Application of quantitative structure-property relationship analysis to estimate the vapor pressure of pesticides Goodarzi, Mohammad; Coelho, Leandro dos Santos; Honarparvar, Bahareh; Ortiz, Erlinda del Valle; Duchowicz, Pablo Román The application of molecular descriptors in describing Quantitative Structure Property Relationships (QSPR) for the estimation of vapor pressure (VP) of pesticides is of ongoing interest. In this study, QSPR models were developed using multiple linear regression (MLR) methods to predict the vapor pressure values of 162 pesticides. Several feature selection methods, namely the replacement method (RM), genetic algorithms (GA), stepwise regression (SR) and forward selection (FS), were used to select the most relevant molecular descriptors from a pool of variables. The optimum subset of molecular descriptors was used to build a QSPR model to estimate the vapor pressures of the selected pesticides. The Replacement Method improved the predictive ability of vapor pressures and was more reliable for the feature selection of these selected pesticides. The results provided satisfactory MLR models that had a satisfactory predictive ability, and will be important for predicting vapor pressure values for compounds with unknown values. This study may open new opportunities for designing and developing new pesticide.

La industria argentina de harina de trigo en el cambio de siglo: Límites y alcances, 1880-1914; Flour milling industry in Argentina at the turn of the century: Limitations and scopes, 1880-1914 Martiren, Juan Luis; Rayes, Agustina La expansión agraria producida en la región pampeana entre el último cuarto del siglo XIX y las dos primeras décadas del XX, convirtió a este espacio en uno de los mayores nichos productores de cereales del mundo. Como corolario, este proceso permitió la emergencia de una industria harinera que en pocos años acaparó los mercados nacionales y se posicionó fuertemente en las plazas de abasto brasileñas. No obstante, para ingresar a este mercado las harinas argentinas debieron enfrentar constantemente fuertes restricciones arancelarias, lo cual, según la bibliografía especializada, supuso un importante freno a la expansión de esta industria. En este trabajo proponemos revisitar esa imagen, al presentar evidencia estadística seriada sobre índices de producción, precios y comercio exterior del producto, con el fin de mostrar, además de la evolución creciente de la industria, que el peso de las exportaciones ha sido sobrevalorado en la bibliografía.; The agrarian expansión in the Pampean region between the last quarter of the XIXth century and the first two decades of the XXth transformed this area in one of the largest world’s cereal production cores. As a result, this process allowed the emergence of a flour milling industry that readily garnered national and Brazilian markets. However, to enter into them, Argentine flour faced tariff restrictions, wich, according to the literature, was a major obstacle to the expantion of this industry. In this paper we propose to revisit that image, presenting statistical evidence on serial production rates, prices and foreign trade of the product, in order to show the the weight of exports has been overrated in this literature.

Second-order magnetic critical points at finite magnetic fields: Revisiting Arrott plots Bustingorry, Sebastián; Pomiro, Fernando; Aurelio, Gabriela; Curiale, Carlos Javier The so-called Arrott plot, which consists in plotting H/M against M2, with H the applied magnetic field and M the magnetization, is used to extract valuable information in second-order magnetic phase transitions. Besides, it is widely accepted that a negative slope in the Arrott plot is indicative of a first-order magnetic transition. This is known as the Banerjee criterion. In consequence, the zero-field transition temperature T∗ is reported as the characteristic first-order transition temperature. By carefully analyzing the mean-field Landau model used for studying first-order magnetic transitions, we show in this work that T∗ corresponds in fact to a triple point where three first-order lines meet. More importantly, this analysis reveals the existence of two symmetricalsecond-order critical points at finite magnetic field (Tc,±Hc). We then show that a modified Arrott plot can be used to obtain information about these second-order critical points. To support this idea we analyze experimentaldata on La2/3Ca1/3MnO3 and discuss an estimate for the location of the triple point and the second-order critical points

