SNP heritability, the proportion of phenotypic variance explained by SNPs, has been reported for many hundreds of traits. Its estimation requires strong prior assumptions about the distribution of ...heritability across the genome, but current assumptions have not been thoroughly tested. By analyzing imputed data for a large number of human traits, we empirically derive a model that more accurately describes how heritability varies with minor allele frequency (MAF), linkage disequilibrium (LD) and genotype certainty. Across 19 traits, our improved model leads to estimates of common SNP heritability on average 43% (s.d. 3%) higher than those obtained from the widely used software GCTA and 25% (s.d. 2%) higher than those from the recently proposed extension GCTA-LDMS. Previously, DNase I hypersensitivity sites were reported to explain 79% of SNP heritability; using our improved heritability model, their estimated contribution is only 24%.
We present new calibrations of far-ultraviolet (FUV) attenuation as derived from the total infrared to FUV luminosity ratio (IRX) and the FUV-near-UV(NUV) color. We find that the IRX-corrected FUV ...luminosities are tightly and linearly correlated with the attenuation-corrected H Delta *a luminosities (as measured from the Balmer decrement), with an rms scatter of ?0.09 dex. The ratios of these attenuation-corrected FUV to H Delta *a luminosities are consistent with evolutionary synthesis model predictions, assuming a constant star formation rate over 100 Myr, solar metallicity, and either a Salpeter or a Kroupa initial mass function with lower and upper mass limits of 0.1 and 100 M . The IRX-corrected FUV to Balmer-corrected H Delta *a luminosity ratios do not show any trend with other galactic properties over the ranges covered by our sample objects. In contrast, FUV attenuation derived from the FUV-NUV color (UV spectral slope) show much larger random and systematic uncertainties. When compared to either Balmer-corrected H Delta *a luminosities or IRX-corrected FUV luminosities the color-corrected FUV luminosities show ~2.5 times larger rms scatter, and systematic nonlinear deviations as functions of luminosity and other parameters. Linear combinations of 25 Delta *mm and 1.4 GHz radio continuum luminosities with the observed FUV luminosities are also well correlated with the Balmer-corrected H Delta *a luminosities. These results provide useful prescriptions for deriving attenuation-corrected star formation rates of galaxies based on linear combinations of UV and IR or radio luminosities, which are presented in convenient tabular form. Comparisons of our calibrations with attenuation corrections in the literature and with dust attenuation laws are also made.
Abstract
We investigate the star formation histories (SFHs) of massive red spiral galaxies with stellar mass
M
*
> 10
10.5
M
⊙
, and make comparisons with blue spirals and red ellipticals of similar ...masses. We make use of the integral field spectroscopy from the Sloan Digital Sky Survey IV/DR15 MaNGA sample, and estimate spatially resolved SFHs and stellar population properties of each galaxy by applying a Bayesian spectral fitting code to the MaNGA spectra. We find that both red spirals and red ellipticals have experienced only one major star formation episode at early times, and the result is independent of the adopted SFH model. On average, more than half of their stellar masses were formed >10 Gyr ago, and more than 90% were formed >6 Gyr ago. The two types of galaxies show similarly flat profiles in a variety of stellar population parameters: old stellar ages indicated by
D
4000 (the spectral break at around 4000 Å), high stellar metallicities, large Mgb/Fe ratios indicating fast formation, and little stellar dust attenuation. In contrast, although blue spirals also formed their central regions >10 Gyr ago, both their central regions and outer disks continuously form stars over a long timescale. Our results imply that massive red spirals are likely to share some common processes of formation (and possibly quenching) with massive red ellipticals in the sense that both types were formed at
z
> 2 through a fast formation process. Possible mechanisms for the formation and quenching of massive red spirals are discussed.
