165 research outputs found

    Women's Perceptions and Misperceptions of Male Circumcision: A Mixed Methods Study in Zambia.

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    Women's perceptions of male circumcision (MC) have implications for behavioral risk compensation, demand, and the impact of MC programs on women's health. This mixed methods study combines data from the first two rounds of a longitudinal study (n = 934) and in-depth interviews with a subsample of respondents (n = 45) between rounds. Most women correctly reported that MC reduces men's risk of HIV (64% R1, 82% R2). However, 30% of women at R1, and significantly more (41%) at R2, incorrectly believed MC is fully protective for men against HIV. Women also greatly overestimated the protection MC offers against STIs. The proportion of women who believed MC reduces a woman's HIV risk if she has sex with a man who is circumcised increased significantly (50% to 70%). Qualitative data elaborate women's misperception regarding MC. Programs should address women's informational needs and continue to emphasize that condoms remain critical, regardless of male partner's circumcision status

    The merchants of meta: A research agenda to understand the future of retailing in the metaverse

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    Due to rapid technological developments, the metaverse is quickly garnering attention from all areas of retailing. With a projected market of $800 billion by 2024, the metaverse is expected to radically reshape retailing in the digital world. However, very little is known about the metaverse from a customer, retailer, or brand perspective. This article summarizes how the metaverse has been conceptualized thus far in the literature and the popular press. The authors offer a new conceptualization of the metaverse that contains four distinct dimensions: online collaboration, high consumer immersion, unique digital assets, and digital personas. Considering that the technologies currently used to provide high consumer immersion (e.g., augmented reality, virtual reality) and unique digital assets (e.g., blockchain technology) are not fully developed or commercialized, the authors also propose the concept of a transitory metaverse to understand the current stage of metaverse development better. The authors conclude by providing 27 directions for future research based on a full factorial of how the metaverse dimensions amplify three customer touchpoints in the digital experience (digital economic exchange, complex social relationships, direct environment interaction) for the three main stakeholders of any retailing exchange (consumers, retailers, brands) along the entire customer journey (pre-purchase, purchase, post-purchase)

    Skill retention after school-leaving: Analysis of data from the Malawi Schooling and Adolescent Study

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    The skills young people develop in school provide an essential foundation that can either be reinforced or deteriorate depending on the strength of the foundation and opportunities after leaving school. This brief describes findings from an analysis of a longitudinal data set of Malawian adolescents aged 14–17 attending school when first interviewed in 2007. The study investigated whether literacy and numeracy skills at school-leaving—among those who dropped out before completing secondary school—were retained several years after. Results show a significant gender difference in skill level after school-leaving for English skills, even after controlling for initial skill level and grade attainment, with females scoring lower than males. Although the gender difference in numeracy is not significant, females score lower than males after school-leaving. These findings have important implications for education policy and programs

    Adolescent Girls Empowerment Programme: Research and evaluation baseline technical report

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    The theory of change behind the Adolescent Girls Empowerment Program (AGEP) posits that adolescent girls are empowered by acquiring social, health, and economic assets. Girls can draw on these assets to reduce vulnerabilities and expand opportunities, thereby increasing their likelihood of completing school, delaying sexual debut, and reducing the risk of early marriage, unintended pregnancy, acquisition of HIV, and so on. AGEP serves vulnerable adolescent girls in Zambia aged 10–19 in two age cohorts: 10–14-year-olds and 15–19-year-olds. AGEP operates in ten “master sites,” five urban and five rural, in four provinces of Zambia. The three core components of AGEP in Zambia are: safe spaces, savings accounts, and health vouchers. The primary aim of the research outlined in this baseline technical report is to obtain as rigorous an assessment as possible of the impact of AGEP on mediating, and on longer-term demographic, reproductive, and health outcomes among vulnerable adolescent girls as they age from 10–19 in 2013 to 14–23 in 2017

