3,364 research outputs found
The association between cardiorespiratory fitness and cardiometabolic risk in children is mediated by abdominal adiposity: the HAPPY study
Background: It is unclear whether cardiorespiratory fitness (CRF) is independently linked to cardiometabolic risk in children. This study investigated a) the association between CRF level and presence of cardiometabolic risk disorders using health-related cut points, and b) whether these associations were mediated by abdominal adiposity in children. Methods: This was a cross-sectional design study. Anthropometry, biochemical parameters and CRF were assessed in 147 schoolchildren (75 girls) aged 10-14 years. CRF was determined using a maximal cycle ergometer test. Children were classified as ‘fit’ or ‘unfit’ according to published thresholds. Logistic regression was used to investigate the odds of having individual and clustered cardiometabolic risk factors according to CRF level and whether abdominal adiposity mediated these associations. Results: Children classified as unfit had increased odds of presenting individual and clustered cardiometabolic risk factors (p 0.05). Conclusions: This study suggests that the association between CRF and cardiometabolic risk is mediated by abdominal adiposity in 10-14 year-old children and that abdominal adiposity may be a more important determinant of adverse cardiometabolic health in this age group
Fast C-V method to mitigate effects of deep levels in CIGS doping profiles
In this work, methods to determine more accurate doping profiles in
semiconductors is explored where trap-induced artifacts such as hysteresis and
doping artifacts are observed. Specifically in CIGS, it is shown that this fast
capacitance-voltage (C-V) approach presented here allows for accurate doping
profile measurement even at room temperature, which is typically not possible
due to the large ratio of trap concentration to doping. Using deep level
transient spectroscopy (DLTS) measurement, the deep trap responsible for the
abnormal C-V measurement above 200 K is identified. Importantly, this fast C-V
can be used for fast evaluation on the production line to monitor the true
doping concentration, and even estimate the trap concentration. Additionally,
the influence of high conductance on the apparent doping profile at different
temperature is investigated
Effects of breaking up prolonged sitting following low and high glycaemic index breakfast consumption on glucose and insulin concentrations
Purpose: Breaking up prolonged sitting can attenuate the postprandial rise in glucose and insulin. Whether such effects are dependent of the glycaemic index (GI) of the consumed carbohydrate is unknown. This study examined the acute effects of breaking up prolonged sitting following a low GI and a high GI breakfast on postprandial glucose and insulin concentrations. Procedures: Fourteen adult males aged 22.1 ± 1.2 years completed four, 4 h experimental conditions: high GI breakfast followed by uninterrupted sitting (HGI-SIT), low GI breakfast followed by uninterrupted sitting (LGI-SIT), high GI breakfast followed by 2 min activity breaks every 20 min (HGI-ACT), and low GI breakfast followed by 2 min activity breaks every 20 min (LGI-ACT). Positive incremental area under the curve (iAUC) for glucose and insulin (mean [95% CI]) for each 4h experimental condition was calculated. Statistical analyses were completed using linear mixed models. Results: The sitting × breakfast GI interaction was not significant for glucose positive iAUC (P=0.119). Glucose positive iAUC (mmol/L4 h−1) was significantly lower in the activity breaks conditions than the uninterrupted sitting conditions (2.07 [2.24, 2.89] vs. 2.56 [1.74, 2.40], respectively, P=0.004) and significantly lower in the low GI conditions than the high GI conditions (2.13 [1.80, 2.45] vs. 2.51 [2.18, 2.84], respectively, P=0.022). Insulin concentrations did not differ between conditions (P ≥ 0.203). Conclusions: Breaking up prolonged sitting and lowering breakfast GI independently reduced postprandial glucose responses. This indicates that interrupting prolonged sitting and reducing dietary GI are beneficial approaches for reducing cardiometabolic disease risk
The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study
Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3
High eccentricity planets from the Anglo-Australian Planet Search
We report Doppler measurements of the stars HD187085 and HD20782 which
indicate two high eccentricity low-mass companions to the stars. We find
HD187085 has a Jupiter-mass companion with a ~1000d orbit. Our formal `best
fit' solution suggests an eccentricity of 0.47, however, it does not sample the
periastron passage of the companion and we find that orbital solutions with
eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS
and chi^2) and are thus plausible. Observations made during periastron passage
in 2007 June should allow for the reliable determination of the orbital
eccentricity for the companion to HD187085. Our dataset for HD20782 does sample
periastron and so the orbit for its companion can be more reliably determined.
