1,499 research outputs found
Chinese Firmsâ Political Connection, Ownership, and Financing Constraints
We empirically examine some listed Chinese firmsâ political connection, ownership, and financing constraints. Politically-connected firms display no financing constraints whereas firms without connection experience significant constraints. Non-connected family-controlled firms bear greater constraints than non-connected state-owned firms.Political connection; investments; financing constraints; Chinese firms
Financial liberalization and financing constraints: some evidence from panel data of listed Chinese firms
This paper examines the impact of recent financial liberalization in China on the financing constraints and investment of publicly-listed Chinese firms. Two continuous indices are constructed to measure the evolution and intensity of financial reforms: a financial liberalization index and a capital control index. Dynamic panel GMM method is used to estimate firmsâ financing constraints in an Euler-equation investment model. The results indicate that while smaller firms face significant financing constraints than larger firms, financial liberalization has raised the financing constraints for the latter and failed to relieve the constraints for the former. It appears financial reforms in China have subjected larger firms to greater market discipline but the reforms probably have not been profound enough to benefit smaller firms.Financial liberalization; investments; financing constraints; Chinese firms
Neuroprotection and acidosis induced by cortical spreading depression
We read with interest the article âCortical spreading depression produces a neuroprotective effect activating mitochondrial uncoupling protein-5â published in Neuropsychiatr Dis Treat by Viggiano et al.1 The authors showed that cerebral spreading depression (CSD) triggered uncoupling protein-5 (UCP-5),1 which had been reported to exert a long-term effect upon neuron protection.2 The result is another piece in CSD literature on modifying gene expressions to provide neuroprotection to subsequent ischemic episodes.3,
Regional Capital Mobility in China: 1978-2006
We examine cross-region capital mobility in China and track how the degree of mobility has changed over time. The effects of fiscal and redistributive activities of different levels of government in China on private capital mobility are taken into account. Our results indicate that there was a significant improvement in capital mobility over time in China, particularly for private capital in the more developed regions. The central and provincial governments, via their taxation, spending, and transfers, loosen the relationship between private saving and investment and appear to promote capital mobility, particularly for less developed regions. There are considerable differences between more and less developed regions in terms of the degree of capital market integration and the improvement in capital mobility over time. The results have important policy implications on global re-balancing as well as regional development gap and risk-sharing within China.Feldstein-Horioka; Chinese cross-region capital mobility; saving-investment relationship; Chinese capital market integration
Fast Genome-Wide QTL Association Mapping on Pedigree and Population Data
Since most analysis software for genome-wide association studies (GWAS)
currently exploit only unrelated individuals, there is a need for efficient
applications that can handle general pedigree data or mixtures of both
population and pedigree data. Even data sets thought to consist of only
unrelated individuals may include cryptic relationships that can lead to false
positives if not discovered and controlled for. In addition, family designs
possess compelling advantages. They are better equipped to detect rare
variants, control for population stratification, and facilitate the study of
parent-of-origin effects. Pedigrees selected for extreme trait values often
segregate a single gene with strong effect. Finally, many pedigrees are
available as an important legacy from the era of linkage analysis.
Unfortunately, pedigree likelihoods are notoriously hard to compute. In this
paper we re-examine the computational bottlenecks and implement ultra-fast
pedigree-based GWAS analysis. Kinship coefficients can either be based on
explicitly provided pedigrees or automatically estimated from dense markers.
Our strategy (a) works for random sample data, pedigree data, or a mix of both;
(b) entails no loss of power; (c) allows for any number of covariate
adjustments, including correction for population stratification; (d) allows for
testing SNPs under additive, dominant, and recessive models; and (e)
accommodates both univariate and multivariate quantitative traits. On a typical
personal computer (6 CPU cores at 2.67 GHz), analyzing a univariate HDL
(high-density lipoprotein) trait from the San Antonio Family Heart Study
(935,392 SNPs on 1357 individuals in 124 pedigrees) takes less than 2 minutes
and 1.5 GB of memory. Complete multivariate QTL analysis of the three
time-points of the longitudinal HDL multivariate trait takes less than 5
minutes and 1.5 GB of memory
Sex venue-based network analysis to identify HIV prevention dissemination targets for men who have sex with men
Using Growing Self-Organising Maps to Improve the Binning Process in Environmental Whole-Genome Shotgun Sequencing
Metagenomic projects using whole-genome shotgun (WGS)
sequencing produces many unassembled DNA sequences and small
contigs. The step of clustering these sequences, based on
biological and molecular features, is called binning. A
reported strategy for binning that combines oligonucleotide
frequency and self-organising maps (SOM) shows high potential.
