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301.
STREET NETWORK STRUCTURE AND CRIME RISK: AN AGENT‐BASED INVESTIGATION OF THE ENCOUNTER AND ENCLOSURE HYPOTHESES
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Street networks shape day‐to‐day activities in complex ways, dictating where, when, and in what contexts potential victims, offenders, and crime preventers interact with one another. Identifying generalizable principles of such influence offers considerable utility to theorists, policy makers, and practitioners. Unfortunately, key difficulties associated with the observation of these interactions, and control of the settings within which they take place, limit traditional empirical approaches that aim to uncover mechanisms linking street network structure with crime risk. By drawing on parallel advances in the formal analyses of street networks and the computational modeling of crime events interactions, we present a theoretically informed and empirically validated agent‐based model of residential burglary that permits investigation of the relationship between street network structure and crime commission and prevention through guardianship. Through the use of this model, we explore the validity of competing theoretical accounts of street network permeability and crime risk—the encounter (eyes on the street) and enclosure (defensible space) hypotheses. The results of our analyses provide support for both hypotheses, but in doing so, they reveal that the relationship between street network permeability and crime is likely nonlinear. We discuss the ramifications of these findings for both criminological theory and crime prevention practice. 相似文献
302.
Quantitative Determination of Cannabinoids in Cannabis and Cannabis Products Using Ultra‐High‐Performance Supercritical Fluid Chromatography and Diode Array/Mass Spectrometric Detection
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Mei Wang Ph.D. Yan‐Hong Wang Ph.D. Bharathi Avula Ph.D. Mohamed M. Radwan Ph.D. Amira S. Wanas Ph.D. Zlatko Mehmedic M.Sc. John van Antwerp B.Sc. Mahmoud A. ElSohly Ph.D. Ikhlas A. Khan Ph.D. 《Journal of forensic sciences》2017,62(3):602-611
Ultra‐high‐performance supercritical fluid chromatography (UHPSFC ) is an efficient analytical technique and has not been fully employed for the analysis of cannabis. Here, a novel method was developed for the analysis of 30 cannabis plant extracts and preparations using UHPSFC /PDA ‐MS . Nine of the most abundant cannabinoids, viz . CBD , ?8‐THC , THCV , ?9‐THC , CBN , CBG , THCA ‐A, CBDA , and CBGA , were quantitatively determined (RSD s < 6.9%). Unlike GC methods, no derivatization or decarboxylation was required prior to UHPSFC analysis. The UHPSFC chromatographic separation of cannabinoids displayed an inverse elution order compared to UHPLC . Combining with PDA ‐MS , this orthogonality is valuable for discrimination of cannabinoids in complex matrices. The developed method was validated, and the quantification results were compared with a standard UHPLC method. The RSD s of these two methods were within ±13.0%. Finally, chemometric analysis including principal component analysis (PCA ) and partial least squares‐discriminant analysis (PLS ‐DA ) were used to differentiate between cannabis samples. 相似文献
303.
Chengzhi Li Ph.D. Dong Ma Ph.D. Kaifei Deng B.Sc. Yijiu Chen M.Sc. Ping Huang Ph.D. Zhenyuan Wang Ph.D. 《Journal of forensic sciences》2017,62(5):1345-1350
Estimating the postmortem interval (PMI) is very important in the forensic sciences. Although many approaches have been used for estimating the PMI, accurate PMI calculations are still difficult. In this study, four Sprague Dawley (SD) rats were sacrificed by suffocation, and muscle samples were collected by dissection at various time intervals (0, 48, 96, and 144 h) after death. All samples were probed using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to obtain molecular images and data for principal component analysis (PCA). The results showed that the peaks at m/z 1511, 1543, 1564, 1586 clearly decreased in intensity from 0 to 144 h postmortem and that the time groups were separated from each other on the PCA score plot. The prediction model showed high recognition capability (95.93%) and cross‐validation (83.72%). Our work suggests that MALDI‐TOF MS can be used to determine the PMI. 相似文献
304.
