43 research outputs found
Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic Average IMF Slope is Similar to the Salpeter IMF
The stellar initial mass function (IMF) is expressed by with the slope , and known as the poorly-constrained but
very important function in studies of star and galaxy formation. There are no
sensible observational constraints on the IMF slopes beyond Milky Way and
nearby galaxies. Here we combine two sets of observational results, 1) cosmic
densities of core-collapse supernova explosion (CCSNe) rates and 2) cosmic far
ultraviolet radiation (and infrared re-radiation) densities, which are
sensitive to massive () and moderately massive
() stars, respectively, and constrain the IMF
slope at with a freedom of redshift evolution. Although no
redshift evolution is identified beyond the uncertainties, we find that the
cosmic average IMF slope at is at the 95 % confidence
level that is comparable with the Salpeter IMF, , which marks the
first constraint on the cosmic average IMF. We show a forecast for the Nancy
Grace Roman Space Telescope supernova survey that will provide significantly
strong constraints on the IMF slope with over
. Moreover, as for an independent IMF probe instead of 1), we suggest to
use diffuse supernovae neutrino background (DSNB), relic neutrinos from CCSNe.
We expect that the Hyper-Kamiokande neutrino observations over 20 years will
improve the constraints on the IMF slope and the redshift evolution
significantly better than those obtained today, if the systematic uncertainties
of DSNB production physics are reduced in the future numerical simulations.Comment: 7 pages, 6 figures, ApJ in pres
Arukikata Travelogue Dataset with Geographic Entity Mention, Coreference, and Link Annotation
Geoparsing is a fundamental technique for analyzing geo-entity information in
text. We focus on document-level geoparsing, which considers geographic
relatedness among geo-entity mentions, and presents a Japanese travelogue
dataset designed for evaluating document-level geoparsing systems. Our dataset
comprises 200 travelogue documents with rich geo-entity information: 12,171
mentions, 6,339 coreference clusters, and 2,551 geo-entities linked to
geo-database entries
Association between the tissue accumulation of advanced glycation end products and exercise capacity in cardiac rehabilitation patients
Background Advanced glycation end products (AGEs) are associated with aging, diabetes mellitus (DM), and other chronic diseases. Recently, the accumulation of AGEs can be evaluated by skin autofluorescence (SAF). However, the relationship between SAF levels and exercise capacity in patients with cardiovascular disease (CVD) remains unclear. This study aimed to investigate the association between the tissue accumulation of AGEs and clinical characteristics, including exercise capacity, in patients with CVD. Methods We enrolled 319 consecutive CVD patients aged >= 40 years who underwent early phase II cardiac rehabilitation (CR) at our university hospital between November 2015 and September 2017. Patient background, clinical data, and the accumulation of AGEs assessed by SAF were recorded at the beginning of CR. Characteristics were compared between two patient groups divided according to the median SAF level (High SAF and Low SAF). Results The High SAF group was significantly older and exhibited a higher prevalence of DM than the Low SAF group. The sex ratio did not differ between the two groups. AGE levels showed significant negative correlations with peak oxygen uptake and ventilator efficiency (both P <0.0001). Exercise capacity was significantly lower in the high SAF group than in the low SAF group, regardless of the presence or absence of DM (P <0.05). A multivariate logistic regression analysis showed that SAF level was an independent factor associated with reduced exercise capacity (odds ratio 2.10; 95% confidence interval 1.13-4.05; P = 0.02). Conclusion High levels of tissue accumulated AGEs, as assessed by SAF, were significantly and independently associated with reduced exercise capacity. These data suggest that measuring the tissue accumulation of AGEs may be useful in patients who have undergone CR, irrespective of whether they have DM
EMPRESS. IX. Extremely Metal-Poor Galaxies are Very Gas-Rich Dispersion-Dominated Systems: Will JWST Witness Gaseous Turbulent High-z Primordial Galaxies?
We present kinematics of 6 local extremely metal-poor galaxies (EMPGs) with
low metallicities () and low stellar masses
(). Taking deep medium-high resolution
() integral-field spectra with 8.2-m Subaru, we resolve the small
inner velocity gradients and dispersions of the EMPGs with H emission.
