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221.
Survival analysis: A survey 总被引:1,自引:0,他引:1
This paper is a survey of statistical methods used to analyze the length of time until a specified event occurs. These models have often been used to analyze the survival times (i.e., time until death) of medical patients, and so the term survival analysis is natural. In criminology, the main application of these models has been to analyze the time until recidivism, but many other applications are possible. The paper summarizes the statistical literature on survival analysis, and describes its applications in criminology. The methods are illustrated by an application to the prediction of time until recidivism for a sample of North Carolina prison releasees. 相似文献
222.
V. Auwaerter M. Grosse Perdekamp J. Kempf U. Schmidt W. Weinmann S. Pollak 《Forensic Science International Supplement Series》2007,170(2-3):139
A 23-year-old man was found on a raised hide in lying position, the head wrapped in a plastic bag connected with a helium gas cylinder by a polypropylene tube. The autopsy did not show any specific findings nor did the routine toxicological analysis reveal significant information regarding the cause of death (BAC 0.9 mg/g, diphenhydramine 0.81 μg/ml in heart serum). For the detection of helium in the lungs, gas samples from both lungs were collected by a method ensuring minimal dilution. Gas analyses were performed using a GC–MS with a split–splitless injector and a headspace syringe. As carrier gas the commonly used helium was replaced by nitrogen. Helium was found in clearly elevated concentrations in gas samples from both lungs. Therefore, suffocation by breathing helium enriched, and thus oxygen deficient atmosphere, can strongly be assumed as the cause of death. 相似文献
223.
Abstract: A new screening method for detecting gamma-hydroxybutyric acid (GHB) in drink matrices, using the IonSense, Inc. (Saugus, MA) direct analysis in real time (DART) ion source coupled to a JEOL exact mass time-of-flight mass spectrometer (AccuTOF), was validated and compared with the current screening methodology. The DART ion source allows for analysis of samples under ambient conditions with little to no sample preparation. Fifty drink specimens were spiked at levels of 1, 2, 3, and 4 mg/mL GHB, and analyzed on the AccuTOF-DART. Positive detection of GHB occurred for each of the samples at each concentration level, giving 100% accuracy for the samples tested. Twenty-five of the 50 drink specimens were spiked at 1 mg/mL GHB and tested using a color test known as the GHB Color Test #3. Only two of these 25 specimens tested positive for the presence of GHB, giving only 8% accuracy. Implementation of this new methodology as a screening tool for GHB analysis will quickly eliminate negative specimens allowing the examiner to focus analysis time on those that screened positive. 相似文献
224.
William Rhodes 《Journal of Quantitative Criminology》1986,2(2):113-137
Researchers are frequently interested in estimating the elapsed time until the occurrence of an event, such as an arrest following release from prison, dissolution of a marriage, and death following the onset of a disease. Estimation is often hindered by the occurrence of a competing event, which prevents the event of interest from being observed, and by limited follow-up periods. A parametric procedure developed in this paper is suitable for dealing with nonrepeatable competing events when the events are correlated and when independent righthand censoring also exists. Weak distributional assumptions are accommodated by using a Box-Cox transformation and by explicit modeling of heteroscedasticity. The procedure is applied to data pertaining to failure on probabation and parole. 相似文献
225.
The relation between recession and homicide is classic in the United States. This has been affirmed in the 1976 and 1984 Reports to the Joint Economic Committee (JEC) of the United States Congress. Recent analysis confirms the findings reported in both 1976 and 1984 and demonstrates that the influence of recession on homicide is greater than previously estimated. Differences in the 1976 and 1984 findings on homicide are related to differences in the hypotheses tested, as discussed in detail and highlighted in the 1984 report. JEC staff correctly interpreted and reported the 1984 findings. Reproduction of the 1984 homicide equation is straightforward, provided the same data and any of several standard estimation techniques are used. Evidence does not support any of Cook and Zarkin's claims in their critique of the 1984 homicide equation. The JEC report of 1984 used appropriate techniques in the attempt (a) to ensure that influences attributed to economic changes are not actually due to other social factors and (b) to minimize underspecification of models. 相似文献
226.
目的建立以固相萃取-高效液相色谱(SPE-HPLC)分析大鼠血浆中灭多威的方法。方法以空白大鼠血浆添加灭多威标准品及内标物,以SPE法对样品进行前处理,采用HPLC进行分析,考察仪器测试条件、特异性、回收率、灵敏度、精密度、准确度、线性关系、稳定性,并对方法进行优化。结果采用本文方法测得灭多威在血浆中的线性范围0.1-20μg/mL(r=0.9993,P〈0.001),血浆中的检测限0.03μg/mL(S/N≥3),日内、日间精密度的CV值分别在8.33%与11.11%以内,日内、日间准确度值分别在90%与120%之间,回收率值在88%±4.4%以上。结论所建方法实用、便捷,可对血浆中的灭多威进行定性定量地快速测定。 相似文献
227.
228.
GC/MS和GC法定性定量分析可卡因 总被引:1,自引:0,他引:1
目的建立用于可卡因案件检验鉴定的GC和GC/MS定性、定量分析方法。方法通过选择和优化,建立GC、GC/MS法检验可卡因的最佳分析条件;用分别含0.6mg/ml地西泮为内标的0.10、0.20、0.40、0.60、0.80、1.00、1.20mg/ml可卡因标准品乙醇液,考察线性范围和方法检测限。结果分析方法线性方程:GC/FID,Y=1.055X-0.0021,R2=0.9999,GC/NPD,Y=0.556X-0.0016,R2=0.9996;可卡因检测限:GC/FID法10ng,GC/NPD法2ng;分别以所建GC/FID、GC/NPD分析方法和内标法对案件中缴获的可卡因毒品进行定量分析,结果为72%±2.3%,且两方法定量重现性良好。结论本文所建方法可以用于可卡因涉毒案件的检验鉴定。 相似文献
229.
230.