441 research outputs found
'It's because I like things… it's a status and he buys me airtime': exploring the role of transactional sex in young women's consumption patterns in rural South Africa (secondary findings from HPTN 068).
BACKGROUND: 'Transactional sex', defined as a non-marital, non-commercial sexual relationship in which money or material goods are exchanged for sex, is associated with young women's increased vulnerability to HIV infection. Existing research illustrates that the motivations for transactional sex are complex. The fulfilment of psycho-social needs such as the need to belong to a peer group are important factors underlying young women's desires to obtain certain consumption items and thus engage in transactional sex. METHODS: We use a mixed-methods approach to explore the relationship between transactional sex and consumption patterns among young women in rural Mpumalanga province, South Africa. In the secondary analysis of 693 sexually active young women, we use factor analysis to group the different consumption items and we use multivariable logistic regression to demonstrate the relationship between transactional sex and consumption patterns. The qualitative study uses five focus group discussions and 19 in-depth interviews to explore further young women's motivations for acquiring different consumption items. RESULTS: The quantitative results show that young women that engage in transactional sex have higher odds of consuming items for entertainment (e.g., movie tickets) than on practical items (e.g., food and groceries). The qualitative findings also revealed that young women's perceptions of items that were considered a 'need' were strongly influenced by peer pressure and a desire for improved status. Further, there was a perception that emerged from the qualitative data that relationships with sugar daddies offered a way to acquire consumer goods associated with a 'modern lifestyle', such as items for personal enhancement and entertainment. However, young women seem aware of the risks associated with such relationships. More importantly, they also develop relationship with partners of similar age, albeit with the continued expectation of material exchange, despite engaging in the relationship for love. CONCLUSION: This study shows that young women are willing to take certain risks in order to have a degree of financial independence. Interventions that provide alternative methods of attaining this independence, such as the provision of cash transfers may have potential in preventing them from engaging in transactional relationships. Further, the psycho-social reasons that drive young women's motivations for consumption items resulting in risky sexual behaviours need to be better understood
Evaluating simplified chemical mechanisms within present-day simulations of the Community Earth System Model version 1.2 with CAM4 (CESM1.2 CAM-chem): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast chemistry
While state-of-the-art complex chemical mechanisms expand our understanding
of atmospheric chemistry, their sheer size and computational requirements
often limit simulations to short lengths or ensembles to only a few members.
Here we present and compare three 25-year present-day offline simulations
with chemical mechanisms of different levels of complexity using the
Community Earth System Model (CESM) Version 1.2 CAM-chem (CAM4): the Model
for Ozone and Related Chemical Tracers, version 4 (MOZART-4) mechanism, the
Reduced Hydrocarbon mechanism, and the Super-Fast mechanism. We show that,
for most regions and time periods, differences in simulated ozone chemistry
between these three mechanisms are smaller than the model–observation
differences themselves. The MOZART-4 mechanism and the Reduced Hydrocarbon
are in close agreement in their representation of ozone throughout the
troposphere during all time periods (annual, seasonal, and diurnal). While
the Super-Fast mechanism tends to have higher simulated ozone variability and
differs from the MOZART-4 mechanism over regions of high biogenic emissions,
it is surprisingly capable of simulating ozone adequately given its
simplicity. We explore the trade-offs between chemical mechanism complexity
and computational cost by identifying regions where the simpler mechanisms
are comparable to the MOZART-4 mechanism and regions where they are not. The
Super-Fast mechanism is 3 times as fast as the MOZART-4 mechanism, which
allows for longer simulations or ensembles with more members that may not be
feasible with the MOZART-4 mechanism given limited computational resources.</p
Understanding mercury oxidation and air–snow exchange on the East Antarctic Plateau: a modeling study
Distinct diurnal and seasonal variations of mercury (Hg) have been observed
in near-surface air at Concordia Station on the East Antarctic Plateau, but
the processes controlling these characteristics are not well understood.
Here, we use a box model to interpret the Hg0 (gaseous elemental
mercury) measurements in thes year 2013. The model includes atmospheric Hg0
oxidation (by OH, O3, or bromine), surface snow HgII (oxidized
mercury) reduction, and air–snow exchange, and is driven by meteorological
fields from a regional climate model. The simulations suggest that a
photochemically driven mercury diurnal cycle occurs at the air–snow interface
in austral summer. The fast oxidation of Hg0 in summer may be provided
by a two-step bromine-initiated scheme, which is favored by low temperature
and high nitrogen oxides at Concordia. The summertime diurnal variations of
Hg0 (peaking during daytime) may be confined within several tens of
meters above the snow surface and affected by changing mixed layer depths.
