40 research outputs found
Quenching parameter in a holographic thermal QCD
We have calculated the quenching parameter, in a model-independent
way using the gauge-gravity duality. In earlier calculations, the geometry in
the gravity side at finite temperature was usually taken as the pure AdS
blackhole metric for which the dual gauge theory becomes conformally invariant
unlike QCD. Therefore we use a metric which incorporates the fundamental quarks
by embedding the coincident D7 branes in the Klebanov-Tseytlin background and a
finite temperature is switched on by inserting a black hole into the
background, known as OKS-BH metric. Further inclusion of an additional UV cap
to the metric prepares the dual gauge theory to run similar to thermal QCD.
Moreover is usually defined in the literature from the Glauber-model
perturbative QCD evaluation of the Wilson loop, which has no reasons to hold if
the coupling is large and is thus against the main idea of gauge-gravity
duality. Thus we use an appropriate definition of : , where is the separation for which the Wilson loop is equal to some
specific value. The above two refinements cause to vary with the
temperature as always and to depend linearly on the light-cone time
with an additional () correction term in the short-distance limit
whereas in the long-distance limit, it depends only linearly on with no
correction term. These observations agree with other holographic calculations
directly or indirectly.Comment: 16 page
Covariance matrices for the Lyman- forest using the lognormal approximation
We investigate the nature of correlations in the small-scale flux statistics
of the Lyman- (Ly) forest across redshift bins. Understanding
these correlations is important for unbiased cosmological and astrophysical
parameter inference using the Ly forest. We focus on the 1-dimensional
flux power spectrum (FPS) and mean flux () simulated using the
semi-numerical lognormal model we developed in earlier work. The lognormal
model can capture the effects of long wavelength modes with relative ease as
compared to full smoothed particle hydrodynamical (SPH) simulations that are
limited by box volume. For a single redshift bin of size ,
we show that the lognormal model predicts positive cross-correlations between
-bins in the FPS, and a negative correlation for FPS, in
qualitative agreement with SPH simulations and theoretical expectations. For
measurements across two neighbouring redshift bins of width each
(obtained by 'splitting' skewers of length in half), the lognormal
model predicts an anti-correlation for FPS FPS and a positive
correlation for FPS, caused by long wavelength modes. This is in
contrast to SPH simulations which predict a negligible magnitude for
cross-redshift correlations derived from such `split' skewers, and we discuss
possible reasons for this difference. Finally, we perform a preliminary test of
the impact of neglecting long wavelength modes on parameter inference, finding
that whereas the correlation structure of neighbouring redshift bins has
relatively little impact, the absence of long wavelength modes in the model can
lead to biases in the inference of astrophysical parameters.
Our results motivate a more careful treatment of long wavelength modes in
analyses that rely on the small scale Ly forest for parameter
inference.Comment: 17 pages, 6 figures, to be submitted to JCA
A modified lognormal approximation of the Lyman- forest: comparison with full hydrodynamic simulations at
Observations of the Lyman- forest in distant quasar spectra with
upcoming surveys are expected to provide significantly larger and
higher-quality datasets. To interpret these datasets, it is imperative to
develop efficient simulations. One such approach is based on the assumption
that baryonic densities in the intergalactic medium (IGM) follow a lognormal
distribution. We extend our earlier work to assess the robustness of the
lognormal model of the Lyman- forest in recovering the parameters
characterizing IGM state, namely, the mean-density IGM temperature (), the
slope of the temperature-density relation (), and the hydrogen
photoionization rate (), by comparing with high-resolution
Sherwood SPH simulations across the redshift range . These
parameters are estimated through a Markov Chain Monte Carlo technique, using
the mean and power spectrum of the transmitted flux. We find that the usual
lognormal distribution of IGM densities cannot recover the parameters of the
SPH simulations. This limitation arises from the fact that the SPH baryonic
density distribution cannot be described by a simple lognormal form. To address
this, we extend the model by scaling the linear density contrast by a parameter
. While the resulting baryonic density is still lognormal, the additional
parameter gives us extra freedom in setting the variance of density
fluctuations. With this extension, values of and implied in the
SPH simulations are recovered at ( 10%) of the median
(best-fit) values for most redshifts bins. However, this extended lognormal
model cannot recover reliably, with the best-fit value discrepant
by for . Despite this limitation in the recovery of
, we argue that the model remains useful for constraining
cosmological parameters.Comment: 17 pages, 8 figure
Repetitive task training for improving functional ability after stroke
Background
Repetitive task training (RTT) involves the active practice of task-specific motor activities and is a component of current therapy approaches in stroke rehabilitation.
Objectives
Primary objective: To determine if RTT improves upper limb function/reach and lower limb function/balance in adults after stroke.
Secondary objectives: 1) To determine the effect of RTT on secondary outcome measures including activities of daily living, global motor function, quality of life/health status and adverse events. 2) To determine the factors that could influence primary and secondary outcome measures, including the effect of 'dose' of task practice; type of task (whole therapy, mixed or single task); timing of the intervention and type of intervention.
