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Objectives: New HIV infections remain higher in women than men in sub-Saharan Africa. Preexposure prophylaxis (PrEP) is an effective HIV prevention measure, currently prioritized for those at highest risk, such as female sex workers (FSWs), for whom it is most cost-effective. However, the greatest number of HIV infections in sub-Saharan Africa occurs in women in the general population. As countries consider wider PrEP scale-up, there is a need to weigh the population-level impact, cost, and relative cost-effectiveness to inform priority setting.Methods: We developed mathematical models of HIV risk to women and derived tools to highlight key considerations for PrEP programming. The models were fitted to South Africa, Zimbabwe, and Kenya, spanning a range of HIV burden in sub-Saharan Africa. The impact, cost, and cost-effectiveness of PrEP scale-up for adolescent girls and young women (AGYW), women 25 to 34 years old, and women 35 to 49 years old were assessed, accounting for differences in population sizes and the low program retention levels reported in demonstration projects.Results: Preexposure prophylaxis could avert substantially more infections a year among women in general population than among FSW. The greatest number of infections could be averted annually among AGYW in South Africa (24-fold that for FSW). In Zimbabwe, the greatest number of infections could be averted among women 25 to 34 years old (8-fold that for FSW); and in Kenya, similarly between AGYW and women 25 to 34 years old (3-fold that for FSW). However, the unit costs of PrEP delivery for AGYW, women 25 to 34 years old, and women 35 to 49 years old would have to reduce considerably (by 70.8%-91.0% across scenarios) for scale-up to these populations to be as cost-effective as for FSW.Conclusions: Preexposure prophylaxis has the potential to substantially reduce new HIV infections in HIV-endemic countries in sub-Saharan Africa. This will necessitate PrEP being made widely available beyond those at highest individual risk and continued integration into a range of national services and at community level to significantly bring down the costs and improve cost-effectiveness. [ABSTRACT FROM AUTHOR]

• The paper coupled photodegradation and endocrine disruption assay in environment risk assessment. • UV-A applied in photo degradation of steroidal hormones is not enough to reduce it from wastewater. • The photocatalytic process applying UV-C wavelength reduce levonorgestrel (LNG) from water but unknown photoproducts may arise. • Degraded fraction of LNG discharged to water affluent may produce more complex and diverse effects. • β-hCG hormone may be used in reproductive endocrine disruptor assessment for waterborne substances. The presence of levonorgestrel (LNG) in water bodies via direct discharge and human excretion has been reported worldwide, but its effects on the reproduction of aquatic species and humans are still unknown. Owing to its recalcitrant properties, LNG is not completely removed during wastewater treatment plants, and many species may be exposed to low traces of this compound from discharged effluents. Thus, in this study, a photocatalytic process for removing LNG along with screening of endocrine disruptor effects for risk assessment was applied. Although the removal rate of LNG by ultraviolet C (UV-C) radiation was >90%, reproductive toxicity testing using the BeWo cell line exposed to LNG and its degraded fraction showed the reduced production of basal human chorionic gonadotropin hormone (β-hCG) by more than 73%, from 8.90 mIU mL−1 to <2.39 mIU mL−1, with both LNG and the degraded fraction. β-hCG hormone has been implicated in the viability of trophoblastic cells during the first trimester of pregnancy; therefore, degraded fractions and waterborne LNG may affect reproduction in some aquatic species and humans with low level of exposure. [ABSTRACT FROM AUTHOR]

