Objectives:To investigate whether the prevalence of HIV infection among young people, and sexual behaviours associated with increased HIV risk, are differentially distributed between students and ...those not attending school or college.Design:A random population sample of unmarried young people (916 males, 1003 females) aged 14–25 years from rural South Africa in 2001.Methods:Data on school attendance and HIV risk characteristics came from structured face-to-face interviews. HIV serostatus was assessed by oral fluid ELISA. Logistic regression models specified HIV serostatus and high-risk behaviours as outcome variables. The primary exposure was school attendance. Models were adjusted for potential confounders.Results:HIV knowledge, communication about sex and HIV testing were similarly distributed among students and non-students. The lifetime number of partners was lower for students of both sexes (adjusted odds ratio (aOR) for more than three partners for men 0.67; 95% CI 0.44 to 1.00; aOR for more than two partners for women 0.69; 95% CI 0.46 to 1.04). Among young women, fewer students reported having partners more than three years older than themselves (aOR 0.58; 95% CI 0.37 to 0.92), having sex more than five times with a partner (aOR 0.57; 95% CI 0.37 to 0.87) and unprotected intercourse during the past year (aOR 0.60; 95% CI 0.40 to 0.91). Male students were less likely to be HIV positive than non-students (aOR 0.21; 95% CI 0.06 to 0.71).Conclusions:Attending school was associated with lower-risk sexual behaviours and, among young men, lower HIV prevalence. Secondary school attendance may influence the structure of sexual networks and reduce HIV risk. Maximising school attendance may reduce HIV transmission among young people.
We describe the development of an efficient method for parameter estimation and ensemble forecasting in climate modelling. The technique is based on the ensemble Kalman filter and is several orders ...of magnitude more efficient than many others which have been previously used to address this problem. As well as being theoretically (near-)optimal, the method does not suffer from the `curse of dimensionality' and can comfortably handle multivariate parameter estimation. We demonstrate the potential of this method in identical twin testing with an intermediate complexity coupled AOGCM. The model's climatology is successfully tuned via the simultaneous estimation of 12 parameters. Several minor modifications arc described by which the method was adapted to a steady state (temporally averaged) case. The method is relatively simple to implement, and with only O(50) model runs required, we believe that optimal parameter estimation is now accessible even to computationally demanding models.
Eight earth system models of intermediate complexity (EMICs) are used to project climate change commitments for the recent Intergovernmental Panel on Climate Change’s (IPCC’s) Fourth Assessment ...Report (AR4). Simulations are run until the year 3000A.D. and extend substantially farther into the future than conceptually similar simulations with atmosphere–ocean general circulation models (AOGCMs) coupled to carbon cycle models. In this paper the following are investigated: 1) the climate change commitment in response to stabilized greenhouse gases and stabilized total radiative forcing, 2) the climate change commitment in response to earlier CO₂ emissions, and 3) emission trajectories for profiles leading to the stabilization of atmospheric CO₂ and their uncertainties due to carbon cycle processes. Results over the twenty-first century compare reasonably well with results from AOGCMs, and the suite of EMICs proves well suited to complement more complex models. Substantial climate change commitments for sea level rise and global mean surface temperature increase after a stabilization of atmospheric greenhouse gases and radiative forcing in the year 2100 are identified. The additional warming by the year 3000 is 0.6–1.6 K for the low-CO₂ IPCC Special Report on Emissions Scenarios (SRES) B1 scenario and 1.3–2.2 K for the high-CO₂ SRES A2 scenario. Correspondingly, the post-2100 thermal expansion commitment is 0.3–1.1 m for SRES B1 and 0.5–2.2 m for SRES A2. Sea level continues to rise due to thermal expansion for several centuries after CO₂ stabilization. In contrast, surface temperature changes slow down after a century. The meridional overturning circulation is weakened in all EMICs, but recovers to nearly initial values in all but one of the models after centuries for the scenarios considered. Emissions during the twenty-first century continue to impact atmospheric CO₂ and climate even at year 3000. All models find that most of the anthropogenic carbon emissions are eventually taken up by the ocean (49%–62%) in year 3000, and that a substantial fraction (15%–28%) is still airborne even 900 yr after carbon emissions have ceased. Future stabilization of atmospheric CO₂ and climate change requires a substantial reduction of CO₂ emissions below present levels in all EMICs. This reduction needs to be substantially larger if carbon cycle–climate feedbacks are accounted for or if terrestrial CO₂ fertilization is not operating. Large differences among EMICs are identified in both the response to increasing atmospheric CO₂ and the response to climate change. This highlights the need for improved representations of carbon cycle processes in these models apart from the sensitivity to climate change. Sensitivity simulations with one single EMIC indicate that both carbon cycle and climate sensitivity related uncertainties on projected allowable emissions are substantial.
