Spin dependent D-brane interactions and scattering amplitudes in matrix theory

Spin interactions beteween two moving Dp-branes are analyzed using the Green-Schwarz formalism of boundary states. This approach turns out to be extremely efficient to compute all the spin effects related by supersymmetry to the leading v^4/r^7-p term. All these terms are shown to be scale invariant, supporting a matrix model description of supergravity interactions. By employing the LSZ reduction formula for matrix theory and the mentioned supersymmetric effective potential for D0-branes, we compute the t-pole of graviton-graviton and three form-three form scattering in matrix theory. The results are found to be in complete agreement with tree level supergravity in the corresponding kinematical regime and provide, moreover, an explicit map between these degrees of freedom in both theories.Comment: 8 pages, no figures, talk presented at the conference "Quantum aspects of gauge theories, supergravity and unification", Corfu, Greece, to appear in the proceeding

Extensions of discrete classical orthogonal polynomials beyond the orthogonality

It is well known that the family of Hahn polynomials $\{h_n^{\alpha,\beta}(x;N)\}_{n\ge 0}$ is orthogonal with respect to a certain weight function up to $N$. In this paper we present a factorization for Hahn polynomials for a degree higher than $N$ and we prove that these polynomials can be characterized by a $\Delta$-Sobolev orthogonality. We also present an analogous result for dual-Hahn, Krawtchouk, and Racah polynomials and give the limit relations between them for all n\in \XX N_0. Furthermore, in order to get this results for the Krawtchouk polynomials we will get a more general property of orthogonality for Meixner polynomials.Comment: 2 figures, 20 page

Ileum and whole-tract digestibility of carbohydrates contained in a corn- or a sorghum-acorn-based diets fed on finishing Landrace and Iberian pigs

Starch is the storage polysaccharide of higher plants and a major source for animals. However, despite is its simple composition the digestion of starch may be dependent of feed ingredients and animal characteristics

An increased hindgut fermentation promoted major changes on the VFA profile but not on the total VFA concetration of the digesta contents

Volatile fatty acids, principally acetate, propionate and butyrate, are produced in the caecum-colon of pigs as end products of the microbial fermentation. The present abstract tryes to explore on the changes on the VFA concentration and profiles observed in Landrace and Iberian pigs fed on different sources of carbohydrates (high v. low digestible starch)

Effect of the Heart Rate Variability Representations on the Quantification of the Cardiorespiratory Interactions during Autonomic Nervous System Blockade

The Heart Rate Variability (HRV) is a noninvasive tool to evaluate the activity of the autonomic nervous system. To study the HRV, different mathematical representations can be used. The selection of a representation might have an effect on the evaluation of the mechanisms that modulate the Heart Rate (HR). One of these mechanisms is the Respiratory Sinus Arrhythmia (RSA), i.e. an increased HR during inhalation and a decreased HR during exhalation. Different methods exist to quantify the RSA. A common approach is to calculate the power in the High Frequency (HF, 0.15 - 0.4 Hz) band of the spectrum of the HRV representation. More recently proposed methods use the respiratory signals to estimate the strength of the RSA.This paper studies the effect of the HRV representations on the quantification of the RSA. To this end, an experiment is used in which the sympathetic and parasympathetic branches of the autonomic nervous system are selectively blocked. Three different HRV representations are considered. Afterwards, the strength of the RSA is estimated using three approaches, namely the spectral content in the HF band of the HRV representations, orthogonal subspace projections and a time-frequency representation.The results suggest that the selection of an HRV representation does not have a significant impact on the RSA estimates in a healthy population

Bound States of Type I D-Strings

We study the infra-red limit of the O(N) gauge theory that describes the low energy modes of a system of $N$ type I D-strings and provide some support to the conjecture that, in this limit, the theory flows to an orbifold conformal theory. We compute the elliptic genus of the orbifold theory and argue that its longest string sector describes the bound states of D-strings. We show that, as a result, the masses and multiplicities of the bound states are in agreement with the predictions of heterotic-type I duality in 9 dimensions, for all the BPS charges in the lattice $\Gamma_{(1,17)}$.Comment: 14 pages, (AMS-)LaTex file using amstex.st

Comparative digestibility and productive performances between Landrace and Iberian pigs fed on a corn- or a sorghum-acorn- based diet

Although digestible energy (DE) values for most commonly used feeds in pig industry are mainly predicted by their chemical composition, other likely effects could affect digestibility. The present paper try to explore the effects likely caused by animal breed (lean v. fat line) and dietary ingredients used

Body fat content, composition and distribution in Landrace and Iberian finishing pigs given ad libitum maize- and acorn-sorghummaize-based diets

We aimed to determine whether the dietary carbohydrate source altered body fat composition and distribution in finishing lean (Landrace) and obese (Iberian) swine. To this end, twenty-four finishing castrated male pigs (12 Iberian and 12 Landrace; 108 kg live weight) were offered two diets differing in the main carbohydrates source, maize (diet M) or acorn-sorghum-maize (diet A). Diets were formulated to have the same nutrient content, except for carbohydrate fractions : diet M contained higher amount of starch (537 v.389 g/kg) but less non-starchpolysaccharides (118 v.148 g/ kg) than diet A. At an average weight of 133 kg live weight pigs were slaughtered and their carcasses were sampled to study lipogenesis, backfat and intramuscular fat composition. Iberian pigs showed a higher voluntary food intake than Landrace pigs (3•6 v.2•4 kg/day; P< 0•001) but no significant differences in the daily weight gain. Diet M tended to promote the highest food intake (P= 0•09). Iberian pigs showed higher (P< 0•01) lipogenic enzyme activities, backfat thickness (71•7v.31•9 mm) and intramuscular fat content (40 to 95 g/kg fresh muscle) than Landrace pigs, which was associated with their higher food intake. Furthermore, fat depots from Iberian pigs had higher (P< 0•001) monounsaturated fatty acids (MUFA) and lower (P< 0•05) polyunsaturated (PUFA) proportions than those from Landrace pigs. The backfat thickness of pigs given diet M tended to be higher (P= 0•07) than that of pigs given diet A, without differences in the intramuscular fat content. The higher backfat thickness found for diet M was correlated with a lower PUFA proportion in diet than for diet A (P< 0•001). we conclude that body fat content, composition and lipogenic enzyme activities are markedly influenced by the animal breed and to a lesser extent by dietary characteristics

On the spectrum of AdS/CFT beyond supergravity

We test the spectrum of string theory on AdS_5 x S^5 derived in hep-th/0305052 against that of single-trace gauge invariant operators in free N=4 super Yang-Mills theory. Masses of string excitations at critical tension are derived by extrapolating plane-wave frequencies at g_{YM}=0 down to finite J. On the SYM side, we present a systematic description of the spectrum of single-trace operators and its reduction to PSU(2,2|4) superconformal primaries via a refined Eratostenes' supersieve. We perform the comparison of the resulting SYM/string spectra of charges and multiplicities order by order in the conformal dimension \Delta up to \Delta=10 and find perfect agreement. Interestingly, the SYM/string massive spectrum exhibits a hidden symmetry structure larger than expected, with bosonic subgroup SO(10,2) and thirty-two supercharges.Comment: 28 pages, LaTeX2

Lipogenic enzyme activities in adipose and muscular tissues of Landrace and Iberian pigs fed on different source of carbohydrates

Iberian is an autochthonous swine breed from Southwest Iberian Peninsula. His meat has attained a high acceptability attributed to a higher intramuscular fat. Gene and dietary effects on the lipogenic enzymes activities were evaluated