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331.
Alessandra Galiè 《Natural resources forum》2013,37(1):31-42
This paper presents the findings of a study on the governance of seed conducted in the framework of a participatory plant breeding (PPB) programme, based on a multi‐year inquiry with a panel of ten Syrian households. The study assessed the interactions between governance regimes regulating the rights to access and control genetic resources at international and national level, compared to the actual ability of the respondent women farmers to access and control the seed of varieties they co‐developed with the PPB programme. The paper argues that gender equal access to seed can “optimally” contribute to enhancing household food security in small scale farming. The paper also argues that to support a gender‐equal access to seed in the respondent households legislation needs to explicitly protect the rights of women farmers to access and share the benefits of genetic material and draw from empirical evidence of the actual access to and control of seed at ground level. 相似文献
332.
Allison E. Curry 《Traffic injury prevention》2017,18(1):35-40
Objectives: Current methods of estimating compliance with graduated driver licensing (GDL) restrictions among young drivers with intermediate driver's licenses—which include surveys, direct observations, and naturalistic studies—cannot sufficiently answer many critical foundational questions: What is the extent of noncompliance among the population of young intermediate drivers? How does compliance change over the course of licensure? How does compliance differ by driver subgroup and in certain driving environments? This article proposes an alternative and complementary approach to estimating population-level compliance with GDL nighttime and passenger restrictions via application of the quasi-induced exposure (QIE) method.Methods: The article summarizes the main limitations of previous methods employed to estimate compliance. It then introduces the proposed method of borrowing the fundamental assumption of the QIE method—that young intermediate drivers who are nonresponsible in clean (i.e., one and only one responsible driver) multivehicle crashes are reasonably representative of young intermediate drivers on the road—to estimate population-based compliance. I describe formative work that has been done to ensure this method can be validly applied among young intermediate drivers and provide a practical application of this method: an estimate of compliance with New Jersey's passenger restrictions among 8,006 nonresponsible 17- to 20-year-old intermediate drivers involved in clean 2-vehicle crashes from July 2010 through June 2012.Results: Over the study period, an estimated 8.4% (95% confidence interval, 7.8%, 9.0%) of intermediate drivers' trips were not in compliance with New Jersey's GDL passenger restriction. These findings were remarkably similar to previous estimates from more resource-intensive naturalistic studies (Goodwin et al. 2006; Klauer et al. 2011).Conclusion: Studies can practically apply proposed methods to estimate population-level compliance with GDL passenger and night restrictions; examine how compliance varies by relevant driver, vehicle, and environmental factors; and evaluate the implementation of a GDL provision or other intervention aimed at increasing compliance with these restrictions. Important considerations and potential limitations and challenges are discussed. 相似文献
333.
334.
A new FAGE setup has recently been built at the University of Lille, France. It permits the quantification of OH and HO2 in the atmosphere with a detection limit of 3×105 molecules/(cm3·min) for OH and 1×106 molecules/(cm5·min) for HO2. Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory. Two configurations have been considered: one with the photolysis cell at 90° to the FAGE nozzle, the other on line with the FAGE nozzle. The two configurations have been tested and validated by measuring the well known rate constants of OH with CH4, C3H8 and CO. The advantages and drawbacks of each configuration have been evaluated. The “on line” configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle, thus limiting the ability to carry out energy dependence studies which can, in contrast, be successfully performed in the 90° configuration. 相似文献
335.
规模化畜禽养殖小区替代分散养殖模式污染物减排核算及建议 总被引:1,自引:0,他引:1
规模化畜禽养殖小区采用生态工程处理养殖废水和粪便,是一种新出现的环保型养殖模式,与传统的分散养殖方式相比,具有集约型、减量化的特点.本文通过实地调查,监测某规模化畜禽养殖小区及其替代同等规模分散养殖户的主要污染物排放浓度和排放总量,为核算污染物初始排放量、削减量及外排量提供基础数据,以研究和核定实施集约化养殖后污染物减排成效.结果表明,规模化畜禽养殖替代散户养殖,能大幅度减少规模养殖区域养殖废水及污染物外排量,减少幅度为:废水量41.6%,COD 93.5%,NH3-N 99.9%,TP 99.4%,SS 90.5%.养殖小区通过源头减排,提高末端治理效率,并配套农牧结合的有效实施,可使替代养殖户的排污量削减全额认定,实现污染物“零排放”. 相似文献
336.
