Survival analysis: A survey

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.     

Competing Risks, Persistence, and Desistance in Analyzing Recidivism

A statistical procedure is developed to analyze recidivism in samples whichare subject to the presence of desisters and to multiple modes ofreconviction. This allows for a more accurate study of individuals'transition and hazard in the type and timing of offenses following aspecific type of conviction. The use of a nonparametric approach forinvestigating failure in the presence of other acting causes is shown;initial estimators of the probabilities of reconviction for different typesof offenses are obtained, and the method can be used both to display thedata and to choose an appropriate parametric family for the survivaltimes. An exponential mixture model for competing risks is presented insuch a way that it allows us to adjust for concomitant variables and toassess their effects on the probabilities both of reconviction forpredetermined types of offenses and desistance and of the hazards ofreconviction; a method for assessing calibration of predicted survivalprobabilities is suggested. A 21-year follow-up of persons convicted ofindecent assault on a female in 1973 illustrates the methods; we find ahigh probability of sexual reconviction for individuals with previoussexual convictions and evidence of diversity and a raised hazard ofreconviction for young chronic offenders.     

A Preliminary Study on Vacuum Metal Deposition as a Standalone Method for Enhancement of Fingermarks on Ballistic Brass Materials

In order to assess the efficacy of vacuum metal deposition (VMD) as a technique to develop fingermarks on ballistic metallic surfaces, a preliminary study using six donors (three male & three female) was conducted. Using a sequential metal deposition process, two metal combinations were studied—gold/zinc and silver/zinc. Results indicate the potential of this technique, by developing identifiable fingermarks on brass metal disks aged from a few days up to more than a month old. As the development of fingermarks on fired (brass) cartridge cases is an area of interest, a further study was conducted where a total of 20 fingermarks were deposited on cases. After firing, second level fingermark characteristics were successfully observed on cartridge cases highlighting its potential as a fingermark enhancement method for ballistic brass materials. Further work is required to fully evaluate the VMD process and its reliability as a fingermark enhancing method on ballistic surfaces.     

Latent Fingermark Aging Patterns (Part IV): Ridge Width as One Indicator of Degradation

This fourth article of the series is taking an in‐depth analysis at the visible aging of latent fingermarks regarding changes in ridge widths over time. The objective is to quantify and statistically describe significant ridge size variations under controlled indoor conditions. The effect of three environmental variables are examined: type of secretion (sebaceous‐ and eccrine‐rich) and type of substrate (glass and polystyrene) when aged in three light conditions (direct natural light, shade, and dark). Prior to width measurements, fresh and aged fingermarks were powdered with titanium dioxide (TiO₂) and sequentially photographed at predetermined times over 6 months. Three independent observers measured the ridges from thirty predetermined locations using strategically placed intersecting lines on the print. Results indicate that fingermarks deposited on glass are more resilient to degradation compared with those deposited on plastic. The presence of direct natural light plays a negligible role on degradation compared to secretion and substrate types.     

Inherent Fluorescence Detection of Latent Fingermarks by Homemade Shortwave Ultraviolet Laser

Detection of latent fingermarks on various substrates is critical in crime investigations. Conventional chemical methods using reagents could contaminate or even destruct biological information of samples. Here, an optical method and successful case application of detecting latent fingermarks through long‐wave ultraviolet (UV) fluorescence (300–400 nm) by shortwave UV laser excitation is reported. Experimental results indicate that the recovery rate of the latent fingermarks on various paper items is in the range of 70–80% without chemical treatments. Moreover, the optical method allows for the preservation of samples for further examination, such as polymerase chain reaction (PCR) testing. The technique has also been successfully applied to a criminal case in identifying the suspect, which, to the best of our knowledge, has never been reported in real crime investigations. Therefore, such a method as UV‐excited UV fluorescence in detecting latent fingermarks may be better for examination in cases where biological information of samples is needed for consequent testing.     

Laser desorption/ionization time-of-flight mass spectrometry of triacylglycerols and other components in fingermark samples

The chemical composition of fingermarks could potentially be important for determining investigative leads, placing individuals at the time of a crime, and has applications as biomarkers of disease. Fingermark samples containing triacylglycerols (TAGs) and other components were analyzed using laser desorption/ionization (LDI) time-of-flight mass spectrometry (TOF MS). Only LDI appeared to be useful for this application while conventional matrix-assisted LDI-TOF MS was not. Tandem MS was used to identify/confirm selected TAGs. A limited gender comparison, based on a simple t-distribution and peaks intensities, indicated that two TAGs showed gender specificity at the 95% confidence level and two others at 97.5% confidence. Because gender-related TAGs differences were most often close to the standard deviation of the measurements, the majority of the TAGs showed no gender specificity. Thus, LDI-TOF MS is not a reliable indicator of gender based on fingermark analysis. Cosmetic ingredients present in some samples were identified.     

Moistened hands do not necessarily allude to high quality fingerprints: the relationship between palmar moisture and fingerprint donorship

We explored the quality distribution of ninhydrin-developed prints on A4 bond paper in two groups of individuals, in Israel and in India. While the quality distributions of the developed marks in both countries had some dissimilarities, both groups showed the expected bell-shape distribution, with the majority of the donors belonging to the central zone, defined as "average" or "good." Attempt was made to correlate between a physiological feature, palmar moisture, and the fingerprint donorship. As a rule, high fingermark quality could be associated with sweating hands, but there were individuals with moist palms whose fingermarks had a low score and vice versa. This finding supports the logical but hitherto unproven assumption that besides the amount of palmar sweat, the other physiological factor governing the prints' quality is the total amount of substrate, amino acids in this case, in the latent deposits, which depends on the substrate concentration in the sweat.     

