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31.
RAPD和ISSR分子标记检测大麻的遗传多样性初探   总被引:1,自引:0,他引:1  
目的利用随机扩增多态性DNA和简单序列重复区间扩增分子标记检测大麻遗传多样性,并探讨其在法医学中的应用价值。方法收集中国4省6个地区的100株大麻叶子样品,采用CTAB法提取基因组DNA,设计选择11个RAPD引物和13个ISSR引物,采用6%中性聚丙烯酰胺凝胶电泳-硝酸银染色法进行检测,根据出现的条带数目和片段大小等分析大麻的多样性。结果 11条RAPD引物扩增出的片段在200bp以上共52条,其中具有多态性的27条;ISSR引物扩增出126条,其中具有多态性的73条;多态性条带比率分别为51.9%和57.9%,其差异不具有统计学意义(P>0.05)。结论 RAPD和ISSR两种方法均可用于大麻遗传多样性分析,对检测毒品原植物的种类和来源地具有一定的应用前景。  相似文献   
32.
  总被引:1,自引:0,他引:1  
A skeletal assessment of ancestry relies on morphoscopic traits and skeletal measurements. Using a sample of American Black (n = 38), American White (n = 39), and Southwest Hispanics (n = 72), the present study investigates whether these data provide similar biological information and combines both data types into a single classification using a random forest model (RFM). Our results indicate that both data types provide similar information concerning the relationships among population groups. Also, by combining both in an RFM, the correct allocation of ancestry for an unknown cranium increases. The distribution of cross‐validated grouped cases correctly classified using discriminant analyses and RFMs ranges between 75.4% (discriminant function analysis, morphoscopic data only) and 89.6% (RFM). Unlike the traditional, experience‐based approach using morphoscopic traits, the inclusion of both data types in a single analysis is a quantifiable approach accounting for more variation within and between groups, reducing misclassification rates, and capturing aspects of cranial shape, size, and morphology.  相似文献   
33.
    
One of the most persistent public policy debates is over the aftermath of the foreclosure crisis and its continuing impact on housing markets. Distressed properties – including foreclosure and real estate-owned properties – tend to be sold at much lower prices than nearby comparable properties, often pulling down both surrounding property values and neighborhood morale. Recent findings show that these discounts for distressed properties are associated with various factors, but three important dimensions of these discounts remain relatively unexplored. First among these is the degree of variation in these discounts, even within the same regional market. Second is how discounts vary through the typical sequence of the distressed property transaction cycle. The final factor is the nature by which discounts vary according to the market participants – are the buyers/sellers individuals or institutions? This study examines these major factors affecting discounts, and estimates the spatially and sequentially heterogeneous discounts for distressed properties in the housing submarkets of Cuyahoga County, Ohio. Findings indicate that the discounts of distressed properties in the strong and weak submarkets substantially vary based on all three of these previously overlooked factors, yielding a more complex and nuanced housing context for practitioners and policymakers to consider.  相似文献   
34.
    
Wen Guo 《政策研究评论》2023,40(1):153-175
This article studies the formation of a local Creative Placemaking (CPM) policy network based on the Advocacy Coalition Framework (ACF) and social capital perspective of policy networks. This article hypothesizes that policy beliefs, policy learning, social capital, and the perceived risks induced by defections, as well as macro-level changes in the broader political and socio-economic system, influence partner selection in the local CPM policy networks. The study collected survey data from policy actors participating in the Franklinton CPM-catalyzed revitalization project in Columbus, Ohio. An exponential random graph model (ERGM) was applied to test the hypotheses. The findings partially support the hypotheses: policy learning, certain secondary policy beliefs, and risk perceptions of changes in economic and political factors are correlated with tie formation. The reciprocity-driven bonding structure underlies the Franklinton CPM policy network, suggesting that policy actors perceive the Franklinton CPM policy network as a high-defection-risk network. This study has implications for policy makers in designing engagement strategies to better involve stakeholders holding different beliefs and occupying different network positions.  相似文献   
35.
    
