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41.
5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy–Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
42.
Linden F Vincent 《Natural resources forum》2003,27(2):108-116
Situations of water scarcity challenge sustainability and threaten small users' access to water. In response to this problem, there has been a search for a method of hydrological analysis that can better represent the needs of small water users. While this search is rooted in the debate favouring a more participatory and inclusive allocation of the resource, it also requires a new focus on smallholder hydrology that can confront the gaps and biases found in current hydrological practices in many countries. This article looks at past hydrological practices and also at results of recent studies, highlighting the perspective of smallholder irrigators in surface water planning in Zimbabwe, and groundwater planning in India. These case studies show that wider social forces, not always best science, drive hydrological practices. However, new frameworks focusing on the water user can emerge for more equitable and sustainable water management. 相似文献
43.
In the past 20 years a variety of indices have been suggested for measuring the severity of trauma, however none of them meets the requirement of being a simple and objective instrument that can be utilized efficiently by lay persons and providers of health services without previous experience in triaging. A new system has been proposed which meets this requirement and which has been validated with 197 injured persons at the emergency ward of the Valle University Hospital in Call, Colombia. The instrument showed a high level of concordance with the conventional triaging method and classifies victims into four categories: critical with recovery unlikely, critical but recoverable, moderately serious, and ambulatory. There is discussion on the reliability of this instrument and it is recommended that it be validated with victims from larger disasters. Regardless, it has the advantage of being specific and free of the subjectivity that characterizes other indices. 相似文献
44.
Inorganic nitrogen metabolism in blue light was studied for the green algaUlva rigida C. Agardh collected in the south of Spain (Punta Carnero, Algeciras) in the winter of 1987. NH4
+ has been reported to inhibit NO3
- uptake; however,U. rigida showed a net NO3
- uptake even when the NH4
+ concentration of the external medium was three or four times greater than the concentration of NO3
-. NO3
- uptake rates were similar in both darkness and in blue light of various photon fluence rates (PFR) ranging from 17 to 160 mol m-2 s-1. Since NO3
- uptake is an active mechanism involving the consumption of ATP, respiratory metabolism can provide enough ATP to maintain the energetic requirement of NO3
- transport even in darkness. In contrast, NO3
- reduction inU. rigida was highly dependent on the net photosynthetic rate. After 7 h in blue light, intracellular NO3
- concentrations ([NO3
-]
i
) were higher in specimens exposed to intensities below the light compensation point (LCP) than in those incubated at a PFR above the LCP. When PFR is below the light compensation point, NO3
- reduction is low, probably because all the NADH produced by the cells is oxidized in the respiratory chain in order to produce ATP to maintain a steady NO3
- transport rate. The total nitrogen (TN) and carbon (TC) contents decreased from darkness to 33 mol m-2 s-1 in blue light. In this range, catabolic processes prevailed over anabolic ones. In contrast, increases in TN and TC contents were observed above the light compensation point. The C : N ratio increased with light intensity, reaching a stable value of 17 at 78 mol m-2 s-1 in blue light. Intracellular NO3
- concentration and NO3
- reduction appear to be directly controlled by light intensity. This external control of [NO3
-]i and the small capacity ofU. rigida to retain incorporated NO3
-, NO2
- and NH4
+ ions may explain its nitrophilic character. 相似文献
45.
Cape JN Sheppard LJ Fowler D Harrison AF Parkinson JA Dao P Paterson IS 《Environmental pollution (Barking, Essex : 1987)》1992,75(2):229-236
Radioactive sulphate (35SO4) was applied to the soil below a Scots pine forest on 23 June 1989, and its movement into the canopy and into throughfall and stemflow was measured over 4 months. The specific activity, Bq (mg S)(-1), of the canopy increased monotonically; uptake by current-year (1989) expanding needles was initially twice as fast as by older needles or live twigs. By 10 October the canopy average specific activity was 62 Bq (mg S)(-1). The specific activity of net throughfall (throughfall + stemflow - rain), deduced from measurements from six throughfall collectors, six stemflow collectors and two rain collectors, fell rapidly from 12.6 Bq (mg S)(-1) in late July to <1 Bq (mg S)(-1) in mid-August. The results suggest (assuming rapid equilibration of 35S with sulphate in soil) that root-derived sulphate contributed c. 3% of sulphate in net throughfall and that dry deposition of SO2 and sulphate particles contributed c. 97% of the 0.56 g S m(-2) measured in net throughfall over the period. Simultaneous measurements of SO2 at canopy height and of NH3 above and within the canopy gave mean concentrations of 5.9 and 0.86 microg m(-3), respectively, sufficient to account for the sulphate measured in net throughfall only if codeposition of NH3 and SO2 occurred to canopy surfaces. The large values of specific activity observed in July, however, indicate that throughfall composition may be closely related to recent soil input of sulphate, and that equilibrium cannot be safely assumed. The possibility of a significant contribution of soil-derived sulphate to sulphate deposition in net throughfall cannot be ruled out on the basis of this experiment. 相似文献
46.
