Convexity of the effective action from functional flows

We show that convexity of the effective action follows from its functional flow equation. Our analysis is based on a new, spectral representation. The results are relevant for the study of physical instabilities. We also derive constraints for convexity-preserving regulators within general truncation schemes including proper-time flows, and bounds for infrared anomalous dimensions of propagators.Comment: 4 pages, 3 figure

Model for Dissipative Highly Nonlinear Waves in Dry Granular Systems

A model is presented for the characterization of dissipative effects on highly nonlinear waves in one-dimensional dry granular media. The model includes three terms: Hertzian, viscoelastic, and a term proportional to the square of the relative velocity of particles. The model outcomes are confronted with different experiments where the granular system is subject to several constraints for different materials. Excellent qualitative and quantitative agreement between theory and experiments is found.Comment: Link to the Journal: http://prl.aps.org/abstract/PRL/v104/i11/e11800

Aspects of breeding biology of Chiguanco Thrush at Chaco Serrano of Córdoba, Argentina

Some parameters of the breeding biology of the Chiguanco Thrush (Turdus chiguanco) are described in Chaco Serrano forest of Córdoba, Argentina. Searching and monitoring of the Chiguanco Thrush nests were performed between October 2010 and February 2011. We monitored 35 nests of this species. Seven species of trees and bushes, two of them exotics, were used for nesting, mainly at medium height of the plant. Clutch size ranged between two to three eggs; only two nests were parasitized by the Shiny Cowbird (Molothrus bonariensis). The incubation period was 11–12 days long and nestlings hatched asynchronously in clutches of three eggs. Only 10% of nests were successful. From the unsuccessful nests, 97% were predated. The daily rate of nest predation was 0.86 ± 0.02. Only females were responsible for incubation. Females incubated intermittently for periods of 16:24 ± 3:16 min, and took recess bouts of 13:11 ± 2:20 minDescribimos parámetros de la biología reproductiva del Zorzal Chiguanco (Turdus chiguanco) en el Bosque Serrano de Córdoba, Argentina. Buscamos y monitoreamos nidos de la citada especie entre octubre 2010 y febrero 2011. Se siguieron un total de 35 nidos de esta especie. Siete especies de árboles y arbustos, dos de ellas exóticas, fueron usadas para nidificar principalmente a una altura media en la planta. El tamaño de la puesta osciló entre dos y tres huevos; sólo dos nidos fueron parasitados por el Tordo Renegrido (Molothrus bonariensis). El período de incubación fue de 11–12 días, y el nacimiento de los pichones fue asincrónico sólo en nidos con 3 huevos. Un 10% del total de nidos fueron exitosos. De los nidos no exitosos, la principal causa de fallo fue la depredación (97%). La tasa diaria de depredación de nidos fue de 0,86 ± 0,02. Sólo las hembras se encargaron de la incubación. Las hembras incubaron intermitentemente por períodos de 16:24 ± 3:16 min, tomando recesos fuera del nido de 13:11 ± 2:20 min.Fil: Vergara Tabares, David Lautaro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Centro de Zoologia Aplicada; ArgentinaFil: Peluc, Susana Ines. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Diversidad y Ecologia Animal; Argentina. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales. Centro de Zoologia Aplicada; Argentin

Delayed Scattering of Solitary Waves from Interfaces in a Granular Container

In granular media, the characterization of the behavior of solitary waves around interfaces is of importance in order to look for more applications of these systems. We study the behavior of solitary waves at both interfaces of a symmetric granular container, a class of systems that has received recent attention because it posses the feature of energy trapping. Hertzian contact is assumed. We have found that the scattering process is elastic at one interface, while at the other interface it is observed that the transmitted solitary wave has stopped its movement during a time that gets longer when the ratio between masses at the interfaces increases. The origin of this effect can be traced back to the phenomenon of gaps opening, recently observed experimentally.Comment: To appear in Physical Review E, vol 7

Realización de un Sistema Scada para el Control de Imagen Utilizando Imaq de Labview y Cámara de Objetos para el Laboratorio de Mecatrónica.

