Studies in physiological undernourishment in sheep

1. An examination of changes in weight and body composition in a flock of free -grazing Scottish Blackface ewes indicated that, during the greater part of pregnancy, these ewes were undernourished and catabolizing considerable amounts of body tissue.2. The nutritional states of ewes from two differently managed Scottish Blackface flocks were characterized during late pregnancy in terms of circulating concentrations of plasma free fatty acids and ketones. Marked undernourishment was evident in both situations.3. Data collected in a variety of situations supported the hypothesis that the severity of undernourishment during late pregnancy is determined principally by foetal weight and the level of food intake. Within a group of pregnant ewes with comparable intakes, the general degree of undernourishment is dependent on the level of intake, and the relative severity of undernourishment in individual animals is determined by differences in foetal weight.4. The use of certain biochemical parameters as indices of undernourishment was examined in ewes with artificially induced hypoglycaemia. It was concluded that nutritional state is best characterized in terms of that parameter which shows the greatest response per unit change in either nutrient intake or nutrient requirement.5. Biochemical parameters were used to control the nutritional states of individual animals in an experiment on the effects of undernourishment during pregnancy on lamb birth- weight. The results of this experiment indicated that the undernourishment occurring in free- grazing hill ewes during late pregnancy was likely to reduce the birth - weight of single lambs by 10%, and that of twins by 25%.6. The additional energy requirements during pregnancy were estimated to be 100g digestible organic matter per kg foetus

Some aspects of the bone-muscle relationships in New Zealand lamb and mutton carcasses : a thesis presented at Massey Agricultural College in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand

Best copy available.The three main constituents of a meat carcass are bone, musele, and fat, and of these the lean meat or muscle is of greatest interest and importance to the consumer. Bone represents an almost total waste and is hence considered as undesizable and as something which must be accepted with the desirable muscular tissue. In the words of Robert Bakewell, "You can't eat bone, therefore give the public something to eat." (Dawson, 1957). The Physical properties of muscle and bone are markedly different. Muscular tissue is compressible and hence difficult to ensure with accuracy on a linear scale. The intimate association of skeletal muscle with other tissues makes its complete removal for accurate weight estimation both difficult and tedious. Bony tissue, on the other hand, lends itself more readily to the measurement of linear dimensions and weight

Viscoelasticity of two-layer-vesicles in solution

The dynamic shape relaxation of the two-layer-vesicle is calculated. In additional to the undulation relaxation where the two bilayers move in the same direction, the squeezing mode appears when the gap between the two bilayers is small. At large gap, the inner vesicle relaxes much faster, whereas the slow mode is mainly due to the outer layer relaxation. We have calculated the viscoelasticity of the dilute two-layer-vesicle suspension. It is found that for small gap, the applied shear drives the undulation mode strongly while the slow squeezing mode is not much excited. In this limit the complex viscosity is dominated by the fast mode contribution. On the other hand, the slow mode is strongly driven by shear for larger gap. We have determined the crossover gap which depends on the interaction between the two bilayers. For a series of samples where the gap is changed systematically, it is possible to observe the two amplitude switchings

Anomalous wave reflection from the interface of two strongly nonlinear granular media

Granular materials exhibit a strongly nonlinear behaviour affecting the propagation of information in the medium. Dynamically self-organized strongly nonlinear solitary waves are the main information carriers in granular chains. Here we report the first experimental observation of the dramatic change of reflectivity from the interface of two granular media triggered by a noncontact magnetically induced initial precompression. It may be appropriate to name this phenomenon the "acoustic diode" effect. Based on numerical simulations, we explain this effect by the high gradient of particle velocity near the interface.Comment: 14 pages, 3 figure

QCD Corrections to Production of Higgs Pseudoscalars

Models of electroweak symmetry breaking with more than a single doublet of Higgs scalars contain a neutral pseudoscalar boson. The production of such a pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a top-quark loop (except for those models in which the pseudoscalar coupling to bottom quarks is strongly enhanced). We compute the QCD corrections to this process in the heavy-quark limit, using an effective Lagrangian derived from the axial anomaly.Comment: 9 pages, (BNL number added, 1 typo corrected, PHYZZX format, 4 figures not included, available on request), BNL-4906

Very Low Mass Stars and Brown Dwarfs in Taurus-Auriga

We present high resolution optical spectra obtained with the HIRES spectrograph on the Keck I telescope of low mass T Tauri stars and brown dwarfs (LMTTs) in Taurus-Auriga. Of particular interest is the previously classified "continuum T Tauri star" GM Tau, which has a spectral type of M6.5 and a mass just below the stellar/substellar boundary. None of the LMTTs in Taurus are rapidly rotating (vsini < 30 km/s), unlike low mass objects in Orion. Many of the slowly rotating, non-accreting stars and brown dwarfs exhibit prominent H-alpha emission (EWs of 3 - 36 A), indicative of active chromospheres. We demonstrate empirically that the full-width at 10% of the H-alpha emission profile peak is a more practical and possibly more accurate indicator of accretion than either the equivalent width of H-alpha or optical veiling: 10%-widths > 270 km/s are classical T Tauri stars (i.e. accreting), independent of stellar spectral type. Although LMTTs can have accretion rates comparable to that of more typical, higher-mass T Tauri stars (e.g. K7-M0), the average mass accretion rate appears to decrease with decreasing mass. The diminished frequency of accretion disks for LMTTs, in conjunction with their lower, on average, mass accretion rates, implies that they are formed with less massive disks than higher-mass T Tauri stars. The radial velocities, circumstellar properties and known binaries do not support the suggestion that many of the lowest mass members of Taurus have been ejected from higher stellar density regions within the cloud. Instead, LMTTs appear to have formed and are evolving in the same way as higher-mass T Tauri stars, but with smaller disks and shorter disk lifetimes.Comment: 27 pages, plus 8 figures, accepted for publication in Ap

Entropic phase separation of linked beads

We study theoretically a model system of a transient network of microemulsion droplets connected by telechelic polymers and explain recent experimental findings. Despite the absence of any specific interactions between either the droplets or polymer chains, we predict that as the number of polymers per drop is increased, the system undergoes a first order phase separation into a dense, highly connected phase, in equilibrium with dilute droplets, decorated by polymer loops. The phase transition is purely entropic and is driven by the interplay between the translational entropy of the drops and the configurational entropy of the polymer connections between them. Because it is dominated by entropic effects, the phase separation mechanism of the system is extremely robust and does not depend on the particlular physical realization of the network. The discussed model applies as well to other polymer linked particle aggregates, such as nano-particles connected with short DNA linkers

Simulation of Claylike Colloids

We investigate properties of dense suspensions and sediments of small spherical silt particles by means of a combined Molecular Dynamics (MD) and Stochastic Rotation Dynamics (SRD) simulation. We include van der Waals and effective electrostatic interactions between the colloidal particles, as well as Brownian motion and hydrodynamic interactions which are calculated in the SRD-part. We present the simulation technique and first results. We have measured velocity distributions, diffusion coefficients, sedimentation velocity, spatial correlation functions and we have explored the phase diagram depending on the parameters of the potentials and on the volume fraction.Comment: 20 pages, 14 figure

Liquid-liquid equilibrium for monodisperse spherical particles

A system of identical particles interacting through an isotropic potential that allows for two preferred interparticle distances is numerically studied. When the parameters of the interaction potential are adequately chosen, the system exhibits coexistence between two different liquid phases (in addition to the usual liquid-gas coexistence). It is shown that this coexistence can occur at equilibrium, namely, in the region where the liquid is thermodynamically stable.Comment: 6 pages, 8 figures. Published versio