The emission by dust and stars of nearby galaxies in the Herschel KINGFISH survey

Using new far-infrared imaging from the Herschel Space Observatory with ancillary data from ultraviolet (UV) to submillimeter wavelengths, we estimate the total emission from dust and stars of 62 nearby galaxies in the KINGFISH survey in a way that is as empirical and model independent as possible. We collect and exploit these data in order to measure from the spectral energy distributions (SEDs) precisely how much stellar radiation is intercepted and re-radiated by dust, and how this quantity varies with galaxy properties. By including SPIRE data, we are more sensitive to emission from cold dust grains than previous analyses at shorter wavelengths, allowing for more accurate estimates of dust temperatures and masses. The dust/stellar flux ratio, which we measure by integrating the SEDs, has a range of nearly three decades (from 10(-2.2) to 10(0.5)). The inclusion of SPIRE data shows that estimates based on data not reaching these far-IR wavelengths are biased low by 17% on average. We find that the dust/stellar flux ratio varies with morphology and total infrared (IR) luminosity, with dwarf galaxies having faint luminosities, spirals having relatively high dust/stellar ratios and IR luminosities, and some early types having low dust/stellar ratios. We also find that dust/stellar flux ratios are related to gas-phase metallicity ((log(f(dust)/f(*)) over bar) = -0.66 +/- 0.08 and -0.22 +/- 0.12 for metal-poor and intermediate-metallicity galaxies, respectively), while the dust/stellar mass ratios are less so (differing by approximate to 0.2 dex); the more metal-rich galaxies span a much wider range of the flux ratios. In addition, the substantial scatter between dust/stellar flux and dust/stellar mass indicates that the former is a poor proxy of the latter. Comparing the dust/stellar flux ratios and dust temperatures, we also show that early types tend to have slightly warmer temperatures (by up to 5 K) than spiral galaxies, which may be due to more intense interstellar radiation fields, or possibly to different dust grain compositions. Finally, we show that early types and early-type spirals have a strong correlation between the dust/stellar flux ratio and specific star formation rate, which suggests that the relatively bright far-IR emission of some of these galaxies is due to ongoing (if limited) star formation as well as to the radiation field from older stars, which is heating the dust grains

SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

Fungal, bacterial and plant dsDNA contributions to soil total DNA extracted from silty soils under different farming practices: Relationships with chloroform-labile carbon

Twelve differently-managed silty soils from North-Western France were chosen to compare two common methods of quantifying soil microbial biomass: Chloroform fumigation and extraction-labile carbon (CL_C) and microbial double stranded DNA (dsDNA). We also determined the contributions of each of the fungal, bacterial, and plant kingdoms to the total community dsDNA using real-time Polymerase Chain Reaction with kingdom-specific ribosomal primer sets. Regardless of the method, the highest microbial biomasses were associated with long-term untilled plots. Site (locations) specificities could also be detected, especially in conventionally cultivated lands. Regardless of site, a strong linear relationship could be drawn between CL_C and dsDNA in tilled lands (r = 0.91, n = 15, P = 0.01) and in grasslands (r = 0.78, n = 21, P = 0.01). Moreover, we propose a logarithmic model describing all of our silty soils, irrespective of management. In order to explain the non-linearity (log) of this relationship, we tested the hypothesis of a weak plant dsDNA contribution in total dsDNA in comparison with the well-documented root cell contribution to CL_C quantifications. Plant dsDNA never exceeded 2.6% of total dsDNA content for all of the soils studied. Among groups examined, the bacterial dsDNA contribution to the community dsDNA pool was the most site- and/or pedoclimatic-dependent. Fungi constituted a major component of total microbial biomass in grassland or in land with permanent plant cover where their proportion reached almost 50% of total dsDNA. More precisely, fungal dsDNA concentration was highly related to tillage. Our study demonstrated the expediency of the total microbial dsDNA quantification in agricultural silty soils rather than the time-consuming quantification of CL_C. Quantifying the relative contribution of bacterial or fungal biomass in total dsDNA by real-time PCR allows to access to a new level of knowledge of the soil microbial biomass and to reveal the balances between those two kingdoms according to soils or farming practices

Filaments and ridges in Vela C revealed by Herschel: from low-mass to high-mass star-forming sites

7 pages + 2 page figure appendix, 8 Figures (one in the appendix). Accepted by A&A 2011International audienceWe present the first Herschel PACS and SPIRE results of the Vela C molecular complex in the far-infrared and submillimetre regimes at 70, 160, 250, 350, and 500 um, spanning the peak of emission of cold prestellar or protostellar cores. Column density and multi-resolution analysis (MRA) differentiates the Vela C complex into five distinct sub-regions. Each sub-region displays differences in their column density and temperature probability distribution functions (PDFs), in particular, the PDFs of the 'Centre-Ridge' and 'South-Nest' sub-regions appear in stark contrast to each other. The Centre-Ridge displays a bimodal temperature PDF representative of hot gas surrounding the HII region RCW 36 and the cold neighbouring filaments, whilst the South-Nest is dominated by cold filamentary structure. The column density PDF of the Centre-Ridge is flatter than the South-Nest, with a high column density tail, consistent with formation through large-scale flows, and regulation by self-gravity. At small to intermediate scales MRA indicates the Centre-Ridge to be twice as concentrated as the South-Nest, whilst on larger scales, a greater portion of the gas in the South-Nest is dominated by turbulence than in the Centre-Ridge. In Vela C, high-mass stars appear to be preferentially forming in ridges, i.e., dominant high column density filaments

COVID-19 Host Genetics Initiative. A first update on mapping the human genetic architecture of COVID-19

The COVID-19 pandemic continues to pose a major public health threat, especially in countries with low vaccination rates. To better understand the biological underpinnings of SARS-CoV-2 infection and COVID-19 severity, we formed the COVID-19 Host Genetics Initiative1. Here we present a genome-wide association study meta-analysis of up to 125,584 cases and over 2.5 million control individuals across 60 studies from 25 countries, adding 11 genome-wide significant loci compared with those previously identified2. Genes at new loci, including SFTPD, MUC5B and ACE2, reveal compelling insights regarding disease susceptibility and severity.</p