Abstract The distribution of trace ore elements in different paragenetic stages of pyrite has been documented for the first time in the sub-seafloor of the actively-forming TAG massive sulfide deposit. Trace element distributions have been determined by in-situ laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) of pyrite formed at different stages of mineralization, and at different temperatures constrained by previously published fluid inclusion analyses. The data reveal a strong dependence on paragenetic stage, with distinct low- and high-temperature enrichments. Porous pyrite (and marcasite) formed at low temperatures (<300 °C) in the outer margins of the deposit is enriched in As, Ag, Tl, Pb, Sb, Mo, W, Zn, Ga, Ge, Cd, In, Te, Au, Mn, V, and U. Coarse-grained pyrite formed at higher temperatures (>350 °C) at the base of the hydrothermal mound and in the stockwork zone is enriched in Co, Se, Bi, Cu, Ni, and Sn. A number of different sub-types of pyrite also have characteristic trace element signatures; e.g., the earliest pyrite formed at the highest temperatures is always enriched in Co and Se compared to later stages. Ablation profiles for Co, Se, and Ni are smooth and indicate that these elements are present mainly in lattice substitutions rather than as inclusions of other sulfides. Profiles for As, Sb, Tl, and Cu can be either irregular or smooth, indicating both lattice substitutions and inclusions. Lead and Ag have mostly smooth profiles, but because Pb cannot substitute directly into the pyrite lattice, it is interpreted to be present as homogeneously distributed micro- or nano-scale particles. The behavior of the different trace elements mainly reflects their aqueous speciation in the hydrothermal fluids at different temperatures, and for some elements like Co and Se, strong partitioning into the pyrite lattice at elevated temperatures. Adsorption onto pyrite surfaces controls the distribution of a number of redox-sensitive elements (i.e., Mo, V, Ni, U), particularly in the upper part of the mound which is infiltrated by cold seawater. Where micro- or nano-scale inclusions of chalcopyrite, sphalerite, galena, or sulfosalts are present, there is still a strong temperature dependence on the inclusion population (e.g., more abundant chalcopyrite in the highest-temperature pyrite), suggesting that the inclusions were co-precipitated with pyrite rather than overgrown. However, at the deposit scale, the trace element distributions are also strongly controlled by remobilization and chemical zone refining, as previously documented in bulk geochemical profiles. The results show that pyrite chemistry is a remarkably good model of the chemistry of the entire hydrothermal system. For many trace elements, the concentrations in pyrite are highly predictive in terms of the conditions of mineral formation over a wide range of temperatures, from the stockwork zone to the cooler outer margins of the deposit. Calculated minimum concentrations of the trace elements in the fluids needed to account for the observed concentrations in pyrite show good agreement with measured vent fluid concentrations, particularly Pb, As, Mo, Ag, and Tl. However, significantly higher concentrations are indicated for Co (and Se) than have been measured in sampled fluids, confirming the strong partitioning of these elements into high-temperature pyrite. [ABSTRACT FROM AUTHOR]

Introduction: Oral pre-exposure prophylaxis (PrEP) is a promising new prevention approach for those most at risk of HIV infection. However, there are concerns that behavioural disinhibition, specifically reductions in condom use, might limit PrEP's protective effect. This study uses the case of female sex workers (FSWs) in Johannesburg, South Africa, to assess whether decreased levels of condom use following the introduction of PrEP may limit HIV risk reduction. Methods: We developed a static model of HIV risk and compared HIV-risk estimates before and after the introduction of PrEP to determine the maximum tolerated reductions in condom use with regular partners and clients for HIV risk not to change. The model incorporated the effects of increased STI exposure owing to decreased condom use. Noting that condom use with regular partners is generally low, we also estimated the change in condom use tolerated with clients only, to still achieve 50 and 90% risk reduction on PrEP. The model was parameterized using data from Hillbrow, Johannesburg. Sensitivity analyses were performed to ascertain the robustness of our results. Results: Reductions in condom use could be tolerated by FSWs with lower baseline condom use (65%). For scenarios where 75% PrEP effectiveness is attained, 50% HIV-risk reduction on PrEP would be possible even with 100% reduction in condom use from consistent condom use as high as 70% with clients. Increased exposure to STIs through reductions in condom use had limited effect on the reductions in condom use tolerated for HIV risk not to increase on PrEP. Conclusions: PrEP is likely to be of benefit in reducing HIV risk, even if reductions in condom use do occur. Efforts to promote consistent condom use will be critical for FSWs with high initial levels of condom use, but with challenges in adhering to PrEP. [ABSTRACT FROM AUTHOR]

Introduction: Oral pre-exposure prophylaxis (PrEP) is a promising new prevention approach for those most at risk of HIV infection. However, there are concerns that behavioural disinhibition, specifically reductions in condom use, might limit PrEP's protective effect. This study uses the case of female sex workers (FSWs) in Johannesburg, South Africa, to assess whether decreased levels of condom use following the introduction of PrEP may limit HIV risk reduction. Methods: We developed a static model of HIV risk and compared HIV-risk estimates before and after the introduction of PrEP to determine the maximum tolerated reductions in condom use with regular partners and clients for HIV risk not to change. The model incorporated the effects of increased STI exposure owing to decreased condom use. Noting that condom use with regular partners is generally low, we also estimated the change in condom use tolerated with clients only, to still achieve 50 and 90% risk reduction on PrEP. The model was parameterized using data from Hillbrow, Johannesburg. Sensitivity analyses were performed to ascertain the robustness of our results. Results: Reductions in condom use could be tolerated by FSWs with lower baseline condom use (65%). For scenarios where 75% PrEP effectiveness is attained, 50% HIV-risk reduction on PrEP would be possible even with 100% reduction in condom use from consistent condom use as high as 70% with clients. Increased exposure to STIs through reductions in condom use had limited effect on the reductions in condom use tolerated for HIV risk not to increase on PrEP. Conclusions: PrEP is likely to be of benefit in reducing HIV risk, even if reductions in condom use do occur. Efforts to promote consistent condom use will be critical for FSWs with high initial levels of condom use, but with challenges in adhering to PrEP. [ABSTRACT FROM AUTHOR]

