1,628 research outputs found

    How acceptable are antiretrovirals for the prevention of sexually transmitted HIV? A review of research on the acceptability of oral pre-exposure prophylaxis and treatment as prevention

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    Recent research has demonstrated how antiretrovirals (ARVs) could be effective in the prevention of sexually transmitted HIV. We review research on the acceptability of oral pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) for HIV prevention amongst potential users. We consider with whom, where and in what context this research has been conducted, how acceptability has been approached, and what research gaps remain. Findings from 33 studies show a lack of TasP research, PrEP studies which have focused largely on men who have sex with men (MSM) in a US context, and varied measures of acceptability. In order to identify when, where and for whom PrEP and TasP would be most appropriate and effective, research is needed in five areas: acceptability of TasP to people living with HIV; motivation for PrEP use and adherence; current perceptions and management of risk; the impact of broader social and structural factors; and consistent definition and operationalisation of acceptability which moves beyond adherence

    High-resolution mass models of dwarf galaxies from LITTLE THINGS

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    We present high-resolution rotation curves and mass models of 26 dwarf galaxies from LITTLE THINGS. LITTLE THINGS is a high-resolution Very Large Array HI survey for nearby dwarf galaxies in the local volume within 11 Mpc. The rotation curves of the sample galaxies derived in a homogeneous and consistent manner are combined with Spitzer archival 3.6 micron and ancillary optical U, B, and V images to construct mass models of the galaxies. We decompose the rotation curves in terms of the dynamical contributions by baryons and dark matter halos, and compare the latter with those of dwarf galaxies from THINGS as well as Lambda CDM SPH simulations in which the effect of baryonic feedback processes is included. Being generally consistent with THINGS and simulated dwarf galaxies, most of the LITTLE THINGS sample galaxies show a linear increase of the rotation curve in their inner regions, which gives shallower logarithmic inner slopes alpha of their dark matter density profiles. The mean value of the slopes of the 26 LITTLE THINGS dwarf galaxies is alpha =-0.32 +/- 0.24 which is in accordance with the previous results found for low surface brightness galaxies (alpha = -0.2 +/- 0.2) as well as the seven THINGS dwarf galaxies (alpha =-0.29 +/- 0.07). However, this significantly deviates from the cusp-like dark matter distribution predicted by dark-matter-only Lambda CDM simulations. Instead our results are more in line with the shallower slopes found in the Lambda CDM SPH simulations of dwarf galaxies in which the effect of baryonic feedback processes is included. In addition, we discuss the central dark matter distribution of DDO 210 whose stellar mass is relatively low in our sample to examine the scenario of inefficient supernova feedback in low mass dwarf galaxies predicted from recent Lambda SPH simulations of dwarf galaxies where central cusps still remain.Peer reviewe

    Searching for a Stochastic Background of Gravitational Waves with LIGO

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    The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is ΩGW<6.5×105\Omega_{\rm GW} < 6.5 \times 10^{-5}. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

    Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

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    Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

    Brief Report: Sensorimotor Gating in Idiopathic Autism and Autism Associated with Fragile X Syndrome

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    Prepulse inhibition (PPI) may useful for exploring the proposed shared neurobiology between idiopathic autism and autism caused by FXS. We compared PPI in four groups: typically developing controls (n = 18), FXS and autism (FXS+A; n = 15), FXS without autism spectrum disorder (FXS−A; n = 17), and idiopathic autism (IA; n = 15). Relative to controls, the FXS+A (p < 0.002) and FXS−A (p < 0.003) groups had impaired PPI. The FXS+A (p < 0.01) and FXS−A (p < 0.03) groups had lower PPI than the IA group. Prolonged startle latency was seen in the IA group. The differing PPI profiles seen in the FXS+A and IA indicates these groups may not share a common neurobiological abnormality of sensorimotor gating

    Onset and Progression of Behavioral and Molecular Phenotypes in a Novel Congenic R6/2 Line Exhibiting Intergenerational CAG Repeat Stability

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    In the present study we report on the use of speed congenics to generate a C57BL/6J congenic line of HD-model R6/2 mice carrying 110 CAG repeats, which uniquely exhibits minimal intergenerational instability. We also report the first identification of the R6/2 transgene insertion site. The relatively stable line of 110 CAG R6/2 mice was characterized for the onset of behavioral impairments in motor, cognitive and psychiatric-related phenotypes as well as the progression of disease-related impairments from 4 to 10 weeks of age. 110Q mice exhibited many of the phenotypes commonly associated with the R6/2 model including reduced activity and impairments in rotarod performance. The onset of many of the phenotypes occurred around 6 weeks and was progressive across age. In addition, some phenotypes were observed in mice as early as 4 weeks of age. The present study also reports the onset and progression of changes in several molecular phenotypes in the novel R6/2 mice and the association of these changes with behavioral symptom onset and progression. Data from TR-FRET suggest an association of mutant protein state changes (soluble versus aggregated) in disease onset and progression

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    CD4 count at presentation for HIV care in the United States and Canada: Are those over 50 years more likely to have a delayed presentation?

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    We assessed CD4 count at initial presentation for HIV care among ≥50-year-olds from 1997-2007 in 13 US and Canadian clinical cohorts and compared to <50-year-olds. 44,491 HIV-infected individuals in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) were included in our study. Trends in mean CD4 count (measured as cells/mm3) and 95% confidence intervals ([,]) were determined using linear regression stratified by age category and adjusted for gender, race/ethnicity, HIV transmission risk and cohort. From 1997-2007, the proportion of individuals presenting for HIV care who were ≥50-years-old increased from 17% to 27% (p-value < 0.01). The median CD4 count among ≥50 year-olds was consistently lower than younger adults. The interaction of age group and calendar year was significant (p-value <0.01) with both age groups experiencing modest annual improvements over time (< 50-year-olds: 5 [4 , 6] cells/mm3; ≥50-year-olds: 7 [5 , 9] cells/mm3), after adjusting for sex, race/ethnicity, HIV transmission risk group and cohort; however, increases in the two groups were similar after 2000. A greater proportion of older individuals had an AIDS-defining diagnosis at, or within three months prior to, first presentation for HIV care compared to younger individuals (13% vs. 10%, respectively). Due to the increasing proportion, consistently lower CD4 counts, and more advanced HIV disease in adults ≥50-year-old at first presentation for HIV care, renewed HIV testing efforts are needed
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