Limits on Active-Sterile Neutrino Mixing and the Primordial Deuterium Abundance

Studies of limits on active-sterile neutrino mixing derived from big bang nucleosynthesis considerations are extended to consider the dependance of these constraints on the primordial deuterium abundance. This study is motivated by recent measurements of D/H in quasar absorption systems, which at present yield discordant results. Limits on active-sterile mixing are somewhat relaxed for high D/H. For low D/H ($\approx 2 \times 10^{-5}$), no active-sterile neutrino mixing is allowed by currently popular upper limits on the primordial $^4$He abundance $Y$. For such low primordial D/H values, the observational inference of active-sterile neutrino mixing by upcoming solar neutrino experiments would imply that $Y$ has been systematically underestimated, unless there is new physics not included in standard BBN.Comment: 10 pages + 2 figures, uses revtex macros, submitted to Phys. Rev. D. Corrected figure captions and an added referenc

HIV self-testing among young women in rural South Africa: A randomized controlled trial comparing clinic-based HIV testing to the choice of either clinic testing or HIV self-testing with secondary distribution to peers and partners

Background: HIV testing rates in many hyper-endemic areas are lower than needed to curtail the HIV epidemic. New HIV testing strategies are needed to overcome barriers to traditional clinic based testing; HIV self-testing is one modality that offers promise in reaching individuals who experience barriers to clinic-based testing. Methods: We conducted a randomized control trial among young women ages 18-26 living in rural Mpumalanga, South Africa where they were randomized in a 1:1 allocation to either the: (1) HIV Counseling and Testing (HCT) arm: an invitation to test at one of the 9 local government clinics where free HCT is provided and is standard of care (SOC), or (2) choice arm: choice of either a clinic-based HCT invitation or oral HIV Self-Testing (HIVST) kits. Depending on the arm, participants were also provided either: (1) 4 HCT invitations to provide to peers/partners for HIV testing at one of the 9 local clinics, or (2) 4 HIV self-test kits to provide to peers/partners (thus 5 total HIVST kits or HCT invitations). Young women were asked to return 3 months and 9 months after enrollment to assess testing uptake and invitation or kit distribution to peers and partners and experiences with testing. Peers and partners who were reported by index participants to have received kits/invitations during follow-up visits were also invited to attend a study visit to assess their testing experiences. The trial is registered at clinical trials.gov NCT03162965. Findings: 287 young women were enrolled and randomized, with 146 randomized to the HCT arm and 141 to the choice (HCT or HIVST) arm. Of those randomized to the choice arm, over 95% (n=135) chose the HIV self-testing kit and only 6 individuals chose HCT. At the 3-month follow-up visit, 92% of index participants in the choice arm reported having tested for HIV compared to 43% of participants in the HCT arm, resulting in a significant risk difference of 49% (95% CI 40%, 58%). By 9 months, this difference decreased to a risk difference of 25% (95% CI 17%, 33%) between arms (96% in the choice arm and 72% in the HCT arm). Participants in the choice arm were also more likely to invite peers and partners to test compared to the HCT arm (94% vs. 76% or an average of 4.97 vs 2.79 tests). Few male partners were invited to test by index participants; however, index participants in the choice arm were more likely to have their male partners test than index participants in the HCT arm (RR 2.99, 95% CI 1.45, 6.16). Interpretation: When given a choice between clinic-based HIV testing and HIV oral self-testing, the overwhelming majority of young women chose HIVST. In addition, those offered a choice of HIV testing modality were much more likely to test, distribute test kits to peers and partners, and to have peers and partners who reported testing compared to the HCT arm. Self-testing offers an important opportunity to significantly increase testing rates among young women and their peers and partners compared to clinic-based HCT. Other strategies to reach men with testing are needed. Funding: US National Institutes of Healt

Imprint of Sterile Neutrinos in the Cosmic Microwave Background Radiation

The existence of low-mass sterile neutrinos is suggested by the current status of solar and atmospheric neutrinos together with the LSND experiment. In typical four-flavor scenarios, neutrinos would contribute to a cosmic hot dark matter component and to an increased radiation content at the epoch of matter-radiation equality. These effects leave their imprint in sky maps of the cosmic microwave background radiation (CMBR) and may thus be detectable with the precision measurements of the upcoming MAP and PLANCK missions.Comment: 5 pages, 2 postscript figures, matches version to appear in PR

Data resource profile: network for analysing longitudinal population-based HIV/AIDS data on Africa (ALPHA Network)