The forensics discipline of bloodstain pattern analysis plays an important role in crime scene analysis and reconstruction. One reconstruction question is whether the blood has been spattered via gunshot or blunt impact such as beating or stabbing. This paper proposes an automated framework to classify bloodstain spatter patterns generated under controlled conditions into either gunshot or blunt impact classes. Classification is performed using machine learning. The study is performed with 94 blood spatter patterns which are available as public data sets, designs a set of features with possible relevance to classification, and uses the random forests method to rank the most useful features and perform classification. The study shows that classification accuracy decreases with the increasing distance between the target surface collecting the stains and the blood source. Based on the data set used in this study, the model achieves 99% accuracy in classifying spatter patterns at distances of 30 cm, 93% accuracy at distances of 60 cm, and 86% accuracy at distances of 120 cm. Results with 10 additional backspatter patterns also show that the presence of muzzle gases can reduce classification accuracy.  相似文献   
36.
    
Soil, being diverse and ubiquitous, can potentially link a suspect or victim to a crime scene. Recently scientists have examined the microbial makeup of soil for determining its origin, and differentiating soil samples is well-established. However, when soil is transferred to evidence its microbial makeup may change over time, leading to false exclusions. In this research, “known” soils from diverse habitats were stored under controlled conditions, while evidence soils were aged on mock evidence. Limited quantities of soil were also assayed. Bacterial profiles were produced using next-generation sequencing of the 16S rRNA gene. Overall, known soils stored open at room temperature were more similar to evidence soils over time than were known soils stored bagged and/or frozen. Evidence soils, even as little as 1 mg, associated with the correct habitat 99% of the time, accentuating the importance of considering ex situ microbial changes in soil for its successful use as forensic evidence.  相似文献   
37.
    
Previous research has revealed the potential of soil bacterial profiling for forensic purposes; however, investigators have not thoroughly examined fluctuations in microbial profiles from soil aged on evidence. In this research, soils collected from multiple habitats were placed on evidence items and sampled over time, and then bacterial profiles were generated via next‐generation sequencing of the 16S rRNA locus. Bacterial abundance charts and nonmetric multidimensional scaling plots provided visual representation of bacterial profiles temporally, while supervised classification was used to statistically associate evidence to a source. The ex situ evidence soils displayed specific, consistent taxonomic changes as they aged, resulting in their drift in multidimensional space, but never toward a different habitat. Ninety‐five percent of the 364 evidentiary profiles statistically classified to the correct habitat, with misclassification generally stemming from evidence type and increased age. Ultimately, understanding bacterial changes that occur temporally in ex situ soils should enhance their use in forensic investigations.  相似文献   
38.
文章以大正时期著名的批判思想家长谷川如是闲写于1921年-1923年的中国游记《看过中国归来的男子的话》为主要的分析文本,通过阐释其文中“自我”与“他者”关照下所呈现的中国形象,重新检讨和评价其对中国的国家形成能力持否定态度,却又对中国社会的自治能力给予高度评价的中国观,力图为学界考察近代日本知识分子的中国观提供更为多元的视角.  相似文献   
39.
    
Interest group networks are crucial for understanding European Union (EU) integration, policymaking and interest representation. Yet, comparative analysis of interest organisation networks across EU policy areas is limited. This study provides the first large-scale investigation of interest group information networks across all EU policy domains. We argue that interest groups prioritise access to trustworthy and high-quality information coming from partners with shared policy goals. Thus, interest organisations form network ties with other organisations if the latter are from the same country, represent the same type of interest, or are policy insiders. The effect of these three factors varies across policy domains depending on the extent to which the institutional setting assures equal and broad organisational access to decision-making. Our empirical analysis operationalises information ties as Twitter-follower relationships among 7,388 interest organisations. In the first step of the analysis, we use Exponential Random Graph Models to examine tie formation in the full network and across 40 policy domains. We find strong but variable effects of country and interest type homophily and policy insiderness on the creation of network ties. In the second step, we examine how the effect of these three variables on tie formation varies with policy domain characteristics. We find that shared interest type and policy insiderness are less relevant for tie formation in (re-)distributive and especially regulatory policy domains characterised by more supranational decision-making. Sharing an interest type and being a policy insider matters more for tie formation in foreign and interior policies where decision-making is more intergovernmental. The effect of country homophily is less clearly related to policy type and decision-making mode. Our findings emphasise the importance of institutional and policy context in shaping interest group networks in the EU.  相似文献   
40.
正Hu Qingxue,40,a farm lad from Gu’an County in Hebei Province began in his teens to learn traditional musical notation.At 17 he enrolled in the classes of Zhang Benxing,a master of Jing Music at Beijing’s Zhihua Temple,which dates back to the early Ming Dynasty(1368-1644).Hu is now a government-recognized successor to this national intangible cultural heritage.  相似文献   
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