New Thinking in Financial Market Regulation: Dismantling the “Split Share Structure” of Chinese Listed Companies

China’s distinctive set of stock market institutions was introduced in 1990. Among the characteristics of China’s stock markets was a strict separation between different categories of investors. Listed companies issued different categories of shares to state shareholders, domestic corporate investors, domestic individual investors, and foreign investors. By 2005, the barriers segmenting China’s stock market had been significantly relaxed. Domestic investors were allowed to purchase shares previously reserved for foreign investors, and approved foreign investors were allowed to purchase shares previously earmarked for domestic individuals. Nevertheless, a crucial barrier remained. An ongoing debate among Chinese academics, investors, and policy makers focused on how to resolve the “split share structure” (guquan fen zhi) in which a minority of shares were tradable while the majority of shares (namely those reserved for domestic corporate and state shareholders) were excluded from the market. The split share structure was blamed for distorting prices and inhibiting development of the stock market. This paper analyzes the policy adopted to address the split share structure. To what extent does this policy change reflect new thinking on the part of China’s market regulators? This paper argues that analysis of policy making in China’s capital markets can help to distinguish between two competing assessments of China’s political economy. One account sees China pursuing a gradualist strategy, slowly but steadily expanding the role of markets. Another account sees China trapped in a semi-marketized and increasingly corrupt development pattern. The implementation of the split share structure reform program provides evidence to support the gradualist account of incremental, but persistent, reform. Mary Comerford Cooper is an assistant professor in political science at the Ohio State University. Her recent research focuses on the politics of financial markets in China and Taiwan. Earlier versions of this paper were presented at the Comparative Politics Research Workshop/ Globalization, Institutions and Economic Security Workshop at Ohio State University in May 2007, and at the annual meeting of the Association for Chinese Political Studies in July 2007. I benefited greatly from the constructive and insightful comments of Bj?rn Alpermann, Melanie Barr, Jean-Marc Blanchard, Sarah Brooks, Joseph Fewsmith, Sujian Guo, Dane Imerman, Ryan Kennedy, Marcus Kurtz, Xiaoyu Pu, James Reilly, Alex Thompson, Daniel Verdier, Jianwei Wang, Alan Wiseman, Bin Yu, and an anonymous reviewer. I am also grateful for Lan Hu’s exceptional research assistance. All remaining flaws are purely my own.     

DNA recovery after sequential processing of latent fingerprints on copy paper

Forensic examiners must determine whether both latent fingerprint development and DNA profiling can be performed on the same area of an evidence item and, if only one is possible, which examination offers the best chance for identification. Latent fingerprints can be enhanced by targeting different components of fingerprint residues with sequential chemical treatments. This study investigated the effects of single-reagent and sequential latent fingerprint development processes on downstream DNA analysis to determine the point at which latent fingerprint development should be stopped to allow for DNA recovery. Latent fingerprints deposited on copy paper by one donor were developed using three sequential processes: 1,8-diazafluoren-9-one (DFO) → ninhydrin → physical developer (PD); 1,2-indanedione-zinc (IND-Zn) → ninhydrin → PD; and IND-Zn → ninhydrin → Oil Red O (ORO) → PD. Samples were examined after the addition of each chemical treatment. DNA was collected with cotton swabs, extracted, quantified, and amplified. DNA yields, peak heights, number of alleles obtained, and percentage of DNA profiles eligible for CODIS upload were examined. DNA profiles were obtained with varying degrees of success, depending on the number and type of treatments used for latent fingerprint development. The treatments that were found to be the least harmful to downstream DNA analysis were IND-Zn and IND-Zn/laser, and the most detrimental treatments were DFO, DFO/laser, and PD. In general, as the number of treatments increase, the opportunities for DNA loss or damage also increase, and it is preferable to use fewer treatments when developing latent fingerprints prior to downstream DNA processing.     

Use of styryl 11 and STaR 11 for the luminescence enhancement of cyanoacrylate-developed fingermarks in the visible and near-infrared regions

In current casework, most post-cyanoacrylate stains rely on luminescence emission in the visible region (400-700 nm). While traditional stains such as rhodamine 6G work well under most circumstances, some surfaces may generate background luminescence under the same conditions. Detection in the near-infrared region (NIR > 700 nm) has shown to be effective in minimizing the interferences from such surfaces. The laser dye styryl 11 generated strongly luminescent fingermarks when applied after cyanoacrylate fuming on all surfaces tested. When compared to rhodamine 6G, the dye was superior only when viewed in the NIR. Styryl 11 was subsequently combined with rhodamine 6G, and the mixed stain formulation (named StaR 11 by the authors) induced stronger luminescence compared with styryl 11 alone with an ability to visualize in both the visible and NIR regions. Reliable and consistent results were obtained when using either styryl 11 alone or the STaR 11 mixture. The enhancement achieved did not otherwise vary depending on the source of the fingermark secretions. With visualization possible in both the visible and NIR regions, the styryl 11/rhodamine 6G mixture showed significant potential as a post-cyanoacrylate stain.