347 research outputs found
Altered expiratory flow dynamics at peak exercise in adult men with well-controlled type 1 diabetes.
Peer reviewe
The Association between Cardiorespiratory Fitness and Gut Microbiota Composition in Premenopausal Women
The aim of this study was to investigate the association between cardiorespiratory fitness and gut microbiota composition in premenopausal women. The participants consisted of 71 premenopausal Finnish women ( aged 19-49 years). Gut microbiota were analyzed using flow cytometry, 16S rRNA gene hybridization and DNA-staining. Maximum oxygen uptake (VO2max) was assessed by respiratory gas analyzer and body composition by Bioimpdance. We found that participants with low VO2max had lower Bacteroides, but higher Eubacterium rectale-Clostridium coccoides than the high VO2max group (p < 0.05 for all). VO2max was inversely associated with EreC (r = 0.309, p = 0.01) but not with other bacteria. VO2max also negatively correlated with fat% (r = 0.755, p < 0.001), triglycerides (r = -0.274, p = 0.021) and leptin (r = -0.574, p < 0.001). By contrast, EreC was positively associated with fat% (r = 0.382, p = 0.002), dietary fat intake (r = 0.258, p = 0.034), triglycerides (r = 0.390, p = 0.002) and leptin (r = 0.424, p = 0.001), but negatively with carbohydrate intake (r = -0.252, p = 0.034) and HDL (r = -0.26, p = 0.028). After adjusting for age and dietary intake, all the significant associations remained. However, after adjusting for fat%, the associations between VO2max and EreC disappeared. Our results suggest that cardiorespiratory fitness is associated with gut microbiota composition, independent of age and carbohydrate or fat intake. The association between VO2max and EreC, however, appears to be mediated by body fatness
Insights into the O : C-dependent mechanisms controlling the evaporation of α-pinene secondary organic aerosol particles
The volatility of oxidation products of volatile organic
compounds (VOCs) in the atmosphere is a key factor to determine if they
partition into the particle phase contributing to secondary organic aerosol
(SOA) mass. Thus, linking volatility and measured particle composition will
provide insights into SOA formation and its fate in the atmosphere. We
produced α-pinene SOA with three different oxidation levels
(characterized by average oxygen-to-carbon ratio; O:C‾=0.53, 0.69, and 0.96) in an oxidation flow reactor. We investigated the
particle volatility by isothermal evaporation in clean air as a function of
relative humidity (RH <2 %, 40 %, and 80 %) and used a
filter-based thermal desorption method to gain volatility and chemical
composition information.
We observed reduced particle evaporation for particles with increasing
O:C‾ ratio, indicating that particles become more resilient to evaporation with
oxidative aging. Particle evaporation was increased in the presence of water
vapour and presumably particulate water; at the same time the resistance of
the residual particles to thermal desorption was increased as well. For SOA
with O:C‾=0.96, the unexpectedly large increase in mean thermal desorption
temperature and changes in the thermogram shapes under wet conditions
(80 % RH) were an indication of aqueous phase chemistry. For the lower
O:C‾ cases, some water-induced composition changes were observed. However, the
enhanced evaporation under wet conditions could be explained by the
reduction in particle viscosity from the semi-solid to liquid-like range, and
the observed higher desorption temperature of the residual particles is a
direct consequence of the increased removal of high-volatility and the
continued presence of low-volatility compounds.</p
Uncovering the stellar structure of the dusty star-forming galaxy GN20 at z=4.055 with MIRI/JWST
Luminous infrared galaxies at high redshifts (>4) include extreme
starbursts that build their stellar mass over short periods of time (>100 Myr).
