A View of Modern Human Origins from Y Chromosome Microsatellite Variation

The idea that all modern humans share a recent (within the last 150, 000 years) African origin has been proposed and supported on the basis of three observations. Most genetic loci examined to date have (1) shown greater diversity in African populations than in others, (2) placed the first branch between African and all non-African populations in phylogenetic trees, and (3) indicated recent dates for either the molecular coalescence (with the exception of some autosomal and X-chromosomal loci) or for the time of separation between African and non-African populations. We analyze variation at 10 Y chromosome microsatellite loci that were typed in 506 males representing 49 populations and every inhabited continent and find significantly greater Y chromosome diversity in Africa than elsewhere, find the first branch in phylogenetic trees of the continental populations to fall between African and all non-African populations, and date this branching with the (deltamu)2 distance measure to 5800-17,400 or 12,800-36,800 years BP depending on the mutation rate used. The magnitude of the excess Y chromosome diversity in African populations appears to result from a greater antiquity of African populations rather than a greater long-term effective population size. These observations are most consistent with a recent African origin for all modern humans.     

Correlates of Condom Use among Sex Workers and Their Boyfriends in Three West African Countries

The aim of this study was to identify correlates associated with condom use at last intercourse between sex workers (SW) and their boyfriends (BF). The sample was derived as a convenience sample recruited through existing HIV prevention organizations in Benin, Guinea and Senegal. The Theory of Planned Behavior served as the conceptual framework. A total of 406 individuals (220 SW and 186 BF) participated in the study. Socio-demographic, behavioral and psychological variables were collected through a face-to-face administered questionnaire. Condom use at last intercourse was significantly associated with intention and perceived control among SW as well as their BF. With respect to intention, perceived control, attitude and moral norm explained 82 and 74% of intention of SW and BF, respectively. These results suggest that promoting condom use among SW and BF should be based primarily on the development of personal ability to overcome obstacles to condom use.     

Alcohol Expectancies and Drinking Refusal Self‐Efficacy Mediate the Association of Impulsivity With Alcohol Misuse

Background: Recent work suggests that 2 biologically based traits convey risk for alcohol misuse: reward sensitivity/drive and (rash) impulsiveness. However, the cognitive mechanisms through which these traits convey risk are unclear. This study tested a model predicting that the risk conveyed by reward sensitivity is mediated by a learning bias for the reinforcing outcomes of alcohol consumption (i.e., positive alcohol expectancy). The model also proposed that the risk conveyed by rash impulsiveness (RI) is mediated by drinkers’ perceived ability to resist alcohol (i.e., drinking refusal self‐efficacy). Methods: Study 1 tested the model in a sample of young adults (n = 342). Study 2 tested the model in a sample of treatment‐seeking substance abusers (n = 121). All participants completed a battery of personality, cognitive, and alcohol use questionnaires and models were tested using structural equation modeling. Results: In both studies, the hypothesized model was found to provide a good fit to the data, and a better fit than alternative models. In both young adults and treatment‐seeking individuals, positive alcohol expectancy fully mediated the association between reward sensitivity and hazardous alcohol use. For treatment seekers, drinking refusal self‐efficacy fully mediated the association between RI and hazardous drinking. However, there was partial mediation in the young adult sample. Furthermore, neither trait was directly associated with the other cognitive mediator. Conclusions: The hypothesized model was confirmed on a large sample of young adults and replicated on a sample of treatment‐seeking substance abusers. Taken together, these findings shed further light on the mechanisms through which an impulsive temperament may convey risk for alcohol misuse.     

A comparison of the symptoms and short-term clinical course in inpatients with substance-induced psychosis and primary psychosis

Relatively little is known about the clinical course of symptoms in patients with a substance-induced psychosis (SIP) compared with those with a primary psychotic disorder (PPD). In this study, symptoms associated with psychosis were monitored across admission in two groups of patients: those with SIP (amphetamines or cannabis; n = 47) and those with PPD (n = 51). Sixty-two percent of patients were first admissions, 23% had one previous admission, and a further 14% had had two previous admissions. Symptoms were monitored using the Brief Psychiatric Rating Scale. Scores on the positive symptoms scale, negative symptoms scale, manic excitement, and negative mood were reported as was the extent of observed disturbed behavior at admission and then at Days 4/5, 8/9, 15/16, 22/23, 29/30, 36/37, 43/44, and 50/51. Patients with a SIP experienced more severe mania and disturbed behavior at admission than those with a PPD. However, these symptoms abated more rapidly for the SIP group during admission. Although positive symptom scores were equally high at admission for both groups, there was a more rapid abatement of these symptoms in the SIP group. Finally, negative symptoms were lower in the SIP group at admission and at Days 50/51, although the decline in symptoms was comparable in both groups.     

The Impact of Launching Surgery at the District Level in Niger

Background  

In 2005, the Ministry of Health in association with the Faculty of Medicine of Niamey decided to launch surgery at the district hospital (DH) level as part of the health strategy for the country. Surgical procedures were provided by general practitioners who received 12 months of training in basic surgery.     

An impedance sensor to monitor and control cerebral ventricular volume

This paper presents a sensor for monitoring and controlling the volume of the cerebrospinal fluid-filled ventricles of the brain. The measurement principle of the sensor exploits electrical conductivity differences between the cerebrospinal fluid and the brain tissue. The electrical contrast was validated using dog brain tissue. Experiments with prototype sensors accurately measured the volume content of elastically deformable membranes and gel phantoms with conductivity properties made to match human brain. The sensor was incorporated into a fully automatic feedback control system designed to maintain the ventricular volume at normal levels. The experimental conductivity properties were also used to assess the sensor performance in a simulated case of hydrocephalus. The computer analysis predicted voltage drops over the entire range of ventricular size changes with acceptable positional dependence of the sensor electrodes inside the ventricular space. These promising experimental and computational results of the novel impedance sensor with feedback may serve as the foundation for improved therapeutic options for hydrocephalic patients relying on volume sensing, monitoring or active feedback control.     

The reliability and validity of the Severity of Dependence Scale for detecting cannabis dependence in psychosis

AIMS: To determine the reliability and validity of the Severity of Dependence Scale (SDS) for detecting cannabis dependence in a large sample of in-patients with a schizophrenia spectrum disorder. DESIGN: Cross-sectional study. PARTICIPANTS: Participants were 153 in-patients with a schizophrenia spectrum disorder in Brisbane, Australia. MEASUREMENTS: Participants were administered the SDS for cannabis dependence in the past 12 months. The presence of Diagnostic and Statistical Manual Version-IV (DSM-IV) cannabis dependence in the previous 12 months was assessed using the Comprehensive International Diagnostic Interview (CIDI). FINDINGS: The SDS had high levels of internal consistency and strong construct and concurrent validity. Individuals with a score of >or = 2 on the SDS were nearly 30 times more likely to have DSM-IV cannabis dependence. The SDS was the strongest predictor of DSM-IV cannabis dependence after controlling for other predictor variables. CONCLUSIONS: The SDS is a brief, valid and reliable screen for cannabis dependence among people with psychosis.