Addressing legal and policy barriers to male circumcision for adolescent boys in South Africa

With millions of adolescents becoming infected with HIV globally, it is essential that barriers to much-needed interventions are reduced for at-risk adolescents. In this article we review the legal and policy framework in South Africa for adolescent access to male circumcision. We are of the view that the framework does confer protection for adolescent boys while enabling access to male circumcision; however, we identify ambiguities and tensions that exist between the Children’s Act, regulations and national guidelines. We recommend reform to further enable access by this vulnerable group to this prevention modality

Introducing the concept of Potential Aerosol Mass (PAM)

International audiencePotential Aerosol Mass (PAM) can be defined as the maximum aerosol mass that the oxidation of precursor gases produces. In the measurement, all precursor gases are rapidly oxidized with extreme amounts of oxidants to low volatility compounds, resulting in the aerosol formation. Oxidation occurs in a small, simple, flow-through chamber that has a short residence time and is irradiated with ultraviolet light. The amount of the oxidants ozone (O3), hydroxyl (OH), and hydroperoxyl (HO2) were measured directly and can be controlled by varying the UV light and the relative humidity. Maximum values were 40 ppmv for O3 500 pptv for OH, and 4 ppbv for HO2. The oxidant amounts are 100 to 1000 times troposphere values, but the ratios OH/O3 and HO2/OH are similar to troposphere values. The aerosol production mechanism and the aerosol mass yield were studied for several controlling variables, such as temperature, relative humidity, oxidant concentration, presence of nitrogen oxides (NOx), precursor gas composition and amount, and the presence of acidic seed aerosol. The measured secondary organic aerosol (SOA) yield of several natural and anthropogenic volatile organic compounds and a mixture of hydrocarbons in the PAM chamber were similar to those obtained in large, batch-style environmental chambers. This PAM method is being developed for measuring potential aerosol mass in the atmosphere, but is also useful for examining SOA processes in the laboratory and in environmental chambers

The Role of Small to Moderate Volcanic Eruptions in the Early 19th Century Climate

Small-to-moderate volcanic eruptions can lead to significant surface cooling when they occur clustered, as observed in recent decades. In this study, based on new high-resolution ice-core data from Greenland, we produce a new volcanic forcing data set that includes several small-to-moderate eruptions not included in prior reconstructions and investigate their climate impacts of the early 19th century through ensemble simulations with the Max Planck Institute Earth System Model. We find that clustered small-to-moderate eruptions produce significant additional global surface cooling (∼0.07 K) during the period 1812–1820, superposing with the cooling by large eruptions in 1809 (unidentified location) and 1815 (Tambora). This additional cooling helps explain the reconstructed long-lasting cooling after the large eruptions, but simulated regional impacts cannot be confirmed with reconstructions due to a low signal-to-noise ratio. This study highlights the importance of small-to-moderate eruptions for climate simulations as their impacts can be comparable with that of solar irradiance changes

Emissions from biomass burning in the Yucatan

In March 2006 two instrumented aircraft made the first detailed field measurements of biomass burning (BB) emissions in the Northern Hemisphere tropics as part of the MILAGRO project. The aircraft were the National Center for Atmospheric Research C-130 and a University of Montana/US Forest Service Twin Otter. The initial emissions of up to 49 trace gas or particle species were measured from 20 deforestation and crop residue fires on the Yucatan peninsula. This included two trace gases useful as indicators of BB (HCN and acetonitrile) and several rarely, or never before, measured species: OH, peroxyacetic acid, propanoic acid, hydrogen peroxide, methane sulfonic acid, and sulfuric acid. Crop residue fires emitted more organic acids and ammonia than deforestation fires, but the emissions from the main fire types were otherwise fairly similar. The Yucatan fires emitted unusually high amounts of SO2 and particle chloride, likely due to a strong marine influence on this peninsula. As smoke from one fire aged, the ratio ΔO3/ΔCO increased to ~15% in 1×10^7 molecules/cm^3) that were likely caused in part by high initial HONO (~10% of NO_y). Thus, more research is needed to understand critical post emission processes for the second-largest trace gas source on Earth. It is estimated that ~44 Tg of biomass burned in the Yucatan in the spring of 2006. Mexican BB (including Yucatan BB) and urban emissions from the Mexico City area can both influence the March-May air quality in much of Mexico and the US