Search methods
We searched the Cochrane Stroke Group Trials Register (4 March 2016); the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 5: 1 October 2006 to 24 June 2016); MEDLINE (1 October 2006 to 8 March 2016); Embase (1 October 2006 to 8 March 2016); CINAHL (2006 to 23 June 2016); AMED (2006 to 21 June 2016) and SPORTSDiscus (2006 to 21 June 2016).
Selection criteria
Randomised/quasi-randomised trials in adults after stroke, where the intervention was an active motor sequence performed repetitively within a single training session, aimed towards a clear functional goal.
Data collection and analysis
Two review authors independently screened abstracts, extracted data and appraised trials. We determined the quality of evidence within each study and outcome group using the Cochrane 'Risk of bias' tool and GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria. We did not assess follow-up outcome data using GRADE. We contacted trial authors for additional information.
Main results
We included 33 trials with 36 intervention-control pairs and 1853 participants. The risk of bias present in many studies was unclear due to poor reporting; the evidence has therefore been rated 'moderate' or 'low' when using the GRADE system.
There is low-quality evidence that RTT improves arm function (standardised mean difference (SMD) 0.25, 95% confidence interval (CI) 0.01 to 0.49; 11 studies, number of participants analysed = 749), hand function (SMD 0.25, 95% CI 0.00 to 0.51; eight studies, number of participants analysed = 619), and lower limb functional measures (SMD 0.29, 95% CI 0.10 to 0.48; five trials, number of participants analysed = 419).
There is moderate-quality evidence that RTT improves walking distance (mean difference (MD) 34.80, 95% CI 18.19 to 51.41; nine studies, number of participants analysed = 610) and functional ambulation (SMD 0.35, 95% CI 0.04 to 0.66; eight studies, number of participants analysed = 525). We found significant differences between groups for both upper-limb (SMD 0.92, 95% CI 0.58 to 1.26; three studies, number of participants analysed = 153) and lower-limb (SMD 0.34, 95% CI 0.16 to 0.52; eight studies, number of participants analysed = 471) outcomes up to six months post treatment but not after six months. Effects were not modified by intervention type, dosage of task practice or time since stroke for upper or lower limb. There was insufficient evidence to be certain about the risk of adverse events.
Authors' conclusions
There is low- to moderate-quality evidence that RTT improves upper and lower limb function; improvements were sustained up to six months post treatment. Further research should focus on the type and amount of training, including ways of measuring the number of repetitions actually performed by participants. The definition of RTT will need revisiting prior to further updates of this review in order to ensure it remains clinically meaningful and distinguishable from other interventions
Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
G-quadruplexes in MTOR and induction of autophagy
Abstract G-quadruplex (G4) structures have emerged as singular therapeutic targets for cancer and neurodegeneration. Autophagy, a crucial homeostatic mechanism of the cell, is often dysregulated in neurodegenerative diseases and cancers. We used QGRS mapper to identify 470 G4 sequences in MTOR, a key negative regulator of autophagy. We sought to identify a functional context by leveraging the effect of G4-targeting ligands on MTOR G4 sequences. The effect of Bis-4,3, a G4 selective dimeric carbocyanine dye, was compared with the known G4-stabilizing activity of the porphyrin, TMPyP4 in HeLa and SHSY-5Y cells. Our results show that treatment with G4-selective ligands downregulates MTOR RNA and mTOR protein expression levels. This is the first report describing G4 motifs in MTOR. This study indicates a possible role of G4 stabilizing ligands in induction of autophagy by downregulation of mTOR levels, albeit not precluding MTOR independent pathways
Biogeochemical networks in the abandoned historical gold mines affecting mobilization and transport of arsenic in Kolar
Enormous water-logging in ancient abandoned mining shafts of Kolar Gold Fields (KGFs), has largely induced the leaching of sulfide-rich gold minerals contaminating the aquifer system with hazardous elements. Transport of these contaminant has posed threat to the health of the urban population of Kolar township. A detailed survey of borewells, covering radius of 10 km of the KGF was carried out during pre and post-monsoon seasons and various parameters were assessed. Almost 80% of the water samples exceeded the regulatory limits of potable water criteria with excess arsenic (As; 12–127 μg/L), fluoride (F; <0.005 μg/L), dissolved salts (>500 mg/L). Water Quality Index (WQI) was used to understand the overall urban groundwater quality. At the centre of sampling circle core, mineral dissolution was found to be the function of pH, induced by acidophilic sulfur oxidizing bacteria. Modelling of predicted microbial metabolic pathways in metagenomics libraries using PICRUSt, indicated complex functional networks. High expression of siderophore proteins (> 2 cm halo in the chrome azurol test) caused Fe-sequestration, secondary Fe-mineral formation and subsequent release of As. Sulfide bearing Au-rich minerals (Arsenopyrite, Scorodite, Jarosite) were bio-weathered leading to release of H3AsO3+ at low pH, resulted in groundwater composition of Ca–HCO3 type and Ca–Na–HCO3 or Ca–Mg–Cl type.Sanitary Engineerin