Catalytic Degradation of Polystyrene: Modeling of Molecular Weight Distribution Gianoglio Pantano, Ioana Agustina; Asteasuain, Mariano; Diaz, Monica Fatima; Sarmoria, Claudia; Brandolin, Adriana Two of the most abundant polymers in household waste streams, PS and PE, may be recycled by compatibilization through a Friedel-Crafts alkylation. This reaction produces a graft copolymer PE-g-PS that improves the properties of the blend, but simultaneously degrades PS chains. Since the copolymer efficiency as a compatibilizer depends both on the molecular weight and MWD of its two blocks, the operating conditions for the copolymer synthesis must be carefully tuned. To aid in this task, we present a preliminary mathematical model that focuses on the effect of the catalyst and cocatalyst of the Friedel-Crafts alkylation on the MWD of the PS chains. The model's predictions are shown to agree with experimental data. The evolution of the complete MWD of PS subjected to Friedel-Crafts alkylation during reactive processing of thermoplastics from waste streams is modeled. This is the first step towards the development of a complete description of the graft reaction that will aid in the tuning of appropriate processing conditions.

Characterizing Trichoptera trophic structure in rivers under contrasting land use in Patagonia, Argentina Brand, Cecilia; Miserendino, Maria Laura Trichoptera is a widely distributed and diversified group in Andean Patagonia (Subandean Patagonic Province). This group exhibits a wide array of functional adaptations to exploit the available food resources. It is well known that changes in the relative abundance of functional-feeding groups (FFG) occur when the distribution of energetic resources (organic matter) is altered. In order to determine the functional structure variation among rivers subjected to different land uses, we selected 3 disturbance types (exotic plantation, pasture and logging) and native forest as reference. Three sites were assessed for each land use type (n=12) seasonally (every 3 months) and 6 samples with a Surber net (0.09 m-2 and 250 pore size) were taken. Larvae obtained were identified to the lowest possible taxonomic level, counted and assigned to a FFG using available references, knowledge of feeding modes and analysis of gut contents. A total of 32 taxa were identified belonging to 11 families. Mean annual densities of Trichoptera varied between 131 and 4231 ind.m-2. Pasture sites showed significantly higher density than pine and native forest sites. Overall Trichoptera FFG species composition was: shredder (10), predator (9), scraper (6), collector-filterer (5), algal-piercer (1), and collector-gatherer (1). The scraper Mastigoptila sp. was abundant in native forest rivers. Predators presented high density in logged forest sites. Shredders (53–98%) dominated rivers having dense forest cover; Parasericostoma ovale (Schmid) and Myotrichia murina Schmid (Sericostomatidae) being the most abundantspecies. Collector-filterers, mostly Smicridea annulicornis (Blanchard) and S. frequens (Navás)(Hydropsychidae), were the dominant group in pastures (42-96%), probably due to an increase of transported seston. According to these results, Trichoptera communities can be used as an early warning tool to assess changes in disturbed headwater systems in Patagonia.

Monte Carlo simulation of spectrum changes in a photon beam due to a brass compensator Custidiano, Ernesto Ramon; Valenzuela, Mercedes Raquel; Dumont, J. L.; McDonnell, J.; Rodriguez Aguirre, Juan Manuel Monte Carlo simulations were used to study the changes in the incident spectrum when a poly-energetic photon beam passes through a static brass compensator. The simulated photon beam spectrum was evaluated by comparing it against the incident spectra. We also discriminated the changes in the transmitted spectrum produced by each of the microscopic processes. (i.e. Rayleigh scattering, photoelectric effect, Compton scattering, and pair production). The results show that the relevant process in the energy range considered is the Compton Effect, as expected for composite materials of intermediate atomic number and energy range considered.

Improved state-variable internal model based digital controller for three-phase PWM inverters that complies with the standard IEC 62040-3 Botterón, Fernando; Humberto Pinheiro This paper proposes an improved state-variable internal model based digital voltage controller suitable for three-phase PWM inverters with output transformer for medium and high power uninterruptible power supplies (UPS). The proposed controller is derived from the internal model principle using a state-variable approach in stationary alfa-beta frame. For the controller design an improved discrete-time model that uses the average of two samples in a switching period is proposed. In addition, this model takes into account the digital implementation time delay. With the proposed controller it is possible to obtain a high performance in both steady-state and load transients. Also, with the selected internal model, dc components resulting from the circuit implementation non-idealities are not amplified, avoiding transformer saturation. To validate the proposed digital controller and to demonstrate the steady-state and transient performance, experimental results from a 10kVA space vector modulated three-phase inverter, fully controlled by a DSP TMS320F241, are presented. In steady-state the UPS output voltages have very low total harmonic distortion (THD) for both balanced and unbalanced non-linear loads. The output voltage dynamic performance complies with the international Standard IEC 62040-3 Classification 1, which is the most severe limit making the three-phase PWM inverter suitable for most types of critical loads.

Socio-environmental conditions, intestinal parasitic infections and nutritional status in children from a suburban neighborhood of La Plata, Argentina Gamboa, María Inés; Navone, Graciela Teresa; Orden, Alicia Bibiana; Torres, María Fernanda; Castro, Luis Eduardo; Oyhenart, Evelia Edith We analyzed intestinal parasitic infections in children aged 1-12 years from a poor neighborhood in La Plata, Argentina, and determined the correlations with their nutritional status and socio-environmental conditions. We performed parasitological analyses with anal brushed technique (for Enterobius vermicularis eggs) and fecal samples, employing the techniques of Ritchie, Carles Barthelemy and Willis. The worm burdens of nematodes were estimated by means of Kato Katz technique. Low weight-for-age (underweight), height-for-age (stunting) and weight-for-height (wasting) were calculated based on the 5th centile of the WHO 2006 (children under 5) and CDC 2000 (older children and adolescents) growth references. We also analyzed samples of soil, water, and canine feces and surveyed other domestic and environmental data using structured questionnaires to each child's parents. To associate the parasitological, anthropometric and socio-environmental data, a categorical analysis of principal components (catPCA) was conducted. In the first axis of catPCA, the correlations among socio-environmental variables showed a gradient of " relative welfare" The eigenvectors showed the most influential variables in the analysis were promiscuity (0.0765), father's education (-0.741), crowding (0.727), wastewater disposal (-0.658), mother's education (-0.574), and flooding (-0.409). The 85% of children were parasitized and 79.6% polyparasitized. The 27.7% of children had deficit in some nutritional status indicator, being the stunting the most prevalent deficit (16.8%). There also found parasites in 42% of the dog feces, 53% of the soil samples, and non-pathogenic amoebae in the water samples. The SEV was mainly associated with geohelminths and stunting, especially among the poorest children. The study evidences that living conditions are variable within this population. Part of these variations could be linked to the differences in the extent to which parents are able to use their scant resources to influence their children's morbidity. Further studies need to be done from a qualitative approach.

Cytotoxic and genotoxic effects of defence secretion of Ulomoides dermestoides on A549 cells Crespo, Rosana; Villaverde, Maria Luciana; Girotti, Juan Roberto; Güerci, Alba Mabel; Juarez, Marta Patricia; de Bravo, M.G. Ethnopharmacological relevance: Ulomoides dermestoides (Fairmaire, 1893) is a cosmopolitan tenebrionid beetle reared by Argentine people who consume them alive as an alternative medicine in the treatment of different illnesses such as asthma, Parkinson's, diabetes, arthritis, HIV and specially cancer. Aim of the study: To evaluate the cytotoxicity and DNA damage of the major volatile components released by Ulomoides dermestoides on human lung carcinoma epithelial cell line A549. Materials and methods: The defence compounds of Ulomoides dermestoides were extracted with dichloromethane and analyzed and quantified by capillary gas chromatography. The toxicity effects of the beetle's extract against A549 cell line were evaluated. Cytotoxicity was evaluated by MTT test and Trypan blue assay and genotoxicity was evaluated by the comet assay. The synthetic compounds, individually or combined, were also tested in A549 cells and normal mononuclear human cells. Results: The defence compounds of Ulomoides dermestoides extracted with dichloromethane (methyl-1,4-benzoquinones, ethyl-1,4-benzoquinones and 1-pentadecene as major components) showed cytotoxic activity on A549 cells demonstrated by MTT test and Trypan blue assay, with IC 50 values of 0.26 equivalent/ml and 0.34 equivalent/ml, respectively (1 equivalent = amount of components extracted per beetle). The inhibition of A549 cell proliferation with the synthetic blend (1,4-benzoquinone and 1-pentadecene) or 1,4-benzoquinone alone was similar to that obtained with the insect extract. 1-Pentadecene showed no inhibitory effect. Low doses of insect extract or synthetic blend (0.15 equivalent/ml) inhibited mononuclear cell proliferation by 72.2 ± 2.7% and induced significant DNA damage both in tumor and mononuclear cells. Conclusion: Results of this study demonstrated that defence compounds of Ulomoides dermestoides reduced cell viability and induced DNA damage. We also concluded that the insect benzoquinones are primarily responsible for inducing cytotoxicity and genotoxicity in culture cells.

Land use and basin characteristics determine the composition and abundance of the microzooplankton Jose, Susana Beatriz; Devercelli, Melina The influence of watershed land use on microzooplankton was examined. Six rivers and a shallow lake located in rural (agriculture, livestock) and urban areas were sampled during 4 weeks at low water, low temperatures and 3 weeks at high water, high temperatures. The major aim of this study was to analyze the composition, richness and abundance of the microzooplankton in relation to land use, taking into account nutrient concentration, biological oxygen demand (BOD 5), conductivity, pH, transparency, dissolved oxygen, and chlorophyll-a. Redundancy analysis was used to assess microzooplankton response to environmental gradients. The composition and abundance can be considered good indicators of the land used and characteristic of the basin (broad range of conductivity water). The species composition show a gradient along the conductivity, pH and chlorophyll-a. Brachionus spp. were associated with saline waters on rural area and Keratella spp. (except Keratella tropica) were associated with urban water bodies. The microzooplankton abundance diminished by a factor of ten from the rivers in livestock-agriculture-dominated watersheds to those located in strictly urban areas. Urban rivers had low abundances of chlorophyll-a and microzooplankton despite the high concentration of nutrients. However, the effect of urbanization (mesotrophic/mesosaprobious state and lead presence) cannot be analyzed alone due to the potential effect of a filter-feeding invasive mollusk that colonizes the hard surfaces of harbor buildings and bridge pillars.

Autonomía y estatización: Rupturas en el sindicalismo tucumano frente al fenómeno peronista; Autonomy and nationalization: Fractures in Tucuman’s trade unionism address the Peronist phenomenon Piliponsky, Esteban El presente trabajo tiene como objetivo ser un aporte tanto a la historia del movimiento obrero tucumano, cuyo campo está aún muy poco explorado, como así también a los debates sobre los orígenes del peronismo en la Argentina. El análisis de un espacio regional específico permite acrecentar y complejizar los conocimientos y estudios respecto al período, los cuales tienen una excesiva mirada sobre la zona metropolitana. Este artículo se plantea hacer una comparación entre las experiencias del sindicalismo en la provincia en los años previos al golpe de Estado de junio de 1943, y las transformaciones producidas tras el mismo. La hipótesis a demostrar es que los gremios de trabajadores sufrieron transformaciones internas entre un momento y otro, y no fueron los cambios producidos desde el Estado la única ruptura dentro del mundo del trabajo. ; The purpose of this article is to contribute to the history of the labor movement in Tucumán, whose field is still unexplored, and also to the debates on the origins of the Peronism in Argentina. The analyses of one specific regional space allow to increas and refin our knowledge on this period, which, until now, have an excessive focus on the metropolitan zone. This article considers to make a comparison between the experiences of trade unionism in the province in the previous years to the coup d’état of June of 1943, and their subsequent transformations. The hypothesis to be demonstrated is that the workers unions underwent internal transformations, and the changes produced from the State were not the unique rupture within the world of the labor movement.

Disodium-fosfomycin pharmacokinetics and bioavailability in post weaning piglets Soraci, Alejandro Luis; Pérez, Denisa Soledad; Martínez, Guadalupe; Dieguez, Susana Nelly; Tapia, Maria Ofelia; Amanto, Fabián Andrés; Harkes, Roberto; Romano, Omar Disodium-fosfomycin pharmacokinetics has been studied in different species after oral, intravenous, intramuscular and subcutaneous administration. At present there are neither documented clinical experiences of the use of fosfomycin in pigs nor any published studies in weaning piglets, although it is a period of high incidence of infectious diseases. The pharmacokinetics and the bioavailability of sodium fosfomycin were studied in post weaning piglets after intravenous and intramuscular administration of 15mg/kg of body weight. Plasma concentrations were measured by a high-performance liquid ms/ms. After IV administration the area under the fosfomycin concentration:time curve in plasma was AUC(0-12) of 120.00±23.12μgh/ml and the volume of distribution (Vd) of 273.00±40.70ml/kg. The elimination was rapid with a plasma clearance of 131.50±30.07ml/kg/h and a T1/2 of 1.54±0.40h. Peak serum concentration (Cmax), Tmax, AUC(0-12) and bioavailability for the IM administration were 43.00±4.10μg/ml, 0.75±0.00h, 99.00±0.70μgh/ml and 85.5±9.90% respectively. Different authors have determined a minimum inhibitory concentration (MIC90) ranging from 0.25μg/ml for Streptococcus sp. and 0.5μg/ml for Escherichia coli. Considering the above, and according to the values of plasma concentration vs time profiles observed in this study, effective plasma concentrations of fosfomycin for sensitive bacteria can be obtained following IV and IM administration of 15mg/kg in piglets.

Recomendaciones de restauración para las márgenes ribereñas de una cuenca urbana; Restoration recommendation for the river margins of an urban basin Melignani, Eliana; Faggi, Ana Maria El 30 % de la población argentina vive en el área metropolitana, donde la falta de planificación sumada a un uso descuidado del ambiente impacta severamente los cursos de agua. Un río muy representativo de esta situación es el río Matanza Riachuelo. Reclamos de la sociedad civil han impulsado a las autoridades a tomar medidas al respecto. Según los últimos informes de gestión de ACUMAR, se continúa con las tareas de limpieza, desmalezado y forestación de las márgenes a cargo de AySA. Son conocidas las ventajas de las plantaciones de árboles, como la protección costera, el secuestro de carbono y la provisión de una variedad de hábitats para la fauna. Sin embargo, la forestación sobre la línea de ribera puede ocasionar erosión dada la caída ocasional de ejemplares, dejando huecos profundos. A esta desventaja se suma el hecho de que las tareas de limpieza y desmalezado de las márgenes incluyen el corte de césped y de la mayoría de la vegetación helófita dejando amplios parches de suelo desnudo. Estos parches no sólo favorecen la acumulación clandestina de basura, sino que disminuyen la capacidad de filtración y depuración del agua y del suelo que proveen las plantas herbáceas, además de propiciar la invasión de especies exóticas en las márgenes. ¿Son entonces adecuadas las medidas actuales de limpieza y restauración de márgenes? Como alternativa se propone la conservación de la vegetación ribereña nativa, y la implantación de herbáceas nativas en aquellos sitios degradados, de manera de favorecer la biorremediación y conservación del suelo, agua y sedimentos.; The 30 per cent of the Argentinean population live in the metropolitan area, where the lack of planning and the neglecting care of the ambient impact severely over the water courses. A very representative river of this situation is the Matanza Riachuelo. Civil society claimed and the authorities took care about it- According to the last management reports of ACUMAR, the cleaning activities are still going on. The advantages of tree plantations are well known, such as the coast protection, the carbon took and the provision of a habitat variety for fauna. However, the forestation over the bank line might produce erosion for the occasional fall of trees, leaving deep holes. And what is more, the fact that cleaning activities and weeding of the margins include the cut of grass and most of the helophytic vegetation, big spaces of naked ground are left. These spaces favor the accumulation of garbage and shorten the capacity of filtration and depuration of water and ground. Then, are the current cleaning measures and margin restoration accurate? As an alternative, we propose the conservation of the native river vegetation and the implantation of native herbaceous on the degraded spaces, favoring the bioremediation and the conservation of ground, water and sediments.

Novedades nomenclaturales en Poaceae argentinas; Nomenclatural novelties in Argentinean Poaceae from Argentina Giussani, Liliana Mónica; Soreng, Robert J.; Anton, Ana Maria Ramona Se presentan seis nuevas combinaciones en los géneros Cortaderia, Nicoraepoa yPoa, y cuatro lectotipificaciones en el género Poa, como resultado de su estudio taxonómico para la Flora Vascular de la Argentina.; Six new combinations in the genera Cortaderia, Nicoraepoa, and Poa, and four lectotypifications in Poa are published here as the result of a taxonomic study for the Vascular Flora of Argentina.

La seguridad social en la posconvertibilidad: de privilegios a derechos universales Panigo, Demian Tupac; Dvoskin, Nicolás; Medici, Florencia El sistema de seguridad social es un instrumento estatal crucial para mejorar la calidad de vida de los sectores más vulnerables de la sociedad. Esta afirmación implica reconocer que el objetivo del sistema de seguridad social no es sólo el de proveer un ingreso a aquellas personas que ya no pertenecen a la fuerza laboral. En contraste, en los regímenes de capitalización, como las AFJP, prima una lógica exclusivamente contributiva en la que los beneficios recibidos del sistema se corresponden de manera lineal con los aportes realizados. En la Argentina, esta última concepción prevaleció durante la década de los noventa. Sin embargo, estamos ante una coyuntura novedosa. La eliminación del régimen de capitalización en 2008 revirtió la reforma neoliberal que había permitido la privatización del sistema previsional. Pero también añadió nuevas herramientas distributivas que permitieron la ruptura con aquel esquema conceptual para avanzar en la modificación del sistema de seguridad en un sentido amplio, abandonando la lógica íntegramente individual en pos de una concepción de un sistema solidario. La puesta en marcha de programas específicos, como la Asignación Universal por Hijo para la Protección Social y el Plan Nacional de Inclusión Previsional, muestra instrumentos claros de estas nuevas metas. El objetivo central del presente artículo es describir en qué han consistido estas nuevas modalidades y qué resultados han tenido en términos de mejoras sociales para dejar planteada la discusión acerca de la importancia de definir el sistema de seguridad social en el marco de una discusión más amplia de la sociedad que queremos.

Evolución del mercado de trabajo y de la estructura del empleo en la Provincia de Buenos Aires desde la convertibilidad (1991-2009) Neffa, Julio Cesar; Persia, Juliana; Bustos, Juan Martin; Oliveri, María Laura El artículo aborda la evolución del mercado de trabajo y de la estructura del empleo en la provincia de Buenos Aires durante el período 1991-2009. El análisis recurre a la articulación de una multiplicidad de fuentes de información para dar cuenta de los diferentes aspectos de los fenómenos laborales. A partir de la Encuesta Permanente de Hogares, se analizan los indicadores básicos de los mercados de trabajo urbanos en los principales aglomerados de la provincia y se lleva a cabo una caracterización de sus respectivas estructuras de empleo, considerando dimensiones tales como la categoría ocupacional, la composición público-privado, la condición de registro del empleo [registrado y no registrado] y el sector de actividad. Por otra parte, a nivel del total provincial, se analiza la evolución el empleo privado registrado y su composición sectorial. Para este tipo de análisis se utilizan datos procedentes de los registros administrativos que surgen de las declaraciones juradas de personal en relación de dependencia que realizan mensualmente los contribuyentes ante la AFIP. Estos datos permiten tratamientos muy desagregados de la información, de suma importancia para el análisis sectorial detallado. También a nivel del total provincial, se caracteriza al empleo público en sus distintos niveles de gobierno [nacional, provincial y municipal] a partir de fuentes presupuestarias y de otras, menos difundidas, elaboradas por distintos organismos públicos. El artículo ofrece análisis descriptivos de las variables mencionadas y un pormenorizado detalle metodológico respecto de las fuentes y el tratamiento de la información.

El MERCOSUR a la luz de la industria automotriz: integración productiva, intensificación del trabajo y acumulación de capital Guevara, Sebastián Luis En este trabajo se presentan los resultados de la investigación que se cristalizó en nuestra tesis doctoral. En ella se analizó el proceso de integración industrial automotriz en el MERCOSUR para avanzar en el conocimiento sobre la determinación general de éste, y a partir de ahí de las condiciones y perspectivas para la acción política en la región. En ese análisis se indagó sobre los efectos de la flexibilización laboral y de la integración productiva sobre las condiciones de trabajo y cobro de los trabajadores. Y cómo esas condiciones se fueron imponiendo al calor de la lucha de clases.; This paper presents the results of the research that crystallized in our doctoral thesis. The latter, analyzed the process of integration in Mercosur automotive industry to advance in the general knowledge of this determination, and from there to the conditions and prospects for political action in the region. In this analysis we researched the effects of labor flexibility and the integration of production on working conditions and payment of workers. And how those conditions were imposed in the heat of class struggle.

