La etnobotánica urbana como herramienta de identificación de NUS: experiencias desde el área metropolitana de Buenos Aires, Argentina Hurrell, Julio Alberto; Arenas, Patricia Marta; Puentes, Jeremías Pedro El Laboratorio de Etnobotánica y Botánica Aplicada (LEBA) desarrolla una línea de investigación,pionera en la Argentina, sobre etnobotánica urbana en el ámbito del Área Metropolitana de Buenos Aires, la más extensa y poblada del país. Estudia los conocimientos botánicos no tradicionales, a través de los productos que se expenden principalmente en tiendas de alimentos saludables (dieteticas), y los ligados a tradiciones de origen de dos segmentos de inmigrantes, chinos y bolivianos, que comercializan sus plantas y productos. En la actualidad, los estudios se centraron en la inmigración china reciente, de presencia conspicuaen la ciudad de Buenos Aires, concentrada en un sector del barrio de Belgrano, denominado "Barrio Chino", donde se desarrollan actividades culturales y comerciales, estas últimas en un circuito comercial conformado por cinco grandes supermercados, que introducen productos vegetales mayormente provenientes de China, aumentando la diversidad biocultural local de especies y conocimientos asociados. Desde hace poco más de una década los relevamientos en los supermercados se enfocaron en productos importados de China y Taiwán correspondientes a la Fitoterapia Tradicional China y en alimentos funcionales frescos, que se producen en huertos periurbanos, como hemos recientemente constatado, y se comercializan en el "Barrio Chino".

Situación de calle espacio público uso de drogas: una aproximación al problema Di Iorio, Jorgelina La situación de calle es una de las manifestaciones más extremas de la exclusiónsocial y constituye un problema que se da principal pero no exclusivamente, en lasgrandes ciudades. Las condiciones de vulnerabilidad que afectan a las personas ensituación de calle son determinantes para dejarlas por fuera del ejercicio de su ciudadanía, y las exponen a circunstancias permanentes de riesgo, en un espacio signadopor la marginación y la pobreza. La degradación de las condiciones de vida y la devastación subjetiva se combinan en estas personas en las que las coordenadas queorganizan la vida se han desorganizado.Se suele señalar que la característica distintiva del espacio público es su grado de accesibilidad o la posibilidad de su uso sin restricciones para cualquier persona, es decirel espacio público es el espacio de uso público y es el escenario de la interacción social.Ahora bien, para las personas en situación de calle, el espacio público adquiere un sentido diferente, en tanto que es el lugar donde desarrollan su experiencia vital. Sin embargo,no debe eludirse que esto no es resultado de elecciones personales, sino que la vida en lacalle responde a situaciones forzadas y refleja una clara vulneración de derechos

Historia, violencia y memoria en la construcción de identidades: desaparecidos y sobrevivientes de la última dictadura militar en espacios locales de la provincia de Buenos Aires Echeverria, Olga Ines; Bilbao, Lucas Matías Este artículo busca poner en discusión algunas perspectivas teóricas sobre el tema de la violencia y la construcción de las memorias colectivas e individuales y su influencia en la creación de las identidades de los/as detenidos desaparecidos/as y de los/as sobrevivientes, víctimas de la represión de la dictadura cívico militar impuesta en Argentina entre 1976 y 1983. Una vez establecidas estas premisas de tipo teórico y sus debates, el capítulo buscará exponer sobre la efectiva construcción de las identidades haciendo especial hincapié en la experiencia de algunos casos locales de la provincia de Buenos Aires en una mirada comparativa con la discursividad que se desarrolla a nivel nacional o general, sus puntos en común, sus tensiones y sus contradicciones. Desde un enfoque histórico, en términos metodológicos, se trabajará con entrevistas y análisis de discursos de textos académicos, políticos y periodísticos.

