3,275 research outputs found
Sol immobilization technique: a delicate balance between activity, selectivity and stability of gold catalysts
HST Grism Observations of a Gravitationally Lensed Redshift 10 Galaxy
We present deep spectroscopic observations of a Lyman-break galaxy candidate
(hereafter MACS1149-JD) at with the Space
Telescope () WFC3/IR grisms. The grism observations were taken at
4 distinct position angles, totaling 34 orbits with the G141 grism, although
only 19 of the orbits are relatively uncontaminated along the trace of
MACS1149-JD. We fit a 3-parameter (, F160W mag, and Ly equivalent
width) Lyman-break galaxy template to the three least contaminated grism
position angles using an MCMC approach. The grism data alone are best fit with
a redshift of ( confidence), in
good agreement with our photometric estimate of
( confidence). Our analysis
rules out Lyman-alpha emission from MACS1149-JD above a equivalent
width of 21 \AA{}, consistent with a highly neutral IGM. We explore a scenario
where the red /IRAC color of the galaxy
previously pointed out in the literature is due to strong rest-frame optical
emission lines from a very young stellar population rather than a 4000 \AA{}
break. We find that while this can provide an explanation for the observed IRAC
color, it requires a lower redshift (), which is less preferred
by the imaging data. The grism data are consistent with both
scenarios, indicating that the red IRAC color can still be explained by a 4000
\AA{} break, characteristic of a relatively evolved stellar population. In this
interpretation, the photometry indicate that a Myr stellar
population is already present in this galaxy only after
the Big Bang.Comment: Accepted to ApJ. This is the accepted versio
The Grism Lens-Amplified Survey from Space (GLASS). V. Extent and spatial distribution of star formation in z~0.5 cluster galaxies
We present the first study of the spatial distribution of star formation in
z~0.5 cluster galaxies. The analysis is based on data taken with the Wide Field
Camera 3 as part of the Grism Lens-Amplified Survey from Space (GLASS). We
illustrate the methodology by focusing on two clusters (MACS0717.5+3745 and
MACS1423.8+2404) with different morphologies (one relaxed and one merging) and
use foreground and background galaxies as field control sample. The
cluster+field sample consists of 42 galaxies with stellar masses in the range
10^8-10^11 M_sun, and star formation rates in the range 1-20 M_sun/yr. Both in
clusters and in the field, H{\alpha} is more extended than the rest-frame UV
continuum in 60% of the cases, consistent with diffuse star formation and
inside out growth. In ~20% of the cases, the H{\alpha} emission appears more
extended in cluster galaxies than in the field, pointing perhaps to ionized gas
being stripped and/or star formation being enhanced at large radii. The peak of
the H{\alpha} emission and that of the continuum are offset by less than 1 kpc.
We investigate trends with the hot gas density as traced by the X-ray emission,
and with the surface mass density as inferred from gravitational lens models
and find no conclusive results. The diversity of morphologies and sizes
observed in H_alpha illustrates the complexity of the environmental process
that regulate star formation. Upcoming analysis of the full GLASS dataset will
increase our sample size by almost an order of magnitude, verifying and
strengthening the inference from this initial dataset.Comment: 18 pages, 15 figures, accepted for publication in Ap
The age-specific burden and household and school-based predictors of child and adolescent tuberculosis infection in rural Uganda.
