725 research outputs found
THE INFLUENCE OF BACKPACK CARRIAGE ON TRUNK POSTURE IN CHILDREN DURING UNPLANNED GAIT TERMINATION
This study aimed to examine the trunk posture in children with different backpack loads during unplanned gait termination. Twelve school boys aged 9–10 years completed unplanned and planned gait termination with a backpack load of 0%, 10%, and 15% of their body weight (BW) while level walking. Trunk inclination angle and trunk range of motion at sagittal plane and spinal angle at frontal plane were examined. In comparison
with 0% BW load condition, the spinal angle increased significantly at 10% and 15% BW load condition during gait termination (
ELUCID - Exploring the Local Universe with reConstructed Initial Density field III: Constrained Simulation in the SDSS Volume
A method we developed recently for the reconstruction of the initial density
field in the nearby Universe is applied to the Sloan Digital Sky Survey Data
Release 7. A high-resolution N-body constrained simulation (CS) of the
reconstructed initial condition, with particles evolved in a 500 Mpc/h
box, is carried out and analyzed in terms of the statistical properties of the
final density field and its relation with the distribution of SDSS galaxies. We
find that the statistical properties of the cosmic web and the halo populations
are accurately reproduced in the CS. The galaxy density field is strongly
correlated with the CS density field, with a bias that depend on both galaxy
luminosity and color. Our further investigations show that the CS provides
robust quantities describing the environments within which the observed
galaxies and galaxy systems reside. Cosmic variance is greatly reduced in the
CS so that the statistical uncertainties can be controlled effectively even for
samples of small volumes.Comment: submitted to ApJ, 19 pages, 22 figures. Please download the
high-resolution version at http://staff.ustc.edu.cn/~whywang/paper
A new quantum group associated with a ‘nonstandard’ braid group representation
A new quantum group is derived from a ‘nonstandard’ braid group representation by employing the Faddeev-Reshetikhin-Takhtajan constructive method. The classical limit is not a Lie superalgebra, despite relations like x 2 − y 2 =0. We classify all finite-dimensional irreducible representations of the new Hopf algebra and find only one- and two-dimensional ones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43208/1/11005_2004_Article_BF00420369.pd
ELUCID IV: Galaxy Quenching and its Relation to Halo Mass, Environment, and Assembly Bias
We examine the quenched fraction of central and satellite galaxies as a
function of galaxy stellar mass, halo mass, and the matter density of their
large scale environment. Matter densities are inferred from our ELUCID
simulation, a constrained simulation of local Universe sampled by SDSS, while
halo masses and central/satellite classification are taken from the galaxy
group catalog of Yang et al. The quenched fraction for the total population
increases systematically with the three quantities. We find that the
`environmental quenching efficiency', which quantifies the quenched fraction as
function of halo mass, is independent of stellar mass. And this independence is
the origin of the stellar mass-independence of density-based quenching
efficiency, found in previous studies. Considering centrals and satellites
separately, we find that the two populations follow similar correlations of
quenching efficiency with halo mass and stellar mass, suggesting that they have
experienced similar quenching processes in their host halo. We demonstrate that
satellite quenching alone cannot account for the environmental quenching
efficiency of the total galaxy population and the difference between the two
populations found previously mainly arises from the fact that centrals and
satellites of the same stellar mass reside, on average, in halos of different
mass. After removing these halo-mass and stellar-mass effects, there remains a
weak, but significant, residual dependence on environmental density, which is
eliminated when halo assembly bias is taken into account. Our results therefore
indicate that halo mass is the prime environmental parameter that regulates the
quenching of both centrals and satellites.Comment: 21 pages, 16 figures, submitted to Ap
ELUCID V. Lighting dark matter halos with galaxies
In a recent study, using the distribution of galaxies in the north galactic
pole of SDSS DR7 region enclosed in a 500\mpch box, we carried out our ELUCID
simulation (Wang et al. 2016, ELUCID III). Here we {\it light} the dark matter
halos and subhalos in the reconstructed region in the simulation with galaxies
in the SDSS observations using a novel {\it neighborhood} abundance matching
method. Before we make use of thus established galaxy-subhalo connections in
the ELUCID simulation to evaluate galaxy formation models, we set out to
explore the reliability of such a link. For this purpose, we focus on the
following a few aspects of galaxies: (1) the central-subhalo luminosity and
mass relations; (2) the satellite fraction of galaxies; (3) the conditional
luminosity function (CLF) and conditional stellar mass function (CSMF) of
galaxies; and (4) the cross correlation functions between galaxies and the dark
matter particles, most of which are measured separately for all, red and blue
galaxy populations. We find that our neighborhood abundance matching method
accurately reproduces the central-subhalo relations, satellite fraction, the
CLFs and CSMFs and the biases of galaxies. These features ensure that thus
established galaxy-subhalo connections will be very useful in constraining
galaxy formation processes. And we provide some suggestions on the three levels
of using the galaxy-subhalo pairs for galaxy formation constraints. The
galaxy-subhalo links and the subhalo merger trees in the SDSS DR7 region
extracted from our ELUCID simulation are available upon request.Comment: 18 pages, 13 figures, ApJ accepte
A prediction model for short-term neurodevelopmental impairment in preterm infants with gestational age less than 32 weeks
IntroductionEarly identification and intervention of neurodevelopmental impairment in preterm infants may significantly improve their outcomes. This study aimed to build a prediction model for short-term neurodevelopmental impairment in preterm infants using machine learning method.MethodsPreterm infants with gestational age  < 32 weeks who were hospitalized in The Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, and were followed-up to 18 months corrected age were included to build the prediction model. The training set and test set are divided according to 8:2 randomly by Microsoft Excel. We firstly established a logistic regression model to screen out the indicators that have a significant effect on predicting neurodevelopmental impairment. The normalized weights of each indicator were obtained by building a Support Vector Machine, in order to measure the importance of each predictor, then the dimension of the indicators was further reduced by principal component analysis methods. Both discrimination and calibration were assessed with a bootstrap of 505 resamples.ResultsIn total, 387 eligible cases were collected, 78 were randomly selected for external validation. Multivariate logistic regression demonstrated that gestational age(p = 0.0004), extrauterine growth restriction (p = 0.0367), vaginal delivery (p = 0.0009), and hyperbilirubinemia (0.0015) were more important to predict the occurrence of neurodevelopmental impairment in preterm infants. The Support Vector Machine had an area under the curve of 0.9800 on the training set. The results of the model were exported based on 10-fold cross-validation. In addition, the area under the curve on the test set is 0.70. The external validation proves the reliability of the prediction model.ConclusionA support vector machine based on perinatal factors was developed to predict the occurrence of neurodevelopmental impairment in preterm infants with gestational age  < 32 weeks. The prediction model provides clinicians with an accurate and effective tool for the prevention and early intervention of neurodevelopmental impairment in this population
Characteristics and outcomes for patients with advanced vaginal or vulvar cancer referred to a phase I clinical trials program: the MD Anderson cancer center experience
Expression of three essential antioxidants of Helicobacter pylori in clinical isolates
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