La tesis se basa en el desarrollo de un sistema SCADA (Supervisory Control and Data Acquisition) para el control de imagen utilizando IMAQ de LabVIEW (Laboratory Virtual Instrumentation Engineering Workbench) y cámara de objetos para el laboratorio de Mecatrónica, con el propósito de controlar, monitorear y supervisar instrumentos de medición, mostrar una interface hombre-máquina en forma práctica, se diseñó el panel frontal para supervisión de instrumentos, se realizó la comunicación entre la cámara y la PC por medio del cable USB y las librerías de IMAQ de LabVIEW. El sistema SCADA en conjunto con la cámara de objetos son el complemento idóneo para controlar, monitorear y supervisar instrumentos de medida tanto de forma pedagogía como práctica, el sistema consta de: Panel de botones para ajustar parámetros que cumple la función de posición inicial, posición final, aceptar, indicador numérico que muestra valores en tiempo real, y un botón de parar el cual detiene el sistema SCADA. Panel que genera reportes en Excel, permitiendo así tener un registro de las lecturas tomadas en forma gráfica y numérica. Panel de alarmas que permite avisar al supervisor cuando hay una condición anormal de operación de la máquina. Con el desarrollo de este sistema SCADA se logra controlar y supervisar en tiempo real las lecturas de instrumentos de medida. Se recomienda utilizar la cámara de objetos y el sistema SCADA desarrollado para la enseñanza, de Mecatrónica aplicada, por sus características didácticas, visualización práctica en tiempo real del entorno utilizando el software de MimioStudio

Scattering of solitary waves in granular media

A detailed numerical study of the scattering of solitary waves by a barrier, in a granular media with Hertzian contact, shows the existence of secondary multipulse structures generated at the interface of two "sonic vacua", which have a similar structure as the one previously found by Nesterenko and coworkers.Comment: 4 pages, 9 figures (fig 5, replaced). Submitted to PR

Germination response of Lithraea molleoides seeds is similar after passage through the guts of several avian and a single mammalian disperser

Seed dispersal by vertebrate frugivores plays an important role in plant population dynamics and community structure. The gut treatment may modify the germination response of seeds; often the specific effects of seed ingestion are not consistent among frugivorous taxa. In the Chaco mountain woodlands of Argentina, an ecosystem threatened by human activities, frugivorous birds enhance the seed germination of the most abundant fleshy-fruited plants. However, the effect of the identity of dispersers on seed germination remains unknown. In this work, we evaluated and compared the seed germination response of Lithraea molleoides (Vell.) Engl. (the dominant tree of the region) to gut passage through three Turdus species and the Pampa Fox (Lycalopex gimnocercus). Owing to anatomical differences between the Turdus species and Pampa Fox, we expected to observe higher seed germination in the seeds treated by the gut of Turdus species compared with those that have passed through the Pampa Fox’s gut. Our results showed that germination response of L. molleoides seeds was positively related to gut passage through Turdus species and Pampa Foxes (without differences among seed dispersers). Consequently, both the avian species and the Pampa Fox contribute positively to the dispersal and germination of L. molleoides seeds.Fil: Vergara Tabares, David Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Whitworth Hulse, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Funes, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Synthesis and NMR structure determination of new linear geranylphenols by direct geranylation of activated phenols.

Indexación: Web of Science; ScieloThe known geranylhydroquinone 2, geranylorcinol 4 and the derivative (E)-4-(3,7-dimethylocta-2,6-dienyl)-5-methylbenzene-1,3-diol 5, were prepared by Electrophilic Aromatic Substitution (EAS) reactions between the corresponding phenol derivatives containing electron-donor subtituents and geraniol using BF3XOEt2 as a catalyst. In addition, spectroscopic NMR information for 4 and 5 is complemented. Furthermore, the new (E)-2-(3,7-dimethylocta-2,6-dienyl) benzene-1,3,5-triol (geranylphloroglucinol) 13, (E)-2-(3,7-dimethylocta-2,6-dienyl)-1,3,5-trimethoxybenzene 14, (E)-2-(3,7-dimethylocta-2,6-dienyl)-6-methoxyphenol 15, (E)-3-(3,7-dimethylocta-2,6-dienyl)-2-methoxyphenol 16, (E)-5-(3,7-dimethylocta-2,6-dienyl)-2-methoxyphenol 17, (E)-4-(3,7-dimethylocta-2,6-dienyl)benzene-1,3-diol 18, (E)-3-(3,7-dimethylocta-2,6-dienyl)benzene-1,2-diol 19, (E)-4-(3,7-dimethylocta-2,6-dienyl)-5-isopropyl-2-methylphenol 20, (E)-2-(3,7-dimethylocta-2,6-dienyl)-4-isopropyl-3-methylphenol 21, (E)-2-(3,7-dimethylocta-2,6-dienyl)-4-isopropyl-5-methylphenol 22, and(E)-2-tert-butyl-4-(3,7-dimethylocta-2,6-dienyl)-5-methylphenol 23 were also prepared with this synthesis strategy. All the synthesized compounds were fully characterized and their structures were established by IR, MS and mainly NMR spectroscopic dates.http://ref.scielo.org/3cj5t