Eficacia de un desinfectante sobre Vibrio ordalii, Vibrio anguillarum, Francisella sp. y Virus de la Necrosis Pancreática Infecciosa (IPNV), patógenos de salmón del Atlántico (Salmo salar) cultivado en Chile

Indexación: ScieloRESUMEN En el presente trabajo se evaluó la eficacia in vitro del desinfectante Duplalim®, una combinación sinérgica de glutaraldehído y sales de amonio cuaternario de cuarta generación, contra 4 patógenos de peces prevalentes de la salmonicultura chilena. Los resultados muestran que todas las concentraciones ensayadas (diluciones entre 1:200 a 1:400) fueron eficaces sobre los aislados de Vibrio ordalii y Vibrio anguillarum post-30 s de exposición, detectando niveles de reducción igual a 1.8 x 106 UFC/ml. Concentraciones superiores de Duplalim® (dilución 1:50) y un tiempo de exposición no menor a 5 min. Fueron necesarios para eliminar completamente al patógeno intracelular Francisella sp. Cuando el desinfectante fue ensayado contra el Virus de la necrosis Pancreática infecciosa (IPNV), se detectó que la dilución 1:400 tiene un efecto significativo después de 2 minutos sin importar los títulos de IPNV testeados (mayor concentración evaluada 107.6 TCID50/ml). Duplalim® se evaluó en condiciones masivas contra los miembros de la familia Vibrionaceae. En comparación a los controles (sin adición desinfectante), la dilución 1:400 de Duplalim® eliminó completamente V. ordalii y V. anguillarum después de 15 minutos de tratamiento, tanto en el agua de cultivo como en la superficie de mallas usadas en el cultivo del salmón. Así, el análisis microbiológico del agua de los controles mostró concentraciones de 1.4 ± 0.3 × 106 UFC/ml, mientras en el caso de las mallas 7.6 ± 3.2 × 105 UFC/ml1. En resumen, los antecedentes obtenidos indican que el uso del desinfectante Duplalim® es efectivo contra V. ordalii, V. anguillarum y IPNV en bajas concentraciones y cortos periodos de exposición (dilución 1:400 por 15 min.), mientras que para el patógeno intracelular se requiere una concentración mayor. Palabras clave: desinfectante, patógenos de peces, salmón del atlántico. SUMMARY The efficacy of the disinfectant Duplalim®, a synergistic blend of superquats and glutaraldehyde, was analysed in vitro against 4 fish pathogens. All concentrations tested (1:200 to 1:400 dilutions) were efficacious on killing Vibrio ordalii and Vibrio anguillarum in seawater after 30 s, being the level of reduction equal to 1.8 x 106 CFU/ml. Higher concentration of Duplalim® (1:50 dilutions) and time of exposure (at least 5 min) is needed to kill completely Francisella sp, an intracellular freshwater pathogen. When Infectious Pancreatic Necrosis Virus (IPNV) was treated with 1:400 disinfectant dilution, this concentration had a significant effect after 2 minutes, regardless of the IPNV titres employed (concentration greater than 107.6 TCID50/ml). Duplalim® was tested in large scale against Vibrionaceae members. In comparison to the controls (without the disinfectant), 1:400 dilutions of Duplalim® totally killed V. ordalii and V. anguillarum in seawater as well as on the surface of the fishing net (used in the cages of cultured salmon) after 15 min. Cultivable bacteria remained constant in the buckets without the disinfectant (1.4 ± 0.3 × 106 CFU/ml), regardless of the period sampled. In the case of the adherence on the fishing net, bacteria not exposed to the disinfectant were detected at a concentration of 7.6 ± 3.2 × 105 CFU/ml. These data indicate that the use of Duplalim® against V. ordalii, V. anguillarum and IPNV is effective in low concentration and short time of exposure (15 min at a concentration of 1:400 dilutions), while the intracellular pathogen requires higher concentration. Key words: disinfectant, Chilean fish pathogens, Atlantic salmon

Microscopic theory of Cooper pair beam splitters based on carbon nanotubes

We analyze microscopically a Cooper pair splitting device in which a central superconducting lead is connected to two weakly coupled normal leads through a carbon nanotube. We determine the splitting efficiency at resonance in terms of geometrical and material parameters, including the effect of spin-orbit scattering. While the efficiency in the linear regime is limited to 50% and decay exponentially as a function of the width of the superconducting region we show that it can rise up to $\sim 100$ in the non-linear regime for certain regions of the stability diagram.Comment: 5 pages, 5 figure

Charging a Double Kerr Solution in 5D Einstein--Maxwell--Kalb--Ramond Theory

We consider the low-energy effective action of the 5D Einstein-Maxwell-Kalb-Ramond theory. After compactifying this truncated model on a two-torus and switching off the U(1) vector fields of this theory, we recall a formulation of the resulting three-dimensional action as a double Ernst system coupled to gravity. Further, by applying the so-called normalized Harrison transformation on a generic solution of this double Ernst system we recover the U(1) vector field sector of the theory. Afterward, we compute the field content of the generated charged configuration for the special case when the starting Ernst potentials correspond to a pair of interacting Kerr black holes, obtaining in this way an exact field configuration of the 5D Einstein-Maxwell-Kalb-Ramond theory endowed with effective Coulomb and dipole terms with momenta. Some physical properties of this object are analyzed as well as the effect of the normalized Harrison transformation on the double Kerr seed solution.Comment: 15 pages in latex, revised versio

Why does gravitational radiation produce vorticity?

We calculate the vorticity of world--lines of observers at rest in a Bondi--Sachs frame, produced by gravitational radiation, in a general Sachs metric. We claim that such an effect is related to the super--Poynting vector, in a similar way as the existence of the electromagnetic Poynting vector is related to the vorticity in stationary electrovacum spacetimes.Comment: 9 pages; to appear in Classical and Quantum Gravit