Transcellular and extracellular impedances of the intact abdomen in putrefying rat cadavers

Total (Zt) and extracellular (Ze) abdominal impedances of putrefying rat cadavers, stored at 18.0±0.7°C, were measured at 50 kHz and at 1 kHz, respectively, during the first 7 days of death. Transcellular impedance was calculated from the measured values of Zt and Ze. Total impedance and Ze increased during the first day, and then decreased with increasing postmortem interval, while Zi remained unchanged during the first 3 days before increasing more than 4-fold between 3 and 7 days postmortem. These changes are consistent with net gain of electrolyte by the extracellular fluids and with degeneration of cell membranes which occur postmortem. It is concluded that, during putrefaction, Ze is a potentially more useful index of postmortem interval than Zt or Zi, and that measurement of total abdominal impedance at 50 kHz, rather than at 10 kHz, markedly improves the precision and accuracy of impedance measurement.     

Forecasting highway casualties: The British road safety act and a sense of déja vu

This paper reexamines the effect of the introduction of the British Road Safety Act of 1967. We construct a dynamic model relating monthly road casualties to road traffic, rainfall, and alcohol consumption, standardizing for the seasonality in the data. An intervention variable captures the effect of the Road Safety Act. The findings confirm Ross's earlier conclusion that the Road Safety Act significantly reduces casualties. However, we find that the Road Safety Act only accounts for 2.7 percent of the variance in road casualties, while miles-driven and rainfall account for 48.8 percent, and alcohol consumption explains 4.2 percent. Our model forecasts accurately for 24 months beyond December, 1972, the last month used for estimation.     

The influence of police interventions and alternative income sources on the dynamic process of choosing crime as a career

This paper demonstrates how a rational process of choice may be influenced by both deterrence forces and economic opportunities. This choice is modeled by a dynamic (Markov) process which captures self-sorting by youth among the categories of innocents, desisters, and persisters. in crime. A key to the results is the introduction of the perceived probability of punishment and its influence on the sorting process. The analysis shows how this force and the availability, or lack of, economic opportunities or income sources modify transition probabilities. The long-run consequences will be a larger subpopulation of individuals who have experimented with crime but subsequently revert to crime-free behavior and a smaller subpopulation of individuals who commit a greater share of crime. Empirical evidence is based on data from the New Youth Cohort of the National Longitudinal Surveys.