These galaxies are considered to be the progenitors of massive quiescent
galaxies at intermediate redshifts (2) but their stellar structure and
buildup is unknown. Here, we present the first spatially resolved near-infrared
imaging of GN20, one of the most luminous dusty star-forming galaxies known to
date, observed at an epoch when the Universe was only 1.5 Gyr old. The
5.6m image taken with the JWST Mid-Infrared Instrument (MIRI/JWST) shows
that GN20 is a very luminous galaxy (M=25.01), with a
stellar structure composed of a conspicuous central source and an extended
envelope. The central source is an unresolved nucleus that carries 9% of the
total flux. The nucleus is co-aligned with the peak of the cold dust emission,
and offset by 3.9 kpc from the ultraviolet stellar emission. The diffuse
stellar envelope is similar in size to the clumpy CO molecular gas
distribution. The centroid of the stellar envelope is offset by 1 kpc from the
unresolved nucleus, suggesting GN20 is involved in an interaction or merger
event supported by its location as the brightest galaxy in a proto-cluster. The
stellar size of GN20 is larger by a factor of about 3-5 than known spheroids,
disks, and irregulars at 4, while its size and low S\'ersic index are
similar to those measured in dusty, infrared luminous galaxies at 2 of
the same mass. GN20 has all the ingredients necessary for evolving into a
massive spheroidal quiescent galaxy at intermediate : it is a large,
luminous galaxy at =4.05 involved in a short and massive starburst centred
in the stellar nucleus and extended over the entire galaxy, out to radii of 4
kpc, and likely induced by the interaction or merger with a member of the
proto-cluster.Comment: 7 pages, 4 figure
Strong (Hb + [OIII]) and Ha emitters at redshift z ~ 7-8 unveiled with JWST/NIRCam and MIRI imaging in the Hubble eXtreme Deep Field (XDF)
The JWST is revolutionizing the study of high-redshift galaxies by providing
for the first time a high-sensitivity view of the early Universe at infrared
wavelengths, both with its Near Infrared Camera (NIRCam) and Mid Infrared
Instrument (MIRI). In this paper, we make use of medium and broad-band NIRCam
imaging, as well as ultra-deep MIRI 5.6 microns imaging, in the Hubble eXtreme
Deep Field (XDF) to identify prominent line emitters at z ~ 7-8. Out of a total
of 58 galaxies at z ~ 7-8, we find 18 robust candidates (~31%) for prominent
(Hb + [OIII]) emitters, based on their enhanced fluxes in the F430M and F444W
filters, with rest-frame EW(Hb + [OIII]) ~ 87 - 2100 A. Among these emitters,
16 lie on the MIRI coverage area and 12 show a clear flux excess at 5.6
microns, indicating the simultaneous presence of a prominent Ha emission line
with rest-frame EW(Ha) ~ 200 - 3000 A. This is the first time that Ha emission
can be detected in individual galaxies at z>7. The Ha line, when present,
allows us to separate the contributions of the Hb and [OIII] emission lines to
the (Hb + [OIII]) complex and derive Ha-based star formation rates (SFRs). We
find that in some cases [OIII]/Hb > 1, suggesting low metallicities, but a few
have [OIII]/Hb < 1, so the NIRCam flux excess is mainly driven by Hb. The vast
majority of prominent line emitters are very young starbursts or galaxies on
their way to/from the starburst cloud. They make for a cosmic SFR density
log10(SFRD_Ha / Msun yr^-1 Mpc^-3) ~ 2.35, which is about a third of the total
value at z ~ 7-8. Therefore, the strong Ha emitters likely had an important
role in reionization.Comment: 15 pages, 9 figures. Submitted to Ap
A comprehensive 1000 Genomes-based genome-wide association meta-analysis of coronary artery disease
Existing knowledge of genetic variants affecting risk of coronary artery disease (CAD) is largely based on genome-wide association studies (GWAS) analysis of common SNPs. Leveraging phased haplotypes from the 1000 Genomes Project, we report a GWAS meta-analysis of 185 thousand CAD cases and controls, interrogating 6.7 million common (MAF>0.05) as well as 2.7 million low frequency (0.005<MAF<0.05) variants. In addition to confirmation of most known CAD loci, we identified 10 novel loci, eight additive and two recessive, that contain candidate genes that newly implicate biological processes in vessel walls. We observed intra-locus allelic heterogeneity but little evidence of low frequency variants with larger effects and no evidence of synthetic association. Our analysis provides a comprehensive survey of the fine genetic architecture of CAD showing that genetic susceptibility to this common disease is largely determined by common SNPs of small effect siz
Demographic histories and genetic diversities of Fennoscandian marine and landlocked ringed seal subspecies
Peer reviewe
Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A
The nearby Supernova 1987A was accompanied by a burst of neutrino emission, which indicates that a compact object (a neutron star or black hole) was formed in the explosion. There has been no direct observation of this compact object. In this work, we observe the supernova remnant with JWST spectroscopy, finding narrow infrared emission lines of argon and sulfur. The line emission is spatially unresolved and blueshifted in velocity relative to the supernova rest frame. We interpret the lines as gas illuminated by a source of ionizing photons located close to the center of the expanding ejecta. Photoionization models show that the line ratios are consistent with ionization by a cooling neutron star or a pulsar wind nebula. The velocity shift could be evidence for a neutron star natal kick
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