BackgroundThe age-specific epidemiology of child and adolescent tuberculosis (TB) is poorly understood, especially in rural areas of East Africa. We sought to characterize the age-specific prevalence and predictors of TB infection among children and adolescents living in rural Uganda, and to explore the contribution of household TB exposure on TB infection.MethodsFrom 2015-2016 we placed and read 3,121 tuberculin skin tests (TST) in children (5-11 years old) and adolescents (12-19 years old) participating in a nested household survey in 9 rural Eastern Ugandan communities. TB infection was defined as a positive TST (induration â„10mm or â„5mm if living with HIV). Age-specific prevalence was estimated using inverse probability weighting to adjust for incomplete measurement. Generalized estimating equations were used to assess the association between TB infection and multi-level predictors.ResultsThe adjusted prevalence of TB infection was 8.5% (95%CI: 6.9-10.4) in children and 16.7% (95% CI:14.0-19.7) in adolescents. Nine percent of children and adolescents with a prevalent TB infection had a household TB contact. Among children, having a household TB contact was strongly associated with TB infection (aOR 5.5, 95% CI: 1.7-16.9), but the strength of this association declined among adolescents and did not meet significance (aOR 2.3, 95% CI: 0.8-7.0). The population attributable faction of TB infection due to a household TB contact was 8% for children and 4% among adolescents. Mobile children and adolescents who travel outside of their community for school had a 1.7 (95% CI 1.0-2.9) fold higher odds of TB infection than those who attended school in the community.ConclusionChildren and adolescents in this area of rural eastern Uganda suffer a significant burden of TB. The majority of TB infections are not explained by a known household TB contact. Our findings underscore the need for community-based TB prevention interventions, especially among mobile youth
HFF-DeepSpace photometric catalogs of the 12 Hubble frontier fields, clusters, and parallels : photometry, photometric redshifts, and stellar masses
We present Hubble multi-wavelength photometric catalogs, including (up to) 17 filters with the Advanced Camera for Surveys and Wide Field Camera 3 from the ultra-violet to near-infrared for the Hubble Frontier Fields and associated parallels. We have constructed homogeneous photometric catalogs for all six clusters and their parallels. To further expand these data catalogs, we have added ultra-deep KS-band imaging at 2.2. mu m from the Very Large Telescope HAWK-I and Keck-I MOSFIRE instruments. We also add post-cryogenic Spitzer imaging at 3.6 and 4.5. mu m with the Infrared Array Camera (IRAC), as well as archival IRAC 5.8 and 8.0. mu m imaging when available. We introduce the public release of the multi-wavelength (0.2-8 mu m) photometric catalogs, and we describe the unique steps applied for the construction of these catalogs. Particular emphasis is given to the source detection band, the contamination of light from the bright cluster galaxies (bCGs), and intra-cluster light (ICL). In addition to the photometric catalogs, we provide catalogs of photometric redshifts and stellar population properties. Furthermore, this includes all the images used in the construction of the catalogs, including the combined models of bCGs and ICL, the residual images, segmentation maps, and more. These catalogs are a robust data set of the Hubble Frontier Fields and will be an important aid in designing future surveys, as well as planning follow-up programs with current and future observatories to answer key questions remaining about first light, reionization, the assembly of galaxies, and many more topics, most notably by identifying high-redshift sources to target
Hypertension testing and treatment in Uganda and Kenya through the SEARCH study: An implementation fidelity and outcome evaluation.
BackgroundHypertension (HTN) is the single leading risk factor for human mortality worldwide, and more prevalent in sub-Saharan Africa than any other region [1]-although resources for HTN screening, treatment, and control are few. Most regional pilot studies to leverage HIV programs for HTN control have achieved blood pressure control in half of participants or fewer [2,3,4]. But this control gap may be due to inconsistent delivery of services, rather than ineffective underlying interventions.MethodsWe sought to evaluate the consistency of HTN program delivery within the SEARCH study (NCT01864603) among 95,000 adults in 32 rural communities in Uganda and Kenya from 2013-2016. To achieve this objective, we designed and performed a fidelity evaluation of the step-by-step process (cascade) of HTN care within SEARCH, calculating rates of HTN screening, linkage to care, and follow-up care. We evaluated SEARCH's assessment of each participant's HTN status against measured blood pressure and HTN history.FindingsSEARCH completed blood pressure screens on 91% of participants. SEARCH HTN screening was 91% sensitive and over 99% specific for HTN relative to measured blood pressure and patient history. 92% of participants screened HTN+ received clinic appointments, and 42% of persons with HTN linked to subsequent care. At follow-up, 82% of SEARCH clinic participants received blood pressure checks; 75% received medication appropriate for their blood pressure; 66% remained in care; and 46% had normal blood pressure at their most recent visit.ConclusionThe SEARCH study's consistency in delivering screening and treatment services for HTN was generally high, but SEARCH could improve effectiveness in linking patients to care and achieving HTN control. Its model for implementing population-scale HTN testing and care through an existing HIV test-and-treat program-and protocol for evaluating the intervention's stepwise fidelity and care outcomes-may be adapted, strengthened, and scaled up for use across multiple resource-limited settings