To understand the formation and quenching processes of local massive red spiral galaxies with M* > 1010.5 M , we perform a statistical analysis of their spectroscopic and structural properties and ...compare them with elliptical and blue spiral galaxies of similar mass. The sample was selected from the stellar mass catalog of galaxies in SDSS DR7, according to their locations on the u − r color−stellar mass diagram. We find that red spirals harbor compact cores with high stellar mass surface densities measured by 1 and are bulge dominated. Particularly, the red spirals, especially their bulges, follow the 1-M* ridgeline for quenched galaxies. Furthermore, the red spirals show similarly large central Dn(4000), high Mg/Fe, and dark matter halo mass to ellipticals. These results suggest that the bulges of red spirals formed within a short timescale before redshift ∼1-2 and were quenched via a fast mode, similar to ellipticals. Careful examinations of the optical morphologies reveal that ∼70% of red spirals show strong bars, rings/shells, and even merging features, which suggests that interactions or mergers might have played an important role in the formation of red spirals. In contrast, most of the massive blue spirals have completely different spectral and structural properties from red spirals. However, the blue spirals with high 1 ( ) show similar structural and morphological properties, as well as similar halo mass and H i mass to red spirals. We discuss rejuvenation from red to blue as a possible explanation for these high- 1 blue spirals.
Berberine (BBR), a small alkaloid, is used as a hypoglycemic agent in China. Stachyose (Sta), a Rehmannia glutinosa oligosaccharide, acts as a prebiotic. This study aimed to evaluate whether BBR ...combined with Sta produced better glycometabolism than BBR alone, and explored the effects on gut microbiota and metabolomics. Type‐2 diabetic db/db mice were administered BBR (100 mg/kg), Sta (200 mg/kg), or both by gavage once daily. Glucose metabolism, the balance of α‐ and β‐cells, and mucin‐2 expression were ameliorated by combined treatment of BBR and Sta, with stronger effects than upon treatment with BBR alone. The microbial diversity and richness were altered after combined treatment and after treatment with BBR alone. The abundance of Akkermansia muciniphila was increased by combined treatment compared to treatment with BBR alone, while the levels of the metabolite all‐trans‐heptaprenyl diphosphate were decreased and the levels of fumaric acid were increased, which both showed a strong correlation with A. muciniphila. In summary, BBR combined with Sta produced better glycometabolism than BBR alone through modulating gut microbiota and fecal metabolomics, and may aid in the development of a novel pharmaceutical strategy for treating Type 2 diabetes mellitus.
Abstract
Ly
α
emitters (LAEs) may represent an important galaxy population in the low-mass regime. We present our deep narrowband imaging surveys in the COSMOS and ECDF-S fields and study the ...properties of LAEs at
z
= 2.23 ± 0.03. The narrowband surveys conducted at the Magellan II telescope allow us to obtain a sample of 452 LAEs, reaching a 5
σ
limiting magnitude of ∼26 mag. Our Ly
α
luminosity functions extend to L(Ly
α
) =10
41.8
erg s
−1
with a steep faint-end slope. Using multiwavelength ancillary data, especially the deep
Spitzer
/IRAC 3.6 and 4.5
μ
m photometric data, we obtained reliable stellar mass estimates for 130 IRAC-detected LAEs, spanning a range of 8 < log(
M
⋆
/
M
⊙
) < 11.5. For the remaining IRAC-undetected LAEs, the median-stacked spectral energy distribution yields a stellar mass of
and the rest-frame ultraviolet emission indicates a median star formation rate (SFR) of log (SFR/
M
⊙
yr
−1
) = −0.14 ± 0.35. There are six LAEs detected by the
Spitzer
/MIPS 24
μ
m or even
Herschel
far-infrared observations. Taking into account the six mid-IR/far-IR-detected LAEs, our LAEs cover a wide range in the SFR (1
M
⊙
yr
−1
< SFR < 2000
M
⊙
yr
−1
). Although LAEs as a population are diverse in their stellar properties, they are mostly low-mass star-forming galaxies and follow the star formation main-sequence relations or their extrapolations to the low-mass end, implying a normal star-forming nature of LAEs. The clustering analysis indicates that our LAEs reside in dark matter halos with
, suggesting that they are progenitors of local LMC-like galaxies.
Background
Preoperative diagnosis of liver fibrosis in children with pancreaticobiliary maljunction (PBM) is needed to guide clinical decision‐making and improve patient prognosis.
Purpose
To develop ...and validate an MR‐based radiomics‐clinical nomogram for identifying liver fibrosis in children with PBM.
Study Type
Retrospective.
Population
A total of 136 patients with PBM from two centers (center A: 111 patients; center B: 25 patients). Cases from center A were randomly divided into training (74 patients) and internal validation (37 patients) sets. Cases from center B were assigned to the external validation set. Liver fibrosis was determined by histopathological examination.
Field Strength/Sequence
A 3.0 T (two vendors)/T1‐weighted imaging and T2‐weighted imaging.