We improve this strategy by identifying suitable training
features, implementing a better clustering algorithm, and
defining quantitative measures for assessing results. We
investigated the suitability of each of di-, tri-, tetra-, and
pentanucleotide frequencies. The results show that
dinucleotide frequency is not a sufficiently strong signature
for binning 10 kb long DNA sequences, compared to the other
three. Furthermore, we observed that increased order of
oligonucleotide frequency may deteriorate the assignment
result in some cases, which indicates the possible existence
of optimal species-specific oligonucleotide frequency. We
replaced SOM with growing self-organising map (GSOM) where
comparable results are obtained while gaining
7%â15%
speed improvement
Binning sequences using very sparse labels within a metagenome
<p>Abstract</p> <p>Background</p> <p>In metagenomic studies, a process called binning is necessary to assign contigs that belong to multiple species to their respective phylogenetic groups. Most of the current methods of binning, such as BLAST, <it>k</it>-mer and PhyloPythia, involve assigning sequence fragments by comparing sequence similarity or sequence composition with already-sequenced genomes that are still far from comprehensive. We propose a semi-supervised seeding method for binning that does not depend on knowledge of completed genomes. Instead, it extracts the flanking sequences of highly conserved 16S rRNA from the metagenome and uses them as seeds (labels) to assign other reads based on their compositional similarity.</p> <p>Results</p> <p>The proposed seeding method is implemented on an unsupervised Growing Self-Organising Map (GSOM), and called Seeded GSOM (S-GSOM). We compared it with four well-known semi-supervised learning methods in a preliminary test, separating random-length prokaryotic sequence fragments sampled from the NCBI genome database. We identified the flanking sequences of the highly conserved 16S rRNA as suitable seeds that could be used to group the sequence fragments according to their species. S-GSOM showed superior performance compared to the semi-supervised methods tested. Additionally, S-GSOM may also be used to visually identify some species that do not have seeds.</p> <p>The proposed method was then applied to simulated metagenomic datasets using two different confidence threshold settings and compared with PhyloPythia, <it>k</it>-mer and BLAST. At the reference taxonomic level Order, S-GSOM outperformed all <it>k</it>-mer and BLAST results and showed comparable results with PhyloPythia for each of the corresponding confidence settings, where S-GSOM performed better than PhyloPythia in the ⼠10 reads datasets and comparable in the ⼠8 kb benchmark tests.</p> <p>Conclusion</p> <p>In the task of binning using semi-supervised learning methods, results indicate S-GSOM to be the best of the methods tested. Most importantly, the proposed method does not require knowledge from known genomes and uses only very few labels (one per species is sufficient in most cases), which are extracted from the metagenome itself. These advantages make it a very attractive binning method. S-GSOM outperformed the binning methods that depend on already-sequenced genomes, and compares well to the current most advanced binning method, PhyloPythia.</p
Early post-operative interleukin-6 and tumor necrosis factor-Îą levels after single-port laparoscopic varicocelectomy in children
PURPOSE: Laparoendoscopic single-site surgery has recently been described in children and regarded as an improved technology leading to less pain and better cosmetic outcome. Compared to the traditional three-port method, it is not known if the single-port method is less invasive. The aim of this study was thus to investigate the post-operative acute inflammatory response in order to evaluate surgical stress in the two surgical approaches in children. METHODS: A prospective, single blinded, case-control study was carried out. Thirteen male patients who presented with unilateral varicocele were divided into two groups. Six children underwent single-port laparoscopic procedure, while the other seven children underwent three-port laparoscopic procedure. Pre-operative and post-operative blood samples were taken for the measurement of tumor necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6) using ELISA. Demographics including the operation time, and complications were recorded. Data between the two groups were analyzed using unpaired t-test and a p value of <0.05 was taken as statistically significant. RESULTS: The mean age of patients was 14.5 years (range 12-19 years). There was no significant difference between the two groups in terms of operative time, nor there was any complication recorded. The change in serum TNF-alpha and IL-6 concentrations pre- and post-operatively between the single-port group and three-port group was not statistically significant. Overall, patients in the two groups showed excellent satisfaction in terms of post-operative cosmesis. CONCLUSION: Single-port laparoscopic varicocelectomy is safe, effective and produces excellent cosmesis with minimal surgical stress.published_or_final_versionSpringer Open Choice, 21 Feb 201
Prenatal antidepressant use and risk of attention-deficit/hyperactivity disorder in offspring:population based cohort study
textabstractObjective To assess the potential association between prenatal use of antidepressants and the risk of attention-deficit/hyperactivity disorder (ADHD) in offspring. Design Population based cohort study. Setting Data from the Hong Kong population based electronic medical records on the Clinical Data Analysis and Reporting System. Participants 190 618 children born in Hong Kong public hospitals between January 2001 and December 2009 and followed-up to December 2015. Main outcome measure Hazard ratio of maternal antidepressant use during pregnancy and ADHD in children aged 6 to 14 years, with an average follow-up time of 9.3 years (range 7.4-11.0 years). Results Among 190 618 children, 1252 had a mother who used prenatal antidepressants. 5659 children (3.0%) were given a diagnosis of ADHD or received treatment for ADHD. The crude hazard ratio of maternal antidepressant use during pregnancy was 2.26 (P<0.01) compared with non-use. After adjustment for potential confounding factors, including maternal psychiatric disorders and use of other psychiatric drugs, the adjusted hazard ratio was reduced to 1.39 (95% confidence interval 1.07 to 1.82, P=0.01). Likewise, similar results were observed when comparing children of mothers who had used antidepressants before pregnancy with those who were never users (1.76, 1.36 to 2.30, P<0.01). The risk of ADHD in the children of mothers with psychiatric disorders was higher compared with the children of mothers without psychiatric disorders even if the mothers had never used antidepressants (1.84, 1.54 to 2.18, P<0.01). All sensitivity analyses yielded similar results. Sibling matched analysis identified no significant difference in risk of ADHD in siblings exposed to antidepressants during gestation and those not exposed during gestation (0.54, 0.17 to 1.74, P=0.30). Conclusions The findings suggest that the association between prenatal use of antidepressants and risk of ADHD in offspring can be partially explained by confounding by indication of antidepressants. If there is a causal association, the size of the effect is probably smaller than that reported previously
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