Many problems have been encountered in the planning and implementation of health care in refugee camps, and more specifically in the training of refugees as primary health care workers. A review of the published literature and a "survey" of the opinions and experiences of refugee, national and international health personnel regarding training has therefore been undertaken to provide an overview of what has been done and to make recommendations for future work.
The review highlights the need to reallocate resources away from high visibility emergency aid to development activities, such as training, that will create an infrastructure for primary health care and promote self-reliance. 相似文献
The review highlights the need to reallocate resources away from high visibility emergency aid to development activities, such as training, that will create an infrastructure for primary health care and promote self-reliance. 相似文献
47.
48.
49.
基于LOADEST和数字滤波的水源地基流氮素输出定量方法应用实例 总被引:2,自引:0,他引:2
地表直接径流和基流均是流域非点源氮/磷养分输出的重要水文途径.科学认识和定量模拟基流氮/磷养分输出对于准确解析水源地水体非点源污染来源至关重要.基于Load Estimator模型和数字滤波算法,建立了定量水源地基流氮素输出的方法体系.以浙江省珊溪水源地的玉泉溪流域为例,利用玉泉溪2010-01—2013-12期间逐月总氮(TN)水质监测数据和逐日流量数据,展示了该方法的计算过程.结果表明,本文建立的水源地基流氮素输出定量方法结果合理,模拟精度高,决定系数和纳什系数分别为0.83和0.80;玉泉溪流域2010—2013年TN负荷量为141.21~274.68 t·a~(-1),平均208.63 t·a~(-1),年基流TN负荷量为84.39~168.68 t·a~(-1),平均127.69 t·a~(-1);基流对玉泉溪年均TN负荷量贡献率高达60%以上,流域基流养分输出对地表水体的污染应引起足够重视. 相似文献
50.
为探究沈阳市郊区环境空气中醛酮类化合物的污染特征,于2017年8月24日—9月2日采用2,4-二硝基苯肼固相吸附/高效液相色谱方法对沈阳市郊区醛酮类化合物进行观测分析,利用美国环境保护局推荐的人体健康风险评价方法对部分有毒有害醛酮类化合物的人体健康风险进行了评价,并利用比值法对醛酮类化合物的来源进行了初步分析.结果表明:醛酮类化合物质量浓度日均值范围为23.16~38.38 μg/m3;质量浓度最高的4种醛酮类化合物依次是丙酮、甲醛、正丁醛和乙醛,其质量浓度日均值的平均值分别为8.71、5.90、5.48和2.95 μg/m3.对·OH消耗速率(LOH)贡献较大的醛酮类化合物物种是正丁醛、甲醛和乙醛,臭氧生成潜势贡献(OFP)较大的醛酮类化合物物种是甲醛、正丁醛和乙醛,在研究区影响醛酮类化合物光化学反应活性的物种主要是甲醛、乙醛和正丁醛.研究区观测期间,环境空气中甲醛和乙醛的致癌性风险值分别为1.18×10-5和5.91×10-6,对暴露人群存在潜在的致癌风险;乙醛的非致癌风险值为0.05,对暴露人群不存在非致癌风险.在研究区的一次臭氧轻度污染过程期间,环境空气中的甲醛和乙醛受天然源排放的挥发性有机物二次转化的影响减弱,甲醛、乙醛和丙酮受到炼焦工业和机动车等人为源排放的影响增强,而正丁醛主要受当地精细化工产业排放的影响.研究显示,沈阳市应加大对炼焦工业、精细化工和机动车来源排放醛酮类化合物的管制,以降低环境空气中活性醛酮类化合物及有毒有害醛酮类化合物的浓度. 相似文献