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The acute toxicity test is described in this experiment where the Collembola species Proisotoma minuta was exposed to herbicides in an artificial sea salt solution for seven days. The salt solution did not prohibit the insects' reproduction system. The seven day LD50 values for trifluralin, pendimethalin, metolachlor, prometryn, paraquat, atrazine, fluometuron, and diuron were 3.48, 10.4, 12.4, 13.0, 23.1, 33.4, 250, and 711 mg L(-1), respectively. A good correlation between toxicity of the compounds and their lipophilicity and vapor pressure was recorded in this study.  相似文献   
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The Role of the Concept of the Natural (Naturalness) in Organic Farming   总被引:1,自引:3,他引:1  
Producers, traders, and consumers oforganic food regularly use the concept of thenatural (naturalness) to characterize organicagriculture and or organic food, in contrast tothe unnaturalness of conventional agriculture.Critics sometimes argue that such use lacks anyrational (scientific) basis and only refers tosentiment. In our project, we made an attemptto clarify the content and the use of theconcepts of nature and naturalness in organicagriculture, to relate this conception todiscussions within bioethical literature, andto draw the implications for agriculturalpractice and policy.Qualitative interviews were executed with arange of people in the field of organicagriculture and with consumers of organicproducts, on the basis of a list of statementsabout the meaning of the concept of naturalnessformulated by the authors. Based on the resultsof the interviews, we distinguished 3 aspectsof the concept of naturalness: natural as theorganic (life processes), natural as theecological, and natural as referring to thecharacteristic nature of an entity. We relatedthese conceptual aspects to three mainapproaches within the field of organicagriculture: the no chemicals approach, theagro-ecological approach, and the integrityapproach. It became clear that these approachescan also be recognized in the change ofattitude of farmers as they convert fromconventional to organic agriculture, and in theattitudes of consumers of organic foodproducts.We conclude that the idea of ``naturalness' canbe used to characterize organic agriculture andto distinguish it from conventionalagriculture, but only if naturalness not onlyrefers to not using chemicals but also toecological principles and respect for theintegrity of life. Thus perceived, theprinciple of naturalness can also serve as aguide to future developments in the field oforganic agriculture. As part of the holocentricethics of organic farming the value ofnaturalness has three dimensions: a cognitiveone, an emotive one, and a normative one.  相似文献   
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Several studies have indicated the importance of understanding farmers’ perceptions of risks associated with climate change, the adaptation strategies they employ and factors that affect adaptive capacity. This study aimed to understand smallholder farmers’ perceptions of climate change, adaptation strategies and adaptive capacity in the semiarid Matungulu Sub-County, Eastern Kenya. A participatory approach, using three climate roundtables, was conducted to enhance community participation and understanding of climate change issues. The study showed that farmers’ perceptions concerning climate change are influenced by past experiences of weather extremes that have affected production levels and farm incomes. The farmers have made strategic responses to manage risks posed by climate change. However, they face several challenges in adaptation such as inadequate technical knowledge, low financial resources and inadequate land size. Further, the study showed that climate roundtables is a successful participatory approach that can give effective insights for smallholder farmers to understand agricultural vulnerability, climate change and their adaptation strategies.  相似文献   
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Environmental Science and Pollution Research - Accumulation of copper (Cu) in soils due to the application of fungicides may be toxic for organisms and hence affect winegrowing sustainability. Soil...  相似文献   
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This article examines results from in-depth interviews conducted with parents of children with asthma living in an urban environment. We examine themes from the in-depth interviews related to participants' perceptions of the influence of their physical environment on their mental and physical health, and the actions that they take in an effort to protect their health within this context. The findings from this study suggest several implications for understanding the interface between the physical environment of urban communities and residents' health, as well as for the policy and practice of risk assessment strategies.  相似文献   
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To propose specific adaptation strategies in the agricultural sector based on vulnerability to climate variability and climate change at the local level, we built a vulnerability index using an indicator tool at a fine spatial scale. This index was applied as a case study in the municipality of Guasave, Sinaloa, Mexico, at the basic census area (BCA) level. We used a total of 37 variables organized into three groups with equal weighting: exposure (13), sensitivity (13), and adaptive capacity (11). From the 20 rural BCAs located in the study area, eight were categorized as having very low vulnerability; five had low vulnerability; two had medium vulnerability because of the lack of basic services (sewers, water, and electricity) and a high rural population density; three had high vulnerability due to a high frequency of days with temperatures below 5 °C and the lack of basic services; and two had very high vulnerability, characterized by a high percentage of production units (PUs) with losses due to climate factors, a high rural population density, and a high frequency of days with temperatures below 5 °C. Approximately 50 % of the municipal rural population lives in BCAs vulnerable to climate change. This methodology allowed us to identify the most susceptible agricultural areas at the local level and the variables that require more attention so that we can propose adaptation strategies and minimize vulnerability due to climate change.  相似文献   
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Congenital left ventricular diverticulum is a rare malformation. We report a case of a ruptured congenital left ventricular diverticulum in a 24-week-old fetus. The fetus was referred for a large and circumferential pericardial effusion confirmed by cross-sectional echocardiography in our tertiary fetal cardiology unit. Pericardiocentesis removed 25 mL of old hematic fluid. The fetus died 5 days later. The pathological examination showed a ruptured submitral fibrous diverticulum of the posterior wall of the left ventricle. There is no previous report in the literature of prenatal rupture of a cardiac diverticulum. The submitral location and the fibrous wall of the diverticulum is uncommon. As regards this case, we reviewed the diagnostic criteria and the outcome of 11 cases of prenatal cardiac diverticulum reported in the literature. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
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