738 research outputs found
Novel Method for Incorporating Model Uncertainties into Gravitational Wave Parameter Estimates
Posterior distributions on parameters computed from experimental data using
Bayesian techniques are only as accurate as the models used to construct them.
In many applications these models are incomplete, which both reduces the
prospects of detection and leads to a systematic error in the parameter
estimates. In the analysis of data from gravitational wave detectors, for
example, accurate waveform templates can be computed using numerical methods,
but the prohibitive cost of these simulations means this can only be done for a
small handful of parameters. In this work a novel method to fold model
uncertainties into data analysis is proposed; the waveform uncertainty is
analytically marginalised over using with a prior distribution constructed by
using Gaussian process regression to interpolate the waveform difference from a
small training set of accurate templates. The method is well motivated, easy to
implement, and no more computationally expensive than standard techniques. The
new method is shown to perform extremely well when applied to a toy problem.
While we use the application to gravitational wave data analysis to motivate
and illustrate the technique, it can be applied in any context where model
uncertainties exist.Comment: 6 pages, 3 figures, accepted for publication in Physical Review
Letter
Biomechanical, ultrastructural, and electrophysiological characterization of the non-human primate experimental glaucoma model.
Laser-induced experimental glaucoma (ExGl) in non-human primates (NHPs) is a common animal model for ocular drug development. While many features of human hypertensive glaucoma are replicated in this model, structural and functional changes in the unlasered portions of trabecular meshwork (TM) of laser-treated primate eyes are understudied. We studied NHPs with ExGl of several years duration. As expected, ExGl eyes exhibited selective reductions of the retinal nerve fiber layer that correlate with electrophysiologic measures documenting a link between morphologic and elctrophysiologic endpoints. Softening of unlasered TM in ExGl eyes compared to untreated controls was observed. The degree of TM softening was consistent, regardless of pre-mortem clinical findings including severity of IOP elevation, retinal nerve fiber layer thinning, or electrodiagnostic findings. Importantly, this softening is contrary to TM stiffening reported in glaucomatous human eyes. Furthermore, microscopic analysis of unlasered TM from eyes with ExGl demonstrated TM thinning with collapse of Schlemm's canal; and proteomic analysis confirmed downregulation of metabolic and structural proteins. These data demonstrate unexpected and compensatory changes involving the TM in the NHP model of ExGl. The data suggest that compensatory mechanisms exist in normal animals and respond to elevated IOP through softening of the meshwork to increase outflow
Translocation dynamics of freely jointed Lennard-Jones chains into adsorbing pores
Polymer translocation into adsorbing nanopores is studied by using the Fokker-Planck equation of chain diffusion along the energy landscape calculated with Monte Carlo simulations using the incremental gauge cell method. The free energy profile of a translocating chain was found by combining two independent sub-chains, one free but tethered to a hard wall, and the other tethered inside an adsorbing pore. Translocation dynamics were revealed by application of the Fokker-Planck equation for normal diffusion. Adsorption of polymer chains into nanopores involves a competition of attractive adsorption and repulsive steric hindrance contributions to the free energy. Translocation times fell into two regimes depending on the strength of the adsorbing pore. In addition, we found a non-monotonic dependence of translocation times with increasing adsorption strength, with sharp peak associated with local free energy minima along the translocation coordinate
The Evolution of Galaxies in X-ray Luminous Groups
We investigate the galaxy populations in seven X-ray selected,
intermediate-redshift groups (0.2<z<0.6). Overall, the galaxy populations in
these systems are similar to those in clusters at the same redshift; they have
large fractions of early-type galaxies (f_e~70%) and small fractions of
galaxies with significant star formation (f_[OII]~30%). We do not observe a
strong evolution in the galaxy populations from those seen in X-ray luminous
groups at low-redshift. Both f_e and f_[OII] are correlated with radius but do
not reach the field value out to ~r_500. However, we find significant variation
in the galaxy populations between groups with some groups having field-like
populations. Comparisons between the morphological and spectral properties of
group galaxies reveal both gas-poor mergers and a population of passive
spirals. Unlike low-redshift, X-ray emitting groups, in some of these groups
the brightest galaxy does not lie at the center of the X-ray emission, and in
several of the groups that do have a central BGG, the BGG has multiple
components. These groups appear to represent a range of evolutionary stages in
the formation of the BGG. Some groups have relatively large central galaxy
densities, and one group contains a string of seven bright galaxies within a
radius of 200 kpc that have a lower velocity dispersion than the rest of the
system. None of the central galaxies, including those with multiple components,
have significant [OII] emission. These observations support a scenario in which
BGGs are formed relatively late through gas-poor mergers.Comment: 50 pages, 8 figures, minor revisons to make consistent with published
version, for version with full resolution figures, see
http://www.ociw.edu/~tesla/groups.ps.g
Muscle fiber and performance adaptations to resistance exercise with MyoVive, colostrum or casein and whey supplementationa
This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?sid=ba69ee0d-97cf-4a2c-a1a2-2c26fb60d65c%40sessionmgr13&vid=1&hid=2&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=10725638To determine the effects of 12 weeks of resistance exercise with MyoVive
and/or colostrum supplementation, 19 male and female recreationally weighttrained
subjects (X ± SE; age = 28.3 ± 6.9 yrs; hgt = 68.2 ± 3.8 cm) were
divided into MyoVive + colostrum (n = 4), MyoVive + casein & whey (n
= 4), colostrum + casein & whey (n = 6), and casein & whey (n = 5) groups.