La experiencia en digitalización de colecciones fotográficas: del contenido iconográfico a los procesos sociales de producción, circulación y preservación de imágenes Di Salvo, Luciano Daniel En los últimos años las posibilidades tecnológicas asociadas a la digitalización de documentos abrieron un campo promisorio para la incorporación de novedosos corpus de fuentes históricas. Dentro de ellos, los archivos fotográficos procedentes de colecciones privadas, en particular los provenientes de individuos y/o familias ocuparon un lugar destacado. A partir del desarrollo de la experiencia de un programa de documentación digital originalmente denominado Fototeca Digital de Ciencias Humanas, acercaremos algunas consideraciones respecto de las potencialidades y obstáculos que la digitalización supone en el tratamiento de los documentos históricos. En particular se hará hincapié en las metodologías adoptadas en el proceso, en una primera etapa centrado en el contenido iconográfico de las fotografías, para pasar luego a un segundo momento en el que cobraron un rol central en el proyecto las ponderaciones de los procesos de producción, circulación y preservación como ejes de las modalidades de apropiación y significación social de las imágenes. Consideramos asimismo que este repaso por nuestra experiencia de trabajo aportará nuevos interrogantes respecto de la problemática asociada a los documentos digitales como sucedáneos o réplicas de los originales en el trabajo de digitalización de archivos históricos.

Riesgos psicosociales en el trabajo informático: Una propuesta para su abordaje Adamini, Marina Este capítulo se propone analizar las potencialidades y límites del concepto de “riesgos psicosociales en el trabajo” en el estudio de las condiciones laborales en el sector del software y servicios informáticos. El concepto alude a las problemáticas que afectan psicológicamente al trabajador en su entorno laboral, las cuales junto con las problemáticas físicas afectan articuladamente la integridad de su salud. Se trata de un concepto reciente, de origen francés, que comenzó a ser aplicado no sólo en el mundo académico sino también en estudios estadísticos y demandas sindicales. En Argentina, su difusión se dio a partir de su aplicación por parte del grupo de estudios del Dr. Julio Neffa, en articulación con sindicatos de diversos sectores productivos. A la luz de estos antecedentes buscamos indagar las posibilidades teóricas, metodológicas y empíricas de su aplicación en nuestra investigación actual, centrada en el caso de los trabajadores informáticos de Tandil. En términos metodológicos, realizaremos un análisis de contenido de estudios que aplicaron el concepto de “riesgos psicosociales en el trabajo” para ponerlos en diálogo con nuestro corpus empírico compuesto por entrevistas a trabajadores informáticos, delegados sindicales y empresarios, junto con estadísticas provenientes del OEDE (MTEySS), OED (Ministerio de Producción) y OPSSI (CESSI).

Construyendo puentes entre la escuela y la universidad: el caso del desencuentro entre españoles y andinos en América Amaya, Yesica; Datola, Carla; Godoy, Maria Elena Partiendo de una instancia de trabajo colaborativo impulsada por la Universidad Nacional del Centro de la Provincia de Buenos Aires (UNICEN) y la escuela secundaria Sagrada Familia de Tandil, emprendimos el desafío de elaborar una propuesta áulica orientada a analizar y abordar en forma crítica el proceso de Conquista y Colonización de América. A partir del diálogo entre ambas instituciones educativas nos propusimos problematizar el concepto de "descubrimiento de América" con el propósito de dar inicio a un proceso de debate y deconstrucción de aquellas representaciones sesgadas, parciales e incluso etnocéntricas que aún perviven y se materializan a través de efemérides, discursos, diseños curriculares e incluso libros de texto en el ámbito escolar. En el marco de este escenario, elaboramos una propuesta de trabajo de carácter interdisciplinario y crítico-reflexiva entre el proyecto “Aprender Enseñando” de la cátedra de Historia Americana II de la carrera de Historia y las docentes del Colegio Sagrada Familia. Desde el ámbito escolar, gestamos un taller reflexivo alusivo al Día del Respeto a la Diversidad Cultural, utilizando materiales bibliográficos procedentes del ámbito académico y recursos audiovisuales variados y que incluyó una instancia de producción artística. A partir de allí, en la continuidad del proyecto desde la universidad elaboramos una propuesta de actividad abocada al análisis de las representaciones y estereotipos de las sociedades indígenas a través de recursos audiovisuales. Estos elementos actuaron como disparadores y sintetizadores para resignificar cuestiones como la tolerancia, la aceptación de la diversidad y la importancia del legado cultural de los pueblos originarios de América.