• Predictable trace element enrichments and depletions in the Reykjanes system. • Boiling exerts a major influence on the enrichment of metals. • High concentrations of Au and Ag and Pb indicate accumulation in reservoir fluids. • Three quarters of the metal budget is deposited at depth or in the upflow zone. Mineral precipitation in the seawater-dominated Reykjanes geothermal system on the Mid-Atlantic Ridge, Iceland is caused by abrupt, artificially induced, pressure and temperature changes as deep high-temperature liquids are drawn from reservoir rocks up through the geothermal wells. Sulfide scales within these wells represent a complete profile of mineral precipitation through a seafloor hydrothermal system, from the deep reservoir to the low-temperature silica-rich surface discharge. Mineral scales have formed under a range of conditions from high pressures and temperatures at depth (>2 km) to boiling conditions in the upflow zone and at the surface. Consistent trace element enrichments, similar to those in black smoker chimneys, are documented: Cu, Zn, Cd, Co, Te, V, Ni, Mo, W, Sn, Fe and S are enriched at higher pressures and temperatures in the deepest scales, Zn and Cu, Bi, Pb, Ag, As, Sb, Ga, Hg, Tl, U, and Th are enriched at lower temperatures and pressures nearer to the surface. A number of elements (e.g., Co, Se, Cd, Zn, Cu, and Au) are deposited in both high- and low-pressure scales, but are hosted by distinctly different minerals. Other trace elements, such as Pb, Ag, and Ga, are strongly partitioned into low-temperature minerals, such as galena (Pb, Ag) and clays (Ga). Boiling and destabilization of metal-bearing aqueous complexes are the dominant control on the deposition of most metals (particularly Au). Other metals (e.g., Cu and Se) may also have been transported in the vapor phase. Very large enrichments of Au, Ag and Pb in the scales (e.g., 948 ppm Au, 23,200 ppm Ag, and 18.8 wt.% Pb) versus average concentrations in black smoker chimneys likely reflect that some elements are preferentially deposited in boiling systems. A mass accumulation of 5.7 t/yr of massive sulfide was calculated for one high-temperature production well, equating to metal fluxes of 1.7 t/yr Zn, 0.3 t/yr Cu, 23 kg/yr Pb, 4.1 kg/yr Ag, and 0.5 kg/yr Au. At least three quarters of the major and trace element load is precipitated within the well before reaching the surface. We suggest that a similar proportion of metals may be deposited below the seafloor in submarine hydrothermal systems where significant boiling has occurred. Mass accumulation estimations over the lifetime of the Reykjanes system may indicate significant enrichment of Zn, Pb, Au, and Ag relative to both modern and ancient mafic-dominated seafloor massive sulfide deposits, and highlights the potential for metal enrichment and accumulation in the deep parts of geothermal systems. [ABSTRACT FROM AUTHOR]

This study examines a 65-ha botanically rich grassland mosaic with extensive woody encroachment to determine whether prairie habitat can be restored over a six-year period post treatment. A stratified sample design was utilized for vegetation monitoring. Two vegetation types, Prairie and Old Field, were identified from baseline differences in species composition. Additional plots also were established in relatively undegraded prairie habitat. This Reference Prairie provided a restoration benchmark for Transect Prairie and Old Field on transects. Management efforts resulted in a 95% reduction of woody stems, which were cut, piled, and burned on site. Cut stems were removed by hand in Reference Prairie; however, a compact track loader was used in remaining zones. Vegetation parameters of conservation interest based on species composition and diversity were utilized as predictor variables. We establish testable hypotheses and a statistical framework for evaluating mean differences and patterns of change among vegetation types. Reference Prairie retained baseline levels of floristic diversity and species integrity. However, it took six years for Transect Prairie to recover to baseline conditions. Old Field increased in native and non-native species richness leading to a floristic merger with recovering Transect Prairie; however, restoration goals fell short as Reference Prairie remained distinct in habitat quality from both successional community types. Our data suggest that population declines among resident species in Transect Prairie were a response to the more invasive management techniques. We recommend more gradual management practices to minimize the impacts of heavy equipment utilized for rapid and efficient treatment. [ABSTRACT FROM AUTHOR]