Programación de la producción a corto plazo y de tareas de mantenimiento preventivo en ambientes Job Shop Flexibles Sirolla, Mauricio Daniel; Novas, Juan Matias; Henning, Gabriela Patricia Se aborda el problema de scheduling predictivo en plantas industriales de tipo Job Shop Flexible para el que se ha desarrollado un modelo basado en programación con restricciones (Constraint Programming, CP) que permite obtener una agenda eficiente para un conjunto de partes o Jobs conocido de antemano. El modelo considera las características de este tipo de ambiente industrial: recetas de manufactura específicas para cada Job, unidades multipropósito y disímiles para llevar a cabo cada operación, tiempos de alistamiento de equipos y de disponibilidad inicial de las máquinas, etc. Además, la formulación considera la necesidad de ejecutar tareas de mantenimiento preventivo en cada equipo. El modelo se ha verificado y validado utilizando diferentes ejemplos de tamaño medio disponibles en la bibliografía, hallándose soluciones de muy buena calidad en bajos tiempos de cómputo, lo que permite inferir las bondades del modelo.

Epipelon dynamics in a shallow lake through a turbid-and a clear-water regime Cano, Maria Gabriela; Casco, Maria Adela; Claps, Maria Cristina In Pampean lakes, very little information is available on epipelon structure and dynamics or the effect of environmental variables on those parameters. We anticipate that light may have the greatest influence on this community and that the nutrient concentration and substrate instability may exert secondary effects. Our objective was to analyze variations in descriptive parameters and in the algal species composition of the epipelon in the Pampean Lake Lacombe over space and time to establish the most influential environmental forces (light climate, wave action, nutrients). Sediment was collected from the benthos with a 3.5-cm-diameter corer in a year-round sampling every month at four sites in the lake that differed from each other in depth, distance from the shore, and the presence of emergent and submerged macrophytes. Although Lacombe is a shallow lake, differences occurred in community descriptive variables and in the epipelon composition (especially diatoms) over space and time. In particular, differences between the site nearest to the shore and the rest of the sites were found with respect to environmental variables (sediment-particle size, total phosphorus, organic matter content, light climate), epipelon descriptive parameters (abundance, chlorophyll a and Margalef’s index) and epipelon composition (especially specific biovolume and diatom-size classes). The epipelon also reflected, though slightly, the change from the turbid- to clear-water states in the lake. Sediment erosion or deposition was evidenced by differences in the sediment-particle composition and the predominant particle-size classes at each site. Statistical analyses indicated linear correlations between the epipelon parameters and variables related to the light climate in the water column. Conductivity and sediment total phosphorus and density were also correlated, but to a lesser extent, with epipelon composition. The epipelon variations in Lacombe Lake would exemplify the reference communities developed during clear or turbid regimes in Pampean shallow lakes. We found evidence for the influence of light climate and wave action (through instability of the substrate) on this community, but the effect of nutrients was negligible. We emphasize that the close relationships maintained by the epipelon with other communities such as the phytoplankton and the epiphyton may superimpose the patterns of variation to those communities onto the epipelon dynamics.

An index to evaluate the fluvial habitat degradation in lowland urbanstreams Cochero, Joaquin; Cortelezzi, Agustina; Tarda, Alan Santiago; Gomez, Nora The objective of the present article is to propose an index that allows the assessment of the fluvial habitat quality in lowland streams that run through urbanized areas, by the use of metrics related to the quality of the watercourse, the river banks, the riparian zone and the fluvial geomorphology. The metrics retained in the index (USHI, Urban Stream Habitat Index) include the cover percentage and quality of the aquatic vegetation; the main features of the river banks; the presence of exotic trees, of litter, of permanent structures (such as buildings) in the riparian zone and other major geomorphological alterations, such as dredging or channelization. The index is related to physical-chemical parameters that are linked to water quality, the imperviousness of the watershed and to other biotic descriptors, particularly the macroinvertebrate and diatom assemblages. The values of the index for the sites in the studied area revealed that 41.2% have a bad or very bad habitat quality, 27.8% a moderate habitat quality, while 31% have a good or very good habitat quality. The main issue detected in the studied sites involved the dredging or partial channelization of the reaches. Unlike other indices that evaluate the quality of the physical habitat through the use of the diatoms or macroinvertebrate communities, the USHI can be interpreted as a measure of the overall quality of the habitat, and uses indicators that do not require the identification of taxa, making it more accessible to non-specialists. Therefore it provides with a tool to evaluate the fluvial habitat quality of lowland streams that can be easily applied, particularly by professionals that take part in the management and decision making process regarding urbanized watersheds.

