Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods Rigano, Luciano Ariel; Marano, María Rosa; Castagnaro, Atilio Pedro; Morais do Amaral, Alexandre; Vojnov, Adrián Alberto Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment.

Semantically characterizing collaborative behavior in an Abstract dialogue framework Marcos, Maria Julieta; Falappa, Marcelo Alejandro; Simari, Guillermo Ricardo A fundamental requirement of collaborative dialogue formal systems is ensuring both that all the relevant information will be exposed and also irrelevancies will be avoided. The challenge is to fulfill this requirement in the context of a distributed MAS where each agent is unaware of the private knowledge of the others. We argue that it is possible to give a general treatment to this problem in terms of relevance notions, and propose a partial solution which reduces the problem to that of finding adequate potential relevance notions. Specifically, we present in this work an Abstract Dialogue Framework which provides an environment for studying the behavior of collaborative dialogue systems in terms of abstract relevance notions, together with three Collaborative Semantics each of which defines a different collaborative behavior of the dialogues under the framework. One of these semantics describes an utopian, non practical, behavior which is approximated in different ways by the other two constructive semantics. Complete examples are provided in Propositional Logic Programming. © 2010 Springer Berlin Heidelberg.

Effect of the association of reduced glutathione and ciprofloxacin on the antimicrobial activity in Staphylococcus aureus Páez, Paulina Laura; Becerra, María Cecilia; Albesa, Inés We report the effect of glutathione and the role of reactive oxygen species (ROS), assayed by a nitro blue tetrazolium reaction, on the antibacterial action of ciprofloxacin, gentamicin and chloramphenicol in Staphylococcus aureus 22 resistant to ciprofloxacin and gentamicin, and in S. aureus ATCC 29213 sensitive to the above three antibiotics. The association of glutathione with ciprofloxacin or gentamicin significantly reduced the value of the minimum inhibitory concentration (MIC) in resistant S. aureus 22, measured using the macrodilution method, with a concomitant increase of intracellular ROS and a decrease of extracellular ROS. However, glutathione did not induce modifications in MIC or ROS generated by chloramphenicol. Furthermore, in the sensitive S. aureus ATCC 29213, the association of glutathione with ciprofloxacin, gentamicin or chloramphenicol did not induce any significant variations of MIC or ROS. There was a correlation between the stimulus of intracellular ROS and the decrease of MIC caused by exogenous glutathione. According to the results obtained, it is possible to modify the sensitivity of resistant strains of S. aureus by the addition of exogenous glutathione.

Age-related differential sensitivity to cadmium in Hyalella curvispina (Amphipoda) and implications in ecotoxicity studies Garcia, M. E.; Rodrigues Capitulo, Alberto; Ferrari, Lucrecia The standardization of toxicity tests requires the selection of the most suitable test species and their developmental stages, as well as the selection of the appropriate assay matrix and the evaluation of the sensitivity of the test species to the reference toxicants. International protocols recommend the use of the amphipod Hyalella azteca from the Northern Hemisphere for sediment toxicity tests. We selected the widely distributed amphipod Hyalella curvispina, representative of pleustonic, epiphitic and zoobenthic assemblages in austral South America, as test species to be used in regional studies. Our goals were to evaluate the sensitivity of three developmental stages of H. curvispina to cadmium as a reference toxicant and to select the most suitable age and exposure time for aquatic ecotoxicity assessment. The three ages were highly susceptible to cadmium, with sensitivities: neonates > adults > juveniles. Our results validate the use of the native H. curvispina as a standard species for ecotoxicological assessment studies.

La heterogeneidad estructural vista desde tres teorías alternativas: el caso de Argentina Chena, Pablo Ignacio El presente artículo consta de dos secciones principales. En la primera de ellas se desarrolla una revisión del concepto de heterogeneidad estructural (HE) desde un marco teórico compuesto por tres teorías alternativas: la estructuralista, la neo-estructuralista y un enfoque monetario de origen regulacionista. En la segunda, estos conceptos son aplicados al estudio de la HE en Argentina, durante el período 1991-2006, ponderando la relevancia de cada una a la hora de explicar el fenómeno.

