Liquid-gas phase transition in nuclear multifragmentation

The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been a very important focal point of experimental endeavours in heavy ion collisions, in the last fifteen years. Simultaneously theoretical models have been developed to provide information about the equation of state and reaction mechanisms consistent with the experimental observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos corrected, minor text change

HIV Seroprevalence across the Rural/ Urban Continuum

While the first decade of the AIDS epidemic was characterized by high prevalence rates of AIDS infection in urban areas, there is increasing recognition of the spread of HIV into rural communities in the United States. Data from the Miami CARES cohort collected on 3,555 chronic drug users from 1988 to 1994 provide a unique opportunity to assess sociodemographic characteristics, drug-using behaviors and HIV risk behaviors related to HIV seropositivity in three communities across the rural-urban continuum: Miami, Florida; Belle Glade, Florida and Immokalee, Florida. The three very different communities studied demonstrate that HIV is no respecter of ecological site. The spread of HIV between areas and within areas is specifically correlated with the risk factors including injection drug use, use of crack cocaine, exchange of sex for money, and the rates for sexually transmitted diseases. All of these factors are shown to increase the risk of HIV so that the constellation of these practices helps determine the differential rates and spread of HIV in the three different areas. [Translations are provided in the International Abstracts Section of this issue.

Behavior Changes among Crack-Using Rural and Urban Women

This study compared rural and urban crack-using women and examined their responses to two interventions. A prospective cohort study design was employed to assess the effectiveness of standard and innovative HIV prevention interventions on 541 urban and 268 rural women in Florida. Generalized estimating equation analysis, accounting for repeated measures, found that for combined urban and rural samples, the innovative intervention was more effective than the standard for a number of drug and sexual risk behaviors. However, the analysis indicated no significant differences in intervention efficacy between rural and urban women. The results imply that there is a need for similar HIV prevention services in both areas. [Translations are provided in the International Abstracts Section of this issue.

Reducibility, thermal and mass scaling in angular correlations from multifragmentation reactions

The azimuthal angular correlations of light charged particles and light intermediate mass fragments emitted from the reaction 36Ar+197Au at E/A=50MeV are found to be reducible to the angular distributions of individual fragments. Thermal scaling is also observed in the coefficients of the angular correlations. Furthermore, the observed scaling with fragment mass seems to imply secondary emission from relatively small ( A≈15–30) primary fragments

Comparing injecting and non-injecting illicit opioid users in a multi-site Canadian sample (OPICAN cohort)

Illicit opioid use in Canada and elsewhere increasingly involves a variety of opioids and non-injection routes of administration. Injection and non-injection opioid users tend to differ in various key characteristics. From a public health perspective, non-injection routes of opioid use tend to be less harmful due to lesser morbidity and mortality risks. Our study compared current injectors (80%) and non-injectors (20%) in a multi-site sample of regular illicit opioid users from across Canada ('OPICAN' study). In bivariate analysis, injectors and non-injectors differed by prevalence in social and health characteristics as well as drug use. Logistic regression analysis identified city, drug use, housing status and mental health problems as independent predictors of injection status. Further analysis revealed that the majority of current non-injectors had an injection history. Our results reinforce the need to explore potential interventions aimed at preventing the transition from non-injectors to injecting, or facilitating the transition of injectors to non-injecting, as initiated in several other contexts