580 research outputs found
Environment of the submillimeter-bright massive starburst HFLS3 at 6.34
We describe the search for Lyman-break galaxies (LBGs) near the
sub-millimeter bright starburst galaxy HFLS3 at 6.34 and a study on the
environment of this massive galaxy during the end of reionization.We performed
two independent selections of LBGs on images obtained with the \textit{Gran
Telescopio Canarias} (GTC) and the \textit{Hubble Space Telescope} (HST) by
combining non-detections in bands blueward of the Lyman-break and color
selection. A total of 10 objects fulfilling the LBG selection criteria at
5.5 were selected over the 4.54 and 55.5 arcmin covered by our HST
and GTC images, respectively. The photometric redshift, UV luminosity, and the
star-formation rate of these sources were estimated with models of their
spectral energy distribution. These 6 candidates have physical
properties and number densities in agreement with previous results. The UV
luminosity function at 6 and a Voronoi tessellation analysis of this
field shows no strong evidence for an overdensity of relatively bright objects
(m25.9) associated with \textit{HFLS3}. However, the over-density
parameter deduced from this field and the surface density of objects can not
excluded definitively the LBG over-density hypothesis. Moreover we identified
three faint objects at less than three arcseconds from \textit{HFLS3} with
color consistent with those expected for 6 galaxies. Deeper data are
needed to confirm their redshifts and to study their association with
\textit{HFLS3} and the galaxy merger that may be responsible for the massive
starburst.Comment: 14 pages, 12 figures, accepted for publication in Ap
The Herschel Multi-tiered Extragalactic Survey: HerMES
The Herschel Multi-tiered Extragalactic Survey, HerMES, is a legacy program
designed to map a set of nested fields totalling ~380 deg^2. Fields range in
size from 0.01 to ~20 deg^2, using Herschel-SPIRE (at 250, 350 and 500 \mu m),
and Herschel-PACS (at 100 and 160 \mu m), with an additional wider component of
270 deg^2 with SPIRE alone. These bands cover the peak of the redshifted
thermal spectral energy distribution from interstellar dust and thus capture
the re-processed optical and ultra-violet radiation from star formation that
has been absorbed by dust, and are critical for forming a complete
multi-wavelength understanding of galaxy formation and evolution.
The survey will detect of order 100,000 galaxies at 5\sigma in some of the
best studied fields in the sky. Additionally, HerMES is closely coordinated
with the PACS Evolutionary Probe survey. Making maximum use of the full
spectrum of ancillary data, from radio to X-ray wavelengths, it is designed to:
facilitate redshift determination; rapidly identify unusual objects; and
understand the relationships between thermal emission from dust and other
processes. Scientific questions HerMES will be used to answer include: the
total infrared emission of galaxies; the evolution of the luminosity function;
the clustering properties of dusty galaxies; and the properties of populations
of galaxies which lie below the confusion limit through lensing and statistical
techniques.
This paper defines the survey observations and data products, outlines the
primary scientific goals of the HerMES team, and reviews some of the early
results.Comment: 23 pages, 17 figures, 9 Tables, MNRAS accepte
Longest Common Prefixes with -Errors and Applications
Although real-world text datasets, such as DNA sequences, are far from being
uniformly random, average-case string searching algorithms perform
significantly better than worst-case ones in most applications of interest. In
this paper, we study the problem of computing the longest prefix of each suffix
of a given string of length over a constant-sized alphabet that occurs
elsewhere in the string with -errors. This problem has already been studied
under the Hamming distance model. Our first result is an improvement upon the
state-of-the-art average-case time complexity for non-constant and using
only linear space under the Hamming distance model. Notably, we show that our
technique can be extended to the edit distance model with the same time and
space complexities. Specifically, our algorithms run in time on average using space. We show that our
technique is applicable to several algorithmic problems in computational
biology and elsewhere
Directional control of weakly localized Raman from a random network of fractal nanowires
Disordered optical media are an emerging class of materials capable of
strongly scattering light. Their study is relevant to investigate transport
phenomena and for applications in imaging, sensing and energy storage. While
such materials can be used to generate coherent light, their directional
emission is typically hampered by their very multiple scattering nature. Here,
we tune the out-of-plane directionality of coherent Raman light scattered by a
fractal network of silicon nanowires. By visualizing Rayleigh scattering,
photoluminescence and weakly localized Raman light from the random network of
nanowires via real-space microscopy and Fourier imaging, we gain insight on the
light transport mechanisms responsible for the material's inelastic coherent
