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Carvalho FP 《Journal of environmental radioactivity》2011,102(5):462-472
The determination of 210Po and 210Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10−1 Bq kg−1 (wet wt.) in jellyfish, to very high values of about of 3 × 104 Bq kg−1 (wet wt.) in the gut walls of sardines, with a common pattern of 210Po > 210Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that 210Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As 210Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, 210Po transfer factors are similar to ecotrophic coefficients. 210Pb is transferred less efficiently in marine food chains and this contributes to increased 210Po:210Pb activity ratios in some trophic levels. 相似文献
954.
实验教学是高职教育中不可缺少的环节,多媒体课件的制作与演示性实验教学作为重要的教学方法可以应用于高职食品工艺学的辅助教学.本文介绍了食品工艺实验室设计及教学方法的要求和特点,为使食品工艺实验室实现可持续发展,该实验教学必须与其他学科结合,实验项目必须反映加工新技术,培养学生自发动手动脑能力. 相似文献
955.
Selective Patronage and Social Justice: Local Food Consumer Campaigns in Historical Context 总被引:1,自引:1,他引:0
C. Clare Hinrichs Patricia Allen 《Journal of Agricultural and Environmental Ethics》2008,21(4):329-352
In the early 2000s, the development of local food systems in advanced industrial countries has expanded beyond creation and
support of farmers’ markets and community supported agriculture farms and projects to include targeted Buy Local Food campaigns.
Non-governmental groups in many U.S. places and regions have launched such campaigns with the intent of motivating and directing
consumers toward more local food purchasing in general. This article examines the current manifestations and possibilities
for social justice concerns in Buy Local Food campaigns, by considering them within the more general category of “selective
patronage“ campaigns. Historical campaign examples, such as Buy Union, Buy American, and Buy Black campaigns, offer instructive
comparisons to contemporary consumer campaigns promoting local food. Through examining the construction of threats, intended
beneficiaries, products to be avoided, and those to be preferentially selected, the paper demonstrates how selective patronage
campaigns have emphasized social justice needs and concerns for designated groups in ways that have been potentially exclusionary
of other disadvantaged groups and thus undermining of social justice more broadly. As a contemporary instance of “selective
patronage,“ Buy Local Food campaigns exhibit similar contradictory impulses, which are intensified by the conceptual and practical
pitfalls in designating “local.“ The article concludes by considering how the challenges and prospects for commitments to
social justice in local food consumer campaigns reinforce the importance of emerging initiatives centered on domestic fair
trade. 相似文献
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目前关于药物在水生生物中富集的报道越来越多,但人们对它们在水生食物网中的营养转移却知之甚少。选择了2种在水环境中经常被监测到的选择性5-羟色胺再摄取抑制剂(SSRIs),本文在实验室可控条件下,通过构建水生链的SSRIs暴露试验,研究了舍曲林和氟西汀的生物积累和营养动力学。在2个3层食物链中(Acer platanoides,是 Asellus aquaticus的食物,而相应地 Asellus aquaticus是Notonecta glauca 或 Pungitius pungitius的食物),随着营养级的递增,这2种可离子化的、弱碱药物均显示出较低的生物积累因子(BAFs)(这表明没有生物放大)。A. platanoides、A. aquaticus、N. glauca和P. pungitius体内的舍曲林的平均BAFs分别为2200 L/kg、360 L/kg、26 L/kg和49 L/kg,氟西汀的平均BAFs分别为1300 L/kg、110 L/kg、11 L/kg和41 L/kg。生物积累因子(BAFs)的测量值等于或低于生物富集因子(BCFs)的测量值,这进一步证明了饮食的微弱影响。生物脂含量与BAFs没有正相关性,这表明其他的过程在驱动SSRI生物累积的种间差异。这里将经验参数值带入一个生物累积模型中计算,发现模拟与经验BAFs(预测r2=-0.63)之间相关性较差。综上所述,这些可离子化的药物明显缺乏生物放大作用,环境问题不应只关注较高的营养水平,而应关注在任何营养水平上有高BCFs的物种。
精选自Bostr?m, M. L., Ugge, G., J?nsson, J. ?. and Berglund, O. (2017), Bioaccumulation and trophodynamics of the antidepressants sertraline and fluoxetine in laboratory-constructed, 3-level aquatic food chains. Environmental Toxicology and Chemistry, 36: 1029–1037. doi: 10.1002/etc.3637
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3637/full 相似文献
958.
Evonne Donaher 《Local Environment》2017,22(6):746-763
This research examines price in local food systems to identify whether the perception that local is more expensive is justified. This study seeks to contribute to the field by addressing the dearth of quantitative price and availability research and building upon existing empirical research by considering a broader range of distribution channels and organic produce. Without a stronger understanding of pricing structures and distribution models, local food initiatives are based on assumptions rather than evidence. Using a case-study approach of the Region of Waterloo (Ontario, Canada), price and product data were collected at 11 outlets over a 6-month period. The study involved regression analysis of six locally produced fruits and vegetables based on local, Ontario, and organic attributes associated with the products and comparison with consumer willingness-to-pay research. Results show that local produce in the case study is not consistently more expensive than the non-local option. Both price discounts and premiums are found, depending on the product. These findings challenge the “local is more expensive” assumption and support suggestions that local food systems can be spaces for social inclusion. The organic attribute is associated with a price premium in all cases and may create confusion among consumers given frequent overlap between the local and organic attributes. Proponents of local food can use the results of this study to inform programme and policy development. Most notably, the study suggests that education around the distinction between local and organic as well as challenges to the price perception could be of benefit. 相似文献
959.
Victoria Morckel 《Local Environment》2017,22(10):1268-1289
This study examines the effects of relocating the Flint Farmers’ Market, a large and successful market in the medium-sized legacy city of Flint, Michigan. Over the course of a year, market patrons and vendors were surveyed to explore questions about the scale of the market, patron demographics, reasons for visiting the market, seasonal variations in outcomes, and healthy food access. The results indicate that the relocated, downtown market is successful in large part because it satisfies multiple needs – it provides access to fresh, local produce; it provides lunch options for downtown workers and students; and it serves as a community gathering space. The study further demonstrates that farmers’ markets in legacy cities can serve a large region, attract diverse customers, and remain sustainable year-round, even in northern climates. These findings should be of interest to planners, policy-makers, and market managers who are considering opening or relocating a farmers’ market as a means of supporting community health, well-being, and economic development. 相似文献
960.
Renganathan Kathiravan Raguru Pandu Kumudini Devi 《International Journal of Green Energy》2017,14(11):934-950
A new optimal power flow model for wind, solar, and solar-thermal bundled power scheduling and dispatch is proposed, incorporating the deviation incentive/penalty charges for renewable energy introduced in India. The multiobjective function is solved using the flower pollination algorithm; the scheme is successfully tested on the IEEE 30-bus and Indian utility 30-bus systems. The forecasting error constraints introduced in renewable energy scheduling and dispatch are demonstrated to be beneficial in several aspects. Solar-thermal bundling is shown to create win-win situations for thermal and solar generators. The effectiveness of the flower pollination algorithm in solving optimal power flow models is proved. 相似文献