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991.
Restrictions in the USA on registered sex offenders (RSOs) are examined from the spatial aspects. The long history of various restrictions imposed by government, particularly local ones, is covered in the introduction. Spatial aspects, such as delineation of zones from which certain activities or certain people are excluded is the focus. Then the nature of restrictions on RSOs is considered at the state, county and municipal level. Typical of restrictions are that RSOs are prohibited from moving into residence within a prescribed distance of certain features in a community. The distances are typically 1,000 feet but are quite variable. Typical proscribed venues are schools, parks and day care centers, but there can be many others such as bus stops. Spatial aspects of these restrictions, such as how offender locations are geocoded and represented and how proscribed venues are delineated is analyzed. Specific details and theoretical concerns related to the many problematic issues with RSO restrictions is presented. In particular questions of their constitutionality and efficacy are raised. The paper concludes with a discussion of the implications of RSO restrictions for the discipline of geography in general and for the evolution of increasingly precise methods of spatial analysis in particular.  相似文献   
992.
工业化、城镇化、农业现代化、信息化、绿色化“五化”是社会现代化战略的重要支撑。“五化”协调定量评价是近年来一个研究热点。本文通过梳理和总结国内关于“五化”协调发展定量研究发现:①“五化”协调发展的内涵解读不一,评价时往往选择单指标,与综合指标差异很大。②权重计算以熵权法为主,层次分析法等主观评价方法较少,主客观评价结合更少。③协调水平的研究方法主要以耦合度、耦合协调度为主,其次为关系拟合与趋势预测法、DEA动态效率+HR模型、同步度模型等,并出现了系统性研究方法以及多种方法的交叉,研究方法的层次不断提高。④空间分析方法以空间分类与探索性空间数据分析为主,空间重心转移轨迹、空间格局的动态演进、空间趋势分析等研究方法逐渐出现。⑤时空分异的机理分析主要以影响因子解读与多元线性回归模型为主,空间滞后模型(SLM)、空间误差模型(SEM)、地理加权回归模型(GWR)等考虑空间因素的回归模型开始出现。但“化”的过程性、阶段性分析不足,“化”与“化”协调发展的转折点及转型机制分析不足。根据研究进展的评析,从研究范式、指标选择与权重计算、研究方法、空间分析技术、时空分异的机理解释等方面进行了反思,提出了加强“五化”协调发展的内在机理与评价维度分析、加强指标体系构建和权重设置的合理性研究、采用多元的“五化”协调度评价方法、加强空间分析技术的综合应用、促进定量解释与定性解释的结合等建议。  相似文献   
993.
This study describes the spatial and temporal variation of a drought index and makes inferences regarding the environmental factors that influence this variability in the Hengduan Mountains. A drought index is typically used to determine the moisture conditions and the magnitude of water deficiency in a given area. Based on data from 26 meteorological stations over the period 1960-2012, the spatial and temporal variations of the drought index were analyzed using a thin plate smoothing splines method that considered elevation as a covariate. The drought index was estimated based on the potential evapotranspiration (E0) as defined by the Penman Monteith model modified by FAO (1998). The results of the reported analysis showed that the drought index in the Hengduan Mountains has been decreasing since 1960 at a rate of -0.008/a. This represented a progressive shift from the "sub-humid" class, which typified the wider area in the Hengduan Mountains, toward the "humid" class, which appeared in the Hengduan Mountains areas. The drought index was relatively high in the north and low in the south and the variation of the drought index varied with seasons. The drought index showed increasing trends in summer and autumn and it is greater in autumn than in summer, while it showed a decreasing trend in spring and winter. Drought index is inversely proportional to the soil relative humidity and Normalized Difference Vegetation Index (NDVI).  相似文献   
994.
Fish maw(the dried swimbladders of fish) is ranked in the list of the four sea treasures in Chinese cuisine. Fish maw is mainly produced from croaker, which is the most highly priced. However, some of the fish maw being sold as croaker maw are in fact not from croaker, but from the Nile perch Lates niloticus. The present work determined and compared the proximate composition, amino acid and fatty acid composition of croaker Protonibea diacanthus maw and perch L. niloticus maw. The results indicated that both maws were high protein sources and low in fat content. The dominant amino acids in both maws were glycine, proline, glutamic acid, alanine and arginine. These amino acids constituted 66.2% and 66.4% of the total amino acids in P. diacanthus and L. niloticus, respectively. The ratio of FAA: TAA(functional amino acids: total amino acids) in both maws were 0.69. This is a good explanation for why fish maws have been widely utilized as a traditional tonic and remedy in Asia. Except valine and histidine, all the essential amino acid contents in P. diacanthus were higher than in L. niloticus. Moreover, croaker P. diacanthus maw contained more AA and DHA than perch L. niloticus maw, showing a higher ratio of n-3 / n-6, which is more desirable.  相似文献   
995.
