753 research outputs found
Low prevalence of hepatitis C co-infection in recently HIV-infected minority men who have sex with men in Los Angeles: a cross-sectional study.
BackgroundGeographic and sociodemographic characterization of hepatitis C virus (HCV) transmission amongst men who have sex with men (MSM) has been limited. Our aim was to characterize HCV prevalence, risk factors for HCV co-infection, and patterns of HIV and HCV co-transmission and transmitted drug resistance mutations (DRMs) in newly HIV-diagnosed Los Angeles MSM.MethodsViral RNA was extracted from stored plasma samples from a Los Angeles cohort of newly diagnosed HIV-infected MSM with well-characterized substance use and sexual behavioral characteristics via computer-assisted self-interviewing surveys. Samples were screened for HCV by qPCR. HCV E1, E2, core, NS3 protease and NS5B polymerase and HIV-1 protease and reverse transcriptase regions were amplified and sequenced. Phylogenetic analysis was used to determine relatedness of HCV and HIV-1 isolates within the cohort and viral sequences were examined for DRMs.ResultsOf 185 newly HIV-diagnosed MSM, the majority (65%) were of minority race/ethnicity and recently infected (57.8%), with median age of 28.3 years. A minority (6.6%) reported injection drug use (IDU), whereas 96 (52.8%) reported recent substance use, primarily cannabis or stimulant use. High risk sexual behaviors included 132 (74.6%) with unprotected receptive anal intercourse, 60 (33.3%) with group sex, and 10 (5.7%) with fisting. Forty-five (24.3%) had acute gonorrhea or chlamydia infection. Only 3 (1.6%) subjects had detectable HCV RNA. Amongst these subjects, HIV and HCV isolates were unrelated by phylogenetic analysis and none possessed clinically relevant NS3 or NS5B HCV DRMs.ConclusionsPrevalence of HCV co-infection was low and there was no evidence of HIV-HCV co-transmission in this cohort of relatively young, predominantly minority, newly HIV-diagnosed MSM, most with early HIV infection, with high rates of high risk sexual behaviors, STI, and non-IDU. The low HCV prevalence in a group with high-risk behaviors for non-IDU HCV acquisition suggests an opportune time for targeted HCV prevention measures
High Spatial Resolution Spectroscopy of W51 IRS2E and IRS2W: Two Very Massive Young Stars in Early Formation Stages
We present -band spectra of the near infrared counterparts to IRS2E and
IRS2W which is associated with the ultracompact HII region W51d, both of them
embedded sources in the Galactic compact HII region W51 IRS2. The high spatial
resolution observations were obtained with the laser guide star facility and
Near infrared Integral Field Spectrograph (NIFS) mounted at the Gemini North
observatory. The spectrum of the ionizing source of W51d shows the photospheric
features NIII (21155 \AA) in emission and HeII (21897 \AA) in absorption which
lead us to classify it as an young O3 type star. We detected CO overtone in
emission at 23000 \AA in the spectrum of IRS2E, suggesting that it is a massive
young object still surrounded by an accretion disc, probably transitioning from
the hot core phase to an ultracompact HII region.Comment: Accepted by ApJ Letter
Marching to a different drummer : a cross-cultural comparison of young adolescents who challenge gender norms
Purpose: Little is known about how gender norms regulate adolescents' lives across different cultural settings. This study aims to illustrate what is considered as violating gender norms for boys and girls in four urban poor sites as well as the consequences that follow the challenging of gender norms.
Methods: Data were collected as part of the Global Early Adolescent Study, a 15-country collaboration to explore gender norms and health in early adolescence. The current study analyzed narrative and in-depth interviews conducted in urban poor sites in two middle-income (Shanghai, China; and New Delhi, India) and two high-income countries (Baltimore, U.S.; and Ghent, Belgium). A total of 238 participants, 59 boys and 70 girls aged 11-13 years old and 109 of their parents/guardians (28 male adults and 81 female adults), were interviewed. A thematic analysis was conducted across sites using Atlas. Ti 7.5 software.
Results: Findings revealed that although most perceptions and expressions about gender were regulated by stereotypical norms, there was a growing acceptability for girls to wear boyish clothes and engage in stereotypical masculine activities such as playing soccer/football. However, there was no comparable acceptance of boys engaging in traditional feminine behaviors. Across all sites, challenging gender norms was often found to lead to verbal, physical, and/or psychological retribution.
