963 research outputs found
Using member galaxy luminosities as halo mass proxies of galaxy groups
Reliable halo mass estimation for a given galaxy system plays an important
role both in cosmology and galaxy formation studies. Here we set out to find
the way that can improve the halo mass estimation for those galaxy systems with
limited brightest member galaxies been observed. Using four mock galaxy samples
constructed from semi-analytical formation models, the subhalo abundance
matching method and the conditional luminosity functions, respectively, we find
that the luminosity gap between the brightest and the subsequent brightest
member galaxies in a halo (group) can be used to significantly reduce the
scatter in the halo mass estimation based on the luminosity of the brightest
galaxy alone. Tests show that these corrections can significantly reduce the
scatter in the halo mass estimations by to in massive
halos depending on which member galaxies are considered. Comparing to the
traditional ranking method, we find that this method works better for groups
with less than five members, or in observations with very bright magnitude cut.Comment: ApJ accepte
Strong-Weak Integrated Semi-supervision for Unsupervised Single and Multi Target Domain Adaptation
Unsupervised domain adaptation (UDA) focuses on transferring knowledge
learned in the labeled source domain to the unlabeled target domain. Despite
significant progress that has been achieved in single-target domain adaptation
for image classification in recent years, the extension from single-target to
multi-target domain adaptation is still a largely unexplored problem area. In
general, unsupervised domain adaptation faces a major challenge when attempting
to learn reliable information from a single unlabeled target domain. Increasing
the number of unlabeled target domains further exacerbate the problem rather
significantly. In this paper, we propose a novel strong-weak integrated
semi-supervision (SWISS) learning strategy for image classification using
unsupervised domain adaptation that works well for both single-target and
multi-target scenarios. Under the proposed SWISS-UDA framework, a strong
representative set with high confidence but low diversity target domain samples
and a weak representative set with low confidence but high diversity target
domain samples are updated constantly during the training process. Both sets
are fused to generate an augmented strong-weak training batch with
pseudo-labels to train the network during every iteration. The extension from
single-target to multi-target domain adaptation is accomplished by exploring
the class-wise distance relationship between domains and replacing the strong
representative set with much stronger samples from peer domains via peer
scaffolding. Moreover, a novel adversarial logit loss is proposed to reduce the
intra-class divergence between source and target domains, which is
back-propagated adversarially with a gradient reverse layer between the
classifier and the rest of the network. Experimental results based on three
benchmarks, Office-31, Office-Home, and DomainNet, show the effectiveness of
the proposed SWISS framework
Constraining the Star Formation Histories in Dark Matter Halos: I. Central Galaxies
Using the self-consistent modeling of the conditional stellar mass functions
across cosmic time by Yang et al. (2012), we make model predictions for the
star formation histories (SFHs) of {\it central} galaxies in halos of different
masses. The model requires the following two key ingredients: (i) mass assembly
histories of central and satellite galaxies, and (ii) local observational
constraints of the star formation rates of central galaxies as function of halo
mass. We obtain a universal fitting formula that describes the (median) SFH of
central galaxies as function of halo mass, galaxy stellar mass and redshift. We
use this model to make predictions for various aspects of the star formation
rates of central galaxies across cosmic time. Our main findings are the
following. (1) The specific star formation rate (SSFR) at high increases
rapidly with increasing redshift [] for halos of a given
mass and only slowly with halo mass () at a given , in
almost perfect agreement with the specific mass accretion rate of dark matter
halos. (2) The ratio between the star formation rate (SFR) in the main-branch
progenitor and the final stellar mass of a galaxy peaks roughly at a constant
value, , independent of halo mass or the
final stellar mass of the galaxy. However, the redshift at which the SFR peaks
increases rapidly with halo mass. (3) More than half of the stars in the
present-day Universe were formed in halos with 10^{11.1}\msunh < M_h <
10^{12.3}\msunh in the redshift range . (4) ... [abridged]Comment: 15 figures, 22 pages, Accepted for publication in Ap
Efficacy of the combination of Tenghuangjiangu tablets, alfacalcidol capsules and caltrate D3 tablets in osteoporotic vertebral compression fracture, and their effects on bone metabolic indices
Purpose: To investigate the efficacy of the combination of Tenghuangjiangu tablets, Alfacalcidol capsules and Caltrate D3 tablets in osteoporotic vertebral compression fracture (OVCF) and their effects on bone metabolic indices.
Methods: Ninety-six patients with OVCF were randomly categorized into study group (SG) and control group (CG). Patients in the CG orally took Caltrate D3 tablets, while those in the SG were given Tenghuangjiangu tablets and Alfacalcidol capsules in addition to caltrate D3 tablets. The Bone mineral density (BMD) values and the treatment efficacy were compared. The levels of bone metabolism markers (PINP, β-CTX, BGP, NBAP), CT and PTH were determined using electrochemiluminescence immunoassay, while Ca2+ levels were assessed using liquid level detection. The incidence of adverse reactions (re-fracture, gastrointestinal reaction, hypotension and abnormal coagulation function) were compared.
Results: Treatment efficacy in the SG was 91.67 %, which was significantly higher than that in the CG (81.25 %; p < 0.05). Before treatment, the two groups showed no significant differences in BMD, PINP, β-CTX, BGP, NBAP, Ca2+, CT, and PTH levels (p > 0.05). After treatment, the SG exhibited significantly higher BMD, PINP, BGP, NBAP, Ca2+ and CT levels, and showed lower β-CTX and PTH levels than the CG (p < 0.05). The SG exhibited a significantly lower incidence rate of adverse reactions than that the CG (p < 0.05).
Conclusion: The combination of Tenghuangjiangu tablets, Alfacalcidol capsules, and Caltrate D3 tablets, improves bone metabolic indices, bone density and treatment efficacy while reducing the incidence rate of adverse reactions
The Incomplete Conditional Stellar Mass Function: Unveiling the Stellar Mass Functions of Galaxies at 0.1 < Z < 0.8 from BOSS Observations
We propose a novel method to constrain the missing fraction of galaxies using
galaxy clustering measurements in the galaxy conditional stellar mass function
(CSMF) framework, which is applicable to surveys that suffer significantly from
sample selection effects. The clustering measurements, which are not sensitive
to the random sampling (missing fraction) of galaxies, are widely used to
constrain the stellar-halo mass relation (SHMR). By incorporating a missing
fraction (incompleteness) component into the CSMF model (ICSMF), we use the
incomplete stellar mass function and galaxy clustering to simultaneously
constrain the missing fractions and the SHMRs. Tests based on mock galaxy
catalogs with a few typical missing fraction models show that this method can
accurately recover the missing fraction and the galaxy SHMR, and hence provides
us reliable measurements of the galaxy stellar mass functions. We then apply it
to the Baryon Oscillation Spectroscopic Survey (BOSS) over the redshift range
of 0.110^{11}M_\odot10^{11}M_\odot<M_*<10^{12}M_\odot$, as well as the SHMRs, over the redshift
range 0.1<z<0.8 in this largest galaxy redshift survey.Comment: 18 pages, 12 figures. Accepted for publication in Ap
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