Source-sink relations and kernel weight in maize inbred lines and hybrids: Responses to contrasting nitrogen supply levels Hisse, Ignacio Ruben; D'andrea, Karina Elizabeth; Otegui, Maria Elena Maize (Zea mays, L.) kernel weight (KW) is regulated by the source-sink relationship at the early grain-filling period, when potential kernel size is defined, and at the effective grain-filling period, when final KW is established. The relative importance of each period is expected to depend upon the occurrence or not of environmental restrictions to plant growth. The objective of this study was to analyze the effect of nitrogen (N) availability on KW determination in two different groups of genotypes (inbreds and hybrids) when it is caused by changes in the source-sink relationship at mentioned periods. Six inbred lines of different genetic background and their F1 derived hybrids were tested in the field under two contrasting soil N levels (N0: low; N1: high). Almost all evaluated traits had greater mean values (P < 0.001) at N1 than at N0 level, except the plant growth rate per kernel during the critical period for kernel set (PGRCP kernel−1). However, the magnitude of the response to increased N was considerably higher for hybrids than for inbreds. Under contrasting N availability, plant growth during grain filling (PGGF) was the main determinant of increments registered in the source-sink ratio during this stage (i.e. PGGF kernel−1), and KW was chiefly associated with this ratio (r2 ≥ 0.50, P < 0.001). By contrast, the association between KW and PGRCP kernel-1 was important only at N1, and more robust for hybrids (r2 = 0.61, P < 0.001) than for inbreds (r2 = 0.34, P < 0.001). The uncoupling between both source-sink ratios observed at N0, as a result of a decreased post-flowering growth in this treatment, was responsible for differences in KW response to the PGRCP kernel−1 detected between N levels. The KW of inbreds was almost unaffected by mentioned N effects on the analyzed source-sink ratios, a trend attributed to negative inbreeding depression effects on traits controlling seed expansion. These differential responses between genotypic groups should be considered in breeding programs targeting KW increase.

DFT and vibrational spectroscopy study of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid Kausteklis, Jonas; Aleksa, Valdemaras; Iramain, Maximiliano Alberto; Brandan, Silvia Antonia Structural and vibrational characterizations for the 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid ([BMIM][OTF]) were performed combining the experimental Raman spectrum with density functional theory (DFT) calculations based in the hybrid B3LYP/6-311++G** level of theory. Structurally, the trifluoromethanesulfonate anion, [OTF] is linked to 1-butyl-3-methylimidazolium cation, [BMIM] by a bidentate coordination by means of two different S?O??H hydrogen bonds. The [OTF] anion plays a very important role in the structure and stability of [BMIM][OTF], as observed by the strong increase in the dipole moment value when the anion is added to cation. Intramolecular H and halogen bonds evidence the high stability of ionic liquid, as supported by NBO and AIM calculations. Very good correlations were observed between the predicted infrared and Raman spectra with the corresponding experimental ones. The different Mulliken charges observed on the O atoms of O??H bonds support the asymmetric bidentate coordination of [OTF] anion with the [BMIM] cation. The [OTF] anion increase the reactivity of [BMIM][OTF], as compared with [BMIM][NO3]. In addition, the [OTF] anion reduces drastically the electrophilicity and nucleophilicity indexes of cation evidencing the strong influence of anion on the properties of cation. The vibrational analyses have revealed a very important shifting of one of the two antisymmetric modes of [BMIM][OTF] towards lower wavenumbers due probably to an asymmetric of S[dbnd]O⋯H bond interaction which is no observed in the anion. The complete vibrational assignments were performed for ionic liquid, cation and anion and the harmonic scaled force constants were reported at the same level of theory.

Advances on metabolism and disposition of Bbnzimidazoles anthelmintic in Fasciola hepatica: its contribution to the phenomenon of anthelmintic resistance Solana, Hugo Daniel; Scarcella, Silvana Andrea; Solana, María Victoria The fascioliasis is an important zoonotic disease, particularly in underdeveloped countries. In fascioliasis, the anthelmintic control has been done mainly by the use of triclabendazole (TCBZ), which is metabolized into the anti-helmintic metabolite, sulphoxide in the host liver and targeted to the subcellular fractions of the parasite, Fasciola hepatica (Liver Fluke). The existence of genetically different populations of liver fluke could allow, against any selection pressure, natural or artificial (for use fasciolicidesproducts and/or control measures), one or more populations of F. hepatica to be able to survive and create resistance or adaptability to such selective pressure. It is known that the uptake and effects of TCBZ and the sulfoxide metabolite is significantly greater in TCBZ-susceptible isolates in comparison to the TCBZ-resistant flukes. This result are analyzed in the present contribution.

