828 research outputs found
Differences in intestinal size, structure, and function contributing to feed efficiency in broiler chickens reared at geographically distant locations
The contribution of the intestinal tract to differences in residual feed intake (RFI) has been inconclusively studied in chickens so far. It is also not clear if RFI-related differences in intestinal function are similar in chickens raised in different environments. The objective was to investigate differences in nutrient retention, visceral organ size, intestinal morphology, jejunal permeability and expression of genes related to barrier function, and innate immune response in chickens of diverging RFI raised at 2 locations (L1: Austria; L2: UK). The experimental protocol was similar, and the same dietary formulation was fed at the 2 locations. Individual BW and feed intake (FI) of chickens (Cobb 500FF) were recorded from d 7 of life. At 5 wk of life, chickens (L1, n = 157; L2 = 192) were ranked according to their RFI, and low, medium, and high RFI chickens were selected (n = 9/RFI group, sex, and location). RFI values were similar between locations within the same RFI group and increased by 446 and 464 g from low to high RFI in females and males, respectively. Location, but not RFI rank, affected growth, nutrient retention, size of the intestine, and jejunal disaccharidase activity. Chickens from L2 had lower total body weight gain and mucosal enzyme activity but higher nutrient retention and longer intestines than chickens at L1. Parameters determined only at L1 showed increased crypt depth in the duodenum and jejunum and enhanced paracellular permeability in low vs. high RFI females. Jejunal expression of IL1B was lower in low vs. high RFI females at L2, whereas that of TLR4 at L1 and MCT1 at both locations was higher in low vs. high RFI males. Correlation analysis between intestinal parameters and feed efficiency metrics indicated that feed conversion ratio was more correlated to intestinal size and function than was RFI. In conclusion, the rearing environment greatly affected intestinal size and function, thereby contributing to the variation in chicken RFI observed across locations
Nutritional supplements, leptin, insulin and progesterone in female Australian Cashmere goats
In small ruminants, reproductive wastage due to early embryo mortality is a major industry issue because it reduces reproductive efficiency and limits productivity. In sheep, early embryo mortality appears to be caused by reductions in progesterone concentrations when animals are over-fed, but this concept has not been studied in goats. Therefore we tested whether a supplement of lupin grain affects circulating progesterone concentrations in Cashmere goats during non- breeding season. We allocated 23 females into two groups: Controls were fed to ensure maintenance of body mass (85% chaff, 15% lupins head daily); Supplemented goats were fed twice their daily requirements for maintenance. All animals were anovulatory and treated with CIDRs to supply exogenous progesterone at a relatively constant rate. Nutritional treatments lasted for 18 days, and coincided with the presence of CIDRs. Leptin and insulin concentrations were increased (p < 0.05) by supplementation, but progesterone concentrations did not significant differ between groups at any time during the experiment. We conclude that a dietary supplement that elicits major changes in energy homeostasis does not reduce progesterone concentrations in goats and is thus unlikely to affect embryo mortality
Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults.
PURPOSE: An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs. METHODS: Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions. RESULTS: Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p < 0.05). No differences in neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP. CONCLUSION: The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP and SPP. In addition, future work should examine the influence on the neuromuscular control of the magnitude of the perturbations and the magnitude of stepping height and stepping distance
Maintenance inhaler therapy preferences of patients with asthma or chronic obstructive pulmonary disease:a discrete choice experiment
Background A variety of maintenance inhaler therapies are available to treat asthma and COPD. Patient-centric treatment choices require understanding patient preferences for the alternative therapies. Methods A self-completed web-based discrete choice experiment was conducted to elicit patient preferences for inhaler device and medication attributes. Selection of attributes was informed by patient focus groups and literature review. Results The discrete choice experiment was completed by 810 patients with asthma and 1147 patients with COPD. Patients with asthma most valued decreasing the onset of action from 30 to 5 min, followed by reducing yearly exacerbations from 3 to 1. Patients with COPD most and equally valued decreasing the onset of action from 30 to 5 min and reducing yearly exacerbations from 3 to 1. Both patients with asthma and patients with COPD were willing to accept an additional exacerbation in exchange for a 15 min decrease in onset of action and a longer onset of action in exchange for a lower risk of adverse effects from inhaled corticosteroids. Patients with asthma and COPD valued once-daily over twice-daily dosing, pressurised inhalers over dry powder inhalers and non-capsule priming over single-use capsules, although these attributes were not valued as highly as faster onset of action or reduced exacerbations. Conclusions The most important maintenance inhaler attributes for patients with asthma and COPD were fast onset of symptom relief and a lower rate of exacerbations. Concerns about safety of inhaled corticosteroids and device convenience also affected patient preferences but were less important