当前普遍使用灰化法对地电化学泡塑样品进行预处理,但可能存在高温下某些元素(如Hg、As)挥发损失的缺点。本文选择了内蒙古洛恪顿热液型铅锌多金属矿床一条地电化学勘查剖面,开展灰化法及微波消解法处理地电化学泡塑样品的勘查效果对比研究,采用原子荧光光谱和高分辨电感耦合等离子体质谱测定其中的主要元素。结果表明:①对于Zn、Cu、Fe、La等十余种元素,两种处理方法取得的异常模式基本一致,可根据实际工作需求任选一种方法进行样品预处理;②对于Au、Pb等元素,微波消解法因为取样量小,可能存在较严重的样品均匀性、代表性及分析检出限等问题,应采用灰化法;③对于Hg,灰化法存在显著的元素损失,更适合采用微波消解法;④对于As,两种方法均存在较大问题,建议参考植物样品尝试使用硝酸及高氯酸直接溶解等方法进行预处理。  相似文献   
996.
首次介绍了国内自主研制的边界层微型火箭气象探空系统,系统包括火箭发射装置、探空仪、降落伞、地基接收设备和数据接收处理软件,其温度、湿度和气压测量采用数字式传感器,风速和风向由北斗/GPS全球定位信息获得。火箭升空至顶点后,将探空仪和降落伞从仪器舱弹出,在下降过程中测量大气的温度、湿度、气压和风速、风向等参数,通过无线发射机传送至地面接收机,由处理软件实现数据存储和参数分析。不同地区、不同气象条件下多次外场比较试验和实际应用结果表明,该系统性能稳定,探测技术指标和功能满足使用单位的设备研制要求,可应用于气象保障、大气探测、环境监测及海洋气象要素廓线的观测。  相似文献   
997.
An abundant and diversified assemblage of benthic fossils from the Ediacaran Doushantuo black shales in the Wenghui section of Guizhou Province contains two discoidal carbonaceous forms, Kullingia rotadiscopsis sp. nov. and Eoaequorea xingi gen. & sp. nov. The fossils have well-preserved concentric rings and radiating lines, and resemble many circular casts and moulds in Ediacaran clastic and carbonate rocks in the world, such as Aspidella, Ediacaria, Cyclomedusa, Eoporpita, Ovatoscutum, Spriggia and Kullingia. The Doushantuo carbonaceous macrofossils help us to inquire into the current functional identifications of circular disks as the holdfasts of unknown organism or scratch circles. Although there is not sufficient correspondence in morphology to warrant reinterpreting all previously described Kullingia and Aspidella form-genus-type structures, these carbonaceous compressions are prone to be the ancestor of pelagic jellyfish-like organisms with medusoid hydrozoan affinity.  相似文献   
998.
张玲  刘旭  姜義  纪永刚 《海洋科学》2016,40(6):133-138
本文对现有的高频地波雷达目标跟踪方法进行了概述,提出了一种地波雷达目标长时连续跟踪的方法,基本思想是:充分挖掘航迹弧段特征,基于特征对船只运动建模,并结合杂波背景进行融合决策。进一步,为了达到长时间连续跟踪的需求,借鉴深度学习的思想,利用新获取的弧段数据对算法估计结果不断递归校正,使得随着获取数据的增加跟踪越准确。该方法适用于杂波环境且在航道附近存在众多干扰船只的情况下对机动目标航迹的实时稳定跟踪,为高频地波雷达在复杂干扰环境下特定目标持续跟踪提供理论基础和方法指导,为充分发挥地波雷达在海上监视监测中的作用提供技术支撑。  相似文献   
999.
时晓露  马玲  刘瑱  朱炳文 《安徽地质》2016,26(2):158-160
测定岩石类样品中的Zr含量,酸溶经常结果偏低,碱溶通常较难获得较低的检出限。本文选取了不同岩性的岩石类国家标准物质GBW07104、GBW07106、GBW07107、GBW07114、GBW07835、GBW07836、GBW07837作为实验样品,分别采用酸溶后复溶、Na2O2碱熔、赶硅后Na2CO3和Na2B4O7三种前处理方法,对电感耦合等离子体质谱仪进行参数优化后上机测定,结果表明:对样品赶硅后加入少量Na2CO3和Na2B4O7混合试剂高温熔融处理岩石样品后,锆的测量值准确度高,而且获得了最低的检出限,同时缩短了方法流程,操作快捷。该方法更适用于各类岩石样品锆的测定。  相似文献   
1000.
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