Cytotoxic and genotoxic effects induced by enrofloxacin-based antibiotic formulation Floxagen® in two experimental models of bovine cells in vitro: peripheral lymphocytes and cumulus cells Anchordoquy, Juan Patricio; Anchordoquy, Juan Mateo; Nikoloff, Noelia; Gambaro, Rocío Celeste; Padula, Gisel; Furnus, Cecilia Cristina; Seoane, Analia Isabel The in vitro effect of enrofloxacin (EFZ) was tested on two experimental somatic bovine cells in vitro: peripheral lymphocytes (PLs) and cumulus cells (CCs). The cytotoxicity and genotoxicity of this veterinary antibiotic were assessed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays, single-cell gel electrophoresis (SCGE) assay, and cytokinesis-block micronucleus cytome (CBMN cyt) assay. Cells were treated during 24 h, and three concentrations were tested (50 μg/mL, 100 μg/mL, 150 μg/mL). When EFZ was tested in PLs, the results demonstrated that the antibiotic was able to induce cell death and DNA damage with all concentrations. In addition, 50 μg/mL and 100 μg/mL EFZ increased frequencies of micronuclei (MNi). On the other hand, the highest EFZ concentration occasioned cellular cytotoxicity in CCs as evidenced by mitochondrial activity alterations. Nevertheless, EFZ was not able to induce DNA damage and MNi in CCs. These results represent the first experimental evidence of genotoxic and cytotoxic effects exerted by EFZ in bovine PLs and CCs.

Inhibition of antigen presentation by Brucella: many more than many ways Barrionuevo, Paula; Giambartolomei, Guillermo Hernan Brucella infection activates the immune system and favors the differentiation of CD4+ and CD8+ T cells. To persist during a long time inside macrophages evading immune surveillance of these T cells the pathogen must exploit different evasion strategies. We review the mechanisms whereby Brucella, through TLR signaling, inhibits MHC class I and II antigen presentation, allowing infected macrophages to become effective niches for Brucella survival.

Effects of one-step alkaline and two-step alkaline/dilute acid and alkaline/steam explosion pretreatments on the structure of isolated pine lignin Das, Parthapratim; Stoffel, Romina Bettiana; Area, Maria Cristina; Ragauskas, Arthur J. Biological valorization of biomass most often depends on the efficient reduction of plant cell wall recalcitrance and conversion of lignin – the most recalcitrant constituent – to fuels, chemicals and/or value-added substances. Lignin conversion to fuels and value-added chemicals requires a sound understanding of the structure of lignin before and after different pretreatments. In the current work, an effort has been made to compare the structural differences in isolated pine lignin after one- (alkaline) and two-step (alkaline/dilute acid and alkaline/steam explosion) pretreatments. Our results indicate removal of the low molecular weight fraction of lignin after an initial alkaline pretreatment. A subsequent dilute acid pretreatment resulted in the loss of lignin inter-unit linkages such as β-O-4’ aryl ethers. However, with a steam explosion pretreatment, lignin exhibited a competing condensation process leading to increased condensed lignin structures.

Influence of {111} nanofaceting on the dynamics of CO adsorption and oxidation over Au supported on CeO 2 nanocubes: An operando DRIFT insight Fernández García, Susana; Collins, Sebastián Enrique; Tinoco, Miguel; Hungría, Ana B.; Calvino, José J.; Cauqui, Miguel A.; Chen, Xiaowei CO adsorption and further reaction with O 2 on two Au/CeO 2 model systems have been investigated by operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) in order to unveil the active sites for CO oxidation. One of the ceria supports was constituted by crystallites depicting a nanocube shape bounded mostly by {100} planes, whilst the second one was consisted of nanocubes whose {110} surfaces were reconstructed into {111}-nanofacets with a zig-zag shape. The deconvolution of the CO adsorption bands and a detailed analysis of the time-evolution of these bands were also carried out. These studies evidenced a fast adsorption of CO over Au° and then Au δ- -CO bands appeared during exposure to CO, in parallel with the appearance of Ce 3+ features. Such changes suggest that CO adsorption process starts on Au sites on the low coordinated sites of the surface of the Au nanoparticles and their transfer to the interface sites. By comparing the nanostructure of the two catalysts, the Au δ- -CO species could be fruitfully related to CO adsorption on sites located at the Au||CeO 2 perimeter. The sample containing gold nanoparticles dispersed over the {111}-nanofaceted CeO 2 nanocubes, which retained a higher amount of gold nanoparticles, depicts higher contribution of Au δ− −CO bands than the other Au catalyst in the DRIFT spectra. The dynamic DRIFT study clearly revealed that the CO species adsorbed on Au δ- sites were the most reactive ones in both gold supported systems for CO oxidation. This explains much higher TOF values observed on the catalyst prepared on the surface reconstructed support. A detailed analysis on the reactivity was performed by modulation excitation spectroscopy (MES). The presence of peroxide surface species (O 2 2- ) in nanofaceted {111} could lead to higher catalytic activity than that of gold on the non-reconstructed catalyst.