We find the companion to HD20782 has M sin i=1.77+/-0.22M_JUP, an orbital
period of 595.86+/-0.03d and an orbit with an eccentricity of 0.92+/-0.03. The
detection of such high-eccentricity (and relatively low velocity amplitude)
exoplanets appears to be facilitated by the long-term precision of the
Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we
find that those with higher eccentricity seem to have relatively higher
velocity amplitudes indicating higher mass planets and/or an observational bias
against the detection of high eccentricity systems.Comment: to appear in MNRA
Alterations in the Colonic Microbiota of Pigs Associated with Feeding Distillers Dried Grains with Solubles
In an effort to reduce feed costs, many pork producers have increased their use of coproducts of biofuel production in commercial pig diets, including increased feeding of distiller’s dried grains with solubles (DDGS). The inclusion of DDGS increases the insoluble fiber content in the ration, which has the potential to impact the colonic microbiota considerably as the large intestine contains a dynamic microenvironment with tremendous interplay between microorganisms. Any alteration to the physical or chemical properties of the colonic contents has the potential to impact the resident bacterial population and potentially favor or inhibit the establishment of pathogenic species. In the present study, colonic contents collected at necropsy from pigs fed either 30% or no DDGS were analyzed to examine the relative abundance of bacterial taxa associated with feeding this ingredient. No difference in alpha diversity (richness) was detected between diet groups. However, the beta diversity was significantly different between groups with feeding of DDGS being associated with a decreased Firmicutes:Bacteriodetes ratio (P = .004) and a significantly lower abundance of Lactobacillus spp. (P = .016). Predictive functional profiling of the microbiota revealed more predicted genes associated with carbohydrate metabolism, protein digestion, and degradation of glycans in the microbiota of pigs fed DDGS. Taken together, these findings confirm that alterations in dietary insoluble fiber significantly alter the colonic microbial profile of pigs and suggest the resultant microbiome may predispose to the development of colitis
Beneficial postprandial lipaemic effects of interrupting sedentary time with high-intensity physical activity versus a continuous moderate-intensity physical activity bout: a randomised crossover trial
Objectives
To compare the postprandial cardiometabolic response to prolonged sitting, continuous moderate-intensity physical activity (PA) followed by prolonged sitting, and interrupting prolonged sitting with hourly high-intensity PA breaks.
Design
Three-condition randomised crossover trial.
Methods
Fourteen sedentary and inactive adults aged 29 ± 9 years took part in three, 8-h conditions: (1) prolonged sitting (SIT), (2) a continuous 30-min moderate-intensity PA bout followed by prolonged sitting (CONT-SIT), and (3) sitting interrupted hourly with 2 min 32 s high-intensity PA bouts (SIT-ACT). The treadmill PA in conditions 2 and 3 were matched for energy expenditure. Two standardised test meals were consumed during each condition. Incremental area under the curve (iAUC) for each 8-h condition was calculated for glucose, insulin, triglyceride, and high-density lipoprotein cholesterol (HDL-C) concentrations. Statistical analyses were completed using linear mixed models.
Results
Compared with SIT, SIT-ACT lowered triglyceride iAUC by 2.23 mmol/L ∙ 8 h (95% CI −4.33, −0.13) and raised HDL-C iAUC by 0.99 mmol/L ∙ 8 h (0.05, 1.93) (all p ≤ 0.038). There was no significant difference in triglyceride or HDL-C iAUC between CONT-SIT and SIT or SIT-ACT (p ≥ 0.211). There were no significant differences between conditions for glucose or insulin iAUC (p ≥ 0.504).
Conclusions
This study suggests that interrupting prolonged sitting with hourly high-intensity PA breaks acutely improves postprandial triglyceride and HDL-C concentrations compared with prolonged sitting, whereas a continuous moderate-intensity PA bout does not
Neural Networks and the Classification of Active Galactic Nucleus Spectra
The use of Artificial Neural Networks (ANNs) as a classifier of digital
spectra is investigated. Using both simulated and real data, it is shown that
neural networks can be trained to discriminate between the spectra of different
classes of active galactic nucleus (AGN) with realistic sample sizes and
signal-to-noise ratios. By working in the Fourier domain, neural nets can
classify objects without knowledge of their redshifts.Comment: 11 pages, LaTeX, including two postscript figures, 41 kb. Accepted
for publication in Publ. AS
Detection of Planetary and Stellar Companions to Neighboring Stars via a Combination of Radial Velocity and Direct Imaging Techniques
13 pages, 6 figures, 4 tables, accepted for publication in the Astronomical Journal (submitted 25 Feb 2019; accepted 28 April 2019). Machine readable tables and Posteriors from the RadVel fits are available here: http://stephenkane.net/rvfits.tarThe sensitivities of radial velocity (RV) surveys for exoplanet detection are extending to increasingly longer orbital periods, where companions with periods of several years are now being regularly discovered. Companions with orbital periods that exceed the duration of the survey manifest in the data as an incomplete orbit or linear trend, a feature that can either present as the sole detectable companion to the host star, or as an additional signal overlain on the signatures of previously discovered companion(s). A diagnostic that can confirm or constrain scenarios in which the trend is caused by an unseen stellar rather than planetary companion is the use of high-contrast imaging observations. Here, we present RV data from the Anglo-Australian Planet Search (AAPS) for 20 stars that show evidence of orbiting companions. Of these, six companions have resolved orbits, with three that lie in the planetary regime. Two of these (HD 92987b and HD 221420b) are new discoveries. Follow-up observations using the Differential Speckle Survey Instrument (DSSI) on the Gemini South telescope revealed that 5 of the 20 monitored companions are likely stellar in nature. We use the sensitivity of the AAPS and DSSI data to place constraints on the mass of the companions for the remaining systems. Our analysis shows that a planetary-mass companion provides the most likely self-consistent explanation of the data for many of the remaining systems.Peer reviewedFinal Accepted Versio
Radiative Tau Lepton Pair Production as a Probe of Anomalous Electromagnetic Couplings of the Tau
We calculate the squared matrix element for the process e+ e- --> tau+ tau-
gamma allowing for anomalous magnetic and electric dipole moments at the tau
tau gamma vertex. No interferences are neglected and no approximations of light
fermion masses are made. We show that anomalous moments affect not only the
cross section, but also the shape of the photon energy and angular
distributions. We also demonstrate that in the case of the anomalous magnetic
dipole moment, the contribution from interference involving Standard Model and
anomalous amplitudes is significant compared to the contribution from anomalous
amplitudes alone. A program to perform the calculation is available and it may
be employed as a Monte Carlo generator.Comment: 14 pages, 8 figures submitted to Nuclear Physics
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