Family Ceratopogonidae Spinelli, Gustavo Ricardo; Wolff, Marta Two hundred and thirty five species of Ceratopogonids arranged in 28 genera are listed for Colombia, mostly Culicoides (112 species) and Forcipomyia (50 species). For each listed species, information on type locality, type category and sex, location of type material, species distribution, localities for Colombia and main references, is provided. Localities are not
specified for 17 species in which the literature searching was negative. Forcipomyia squamitibia Lutz and Bezzia clavipennis are excluded from the list.

Altered soil carbon dynamics under different land-use regimes in subtropical seasonally-dry forests of central Argentina Conti, Georgina; Kowaljow, Esteban; Baptist, Florence; Rumpel, C.; Cuchietti, Anibal; Pérez Harguindeguy, Natalia; Díaz, Sandra Myrna Background and aims Subtropical seasonally dry forestsfrom South America are now experiencing one ofthe highest rates of forest-cover change globally. Thesechanges may affect the dynamics of soil organic carbon(SOC) including long-term stabilization processes, withprofound consequences for the fertility and carbon storageof these ecosystems.Methods In order to explore the effect of different landuseregimes on SOC dynamics, we determined theamount and quality of plant litter, the amount and quality(lignin and carbohydrate content) of SOC, and thesoil basal respiration rates across seasonally dry Chacoforests of Argentina.Results Changes in land-use regimes significantly reducedthe amount of litter but not its quality. As aconsequence, the SOC content was also reduced togetherwith SOC quality. Unexpectedly, we found a higherCO2 release per SOC unit in soils with lower amountand quality of SOC.Conclusions The results presented here show a cleareffect of different land-use regimes on SOC dynamicsthrough a reduction in the amount and quality of SOC.Additionally, we found that potential microbial activityis somehow disconnected from substrate quantity andquality, suggesting that the molecular structure of SOCis not significantly affecting long-term soil stabilizationprocesses across these seasonally-dry ecosystems.

La integración entre la espiritualidad Nueva Era y el Nuevo Management en Argentina: afinidades y tensiones Funes, María Eugenia A pesar de su creciente impacto en los diferentes ámbitos de la vida cotidiana, las prácticas y disciplinas espirituales han sido especialmente estudiadas por su incidencia en la salud, lo terapéutico y lo religioso, dejando de lado otros ámbitos relevantes como la educación, la política y la economía. La influencia de la espiritualidad en ésta última cuenta con numerosas expresiones, entre ellas la incorporación técnicas y discursos espirituales a las políticas de gestión del trabajo por parte de las empresas. En este artículo nos proponemos explorar la integración del marco interpretativo de la espiritualidad Nueva Era al management. Para ello analizaremos la puesta en escena y los discursos pronunciados durante una serie de conferencias que tienen como objetivo promover el desarrollo holístico de individuos y grupos en sus lugares de trabajo. Estas exposiciones son dictadas por empresarios y líderes de ONGs vinculados a la espiritualidad, así como por líderes de organizaciones espirituales; y se orientan a un público formado por empresarios, ejecutivos y empleados de áreas de recursos humanos de grandes empresas argentinas.

El pasado argentino en disputa: peronismo y antiperonismo en la interpretación de la historia de la provincia de Corrientes; The Argentine past in dispute: peronism and anti-peronism in the interpretation of the history in the province of Corrientes Solís Carnicer, María del Mar Las diversas interpretaciones del pasado y sus héroes tienen una función de legitimación de las prácticas políticas del presente y, por ello, se convierten en uno de los espacios de la disputa política. La Argentina peronista no fue ajena a estas prácticas y también se preocupó de construir una tradición histórica en la que apoyarse. Con el análisis de la situación de la provincia de Corrientes, en este artículo estudiamos el modo en que los usos del pasado ayudaron a articular la relación oficialismo-oposición en ese periodo.; Interpretations and heroes of the past have a function of legitimization of policies in the present, taking part with it in the current political controversies. Argentina in Peronist period was not immune to these practices and also attempted to build up a historical tradition to be based upon. Dealing with the situation in the province of Corrientes, in this article we shall examine the way in which the uses of the past marked the relationship between the ruling party and the opposition in that period.