Clinical trials in myasthenia gravis
Myasthenia Gravis is a chronic autoimmune disease associated with autoantibodies that are directed against post synaptic acetyl choline receptors in 80–88%. Although in many cases initial diagnosis and management is relatively straightforward, myasthenia remains a life-long condition without cure. Current treatment strategies are directed towards symptomatic relief with cholinesterase inhibitors and, in a proportion of patients, suppression of the immune response with the use of steroids and/or longer-term immunosuppressant strategies including oral immunosuppressants, plasma exchange, intravenous immunoglobulin, thymectomy, etc., many of which have significant side effects. Around 50% of patients will not respond to conventional treatment and disease course is often unpredictable with life-threatening myasthenic crises affecting 15–20% of patients at least once during their lives. In addition to the burden of disease on the individual, it has also been estimated that the financial cost from hospital admissions alone as a result of myasthenia was more than €450 million per year in Europe in 2010, and over $500 million in the USA in 2013
Early impact of Medicare accountable care organizations on cancer surgery outcomes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134271/1/cncr30111.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134271/2/cncr30111_am.pd
Large Eddy Simulation of acoustic pulse propagation and turbulent flow interaction in expansion mufflers
A novel hybrid pressure-based compressible solver is developed and validated for low Mach number acoustic flow simulation. The solver is applied to the propagation of an acoustic pulse in a simple expansion muffler, a configuration frequently employed in HVAC and automotive exhaust systems. A set of benchmark results for experimental analysis of the simple expansion muffler both with and without flow are obtained to compare attenuation in forced pulsation for various mean-flow velocities. The experimental results are then used for validation of the proposed pressure-based compressible solver. Compressible, Unsteady Reynolds Averaged Navier-Stokes (URANS) simulation of a muffler with a mean through flow is conducted and results are presented to demonstrate inherent limitations associated with this approach. Consequently, a mixed synthetic inflow boundary condition is developed and validated for compressible Large Eddy Simulation (LES) of channel flow. The mixed synthetic boundary is then employed for LES of a simple expansion muffler to analyse the flow-acoustic and acoustic-pulse interactions inside the expansion muffler. The improvement in the prediction of vortex shedding inside the chamber is highlighted in comparison to the URANS method. Further, the effect of forced pulsation on flow-acoustic is observed in regard to the shift in Strouhal number inside the simple expansion muffler
Gravitational Flexion by Elliptical Dark Matter Haloes
We present equations for the gravitational lensing flexion expected for an
elliptical lens mass distribution. These can be reduced to one-dimensional
finite integrals, thus saving significant computing time over a full
two-dimensional calculation. We estimate constraints on galaxy halo
ellipticities for a range of potential future surveys, finding that the
constraints from the two different types of flexion are comparable and are up
to two orders of magnitude tighter than those from shear. Flexion therefore
appears to be a very promising potential tool for constraining the shapes of
galaxy haloes from future surveys.Comment: 7 pages, 5 figures, submitted to MNRA
A High-resolution Adaptive Moving Mesh Hydrodynamic Algorithm
An algorithm for simulating self-gravitating cosmological astrophysical
fluids is presented. The advantages include a large dynamic range,
parallelizability, high resolution per grid element and fast execution speed.
The code is based on a finite volume flux conservative
Total-Variation-Diminishing (TVD) scheme for the shock capturing hydro, and an
iterative multigrid solver for the gravity. The grid is a time dependent field,
whose motion is described by a generalized potential flow. Approximately
constant mass per cell can be obtained, providing all the advantages of a
Lagrangian scheme. The grid deformation combined with appropriate limiting and
smoothing schemes guarantees a regular and well behaved grid geometry, where
nearest neighbor relationships remain constant. The full hydrodynamic fluid
equations are implemented in the curvilinear moving grid, allowing for
arbitrary fluid flow relative to the grid geometry. This combination retains
all the advantages of the grid based schemes including high speed per fluid
element and a rapid gravity solver.
The current implementation is described, and empirical simulation results are
presented. Accurate execution speed calculations are given in terms of floating
point operations per time step per grid cell. This code is freely available to
the community.Comment: 53 pages including 14 figures, submitted to ApJ
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