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.

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.

Estética y orden como sinónimos de belleza: El caso de la ciudad de San Salvador de Jujuy Romero, María Agustina El presente trabajo intentará un recorrido por la estética de la ciudad de San Salvador de Jujuy en el período 2007-2008, revisando para ello la idea de orden desde la cual se establece y responde para su ornamentación. Existen decisiones y elecciones sobre la ciudad que claramente no son tomadas por cualquier habitante, sino que, solo algunos contarán con un margen para accionar. Son ellos, como sujetos pertenecientes a un sector hegemónico de la ciudad, quienes tendrán la tarea de decidir qué elementos se escogerán para la ciudad, dónde y cómo se los ubicarán; inclusive, se decidirá cuál será considerado el centro de la ciudad, entre los distintos y diversos centros que coexisten, no todos serán centro, solo uno cumplirá tal condición. La ciudad encarna un prototipo a seguir, existe una idea preconcebida de cómo debería ser la verdadera ciudad, qué elementos son indispensables e infaltables para llegar a ser moderna y urbana.¿Qué sucede con esos elementos, esos modos de habitar, de vivir, de transitar la ciudad que no se corresponden con el prototipo de ciudad moderna. A lo largo del trabajo se intentará responder este interrogante que no es otra cosa que una revisión de aquellos elementos que quedan por afuera del centro.

Phylogenetic relationships of Fusarium poae based on EF-1α and mtSSU sequences Stenglein, Sebastian Alberto; Rodriguero, Marcela Silvina; Chandler, Damián Diego Enrique; Jennings, Philip; Salerno, Graciela Lidia; Nicholson, Paul A molecular phylogenetic analysis of Fusarium poae isolates from South America (Argentina) and Europe (mainly England, Germany, Italy) was performed using 98 F. poae, four Fusarium culmorum, two Fusarium sporotrichioides and one Fusarium langsethiae isolates. Phylogenetic analyses were performed using nuclear (translation elongation factor 1-alpha, EF-1α) and mitochondrial (mitochondrial small subunit rDNA, mtSSU) sequences. Partitioned (each dataset separately) and combined (EF-1α + mtSSU) analyses did not reveal any clear correlations from the inferred branching topology, between the distribution of observed haplotypes and the geographic origin and/or host species. Results from the present study confirmed that isolates from F. poae form a monophyletic group, and the low variability within isolates from a broad geographic range suggests a common lineage history. Among F. poae isolates from Argentina, however, some were found to possess an insert within mtSSU with structural similarities to group IC2 introns. F. poae isolates differing by the presence/absence of a mtSSU insertion were characterized further by analysis of a portion of the Tri5 gene, but this sequence was unable to reveal variability. The presence of this insert only within isolates from Argentina suggests that evolutionary events (insertions/deletions) are probably taking place within the Argentinian F. poae isolates, and that the acquisition of this insert occurred after geographic isolation of the Argentinian and European populations.

Transverse Mode Selection in Vertical-Cavity Surface-Emitting Lasers With Optical Injected Signal Torre, Maria Susana; Valle, Angel; Pesquera, Luis The transverse mode selection induced by optical injection in a VCSEL emitting in two transverse modes is analyzed from a theoretical point of view. Different pairs of transverse modes with parallel or orthogonal polarizations are considered. In general, we show that transverse mode selection can be achieved when the two modes have parallel or orthogonal polarizations. The selection is not possible only when both modes have parallel polarizations and the mode with the lowest threshold current has a lower injection rate than the other mode. Different forms of the selection region in the injected power-injection current plane appear depending on the polarization of the transverse modes. When both transverse modes are orthogonally polarized the mode with the lowest threshold is selected when the injected power surpasses a value that depends on the injection current. However when both modes have parallel polarizations the selection region has a completely different shape because the selection of the mode is no longer possible if the injected power or the injected current are large enough. We also show that the modal selection is favoured as the frequency of the injected light becomes smaller than the frequency of the mode to be selected.

Entre jueces y comandantes: formas de autoridad en la campaña tucumana a mediados del siglo XIX Parolo, María Paula El poder militar, heredero de la revolución y la guerra, se infiltró en todos los ámbitos de la sociedad hispanoamericana pos-independiente. Así, las nuevas autoridades militares devenidas de dicho proceso comenzaron a disputar con los agentes del poder civil sus atribuciones, facultades y competencias, conformándose una imbricada red de jerarquías de mando superpuestas. En este contexto, el objetivo de este trabajo es analizar el juego de poder entre las autoridades de la campaña tucumana (Jueces de Distrito y Comandantes Departamentales) a partir de sus acciones y prácticas (sumarios, juicios, denuncias, correspondencia, etc.) y los alcances de sus políticas sobre la población que debían controlar.