Can we trust climate models? Hargreaves, J. C.; Annan, J. D.
Wiley interdisciplinary reviews. Climate change,
July/August 2014, Letnik:
5, Številka:
4
Journal Article
Recenzirano
Odprti dostop
What are the predictions of climate models, should we believe them, and are they falsifiable? Probably the most iconic and influential result arising from climate models is the prediction that, ...dependent on the rate of increase of CO2 emissions, global and annual mean temperature will rise by around 2–4°C over the 21st century. We argue that this result is indeed credible, as are the supplementary predictions that the land will on average warm by around 50% more than the oceans, high latitudes more than the tropics, and that the hydrological cycle will generally intensify. Beyond these and similar broad statements, however, we presently find little evidence of trustworthy predictions at fine spatial scale and annual to decadal timescale from climate models.
This article is categorized under:
Climate Models and Modeling > Knowledge Generation with Models
HIV infection and intimate-partner violence share a common risk environment in much of southern Africa. The aim of the Intervention with Microfinance for AIDS and Gender Equity (IMAGE) study was to ...assess a structural intervention that combined a microfinance programme with a gender and HIV training curriculum.
Villages in the rural Limpopo province of South Africa were pair-matched and randomly allocated to receive the intervention at study onset (intervention group, n=4) or 3 years later (comparison group, n=4). Loans were provided to poor women who enrolled in the intervention group. A participatory learning and action curriculum was integrated into loan meetings, which took place every 2 weeks. Both arms of the trial were divided into three groups: direct programme participants or matched controls (cohort one), randomly selected 14–35-year-old household co-residents (cohort two), and randomly selected community members (cohort three). Primary outcomes were experience of intimate-partner violence—either physical or sexual—in the past 12 months by a spouse or other sexual intimate (cohort one), unprotected sexual intercourse at last occurrence with a non-spousal partner in the past 12 months (cohorts two and three), and HIV incidence (cohort three). Analyses were done on a per-protocol basis. This trial is registered with
ClinicalTrials.gov, number
NCT00242957.
In cohort one, experience of intimate-partner violence was reduced by 55% (adjusted risk ratio aRR 0·45, 95% CI 0·23–0·91; adjusted risk difference −7·3%, −16·2 to 1·5). The intervention did not affect the rate of unprotected sexual intercourse with a non-spousal partner in cohort two (aRR 1·02, 0·85–1·23), and there was no effect on the rate of unprotected sexual intercourse at last occurrence with a non-spousal partner (0·89, 0·66–1·19) or HIV incidence (1·06, 0·66–1·69) in cohort three.
A combined microfinance and training intervention can lead to reductions in levels of intimate-partner violence in programme participants. Social and economic development interventions have the potential to alter risk environments for HIV and intimate-partner violence in southern Africa.
For decades, dental schools in the United States have endured a significant faculty shortage. Studies have determined that the top 2 sources of dental faculty are advanced education programs and ...private practice. Those who have completed both DDS and PhD training are considered prime candidates for dental faculty positions. However, there is no national database to track those trainees and no evidence to indicate that they entered academia upon graduation. The objective of this study was to assess outcomes of dental school–affiliated oral sciences PhD program enrollment, graduates, and placement between 1994 and 2016. Using the American Dental Association annual survey of advanced dental education programs not accredited by the Commission on Dental Accreditation and data obtained from 22 oral sciences PhD programs, we assessed student demographics, enrollment, graduation, and placement. Based on the data provided by program directors, the average new enrollment was 33, and graduation was 26 per year. A total of 605 graduated; 39 did not complete; and 168 were still in training. Among those 605 graduates, 211 were faculty in U.S. academic institutions, and 77 were faculty in foreign institutions. Given that vacant budgeted full-time faculty positions averaged 257 per year during this period, graduates from those oral sciences PhD programs who entered academia in the United States would have filled 9 (3.6%) vacant faculty positions per year. Therefore, PhD programs have consistently generated only a small pipeline of dental school faculty. Better mentoring to retain talent in academia is necessary. Stronger support and creative funding plans are essential to sustain the PhD program. Furthermore, the oral sciences PhD program database should be established and maintained by dental professional organizations to allow assessments of training models, trends of enrollment, graduation, and placement outcomes.
