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181.
We report on the prenatal diagnosis of a fetus at risk of leprechaunism. We had previously determined the nature of the causative mutation in the insulin receptor gene in this family. The mutation removes a restriction site for the enzyme Mbo II. Genomic DNA was extracted from a chorionic villus sample and the 3′ half of exon 2 was amplified by the polymerase chain reaction (PCR) followed by restriction digest. Using this method, we correctly predicted an unaffected child.  相似文献   
182.
李逢帅  巨天珍  马超  咸龙 《中国环境科学》2019,39(10):4082-4092
基于OMAERUV数据日产品,对甘肃省2008~2017年吸收性气溶胶指数(UVAI)的时空分布进行了分析,并对其相关因素进行了探讨,结果表明:该省近10a UVAI空间格局为由西北向东南区域逐步递减,UVAI的高值区域一直分布在酒泉市及邻近区域,为吸收性气溶胶污染源中心;甘肃省UVAI的稳定性呈现从东北向西南区域逐渐降低的规律;UVAI月均值呈现出明显的规律性,每年的月变化均呈现"V"型;四季UVAI水平为:冬季 > 春季 > 秋季 > 夏季,四季变化规律基本同步,十年来四季的UVAI呈逐渐上升趋势,且四季中主导的吸收性气溶胶来源不同.基于PM2.5的UVAI指示的空气质量等级分析,甘肃省空气质量以良为主;从气象因素与UVAI相关性分析来看,降水量、气温均与UVAI之间呈现显著正相关,风向也对其空间分布有重要影响;植被覆盖度与UVAI呈现正相关的区域主要分布在甘肃省西北部、武威市中部区域,呈现负相关的甘肃南部天水、陇南等区域为较高的植被覆盖区域.从人类活动因子与UVAI相关性来看,地区生产总值、各产业产值与UVAI有着明显的正相关性,尤其以第二产业与UVAI相关性最高;UVAI与汽车保有量、能源消耗总量及人口密度均存在较强的正相关,说明汽车尾气和工业排放及建筑粉尘也是吸收性气溶胶的重要来源.针对甘肃省UVAI时空分布特点、自然及人类活动因素分析情况,提出了减少人类活动强度等建议.  相似文献   
183.
Epignathi are unusual congenital tumours presenting as oropharyngeal masses, often resulting in rapid asphyxia following birth. Occasionally, intracranial extension of the tumour is present, and two such cases are described. The presence of this complication, diagnosable by ultrasound examination, indicates that aggressive surgical treatment is inappropriate.  相似文献   
184.
四川某公路崩塌堆积体稳定性评价   总被引:3,自引:0,他引:3  
巨能攀  涂国祥  邓辉 《地球与环境》2005,33(Z1):412-416
堆积体位于四川某公路K43+040-K43+210段岷江左岸,其物质组成主要是后缘基岩崩塌形成的粒径较大的块体,架空现象明显。特殊的物质组成及其结构特征使得采用传统稳定性评价方法评价其稳定性时面临诸多问题。本文在大量野外现场调查的基础上,分析研究了堆积体的形成机制、坡体结构特征,在此基础上,运用离散元方法分析了堆积体开挖后的变形破坏特征及其运动过程,同时采用定性和定量相结合的方法对堆积体的稳定性进行了综合评价。  相似文献   
185.
岩体质量对地下洞室围岩稳定性的影响   总被引:3,自引:0,他引:3  
卢书强  巨能攀  许模  邓辉 《地球与环境》2005,33(Z1):319-324
在现场调查的基础上,通过对西南某电站地下厂房洞室群围岩岩体质量的分析评价,采用三维有限元数值分析方法,对比分析不同岩体质量条件下,洞室开挖后围岩的二次应力场、变形场和塑性破坏区的差异。较全面地讨论了岩体质量对地下洞室围岩稳定性的影响。  相似文献   
186.
Plant uptake of non-ionic organic chemicals from soils   总被引:15,自引:0,他引:15  
Methodologies utilizing simple properties of chemicals - half-life (T1/2), log octanol-water partition coefficient (log Kow) and Henery's Law constant (Hc) - are developed to screen organic chemicals for potential plant uptake.  相似文献   
187.