On the asymptotic behavior of general projection-pursuit estimators under the common principal components model Boente Boente, Graciela Lina; Molina, Fernanda Julieta; Sued, Raquel Mariela The common principal components model for several groups of multivariate observations assumes equal principal axes among the groups. Robust estimators can be defined replacing the sample variance by a robust dispersion measure. This paper studies the asymptotic distribution of robust projection-pursuit estimators under a common principal components model.

Solving a multicoloring problem with overlaps using integer programming Méndez Díaz, Isabel; Zabala, Paula Lorena This paper presents a new generalization of the graph multicoloring problem. We propose a Branch-and-Cut algorithm based on a new integer programming formulation. The cuts used are valid inequalities that we could identify to the polytope associated with the model. The Branch-and-Cut system includes separation heuristics for the valid inequalities, specific initial and primal heuristics, branching and pruning rules. We report on computational experience with random instances.

A novel OXA-10–like β-lactamase is present in different Enterobacteriaceae Porto, Ayelen Patricia; Ayala, Juan; Gutkind, Gabriel Osvaldo; Di Conza, José Alejandro OXA 101, a novel OXA-10 like enzyme, was found forming part of a class 1 integron located in a conjugative plasmid in three different species of Enterobacteriaceae. This β-lactamase is related to OXA-35 and OXA-56 and displays a narrow substrate hydrolysis profile.

Crystallite size-dependent phases in nanocrystalline ZrO2–Sc2O3 Abdala, Paula Macarena; Fantini, Márcia C. A.; Craievich, Aldo Felix; Lamas, Diego Germán ZrO2-10, 12 and 14 mol% Sc2O3 nanopowders were prepared by using a nitrate-lysine gel-combustion synthesis. These materials were studied by synchrotron X-ray powder diffraction (SXPD) and Raman spectroscopy after calcination at different temperatures from 650 to 1200 1C, which led to samples with different average crystallite sizes, up to about 100 nm. The results from SXPD and Raman analyses indicate that, depending on Sc2O3 content, the metastable t0 0-form of the tetragonal phase or the cubic phase are fully retained at room temperature in nanocrystalline powders, provided an average crystallite sizes lower than B30 nm. By contrast, powders with larger average crystallite sizes exhibit the stable rhombohedral, b and g, phases and do not retain or very partially retain the metastable t0 0 and cubic ones.

The overgeneralization of linear models among university students´ mathematical productions: a long-term study Esteley, Cristina Beatriz; Villarreal, Monica Ester; Alagia, Humberto Raul Over the last several years, we have been exploring and researching on a phenomenon that occurs among undergraduate students which we called extension of linear models to non-linear contexts or overgeneralization of linear models. This phenomenon appears when some students use linear representations in situations that are non-linear. In a first phase, we recognized and characterized the overgeneralization among agronomy majors while working with different kind of problems. This process let us raise some conjectures about the statement of the problems that were studied in a second phase. In a third phase we conducted some interviews in order to deep our understanding. The study allowed us to discuss: a) the robustness and broadness of the linear models as tacit models among university students, b) the emergence of a tension between unrealistic tasks posed by the teacher/researcher and the students? realistic interpretation of it, and c) some considerations about the teaching environment at university level.

Estrategias bioclimáticas aplicadas, monitoreo y simulación en una vivienda rural de interés social Garzon, Beatriz Silvia; Hernández, Alejandro Luis; Mele, Eduardo; De Benito, Liliana Este trabajo propone "el análisis de las estrategias de diseño bioclimático adoptadas y la verificación del comportamiento térmico de un caso de vivienda rural bioclimática producida por el Estado en la Provincia de Chubut". Los objetivos planteados son:- Mostrar la aplicación de estrategias y pautas de diseño bioclimático-energético en una vivienda rural de interés social - Mostrar la aplicación de estrategias y pautas de diseño bioclimático-energético en una vivienda rural de interés social - Simular su comportamiento térmico.- Verificar el mismo a través de mediciones. - Verificar el mismo a través de mediciones.- Confrontar la misma con los datos obtenidos de las mediciones.- Confrontar la misma con los datos obtenidos de las mediciones.