Recognition of species groups of Naupactus Dejean (Coleoptera: Curculionidae) from Argentina and neighboring countries del Rio, Maria Guadalupe; Lanteri, Analía Alicia Naupactus Dejean is the most diverse genus of the tribe Naupactini (Curculionidae: Entiminae), with more than 200 species occurring in South America, of which about 40 range in Argentina and neighboring countries. The Argentinean species treated herein were classified into nine groups having different biogeographic patterns: (1) the groups of Naupactus xanthographus, N. delicatulus and N. auricinctus mainly occur in northeastern Argentina (Misiones province) and reach the highest species diversity in the Atlantic and Parana forests of Brazil; (2) the groups of N. hirtellus, N. cinereidorsum, N. rivulosus and N. tarsalis show the highest species diversity in the Chacoan biogeographic province and also occur in the Yungas, Espinal, Monte, Parana forest (Argentina) and Cerrado (Brazil); (3) the groups of N. leucoloma and N. purpureoviolaceus have the highest species diversity in the Pampean biogeographic province, being also present in adjoining areas, mainly Chaco, Espinal, Monte and Parana forest. We provide descriptions, a dichotomous key, habitus photographs and line drawings of genitalia for the identification of the nine species groups, and a list of the Argentinean species from each group, together with their abbreviated synonymies, updated geographic distributions (including six new country records and several state/province records) and host plant associations. We discuss the characters that allow the separation of the species groups in a geographic distribution context, and provide information on species reassigned to genera other than Naupactus; among these, we transferred N. cephalotes (Hustache) to the tribe Tanymecini, genus Eurymetopellus, establishing the new combination Eurymetopellus cephalotes.

Role of the Hsp90-immunophilin heterocomplex in cancer disease de Leo, Sonia Alejandra; Zgajnar, Nadia Romina; Mazaira, Gisela Ileana; Erlejman, Alejandra Giselle; Galigniana, Mario Daniel The identification of new factors that may function as cancer markers and becomeeventual pharmacologic targets is a challenge that may influence the management of tumor developmentand management. Recent discoveries connecting Hsp90-binding immunophilins with theregulation of signalling events that can modulate cancer progression transform this family of proteinsin potential unconventional factors that may impact on the screening and diagnosis of malignantdiseases. Immunophilins are molecular chaperones that group a family of intracellular receptorsfor immunosuppressive compounds. A subfamily of the immunophilin family is characterizedby showing structural tetratricopeptide repeats, protein domains that are able to interact with theC-terminal end of the molecular chaperone Hsp90, and via the proper Hsp90-immunophilin complex,the biological properties of a number of client-proteins involved in cancer biology are modulated.Recent discoveries have demonstrated that two of the most studied members of this Hsp90-binding subfamily of immunophilins, FKBP51 and FKBP52, participate in several cellular processessuch as apoptosis, carcinogenesis progression, and chemoresistance. While the expressionlevels of some members of the immunophilin family are affected in both cancer cell lines andhuman cancer tissues compared to normal samples, novel regulatory mechanisms have emergedduring the last few years for several client-factors of immunophilins that are major players in cancerdevelopment and progression, among them steroid receptors, the transctiption factor NF-κBand the catalytic subunit of telomerase, hTERT. In this review, recent findings related to the biologicalproperties of both iconic Hsp90-binding immunophilins, FKBP51 and FKBP52, are reviewedwithin the context of their interactions with those chaperoned client-factors. The potentialroles of both immunophilins as potential cancer biomarkers and non-conventional pharmacologictargets for cancer treatment are discussed.Keywords: Heat-shock proteins; immunophilins; cancer; peptidylprolyl isomerase;

