1,297 research outputs found
Effect of Supplemental Fat from Dried Distillers Grains with Solubles or Corn Oil on Nutrient Digestibility
The objective of this experiment was to determine the effects of supplemental fat from either dried distillers grains with solubles (DDGS) or raw corn oil on the digestibility of nutrients and long chain fatty acids. When compared to corn grain and grass hay, DDGS have considerably greater levels of fat, which may negatively influence rumen microbes and nutrient digestibility. Six mediumâframed crossbred steers (initial BW = 602 ± 23.6 lb) were used in a Latin square design to determine apparent total tract digestibility of diets formulated with no supplemental fat or supplemental fat from either DDGS or raw corn oil. Steers were randomly assigned to of 1 of 3 dietary treatments: 1) supplemental fat from DDGS (DG); 2) supplemental fat from corn oil (OIL); 3) no supplemental fat (NO OIL; Table 1). The DG treatment was comprised solely of dried distillers grains with solubles (DDGS). The OIL treatment was comprised of a combination of highâprotein dried distillers grains (HP DDG), corn bran, and corn oil formulated to be isonitrogenous and isolipid to the DG treatment. The final dietary treatment (NO OIL) was a combination of HP DDG and corn bran formulated to be isonitrogenous to the DG and OIL treatments, but with no additional fat. Treatment diets were administered over 3 consecutive 19 d feeding periods that consisted of 14 d diet adaptation followed by 5 d total collection. No differences were observed for DM, OM, ADF, NDF, or N, digestibility. Ether extract digestibility was lower in NO OIL compared to DG and OIL. Apparent digestibility of C17:0 was the lowest for OIL and greatest for DG; NO OIL was intermediate but different from both DG and OIL. C18:0 apparent digestibility was greatest for DG, lowest for OIL; NO OIL was intermediate but not different from either DG and OIL. C18:1c9 digestibility was greatest for DG, intermediate for OIL and least for NO OIL. Apparent digestibility of C20:3, C20:5, C22:2, total C20, and total conjugated linoleic acid were greater in DG and OIL than in NO OIL. These results suggest that providing low concentrations of supplemental fat as either DDGS or raw corn oil to growing steers on high forage diets will not influence digestibilities of DM, OM, ADF, NDF, or N. Digestibilities of ether extract and certain FA are affected by fat inclusion. Low levels of supplemental fat from either DDGS or corn oil may be included in highâforage rations fed to growing beef steers with no adverse affects on digestibility of nutrients or FA
Spin relaxation in a complex environment
We report the study of a model of a two-level system interacting in a
non-diagonal way with a complex environment described by Gaussian orthogonal
random matrices (GORM). The effect of the interaction on the total spectrum and
its consequences on the dynamics of the two-level system are analyzed. We show
the existence of a critical value of the interaction, depending on the mean
level spacing of the environment, above which the dynamics is self-averaging
and closely obey a master equation for the time evolution of the observables of
the two-level system. Analytic results are also obtained in the strong coupling
regimes. We finally study the equilibrium values of the two-level system
population and show under which condition it thermalizes to the environment
temperature.Comment: 45 pages, 49 figure
Quantum master equation for a system influencing its environment
A perturbative quantum master equation is derived for a system interacting
with its environment, which is more general than the ones derived before. Our
master equation takes into account the effect of the energy exchanges between
the system and the environment and the conservation of energy in a finite total
system. This master quantum describes relaxation mechanisms in isolated
nanoscopic quantum systems. In its most general form, this equation is
non-Markovian and a Markovian version of it rules the long-time relaxation. We
show that our equation reduces to the Redfield equation in the limit where the
energy of the system does not affect the density of state of its environment.