Rod N. Millward 《Chemistry and Ecology》2013,29(1-3):115-127
The demonstration of an increased tolerance to a pollutant is direct evidence that this pollutant has presented a selection pressure upon a population or community. Recently, pollution-induced community tolerance (PICT) has been applied to the benthic community in a metal-enriched estuary to establish causal linkage between observed changes in community structure and composition and the presence of copper. This paper describes the rationale and methodology behind applying PICT to the marine benthic environment, and shows it to be a sensitive ecotoxicological tool. It also presents a case study, demonstrating how a PICT investigation has aided the interpretation of changes in a benthic community, establishing a causal linkage between these changes in the community and the presence of a specific pollutant. 相似文献
337.
338.
Common murres (Uria aalge) are highly colonial; pairs often breed at the highest possible densities, in bodily contact with neighbors. At Bluff, a colony
in western Alaska, we tested for synchrony in egg laying at various spatial scales and found little evidence for higher synchrony,
either within study plots of 15–195 pairs, or within subplots containing several pairs, than among plots in a 5-year study.
Egg laying of neighbors generally was more synchronous than expected based on overall frequency distributions in laying dates,
however. Breeding success was positively correlated with the number of breeding neighbors and the number of neighbors tending
eggs or nestlings at the time of egg laying. Breeding success of pairs with neighbors was positively related to the breeding
success of neighbors. Pairs that produced eggs synchronously with at least one neighboring pair had higher success than those
that began breeding either before or after their neighbors. Most reproductive failures at Bluff are due to accidental egg
loss and predation on eggs by common ravens, Corvus corax, soon after laying. By occupying space where a raven might otherwise land and defending their own eggs, active breeding neighbors
locally reduce the probability of egg predation. Active breeding neighbors also are less likely to flush and accidentally
dislodge nearby eggs when disturbed than are nonbreeders. Murres breeding synchronously with neighbors have the highest assurance
of the presence of active breeding neighbors both at the time of egg laying and throughout their reproductive attempts. Groups
of neighboring murres can be considered small “selfish herds,” demonstrating by-product mutualism through their continued
presence and defense of their own eggs and nestlings. Despite the advantages of breeding synchronously with neighbors, early
breeding may often be favored, however.
Received: 22 January 1996/Accepted after revision: 16 June 1996 相似文献
339.
以生猪粪便制沼气为例,应用博弈论和仿真方法,探究了“熟人社会”农村和“原子化”农村中养猪户的行为演化规律和稳定策略。进而以规模养猪户微观数据为基础,应用计量经济学研究方法,对博弈和仿真结果进行了检验。研究表明:“地方性共识”引致的隐性激励是维系“熟人社会”农村生猪养殖废弃物能源化利用集体行动的重要机制。而在“原子化”农村中,由于人情机制与礼俗机制的衰弱,“地方性共识”近乎消失殆尽,养猪户倾向于成为严格的机会主义者,从而导致生猪养殖废弃物能源化利用集体行动举步维艰。据此,在强化法律法规、政策方针等正式制度建设的同时,还应推动“地方性共识”建设,以乡村文化振兴助推乡村生态振兴。 相似文献
340.
为了解渗滤液污染土壤的复电阻率特性及其与海水入侵所造成的电特性差异,指导海滨场地的污染探测,设计了黏土和砂土两种土壤,在水饱和情况下通入不同浓度的渗滤液,测量复电阻率的幅值和相位响应;在砂土中通入与渗滤液电阻率相同的模拟海水,对比海水入侵与渗滤液污染所造成的相位差异.结果表明:受渗滤液污染土壤的复电阻率变化明显,0.1 Hz下被2%渗滤液(渗滤液体积占溶液总体积比例为2%)污染的土壤中,与背景值相比,黏土的幅值和相位分别降低了78%和70%,砂土的幅值和相位分别降低了66%和33%,且渗滤液浓度越高,幅值和相位的值就越小;而对于电阻率背景值较低的土壤(如海水入侵场地或地下水-海水交错带区域),通入渗滤液后,其复电阻率参数没有明显变化.对比海水入侵与渗滤液污染,受渗滤液污染较轻的土壤的相位略高于海水入侵污染土壤,而当渗滤液浓度较高时,二者几乎没有区别.研究显示,正常条件下,复电阻率法对渗滤液污染的反映灵敏,有较好的指示意义,其参数变化主要与孔隙水中金属离子的含量和双电层极化有关;而在天然低电阻率背景条件下,渗滤液污染引起的电阻率变化很小,但相位变化较为明显,这种相位的变化有可能被识别出来. 相似文献