Carefully masking out sub-structures originated by inflow and/or outflow, we
fit 3-dimensional disk models to the observed H flux, velocity, and
velocity-dispersion maps. All the EMPGs show rotational velocities () of 5--23 km s smaller than the velocity dispersions
() of 17--31 km s, indicating dispersion-dominated () systems affected by inflow and/or outflow. Except
for two EMPGs with large uncertainties, we find that the EMPGs have very large
gas-mass fractions of . Comparing our results with
other H kinematics studies, we find that
decreases and increases with decreasing metallicity, decreasing
stellar mass, and increasing specific star-formation rate. We also find that
simulated high- () forming galaxies have gas fractions and dynamics
similar to the observed EMPGs. Our EMPG observations and the simulations
suggest that primordial galaxies are gas-rich dispersion-dominated systems,
which would be identified by the forthcoming James Webb Space Telescope (JWST)
observations at .Comment: Submitted to ApJ; After revisio
Low Docosahexaenoic Acid, Dihomo-Gamma-Linolenic Acid, and Arachidonic Acid Levels Associated with Long-Term Mortality in Patients with Acute Decompensated Heart Failure in Different Nutritional Statuses
The clinical significance of polyunsaturated fatty acids (PUFAs) in acute decompensated heart failure (ADHF) in various nutritional statuses remains unclear. For this study, we enrolled 267 patients with ADHF admitted to the cardiac intensive care unit at Juntendo University hospital between April 2012 and March 2014. The association between long-term mortality, the geriatric nutritional risk index (GNRI), and levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), dihomo-gamma-linolenic acid (DGLA), and arachidonic acid (AA) was investigated. The median age was 73 (64β82) years, and mortality was 29% (62 patients). The event-free survival rates for all-cause death were higher in patients with high PUFA levels or GNRI than in those with low PUFA levels or GNRI (p < 0.05 for all). In particular, high DGLA in the low-GNRI group and high DHA or AA in the high-GNRI group were associated with high event-free survival (p < 0.05 for all). After accounting for confounding variables, DHA, DGLA, and AA, but not EPA, were associated with long-term mortality (p < 0.01 for all). This study concludes that in patients with ADHF, decreased levels of DHA, DGLA, and AA are independently associated with long-term mortality in the various nutritional statuses
Template-Assisted Selective Radical Addition toward Sequence-Regulated Polymerization: Lariat Capture of Target Monomer by Template Initiator
Living Cationic Polymerization of an Azide-Containing Vinyl Ether toward Addressable Functionalization of Polymers
Stellar Initial Mass Function (IMF) Probed with Supernova Rates and Neutrino Background: Cosmic-average IMF Slope Is β2β3 Similar to the Salpeter IMF
The stellar initial mass function (IMF) is expressed by Ο ( m ) β m ^β ^Ξ± with the slope Ξ± , and known as aΒ poorly constrained but very important function in studies of star and galaxy formation. There are no sensible observational constraints on the IMF slopes beyond the Milky Way and nearby galaxies. Here we combine two sets of observational results, (1) cosmic densities of core-collapse supernova (CCSN) explosion rates and (2) cosmic far-UV radiation (and infrared reradiation) densities, which are sensitive to massive (β8β50 M _β ) and moderately massive (β2.5β7 M _β ) stars, respectively, and constrain the IMF slope at m > 1 M _β with a freedom of redshift evolution. Although no redshift evolution is identified beyond the uncertainties, we find that the cosmic-average IMF slope at z = 0 is Ξ± = 1.8β3.2 at the 95% confidence level that is comparable with the Salpeter IMF, Ξ± = 2.35, which marks the first constraint on the cosmic-average IMF. We show a forecast for the Nancy Grace Roman Space Telescope supernova survey that will provide significantly strong constraints on the IMF slope with Ξ΄ Ξ± β 0.5 over z = 0β2. Moreover, as for an independent IMF probe instead of (1), we suggest to use diffuse supernovae neutrino background (DSNB), relic neutrinos from CCSNe. We expect that the Hyper-Kamiokande neutrino observations over 20 yr will improve the constraints on the IMF slope and the redshift evolution significantly better than those obtained today, if the systematic uncertainties of DSNB production physics are reduced in the future numerical simulations