Orphans of the AIDS epidemic? The extent, nature and circumstances of child-headed households in South Africa

There is widespread concern that the number of children living in “child-headed households” is rapidly increasing as a result of AIDS-related adult mortality in much of sub-Saharan Africa. Based on analyses of data from several representative national surveys over the period 2000–2007, this paper examines the extent to which this is the case in South Africa. It explores trends in the number of children living in child-only households and characterises these children relative to children living in households with adults (mixed-generation households). The findings indicate that the proportion of child-only households is relatively small (0.47% in 2006) and does not appear to be increasing. In addition, the vast majority (92.1%) of children resident in child-only households have a living parent. The findings raise critical questions about the circumstances leading to the formation of child-only households and highlight that they cannot for the main part be ascribed to HIV orphaning. Nonetheless, the number of children living in this household form is not insignificant, and their circumstances, when compared with children in mixed-generation households, indicate a range of challenges, including greater economic vulnerability and inadequate service access. We argue that a solitary focus on the HIV epidemic and its related orphaning as the cause of child-only households masks other important issues for consideration in addressing their needs, and risks the development of inappropriate policies, programmes and interventions

Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function

Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of l

Burning rate of liquid fuel on carpet (porous media)

The occurrence of a liquid fuel burning on carpet has been involved in many incendiary and accidental fires. While the research on a liquid fuel fire on carpet is still limited, much work on porous media has been performed using sand or glass beads soaked with liquid fuel. In this study, a heat and mass transfer theory was first developed to analyze the burning process of liquid on carpet, and then several small-scale tests were performed to validate the theory. This analysis is valid for pool fires intermediate in size (5-20 cm. in diameter). The experimental apparatus consisted of a circular pan (105 mm) and a load cell. Varying amounts of fuels (heptane, kerosene and methanol) were spilled onto the carpet, which was allowed to burn in a quiescent environment. It was found that due to the different controlling mechanisms, the liquid burning rate could be less or more than that of a similarly spilled free-burning pool fire. For the worst-case scenario in fires, the maximum enhancement of the burning rate due to the porous media is predictable through the physical properties of the fuel. This analysis is valid for both combustion and evaporation. Several similar results in the scientific literature are analyzed to further describe the trend. This work explains the role of carpet in liquid pool fires and also helps to explain special risks related to the presence of carpet involved in arsons and will be useful in reconstruction of the early development of an incendiary or accidental fire

Sucrose cycling in heterotrophic plant cell metabolism: first step towards an experimental model

International audienc

Lipoxygenase-mediated production of fatty acid hydroperoxides is a specific signature of the hypersensitive reaction in plants

International audienc

Non-specific disease resistance upon pathogen-induced expression of a fungal elicitor in tobacco

National audienc

Compound-mediated assay interferences in homogenous proximity assays.

Homogeneous proximity assays are widely implemented in high-throughput screening (HTS) of small-molecule libraries for drug and probe discovery. Representative technologies include amplified luminescent proximity homogeneous assays (ALPHA, which is trademarked by PerkinElmer; also informally referred to as Alpha), Förster/fluorescence resonance energy transfer (FRET), time-resolved FRET (TR-FRET) and homogeneous time-resolved fluorescence (HTRF, which is trademarked by CisBio), bioluminescence resonance energy transfer (BRET), and scintillation proximity assays (SPA). While highly useful, these assay technologies are susceptible to a variety of technology-related compound-mediated interferences, most notably signal attenuation (e.g., through quenching, inner-filter effects, light scattering), signal emission (e.g., auto-fluorescence), and disruption of affinity capture components such as affinity tags and antibodies. These assays are also susceptible to more generalized compound-mediated interferences such as nonspecific reactivity and aggregation. This chapter describes (a) the basic principles of proximity assays, (b) common sources of compound-mediated assay interference in homogenous proximity assays, and (c) counter-screens and other strategies to classify compound-mediated assay interferences in homogenous proximity assays. This information should be useful for prioritizing bioactive compounds in homogenous proximity assays for drug and chemical probe discovery

Assimilation of Global Satellite Leaf Area Estimates Reduces Modeled Global Carbon Uptake and Energy Loss by Terrestrial Ecosystems

Carbon, water and energy exchange between the land and atmosphere controls how ecosystems either accelerate or ameliorate the effect of climate change. However, evaluating improvements to processes controlling carbon cycling, water use and energy exchange in global land surface models (LSMs) remains challenging in part because of persistent model errors in estimating leaf area. Here we evaluate the changes in global carbon, water and energy exchange brought about when a LSM prognostic estimates of leaf area are made consistent with estimates from satellites. This approach achieves two aims; first to quantify the effect of ignoring errors in leaf area index (LAI) on land-atmosphere fluxes and second, to evaluate how closely this LSM replicates fluxes with and without an LAI constraint. We implemented an ensemble Kalman filter with spatiotemporal adaptive inflation to more closely match community land model (CLM5.0) estimates of leaf area to those from the Global Inventory Modeling and Mapping Studies leaf area index (LAI3g) product. We then evaluate the model's estimates of gross primary productivity (GPP) and latent heat flux (LE) against well established global estimates of these fluxes. We find that the model is biased high by 27% relative to the LAI3g product. Moreover, the effect of bias in LAI is substantial for GPP (18%) and LE (6%) and likely to confound efforts to refine processes controlling these fluxes. This data assimilation approach serves as a method to evaluate the efficacy of refinements to flux processes until the processes controlling the dynamics of LAI are better resolved in LSMs. © 2022. American Geophysical Union. All Rights Reserved.6 month embargo; first published: 15 July 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Protection de plantes par "immunisation génétique" : obtention et caractérisation de tabacs transgéniques exprimant un gène d'élicitine sous contrôle d'un promoteur inductible

National audienc