Application of a new rheological model to rock avalanches: an SPH approach Manzanal, Diego; Drempetic, V.; Haddad, B.; Pastor, M.; Stickle, M. Martín Rock avalanches move large volumes of material causing a highly destructive power over large areas. In these events, it is possible to monitor the evolution of slopes but failure cannot be always prevented. For this reason, modelling of the propagation phase provides engineers with fundamental information regarding speed, track, runout and depth. From these data it is possible to perform a better risk assessment and propose mitigation measures to reduce the potential hazard of specific area.The purpose of this paper is to present a depth integrated, SPH model, which can be used to simulate real rock avalanches and to assess the influence of the rheology on the avalanche properties. The paper compares the performance of different rheological models to reproduce the track, runout and depth of the final deposit for both, scale test and real events such as Frank and Thurwiesier rock avalanches. These sets of benchmarks provide information on the proposed model accuracy and limitations.

Processing–properties–applications relationship of nanocomposites based on thermoplastic corn starch and talc Lopez, Olivia Valeria; Castillo, Luciana Andrea; Barbosa, Silvia Elena; Villar, Marcelo Armando; Garcia, Maria Alejandra Films based on thermoplastic corn starch (TPS) and talc nanoparticles were developed by melt mixing and thermo-compression. Films structure, optical and barrier properties, as well as thermal stability and water sorption behavior were studied. TPS structure resulted homogeneous and smooth. Talc laminar morphology and thermo-compression induced particle preferential orientation within the matrix. Good particle distribution and talc-TPS adhesion were evidenced. Nanometric thickness of mineral particles allowed obtaining translucent composite films, without significant color variation of TPS films. Talc addition at concentrations higher than 3% w/w led to an improvement on TPS barrier properties against water vapor and oxygen. It was also demonstrated that talc decreased water uptake of TPS films exposed to ambient conditions with relative humidity higher than 40%. In conclusion, films based on TPS and talc nanoparticles could be an alternative to develop biodegradable packages for food products with suitable final properties.

Argumentación y tópoi retóricos: Aplicaciones teórico metodológicas al discurso de la (in)seguridad en la prensa gráfica argentina Sánchez, María del Rosario Este artículo propone una reflexión acerca del alcance del análisis del discurso para dar cuenta de diversas problemáticas sociales, políticas e ideológicas. Con este fin, aplica algunas herramientas teórico-metodológicas del campo disciplinar a un estudio de caso, el discurso de la denominada “inseguridad” en la prensa gráfica argentina. La propuesta es identificar y explicar los tópoi retóricos que el diario La Nación moviliza en su discurso argumentativo (género editorial) con el fin de sostener una posición particular en un conflicto suscitado en torno a la problemática mencionada. En esta línea, se analizan ciertas modalidades a través de las cuales este discurso busca construir consenso y polemizar con un adversario, considerando, a su vez, las relaciones que mantiene con un contexto histórico y sociopolítico específico y una doxa particular, como condiciones de posibilidad para su emergencia. En este punto, proponemos que el núcleo polémico puesto en juego en el discurso forma parte de una lucha política ideológica más amplia entre diversos actores en torno a la seguridad como macroproblema y al orden social anhelado.; This article proposes a reflection on the scope of discourse analysis to account for diverse social, political and ideological issues. In order to achieve this goal, we apply theoretical and methodological tools of the field to a case study, the discourse on “insecurity” in the Argentinean press. We propose to identify and explain the rhetorical tópoi staged by the newspaper La Nación in its argumentative discourse (editorial genre) in order to hold a particular position on the issue mentioned above. The article analyzes some forms by which this discourse seeks to build consensus and argue with an opponent, considering also its relationships with a specific historical and political context and a particular doxa, as enabling conditions for its emergence. At this point, we propose that the controversial core developed in the discourse is part of a broader ideological and political dispute among diverse actors around security as a macro problem and the expected social order.