Conclusions: While it is sometimes acceptable for young adolescents to cross gender boundaries, once it becomes clear that a behavior is socially defined as typical for the other sex, and the adolescent will face more resistance. Researchers, programmers, and clinicians working in the field of adolescent health need not only attend to those who are facing the consequences of challenging prevailing gender norms, but also to address the environment that fosters exclusion and underscores differences
High-accuracy differential image motion monitor measurements for the Thirty Meter Telescope site testing program
Differential image motion monitors (DIMMs) have become the industry standard for astronomical site characterization. The calibration of DIMMs is generally considered to be routine, but we show that particular care must be paid to this issue if high-accuracy measurements are to be achieved. In a side by side comparison of several DIMMs, we demonstrate that with proper care we can achieve an agreement between the seeing measurements of two DIMMS operating under the same conditions to better than ±0.02 arc sec
Accurate distance control between a probe and a surface using a microcantilever
We demonstrate a method to accurately control the distance between a custom
probe and a sample on a {\mu}m to nm scale. The method relies on the
closed-loop feedback on the angular deflection of an in-contact AFM
microcantilever. High performance in stability and accuracy is achieved in this
method by taking advantage of the small mechanical feedback path between
surface and probe. We describe how internal error sources that find their
origin in the microcantilever and feedback can be minimized to achieve an
accurate and precise control up to 3 nm. In particular, we investigated how
hysteresis effects in the feedback caused by friction forces between tip and
substrate, can be minimized. By applying a short calibration procedure,
distance control from contact to several micrometers probe-sample distance can
be obtained with an absolute nanometer-scale accuracy. The method presented is
compatible with any probe that can be fixed on a microcantilever chip and can
be easily built into existing AFM systems
SMASHing the LMC: A Tidally-induced Warp in the Outer LMC and a Large-scale Reddening Map
We present a study of the three-dimensional (3D) structure of the Large
Magellanic Cloud (LMC) using ~2.2 million red clump (RC) stars selected from
the Survey of the MAgellanic Stellar History. To correct for line-of-sight dust
extinction, the intrinsic RC color and magnitude and their radial dependence
are carefully measured by using internal nearly dust-free regions. These are
then used to construct an accurate 2D reddening map (165 square degrees with
~10 arcmin resolution) of the LMC disk and the 3D spatial distribution of RC
stars. An inclined disk model is fit to the 2D distance map yielding a best-fit
inclination angle i = 25.86(+0.73,-1.39) degrees with random errors of +\-0.19
degrees and line-of-nodes position angle theta = 149.23(+6.43,-8.35) degrees
with random errors of +/-0.49 degrees. These angles vary with galactic radius,
indicating that the LMC disk is warped and twisted likely due to the repeated
tidal interactions with the Small Magellanic Cloud (SMC). For the first time,
our data reveal a significant warp in the southwestern part of the outer disk
starting at rho ~ 7 degrees that departs from the defined LMC plane up to ~4
kpc toward the SMC, suggesting that it originated from a strong interaction
with the SMC. In addition, the inner disk encompassing the off-centered bar
appears to be tilted up to 5-15 degrees relative to the rest of the LMC disk.
These findings on the outer warp and the tilted bar are consistent with the
predictions from the Besla et al. simulation of a recent direct collision with
the SMC.Comment: 25 pages, 15 figures, published in Ap
The inappropriateness of conventional cephalometrics
1. 1. Cephalometric conventions today may have little basis in either biology or biometrics.2. 2. There is no theory of cephalometrics, only conventions which involve landmarks and straight lines only. These fail to capture the curving of form and its changes, exclude proper measures of size for bent structures, and misrepresent growth, portraying it as vector displacement rather than a generalized distortion.3. 3. Conventional cephalometric procedures misinform by fabrication of misleading geometric quantities, by camouflage, particularly of remodeling, by confusion about what is happening (analysis of rotations, treating shape separately from size, and registering angles on landmarks as vertices), and by subtraction as a representation of growth.4. 4. We suggest that the present systems offer little real hope of improvement sufficient to meet our needs in craniofacial growth research. We call attention to three possible techniques to be included in future cephalometric conventions: (1) tangents and curvatures, (2) Blum's medial axis ("skeleton"), and (3) biorthogonal grids.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23746/1/0000718.pd
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