Results of a Community Mentoring Programme for Youth Heads of Household in Rwanda: Effects on Youth Sexual Risk Behaviours and Maltreatment

Background: While mentorship programmes, which connect orphans with adults to whom they can turn to for help and advice, are proliferating in an attempt to prevent high-risk behaviours in adolescents, there are few data to show that mentorship actually makes a difference among youth heads of households (YHH). The purpose of this study was to: (a) investigate the impact of mentoring relationship on sexual risk behaviours outcomes among YHH, and (b) examine the impact of the mentoring programme on youth maltreatment including sexual abuse. Methods: The research used a quasi-experimental design to assess the impact of the adult mentoring programme on sexual risk behaviours and maltreatment of youth living without adult care in four districts of the then Gikongoro province. In the design, which includes a baseline and a follow-up survey, the intervention group (Maraba and Nyamagabe districts) with youth heads of households receiving the home visitation programme were compared to a comparisongroup (Mudasomwa and Nyaruguru districts). Analyses explored linkages between exposure to the intervention and various outcomes: HIV/AIDS knowledge, perception of HIV risk infection, sexual risk behaviours, and maltreatment. Logistic regression was used to examine whether the mentoring programme predicted outcomes of maltreatment or sexual behaviours when controlling for demographic characteristics and any other variables significant at the bivariate level. Results: The overall HIV/AIDS knowledge was higher in the intervention group (16.3% versus 12.5%) and more YHH in this group knew a place where to get a condom (64.5% versus 57.8%). In this group, youth were more likely to report use of condom (20.5 versus 12.4%), to perceive a risk of HIV/AIDS infection at the follow-up survey (44.7% versus 32.8%), and less consumption of alcohol (56.3 versus 41.7%). In the logistic regression, respondents who reported more adult support had a significantly high likelihood of being sexually inexperienced (OR = 1.20, score for adult support=3.67 versus 3.53, p=.05). During the last twelve months, being in school, male gender, and less marginalization were highly associated with being abstinent (AOR=4.68, 2.72, and 1.46, respectively). The level of maltreatment has sensibly diminished in the intervention group (from 1.53 to 1.27) during the last two years. There were more youth who reported physical abuse among the comparison group (24% versus 15.9%) and labour exploitation (29.5% versus 19.6%). YHH exposed to the intervention were less likely to suffer from labour exploitation and physical abuse (AOR = .52 and .63, respectively). Conclusions: Results indicate that the utilization of community adult mentors should be supported as a key strategy in working with YHH to decrease sexual risk behaviours and maltreatment from community members. For interventions to be optimally effective, specific strategies to promote community support and decrease marginalization need to be identified.Key words: Youth heads of household, mentoring, sexual risk behaviours, maltreatment, abuse, Rwand

Maltreatment of Youth Heads of Households in Rwanda

BackgroundIn Rwanda, the combined effects of the 1994 genocide and the spread of AIDS have resulted in large numbers of orphans. Many of these are not only orphans but also youth heads of households (YHH). Orphans and YHH are particularly vulnerable to maltreatment because of marginalization from the community. The objectives of this study were to: (a) determine the prevalence of maltreatment among YHH after a two year follow-up by age and gender; (b) assess the association between certain behavioral, contextual, and socio-demographic factors and maltreatment; and (c) determine predictors of maltreatment in that community.MethodsCross-sectional survey of 692 YHH, aged 10-24, in Gikongoro, Rwanda, all beneficiaries of a World Vision basic needs program. In addition, four gender-mixed focus groups with youth with a total of 32 participants and nine gender-mixed focus groups with adults from the community with a total 61 participants were held.ResultsThe findings reveal that the prevalence of maltreatment is very high, with 71.5% of YHH self-reporting at least one type of abuse and 88% reporting having land or possessions taken or damaged. Focus group discussions identified four primary factors representing a source for violence and exploitation of YHH and results from the regression analysis showed that factors indicating community connectedness and children’s externalizing behaviors were the most salient predictors of positive treatment or maltreatment of YHH. Additionally, because of the support they had received from World Vision Program, the YHH are perceived as “better-off” or “rich” by some members of the community and this jealousy contributes in the mistreatment of orphans. Survey results are consistent with this assertion as almost 78 % of YHH reported that people were jealous of the services they were receiving.ConclusionThese findings provide new information on the issues surrounding the maltreatment of orphans in a poor, rural setting in Rwanda. Although the results should be regarded as primarily exploratory suggestive for further studies, they call for urgent need to address such a serious problem. The findings also suggest the importance of considering any new programs for orphans and YHH in the context of the wider community so as not to inadvertently add to their problems by creating resentment in the surrounding community

