Comunicación corta. Aflatoxina y ochratoxina A totales en hígado, riñones y plasma de pollos contaminados experimentalmente

Mycotoxicosis, particularly that caused by aflatoxins and ochratoxins, is a serious problem for the poultry production industry. The aim of this study was to determine the total aflatoxin and ochratoxin A levels in liver and plasma, and kidneys and plasma, respectively, of chickens for fattening fed experimentally contaminated diets, and to assess the impact of these toxins on body weight increase and the feed conversion ratio (FCR). Forty eight 21 day-old Ross breeder chickens (n = 12 x four treatments) were fed diets containing different levels of mycotoxins: grower diet + ochratoxin A (200 mg/kg of feed) + total aflatoxin in different concentrations (T1 = 60 microg/kg of feed; T = 50 microg/kg; T3 = 30 microg/kg). Control chickens (T4) were fed only the grower diet. No significant differences were seen in the weight increase of chickens subjected to the different treatments. However, lower FCRs were seen in those exposed to T1 and T2. In general, the amount of total aflatoxin and ochratoxin A found in the liver, kidneys and plasma (determined by ELISA) were directly related to the amounts added to the experimental diets and feed consumption. Plasma ochratoxin A was always higher than kidney levels; this relationship was not seen for total aflatoxin.Las micotoxicosis, en particular las aflatoxicosis y ocratoxicosis, son un serio problema sanitario en la producción avícola. El objetivo de este trabajo fue determinar el nivel de aflatoxinas y ochratoxinas A en hígado y plasma, y riñones y plasma, respectivamente, de pollos alimentados con dietas experimentalmente contaminadas e investigar el impacto de estas toxinas en el peso corporal y el cociente de conversión del alimento (FCR). Se alimentaron 48 pollos Ross de 21 días de edad (n = 12 x cuatro tratamientos) con dietas conteniendo diferentes niveles de micotoxinas: una dieta de crecimiento + 200 mg/kg de ochratoxina A + aflatoxina total en diferentes concentraciones (T1 = 60 microg/kg; T2 = 50 microg/kg; T3 = 30 microg/kg). Lo pollos control (T4) fueron solamente alimentados con la dieta de engorde. No hubo diferencias significativas en el aumento de peso de los pollos sometidos a los diferentes tratamientos; sin embargo, se detectaron FCRs menores para los expuestos a T1 y T2. En general, la cantidad de aflatoxina total y ochratoxina A detectadas por ELISA en hígado, riñones y plasma fueron directamente proporcionales a los niveles de las micotoxinas añadidas a las dietas experimentales. La ochratoxina A en plasma fue siempre superior a la encontrada en riñón; esta relación no se detectó para la aflatoxina total

Dissipative Abelian Sandpiles and Random Walks

We show that the dissipative Abelian sandpile on a graph L can be related to a random walk on a graph which consists of L extended with a trapping site. From this relation it can be shown, using exact results and a scaling assumption, that the dissipative sandpiles' correlation length exponent \nu always equals 1/d_w, where d_w is the fractal dimension of the random walker. This leads to a new understanding of the known results that \nu=1/2 on any Euclidean lattice. Our result is however more general and as an example we also present exact data for finite Sierpinski gaskets which fully confirm our predictions.Comment: 10 pages, 1 figur

Instanton Effects in QCD at High Baryon Density

We study instanton effects in QCD at very high baryon density. In this regime instantons are suppressed by a large power of $(\Lambda_{QCD}/\mu)$, where $\Lambda_{QCD}$ is the QCD scale parameter and $\mu$ is the baryon chemical potential. Instantons are nevertheless important because they contribute to several physical observables that vanish to all orders in perturbative QCD. We study, in particular, the chiral condensate and its contribution $m_{GB}^2\sim m$ to the masses of Goldstone bosons in the CFL phase of QCD with $N_f=3$ flavors. We find that at densities $\rho\sim (5-10) \rho_0$, where $\rho_0$ is the density of nuclear matter, the result is dominated by large instantons and subject to considerable uncertainties. We suggest that these uncertainties can be addressed using lattice calculations of the instanton density and the pseudoscalar diquark mass in QCD with two colors. We study the topological susceptibility and Witten-Veneziano type mass relations in both $N_c=2$ and $N_c=3$ QCD.Comment: 27 pages, 8 figures, minor revision

A New Relativistic High Temperature Bose-Einstein Condensation

We discuss the properties of an ideal relativistic gas of events possessing Bose-Einstein statistics. We find that the mass spectrum of such a system is bounded by $\mu \leq m\leq 2M/\mu _K,$ where $\mu$ is the usual chemical potential, $M$ is an intrinsic dimensional scale parameter for the motion of an event in space-time, and $\mu _K$ is an additional mass potential of the ensemble. For the system including both particles and antiparticles, with nonzero chemical potential $\mu ,$ the mass spectrum is shown to be bounded by $|\mu |\leq m\leq 2M/\mu _K,$ and a special type of high-temperature Bose-Einstein condensation can occur. We study this Bose-Einstein condensation, and show that it corresponds to a phase transition from the sector of continuous relativistic mass distributions to a sector in which the boson mass distribution becomes sharp at a definite mass $M/\mu _K.$ This phenomenon provides a mechanism for the mass distribution of the particles to be sharp at some definite value.Comment: Latex, 22 page

On the choice of heavy baryon currents in the relativistic three-quark model

We test the sensitivity of bottom baryon observables with regard to the choice of the interpolating three-quark currents within the relativistic three-quark model. We have found that the semileptonic decay rates are clearly affected by the choice of currents, whereas the asymmetry parameters show only a very weak dependence on the choice of current.Comment: revtex, 9 page