Interacciones planta-animal en la Sierra de San Javier Blendinger, Pedro Gerardo; Giannini, Norberto Pedro En este capítulo se definen los principales tipos de interacciones planta-animal, incluyendo casos de mutualismo como polinización y dispersión de semillas, y de antagonismo como herbivoría y depredación de semillas, ilustrando efectos directos e indirectos de cada interacción y brindando ejemplos para la sierra de San Javier (SSJ), Tucumán, Argentina. Prácticamente, la totalidad de las características y ejemplos que se mencionan en la descripción de los tipos de interacciones pueden encontrarse en SSJ. A pesar de ello, el conocimiento empírico publicado sobre interacciones en SSJ es aún incipiente, por lo cual existe un potencial enorme subutilizado para la investigación de estas interacciones en la sierra y en la región. La única interacción estudiada en profundidad en SSJ es entre vertebrados frugívoros y plantas frutales. Al menos 20 especies de aves y tres de murciélagos consumen frutos carnosos de unas 100 especies de plantas y dispersan sus semillas; algunos mamíferos arborícolas y terrestres establecen interacciones adicionales de menor intensidad pero fundamentales para algunas plantas. Tres cuartas partes de todas las plantas leñosas y epífitas dependen de esta interacción para reclutar sus propágulos, de lo que se deduce su importancia para el mantenimiento y regeneración de la biodiversidad en SSJ. La depredación de semillas por ratones es intensa y puede destruir casi la totalidad de la producción anual de semillas de algunas poblaciones de árboles. Especies introducidas e invasoras intervienen en las diferentes interacciones influyendo sobre el funcionamiento del bosque y los servicios ecológicos que brinda, como flores y frutos de plantas invasoras cuya propagación en la sierra depende de mutualistas nativos. La SSJ ofrece múltiples servicios al bienestar humano y, en forma directa o indirecta, las interacciones planta-animal intervienen en el mantenimiento de muchos de estos servicios, incluyendo la captura de agua y la contención de la erosión.

Figuras para pensar la comunidad: un análisis de las revistas Eco contemporáneo y Contracultura, 1960-1971 Gatto, Ezequiel Guillermo Nuestro trabajo consiste en presentar un contrapunto entre una serie de ideas enunciadas en las páginas de dos revistas argentinas (Eco contemporáneo y Contracultura) durante los años sesenta y principios de la década siguiente alrededor de la pregunta o inquietud por la comunidad desde una perspectiva político-cultural y ciertas elaboraciones que la teoría sociológica ha dedicado en el último tiempo al problema comunitario. Generadas en el seno de prácticas contraculturales y disidentes, las ideas que circulaban en aquellas revistas pueden ser analizadas recuperando críticamente nociones tales como la de "comunidades postsocietales" de Pablo de Marinis, la de "nuevas formas de asociación" de Vargas Cetina, así como los diagnósticos y juicios de Zygmund Bauman y Luis Tapia en torno a las nuevas modalidades de agrupamientos. En ese sentido, pretendemos tensar los enunciados presentes en aquellas revistas esperando aportar, desde el análisis histórico, a la discusión sobre un tópico que, abordado desde diversas perspectivas disciplinarias, ha recobrado potencia como problema sociológico, cultural y político durante los últimos años.

La Guerrilla del Ejército Libertador: Vicisitudes políticas de una guerrilla urbana Campos, Esteban Javier; Rot, Gabriel La Guerrilla del Ejército Libertador es un eslabón perdido entre la primer etapa de la guerrilla en la Argentina, que se inicia en 1959, y el surgimiento de las organizaciones político-militares de la década de 1970. En su intento de conformar un gran frente integrado por militantes de diversas tradiciones políticas, la experiencia del GEL constituye un jalón en la estructuración de nuevos modos de intervención revolucionaria. Lo significativo de este intento será el esfuerzo por confiar en la unidad de acción contra la dictadura basada en la lucha armada, más allá de la homogeneización ideológica de sus actores y de la integridad que exige un proyecto político unitario.