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HIV Incidence After Pre-Exposure Prophylaxis Initiation Among Women and Men at Elevated HIV Risk: A Population-Based Study in Rural Kenya and Uganda
Author summary Why was this study done? Despite major gains in HIV testing and treatment, there were 1.7 million new HIV infections worldwide in 2019, of which nearly 60% occurred in sub-Saharan Africa. Daily oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is highly effective for HIV prevention and could substantially reduce new HIV infections if offered alongside access to HIV testing and treatment. Little is known about the incidence of new HIV infections among PrEP users in settings with generalized HIV epidemics, particularly when offered broadly across communities where access to HIV testing and treatment have already been scaled up. What did the researchers do and find? In 16 communities in rural Kenya and Uganda, we conducted community-wide HIV testing and offered universal access to PrEP with an inclusive approach to eligibility (for persons in serodifferent partnerships, those identified by an HIV risk prediction tool, or those who self-identified as being at risk of HIV). We offered rapid PrEP start and a flexible care delivery model with follow-up visits at health facilities or community-based sites for HIV testing and PrEP refills. Of 74,541 persons who tested negative for HIV, 15,632 (21%) were assessed to be at elevated HIV risk, of whom 5,447 (35%) started PrEP. Overall, 79% of persons who initiated PrEP engaged in the program for follow-up visits. Among PrEP initiators in the 16 study communities, there were 25 seroconversions over 7,150 person-years of follow-up. HIV incidence was 0.35 per 100 person-years (95% confidence interval [CI] 0.22-0.49). In 8 communities, we compared HIV incidence among PrEP initiators to persons with similar characteristics (matched controls) from the year before PrEP was available. Compared to matched controls, HIV incidence was 74% lower among PrEP initiators overall; 76% lower among women who initiated PrEP; and 40% lower among men who initiated PrEP, although this result among men did not reach statistical significance. What do these findings mean? Providing universal access to PrEP in the context of community-wide HIV testing in rural Kenya and Uganda was associated with lower HIV incidence among persons who initiated PrEP compared to matched recent controls. We found lower HIV incidence after PrEP initiation among women, for whom rates of new HIV infections are higher than in men, including in recent prevention studies without PrEP. These results suggest that PrEP may help to close the gap in new infections between men and women. Universal access to HIV testing, treatment, and prevention, including rapid provision of PrEP with flexible service delivery, could reduce HIV incidence in generalized epidemic settings. Background Oral pre-exposure prophylaxis (PrEP) is highly effective for HIV prevention, but data are limited on HIV incidence among PrEP users in generalized epidemic settings, particularly outside of selected risk groups. We performed a population-based PrEP study in rural Kenya and Uganda and sought to evaluate both changes in HIV incidence and clinical and virologic outcomes following seroconversion on PrEP. Methods and findings During population-level HIV testing of individuals \u3e= 15 years in 16 communities in the Sustainable East Africa Research in Community Health (SEARCH) study (NCT01864603), we offered universal access to PrEP with enhanced counseling for persons at elevated HIV risk (based on serodifferent partnership, machine learning-based risk score, or self-identified HIV risk). We offered rapid or same-day PrEP initiation and flexible service delivery with follow-up visits at facilities or community-based sites at 4, 12, and every 12 weeks up to week 144. Among participants with incident HIV infection after PrEP initiation, we offered same-day antiretroviral therapy (ART) initiation and analyzed HIV RNA, tenofovir hair concentrations, drug resistance, and viral suppression (\u3c1,000 c/ml based on available assays) after ART start. Using Poisson regression with cluster-robust standard errors, we compared HIV incidence among PrEP initiators to incidence among propensity score-matched recent historical controls (from the year before PrEP availability) in 8 of the 16 communities, adjusted for risk group. Among 74,541 individuals who tested negative for HIV, 15,632/74,541 (21%) were assessed to be at elevated HIV risk; 5,447/15,632 (35%) initiated PrEP (49% female; 29% 15-24 years; 19% in serodifferent partnerships), of whom 79% engaged in \u3e= 1 follow-up visit and 61% self-reported PrEP adherence at \u3e= 1 visit. Over 7,150 person-years of follow-up, HIV incidence was 0.35 per 100 person-years (95% confidence interval [CI] 0.22-0.49) among PrEP initiators. Among matched controls, HIV incidence was 0.92 per 100 person-years (95% CI 0.49-1.41), corresponding to 74% lower incidence among PrEP initiators compared to matched controls (adjusted incidence rate ratio [aIRR] 0.26, 95% CI 0.09-0.75; p = 0.013). Among women, HIV incidence was 76% lower among PrEP initiators versus matched controls (aIRR 0.24, 95% CI 0.07-0.79; p = 0.019); among men, HIV incidence was 40% lower, but not significantly so (aIRR 0.60, 95% CI 0.12-3.05; p = 0.54). Of 25 participants with incident HIV infection (68% women), 7/25 (28%) reported taking PrEP \u3c= 30 days before HIV diagnosis, and 24/25 (96%) started ART. Of those with repeat HIV RNA after ART start, 18/19 (95%) had \u3c1,000 c/ml. One participant with viral non-suppression was found to have transmitted viral resistance, as well as emtricitabine resistance possibly related to PrEP use. Limitations include the lack of contemporaneous controls to assess HIV incidence without PrEP and that plasma samples were not archived to assess for baseline acute infection. Conclusions Population-level offer of PrEP with rapid start and flexible service delivery was associated with 74% lower HIV incidence among PrEP initiators compared to matched recent controls prior to PrEP availability. HIV infections were significantly lower among women who started PrEP. Universal HIV testing with linkage to treatment and prevention, including PrEP, is a promising approach to accelerate reductions in new infections in generalized epidemic settings
Phenology and Seasonal Ecosystem Productivity in an Amazonian Floodplain Forest
everal studies have explored the linkages between phenology and ecosystem productivity across the Amazon basin. However, few studies have focused on flooded forests, which correspond to c.a. 14% of the basin. In this study, we assessed the seasonality of ecosystem productivity (gross primary productivity, GPP) from eddy covariance measurements, environmental drivers and phenological patterns obtained from the field (leaf litter mass) and satellite measurements (enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer/multi-angle implementation correction (MODIS/MAIAC)) in an Amazonian floodplain forest. We found that ecosystem productivity is limited by soil moisture in two different ways. During the flooded period, the excess of water limits GPP (Spearmanâs correlation; rho = â0.22), while during non-flooded months, GPP is positively associated with soil moisture (rho = 0.34). However, GPP is maximized when cumulative water deficit (CWD) increases (rho = 0.81), indicating that GPP is dependent on the amount of water available. EVI was positively associated with leaf litter mass (Pearsonâs correlation; r = 0.55) and with GPP (r = 0.50), suggesting a coupling between new leaf production and the phenology of photosynthetic capacity, decreasing both at the peak of the flooded period and at the end of the dry season. EVI was able to describe the inter-annual variations on forest responses to environmental drivers, which have changed during an observed El Niño-Southern Oscillation (ENSO) year (2015/2016)
Transcriptomic profiling of skeletal muscle adaptations to exercise and inactivity
The authors are supported by grants from the Novo Nordisk Foundation (NNF14OC0011493, NNF17OC0030088 and NNF14OC0009941), Swedish Diabetes Foundation (DIA2018-357, DIA2018-336), Swedish Research Council (2015-00165, 2018-02389), the Strategic Research Program in Diabetes at Karolinska Institutet (2009-1068), the Stockholm County Council (SLL20150517, SLL20170159), the Swedish Research Council for Sport Science (P2018-0097), and the EFSD European Research Programme on New Targets for Type 2 Diabetes supported by an educational research grant from MSD. L.D. was supported by a Novo Nordisk postdoctoral fellowship run in partnership with Karolinska Institutet. B.M.G. was supported by a fellowship from the Wenner-Gren Foundation (Sweden). N.J.P. was supported by an Individual Fellowship from the Marie SkĆodowska-Curie Actions (European Commission, 704978, 675610) and grants from the Sigurd och Elsa Goljes Minne and Lars Hiertas Minne Foundations (Sweden). D.J.B. was supported by the ANZ Mason Foundation and Australian Research Council Discovery Program (ARC DP140104165). Additional support was received from the Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen (NNF18CC0034900) (to J.R.Z.). We thank Dr. Nanjiang Shu from National Bioinformatics Infrastructure Sweden (NBIS) for setting up the web-server. We also thank EGI federated cloud for providing the computer resource for hosting the web-server. We acknowledge the Beta Cell in-vivo Imaging/Extracellular Flux Analysis core facility supported by the Strategic Research Program (SRP) in Diabetes for the usage of the Seahorse flux analyzer. Open access funding provided by Karolinska Institute.Peer reviewedPublisher PD
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