Feasibility of Canine Detection of Mass Storage Devices: A Study of Volatile Organic Compounds Emanating from Electronic Devices Using Solid Phase Microextraction
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Lauryn E. DeGreeff Ph.D. Michelle Cerreta Ph.D. Mark Rispoli J.D. 《Journal of forensic sciences》2017,62(6):1613-1616
Detection of canines are well‐known to be valuable in the location of contraband, such as explosives or narcotics. More recently, canines have been trained and utilized in the detection of concealed mass storage devices that might contain evidence of illegal activity such as child pornography. To lay the analytical foundation for this detection work, research was carried out to determine the volatile organic compounds associated with mass storage devices (MSD) that could be used by trained canines for detection. Headspace analysis of a variety of electronic devices was performed using solid phase microextraction (SPME) with gas chromatography/mass spectrometry (GC/MS). Analyses found several volatile compounds common to SIM and SD cards, as well as USB drives, including 2‐propenenitrile, styrene, isophorone, hydroxycyclohexyl phenyl ketone, and 2‐furanmethanol, tetrahydro. Results indicated that mass storage devices do have a characteristic odor profile making detection with minimal false alerts feasible for trained canines. 相似文献
305.
Qiang Yu 《Computer Law & Security Report》2017,33(1):103-111
China's merger enforcement agency approved the Google/Motorola merger with conditions. This pattern of approval is not in full accordance with that in other jurisdictions, including the United States and the European Union, which made unconditional approvals. This contradiction attracted ample criticism; some critics believe that China's policy is designed to protect domestic industry. In investigating the Chinese merger agency's decision and the basis for its decision making, this article finds that much of the criticism is groundless and misleading because the critics have failed to incorporate all elements of the global value chain of mobile intelligent terminals into their analyses. The investigation also shows that, although the decision makers are less experienced, their decisions are based on Chinese competition law and market realities. It is important for international firms to be aware of this pattern in merger analysis. 相似文献
306.
目的建立了一种高效液相色谱串联三重四极杆质谱同时测定体液中赛拉嗪及2,6-二甲基苯胺的分析方法。方法样品经HLB固相萃取柱提取净化,Waters Atlantis d C18色谱柱分离,正电离条件下进行选择监视扫描模式检测。结果方法的回收率为70.5%~79.8%,RSD为8.2%~10.5%。赛拉嗪及2,6-二甲基苯胺在血液和尿液中的检出限分别为0.4 ng/mL和0.3 ng/mL,定量限分别为1.2 ng/mL和1.0 ng/mL。结论本方法灵敏度高、特异性好、重现性好,适用于赛拉嗪中毒的血液和尿液检测。 相似文献
307.
308.
目的观察并分析肯定亲权关系的案件,探索STR基因座的突变规律。方法采用Goldeneye 20A试剂盒对20723例肯定亲权关系的案件筛选等位基因突变事件,统计各基因座的突变率和突变等位基因的来源、片段大小、突变步数及重复单位的增加或减少情况,分析突变相关因素的特点。结果 19个STR基因座共发现548例突变,观察到557个突变事件,基因座的突变率为0.07‰~2.23‰。父系突变与母系突变的比例为3.06∶1。突变以一步突变为主,增加与减少重复单位的情况相当;二步以上(含二步)突变更易出现重复单位减少。突变主要发生于中等位基因,重复单位增减比例相当,长等位基因突变中重复单位减少显著多于增加。父系突变出现重复单位增加与减少的比例相当,母系突变重复单位减少较增加多见。结论各基因座的突变率差异具有统计学意义,当出现1~2个基因座不符合遗传规律时,应当加测其他检测系统,并结合突变基因座的信息计算PI值,以进一步明确鉴定意见。 相似文献
309.
Supporting the positive development of a special needs child is especially challenging when parents have separated or divorced. Invariably, there is an increased need for collaborative co‐parenting wherein information is shared and intervention plans can be implemented effectively. In this article, the evolving literature on parental gatekeeping is applied to families with special needs children, as it offers a useful model for understanding the strengths and liabilities of co‐parenting relationships. We describe some of the typical and unique gatekeeping dynamics that occur when children suffer from developmental, physical, and/or psychiatric syndromes that require specific treatment and specialized parenting skills. Examples of both restrictive and facilitative gatekeeping are described as they manifest in these families. Implications for decision making are also discussed. 相似文献
310.