    CIV Emission and the Ultraviolet through X-ray Spectral Energy Distribution of Radio-Quiet Quasars

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    In the restframe UV, two of the parameters that best characterize the range of emission-line properties in quasar broad emission-line regions are the equivalent width and the blueshift of the CIV line relative to the quasar rest frame. We explore the connection between these emission-line properties and the UV through X-ray spectral energy distribution (SED) for radio-quiet (RQ) quasars. Our sample consists of a heterogeneous compilation of 406 quasars from the Sloan Digital Sky Survey and Palomar-Green survey that have well-measured CIV emission-line and X-ray properties (including 164 objects with measured Gamma). We find that RQ quasars with both strong CIV emission and small CIV blueshifts can be classified as "hard-spectrum" sources that are (relatively) strong in the X-ray as compared to the UV. On the other hand, RQ quasars with both weak CIV emission and large CIV blueshifts are instead "soft-spectrum" sources that are (relatively) weak in the X-ray as compared to the UV. This work helps to further bridge optical/soft X-ray "Eigenvector 1" relationships to the UV and hard X-ray. Based on these findings, we argue that future work should consider systematic errors in bolometric corrections (and thus accretion rates) that are derived from a single mean SED. Detailed analysis of the CIV emission line may allow for SED-dependent corrections to these quantities.Comment: AJ, in press; 39 pages, 11 figures, 3 table

    Effects of supersymmetric grand unification scale physics on Γ(bsγ)\Gamma \left( b\to s\gamma\right)

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    Although calculations of the bsγb\rightarrow s\gamma rate in supersymmetric grand unified models have always either ignored the gluino mediated contribution or found it to be negligible, we show that taking universal supersymmetry breaking masses at the Planck scale, rather than at the gauge unification scale as is customary, leads to the gluino contribution being more significant and in fact sometimes even larger than the chargino mediated contributions when μ>0\mu >0 and tanβ\tan{\beta} is of order 1. The impact is greatest felt when the gluinos are relatively light. Taking the universal boundary condition at the Planck scale also has an effect on the chargino contribution by increasing the effect of the wino and higgsino-wino mediated decays. The neutralino mediated contribution is found to be enhanced, but nevertheless it remains relatively insignificant.Comment: Title changed, final version as accepted for PRD, 12 pages, 6 Figures (Figs.2-6 included, uuencoded, epsf.tex

    Mass Functions of the Active Black Holes in Distant Quasars from the Large Bright Quasar Survey, the Bright Quasar Survey, and the Color-Selected Sample of the SDSS Fall Equatorial Stripe

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    We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey, the Bright Quasar Survey, and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts (0 <~ z <= 5) and were subject to different selection criteria and flux density limits. These samples are thus complementary and can help us gain additional insight on the true underlying black hole mass distribution, free from selection effects and mass estimation errors through future studies. We see evidence that the active z~4 black hole population is somewhat different than that at lower z. In particular, there is a sharp increase in the space density of the detected active black holes (M_BH >~ 10^8 Msun) between redshifts ~4 and ~2.5. Also, the z~4 SDSS quasar mass function has a somewhat flatter high mass-end slope, beta = -1.75 +- 0.56, compared to the mass functions based on quasars below z of 3, which display typical slopes of beta =~ -3.3; the latter are consistent with the mass functions at similar redshifts based on the SDSS Data Release 3 quasar catalog presented by Vestergaard et al. We see clear evidence of cosmic downsizing in the comoving space density distribution of active black holes in the LBQS sample alone. In forthcoming papers, further analysis, comparison, and discussion of these mass functions will be made with other existing black hole mass functions, notably that based on the SDSS DR3 quasar catalog. We present the relationships used to estimate the black hole mass based on the MgII emission line; the relations are calibrated to the Hbeta and CIV relations by means of several thousand high quality SDSS spectra. Mass estimates of the individual black holes of these samples are also presented.Comment: Accepted for publication in Astrophysical Journal. 22 pages, including 11 figures and 11 table