Snow re-emission of Hg0 is mainly driven by photoreduction of snow
HgII in summer. Intermittent warming events and a hypothesized reduction
of HgII occurring in snow in the dark may be important processes
controlling the mercury variations in the non-summer period, although their
relative importance is uncertain. The Br-initiated oxidation of Hg0 is
expected to be slower at Summit Station in Greenland than at Concordia (due to their
difference in temperature and levels of nitrogen oxides and ozone), which may
contribute to the observed differences in the summertime diurnal variations
of Hg0 between these two polar inland stations.</p
Men’s perspectives on the impact of female-directed cash transfers on gender relations: Findings from the HPTN 068 qualitative study
Background HIV is an inherently gendered disease in eastern and southern Africa, not only because more women than men are infected, but also because socially constructed gender norms work to increase women’s HIV-infection risk. The provision of cash transfers to young women alone in such a context adds another dimension to already existing complex social relations where patriarchal values are entrenched, gender inequality is the norm, and violence against women and girls is pervasive. It raises concerns about complicating young women’s relationships with their male partners or possibly even setting them up for more violence. In our attempt to understand how cash transfers influence social relations in the context of a trial among young women in South Africa, we used qualitative data collected during the trial to explore men’s perceptions of the impact of cash transfers on male-female relationships, both intimate and platonic, peer relationships. Method Between April 2012 and August 2015, we conducted focus group discussions (n = 12) and interviews (n = 20) with the male peers and intimate partners of young women aged 13–20 years, who were participating in a phase III randomised controlled trial of CTs for HIV prevention in Mpumalanga, South Africa. A thematic content analysis approach was used to analyse the data. The codebook was developed on the basis of the topic guides, with additional codes added inductively as they emerged from the data. Results Intimate partners were older (range 20–32 years) and more likely to be working than the male peers. Both intimate partners and male peers were supportive of the CT trial targeting young women; younger peers however expressed some concerns that the money might diminish their power and status in relationships. HIV testing requirements associated with the trial appeared to have improved communication about sex and HIV in intimate relationships, with some women even encouraging their partners to go for an HIV test. Conclusion CTs provide AGYW with a measure of autonomy and power to contribute in their gendered relationships, albeit in limited ways. However, there is potential for CTs to have a negative impact on male-female relationships if the cash received by AGYW is equal to or greater than the income earned by their male counterparts or sexual partners
Oxidation of mercury by bromine in the subtropical Pacific free troposphere
Mercury is a global toxin that can be introduced to ecosystems through atmospheric deposition. Mercury oxidation is thought to occur in the free troposphere by bromine radicals, but direct observational evidence for this process is currently unavailable. During the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks campaign, we measured enhanced oxidized mercury and bromine monoxide in a free tropospheric air mass over Texas. We use trace gas measurements, air mass back trajectories, and a chemical box model to confirm the origin and chemical history of the sampled air mass. We find the presence of elevated oxidized mercury to be consistent with oxidation of elemental mercury by bromine atoms in this subsiding upper tropospheric air mass within the subtropical Pacific High, where dry atmospheric conditions are conducive to oxidized mercury accumulation. Our results support the role of bromine as the dominant oxidant of mercury in the upper troposphereNational Science Foundation (U.S.) (Grants 121701 and, 1215712
Genetic variation at mouse and human ribosomal DNA influences associated epigenetic states
Background: Ribosomal DNA (rDNA) displays substantial inter-individual genetic variation in human and mouse. A systematic analysis of how this variation impacts epigenetic states and expression of the rDNA has thus far not been performed.
Results: Using a combination of long- and short-read sequencing, we establish that 45S rDNA units in the C57BL/6J mouse strain exist as distinct genetic haplotypes that influence the epigenetic state and transcriptional output of any given unit. DNA methylation dynamics at these haplotypes are dichotomous and life-stage specific: at one haplotype, the DNA methylation state is sensitive to the in utero environment, but refractory to post-weaning influences, whereas other haplotypes entropically gain DNA methylation during aging only. On the other hand, individual rDNA units in human show limited evidence of genetic haplotypes, and hence little discernible correlation between genetic and epigenetic states. However, in both species, adjacent units show similar epigenetic profiles, and the overall epigenetic state at rDNA is strongly positively correlated with the total rDNA copy number. Analysis of different mouse inbred strains reveals that in some strains, such as 129S1/SvImJ, the rDNA copy number is only approximately 150 copies per diploid genome and DNA methylation levels are < 5%.
Conclusions: Our work demonstrates that rDNA-associated genetic variation has a considerable influence on rDNA epigenetic state and consequently rRNA expression outcomes. In the future, it will be important to consider the impact of inter-individual rDNA (epi)genetic variation on mammalian phenotypes and diseases
'It’s because I like things… it’s a status and he buys me airtime': exploring the role of transactional sex in young women’s consumption patterns in rural South Africa (secondary findings from HPTN 068)
Abstract: Background ‘Transactional sex’, defined as a non-marital, non-commercial sexual relationship in which money or material goods are exchanged for sex, is associated with young women’s increased vulnerability to HIV infection. Existing research illustrates that the motivations for transactional sex are complex. The fulfilment of psycho-social needs such as the need to belong to a peer group are important factors underlying young women’s desires to obtain certain consumption items and thus engage in transactional sex. Methods We use a mixed-methods approach to explore the relationship between transactional sex and consumption patterns among young women in rural Mpumalanga province, South Africa. In the secondary analysis of 693 sexually active young women, we use factor analysis to group the different consumption items and we use multivariable logistic regression to demonstrate the relationship between transactional sex and consumption patterns. The qualitative study uses five focus group discussions and 19 in-depth interviews to explore further young women’s motivations for acquiring different consumption items. Results The quantitative results show that young women that engage in transactional sex have higher odds of consuming items for entertainment (e.g., movie tickets) than on practical items (e.g., food and groceries). The qualitative findings also revealed that young women’s perceptions of items that were considered a ‘need’ were strongly influenced by peer pressure and a desire for improved status. Further, there was a perception that emerged from the qualitative data that relationships with sugar daddies offered a way to acquire consumer goods associated with a ‘modern lifestyle’, such as items for personal enhancement and entertainment. However, young women seem aware of the risks associated with such relationships. More importantly, they also develop relationship with partners of similar age, albeit with the continued expectation of material exchange, despite engaging in the relationship for love. Conclusion This study shows that young women are willing to take certain risks in order to have a degree of financial independence. Interventions that provide alternative methods of attaining this independence, such as the provision of cash transfers may have potential in preventing them from engaging in transactional relationships. Further, the psycho-social reasons that drive young women’s motivations for consumption items resulting in risky sexual behaviours need to be better understood
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