898 research outputs found
On the Relation between Eulerian and Lagrangian Averages in the Statistical Theory of Turbulence
Only severe gastric ulcers reduce performance in growing-finishing pigs
Ulceration in the pars oesophageal region of the stomach of pigs is frequently registered at slaughter. Pigs with gastric lesions are reported to have lowered productivity (Ayles et al., 1996), but other studies have found no significant effects on performance (Guise et al., 1997). The objective of this study was to quantify the correlation between ulcer severity and growth performance in growing-finishing pigs
Performance and gastric ulcers in growing-finishing pigs fed alfalfa hay meal or a coarse-milled pelleted diet
Danish producers using pelleted feed and experiencing problems with gastric ulcers in their herd are sometimes advised to use diets containing alfalfa hay meal or diets that have greater mean particle size. However the effects of such interventions have not fully been investigated. These experiments investigated the effect of alfalfa hay meal and coarser milling in pelleted diets on growth performance and occurrence of gastric ulcers in growing-finishing pigs
Analyzing standard curves in the chemistry of waters used for aquaculture
A practical guide is given to help aquaculture researchers identify and correct common problems associated with the colorimetric analysis of water. Hints in making standard solutions, choosing standard concentrations for making a standard curve and making measurements are included. Various types of standard curves and some problems are outlined and details provided regarding the evaluation of standard curves
Analyzing standard curves in the chemistry of waters used for aquaculture
Water analysis, Colorimetric techniques, Analytical techniques, Aquaculture
Estrogen Receptor-α Populations Change with Age in Commercial Laying Hens
Older hens in production lay larger but fewer eggs than younger birds, and the incidence of soft and broken shells is greater in older hens than younger. These changes are attributable at least in part to changing hormone profiles and diminished ability of the hen to transport calcium at the duodenum. In further exploration of this relationship, a study was conducted with three ages of Hy-Line W-36 birds: prelay pullets (PL; 19 wk, 0% production), peak-production hens (PP; 29 wk, ∼93% production), and late-stage hens (LS; 71 wk, ∼80% production). Hens from the PP and LS groups were palpated for presence of an egg in the shell gland; hens were then euthanized and tissues (kidney, shell gland, hypothalamus) were removed for quantification of estrogen receptor- α (ERα) populations via immunocytochemical and Western blot analyses. Localization of ERα by immunostaining in the shell gland showed differences among age groups; however, no differences were noted in localization of ERα between age groups in the kidney and hypothalamus. In both the kidney and the shell gland there was a decrease in the amount of ERα, as detected by immunoblotting, in the LS hens compared to PL and PP birds (P \u3c 0.05). The results suggest that failure of calcium regulating mechanisms with age may be mediated at least in part through the reduced populations of estrogen receptors in certain critical tissues
Separate and combined effects of oligofructose and inulin on post-weaning coli bacillosis and weight gain: a preliminary study
Trends for a reduction in the use of dietary antibiotic growth promoters have caused increased interest in the use of alternative feed additives to maintain 'gut health' after weaning. Oligofructose and inulin are 'prebiotic' fructan-containing carbohydrates purported to enhance 'gut health' in newly-weaned pigs by altering microbial diversity (Konstantinov, et al., 2003). However, their effects using a challenge model of post-weaning colibacillosis (PWC) have never been examined. The aim of the present study was to compare the separate and combined effects of oligofructose and inulin supplementation on the occurrence of diarrhoea and the weight performance in piglets experimentally challenged with enterotoxigenic E. coli (ETEC)
Particle size and form of the diet influence production and gastric health in growing-finishing pigs
Under Danish conditions, pelleted diets increase performance in growing-finishing pigs but compromise gastric health compared with coarsely-ground meal-feed (Hansen, 2004). However, in these studies the particle size of the mealfeed was coarser than commercial practice, and consequencly it is not known if pelleted feed increases performance compared with meal-feed or if differences were attributable to particle size effects. The aim of this study was to investigate the effect of feed grinding and pelleting on performance and gastric health in growing-finishing pigs
Simple Fluids with Complex Phase Behavior
We find that a system of particles interacting through a simple isotropic
potential with a softened core is able to exhibit a rich phase behavior
including: a liquid-liquid phase transition in the supercooled phase, as has
been suggested for water; a gas-liquid-liquid triple point; a freezing line
with anomalous reentrant behavior. The essential ingredient leading to these
features resides in that the potential investigated gives origin to two
effective core radii.Comment: 7 pages including 3 eps figures + 1 jpeg figur
Towards a Simple Model of Compressible Alfvenic Turbulence
A simple model collisionless, dissipative, compressible MHD (Alfvenic)
turbulence in a magnetized system is investigated. In contrast to more familiar
paradigms of turbulence, dissipation arises from Landau damping, enters via
nonlinearity, and is distributed over all scales. The theory predicts that two
different regimes or phases of turbulence are possible, depending on the ratio
of steepening to damping coefficient (m_1/m_2). For strong damping
(|m_1/m_2|<1), a regime of smooth, hydrodynamic turbulence is predicted. For
|m_1/m_2|>1, steady state turbulence does not exist in the hydrodynamic limit.
Rather, spikey, small scale structure is predicted.Comment: 6 pages, one figure, REVTeX; this version to be published in PRE. For
related papers, see http://sdphpd.ucsd.edu/~medvedev/papers.htm
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