signal and for its directionality. The possibility of visualizing and
manipulating directional coherent light in such networks of nanowires opens
venues for fundamental studies of light propagation in disordered media as well
as for the development of next generation optical devices based on disordered
structures, inclusive of sensors, light sources and optical switches
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Rab6 and Rab11 Regulate Chlamydia trachomatis Development and Golgin-84-Dependent Golgi Fragmentation
Many intracellular pathogens that replicate in special membrane bound compartments exploit cellular trafficking pathways by targeting small GTPases, including Rab proteins. Members of the Chlamydiaceae recruit a subset of Rab proteins to their inclusions, but the significance of these interactions is uncertain. Using RNA interference, we identified Rab6 and Rab11 as important regulators of Chlamydia infections. Depletion of either Rab6 or Rab11, but not the other Rab proteins tested, decreased the formation of infectious particles. We further examined the interplay between these Rab proteins and the Golgi matrix components golgin-84 and p115 with regard to Chlamydia-induced Golgi fragmentation. Silencing of the Rab proteins blocked Chlamydia-induced and golgin-84 knockdown-stimulated Golgi disruption, whereas Golgi fragmentation was unaffected in p115 depleted cells. Interestingly, p115-induced Golgi fragmentation could rescue Chlamydia propagation in Rab6 and Rab11 knockdown cells. Furthermore, transport of nutrients to Chlamydia, as monitored by BODIPY-Ceramide, was inhibited by Rab6 and Rab11 knockdown. Taken together, our results demonstrate that Rab6 and Rab11 are key regulators of Golgi stability and further support the notion that Chlamydia subverts Golgi structure to enhance its intracellular development
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Impact of high-risk prenatal screening results for 22q11.2 deletion syndrome on obstetric and neonatal management: Secondary analysis from the SMART study
Objective
One goal of prenatal genetic screening is to optimize perinatal care and improve infant outcomes. We sought to determine whether high-risk cfDNA screening for 22q11.2 deletion syndrome (22q11.2DS) affected prenatal or neonatal management.
Methods
This was a secondary analysis from the SMART study. Patients with high-risk cfDNA results for 22q11.2DS were compared with the low-risk cohort for pregnancy characteristics and obstetrical management. To assess differences in neonatal care, we compared high-risk neonates without prenatal genetic confirmation with a 1:1 matched low-risk cohort.
Results
Of 18,020 eligible participants enrolled between 2015 and 2019, 38 (0.21%) were high-risk and 17,982 (99.79%) were low-risk for 22q11.2DS by cfDNA screening. High-risk participants had more prenatal diagnostic testing (55.3%; 21/38 vs. 2.0%; 352/17,982, p < 0.001) and fetal echocardiography (76.9%; 10/13 vs. 19.6%; 10/51, p < 0.001). High-risk newborns without prenatal diagnostic testing had higher rates of neonatal genetic testing (46.2%; 6/13 vs. 0%; 0/51, P < 0.001), echocardiography (30.8%; 4/13 vs. 4.0%; 2/50, p = 0.013), evaluation of calcium levels (46.2%; 6/13 vs. 4.1%; 2/49, P < 0.001) and lymphocyte count (53.8%; 7/13 vs. 15.7%; 8/51, p = 0.008).
Conclusions
High-risk screening results for 22q11.2DS were associated with higher rates of prenatal and neonatal diagnostic genetic testing and other 22q11.2DS-specific evaluations. However, these interventions were not universally performed, and >50% of high-risk infants were discharged without genetic testing, representing possible missed opportunities to improve outcomes for affected individuals
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Cachd1 interacts with Wnt receptors and regulates neuronal asymmetry in the zebrafish brain.
Neurons on the left and right sides of the nervous system often show asymmetric properties, but how such differences arise is poorly understood. Genetic screening in zebrafish revealed that loss of function of the transmembrane protein Cachd1 resulted in right-sided habenula neurons adopting left-sided identity. Cachd1 is expressed in neuronal progenitors, functions downstream of asymmetric environmental signals, and influences timing of the normally asymmetric patterns of neurogenesis. Biochemical and structural analyses demonstrated that Cachd1 can bind simultaneously to Lrp6 and Frizzled family Wnt co-receptors. Consistent with this, lrp6 mutant zebrafish lose asymmetry in the habenulae, and epistasis experiments support a role for Cachd1 in modulating Wnt pathway activity in the brain. These studies identify Cachd1 as a conserved Wnt receptor-interacting protein that regulates lateralized neuronal identity in the zebrafish brain
The Leukemia-Associated Mllt10/Af10-Dot1l Are Tcf4/β-Catenin Coactivators Essential for Intestinal Homeostasis
The leukemia-associated Mllt10/Af10 and its partner the histone methyltransferase Dot1l are identified as Tcf4/β-catenin co-activators and shown to be essential for Wnt-driven endogenous gene expression, intestinal development and homeostasis
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