Reverse undercompressive shock structures in driven thin film flow

We show experimental evidence of a new structure involving an undercompressive and reverse undercompressive shock for draining films driven by a surface tension gradient against gravity. The reverse undercompressive shock is unstable to transverse perturbations while the leading undercompressive shock is stable. Depending on the pinch-off film thickness, as controlled by the meniscus, either a trailing rarefaction wave or a compressive shock separates from the reverse undercompressive shock

HIV prevention in Mexican schools: prospective randomised evaluation of intervention.

OBJECTIVE: To assess effects on condom use and other sexual behaviour of an HIV prevention programme at school that promotes the use of condoms with and without emergency contraception. DESIGN: Cluster randomised controlled trial. SETTING: 40 public high schools in the state of Morelos, Mexico. PARTICIPANTS: 10 954 first year high school students. INTERVENTION: Schools were randomised to one of three arms: an HIV prevention course that promoted condom use, the same course with emergency contraception as back-up, or the existing sex education course. Self administered anonymous questionnaires were completed at baseline, four months, and 16 months. Students at intervention schools received a 30 hour course (over 15 weeks) on HIV prevention and life skills, designed in accordance with guidelines of the joint United Nations programme on HIV/AIDS. Two extra hours of education on emergency contraception were given to students in the condom promotion with contraception arm. MAIN OUTCOME MEASURES: Primary outcome measure was reported condom use. Other outcomes were reported sexual activity; knowledge and attitudes about HIV and emergency contraception; and attitudes and confidence about condom use. RESULTS: Intervention did not affect reported condom use. Knowledge of HIV improved in both intervention arms and knowledge of emergency contraception improved in the condom promotion with contraception arm. Reported sexual behaviour was similar in the intervention arms and the control group. CONCLUSION: A rigorously designed, implemented, and evaluated HIV education course based in public high schools did not reduce risk behaviour, so such courses need to be redesigned and evaluated. Addition of emergency contraception did not decrease reported condom use or increase risky sexual behaviour but did increase reported use of emergency contraception

Cost of AIDS care in Mexico: what are its main individual predictors?

BACKGROUND: The Mexican government is offering universal access to antiretroviral (ARV) drugs. The cost of doing so, despite aggressive price negotiation with the pharmaceutical industry, remains high. Even with a low prevalence, about 150,000 Mexicans are estimated to be living with HIV and will require ARV treatment. Estimating the resources needed to fund this gap should consider how patient and provider characteristics affect health care costs. METHODS: Using a sample of patients from 11 facilities in three Mexican cities representing a large proportion of AIDS patients in the country, we developed a fixed-effect model, which by controlling the facilities and individual heterogeneity estimates predicted costs using patient demographic and socioeconomic characteristics as well as physician training. RESULTS: The estimated model explains about 45% of the variation in costs. Additional education is significantly and positively associated with cost. Increasing age is also associated with higher costs. CONCLUSIONS: Socioeconomic status and demographic characteristics explain an important proportion of variation in care costs for AIDS, despite AIDS being such a heterogeneous disease. Such characteristics will need to be taken into account when resource needs are estimated. A priority-setting process considering the principles of equity in the fair distribution of resources is needed to help reduce the social burden of HIV/AIDS in Mexico

Growth and Containment of a Hierarchical Criminal Network

We model the hierarchical evolution of an organized criminal network via antagonistic recruitment and pursuit processes. Within the recruitment phase, a criminal kingpin enlists new members into the network, who in turn seek out other affiliates. New recruits are linked to established criminals according to a probability distribution that depends on the current network structure. At the same time, law enforcement agents attempt to dismantle the growing organization using pursuit strategies that initiate on the lower level nodes and that unfold as self-avoiding random walks. The global details of the organization are unknown to law enforcement, who must explore the hierarchy node by node. We halt the pursuit when certain local criteria of the network are uncovered, encoding if and when an arrest is made; the criminal network is assumed to be eradicated if the kingpin is arrested. We first analyze recruitment and study the large scale properties of the growing network; later we add pursuit and use numerical simulations to study the eradication probability in the case of three pursuit strategies, the time to first eradication and related costs. Within the context of this model, we find that eradication becomes increasingly costly as the network increases in size and that the optimal way of arresting the kingpin is to intervene at the early stages of network formation. We discuss our results in the context of dark network disruption and their implications on possible law enforcement strategies.Comment: 16 pages, 11 Figures; New title; Updated figures with color scheme better suited for colorblind readers and for gray scale printin

Access to condoms for female sex workers in Andhra Pradesh.

BACKGROUND: Condoms are an essential part of comprehensive HIV prevention and care programmes. We report the accessibility of male condoms for female sex workers (FSWs) and the associated characteristics that may play a major role in determining access to condoms for FSWs. METHODS: Confidential interviews of 6509 street- and home-based FSWs in 13 districts of the Indian state of Andhra Pradesh provided data on the number of paying clients and various aspects of access to free condoms and purchase of condoms. Access to condoms was defined as having ever obtained condoms either through free distribution or through purchase. Multivariate analyses were done separately for street- and home-based FSWs to describe correlates of their access to condoms. The requirement of condoms was assessed based on the number of paying clients during the past 15 days. RESULTS: Data on condom access were available for 6465 (99.3%) FSWs. A total of 2850 (44.1%; 95% CI: 36.2%-52.0%) reported accessing free condoms ever and 2336 (36.1%; 95% CI: 30.6%-41.6%) had purchased condoms ever (not mutually exclusive). The primary sources for condoms were non-governmental organization facilities (73.8%) and pharmacies (79.7%) for free and purchased condoms, respectively. A total of 3510 (54.3%; 95% CI: 48.5%-60.1%) FSWs reported no access to free or purchased condoms during the past 15 days, and this no access was significantly higher for those > 30 years of age, with no schooling, street-based FSWs, and with no participation in a FSW support group (p < 0.001 for each in univariate analysis). Participation in a FSW support group was the main predictor of access to free condoms for both types of FSWs during the past 15 days with multivariate analysis. Condom requirements during the past 15 days were met for 67.5% of FSWs who had accessed only free condoms and for 33.8% of those who had accessed only purchased condoms. CONCLUSIONS: One-fourth of FSWs had never accessed condoms, and a little over half of those who had ever accessed reported no access during the past 15 days. Condom requirements were not met for three-fifths of the FSWs. HIV prevention programmes need to Increase access to free condoms for FSWs in Andhra Pradesh as access to condoms is a necessary prerequisite for condom use