Políticas de educación y su impacto sobre la superación de la pobreza infantil Cortes, Rosalia Alba; Giacometti, Claudia El documento examina el rol que han tenido en América Latina las políticas educativas y sociales sobre las capacidades de acceso, permanencia y de logros educativos de niños y niñas socialmente vulnerables, –habitantes de zonas rurales y urbanas– marginales, pobres, pertenecientes a minorías étnicas y raciales. Se analizaron las estrategias educativas de las reformas de los años noventa, que intentaron ampliar el acceso al sistema educativo en condiciones de elevados déficit fiscales y bajo margen de maniobra. La reestructuración administrativa, en particular la descentralización de los servicios educativos fueron ejes centrales de las reformas. Sin embargo éstas no fueron acompañadas por transferencias adecuadas a los gobiernos subnacionales. Se implementaron subsidios a la demanda, a través de becas escolares dirigidas a mejorar la retención, en ampliaciones de la infraestructura escolar mediante programas que no cubrían las brechas de la oferta. La expansión de la matrícula en algunos casos se hizo a expensas de la calidad de la enseñanza, sin abarcar o fortalecer las condiciones necesarias de aprendizaje en áreas, localidades y escuelas con alta incidencia de alumnado pobre. La nueva agenda educativa enfatiza el papel de la educación para alcanzar la equidad social En un clima económico de crecimiento, con consensos entre gobiernos e instituciones internacionales acerca de las obligaciones estatales, con crecientes demandas de la sociedad civil, los Estados cuentan con más medios, pero las obligaciones son mayores. Las limitaciones impuestas por la restricción fiscal fueron hasta el 2008 menos acuciantes que en la década anterior, pero resultan de peso frente al aumento de las demandas.

Thermal behavior of sphingomyelins with very long chain polyunsatturated fatty acids (VLCPUFA) Peñalva, Daniel Alejandro; Furland, Natalia Edith; Aveldaño, Marta Isabel; Antollini, Silvia Susana Rat germ cells and spermatozoa contain species of SM and Cer with 28:4n-6 and 30:5n-6, followed by 32:5n-6, as main nonhydroxy (n) and 2-hydroxy (2-OH) VLCPUFA. The aim of this study is to gain some insight into the properties of these unique sphingolipids in membranes. Total SM from rat testis was partially separated by TLC into two main fractions: SM1, containing n-VLCPUFA, and SM2, containing similar proportions of 16:0 and 18:0 as well as 2- OH VLCPUFA. Each was then separated into molecular species by HPLC. Liposomes formed with these fractions or species were prepared and the generalized polarization of the fluorescent probe Laurdan as a function of temperature was followed. The effects of adding various % of these SM upon the transition temperature (Tt) of dipalmitoyl and dimiristoyl phosphatidylcholine (DPPC, DMPC) were also determined. The Tt of SM1 was significantly lower than that of SM2. In turn, the Tt of SM2 was lower than that of 16:0-SM, 18:0-SM, or a 50:50 mixture of 16:0-SM/18:0-SM, indicating that the presence of SM with 2-OH VLCPUFA in SM2 accounts for this decrease. The Tt of DPPC and DMPC decreased and increased with SM2, respectively, and decreased when SM1 or species with n-VLCPUFA were added. The potential increase in Tt that could have resulted from their unusually long carbon chains is thus overriden by the effect the double bonds have in decreasing it.

The anticonvulsive drug oxcarbazepine is a nicotinic acetylcholine recptor channel blocker Valles, Ana Sofia; Barrantes, Francisco Jose Oxcarbazepine is an anticonvulsive and mood-stabilizing drug used in the treatment of some forms of epilepsy. Here, we tested the effect of the drug on the ion channel properties of the nicotinic acetylcholine receptor (AChR). Electrophysiological recordings using the single-channel recording patch-clamp technique were used to evaluate AChR function in the presence or absence of different concentrations of oxcarbazepine. The main effects caused by the drug were a concentration-dependent decrease in channel mean open time, an increase in one of the components of the mean burst duration, ôburst, concomitant with a decrease in the duration of the second ôburst component, and the appearance of a new closed-channel component. The duration of the latter remained constant in the range of concentrations tested, although its relative contribution showed concentration-dependent behavior. It is concluded that oxcarbazepine blocks the AChR channel, allowing it to reopen quickly, through a mechanism compatible with that of channel blockers