Impact of facial conformation on canine health: Brachycephalic Obstructive Airway Syndrome

The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring

Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond

The nitrogen-vacancy (N-V) center in diamond is a promising atomic-scale system for solid-state quantum information processing. Its spin-dependent photoluminescence has enabled sensitive measurements on single N-V centers, such as: electron spin resonance, Rabi oscillations, single-shot spin readout and two-qubit operations with a nearby 13C nuclear spin. Furthermore, room temperature spin coherence times as long as 58 microseconds have been reported for N-V center ensembles. Here, we have developed an angle-resolved magneto-photoluminescence microscopy apparatus to investigate the anisotropic electron spin interactions of single N-V centers at room temperature. We observe negative peaks in the photoluminescence as a function of both magnetic field magnitude and angle that are explained by coherent spin precession and anisotropic relaxation at spin level anti-crossings. In addition, precise field alignment unmasks the resonant coupling to neighboring dark nitrogen spins that are not otherwise detected by photoluminescence. The latter results demonstrate a means of investigating small numbers of dark spins via a single bright spin under ambient conditions.Comment: 13 pages, 4 figure

The stellar halo of the Galaxy

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd

Genomic and protein structural maps of adaptive evolution of human influenza a virus to increased virulence in the mouse

Adaptive evolution is characterized by positive and parallel, or repeated selection of mutations. Mouse adaptation of influenza A virus (IAV) produces virulent mutants that demonstrate positive and parallel evolution of mutations in the hemagglutinin (HA) receptor and non-structural protein 1 (NS1) interferon antagonist genes. We now present a genomic analysis of all 11 genes of 39 mouse adapted IAV variants from 10 replicate adaptation experiments. Mutations were mapped on the primary and structural maps of each protein and specific mutations were validated with respect to virulence, replication, and RNA polymerase activity. Mouse adapted (MA) variants obtained after 12 or 20-21 serial infections acquired on average 5.8 and 7.9 nonsynonymous mutations per genome of 11 genes, respectively. Among a total of 115 nonsynonymous mutations, 51 demonstrated properties of natural selection including 27 parallel mutations. The greatest degree of parallel evolution occurred in the HA receptor and ribonucleocapsid components, polymerase subunits (PB1, PB2, PA) and NP. Mutations occurred in host nuclear trafficking factor binding sites as well as sites of virus-virus protein subunit interaction for NP, NS1, HA and NA proteins. Adaptive regions included cap binding and endonuclease domains in the PB2 and PA polymerase subunits. Four mutations in NS1 resulted in loss of binding to the host cleavage and polyadenylation specificity factor (CPSF30) suggesting that a reduction in inhibition of host gene expression was being selected. The most prevalent mutations in PB2 and NP were shown to increase virulence but differed in their ability to enhance replication and demonstrated epistatic effects. Several positively selected RNA polymerase mutations demonstrated increased virulence associated with >300% enhanced polymerase activity. Adaptive mutations that control host range and virulence were identified by their repeated selection to comprise a defined model for studying IAV evolution to increased virulence in the mouse

A search for the decay modes B+/- to h+/- tau l

We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.

Evidence for an excess of B -> D(*) Tau Nu decays

Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg

X-Ray Spectroscopy of Stars

(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense, of X-ray spectra from the solar corona. X-ray emission from cool stars is indeed ascribed to magnetically trapped hot gas analogous to the solar coronal plasma. Coronal structure, its thermal stratification and geometric extent can be interpreted based on various spectral diagnostics. New features have been identified in pre-main sequence stars; some of these may be related to accretion shocks on the stellar surface, fluorescence on circumstellar disks due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot stars clearly dominate the interaction with the galactic interstellar medium: they are the main sources of ionizing radiation, mechanical energy and chemical enrichment in galaxies. High-energy emission permits to probe some of the most important processes at work in these stars, and put constraints on their most peculiar feature: the stellar wind. Here, we review recent advances in our understanding of cool and hot stars through the study of X-ray spectra, in particular high-resolution spectra now available from XMM-Newton and Chandra. We address issues related to coronal structure, flares, the composition of coronal plasma, X-ray production in accretion streams and outflows, X-rays from single OB-type stars, massive binaries, magnetic hot objects and evolved WR stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures (partly multiple); some corrections made after proof stag

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal