Mesotheriid (Mammalia, Notoungulata) remains from the Colhuehuapian beds (Early Miocene) of Chichinales Formation, Río Negro Province, Argentina Paz, Ernesto Rodrigo; Kramarz, Alejandro Gustavo; Bond, Mariano The Mesotheriidae represent one of several clades of the endemic South American ungulate Order †Notoungulata. This clade has some rodent-like adaptations such as hypertrophied upper and lower incisors, highly hypsodont cheek teeth, reduced dental formula (in younger forms), simplified occlusal morphology, and specialized zygomasseteric structure, among other features (Patterson, 1934; Billet et al., 2008). Traditionally, the Mesotheriidae have been divided into two subfamilies: Trachytheriinae and Mesotheriinae (Simpson, 1945). Recent phylogenetic analyses supported the monophyly of Mesotheriinae, but indicated that Trachytheriinae is a paraphyletic assemblage of basal mesotheriids (Cerdeño and Montalvo, 2001; Croft et al., 2004; Reguero and Castro, 2004; Billet et al., 2008).

Development of a highly specific ensemble of topological models for early identification of P-glycoprotein substrates Di Ianni, Mauricio Emiliano; Talevi, Alan; Castro, Eduardo Alberto; Bruno Blanch, Luis Enrique P-glycoprotein (Pgp) is an ATP-dependent efflux transporter protein associated with multidrug resistance in several diseases such as cancer, epilepsy and AIDS. It is preferentially expressed in organs and tissues that function as a barrier (e.g. the gut walls or the blood?brain barrier) or promote the elimination of xenobiotics from the organism (e.g. liver and kidney). Pgp limits drug bioavailability; thus, the recognition of Pgp substrates at the early stages of the drug development cycle is essential for the development of new chemotherapeutic agents to deal with multidrug resistance issues. Here we present the development of several classifier models based on topological descriptors to identify potential Pgp substrates, aimed to be applied as secondary filter in virtual screening campaigns. Receiver Operating characteristic (ROC) curves show that combination of individual models, through data fusion, in a three-model ensemble, allows attaining higher areas under the curve and an overall better behavior in terms of sensitivity or specificity. The individual discriminant functions (dfs) presented have a performance similar to that of the previously reported models and, remarkably, our models only include low-dimensional (up to 2D) molecular descriptors, which makes them adequate for the virtual screening of increasingly large virtual chemical repositories.

Marine vertebrate assemblages in the southwest Atlantic during the Miocene Cione, Alberto Luis; Cozzuol, Mario Alberto; Dozo, Maria Teresa; Acosta Hospitaleche, Carolina Ileana Alicia Two biogeographical units are generally recognized in the present shelf area of Argentina: the Magellanian andArgentinian Provinces. The two provinces differ in their fossil record. The evolution of these provinces has beencharacterized by migrations, extinctions, pseudoextinctions and, perhaps, even speciation events. Marine vertebrateassemblages with some similarities to the Argentinian fauna were already present in the Miocene, whereasno associations similar to those of the Magellanian fauna have been found in South America before the Pleistocene.Two successive major marine transgressions flooded northern Patagonia during the Miocene: the ‘Patagoniense’(Early Miocene) and the ‘Entrerriense’ (Middle to Late Miocene). We analyse three rich fossil assemblages thatwere formed during these transgressions. The absence of Magellanian Miocene vertebrate assemblages is consistentwith the hypothesis of a more southern distribution of the cold-temperate fauna at that time. In Patagonia,as in other regions, an increased number of living groups appeared from the Lower to Upper Miocene. The LateMiocene aquatic mammals had a modern aspect, and some of the fish species are still living in the South AtlanticOcean. In this contribution, we stress that warm-temperate fishes and a high diversity of penguins are foundtogether at the base of the Gaiman Formation. We hypothesize that penguins were adapted to live in warmerwaters than those of the latest Cenozoic and the Recent. Finally, we recall that many taxa became extirpatedbecause of the global temperature drops of the late Cenozoic.

Pharmacocinétique et biodisponibilité de fosfomycine chez le poulet de chair; Pharmacokinetics and bioavailability of fosfomycin in broiler chicken Soraci, Alejandro Luis; Pérez, Denisa Soledad; Tapia, Maria Ofelia; Martinez, Guadalupe; Dieguez, Susana Nelly; Buronfosse Roque Florence; Harkes, Roberto; Colusi, A.; Romano Omar La pharmacocinétique et biodisponibilité de deux formulations de fosfomycine (fosfomycine disodique et fosfomycine calcique) ont été étudiées chez le poulet de chair. Les concentrations plasmatiques de fosfomycine ont été mesurées par chromatographie liquide haute performance (HPLC) couplée à une spectrométrie de masse en tandem (HPLC – SM/SM). Après administration d’un bolus intraveineux, la demi-vie d’élimination chez le poulet de chair est environ 1,4 h et le volume de distribution 231 ml/kg. Après absorption de fosfomycine par voie orale les valeurs de Cmax, Tmax, AUC(0-24) et biodisponibilité (F) sont respectivement 29,8 µg/ml, 2,0 h, 125 µg.h/ml et 39,3 %. Après l’administration par voie intramusculaire, les valeurs obtenues sont 20,7 µg/ml, 0,8 h, 65,1 µg.h/ml et 82 % pour la Cmax, Tmax, AUC(0-24) et biodisponibilité (F) respectivement. En considérant une CIM90= 8 µg/ml pour la fosfomycine sur des souches de E.coli chez le poulet de chair, les rapports AUC0-24/CMI90 calculés pour la fosfomycine administrée par voie orale et intramusculaire sont de 15,6 et 8,1 ce qui suggère une efficacité thérapeutique insuffisante in vivo lors d'une administration unique. Pour cette raison, il a été récemment proposé d’utiliser sur des souches sensibles de E.coli, une dose orale de charge de 40 mg/kg de fosfomycine disodique administrée dans l'eau de boisson, suivie d'une nouvelle administration de 40 mg/kg 8 h plus tard (soit 80 mg/kg par jour).; The pharmacokinetics and the bioavailability of fosfomycin salts (sodium fosfomycin and calcium fosfomycin) were studied in broiler chickens after intravenous, intramuscular and oral administration. Plasma concentrations were measured by high performance liquid ms/ms. After IV administration the area under the fosfomycin concentration: time curve in plasma was AUC(0-24) of 318 µg.h/ml and the volume of distribution (Vd) of 231 ml/kg. The elimination was rapid with a plasma clearance of 115 ml/kg/hr and a T1/2 of 1.4 h. Peak plasmatic concentration (Cmax), Tmax, AUC(0-24) and bioavailability for the oral administration (40 mg/kg) were 29.8 µg/ml, 2.0 h, 125 µg.h/ml and 39.3% respectively. Peak plasmatic concentration (Cmax), Tmax, AUC(0-24) and bioavailability for the IM administration (10 mg/kg) were 20.7 µg/ml, 0.8 h, 65.1 µg.h/ml and 82% respectively. Considering a minimum inhibitory concentration (MIC90) of 8 µg/ml for fosfomycin on E.coli in broilers, the ratios AUC0-24/CMI90 estimated for fosfomycin after oral and IM administrations were 15.6 and 8.1 respectively. This suggests an insufficient therapeutic efficacy in vivo when administered in a unique dose. For this reason, a loading dose of 40 mg/kg via drinking water has been recently proposed for disodium fosfomycin versus E. coli strains, followed by ad libitum administration of 40 mg/kg 8h later (i.e. 80 mg/kg per day).

Internacionalización del proceso productivo: Una reseña sobre la literatura especializada Lucanera, Romina Anahí; González, Germán Héctor El fenómeno de la globalización, apoyado por el desarrollo tecnológico y constantes procesos de integración al mundo de multitud de países, ha generando un entorno económico y empresarial más complejo que lleva a considerar la internacionalización como una estrategia factible. Se presenta una reseña de la literatura especializada y comentarios referidos a la necesidad de amplificar los esfuerzos en el estudio de las experiencias de internacionalización en América Latina y el Caribe.; The globalization phenomenon together with the technological development and the permanent integration process of a multitude of countries, have generated a more complex management environment where de internationalization is a feasible strategy We present a review of the literature and some comments about the need to amplify the efforts in the study of the internalization process of the firm in Latin America and the Caribbean.

Organochlorine compound residues in the eggs of broad-snouted caimans (Caiman latirostris) and correlation with measures of reproductive performance Stoker, Cora; Repetti, María Rosa; García, S.R.; Zayas, Marcelo Alejandro; Galoppo, Germán Hugo; Beldoménico, H.R; Luque, Enrique Hugo; Muñoz de Toro, Monica Milagros Organochlorine compounds (OCCs), like pesticides (OCPs) and polychlorinated biphenyls (PCBs), are persistent lipophilic chemicals classified as endocrine-disruptors. Caiman latirostris inhabits wetlands throughout north-eastern Argentina and may accumulate OCCs. The aims of this study were to determine OCC residues in the eggs of C. latirostris and to correlate OCC burden with clutch size, hatching success and hatchling survival as measures of reproductive performance. Fourteen caiman clutches were harvested from sites with different degrees of anthropogenic intervention on wetlands surrounding Paraná River tributaries. Two to four eggs by clutch were used to quantify OCCs. OCP residues were found in all clutches. The principal contributors to the OCPs burden were the DDT family (range BDL-153.0ngg-1 lipid) and oxychlordane (range BDL-34.3ngg-1 lipid). PCBs were present in 92.9% of the clutches (range BDL-136.6ngg-1 lipid). Both higher concentrations and higher diversity of pesticides, including endosulfan sulfate, were found in the nests harvested close to croplands. A negative correlation was found between clutch size and ∑OCCs (p=0.02, Pearson r=-0.53, r2=0.28), mainly due to the ∑OCPs (p=0.04, Pearson r=-0.54, r2=0.30). Since egg OCCs concentrations predict maternal burden, present findings suggest that higher OCCs exposure could lead to smaller clutches. Although, other factors like mother age could influence clutch size. Additionally, as caimans are a long-lived and non-migratory species, the maternal OCCs burden reflects the environmental status throughout their home range; thus, caiman eggs could be useful as a biomonitor of local contamination.

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.