El primer intento en defensa del patrimonio jesuítico o una excusa para extirpar su memoria. El expediente sobre la demolición de la iglesia jesuítica de Asunción.; An attempt to defend the Jesuit Heritage or an excuse to erase its memory. The case of the Jesuit Church in Asunción, Paraguay Page, Carlos Alberto En el Archivo General de la Nación Argentina se encuentra un voluminoso expediente que trata sobre el tema de la demolición de la iglesia jesuítica de Asunción y del que Furlong se ocupó al pasar, cuando trabajó el tema en su libro sobre los arquitectos del Río de la Plata. Se trata de un estupendo alegato confeccionado por el ingeniero español Julio Ramón de César, quien intenta conservar un edificio jesuítico. Pero además de ello, encierra un testimonio contemporáneo que vislumbra las intenciones de extirpar de la memoria el paso de los jesuitas. Una actitud muy usada cuando se pretende diezmar la identidad de los pueblos: borrar su memoria, tanto oral como escrita, y también su memoria construida. Este trabajo intenta rescatar esa memoria justamente para dar a conocer las intenciones de un grupo humano que actuó en un tiempo no favorable a los jesuitas.; In the General Archives of the Argentine Nation there is a large fi le that deals with the issue of the demolition of the Jesuit Church in Asunción, subject which Furlong dealt with somewhat superfi cially, when he worked on the theme of his book on the architects of the River Plate. It is about a great argument made by the Spanish engineer Julio Ramón de César, who tries to preserve a Jesuit building. Moreover, it contains a contemporary testimony that envisages the attempts to erase from the memory the presence of the Jesuits. A very frequently used approach when the purpose is to decimate the identity of the peoples: erase both the oral as well as the written memory, and also their architetural memory. Th is paper attempts to rescue that memory so as to reveal the intentions of a human group that acted in a time that was unfavorable to the Jesuits.

PPARalpha agonists regulate lipid metabolism and nitric oxide production and prevents placental overgrowth in tern in placentas from diabetic rats Martinez, Nora Alicia; Kurtz, Melisa Lidia Amelia; Capobianco, Evangelina Lorena; Higa, Romina Daniela; White, Verónica; Jawerbaum, Alicia Sandra Maternal diabetes impairs fetoplacental metabolism and growth. Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor capable of regulating lipid metabolism and inflammatory pathways. In this study, we analyzed whether placental and fetal PPARα activation regulates lipid metabolism and nitric oxide (NO) production in term placentas from diabetic rats. Diabetes was induced by neonatal streptozotocin administration. On day 21 of pregnancy, placentas from control and diabetic rats were cultured in the presence of PPARα agonists (clofibrate and leukotriene B4 (LTB4)) for further evaluation of levels, synthesis, and peroxidation of lipids as well as NO production. Besides, on days 19, 20, and 21 of gestation, fetuses were injected with LTB4, and the placentas were explanted on day 21 of gestation for evaluation of placental weight and concentrations of placental lipids, lipoperoxides, and NO metabolites. We found that placentas from diabetic rats showed reduced PPARα concentrations. They presented no lipid overaccumulation but reduced lipid synthesis, parameters negatively regulated by PPARα activators. Lipid peroxidation and NO production, increased in placentas from diabetic rats, were negatively regulated by PPARα activators. Fetal PPARα activation in diabetic rats does not change placental lipid concentrations but reduced placental weight and NO production. In conclusion, PPARα activators regulate lipid metabolism and NO production in term placentas from diabetic rats, an activation that regulates placental growth and can partly be exerted by the developing fetus.

