Prevalence and correlates of anal sex among secondary school students in Cape Town, South Africa

Research efforts have overlooked anal sex as a risk factor for adolescents’ acquisition of HIV despite the high rates of HIV among South African youth. Here, we report findings from a survey conducted in 2012 among secondary school youth, ages 16–24, in Cape Town. 937 adolescents completed a pencil-and-paper survey. Eleven and 31% of female and male youth, respectively, reported ever having anal sex. By comparison, 59% and 78% of female and male youth reported ever having vaginal sex. The percentage of youth reporting lifetime rates of anal sex increased with age: 32% of 20-to-24 year olds had anal sex compared to 16% of 16-to-17-year olds. When the sample was stratified by sex, this difference appeared to be driven by older male, but not female, sexual behavior. Despite noted differences in prevalence rates by sex, both boys and girls who had anal sex were more likely than their same-sex peers who had vaginal sex to report sexual coercion victimization and perpetration experiences and inconsistent condom use. Interestingly, some differences in HIV motivation, information, and behavioral skills were noted for youth who had vaginal sex versus youth who had never had sex; scores were largely similar for youth who had anal sex versus youth who had never had sex however. Together, these findings suggest that anal sex is not uncommon and may be an important marker for other HIV risk behaviors in at least one lower income South African community. Anal sex needs to be explicitly discussed in adolescent HIV prevention and healthy sexuality programing, incorporating age-relevant scenarios about negotiating condoms and other healthy relationship behaviors (e.g., refusing sex when it is not wanted)

Opportunities for technology-based HIV prevention programming among high school students in Cape Town, South Africa

One in three new cases of HIV in South Africa is among adolescents. Given that adolescents are particularly affected, scalable, and cost-effective prevention programs are urgently needed. This study aims to identify opportunities to integrate technology into youth HIV prevention efforts. In 2012, 1107 8th-11th graders completed a paper-and-pencil survey. Respondents were enrolled in one of three public high schools in Langa, a lower income community in Cape Town, South Africa. Eighty-nine percent of respondents have used text messaging (SMS) and 86% have gone online. If an HIV prevention program was offered online, 66% of youth would be somewhat or extremely likely to access it; slightly fewer (55%) felt the same about SMS-based programming. In comparison, 85% said they would be somewhat or extremely likely to access a school-based HIV prevention program. Interest in Internet- (60%) and SMS-based (54%) HIV prevention programming was similar for youth who had a self-appraised risk of HIV compared to youth who appraised their risk to be lower, as it was for youth who were tired of hearing messages about HIV prevention. Technology use is common - even among high school students who live in lower income communities. At the same time, these data reveal that it is not uncommon for youth to be tired of hearing messages about HIV prevention, and many of the typical topics key to HIV prevention have low interest levels among youth. HIV prevention researchers need to be mindful of the extent of existing programming that youth are exposed to. Technology-based programming may be especially amenable to meeting these requirements because of its novelty especially in developing countries, and because interactive functionality can be easily integrated into the program design. Given the preference for school and Internet-based programming, it seems that a hybrid approach is likely feasible and acceptable

Sensory Stimulation-Dependent Plasticity in the Cerebellar Cortex of Alert Mice

In vitro studies have supported the occurrence of cerebellar long-term depression (LTD), an interaction between the parallel fibers and Purkinje cells (PCs) that requires the combined activation of the parallel and climbing fibers. To demonstrate the existence of LTD in alert animals, we investigated the plasticity of local field potentials (LFPs) evoked by electrical stimulation of the whisker pad. The recorded LFP showed two major negative waves corresponding to trigeminal (broken into the N2 and N3 components) and cortical responses. PC unitary extracellular recording showed that N2 and N3 occurred concurrently with PC evoked simple spikes, followed by an evoked complex spike. Polarity inversion of the N3 component at the PC level and N3 amplitude reduction after electrical stimulation of the parallel fiber volley applied on the surface of the cerebellum 2 ms earlier strongly suggest that N3 was related to the parallel fiber–PC synapse activity. LFP measurements elicited by single whisker pad stimulus were performed before and after trains of electrical stimuli given at a frequency of 8 Hz for 10 min. We demonstrated that during this later situation, the stimulation of the PC by parallel and climbing fibers was reinforced. After 8-Hz stimulation, we observed long-term modifications (lasting at least 30 min) characterized by a specific decrease of the N3 amplitude accompanied by an increase of the N2 and N3 latency peaks. These plastic modifications indicated the existence of cerebellar LTD in alert animals involving both timing and synaptic modulations. These results corroborate the idea that LTD may underlie basic physiological functions related to calcium-dependent synaptic plasticity in the cerebellum

Serum from Calorie-Restricted Rats Activates Vascular Cell eNOS through Enhanced Insulin Signaling Mediated by Adiponectin

eNOS activation resulting in mitochondrial biogenesis is believed to play a central role in life span extension promoted by calorie restriction (CR). We investigated the mechanism of this activation by treating vascular cells with serum from CR rats and found increased Akt and eNOS phosphorylation, in addition to enhanced nitrite release. Inhibiting Akt phosphorylation or immunoprecipitating adiponectin (found in high quantities in CR serum) completely prevented the increment in nitrite release and eNOS activation. Overall, we demonstrate that adiponectin in the serum from CR animals increases NO• signaling by activating the insulin pathway. These results suggest this hormone may be a determinant regulator of the beneficial effects of CR

Nonspecific synaptic plasticity improves the recognition of sparse patterns degraded by local noise

Safaryan, K. et al. Nonspecific synaptic plasticity improves the recognition of sparse patterns degraded by local noise. Sci. Rep. 7, 46550; doi: 10.1038/srep46550 (2017). This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ © The Author(s) 2017.Many forms of synaptic plasticity require the local production of volatile or rapidly diffusing substances such as nitric oxide. The nonspecific plasticity these neuromodulators may induce at neighboring non-active synapses is thought to be detrimental for the specificity of memory storage. We show here that memory retrieval may benefit from this non-specific plasticity when the applied sparse binary input patterns are degraded by local noise. Simulations of a biophysically realistic model of a cerebellar Purkinje cell in a pattern recognition task show that, in the absence of noise, leakage of plasticity to adjacent synapses degrades the recognition of sparse static patterns. However, above a local noise level of 20 %, the model with nonspecific plasticity outperforms the standard, specific model. The gain in performance is greatest when the spatial distribution of noise in the input matches the range of diffusion-induced plasticity. Hence non-specific plasticity may offer a benefit in noisy environments or when the pressure to generalize is strong.Peer reviewe

Institutional factors that affect black South African students' perceptions of early childhood teacher education

Black students account for over 72% of enrolments in higher education, but only a small percentage of them choose Early Childhood Education (ECE) as a field of study and complete the qualification. The purpose of this study was to examine, from the perspective of black ECE students, why so few of them enrol in this particular programme at a historically white university. Through a qualitative, case study approach the reasons for the low enrolment and completion rates were investigated. Participants mentioned that recruitment for this programme, particularly in rural areas should be improved. They also pointed out the higher prestige of other career options, the linguistic challenges they face, the cost of university education and early teacher education in particular, as well as access to transport and resources as barriers to recruitment and retention. Their recommendations for higher enrolment rates included the use of black students to recruit in rural and in township areas, increased funding for bursaries, and more culturally sensitive pedagogies in early childhood teacher education