Determination of 2-hydroxy-4-methoxybenzophenone in mice serum and human plasma by ultra-high-performance liquid chromatography enhanced by chemometrics Teglia, Carla Mariela; Santamaría, Clarisa Guillermina; Rodriguez, Horacio Adolfo; Culzoni, Maria Julia; Goicoechea, Hector Casimiro This work presents the development of a strategy for the quantitation of 2-hydroxy-4-methoxybenzophenone (BP-3) in mice serum and human plasma. The instrumental determination only lasts 2 min and is based on ultra-high-performance liquid chromatography (UHPLC) coupled to second-order data modeling with multivariate curve resolution-alternating least-squares (MCR-ALS). Coelution of BP-3 with the matrix components was resolved by exploiting the second-order advantage of multi-way calibration. The validation study led to the following results: linear range from 0.002 to 1.509 μg mL−1; in the case of mice serum samples: recoveries from 95 to 98%, with intra and inter day precision of 2.7 and 5.7, respectively; and in the case of human plasma samples: recoveries from 94 to 99% with intra and inter day precision of 2.3 and 4.6%, respectively. Special emphasis was put on the determination of the LOD and LOQ by utilizing several approaches for their calculation and making focus on the experimental verification of the figures provided by the multivariate methodology. Following the mentioned approach, the LOD and LOQ of the method were estimated as 0.66 and 2.00 ng mL−1, respectively. Eventually, the method was successfully applied to the determination of BP-3 in mice serum.

Enzymatic synthesis of non-natural trisaccharides and galactosides; Insights of their interaction with galectins as a function of their structure Porciúncula González, Cecilia; Cagnoni, Alejandro; Mariño, Karina Valeria; Fontana, Carolina; Saenz Méndez, Patricia; Irazoqui, Gabriela; Giacomini, Cecilia Galectins are a family of carbohydrate-recognizing proteins that by interacting with specific glycoepitopes can mediate important biological processes, including immune cell homeostasis and activation of tolerogenic circuits. Among the different members of this family, Galectin 1 and 3 have shown pro-tumorigenic effects, being overexpressed in numerous neoplasic diseases, proving to be relevant in tumor immune escape, tumor progression and resistance to drug-induced apoptosis. Thus, generation of specific glycosides that could inhibit their pro-tumorigenic ability by blocking their carbohydrate recognition domain is one of the current major challenges in the field. Considering that galectin-ligand binding strength is closely related to the ligand structure, analysis of this relationship provides valuable information for rational design of high-affinity ligands that could work as effective galectin inhibitors. Taking profit of the ability of glycosidases to catalyze transglycosylation reactions we achieved the enzymatic synthesis of β- D -Galp-(1 → 6)-β- D -Galp-(1 → 4)- D -Glcp (2), a mixture of β- D -Galp-(1 → 6)-β- D -Glcp-(1 → 4)- D -Glcp (5) and β- D -Galp-(1 → 3)-β- D -Glcp-(1 → 4)- D -Glcp (6), and finally benzyl β-D -galactopyranoside (9), with reaction yields between 16 and 27%. All the galactosides were purified, and characterized using 1 H and 13 C nuclear magnetic resonance spectroscopy. Docking results performed between the synthesized compounds and human Galectin 1 (hGal-1) and human Galectin 3 (hGal-3) showed that the replacement of a glucose moiety linked to the terminal galactose with a galactose moiety, decreases the affinity for these galectins. Moreover, regarding the interglycosidic bond the most favorable β-Gal linkage seems to be β(1 → 4) followed by β(1 → 3) and β(1 → 6) for hGal-1, and β(1 → 4) followed by β(1 → 6) and β(1 → 3) for hGal-3. These results were in accordance with the IC50 values obtained with in vitro solid phase inhibition assays. Therefore, docking results obtained in this work proved to be a very good approximation for predicting binding affinity of novel galactosides.