    Optical identification of XMM sources in the CFHTLS

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    We present optical spectroscopic identifications of X-ray sources in ~3 square degrees of the XMM-Large Scale Structure survey (XMM-LSS), also covered by the Canada France Hawaii Telescope Legacy Survey (CFHTLS), obtained with the AAOmega instrument at the Anglo Australian Telescope. In a flux limited sample of 829 point like sources in the optical band with g' <~22 mag and the 0.5-2 keV flux > 1x10^{-15}erg/cm^2/s, we observed 695 objects and obtained reliable spectroscopic identification for 489 sources, ~59% of the overall sample. We therefore increase the number of identifications in this field by a factor close to five. Galactic stellar sources represent about 15% of the total (74/489). About 55% (267/489) are broad-line Active Galactic Nuclei (AGNs) spanning redshifts between 0.15 and 3.87 with a median value of 1.68. The optical-to-X-ray spectral index of the broad-line AGNs is 1.47, typical of optically-selected Type I quasars and is found to correlate with the rest frame X-ray and optical monochromatic luminosities at 2 keV and 2500 angstroms respectively. Consistent with previous studies, we find alpha_ox not to be correlated with z. In addition, 32 and 116 X-ray sources are, respectively absorption and emission-line galaxies at z<0.76. From a line ratio diagnostic diagram it is found that in about 50% of these emission line galaxies, the emission lines are powered significantly by the AGN. Thirty of the XMM sources are detected at one or more radio frequencies. In addition, 24 sources have ambiguous identification: in 8 cases, two XMM sources have a single optical source within 6 arcsecs of each of them, whereas, 2 and 14 XMM sources have, respectively, 3 and 2 possible optical sources within 6 arcsecs of each of them.Comment: 15 pages, 14 figures, 5 tables, accepted for publication in MNRA

    Type 1 low z AGN. I. Emission properties

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    We analyze the emission properties of a new sample of 3,579 type 1 AGN, selected from the SDSS DR7 based on the detection of broad H-alpha emission. The sample extends over a broad H-alpha luminosity L_bHa of 10^40 - 10^44 erg s^-1 and a broad H-alpha FWHM of 1,000 - 25,000 km s^-1, which covers the range of black hole mass 10^6<M_BH/M_Sun<10^9.5 and luminosity in Eddington units 10^-3 < L/L_Edd < 1. We combine ROSAT, GALEX and 2MASS observations to form the SED from 2.2 mic to 2 keV. We find the following: 1. The distribution of the H-alpha FWHM values is independent of luminosity. 2. The observed mean optical-UV SED is well matched by a fixed shape SED of luminous quasars, which scales linearly with L_bHa, and a host galaxy contribution. 3. The host galaxy r-band (fibre) luminosity function follows well the luminosity function of inactive non-emission line galaxies (NEG), consistent with a fixed fraction of ~3% of NEG hosting an AGN, regardless of the host luminosity. 4. The hosts of lower luminosity AGN have a mean z band luminosity and u-z colour which are identical to NEG with the same redshift distribution. With increasing L_bHa the AGN hosts become bluer and less luminous than NEG. The implied increasing star formation rate with L_bHa is consistent with the relation for SDSS type 2 AGN of similar bolometric luminosity. 5. The optical-UV SED of the more luminous AGN shows a small dispersion, consistent with dust reddening of a blue SED, as expected for thermal thin accretion disc emission. 6. There is a rather tight relation of nuL_nu(2 keV) and L_bHa, which provides a useful probe for unobscured (true) type 2 AGN. 7. The primary parameter which drives the X-ray to UV emission ratio is the luminosity, rather than M_BH or L/L_Edd.Comment: 33 pages, 23 figures; accepted for publication in MNRAS; complete versions of tables 1 and B1 can be found at http://physics.technion.ac.il/~stern/PaperData/Type1AGN1
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