Ozone loss derived from balloon-borne tracer measurements in the 1999/2000 Arctic winter

Balloon-borne measurements of CFC11 (from the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 Arctic winter as part of the SOLVE-THESEO 2000 campaign, based in Kiruna (Sweden). Here we present the CFC11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC11 and O3 measured on the flights. The peak ozone loss (~1200ppbv) occurs in the 440-470K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days

Isoprene oxidation products are a significant atmospheric aerosol component

International audienceGlycolaldehyde, hydroxyacetone, and methylglyoxal, which are known isoprene oxidation products, were collected during two field experiments using an annular denuder sampling system and compared to a model calculation. The compounds in gas and aerosol phases were determined during both experiments. Global variation and distribution of the aerosol mass contribution of the compounds were predicted using the measurements, the box model results, and gas-phase concentrations and humidity simulated by a global 3-D model. Here we report the estimates of a global annual contribution of 35 (10?120) Tg of aerosol organic matter from isoprene

Addressing legal and policy barriers to male circumcision for adolescent boys in South Africa

With millions of adolescents becoming infected with HIV globally, it is essential that barriers to much-needed interventions are reduced for at-risk adolescents. In this article we review the legal and policy framework in South Africa for adolescent access to male circumcision. We are of the view that the framework does confer protection for adolescent boys while enabling access to male circumcision; however, we identify ambiguities and tensions that exist between the Children’s Act, regulations and national guidelines. We recommend reform to further enable access by this vulnerable group to this prevention modality

Introducing the concept of Potential Aerosol Mass (PAM)

La Constitución Política de Colombia de 1991 intentó consolidar un proceso de cambio cultural tendiente a modernizar la administración pública haciendo más eficaces, eficientes y económicos los procedimientos de gobierno y por consiguiente, el desempeño de los empleados oficiales

Sequence organization and molecular cloning of mouse mammary tumor virus DNA endogenous to C57BL/6 mice.

The sequence organization of mouse mammary tumor virus DNA endogenous to the C57BL/6 inbred mouse strain was characterized by Southern blot analysis, utilizing probes specific for particular regions of the mouse mammary tumor virus provirus and by molecular cloning of endogenous mouse mammary tumor virus DNA. The genome of C57BL/6 mice contains three apparently intact, endogenous proviral units; two of these units comprise the Mtv-8 (unit II) and Mtv-9 (unit III) genetic loci that are also present in the DNA of BALB/c mice. The third unit is defined by EcoRI restriction fragments of 10.0 and 8.4 kilobases that contain the 5' and 3' portions of the provirus, respectively. This unit, termed unit XI and encoded by the genetic locus Mtv-17, has not been previously recognized in C57BL/6 DNA, but it can be clearly distinguished from the proviral units at Mtv-8 and Mtv-9 by Southern blot analysis under appropriate conditions. The proviral unit at Mtv-17 is not present in BALB/c DNA. DNAs comprising the entire Mtv-8 locus and the 3' portions of Mtv-9 and Mtv-17 were cloned. Analysis of the cloned DNA revealed no obvious deletions or rearrangements that would render proviral DNA defective; however, these endogenous genes are normally not transcriptionally active

Ozone loss derived from balloon-borne tracer measurements and the SLIMCAT CTM

Balloon-borne measurements of CFC-11 (on flights of the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 winter as part of the SOLVE-THESEO 2000 campaign. Here we present the CFC-11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3-D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC-11 and O3 measured on the flights, the peak ozone loss (1200 ppbv) occurs in the 440–470 K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three independent balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days