All groups similarly increased (p < .05) 1 repetition maximum (RM) leg press
(kg; pre = 158.6 ± 12.8, post = 189.3 ± 11.3), body mass (kg; pre = 79.0 ±
3.2, post = 80.7 ± 3.8), and lean body mass (kg; pre = 60.1 ± 3.1, post = 62.2
± 2.8). Increases were observed for peak force (N; all loads), peak velocity
(m.s-1; 70% & 40% 1 RM), and peak power (W; 70% & 40% 1 RM) for all
groups for the leg press exercise, with no differences between groups. When
performance data were adjusted for body mass, lean body mass, lower body
lean mass as determined by DEXA, or % change, no group differences were
observed. Relative (%) fiber type content, cross-sectional areas (mm2), % fiber
type areas, or % myosin heavy chain expression did not change for any
group. These data suggest that MyoVive and colostrum supplementation
have no greater effect on cellular and performance adaptations when compared
to casein and whey protein
Nonparametric Bayesian inference for perturbed and orthologous gene regulatory networks
Motivation: The generation of time series transcriptomic datasets collected under multiple experimental conditions has proven to be a powerful approach for disentangling complex biological processes, allowing for the reverse engineering of gene regulatory networks (GRNs). Most methods for reverse engineering GRNs from multiple datasets assume that each of the time series were generated from networks with identical topology. In this study, we outline a hierarchical, non-parametric Bayesian approach for reverse engineering GRNs using multiple time series that can be applied in a number of novel situations including: (i) where different, but overlapping sets of transcription factors are expected to bind in the different experimental conditions; that is, where switching events could potentially arise under the different treatments and (ii) for inference in evolutionary related species in which orthologous GRNs exist. More generally, the method can be used to identify context-specific regulation by leveraging time series gene expression data alongside methods that can identify putative lists of transcription factors or transcription factor targets.
Results: The hierarchical inference outperforms related (but non-hierarchical) approaches when the networks used to generate the data were identical, and performs comparably even when the networks used to generate data were independent. The method was subsequently used alongside yeast one hybrid and microarray time series data to infer potential transcriptional switches in Arabidopsis thaliana response to stress. The results confirm previous biological studies and allow for additional insights into gene regulation under various abiotic stresses.
Availability: The methods outlined in this article have been implemented in Matlab and are available on request
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Probabilistic 21st and 22nd Century Sea-Level Projections at a Global Network of Tide-Gauge Sites
Sea-level rise due to both climate change and non-climatic factors threatens coastal settlements, infrastructure, and ecosystems. Projections of mean global sea-level (GSL) rise provide insufficient information to plan adaptive responses; local decisions require local projections that accommodate different risk tolerances and time frames and that can be linked to storm surge projections. Here we present a global set of local sea-level (LSL) projections to inform decisions on timescales ranging from the coming decades through the 22nd century. We provide complete probability distributions, informed by a combination of expert community assessment, expert elicitation, and process modeling. Between the years 2000 and 2100, we project a very likely (90% probability) GSL rise of 0.51.2m under representative concentration pathway (RCP) 8.5, 0.40.9m under RCP 4.5, and 0.30.8m under RCP 2.6. Site-to-site differences in LSL projections are due to varying non-climatic background uplift or subsidence, oceanographic effects, and spatially variable responses of the geoid and the lithosphere to shrinking land ice. The Antarctic ice sheet (AIS) constitutes a growing share of variance in GSL and LSL projections. In the global average and at many locations, it is the dominant source of variance in late 21st century projections, though at some sites oceanographic processes contribute the largest share throughout the century. LSL rise dramatically reshapes flood risk, greatly increasing the expected number of 1-in-10 and 1-in-100 year events
Empirical evidence for stability of the 405-kiloyear Jupiter-Venus eccentricity cycle over hundreds of millions of years
The NewarkâHartford astrochronostratigraphic polarity timescale (APTS) was developed using a theoretically constant 405-kiloyear eccentricity cycle linked to gravitational interactions with JupiterâVenus as a tuning target and provides a major timing calibration for about 30 million years of Late Triassic and earliest Jurassic time. While the 405-ky cycle is both unimodal and the most metronomic of the major orbital cycles thought to pace Earthâs climate in numerical solutions, there has been little empirical confirmation of that behavior, especially back before the limits of orbital solutions at about 50 million years before present. Moreover, the APTS is anchored only at its younger end by UâPb zircon dates at 201.6 million years before present and could even be missing a number of 405-ky cycles. To test the validity of the dangling APTS and orbital periodicities, we recovered a diagnostic magnetic polarity sequence in the volcaniclastic-bearing Chinle Formation in a scientific drill core from Petrified Forest National Park (Arizona) that provides an unambiguous correlation to the APTS. New high precision UâPb detrital zircon dates from the core are indistinguishable from ages predicted by the APTS back to 215 million years before present. The agreement shows that the APTS is continuous and supports a stable 405-kiloyear cycle well beyond theoretical solutions. The validated NewarkâHartford APTS can be used as a robust framework to help differentiate provinciality from global temporal patterns in the ecological rise of early dinosaurs in the Late Triassic, amongst other problems
Single-Arm, Non-randomized, Time Series, Single-Subject Study of Fecal Microbiota Transplantation in Multiple Sclerosis
Emerging evidence suggests intestinal microbiota as a central contributing factor to the pathogenesis of Relapsing-Remitting-Multiple-Sclerosis (RRMS). This novel RRMS study evaluated the impact of fecal-microbiota-transplantation (FMT) on a broad array of physiological/clinical outcomes using deep metagenome sequencing of fecal microbiome. FMT interventions were associated with increased abundances of putative beneficial stool bacteria and short-chain-fatty-acid metabolites, which were associated with increased/improved serum brain-derived-neurotrophic-factor levels and gait/walking metrics. This proof-of-concept single-subject longitudinal study provides evidence of potential importance of intestinal microbiota in the pathogenesis of MS, and scientific rationale to help design future randomized controlled trials assessing FMT in RRMS patients
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