Effect of tannins on survival and development of Daphnia menucoensis and the abundances of bacteria Alvarez, María Fernanda; Benitez, Hernan Hugo; Villegas Cortés, J. Camilo; Gabellone, Nestor Adrian; Claps, Maria Cristina Polyphenols – products of organic-matter decomposition entering water bodies from autochthonous and especially allochthonous sources – affect primary producers, bacterioplankton, and zooplankton to consequently modify food webs. Cladocerans are widely used in research experiments because they constitute the most frequent prey of high-trophic-level organisms in the majority of lakes, and certain species symbolise the ecologic prototype of the generalist filter feeder. In our study area’s shallow lakes, cladocerans, though generally of low abundance, do attain significantly high biomasses. We accordingly evaluated the mortality of the cladoceran Daphnia menucoensis Paggi, 1996 exposed to different tannin concentrations along with the bacterial abundance. In two experiments D. menucoensis females exposed to high tannin concentrations reproduced inefficiently, exhibited high mortality, and manifested altered behaviour, such as reduced reflexes and diminished mobility. Though tannins apparently affected algal abundances, the cladoceran herbivory strongly reduced those numbers. Positive effects on bacteria, however, were not recorded. High-allochthonous-organic-matter-containing water bodies support trophic webs because bacterioplankton provide an alternative energetic base for the zooplankton, as possibly occurs in shallow lakes of the Salado-River basin, characterised by cyclic hydrologic periods alternating between draught and flooding and intensive land use. In conclusion, tannins diminish D. menucoensis’s survival, locomotion, and the capacity to respond to stimuli.

Posicionamientos ideológicos de quienes se ubican en el "centro" o “no poseen ideología”; Ideological positionings of people who self-define as "center" or “not possessing ideology” Brussino, Silvina Alejandra; Imhoff, Débora Soledad; Alonso, Daniela Rocío Estetrabajo intenta aportar a la comprensión de los posicionamientos ideológicos deciudadanos que no se auto-ubican en el espectro ideológico (porque no pueden oeligen no hacerlo) o que se posicionan en el "centro". Se efectuó un estudio cuantitativo con dos muestras de ambos sexos: estudiantes universitarios y población general.Se aplicó un cuestionario cerrado que indagaba variables socio-demográficas, auto-posicionamiento ideológico y posicionamientos ideológicos ante tópicos situacionales (seguridad, drogas, aborto, economía, democracia, entre otros). Se efectuaron Análisis de Varianza para conocer las diferencias entre los grupos en cuanto a sus posicionamientos. Los resultados indican perfiles diferenciales entre los grupos, y ratifican que estas personas detentan posiciones ideológicas conservadoras y progresistas aunque simbólicamente no se identifiquen ni con la izquierda ni con la derecha. En función de los resultados, se discute acerca dela utilidad de trascender el análisis de la ideología política centrado exclusivamente en su dimensión simbólica, avanzando hacia mediciones operativas de la ideología política de la ciudadanía.

Draft whole-genome sequence of Sphingobium sp. 22B, a polycyclic aromatic hydrocarbon- degrading bacterium from semiarid Patagonia, Argentina Madueño, Laura; Macchi, Marianela; Morelli, Irma Susana; Coppotelli, Bibiana Marina Sphingobium sp. 22B is a polycyclic aromatic hydrocarbon-degrading strain isolated from Patagonia, Argentina, with capabilities to withstand the environmental factors of that semiarid region. The draft genome shows the presence of genes related with responses to carbon starvation and drying environmental conditions.

