6,451 research outputs found

    Effect of variety, growing region and growing season on digestible energy content of wheats grown in Western Australia for weaner pigs

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    An experiment was conducted to examine the digestible energy (DE) content for weanling pigs in a cohort of wheats grown in Western Australia, and to establish relationships between DE content and their chemical composition. The 3 5 3 5 2 factorial experiment examined the wheat variety (Arrino, Stiletto and Westonia), growing location (high, medium and low rainfall zone) and harvest year (1999 and 2000). Pigs (no. = 5 per diet) aged about 28 days were given a diet at a level of 0.05 5 live weight containing 900 g/kg of the wheat and an acid-insoluble ash marker for 10 days, with samples of faeces collected from each pig for the final 5 days. The average live weight of pigs was 6.6 (s.d. 0.77) kg. The DE content of wheats harvested in 1999 varied by up to 1.3 MJ/kg, while wheats harvested in 2000 varied by up to 1.8 MJ/kg. When the 2 years' data were combined, the DE content ranged from 12.5 to 14.4 MJ/kg. Both the variety and growing region significantly influenced (P 0.05) with the wheats harvested in 2000. In addition, the precipitation level (mm) during the growing season of wheats was strongly correlated (r = -0.821, P < 0.01) to the DE content of wheat in year 1999, but was not correlated in 2000. The results indicate that the genetic and environmental conditions during the growth of wheat have a significant impact on the utilization of plant energy in weaner pigs, and that greater attention needs to be paid to these influences in the assignment of energy values for wheats given to weaner pigs

    Performance and intestinal responses to dehulling and inclusion level of Australian sweet lupins (Lupinus angustifolius L.) in diets for weaner pigs

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    A total of 180 entire male weaner pigs weighing 6.4 ± 0.1. kg (mean ± SEM) and housed in pairs was used in a completely randomised block design with 9 dietary treatments (n= 10 pens). Pigs were blocked based on weaning weight. The diets were (i) a wheat-based control diet containing 240. g/kg of milk products (whey and skim milk powder), and (ii) 8 diets containing whole or dehulled lupins (cv. Coromup) that substituted the milk products at 60, 120, 180 and 240. g/kg of diet (replace 25%, 50%, 75%, or 100% of the milk products in the control diets). The diets were isoenergetic [15. MJ digestible energy (DE)/kg], and were formulated to contain the same ileal standardised digestible lysine content (0.85. g/MJ DE) and ideal patterns of other essential amino acids. Pigs receiving 240. g/kg of dehulled lupins grew slower (P<0.05) than pigs fed the other diets mainly due to decreased feed intake. Pigs fed diets containing more than 180. g/kg of dehulled lupins had a higher faecal β-haemolytic Escherichia coli score on day 3 after weaning (P<0.05). Moreover, inclusion of 240. g/kg of whole lupin or more than 180. g/kg of dehulled lupins increased (P<0.001) plasma urea nitrogen (PUN) levels. Total tract apparent digestibility (TTAD) of dry matter decreased (P<0.001) in all lupin diets compared with the control diet. These data indicate that inclusion of dehulled lupin immediately after weaning should be limited to less than 180. g/kg whilst whole lupins can be included up to 240. g/kg without deleterious effects on production and intestinal health

    Efficacy of a reduced protein diet on clinical expression of post-weaning diarrhoea and life-time performance after experimental challenge with an enterotoxigenic strain of Escherichia coli

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    Previous experiments have shown that feeding a reduced protein diet within the first 2 weeks post-weaning reduces gastrointestinal protein fermentation and clinical expression of post-weaning diarrhoea (PWD). However, growth of young pigs receiving a reduced protein diet without crystalline essential amino acids (CEAA) supplementation is depressed after weaning. It has been argued that the short-term performance reduction caused by feeding a reduced protein diet would be compensated and the lifetime performance of pigs would not be affected. An experiment was therefore conducted to examine PWD and lifetime growth of pigs after feeding a reduced protein diet without and with CEAA supplementation for 2 weeks after weaning. Two hundred individually housed pigs weaned at 21 d of age (Large White×Landrace, castrate:female ratio of 1:1, mean±SEM body weight of 5.5±0.05kg) were stratified to one of four dietary treatments (n=50): High protein+antimicrobial compound diet (HP+AMC, 230g crude protein (CP) with 2.5g lincospectin and 3g zinc oxide per kg feed), High protein diet (HP, 230gCP/kg), Reduced protein+amino acid supplemented diet (RP+AA, 185gCP/kg with added CEAA up to HP level), and Reduced protein diet (RP, 185g CP/kg without CEAA supplementation). Pigs were fed the experimental diet for 2 weeks and then all pigs were fed the same series of commercial diets until slaughter. All pigs were experimentally infected with an enterotoxigenic strain of E. coli (6 and 10mL of 1.9×109cfu/mL, serotype O149:K91:K88) at 72, and 96h after weaning. Infection increased plasma haptoglobin levels (P0.05). Carcass characteristics were not affected (P>0.05) by the treatments. The results indicate that although feeding a RP diet without CEAA supplementation decreased performance after weaning, it did not influence lifetime performance or carcass characteristics and reduced the clinical expression of PWD