Effects Of Unsaturated Fatty Acids On The Conformational State Of Nicotinic Acetylcholine Receptor Perillo, Vanesa Liliana; Barrantes, Francisco Jose; Antollini, Silvia Susana Free fatty acids (FFA) are non-competitive antagonists of the nicotinic acetylcholine receptor (AChR) and their site of action is supposedly located at the lipid-AChR interface, where lipids can be annular or non-annular. It is known that the cis-unsaturated FFA, and not trans-unsaturated FFA, produce conformational modifications in the AChR resting state. Using T. californica receptor-rich membranes, we studied the changes in AChR conformational state generated by differences in the double-bond position of monounsaturated FFA. Using the higher affinity of the fluorescent AChR blocker crystal violet for the desensitized than for the resting state, it was observed that a double bond in positions ù 6 or ù 9 increased the KD values of the AChR in the desensitized state whereas no effect was observed in ù 11 or ù 13. Only FFAwith an ù 9 double bond changed the KD values in the resting state. DPH and Laurdan fluorescence studies showed that fluidity increased the most in FFAwith ù 9 and ù 11 double bonds and that ù 6 and ù 13 had less effect. Fluorescence resonance energy transfer experiments showed that the FFAwith an ù 6 double bond remained as an annular lipid whereas all the others also interact at non-annular sites. Thus, the location of the unsaturated double bond appears to be of critical importance for FFA-AChR interaction.

High-energy particle interactions in the inner jet of the radio galaxy M87 Guennou, Chloé; Gustavo E. Romero; Vila, Gabriela Soledad Recent observations with the High Energy Stereoscopic System (HESS) have revealedstrong and variable high-energy gamma-ray emission from the radio galaxy M87. Theorigin of such emission is uncertain, but the rapid variability indicates that it shouldbe produced close to the central engine of the source. In this work, a lepto-hadronicone-zone model is applied to the available multiwavelength data of M87. The differentenergy losses for both primary and secondary particles are calculated. Then, the differentcontributions to the spectral energy distribution through interactions with matter,radiation and magnetic fields are obtained, in good accordance with the observations.

Jet-cloud interactions in AGNs Araudo, Anabella Teresa; Bosch Ramon, Valentí; Romero, Gustavo Esteban Active galactic nuclei present continuum and line emission. The former is produced by the accretion disk and the jets, whereas the latter is originated by gas located close to the super-massive black hole. The small region where the broad lines are emitted is called the broad-line region. The structure of this region is not well known, although it has been proposed that it may be formed by small and dense ionized clouds surrounding the supermassive black-hole. In this work, we study the interaction of one cloud from the broad line region with the jet of the active galactic nuclei. We explore the high-energy emission produced by this interaction close to the base of the jet. The resulting radiation may be detectable for nearby non-blazar sources as well as for powerful quasars, and its detection could give important information on the broad line region and the jet itself.

Acción del ejercicio moderado crónico sobre la masa ósea: Estudio experimental Bryk, Gabriel; Pietrelli, Adriana; Paglia, Nora Patricia; Orzuza, R.; Zeni, Susana Noemi; Basso, Nidia Antecedentes: El tejido óseo responde a procesos dinámicos de carga (actividad física) mayores a los realizados en la vida cotidiana iniciando y favoreciendo la osteogénesis, disminuyendo la glucosa (Glu), colesterol total (Col. T), LDL-colesterol, triglicéridos (TG) y aumentando la fracción HDL-colesterol. Objetivo: Investigar cambios en DMO y contenido mineral (CMO) por efecto del ejercicio aeróbico crónico en ratas. Materiales y Métodos: Ratas Wistar machos (200-300g) se asignaron aleatoriamente a entrenamiento aeróbico (EA) (N=8) ó control sedentario (CS) (N=8) desde los 2 hasta los 12 meses de edad en un “treadmill” motorizado para desarrollar rutina aeróbica: moderada intensidad y ajustes en carga en función del rendimiento, simulando al humano Al sacrificio (12 meses) se midió la composición corporal, CMO (g) y DMO (mg/cm2) (Small Animal Software, Lunar DPX) y en suero calcio (Ca), fósforo (P), fosfatasa alcalina ósea (FAO), Col-T, Glu y TG. Resultados (X±SD): Ratas Cs vs. EA: CMO (g):13,4±1,4 vs. 16,6± 0,8*Área (cm2): 39,2±3,2 vs 46,6±1,7*, DMO (mg/cm2): 342±80 vs 356±50; Grasa (%):28,3±3,9vs.11,8±3,5*;Tejido total (g): 581±46 vs. 562±41 ;Grasa (g): 165,5±32,2 vs. 66,7±23,2*;Tej.Magro (g): 415±26 vs. 495±31*; Col.T(mg/dL): 121±6,8 vs. 115±7,8*; Glu (mg/dL): 182±28 vs. 191±12; (*) p<0.01 EA vs. CS. Conclusiones: El ejercicio aeróbico crónico mejoró significativamente la masa ósea y masa magra que, junto a disminución de masa grasa para un mismo peso corporal, sugiere la existencia de una correlación negativa entre tejido graso y osteogénesis. Subsidio: Asociación de Fomento a la Investigación Científica (AFIC).

The Hopf algebra of Möbius intervals Lawvere, F. W.; Menni, Matías An unpublished result by the first author states that there exists a Hopf algebra H such that for any Moebius category C (in the sense of Leroux) there exists a canonical algebra morphism from the dual H* of H to the incidence algebra of C. Moreover, the Moebius inversion principle in incidence algebras follows from a `master´ inversion result in H*. The underlying module of H was originally defined as the free module on the set of iso classes of Moebius intervals, i.e. Moebius categories with initial and terminal objects. Here we consider a category of Moebius intervals and construct the Hopf algebra via the objective approach applied to a monoidal extensive category of combinatorial objects, with the values in appropriate rings being abstracted from combinatorial functors on the objects. The explicit consideration of a category of Moebius intervals leads also to two new characterizations of Moebius categories.