The Effect of Dietary Energy and Protein Levels on Body Condition and Production of Breeding Male Ostriches (Struthio cemelus domesticus).

In a study over two breeding seasons we assessed the effect of different energy and protein levels in the diet of male ostriches on their body weight, body condition and the fertility of the eggs produced by their females. During the first season, the birds were fed diets with energy levels of 8.5, 9.5 or 10.5 MJ metabolisable energy (ME)/kg dry matter (DM) and 13.5, 15.0 or 16.5% protein. Corresponding lysine concentrations were 6.5, 7.5 and 8.5 g/kg. In the second breeding season the groups were fed diets with energy levels of 7.5, 8.5 and 9.5 MJ ME/kg and protein levels of 10.5, 12.0 and 13.5%. Corresponding lysine concentrations were 4.9, 5.9 and 6.9 g/kg. During the first breeding season the weight of all birds increased, but the weight of those fed the 8.5 MJ ME/kg DM diet was significantly lower at the end of the season than that of birds fed diets containing 9.5 and 10.5 MJ ME/kg DM. During the second season the trend in the case of the 8.5 and 9.5 MJ ME/kg diets was the same as in the previous season, but a significant decrease in weight occurred in birds fed the 7.5 MJ ME/kg DM diet. A general loss in body condition occurred at all energy levels. In contrast, protein level in the diets had no significant effect on any parameters measured. There were no trends or significant differences in the production of fertile eggs with any of the experimental diets. We concluded from this study that levels of 8.5 MJ ME/kg DM and 10.5% protein in the diet of breeding male ostriches are sufficient if maintenance in weight is the main criteria for formulating rations

Energy-Momentum Tensor of Particles Created in an Expanding Universe

We present a general formulation of the time-dependent initial value problem for a quantum scalar field of arbitrary mass and curvature coupling in a FRW cosmological model. We introduce an adiabatic number basis which has the virtue that the divergent parts of the quantum expectation value of the energy-momentum tensor are isolated in the vacuum piece of , and may be removed using adiabatic subtraction. The resulting renormalized is conserved, independent of the cutoff, and has a physically transparent, quasiclassical form in terms of the average number of created adiabatic `particles'. By analyzing the evolution of the adiabatic particle number in de Sitter spacetime we exhibit the time structure of the particle creation process, which can be understood in terms of the time at which different momentum scales enter the horizon. A numerical scheme to compute as a function of time with arbitrary adiabatic initial states (not necessarily de Sitter invariant) is described. For minimally coupled, massless fields, at late times the renormalized goes asymptotically to the de Sitter invariant state previously found by Allen and Folacci, and not to the zero mass limit of the Bunch-Davies vacuum. If the mass m and the curvature coupling xi differ from zero, but satisfy m^2+xi R=0, the energy density and pressure of the scalar field grow linearly in cosmic time demonstrating that, at least in this case, backreaction effects become significant and cannot be neglected in de Sitter spacetime.Comment: 28 pages, Revtex, 11 embedded .ps figure

Massless Minimally Coupled Fields in De Sitter Space: O(4)-Symmetric States Versus De Sitter Invariant Vacuum

The issue of de Sitter invariance for a massless minimally coupled scalar field is revisited. Formally, it is possible to construct a de Sitter invariant state for this case provided that the zero mode of the field is quantized properly. Here we take the point of view that this state is physically acceptable, in the sense that physical observables can be computed and have a reasonable interpretation. In particular, we use this vacuum to derive a new result: that the squared difference between the field at two points along a geodesic observer's space-time path grows linearly with the observer's proper time for a quantum state that does not break de Sitter invariance. Also, we use the Hadamard formalism to compute the renormalized expectation value of the energy momentum tensor, both in the O(4) invariant states introduced by Allen and Follaci, and in the de Sitter invariant vacuum. We find that the vacuum energy density in the O(4) invariant case is larger than in the de Sitter invariant case.Comment: TUTP-92-1, to appear in Phys. Rev.