The Network for Analysing Longitudinal Population-based HIV/AIDS data on Africa (ALPHA Network, http://alpha.lshtm.ac.uk/) brings together ten population-based HIV surveillance sites in eastern and southern Africa, and is coordinated by the London School of Hygiene and Tropical Medicine (LSHTM). It was established in 2005 and aims to (i) broaden the evidence base on HIV epidemiology for informing policy, (ii) strengthen the analytical capacity for HIV research, and (iii) foster collaboration between network members. All study sites, some starting in the late 1980s and early 1990s, conduct demographic surveillance in populations that range from approximately 20 to 220 thousand individuals. In addition, they conduct population-based surveys with HIV testing, and verbal autopsy interviews with relatives of deceased residents. ALPHA Network datasets have been used for studying HIV incidence, sexual behaviour and the effects of HIV on mortality, fertility, and household composition. One of the network’s substantive focus areas is the monitoring of AIDS mortality and HIV services coverage in the era of antiretroviral therapy. Service use data are retrospectively recorded in interviews and supplemented by information from record linkage with medical facilities in the surveillance areas. Data access is at the discretion of each of the participating sites, but can be coordinated by the network

Imported malaria in a cosmopolitan European city: A mirror image of the world epidemiological situation

© 2008 Millet et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Full Factorial Analysis of Mammalian and Avian Influenza Polymerase Subunits Suggests a Role of an Efficient Polymerase for Virus Adaptation

Amongst all the internal gene segments (PB2. PB1, PA, NP, M and NS), the avian PB1 segment is the only one which was reassorted into the human H2N2 and H3N2 pandemic strains. This suggests that the reassortment of polymerase subunit genes between mammalian and avian influenza viruses might play roles for interspecies transmission. To test this hypothesis, we tested the compatibility between PB2, PB1, PA and NP derived from a H5N1 virus and a mammalian H1N1 virus. All 16 possible combinations of avian-mammalian chimeric viral ribonucleoproteins (vRNPs) were characterized. We showed that recombinant vRNPs with a mammalian PB2 and an avian PB1 had the strongest polymerase activities in human cells at all studied temperature. In addition, viruses with this specific PB2-PB1 combination could grow efficiently in cell cultures, especially at a high incubation temperature. These viruses were potent inducers of proinflammatory cytokines and chemokines in primary human macrophages and pneumocytes. Viruses with this specific PB2-PB1 combination were also found to be more capable to generate adaptive mutations under a new selection pressure. These results suggested that the viral polymerase activity might be relevant for the genesis of influenza viruses of human health concern

Three Neutrino Δm2\Delta m^2 scales and Singular Seesaw Mechanism

It is shown that the singular seesaw mechanism can simultaneously explain all the existing data supporting nonzero neutrino masses and mixing. The three mass-squared differences that are needed to accommodate the atmospheric neutrino data (through $\nu_\mu - \nu_s$ oscillation), the solar neutrino data via MSW mechanism (through $\nu_e - \nu_\tau$ oscillation), and the positive result of $\nu_\mu - \nu_e$ oscillation from LSND can be generated by this mechanism, whereas the vacuum oscillation solution to the solar neutrino problem is disfavored. We find that the electron and tau neutrino masses are of order $10^{-3}$ eV, and the muon neutrino and a sterile neutrino are almost maximally mixed to give a mass of order 1 eV. Two heavy sterile neutrinos have a mass of order 1 keV which can be obtained by the double seesaw mechanism with an intermediate mass scale $\sim 10^5$ GeV. A possible origin of such a scale is discussed.Comment: Revtex, 7 pages with 1 epsfig (uuencoded

Variations on Four-Neutrino Oscillations

We make a model-independent analysis of all available data that indicate neutrino oscillations. Using probability diagrams, we confirm that a mass spectrum with two nearly degenerate pairs of neutrinos separated by a mass gap of $\simeq1$ eV is preferred over a spectrum with one mass eigenstate separated from the others. We derive some new relations among the four-neutrino mixing matrix elements. We design four-neutrino mass matrices with three active neutrinos and one sterile neutrino that naturally incorporate maximal oscillations of atmospheric $\nu_\mu$ and explain the solar neutrino and LSND results. The models allow either a large or small angle MSW or vacuum oscillation description of the solar neutrino deficit. The models predict (i) oscillations of either $\nu_e \to \nu_\tau$ or $\nu_e \to\nu_s$ in long-baseline experiments at $L/E \gg 1$ km/GeV, with amplitude determined by the LSND oscillation amplitude and argument given by the atmospheric $\delta m^2$, and (ii) the equality of the $\nu_e$ disappearance probability, the $\nu_\mu$ disappearance probability, and the LSND $\nu_\mu\to\nu_e$ appearance probability in short-baseline experiments.Comment: Latex2.09, 40 pages, uses epsf.sty to include 8 postscript figure

Search for B⁺c decays to the pp‾π⁺ final state

A search for the decays of the B + c meson to pp-π + is performed for the first time using a data sample corresponding to an integrated luminosity of 3.0 fb -1 collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. No signal is found and an upper limit, at 95% confidence level, is set, fcfu×B(B + c →ppπ + ) < 3.6×10-8 in the kinematic region m(pp) < 2.85 GeV/c2, p T (B) < 20 GeV/c and 2.0 < y(B) < 4.5, where B is the branching fraction and f c (f u ) is the fragmentation fraction of the b quark into a B c + (B + ) meson