    Size Dependence of the Magnetic and Electrical Properties of the Spin-Valve Transistor

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    The electrical and magnetic properties of the spin-valve transistor (SVT) are investigated as a function of transistor size. A new fabrication process, designed to study the size dependence of the SVT properties, uses: silicon-on-insulator (SOI) wafers, a combination of ion beam and wet etching and a negative tone photoresist (SU8) as an insulating layer. The Si/Pt emitter and Si/Au collector Schottky barrier height do not depend on the transistor dimensions. The parasitic leakage current of the Si/Au collector is, however, proportional to its area. The relative collector current change with magnetic field is 240%, independent of size, while the transfer ratio starts to decrease for SVTs with an emitter area below 25 × 25 ¿m2. The maximum input current is found to be limited by the maximum current density allowed in the base (1.7 × 107 A/cm2), which is in agreement with the maximum current density for spin valve

    Geometry-coupled reactive fluid transport at the fracture scale: application to CO2 geologic storage

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    Water acidification follows CO2 injection and leads to reactive fluid transport through pores and rock fractures, with potential implications to reservoirs and wells in CO2 geologic storage and enhanced oil recovery. Kinetic rate laws for dissolution reactions in calcite and anorthite are combined with the Navier-Stokes law and advection–diffusion transport to perform geometry-coupled numerical simulations in order to study the evolution of chemical reactions, species concentration, and fracture morphology. Results are summarized as a function of two dimensionless parame- ters: the Damko€hler number Da which is the ratio between advection and reaction times, and the transverse Peclet number Pe defined as the ratio between the time for diffusion across the fracture and the time for advection along the fracture. Reactant species are readily consumed near the inlet in a carbonate reservoir when the flow velocity is low (low transverse Peclet number and Da \u3e 10-1). At high flow velocities, diffusion fails to homogenize the concentration field across the fracture (high transverse Peclet number Pe \u3e 10-1). When the reaction rate is low as in anorthite reservoirs (Da \u3c 10-1), reactant species are more readily transported toward the outlet. At a given Peclet number, a lower Damkohler number causes the flow channel to experience a more uniform aperture enlargement along the length of the fracture. When the length-to-aperture ratio is sufficiently large, say l/d \u3e 30, the system response resembles the solution for 1D reactive fluid transport. A decreased length-to-aperture ratio slows the diffusive transport of reactant species to the mineral fracture surface, and analyses of fracture networks must take into consideration both the length and slenderness of individual fractures in addition to Pe and Da numbers

    Iterative Method for Intrinsic Viscosity Measurements on Perpendicular Recording Media

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    In this paper, we introduce a new method that allows to directly measure the intrinsic viscosity (Si ) for perpendicular media using a vibrating sample magnetometer. The measurement is carried out in a number of iterations. In each iteration, the behavior of applied field (Ha) with time is gradually adjusted according to the change in the internal field (Hi) calculated from the relaxation behavior measured in the previous iteration. Eventually, during the last iteration, from which the intrinsic viscosity can be extracted, Hi is kept constant by appropriately changing Ha

    CFD Simulation of Liquid-solid Multiphase Flow in Mud Mixer

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    In the present study, a computational fluid dynamics (CFD) simulation was performed to analyze the mixing phenomena associated with multi-phase flow in a mud mixing system. For the validation of CFD simulation, firstly a liquid-solid multiphase flow inside horizontal pipe was simulated and compared with the experiments and other numerical simulations. And then, the multiphase flow simulation was carried out for the mud mixer in the drilling handling system in order to understand mixing phenomena and predict the mixing efficiency. For the modeling and simulation, a commercial software, STAR-CCM+, based on a finite-volume method (FVM) was adopted. The simulation results for liquid-solid flow inside the pipe shows a good agreement with the experimental data. With the same multiphase model, the simulation for mud mixer is performed under the generalized boundary condition and then pressure drop through the mud mixer will be discussed

    Deforming tachyon kinks and tachyon potentials

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    In this paper we investigate deformation of tachyon potentials and tachyon kink solutions. We consider the deformation of a DBI type action with gauge and tachyon fields living on D1-brane and D3-brane world-volume. We deform tachyon potentials to get other consistent tachyon potentials by using properly a deformation function depending on the gauge field components. Resolutions of singular tachyon kinks via deformation and applications of deformed tachyon potentials to scalar cosmology scenario are discussed.Comment: To appear in JHEP, 19 pages, 5 eps figures, minor changes and one reference adde

    Different fibre sources fed to weaner pigs influence production performance and acute phase protein levels

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    Dietary fibre is fermented by microbiota in the distal gastrointestinal tract (GIT) to short-chain fatty acids (SCF A). Previous studies (e.g., Pluske et al., 2002) have shown differential effects of SCF A on growth performance and the incidence of disease such as post-weaning diarrhoea (PWD), however more recently the SCF A have become recognised as potential mediators in inflammatory and immune functions in the GIT (Vinolo et al., 2011). This experiment examined the effects of infection with an enterotoxigenic strain of E. coli on pig performance, SCF A production, and biomarkers of inflammation after weaning
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