Method to compute the stress-energy tensor for the massless spin 1/2 field in a general static spherically symmetric spacetime

A method for computing the stress-energy tensor for the quantized, massless, spin 1/2 field in a general static spherically symmetric spacetime is presented. The field can be in a zero temperature state or a non-zero temperature thermal state. An expression for the full renormalized stress-energy tensor is derived. It consists of a sum of two tensors both of which are conserved. One tensor is written in terms of the modes of the quantized field and has zero trace. In most cases it must be computed numerically. The other tensor does not explicitly depend on the modes and has a trace equal to the trace anomaly. It can be used as an analytic approximation for the stress-energy tensor and is equivalent to other approximations that have been made for the stress-energy tensor of the massless spin 1/2 field in static spherically symmetric spacetimes.Comment: 34 pages, no figure

EFFECTS OF CHANGE IN BODY POSTURE ON PLASMA AND SERUM ELECTROLYTES IN NORMAL SUBJECTS AND IN PRIMARY ALDOSTERONISM

We observed that change in body posture from the supine to the erect position in normal volunteers was associated with a rise in circulating potassium and a fall in sodium concentrations, irrespective of whether the electrolytes were measured in serum or plasma, or whether head-up tilt or ambulation was used. In patients with primary aldosteronism, the fall in serum sodium and rise in serum potassium with ambulation tended to obscure the characteristic electrolyte abnormalities of that syndrome. These changes in potassium and sodium could contribute to the rise in aldosterone secretion on orthostasis. The body posture of patients should be considered in the interpretation of plasma and serum electrolyte levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75439/1/j.1365-2265.1981.tb02972.x.pd

Back to the future: using ancient Bere barley landraces for a sustainable future

Societal Impact Statement Bere is an ancient barley (Hordeum vulgare L.) that was once widely grown in northern Britain, where its ability to grow on poor soils and under challenging climatic conditions made it a valuable staple. By the end of the 20th century, Bere had largely been replaced by higher-yielding modern varieties and only survived in cultivation on a few Scottish islands. This article reviews the recent revival of Bere, driven by its use in high-value food and drink products and multidisciplinary research into its genetics, valuable sustainability traits and potential for developing resilient barley varieties. Summary In Britain, modern cereal varieties have mostly replaced landraces. A remarkable exception occurs on several Scottish islands where Bere, an ancient 6-row barley (Hordeum vulgare L.), is grown as a monocrop or in mixtures. In the Outer Hebrides, the mixture is grown for animal feed, and cultivating it with traditional practices is integral to the conservation of Machair, an important coastal dune ecosystem. In Orkney, Bere is grown as a monocrop, and in situ conservation has recently been strengthened by improved agronomy and new markets for grain to produce unique foods and beverages from beremeal (flour) and malt. In parallel, a recently assembled collection of British and North European barley landraces has allowed the genotypic and phenotypic characterisation of Bere and several associated multidisciplinary studies. Genotyping demonstrated Bere's unique identity compared with most other barleys in the collection, indicating an earlier introduction to Scotland than the Norse settlement (c. 9th century AD) suggested previously. Valuable traits found in some Bere accessions include disease resistance, an early heading date (reflecting a short period from sowing to harvest), the ability to grow on marginal, high pH soils deficient in manganese and tolerance to salinity stress. These traits would have been important in the past for grain production under the region's challenging soil and Atlantic-maritime climatic conditions. We discuss these results within the context of Bere as a genetic, heritage and commercial resource and as a future source of sustainability traits for barley improvement

High-Energy Aspects of Solar Flares: Overview of the Volume

In this introductory chapter, we provide a brief summary of the successes and remaining challenges in understanding the solar flare phenomenon and its attendant implications for particle acceleration mechanisms in astrophysical plasmas. We also provide a brief overview of the contents of the other chapters in this volume, with particular reference to the well-observed flare of 2002 July 23Comment: This is the introductory article for a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

The effects of counterion exchange on charge stabilization for anionic surfactants in nonpolar solvents.

HYPOTHESIS: Sodium dioctylsulfosuccinate (Aerosol OT or NaAOT) is a well-studied charging agent for model poly(methyl methacrylate) (PMMA) latexes dispersed in nonpolar alkane solvents. Despite this, few controlled variations have been made to the molecular structure. A series of counterion-exchanged analogs of NaAOT with other alkali metals (lithium, potassium, rubidium, and cesium) were prepared, and it was expected that this should influence the stabilization of charge on PMMA latexes and the properties of the inverse micelles. EXPERIMENTS: The electrophoretic mobilities of PMMA latexes were measured for all the counterion-exchanged AOT analogs, and these values were used to calculate the electrokinetic or ζ potentials. This enabled a comparison of the efficacy of the different surfactants as charging agents. Small-angle scattering measurements (using neutrons and X-rays) were performed to determine the structure of the inverse micelles, and electrical conductivity measurements were performed to determine the ionized fractions and Debye lengths. FINDINGS: Sodium AOT is a much more effective charging agent than any of the other alkali metal AOTs. Despite this, the inverse micelle size and electrical conductivity of NaAOT are unremarkable. This shows a significant non-periodicity in the charging efficiency of these surfactants, and it emphasizes that charging particles in nonpolar solvents is a complex phenomenon