Propuestas para el estudio y caracterización de los pequeños productores agropecuarios de la puna jujeña (Argentina); Proposals for the study and characterization of small agricultural producers in the puna of Jujuy (Argentina) Bergesio, Liliana del Carmen; Golovanevsky, Laura Andrea; González, Natividad María En este trabajo se enfoca el análisis en los pequeños productores de la puna jujeña (extremo noroeste de la República Argentina) para reflexionar, primero, acerca de la complejidad de abordar su estudio, tanto por la ambivalencia de su conceptualización como por la falta de información pertinente, para luego proponer acciones que apunten a superar estas limitaciones. Para ello, en primer lugar, se discute la categoría de pequeños productores, para después avanzar en la construcción de una definición de pequeños productores agropecuarios en el contexto de la puna jujeña. En segundo lugar, sobre la base de esta definición, se observará cuáles son las fuentes secundarias a las que se puede recurrir para su caracterización y descripción, destacando sus alcances y límites. En tercer lugar, y en base a lo anterior, se plantea una propuesta conceptual y metodológica para encarar el estudio de los pequeños productores agropecuarios para el caso de la puna de Jujuy, tendiente a superar los déficits identificados previamente.; This article focuses on the analysis of small producers in Jujuy´s puna (northwestern of Argentina), firstly to think about the complexity of its study, both because of the ambivalence of its conceptualization and the lack of pertinent information, and in the second place to propose actions aimed to overcome this limitations. With this objective the notion of small producers is discussed in the first place, to advance in the building of a definition of small agricultural and livestock producers in the context of Jujuy´s puna. Secondly, based on this definition, the secondary fonts to which turn to for its characterization and description will be observed, emphasizing their scopes and limitations. Thirdly, based on the previous analysis, a conceptual and methodological proposal is set out to aim at the study of small agricultural and livestock producers in the case of Jujuy´s puna, tending to overcome the deficits previously identified.

Procesos de recuperación y negación de la voz filial en las poéticas de hijos de desaparecidos. La colección de poesía Los Detectives Salvajes. Tavernini, Emiliano La colección Los Detectives Salvajes fue creada en 2007 y reúne a poetas desaparecidos, asesinados durante el terrorismo de estado de la última dictadura militar argentina o en la etapa previa, bajo el accionar de la Triple A; así también como a sus hijos. En esta operación cultural se ponen en escena los diálogos entre las obras monumentarias, recuperadas del olvido por los editores, insertas en un campo cultural diferente, y las nuevas voces de la poesía. Por otra parte, los debates que se generan a partir de las publicaciones de la editorial pueden interpretarse desde la perspectiva de Alain Badiou (2005): ¿es urgente representar a las víctimas o ser fiel a los acontecimientos en los que esas víctimas se pronuncian?, pregunta que atravesaría e interpelaría a cada uno de los poetas “hijos” de la colección. En las manifestaciones artísticas de hijos de desaparecidos, se efectúen éstas en soporte fotográfico, cinematográfico o narrativo, es habitual un procedimiento de composición que tiende a visibilizar procesos a través de los cuales se produce un diálogo necesario que implica la recuperación o restitución de la imagen o la voz de los padres, pero que simultáneamente pone de manifiesto una brecha que los distancia política, estética y generacionalmente. Me interesa analizar de qué modo se desarrollan estos procesos en la colección de poesía Los Detectives Salvajes y en un caso particular del catálogo que condensa en varios puntos la singularidad de la poesía de los “hijos”, el poemario ylumynarya de Julián Axat, director junto con Juan Aiub de la colección de la editorial platense Libros de la Talita Dorada.

