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71.
Environmental Science and Pollution Research - The sensitivity of anuran to the effects of habitat destruction and contamination has led to a preoccupying global decline in their populations....  相似文献   
72.
Performing hot work on a process vessel that previously contained a flammable hydrocarbon liquid poses a significant explosion and fire hazard. To reduce the combustion hazard potential, the facility operator may choose to purge and blanket the vessel with an inert gas such as nitrogen or carbon dioxide. Numerous accidents have occurred during hot work due to inadequate inerting operations. Oftentimes the source of the problem was inadequate gas composition control caused by gas buoyancy.A useful paradigm for analyzing the inerting process is the well-stirred control volume with a spatially uniform chemical composition (i.e., perfect mixing). Certain features of the vessel construction, in concert with the physical properties of the inert gas, can interfere with the complete mixing of the inert gas with the vessel atmosphere. This paper discusses how to evaluate the potential for buoyant flows to disrupt and interfere with the design goal of perfect mixing. Three case studies of accident investigations are used to illustrate the potentially detrimental effects of buoyancy on inerting operations. Finally, recommendations are presented on how to use buoyancy to improve the effectiveness of inerting operations.  相似文献   
73.
By interpreting disasters as opportunities to initiate the fulfilment of development needs, realise the vulnerability of the affected community and environment, and extend the legacy of relief funds and effort, this paper builds upon the concept linking relief, rehabilitation and development (LRRD) in the sanitation sector. It aims to use a composite of case studies to devise a framework for a semi‐hypothetical scenario to identify critical components and generic processes for a LRRD action plan. The scenario is based on a latrine wetland sanitation system in a Muslim community. Several sub‐frameworks are developed: (i) latrine design; (ii) assessment of human waste treatment; (iii) connective sanitation promotion strategy; and (iv) ecological systems and environmental services for sanitation and development. This scenario illustrates the complex issues involved in LRRD in sanitation work and provides technical notes and references for a legacy plan for disaster relief and development.  相似文献   
74.
了解与水产饲料有关的环境负荷是评价和改进水产养殖环境性能的一项重要内容.本研究的目的是利用寿命周期评估(LCA)评价与法国用于硬头鳟生产的饲料有关的环境影响.所评价的各个阶段为:原材料的提取,所使用的原始配料的生产与改造,饲料的生产,饲料在养殖场的使用,各个阶段的运输以及能源的生产和使用.评价结果显示,渔业资源的利用(例如生物资源利用)以及养殖场中营养物的排放(例如富营养化潜能)对鲑科鱼饲料的潜在环境影响所起作用最大.改进饲料的组成以及管理做法看来是改善水产饲料环境概貌的最佳途径.  相似文献   
75.
76.
The control and prevention of nutrient pollution from fish farming plays an essential role in the French regulatory framework. Assessing nutrient emissions from fish farms is important in terms of farm authorization, taxation, and monitoring. Currently employed strategies involve both water sampling and empirical modeling. This article reports the work and outcomes of an expert panel that evaluated existing methodologies and their possible alternatives. The development and evaluation of a nutrient-balance approach was assessed as a potential alternative to currently used methodologies. A previously described nutrient-balance model was suggested and parameterized using expert choice, and its validity and applicability were assessed. The results stress that the nutrient-balance model provides more robust and relatively conservative waste estimates compared to the currently used methodologies. Sensitivity of the approach to the uneven data quality available at farm level, difficulties of on-farm measurements, as well as model requirements and limitations are discussed.  相似文献   
77.
Transvaginal chorionic villus sampling (CVS) using concurrent transabdominal ultrasound guidance was performed in six women who desired CVS but could not be offered transcervical or transabdominal approaches because of uterine position and placental location. Satisfactory amounts of chorionic villi were obtained in all six cases with no maternal discomfort, an occurrence that contrasts with our experience in transvaginal CVS using endovaginal ultrasound guidance. We believe that transvaginal CVS using concurrent transabdominal ultrasound guidance warrants consideration as an alternative technique for first-trimester CVS in selected patients.  相似文献   
78.
In our previous work we have isolated fetal cells from maternal blood and used fluorescent in situ hybridization (FISH) for chromosome-specific probes to detect aneuploidy. Current efforts in the Baylor College of Medicine programme are focusing on obtaining consistency in flow-sorting methodology and on determining sensitivity and specificity. To this end, systematic evaluation of five glycophorin A (gly A) antibodies all produced agglutination, leading us to abandon the use of gly A antibodies for positive selection of fetal cells. Conversely, we have found LDS-751 to be useful for nuclear selection. CD45 negative selection can best be accomplished by the use of flasks coated with goat antibodies against mouse antibodies. Positive selection by flow sorting for either CD71+ cells or gamma-globin-positive cells seems to be successful. Using these two approaches, we have recently detected male (fetal) cells in pregnancies in which the fetus was 46, XY in 10 of 18 and in 12 of 14 cases, respectively.  相似文献   
79.
Recent reports have indicated an increased risk for fetal chromosome abnormalities, especially autosomal trisomy, in fetuses with isolated cystic hygroma, or prominent nuchal membranes, detected by ultrasonography during the first trimester. However, these reports present contradictory information regarding the prognostic significance of septations within the cystic hygroma. We evaluated, in blind fashion, 55 consecutive cases of isolatd fetal cystic hygroma detected at or before 13·9 weeks' gestation to determine the association between septations and fetal chromosome complement. Septations were associated (P<0·05) with an increased risk for fetal chromosome abnormalities. However, the incidence of chromosome abnormalities was also increased (12·5 per cent) among cases not characterized by septations. Thus, we believe it prudent to offer invasive prenatal testing to all women found to be carrying fetuses with cystic hygroma, irrespective of the presence or absence of septations.  相似文献   
80.
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