In 1997, the U.S. Environmental Protection Agency revised the National Ambient Air Quality Standard governing ozone (O3), adding an 8-hr standard of 0.08 ppm and phasing out the 1-hr requirement of 0.12 ppm. The 8-hr standard is intended to provide greater protection for human health. This research examines spatial and temporal patterns of exceedances of the standards using monitoring data and modeled estimates. The Penn State/National Center for Atmospheric Research Mesoscale Model and Models-3 framework were used to estimate hourly O3 concentrations for 4-km resolution in the Maryland/Virginia/Delaware/Washington, DC, and northern Georgia domains. Results reveal that the spatial and temporal nature of compliance is considerably different under the 8-hr standard. In the modeling simulations, the 8-hr standard was exceeded 2-5.2 times more often and in a 1.8-16.2 times larger area than the 1-hr standard. The 8-hr standard was exceeded in areas that generally comply with the 1-hr standard and are not well covered by the monitoring network. These results imply that a larger population resides in areas with unhealthy O3 levels than noncompliance with the original 1-hr standard suggests. For the MD/VA/DE/DC domains, 80 and 98% of the total population live in areas with 8-hr National Ambient Air Quality Standards (NAAQS) exceedances for the 1990 and 1995 episodes, respectively.  相似文献   
188.
以MODIS遥感影像数据为数据源,应用遥感和GIS技术对泾河流域植被覆盖格局进行分析。结果表明:(1)泾河流域植被覆盖类型以退化草地和草地为主,二者占流域总面积的53.30%;地面覆盖程度较高的森林、疏林仅占流域总面积的9.83%,流域植被覆盖程度较低。(2)受自然环境条件和人类活动的影响,退化草地、稀疏灌丛、郁闭灌丛和疏林破碎化程度较为严重,对地面覆盖程度最低的退化草地除集中分布于流域北部外,主要零散分布于流域中、南部,其斑块形状复杂多样,数量最多,应成为流域植被恢复的重点。(3)各植被覆盖类型的斑快数量组成以小斑块所占比例最大,最小斑块比率均在50.0%以上;森林的斑块面积多样性最大,草地的斑块面积多样性最小。  相似文献   
189.
Recent studies have pointed to evidence that fine particles in the air could be significant contributors to respiratory and cardiovascular diseases and mortality. Epidemiologists looking at the health effects of particulate pollution need more information from various receptor locations to improve the understanding of this problem. Detailed information on temporal, spatial and size distributions of particulate pollution in urban areas is also important for air quality modellers as well as being an aid to decision and policy makers of local authorities. This paper presents a detailed analysis of temporal and seasonal variation of PM(10) and PM(2.5) levels at one urban roadside, one urban background and one rural monitoring location. Levels of PM(10), PM(2.5) and coarse fraction of particulates are compared. In addition, particulate levels are compared with NO(2) and CO concentrations. The study concludes that PM(10) and PM(2.5) are closely related at urban locations. Diurnal variation in PM(2.5)/PM(10) ratio shows the influence of vehicular emission and movement on size distribution. This ratio is higher in winter than in summer, indicating a build-up or longer residence time of finer particulates or washout due to wet weather in winter. In the second part of this study, a disease burden analysis is carried out based on the dose-response relationships recommended by the UK Committee on the Medical Effects of Air Pollution. The disease burden analysis indicates that if Marylebone Road (MR) levels of PM(10) were prevalent all over London, it will result in around 2.5% increase in death rates due to all causes. Whereas, if Bloomsbury (BB) levels were prevalent in London, which is more likely to occur as this is more representative of the urban background environment to which people in London are likely to be exposed, the corresponding increase would be around 1.7%. Considering this, in London, at Bloomsbury levels, 973 deaths and 1515 respiratory hospital admissions (RHA) are attributable to PM(10) while 2140 RHA are attributable to NO(2). After deducting the disease burden due to background levels at Rochester (RC), PM(10) emission caused by anthropogenic activities in London equates to 273 additional deaths and 410 additional RHA, while NO(2) account for additional 1205 incidences of RHA.  相似文献   
190.
Emissions of ammonia have received increasing attention recently, following concern about the environmental consequences, especially in The Netherlands where levels are high due to intensive livestock farming. Direct local effects and more widespread consequences for a range of ecosystems have been attributed to ammonia emissions. As the most prevalent alkaline gas in the atmosphere, ammonia interacts with acidic species, changing their characteristics, chemical and physical behaviour, and enhancing their potential for acidification of soils. Ammonia also forms an important component of the nitrogen cycle and of nitrogen deposition. In the UK, as in many other European countries, there has been a considerable increase in the emission of ammonia within the last 30 years, estimated at about 50%. This results mainly from increases in agricultural production based on the steadily rising number of livestock and increasing fertilizer consumption. This paper discusses the various sources to emissions of ammonia from agricultural sources in the United Kingdom, and some of the uncertainties involved in constructing a national emissions inventory.  相似文献   
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