Abstract
Overprovision—healthcare whose harm exceeds its benefit—is of increasing concern in low- and middle-income countries, where the growth of the private-for-profit sector may amplify incentives ...for providing unnecessary care, and achieving universal health coverage will require efficient resource use. Measurement of overprovision has conceptual and practical challenges. We present a framework to conceptualize and measure overprovision, comparing for-profit and not-for-profit private outpatient facilities across 18 of mainland Tanzania’s 22 regions. We developed a novel conceptualization of three harms of overprovision: economic (waste of resources), public health (unnecessary use of antimicrobial agents risking development of resistant organisms) and clinical (high risk of harm to individual patients). Standardized patients (SPs) visited 227 health facilities (99 for-profit and 128 not-for-profit) between May 3 and June 12, 2018, completing 909 visits and presenting 4 cases: asthma, non-malarial febrile illness, tuberculosis and upper respiratory tract infection. Tests and treatments prescribed were categorized as necessary or unnecessary, and unnecessary care was classified by type of harm(s). Fifty-three percent of 1995 drugs prescribed and 43% of 891 tests ordered were unnecessary. At the patient-visit level, 81% of SPs received unnecessary care, 67% received care harmful to public health (prescription of unnecessary antibiotics or antimalarials) and 6% received clinically harmful care. Thirteen percent of SPs were prescribed an antibiotic defined by WHO as ‘Watch’ (high priority for antimicrobial stewardship). Although overprovision was common in all sectors and geographical regions, clinically harmful care was more likely in for-profit than faith-based facilities and less common in urban than rural areas. Overprovision was widespread in both for-profit and not-for-profit facilities, suggesting considerable waste in the private sector, not solely driven by profit. Unnecessary antibiotic or antimalarial prescriptions are of concern for the development of antimicrobial resistance. Option for policymakers to address overprovision includes the use of strategic purchasing arrangements, provider training and patient education.
The localization of substance P in brain regions that coordinate stress responses and receive convergent monoaminergic innervation suggested that substance P antagonists might have psychotherapeutic ...properties. Like clinically used antidepressant and anxiolytic drugs, substance P antagonists suppressed isolation-induced vocalizations in guinea pigs. In a placebo-controlled trial in patients with moderate to severe major depression, robust antidepressant effects of the substance P antagonist MK-869 were consistently observed. In preclinical studies, substance P antagonists did not interact with monoamine systems in the manner seen with established antidepressant drugs. These findings suggest that substance P may play an important role in psychiatric disorders.
In the present study we investigate the performance of climate models which contributed to the past 3 Intergovernmental Panel for Climate Change (IPCC) assessment reports for the Gangetic West Bengal ...region of east India (6° × 6°). Analysing present-day seasonal rainfall and temperature over the domain, we compare the results of the models (from the 6 modelling centres common to the second, third and fourth assessment reports—SAR, TAR and AR4, respectively) in order to judge to what extent these global models have improved on a regional scale. Metrics for model evaluation are not yet firmly established in the literature, so in this paper we compare and contrast the results from a number of different statistics used in previous studies. We also analyse the impact of topography on the results obtained for the AR4 models. We find that most models improved from SAR to AR4, although there is some variation in this result depending on seasons, variables and on which statistical methods are used in the analysis. The multi-model mean of the 6 models improves from SAR to TAR to AR4. The overall best performance in this region in the AR4 is the Japanese model, MIROC, but the best model in terms of improving skill from SAR to AR4 is the GFDL model from the United States. Correcting for errors in the model topographies produced an overall improvement of spatial patterns and error statistics, and greatly improves the performance of 1 model (CGCM) which has poor topography, but does not affect the ranking of the other models.
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