Assessment
Clinical factors associated with liver fibrosis were evaluated. A total of 3562 radiomics features were extracted from segmented liver parenchyma. Maximum relevance minimum redundancy and least absolute shrinkage and selection operator were recruited to screen radiomics features. Based on the selected variables, multivariate logistic regression was used to construct the clinical model, radiomics model, and combined model. The combined model was visualized as a nomogram to show the impact of the radiomics signature and key clinical factors on the individual risk of developing liver fibrosis.
Statistical Tests
Mann–Whitney U and chi‐squared tests were used to compare clinical factors. P < 0.05 was considered statistically significant in the final models.
Results
Two clinical factors and four radiomics features were selected as they were associated with liver fibrosis in the training (AUC, 0.723, 0.927), internal validation (AUC, 0.718, 0.885), and external validation (AUC, 0.737, 0.865) sets. The radiomics‐clinical nomogram yielded the best performance in the training (AUC, 0.977), internal validation (AUC, 0.921), and external validation (AUC, 0.878) sets, with good calibration (P > 0.05).
Data Conclusion
Our radiomic‐based nomogram is a noninvasive, accurate, and preoperative diagnostic tool that is able to detect liver fibrosis in PBM children.
Evidence Level
3.
Technical Efficacy
Stage 2.
We studied the magnetization evolution in three-dimensional chiral nanostructures, including nanotubes and circularly curved thin films, by micromagnetic simulations. We found that in a nanotube ...skyrmions can be formed by broken of the helical stripes on the left and right sides of the nanotube, and the formation of skyrmions doesn't correspond to any abrupt change of topological number. Skyrmions can exist in a large range of magnetic field, and the thinner nanotube has a larger field range for skyrmion existence. The configuration of a skyrmion in nanotubes is different from the one in thin film. From the outer to the inner circular layer, the size of the skyrmion becomes larger, and the deformation becomes more obvious. In circularly curved magnetic films with fixed arc length, there are three kinds of hysteresis processes are found. For the curved films with a large radius, the magnetization evolution behavior is similar to the case in two-dimensional thin films. For the curved films with a small radius, the skyrmions are created by broken of the helical stripes on the left and right sides of the curved film. For the curved film with a medium radius, no skyrmion is formed in the hysteresis process.
A simple and efficient electrochemical selenylation of uracils in the presence of NH4I for the synthesis of 5‐selenouracils has been developed. This transformation was performed in the transition ...metal‐free, oxidant‐free, and aerobic conditions, providing a rapid and practical protocol to 5‐selenouracil derivatives.
A simple and efficient electrochemical selenylation of uracils in the presence of NH4I for the synthesis of 5‐selenouracils has been developed. This transformation was performed in the transition metal‐free, oxidant‐free, and air conditions, providing a rapid and practical protocol to 5‐selenouracil derivatives.
Abstract
Based on independent shear measurements using the Dark Energy Camera Legacy Survey/DR8 imaging data, we measure the weak lensing signals around isolated central galaxies (ICGs) from Sloan ...Digital Sky Survey/DR7 at
z
∼ 0.1. The projected stellar mass density profiles of satellite galaxies are further deduced, using photometric sources from the Hyper Suprime-cam survey. The signals of ICGs + their extended stellar halos are taken from Wang et al. All measurements are compared with predictions by the IllustrisTNG300-1 simulation. We find, overall, a good agreement between observation and TNG300. In particular, a correction to the stellar mass of massive observed ICGs is applied based on the calibration of He et al., which brings a much better agreement with TNG300 predicted lensing signals at
log
10
M
*
/
M
⊙
>
11.1
. In real observation, red ICGs are hosted by more massive dark matter halos and have more satellites and more extended stellar halos than blue ICGs at fixed stellar mass. However, in TNG300 there are more satellites around blue ICGs at fixed stellar mass, and the outer stellar halos of red and blue ICGs are similar. The stellar halos of TNG galaxies are more extended compared with real observed galaxies, especially for blue ICGs with
log
10
M
*
/
M
⊙
>
10.8
. We find the same trend for TNG100 galaxies and for true halo central galaxies. The tensions between TNG and real galaxies indicate that satellite disruptions are stronger in TNG. In both TNG300 and observation, satellites approximately trace the underlying dark matter distribution beyond 0.1
R
200
, but the fraction of total stellar mass in TNG300 does not show the same radial distribution as real galaxies.
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