This master equation and the Redfield one are applied to a spin-environment
model defined in terms of random matrices and compared with the solutions of
the exact von Neumann equation. The comparison proves the necessity to allow
energy exchange between the subsystem and the environment in order to correctly
describe the relaxation in isolated nanoscopic total system.Comment: 39 pages, 10 figure
Interface modeling in incompressible media using level sets in Escript
We use a finite element (FEM) formulation of the level set method to model geological fluid flow problems involving interface propagation. Interface problems are ubiquitous in geophysics. Here we focus on a Rayleigh-Taylor instability, namely mantel plumes evolution, and the growth of lava domes. Both problems require the accurate description of the propagation of an interface between heavy and light materials (plume) or between high viscous lava and low viscous air (lava dome), respectively. The implementation of the models is based on Escript which is a Python module for the solution of partial differential equations (PDEs) using spatial discretization techniques such as FEM. It is designed to describe numerical models in the language of PDEs while using computational components implemented in C and C++ to achieve high performance for time-intensive, numerical calculations. A critical step in the solution geological flow problems is the solution of the velocity-pressure problem. We describe how the Escript module can be used for a high-level implementation of an efficient variant of the well-known Uzawa scheme. We begin with a brief outline of the Escript modules and then present illustrations of its usage for the numerical solutions of the problems mentioned above
Autoantibodies to selenoprotein P in chronic fatigue syndrome suggest selenium transport impairment and acquired resistance to thyroid hormone
Chronic Fatigue Syndrome (CFS) presents with symptoms of hypothyroidism, including mental and physical fatigue, poor sleep, depression, and anxiety. However, thyroid hormone (TH) profiles of elevated thyrotropin and low thyroxine (T4) are not consistently observed. Recently, autoantibodies to the Se transporter SELENOP (SELENOP-aAb) have been identified in Hashimoto's thyroiditis and shown to impair selenoprotein expression. We hypothesized that SELENOP-aAb are prevalent in CFS, and associate with reduced selenoprotein expression and impaired TH deiodination.
Se status and SELENOP-aAb prevalence was compared by combining European CFS patients (n = 167) and healthy controls (n = 545) from different sources. The biomarkers total Se, glutathione peroxidase (GPx3) and SELENOP showed linear correlations across the samples without reaching saturation, indicative of Se deficiency. SELENOP-aAb prevalence was 9.6-15.6% in CFS versus 0.9-2.0% in controls, depending on cut-off for positivity. The linear correlation between Se and GPx3 activity was absent in SELENOP-aAb positive patients, suggesting impaired Se supply of kidney. A subgroup of paired control (n = 119) and CSF (n = 111) patients had been characterized for TH and biochemical parameters before. Within this subgroup, SELENOP-aAb positive patients displayed particularly low deiodinase activity (SPINA-GD index), free T3 levels, total T3 to total T4 (TT3/TT4) and free T3 to free T4 (FT3/FT4) ratios. In 24 h urine, iodine concentrations were significantly lower in SELENOP-aAb positive than in SELENOP-aAb negative patients or controls (median (IQR); 43.2 (16.0) vs. 58.9 (45.2) vs. 89.0 (54.9) & mu;g/L). The data indicate that SELENOP-aAb associate with low deiodination rate and reduced activation of TH to active T3.
We conclude that a subset of CFS patients express SELENOP-aAb that disturb Se transport and reduce sele-noprotein expression in target tissues. Hereby, TH activation decreases as an acquired condition not reflected by thyrotropin and T4 in blood. This hypothesis opens new diagnostic and therapeutic options for SELENOP-aAb positive CFS, but requires clinical evidence from intervention trials
Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion
The masses of the negative parity SU(6) 70-plet baryons are analyzed in the
1/Nc expansion to order 1/Nc and to first order in SU(3) breaking. At this
level of precision there are twenty predictions. Among them there are the well
known Gell-Mann Okubo and equal spacing relations, and four new relations
involving SU(3) breaking splittings in different SU(3) multiplets. Although the
breaking of SU(6) symmetry occurs at zeroth order in 1/Nc, it turns out to be
small. The dominant source of the breaking is the hyperfine interaction which
is of order 1/Nc. The spin-orbit interaction, of zeroth order in 1/Nc, is
entirely fixed by the splitting between the singlet states Lambda(1405) and
Lambda(1520), and the spin-orbit puzzle is solved by the presence of other
zeroth order operators involving flavor exchange.Comment: 31 pages, 3 figure
Relations between lipoprotein(a) concentrations, LPA genetic variants, and the risk of mortality in patients with established coronary heart disease: a molecular and genetic association study
Background:
Lipoprotein(a) concentrations in plasma are associated with cardiovascular risk in the general population. Whether lipoprotein(a) concentrations or LPA genetic variants predict long-term mortality in patients with established coronary heart disease remains less clear.
