Sexing of human clavicles using length and circumference measurements

Measurement of clavicular length and circumference, and computation of clavicular robustness and length-circumference product from 724 autopsied adults of known age, sex, and body length between the ages of 15 and 96 years produced useful sex-predictive values. This predominantly North American white population contained 560 males and 164 females with intact, nondeformed clavicles. Clavicle length and circumference and particularly their product have been found useful in sexing, but robustness as a single trait has not. Despite a significant overlap of male and female values, the use of single cutoff values allowed correct sex assignment of up to 93% of the entire study population, including 94% of males and 89% of females. The ratios of body length to clavicle circumference and to clavicle length are on average greater in women than in men. The former ratio yields male predictive values greater than 95% for those individuals with ratios falling below the cutoff value of 43, whereas the latter ratio is a relatively poor sex predictor.     

Peak blood-ethanol concentration and the time of its occurrence after rapid drinking on an empty stomach

Healthy men, 20 to 60 years old, drank a moderate dose of ethanol in the morning after an overnight fast. They consumed either neat whisky in amounts corresponding to 0.34, 0.51, 0.68, 0.85, or 1.02 g of ethanol per kilogram of body weight or 0.80 g/kg ethanol solvent diluted with orange juice. The peak blood-ethanol concentration (BEC) increased with the dose administered, but the time required to reach the peak was not markedly influenced over the range of doses studied. At a dose of 0.68 g/kg, the peak BEC ranged from 52 to 136 mg/dL (N = 83), and slow absorption (a late-occurring peak) produced a lower peak BEC. The peak BEC was reached between 0 and 45 min for 77% of the subjects (N = 152) and between 0 and 75 min for 97% of them. The time of peaking in venous blood occurred, on average, 10 min later than in capillary (fingertip) blood although the peak BEC was not appreciably different; the mean venous BEC was 97.0 mg/dL (range, 76 to 112 mg/dL), and the mean capillary BEC was 99.6 mg/dL (range, 75 to 123 mg/dL). When subjects drank 0.80 g/kg ethanol diluted with orange juice over 30 min, the average BEC increment between the end of drinking and the peak was 33 mg/dL (range, 0 to 58 mg/dL). The rate of absorption of ethanol was 1.78 mg/dL/min (range, 0.52 to 4.8 mg/dL/min), and the peak BEC occurred within 60 min after the end of drinking in 92% of the trials. The largest BEC increment (mean, 21 mg/dL; range, 0 to 44 mg/dL) was seen during the first 15 min after the drinking period.     

Implications of trombiculid mite bites: report of a case and submission of evidence in a murder trial

Bites of Trombiculid mites implicated a suspect during a homicide investigation. Clinical documentation of the bites, correlation with entomological studies, and submission of evidence at trial are reported. Insects that have a discrete geographic distribution and leave bites of a characteristic nature may have important forensic science implications.     

Risk Aversion, Liability Rules, and Safety

This paper investigates the performance of liability rules in two-party stochastic externality problems where negotiations are feasible and side payments are based on the realized level of externalities. Results show that an increase in polluter liability does not necessarily increase safety or efficiency in cases where the polluter is risk neutral. Complete polluter liability is found to yield Pareto optimality. When either party is risk averse, an increase in polluter liability may sometimes reduce safety and efficiency. If the polluter is risk neutral and the victim is risk averse, Pareto optimality is only achieved by assigning full liability on the polluter, i.e. giving the victim complete property rights to a clean environment. If the polluter is risk averse and the victim is risk neutral, no level of polluter liability is optimal. In this case, optimality can only be achieved through a contract on abatement activities, such that the risk-averse polluter receives a guaranteed payment regardless of the stochastic outcome.     

Characterization of human DNA in environmental samples

Environmental samples from indoor surfaces can be confounded by dust, which is composed largely of human skin cells and has been documented to contain roughly tens of micrograms of total DNA per gram of dust. This study complements previous published work by providing estimates of the quantity of amplifiable human DNA found in environmental samples from a typical indoor environment, categorized by the intensity of human traffic and visible quantity of dust. Dust was collected by surface swabbing standard 576 cm² areas in eight locations, and evaluated for total DNA quantity, presence of human DNA (mitochondrial and nuclear loci using conventional PCR), quantity of human nuclear DNA using quantitative PCR, and STR analysis. The total DNA content of 36 dust samples ranged from 9 to 28 ng/cm², and contained 0.2–1.1 pg/cm² of human DNA. Overall, human DNA was detected in 97% of 36 dust samples and 61% of samples yielded allele distributions of varying degrees of complexity when subjected to STR analysis. The implications of this study are twofold. First, the presence of dust in evidence can be a significant contamination source in forensic investigations because the human DNA component is of sufficient quality and quantity to produce allele calls in STR analysis. This can be effectively managed by implementing stringent protocols for collection and analysis of potential biological samples. A second implication is the use of dust as a source of evidence for identification of inhabitants within a defined location. In the latter case, a number of additional studies would be necessary to identify relevant pretreatments for environmental dust samples and to develop the necessary deconvolution techniques to separate the composite genotypes obtained.