A Comparison of Thresholding Methods for Forensic Reconstruction Studies Using Fluorescent Powder Proxies for Trace Materials

Image segmentation is a fundamental precursor to quantitative image analysis. At present, no standardised methodology exists for segmenting images of fluorescent proxies for trace evidence. Experiments evaluated (i) whether manual segmentation is reproducible within and between examiners (with three participants repeatedly tracing three images) (ii) whether manually defining a threshold level offers accurate and reproducible results (with 20 examiners segmenting 10 images), and (iii) whether a global thresholding algorithm might perform with similar accuracy, while offering improved reproducibility and efficiency (16 algorithms tested). Statistically significant differences were seen between examiners’ traced outputs. Manually thresholding produced good accuracy on average (within ±1% of the expected values), but poor reproducibility (with multiple outliers). Three algorithms (Yen, MaxEntropy, and RenyiEntropy) offered similar accuracy, with improved reproducibility and efficiency. Together, these findings suggest that appropriate algorithms could perform thresholding tasks as part of a robust workflow for reconstruction studies employing fluorescent proxies for trace evidence.     

The influence of trust and collaboration with external partners on appropriability in open service firms

The Journal of Technology Transfer - This study explores how service firms in an open exchange of knowledge protect themselves against opportunistic behavior while trying to acquire some knowledge...     

“I Had a Confidence Epiphany!”: Obstacles to Combating Post-Identification Confidence Inflation

Research shows that eyewitnesses often become more confident with their selections from a lineup over time, a problem labeled "confidence inflation." Wells et al. (1998) Law and Human Behavior, 22, 603-647 suggested that eyewitnesses provide a confidence statement immediately following their selection to capture an unadulterated measure of confidence. Three experiments tested the effectiveness of introducing such a statement to combat the effects of confidence inflation on mock-juror judgments. All experiments provided evidence that the attributions participants formed about the eyewitness' confidence inflation differentially impacted their judgments. Although mock-jurors generally discredited eyewitnesses who showed confidence inflation and sometimes lowered probability of guilt ratings for the defendant, a clear exception occurred when mock-jurors attributed the inflation to an epiphany. Use of post-identification confidence statements to decrease the impact of confidence inflation in the courtroom may be insufficient.     

Partner Abuse and HIV Infection: Implications for Psychosocial Adjustment in African American Women

A prospective study of the effects of partner abuse among HIV-infected and noninfected African American women (N = 137) revealed that there were both concurrent and longitudinal effects of abuse on several indices of psychosocial adjustment. Specifically, higher levels of both verbal and physical abuse were found among the HIV-infected group. In addition, the effects of abuse on suicidal ideation were significantly stronger among the HIV-infected group (n = 53) than among their demographically similar noninfected counterparts (n = 84), resulting in significant HIV status by partner abuse interactions. The findings of this study advance our understanding of intimate relationships with regard to partner abuse by examining a group of women at high-risk for abuse, yet understudied in both the HIV/AIDS and relationship literatures.     

Suicidal contact gunshot wounds to the head with .38 Special Glaser Safety Slug ammunition

Glaser Safety Slug TM ammunition is a uniquely designed, essentially prefragmented ammunition. Tests performed by the U.S. Justice Department demonstrated that the ammunition possesses high kinetic energy, high relative incapacitation index (RII) and poses a very low risk to bystanders because of its total loss of kinetic energy in the target. Despite having been manufactured since 1974, no deaths from this ammunition have been previously reported. The authors herein describe the first three reported human deaths.     

Intense Preferences, Strong Beliefs and Democratic Decision-making

Some decisions require individuals to make judgements rather than to express preferences. Some conflicts of preference arise from different beliefs about the efficacy or propriety of a policy rather than from different wants. Should the 'intensity' with which a judgement is made, or a belief is held, figure in decision-making in the way that it should ideally influence decisions concerning wants? This article questions the relevance of intensity to matters of judgement and examines how far decision processes that are sensitive to different intensities of preference, such as pressure group activity, vote trading and point voting, are o pen to criticism for failing to discriminate between intense wants and strong beliefs.     

Comparison of ethanol concentrations in venous blood and end-expired breath during a controlled drinking study

Concentration-time profiles of ethanol were determined for venous whole blood and end-expired breath during a controlled drinking experiment in which healthy men (n=9) and women (n=9) drank 0.40-0.65 g ethanol per kg body weight in 20-30 min. Specimens of blood and breath were obtained for analysis of ethanol starting at 50-60 min post-dosing and then every 30-60 min for 3-6 h. This protocol furnished 130 blood-breath pairs for statistical evaluation. Blood-ethanol concentration (BAC, mg/g) was determined by headspace gas chromatography and breath-ethanol concentration (BrAC, mg/2l) was determined with a quantitative infrared analyzer (Intoxilyzer 5000S), which is the instrument currently used in Sweden for legal purposes. In 18 instances the Intoxilyzer 5000S gave readings of 0.00 mg/2l whereas the actual BAC was 0.08 mg/g on average (range 0.04-0.15 mg/g). The remaining 112 blood- and breath-alcohol measurements were highly correlated (r=0.97) and the regression relationship was BAC=0.10+0.91BrAC and the residual standard deviation (S.D.) was 0.042 mg/g (8.4%). The slope (0.91+/-0.0217) differed significantly from unity being 9% low and the intercept (0.10+/-0.0101) deviated from zero (t=10.2, P<0.001), indicating the presence of both proportional and constant bias, respectively. The mean bias (BAC - BrAC) was 0.068 mg/g and the 95% limits of agreement were -0.021 and 0.156 mg/g. The average BAC/BrAC ratio was 2448+/-540 (+/-S.D.) with a median of 2351 and 2.5th and 97.5th percentiles of 1836 and 4082. We found no significant gender-related differences in BAC/BrAC ratios, being 2553+/-576 for men and 2417+/-494 for women (t=1.34, P>0.05). The mean rate of ethanol disappearance from blood was 0.157+/-0.021 mg/(g per hour), which was very close to the elimination rate from breath of 0.161+/-0.021 mg/(2l per hour) (P>0.05). Breath-test results obtained with Intoxilyzer 5000S (mg/2l) were generally less than the coexisting concentrations of ethanol in venous blood (mg/g), which gives an advantage to the suspect who provides breath compared with blood in cases close to a threshold alcohol limit.