The Puesto Piris Formation: Evidence of basin-development in the North Patagonian Massif during crustal extension associated with Gondwana breakup Strazzere, Leonardo; Gregori, Daniel Alfredo; Benedini, Leonardo; Marcos, Paulo; Barros, Mercedes Virginia; Geraldes, Mauro C.; Pavon Pivetta, Cecilia Mariana The Marifil Volcanic Complex, exposed in the eastern North Patagonian Massif, Argentina, includes up to 550 m of red conglomerates, sandstones, black siltstones, limestones, and reworked tuff of the Puesto Piris Formation. The basal part of this unit, which was deposited in high-gradient topographic relief, is composed of conglomerates and sandstones with thin layers of reworked tuffs. The lithofacies associations of the basal part indicate that the depositional mechanisms were mantled and gravitational flows. The middle part of the unit consists of fine sandstones, limestones, and black siltstones that were deposited in low-energy fluvial and lacustrine environments. The outcrops are located along the NE–SW direction and the major thickest units represented by limestones and siltstones, occur near the southeastern border of this NE–SW depocenter. Since the rhyolitic and trachytic lava flows and tuffs of the Marifil Volcanic Complex are interbedded with the sedimentary sequences of the Puesto Piris Formation, both units are coeval. Zircon U–Pb age was obtained for a trachytic lava flow (193.4 ± 3.1 Ma) suggesting that sedimentation and volcanism are Sinemurian. This extensional episode was recorded in the eastern, western, and southwestern sectors of the North Patagonian Massif, and is possibly associated with the Gondwana supercontinent breakup.

Nitrogen balance in a plant-soil system under different cover crop-soybean cropping in Argentina Landriscini, María Rosa; Galantini, Juan Alberto; Duval, Matias Ezequiel; Capurro, Julia E. Cover crops (CC) provide many benefits for the soil and the following crop but their effects on nitrogen (N) release and balance in continuous no-tillage soybean (Glycine max L. Merr.) production are little known. Estimation of the biological nitrogen fixation (BNF) in intensive agricultural systems under soybean is essential to understanding the N dynamics and to determining the balances and crop demands. This study (2006–2011) was performed on a Typic Argiudoll under no-tillage in the province of Santa Fe, Argentina. The aims were to study the effect of fall winter CC, such as wheat (W), oats (O), oats + vetch (O + V) and vetch (V), on the yield and N-content of the following crop (soybean) and to quantify the contribution of the BNF and N-balance. Three methodologies were used for BNF estimation: 1) a linear regression model between BNF and N-uptake by soybean; 2) the natural 15N abundance in soybean and 3) the average BNF in the Pampa region. Gramineous CC developed more dry matter than pure legume species, with intermediate values for the gramineous-legume mixture. Biological fixation provides 60–70% of absorbed N, according to the estimation method. Within the rainfall range of 500–1000 mm during the soybean cycle, CC did not affect the grain yield or soybean dry matter production. The partial N-balance was always positive, with differences between the techniques used for BNF estimation. Cover crops have contributed to the positive soil N-balance. Gramineous CC stored 22% more N-content in the soil surface layer than the others. Cover crops showed 15% higher index of N-stratification on the surface compared to the control soil. Using CC would be an efficient alternative to produce biomass and to supply N to the soil for the subsequent crop.

New remains of Nothrotheriinae (Mammalia, Xenarthra) from Late Pleistocene fluvial deposits of Northern Pampa (Santa Fe Province, Argentina) Vezzosi, Raúl Ignacio; Brandoni, Diego; Brunetto, Ernesto; Zalazar, Maria Cecilia In this contribution the record of a Nothrotheriinae (Xenarthra, Tardigrada) ground sloth is reported from the Late Pleistocene of the Northern Pampa of Santa Fe Province, Argentina. The stratigraphic unit where the fossil was collected corresponds to fluvial-palustrine sediments of the Timbúes Formation, outcropping along the Carcarañá River valley. The relative stratigraphic position of this lithostratigraphic unit, observed in several sections mainly on the Paraná River cliffs near Carcarañá River distal area, suggests that it was deposited during the Last Interglacial Stage. The specimen (MPAHND-135), assigned to Nothrotherium cf. torresi, is represented by the proximal two-thirds of a left femur that shows a prominent lesser trochanter and no connection between the third trochanter and the ectepicondyle. The presence of Nothrotherium cf. torresi in sediments related to humid conditions supports the idea that Nothrotheriinae had great ecological tolerance and was capable of inhabiting climates ranging from cold and arid, as was previously proposed, to warm and humid.