Efecto de la introducción de negaciones sobre la dificultad de los argumentos condicionales simbólicos; Effect of the introduction of negations on the difficulty of symbolic conditional arguments Picón Janeiro, Jimena Cristina; Galibert, María Silvia; Abal, Facundo Juan Pablo; Lozzia, Gabriela Susana; Blum, Germán Diego; Attorresi, Horacio Felix En este trabajo se estudio la dificultad para evaluar la validez de los argumentos condicionales Modus Ponens (MP), Modus Tollens (MT), Negación del Antecedente (NA) y Afirmación del Consecuente (AC) de contenido simbólico cuando se introducen negaciones explícitas en el antecedente y/o el consecuente de la premisa mayor. No se encontraron diferencias significativas entre los porcentajes de aceptación en MP y AC de acuerdo a la presencia o no de negaciones. En MT el argumento con antecedente y consecuente negado obtuvo un porcentaje de aceptación significativamente menor a los que tienen negados un sólo componente. En NA el argumento con ambas cláusulas negadas tiene un porcentaje de aceptación menor al resto. Se discuten las implicaciones teóricas de estos resultados a partir de su comparación con los patrones propuestos en Schroyens, Schaeken y D´Idewalle (2001).

Usos del tiempo, violencias, consumo de drogas y sexualidad en jóvenes en espacios recreativos nocturnos en tres ciudades argentinas Mendes Diz, Ana Maria; Di Leo, Pablo Francisco; Schwarz, Patricia Karina Natalia; Adaszko, Dan; Camarotti, Ana Clara En el presente documento se resumen los hallazgos de la etapa cuantitativa de la investigación que este equipo viene llevando a cabo en torno a los usos del tiempo y los consumos de los jóvenes de ciudades de tamaño intermedio en los espacios recreativos nocturnos a los que suelen concurrir.; This document summarizes the findings of the quantitative stage of the research that this team has been carrying out about use of time and consumption in nightlife in the spaces to which young people living at medium-sized cities use to attend.

Experimental error control during immune monitoring by flow cytometry of positive reactors to bovine Traversa, María Julia; Saracco, Mónica Olga; Davis, William; Eluchans, Mariano; González, Facundo; Paolicchi, Fernando Alberto; Estein, Silvia Marcela; Rodriguez, Edgardo Mario; Jorge, María Cristina Flow cytometry (FC) has become the method of choice for studying the immune response to infectious agents. The development of an extensive set of monoclonal antibodies (MAb) to bovine leukocyte differentiation molecules has now made it possible immune response characterization in bovine tuberculosis (Tbc). Before extending these studies it is essential to establish results consistency. Currently indirect labeling (IL) is used in single and multiparameter analysis. This introduces the probability of experimental error because of the multiple processing steps needed. The objective of this study was to develop and test a strategy for assuring the reliability of methods for processing peripheral blood mononuclear cells (PBMC) from Tbc positive cattle. PBMC were obtained from 10 Tbc positive cows by density gradient centrifugation (Histopaque1077). Each sample was labeled with four MAb cocktails (antiCD4-IgM/antiCD25-IgG1, antiCD4/antiCD45Ro-IgG, antiCD8-IgM/antiCD25, antiCD8/antiCD45Ro), then they were washed and labeled with antiIgG1-PE/anti-IgM-FITC cocktail. Finally PBMC were fixed, stored and 10000 events were acquired with cytometer FACS-CANTO (Becton-Dickinson). Data were analyzed with FCS Express trial version. A dot plot side light scatter (SSc) vs forward light scatter (FSc) was set to define the mononuclear cell population. Then a dot-plot FSc vs fluorescence distinguished between unlabeled and labeled cells. Finally a histogram is generated to compare geometric means of fluorescence intensity (GMFs). SAS v 9.2 calculated the paired t test between duplicate GMFs. The variation in labeling between paired samples was very low, p value of paired t test >0.05 in all samples, showing that reliable results can be obtained with minimal differences introduced during sample preparation. When in FC IL is routine, statistical comparison of results from repetitions of the same sample labeled with the same MAb would be strategic as an experimental error control.