2,384 research outputs found
The Methods to Improve Quality of Service by Accounting Secure Parameters
A solution to the problem of ensuring quality of service, providing a greater
number of services with higher efficiency taking into account network security
is proposed. In this paper, experiments were conducted to analyze the effect of
self-similarity and attacks on the quality of service parameters. Method of
buffering and control of channel capacity and calculating of routing cost
method in the network, which take into account the parameters of traffic
multifractality and the probability of detecting attacks in telecommunications
networks were proposed. The both proposed methods accounting the given
restrictions on the delay time and the number of lost packets for every type
quality of service traffic. During simulation the parameters of transmitted
traffic (self-similarity, intensity) and the parameters of network (current
channel load, node buffer size) were changed and the maximum allowable load of
network was determined. The results of analysis show that occurrence of
overload when transmitting traffic over a switched channel associated with
multifractal traffic characteristics and presence of attack. It was shown that
proposed methods can reduce the lost data and improve the efficiency of network
resources.Comment: 10 pages, 1 figure, 1 equation, 1 table. arXiv admin note: text
overlap with arXiv:1904.0520
The influence of long-term treadmill exercise on bone mass and articular cartilage in ovariectomized rats
<p>Abstract</p> <p>Background</p> <p>Loss of bone quality and deterioration of articular cartilage are commonly seen after menopause. While exercise may protect against tissue degeneration, a clear link has yet to be established. The aim of the present study is to investigate the influence of long-term treadmill exercise on changes in bone mass and articular cartilage in ovariectomized rats.</p> <p>Methods</p> <p>Sixty female Sprague-Dawley rats were randomly assigned to 4 groups: ovariectomized (OVX), ovariectomized plus treadmill exercise (OVX-RUN), treadmill exercise alone (RUN), and control (CON) groups. After 36 weeks, the following variables were compared among the 4 groups. Bone mass was evaluated by trabecular bone volume and bone mineral density (BMD). Articular cartilage in the knee joints was evaluated by histology analysis and a modified Mankin score.</p> <p>Results</p> <p>Rats in the ovariectomized groups (OVX and OVX-RUN) had significantly lower BMD and bone mass than the non-ovariectomized rats (CON and RUN), indicating that exercise did little to preserve bone mass. However, the sedentary OVX group had a significantly worse modified Mankin score (7.7 ± 1.4) than the OVX-RUN group (4.8 ± 1.0), whose scores did not differ significantly from the other 2 non-operated groups. The articular cartilage in the sedentary OVX rats was relatively thinner, hypocellular, and had more clefts than in the other 3 groups.</p> <p>Conclusion</p> <p>This study suggests that long-term exercise protects articular cartilage in OVX rats but does not retard the loss of bone mass seen in after menopause.</p
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al
Hierarchical Generalized Linear Models for Multiple Groups of Rare and Common Variants: Jointly Estimating Group and Individual-Variant Effects
Complex diseases and traits are likely influenced by many common and rare genetic variants and environmental factors. Detecting disease susceptibility variants is a challenging task, especially when their frequencies are low and/or their effects are small or moderate. We propose here a comprehensive hierarchical generalized linear model framework for simultaneously analyzing multiple groups of rare and common variants and relevant covariates. The proposed hierarchical generalized linear models introduce a group effect and a genetic score (i.e., a linear combination of main-effect predictors for genetic variants) for each group of variants, and jointly they estimate the group effects and the weights of the genetic scores. This framework includes various previous methods as special cases, and it can effectively deal with both risk and protective variants in a group and can simultaneously estimate the cumulative contribution of multiple variants and their relative importance. Our computational strategy is based on extending the standard procedure for fitting generalized linear models in the statistical software R to the proposed hierarchical models, leading to the development of stable and flexible tools. The methods are illustrated with sequence data in gene ANGPTL4 from the Dallas Heart Study. The performance of the proposed procedures is further assessed via simulation studies. The methods are implemented in a freely available R package BhGLM (http://www.ssg.uab.edu/bhglm/)
The gray matter volume of the amygdala is correlated with the perception of melodic intervals: a voxel-based morphometry study
Music is not simply a series of organized pitches, rhythms, and timbres, it is capable of evoking emotions. In the present study, voxel-based morphometry (VBM) was employed to explore the neural basis that may link music to emotion. To do this, we identified the neuroanatomical correlates of the ability to extract pitch interval size in a music segment (i.e., interval perception) in a large population of healthy young adults (N = 264). Behaviorally, we found that interval perception was correlated with daily emotional experiences, indicating the intrinsic link between music and emotion. Neurally, and as expected, we found that interval perception was positively correlated with the gray matter volume (GMV) of the bilateral temporal cortex. More important, a larger GMV of the bilateral amygdala was associated with better interval perception, suggesting that the amygdala, which is the neural substrate of emotional processing, is also involved in music processing. In sum, our study provides one of first neuroanatomical evidence on the association between the amygdala and music, which contributes to our understanding of exactly how music evokes emotional responses
Bayesian shrinkage mapping of quantitative trait loci in variance component models
<p>Abstract</p> <p>Background</p> <p>In this article, I propose a model-selection-free method to map multiple quantitative trait loci (QTL) in variance component model, which is useful in outbred populations. The new method can estimate the variance of zero-effect QTL infinitely to zero, but nearly unbiased for non-zero-effect QTL. It is analogous to Xu's Bayesian shrinkage estimation method, but his method is based on allelic substitution model, while the new method is based on the variance component models.</p> <p>Results</p> <p>Extensive simulation experiments were conducted to investigate the performance of the proposed method. The results showed that the proposed method was efficient in mapping multiple QTL simultaneously, and moreover it was more competitive than the reversible jump MCMC (RJMCMC) method and may even out-perform it.</p> <p>Conclusions</p> <p>The newly developed Bayesian shrinkage method is very efficient and powerful for mapping multiple QTL in outbred populations.</p
Interplay between NS3 protease and human La protein regulates translation-replication switch of Hepatitis C virus
HCV NS3 protein plays a central role in viral polyprotein processing and RNA replication. We demonstrate that the NS3 protease (NS3pro) domain alone can specifically bind to HCV-IRES RNA, predominantly in the SLIV region. The cleavage activity of the NS3 protease domain is reduced upon HCV-RNA binding. More importantly, NS3pro binding to the SLIV hinders the interaction of La protein, a cellular IRES-trans acting factor required for HCV IRES-mediated translation, resulting in inhibition of HCV-IRES activity. Although overexpression of both NS3pro as well as the full length NS3 protein decreased the level of HCV IRES mediated translation, replication of HCV replicon RNA was enhanced significantly. These observations suggest that the NS3pro binding to HCV IRES reduces translation in favor of RNA replication. The competition between the host factor (La) and the viral protein (NS3) for binding to HCV IRES might regulate the molecular switch from translation to replication of HCV
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