616 research outputs found

    Postpartum HIV care continuum outcomes in the southeastern USA

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    The aim of this study was to evaluate postpartum HIV care outcomes.Design:A prospective clinical cohort of women with HIV and a live birth at the University of North Carolina, 1996-2014.Methods:We estimated two stages of the HIV care continuum in the first 24 months postpartum: care retention (at least two visits per year, ≥90 days apart) and viral suppression (HIV RNA<400copies/ml). Multivariable models were fit using logistic regression.Results:Among 1416 women, 141 experienced a live birth at a median age of 28 years, with 74% virally suppressed at delivery. Among all women, 48% were retained in care and 25% maintained viral suppression for the first 24 months postpartum. Among women with available HIV RNA measures, 42% were suppressed at 24 months. HIV care retention estimates were stable across calendar years, but viral suppression rates at 24 months postpartum, among women with available HIV RNA measures, increased from 33 to 67% from 1996-2001 to 2009-2014 (P=0.04). Being at least 30 years old was positively, and receiving less than 12 weeks of antenatal antiretroviral therapy was negatively, associated with HIV care retention at 24 months postpartum [adjusted odds ratio (AOR): 2.41, 95% confidence interval (95% CI): 1.09-5.29 and AOR: 0.27, 95% CI: 0.08-0.86]. Older maternal age and viral suppression at delivery were both positively associated with virologic suppression at 24 months postpartum (AOR: 2.52, CI: 1.02-6.22, and AOR: 6.42 CI: 1.29-31.97, respectively).Conclusion:HIV care continuum outcomes decrease substantially postpartum, with younger women and those with less antenatal HIV care less likely to successfully remain engaged in HIV care following childbirth

    First Observation of Coherent π0\pi^0 Production in Neutrino Nucleus Interactions with Eν<E_{\nu}< 2 GeV

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    The MiniBooNE experiment at Fermilab has amassed the largest sample to date of π0\pi^0s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of π0\pi^0s produced in mineral oil (CH2_2) and the first observation of coherent π0\pi^0 production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 ±\pm1.1 (stat) ±\pm2.5 (sys))% of all exclusive NC π0\pi^0 production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for νμνe\nu_{\mu} \to \nu_e oscillations.Comment: Submitted to Phys. Lett.

    Functional diversity of chemokines and chemokine receptors in response to viral infection of the central nervous system.

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    Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

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    The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

    Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

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    A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

    Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

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    Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

    Seasonal cycle of CO2 from the sea ice edge to island blooms in the Scotia Sea, Southern Ocean

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    The Scotia Sea region contains some of the most productive waters of the Southern Ocean. It is also a dynamic region through the interaction of deep water masses with the atmosphere. We present a first seasonally-resolved time series of the fugacity of CO2 (fCO2) from spring 2006, summer 2008, autumn 2009 and winter (potential temperature minimum) along a 1000 km transect from the pack ice to the Polar Front to quantify the effects of biology and temperature on oceanic fCO2. Substantial spring and summer decreases in sea surface fCO2 occurred in phytoplankton blooms that developed in the naturally iron fertilised waters downstream (north) of South Georgia island (54-55S, 36-38W) and following sea ice melt (in the seasonal ice zone). The largest seasonal fCO2 amplitude (fCO2) of 159 uatm was found in the South Georgia bloom. In this region, biological carbon uptake dominated the seasonal signal, reducing the winter maxima in oceanic fCO2 by 257 uatm by the summer. In the Weddell-Scotia Confluence, the southern fringe of the Scotia Sea, the shift from wintertime CO2-rich conditions in ice covered waters to CO2 undersaturation in the spring blooms during and upon sea ice melt created strong seasonality in oceanic fCO2. Temperature effects on oceanic fCO2 ranged from fCO2sst of 55 uatm in the seasonal ice zone to almost double that downstream of South Georgia (98 uatm). The seasonal cycle of surface water fCO2 in the high-nutrient low-chlorophyll region of the central Scotia Sea had the weakest biological control and lowest seasonality. Basin-wide biological processes dominated the seasonal control on oceanic fCO2 (fCO2bio of 159 μatm), partially compensated (43%) by moderate temperature control (fCO2sst of 68 μatm). The patchwork of productivity across the Scotia Sea creates regions of seasonally strong biological uptake of CO2 in the Southern Ocean
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