)暴露的敏感性。死亡率、生长、形态和组织病理学、游泳能力和活动水平都被用作评估终点。心包和卵黄囊水肿、管状心脏、卵黄囊出血和体长较小是TCDD和PCB-126暴露中最常见的病理症状,早在受精4 d后就开始出现,其中许多的病理都以一种剂量依赖的方式发生。湖鲟体内PCB-126和TCDD的半致死剂量分别为5.4 ng/g egg(95%置信区间,3.9-7.4 ng/g egg)和0.61 ng/g egg (0.47-0.82 ng/g egg)。由此产生的PCB-126的相对强度因子(0.11)远大于世界卫生组织对鱼的估计值(毒性当量因子=0.005),这表明目前的风险评估可能低估了PCB对湖鲟的毒性。在受精60 d后,从半致死剂量中幸存的湖鲟的游泳活性和耐力均有所下降。阈值和半数效应毒性值表明,与在北美发现的另一种鲟鱼属Scaphirhynchu相比,湖鲟对PCB和TCDD更为敏感。事实上,在大湖区和其他地方的湖鲟种群都容易受到PCB/ TCDD诱导,使胚胎发育受到影响,游泳能力下降。
精选自Tillitt, D. E., Buckler, J. A., Nicks, D. K., Candrl, J. S., Claunch, R. A., Gale, R. W., Puglis, H. J., Little, E. E., Linbo, T. L. and Baker, M. (2017), Sensitivity of lake sturgeon (Acipenser fulvescens) early life stages to 2,3,7,8-tetrachlorodibenzo-P-dioxin and 3,3′,4,4′,5-pentachlorobiphenyl. Environmental Toxicology and Chemistry, 36: 988–998. doi: 10.1002/etc.3614
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3614/full
  相似文献   
63.
The amount of toxic metal accumulated by an organism is often taken as an indicator of potential toxicity. We investigated this relationship in the freshwater snail, Lymnaea stagnalis, exposed to 500 μg l−1 Al over 30 days, either alone or in the presence of phosphate (500 μg l−1 P) or a fulvic acid surrogate (FAS; 10 mg l−1 C). Behavioural activity was assessed and tissue accumulation of Al quantified. Lability of Al within the water column was a good predictor of toxicity. FAS increased both Al lability and behavioural dysfunction, whereas phosphate reduced Al lability, and completely abolished Al-induced behavioural toxicity. Tissue accumulation of Al was not linked to toxicity. Higher levels of Al were accumulated in snails exposed to Al + P, compared to those exposed to Al alone, whereas FAS reduced Al accumulation. These findings demonstrate that the degree of tissue accumulation of a metal can be independent of toxicity.  相似文献   
64.
In 2004–05, Niger suffered a food crisis during which global attention focused on high levels of acute malnutrition among children. In response, decentralised emergency nutrition programmes were introduced into much of southern Niger. Child malnutrition, however, is a chronic problem and its links with food production and household food security are complex. This qualitative, anthropological study investigates pathways by which children are rendered vulnerable in the context of a nutritional 'emergency'. It focuses on household-level decisions that determine resource allocation and childcare practices in order to explain why practices apparently detrimental to children's health persist. Risk aversion, the need to maintain self-identity and status, and constrained decision making result in a failure to invest extra necessary resources ingrowth-faltering children. Understanding and responding to the social context of child malnutrition will help humanitarian workers to integrate their efforts more effectively with longer-term development programmes aimed at improving livelihood security.  相似文献   
65.
Experimental trampling trials using a standardized methodology were undertaken in 10 replicate blocks in three vegetation types in an urban reserve in the subtropics of Australia. In each block different intensities of trampling (controls, 10, 25, 50, 100, 150, 200, 250, 300, 400 and 500 passes) were applied, and vegetation parameters were measured pre-trampling, immediately after trampling and 2 weeks later. A Fern understorey had low resistance to trampling intensity, with reductions in relative vegetation height and cover with as few as 10 passes. A Tussock grass understorey showed moderate resistance with reduction in height at 25 passes and cover at 50 passes. A Disturbed grassland dominated by lawn grasses had the highest resistance, with reductions in vegetation height at 100 passes, but cover was affected by as few as 10 passes. The resistance indices (number of passes required to reduce vegetation cover by 50%) of three vegetation types were 210, 360 and 860 passes, respectively. When these values were compared with those for 52 other vegetation types considerable variation was found within life forms, climatic zones and vegetation types indicating that the response of a specific community may not always be predictable.  相似文献   
66.
This study incorporated identity constructs into the theory of planned behaviour (TPB) to investigate intentions to engage in environmental activism. First year students and participants of a students of sustainability conference (n=169) were administered a questionnaire survey that measured standard TPB constructs as well as environmental group membership and self-identity as an environmental activist. Consistent with predictions, environmental group membership and self-identity were positive predictors of intentions. Thus, greater involvement in environmental groups and a stronger sense of the self as an environmental activist were associated with stronger intentions to engage in environmental activism. There was also evidence that self-identity was a stronger predictor of intentions for participants with low rather than high environmental group membership. In accordance with the standard TPB model, participants with more positive attitudes toward and a greater sense of normative support for environmental activism also had greater intentions to engage in the behaviour. The implications for groups seeking to harness support for activities to protect the environment are discussed.  相似文献   
67.
引言 建立海洋保护区的好处[1]是众所周知的,特别是对于珊瑚礁来说.通过理论上完全禁止在选定海域内进行任何形式的捕鱼活动,由此对捕鱼压力的降低一般可以保持以往目标鱼类[2~4]种群的数量和多样性,导致原来从渔场中消失的物种重新出现[5],而且大大提高大型掠食性鱼类的数量[6].  相似文献   
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Given that no specific provisions of the Occupational Health and Safety (OHS) Act explicitly deal with psychosocial risk factors, in Québec, occupational health and safety inspectors employed by the Commission de la santé et de la sécurité du travail (CSST) address psychosocial hazards under the Act’s general duty clause. This general duty clause and related provisions require that all employers eliminate hazards at source and protect the health of workers. More specifically, they are required to ensure that the organisation of work does not adversely affect the safety or health of the worker. Since 2004, Québec minimum standards legislation has also provided for the right of workers to an environment that is free from psychological harassment.Written from both a legal and public health perspective, this paper has two primary objectives: first, to better understand the potential and limits of the current legislative framework for the protection of the mental health of workers and second, to describe how scientific knowledge related to high risk situations for the mental health of workers might inform interventions by inspectors for the protection of workers’ mental health.  相似文献   
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