Methods:
We obtained data from 3313 patients with established coronary heart disease in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. We tested associations of tertiles of lipoprotein(a) concentration in plasma and two LPA single-nucleotide polymorphisms ([SNPs] rs10455872 and rs3798220) with all-cause mortality and cardiovascular mortality by Cox regression analysis and with severity of disease by generalised linear modelling, with and without adjustment for age, sex, diabetes diagnosis, systolic blood pressure, BMI, smoking status, estimated glomerular filtration rate, LDL-cholesterol concentration, and use of lipid-lowering therapy. Results for plasma lipoprotein(a) concentrations were validated in five independent studies involving 10â195 patients with established coronary heart disease. Results for genetic associations were replicated through large-scale collaborative analysis in the GENIUS-CHD consortium, comprising 106â353 patients with established coronary heart disease and 19â332 deaths in 22 studies or cohorts.
Findings:
The median follow-up was 9·9 years. Increased severity of coronary heart disease was associated with lipoprotein(a) concentrations in plasma in the highest tertile (adjusted hazard radio [HR] 1·44, 95% CI 1·14â1·83) and the presence of either LPA SNP (1·88, 1·40â2·53). No associations were found in LURIC with all-cause mortality (highest tertile of lipoprotein(a) concentration in plasma 0·95, 0·81â1·11 and either LPA SNP 1·10, 0·92â1·31) or cardiovascular mortality (0·99, 0·81â1·2 and 1·13, 0·90â1·40, respectively) or in the validation studies.
Interpretation:
In patients with prevalent coronary heart disease, lipoprotein(a) concentrations and genetic variants showed no associations with mortality. We conclude that these variables are not useful risk factors to measure to predict progression to death after coronary heart disease is established.
Funding:
Seventh Framework Programme for Research and Technical Development (AtheroRemo and RiskyCAD), INTERREG IV Oberrhein Programme, Deutsche Nierenstiftung, Else-Kroener Fresenius Foundation, Deutsche Stiftung fĂŒr Herzforschung, Deutsche Forschungsgemeinschaft, Saarland University, German Federal Ministry of Education and Research, Willy Robert Pitzer Foundation, and Waldburg-Zeil Clinics Isny
Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider
This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the Ï(4S), Ï(3S), and Ï(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-âe+e- and (for the Ï(4S) only) e+e-âÎŒ+ÎŒ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-âe+e- and e+e-âÎŒ+ÎŒ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the Ï(3S) and Ï(2S) resonances, an additional uncertainty arises due to Ïâe+e-X background. For data collected off the Ï resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the Ï(4S), 0.58% (0.72%) for the Ï(3S), and 0.68% (0.88%) for the Ï(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat Ă lâEnergie Atomique and Institut National de Physique NuclĂ©aire et de Physiquedes Particules (France), the Bundesministerium fĂŒr Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e InnovaciĂłn (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)
The complex physics of dusty star-forming galaxies at high redshifts as revealed by Herschel and Spitzer
We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from
Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous
infrared galaxies ((U)LIRGs) at z ⌠1 and 2 selected in GOODS-S with 24Όm fluxes between 0.2 and 0.5 mJy.We
model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust
extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr)
stars and, at the same time, to host a moderate ongoing activity of star formation (SFR 100M yrâ1). The bulk of
the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of
the sample require a recent starburst superimposed on a quiescent star formation history.We also find discrepancies
between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects;
by fitting their observed SEDs with our physical model we find higher extinctions (by ÎAV ⌠0.81 and 1.14)
and higher stellar masses (by Îlog(M ) ⌠0.16 and 0.36 dex) for z ⌠1 and z ⌠2 (U)LIRGs, respectively. The
stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed
from LIR using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age
stellar populations through âcirrusâ emission (âŒ73% and âŒ66% of the total LIR for z ⌠1 and z ⌠2 (U)LIRGs,
respectively).Department of HE and Training approved lis
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