Problemáticas socioambientales producidas por el avance de urbanizaciones sobre producciones intensivas del periurbano de Buenos Aires Feito, Maria Carolina Analizamos la dimensión socioambiental de ciertos conflictos desencadenados por la instalación de barrios residenciales en ámbitos tradicionalmente rurales del periurbano de la Ciudad de Buenos Aires. Tomamos el caso de la producción intensiva de aves, en la juridiscción de Exaltación de la Cruz, en la zona Norte del periurbano mencionado, en donde nuevas formas de uso del espacio rural basadas en aspectos residenciales, implican una mercantilización de lo rural, produciendo un aumento de heterogeneidad del espacio rural mediante instalación de countrys en una zona con fuerte revalorización inmobiliaria, que compite con la tradicional actividad avícola. Estos avicultores entran en conflicto por uso del espacio rural con los nuevos vecinos que los acusan de supuesta “contaminación ambiental”. Considerando que los problemas ambientales no son "naturales" sino que se originan en fenómenos de distintos tipos: naturales (medio físico); sociales (relaciones entre los hombres); antrópicos (actividad humana), mostramos que las distintas percepciones que las personas tienen sobre el medioambiente y los riesgos ambientales que corren, varían según los contextos culturales en donde los peligros percibidos tienen lugar. En este marco, el municipio de Exaltación intenta crear nuevas regulaciones e instancias de concertación para participación consensuada entre distintos actores, para promover la convivencia de distintas ruralidades en el partido. El desarrollo local puede articular la reconstrucción y compensación de los daños con el debate acerca de la gestión ambiental y la toma de decisiones participativas.

El valor económico de la información climática; The economic value of climate information Bert, Federico Esteban; Letson, David; Podesta, Guillermo

Effect of lithium on the electrical properties of polycystin-2 (TRPP2) Cantero, Maria del Rocio; Cantiello, Horacio Fabio Polycystin-2 (PC2, TRPP2) is a TRP-type, non-selective cation channel whose dysfunction is implicated in changes in primary cilium structure and genesis of autosomal dominant polycystic kidney disease (ADPKD). Lithium (Li+) is a potent pharmaceutical agent whose effect on cell function is largely unknown. In this work, we explored the effect of Li+ on PC2 channel function. In vitro translated PC2 was studied in a lipid bilayer reconstitution system exposed to different chemical conditions such as Li+ or K+ chemical gradients and different symmetrical concentrations of either cation. Li+ inhibited PC2 function only from the external side, by decreasing the single-channel conductance and modifying the reversal potential consistent with both permeability to and blockage of the channel. When a chemical gradient was imposed, the PC2 single-channel conductance was 144 pS and 107 pS for either K+ or Li+, respectively. Data were analysed in terms of the Goldman–Hodgkin–Katz approximation and energy models based on absolute rate theory to understand the mechanism(s) of Li+ transport and blockage of PC2. The 2S3B model better explained the findings, including saturation, anomalous mole fraction, non-linearity of the current–voltage curves under bi-ionic conditions and concentration dependence of permeability ratios. The data indicate that Li+ modifies PC2 channel function, whose effect unmasks a high-affinity binding site for this ion, and an intrinsic asymmetry in the pore structure of the channel. The findings provide insights into possible mechanism(s) of Li+ regulation of ciliary length and dysfunction mediated by this cation.

Identidad y colonialidad en los relatos de Alberto Alabí; Identity and Coloniality in Alberto Alabí’s Short Stories López, Irene Noemí En este artículo proponemos un análisis de algunos relatos del escritor argentino Alberto Alabí desde la noción de colonialidad en sus tres dimensiones —del poder, del saber y del ser— y sus implicaciones en las formaciones identitarias. Consideramos que los conflictos que estos relatos textualizan nos permiten comprender algunas de las problemáticas sociales candentes en el espacio norteño, como la racialización de la diferencia y, consecuentemente, el color de piel, tanto en la subalternización de sujetos y prácticas como en la construcción de representaciones identitarias.; In this paper we propose an analysis of short stories of an argentinean writter, Alberto Alabí, from the notion of coloniality of power, of knowledge and being and its implications for identity formations. We believe that the conflicts textualized in these short stories permit us to understand many of social problems in the north of Argentina, such as the role played by the racialization of difference and, consequently, the color of skin in the subalternization of subjects and practices as well as in construction of identity representations.