Lamb Stocking, Grazing System and Supplementation Effects on Triticale and Ryegrass Swards Performance in Uruguay

An experiment was carried out from 3 of July to 22 of October 1998, using a Lolium multiflorum Lom. (ryegrass) and Triticosecale Wittmack (triticale) sward grazed by lambs, to examine the effect of stocking rate (SR; 25 and 35 lambs/ha), grazing system (GS; strip and 7 days rotational grazing) and supplementation (S; with or without) on sward structure, production, composition and nutritive value. SR affected significantly pre and post grazing herbage mass and sward height, being higher at the lower SR (3211 vs 2832 kg DM ha-1, P \u3c 0.01; 2443 vs 1939 kg DM ha-1, P \u3c 0.01; 19 vs 17 cm, P \u3c 0.01 and 10 vs 8 cm, P \u3c 0.01 respectively), increasing, at the high SR, the proportions of the ryegrass green leaf component, particularly in the uppermost layers of the sward canopy. In comparison with 7 days rotational GS, strip GS resulted in higher post grazing herbage mass, sward height and nutritive value (2387 vs 1996 DM ha-1, P \u3c 0.01; 10 vs 9 cm, P \u3c 0.01; 62 vs 67 % NDF, P \u3c 0.01 and 33 vs 37 % ADF, P \u3c 0.01). S increased post grazing herbage mass and sward height (2347 vs 2035 DM ha-1, P \u3c 0.01 and 10 vs 9 cm, P \u3c 0.01). This experiment showed the high forage productive potential and nutritive value of ryegrass and triticale swards for lamb production in the sandy soil region of Uruguay and the dominant effect of SR on swards variables comparing with GS and S

Chaplygin gas with non-adiabatic pressure perturbations

Perturbations in a Chaplygin gas, characterized by an equation of state $p = -A/\rho$, may acquire non-adiabatic contributions if spatial variations of the parameter $A$ are admitted. This feature is shown to be related to a specific internal structure of the Chaplygin gas. We investigate how perturbations of this type modify the adiabatic sound speed and influence the time dependence of the gravitational potential which gives rise to the Integrated Sachs-Wolfe effect in the anisotropy spectrum of the cosmic microwave background.Comment: 16 pages, comments and references added, accepted for publication in Class.Quantum Gra

Quantificação de NBA?s provenientes da digestão ácida de materiais biológicos assistida por radiação micro-ondas.

O emprego de ácidos diluídos é uma alternativa viável para solubilização de materiais biológicos utilizando digestão assistida por radiação micro-ondas para a análise elementar por técnicas espectroanalíticas1. Como produtos de decomposição, vários compostos orgânicos foram descritos na literatura, sendo que os isômeros do ácido nitrobenzóico (NBA) são os mais citados quando amostras com elevados teores de proteína são digeridas2. Os mecanismos de digestão podem ser propostos através da predominância de um ou outro isômero. O ácido nitrobenzóico (NBA) é um nitroaromático e possui 3 isômeros de posição, sendo estes: o-, m-, p-NBA3. O objetivo deste trabalho foi investigar as variáveis significativas durante a etapa de extração desses 3 isômeros em amostras digeridas com diferentes concentrações ácidas e diferentes composições químicas, para posterior quantificação por métodos cromatográficos

Hard Thermal Loops, Static Response and the Composite Effective Action

First, we investigate the static non-Abelian Kubo equation. We prove that it does not possess finite energy solutions; thereby we establish that gauge theories do not support hard thermal solitons. A similar argument shows that "static" instantons are absent. In addition, we note that the static equations reproduce the expected screening of the non-Abelian electric field by a gauge invariant Debye mass m=gT sqrt((N+N_F/2)/3). Second, we derive the non-Abelian Kubo equation from the composite effective action. This is achieved by showing that the requirement of stationarity of the composite effective action is equivalent, within a kinematical approximation scheme, to the condition of gauge invariance for the generating functional of hard thermal loops.Comment: 17 pages, MIT preprint CTP#2261. An Appendix [including one (appended) PS figure] presenting a numerical analysis of the static solutions has been included. A note relating our approach to alternative ones has been added. We have also added references and comments in Section II

Exact Histogram Specification Optimized for Structural Similarity

An exact histogram specification (EHS) method modifies its input image to have a specified histogram. Applications of EHS include image (contrast) enhancement (e.g., by histogram equalization) and histogram watermarking. Performing EHS on an image, however, reduces its visual quality. Starting from the output of a generic EHS method, we maximize the structural similarity index (SSIM) between the original image (before EHS) and the result of EHS iteratively. Essential in this process is the computationally simple and accurate formula we derive for SSIM gradient. As it is based on gradient ascent, the proposed EHS always converges. Experimental results confirm that while obtaining the histogram exactly as specified, the proposed method invariably outperforms the existing methods in terms of visual quality of the result. The computational complexity of the proposed method is shown to be of the same order as that of the existing methods. Index terms: histogram modification, histogram equalization, optimization for perceptual visual quality, structural similarity gradient ascent, histogram watermarking, contrast enhancement

Hard Thermal Loops, Gauged WZNW Action and the Energy of Hot Quark-Gluon Plasma

The generating functional for hard thermal loops in QCD is rewritten in terms of a gauged WZNW action by introducing an auxiliary field. This shows in a simple way that the contribution of hard thermal loops to the energy of the quark-gluon plasma is positive.Comment: 9 pages, CU-TP 60

Detecting the (Quasi-)Two-Body Decays of τ\tau Leptons in Short-Baseline Neutrino Oscillation Experiments

Novel detector schemes are proposed for the short-baseline neutrino experiments of next generation, aimed at exploring the large-$\Delta m^2$ domain of \omutau oscillations in the appearance mode. These schemes emphasize good spectrometry for charged particles and for electromagnetic showers and efficient reconstruction of \ypi_gg decays. The basic elements are a sequence of relatively thin emulsion targets, immersed in magnetic field and interspersed with electronic trackers, and a fine-grained electromagnetic calorimeter built of lead glass. These elements act as an integral whole in reconstructing the electromagnetic showers. This conceptual scheme shows good performance in identifying the $\tau$ (quasi-)two-body decays by their characteristic kinematics and in selecting the electronic decays of the $\tau$.Comment: 34 pages, 8 figure