Pardeamiento enzimático: caracterización fenotípica, bioquímica y molecular en variedades de papa nativas de la Argentina; Enzimatic browning: phenotypic, biochemical and molecular characterization of native potatoes from Argentina Suarez, Patricia Alejandra; Andreu, Adriana Balbina; Colman, Silvana Lorena; Clausen, Andrea Martina; Feingold, Sergio El pardeamiento enzimático (PE) esta relacionado con la actividad de la enzima polifenol oxidasa (PPO) que cataliza la oxidación a diferentes compuestos fenólicos, con la consecuente transformación a pigmentos oscuros no deseables para la calidad industrial. Este trabajo contribuye a la caracterización del PE en papas nativas (Solanum tuberosum ssp. andigenum) a través de la determinación de la variabilidad alélica de los genes de PPO, la actividad enzimática relacionada y la resultante calidad industrial por medio de parámetros cualitativos. En los 20 genotipos estudiados se encontraron diferencias significativas en la actividad de PPO y el índice oxidativo (IO), lo que permitió distinguir individuos con mejor comportamiento frente al PE. Asimismo, se observó variabilidad genética en las regiones amplificadas de los genes de PPO identificándose 9 posibles variantes alélicas. Hasta el momento no se pudo establecer asociación entre bandas y la actividad de PPO o IO, posiblemente debido a factores ambientales que pudieron haber incidido durante el desarrollo del cultivo y/o al número reducido de genotipos estudiados a la fecha.; Enzymatic browning (EB) is related to polyphenol oxidase (PPO) activity, which catalyzes the oxidation of various phenolic compounds that renders dark pigments which are undesirable for industrial quality of potato. This study contributes to the characterization of EB in native potatoes (Solanum tuberosum ssp. andigenum) through the analysis of allelic variability in PPO genes, the determination of the enzymatic activity and the resulting darkening of tubers through qualitative parameters. Variability was found among 20 selected genotypes in activity of PPO and oxidative index (OI), which allowed distinguishing individuals with better EB performance. Also, genetic variability was observed in the amplified regions of PPO genes, which shown 9 possible allelic variants. However, no clear association was found between putative alleles and PPO activity or OI .This lack of association can be related to the reduced number of genotypes assayed up to date and/or environmental factors that could have influenced tuber production.

Isótopos estables y dieta de los cazadores recolectores del sudoeste bonaerense (Argentina); Stable isotopes and diet of hunters gatherers of southwest of Buenos Aires province (Argentina) Scabuzzo, Clara; Frontini, Romina; Vecchi, Rodrigo Javier; Bayón, María Cristina Se presentan los primeros resultados del análisis de isótopos estables (δ13C y δ15N) obtenidos sobre restos humanos provenientes de sitios arqueológicos del sudoeste de la provincia de Buenos Aires (Argentina), datados en el Holoceno Tardío. Conjuntamente se informan los primeros datos de δ13 Ccol. sobre los distintos recursos faunísticos del sector.El área de estudio se compone de diversos ambientes, destacándose los entornos acuáticos como la costa marina, los valles fluviales, las lagunas y el humedal. Los valores isotópicos de los recursos del sector indican que los animales marinos presentan los valores más enriquecidos en 13C; mientras que aquellas especies terrestres (coipo, ñandú y herbívoros grandes) presentan los valores más empobrecidos, que son indistinguibles entre ellos. Por su parte, las aves acuáticas y el peludo tienen valores intermedios. El estudio isotópico sobre restos humanos reflejó que la dieta de los individuos fue cárnica, que las proteínas de animales terrestres fueron predominantes y que en menor proporción se usaron recursos marinos. El registro arqueofaunístico del área resulta concordante con esta información. Finalmente, estos son los primeros resultados isotópicos para el sector, por lo que constituye un aporte preliminar que deberá continuar con la realización de nuevos estudios.; Results of the first stable isotopes analysis (δ13C and δ15N) of archaeological sites located in the southwest of the province of Buenos Aires (Argentina) are presented. Both the construction of an isotopic ecology and prehistoric human diets of the sector are explored. The isotopic ecology indicates diverse environments in which marine animals have enriched δ13Ccol. values; while terrestrial species such as coypo, greater rhea and large-sized herbivores have the poorest values that are indistinguishable among the different taxa. Furthermore, ducks and a hairy armadillo showed intermediate values. Human isotopic values indicate a diet based on the consumption of meat. These proteins came predominantly from terrestrial animals complemented by marine resources. The local archaeological record is consistent with this information, as the main faunal resources are terrestrial species; nevertheless a scarce representation of marine fauna, mainly Otariids, is registered. In this paper we present the first isotopic values for the studied area and thus it is a preliminary contribution that must be further investigated with new samples.