Robust sieve estimators for functional canonical correlation analysis Alvarez, Agustin; Boente Boente, Graciela Lina; Kudraszow, Nadia Laura In this paper, we propose robust estimators for the first canonical correlation and directions of random elements on Hilbert separable spaces by combining sieves and robust association measures, leading to Fisher-consistent estimators for appropriate choices of the association measure. Under regularity conditions, the resulting estimators are consistent. The robust procedure allows us to construct detection rules to identify possible influential observations. The finite sample performance is illustrated through a simulation study in which contaminated data is included. The benefits of considering robust estimators are also illustrated on a real data set where the detection methods reveal the presence of influential observations for the first canonical directions that would be missed otherwise.

A bacterial endophyte from apoplast fluids protects canola plants from different phytopathogens via antibiosis and induction of host resistance Romero, Fernando Matias; Rossi, Franco Rubén; Gárriz, Andrés; Carrasco, Pedro; Ruiz, Oscar Adolfo Endophytic bacteria colonize inner plant tissues and thrive at the apoplast, which is considered its main reservoir. Because this niche is the place where the main molecular events take place between beneficial and pathogenic microorganisms, the aim of this work was to characterize culturable endophytic bacteria from apoplastic fluids obtained from field-grown canola leaves and analyze their potential for biological control of diseases caused by Xanthomonas campestris, Sclerotinia sclerotiorum, and Leptosphaeria maculans. Dual-culture analysis indicated that three isolates (Apo8, Apo11, and Apo12) were able to inhibit the growth of all three phytopathogens. Sequencing of the 16S ribosomal RNA and rpoD genes of these isolates revealed that they are closely related to Pseudomonas viridiflava. One of the isolates, Apo11, was able to diminish the propagation of X. campestris in whole-plant assays. At the same time, Apo11 inoculation reduced the necrotic lesions provoked by S. sclerotiorum on canola leaves. This protective effect might be due to the induction of resistance in the host mediated by salicylic and jasmonic acid signaling pathways or the production of compounds with antimicrobial activity. At the same time, Apo11 inoculation promoted canola plant growth. Thus, the isolate characterized in this work has several desirable characteristics, which make it a potential candidate for the formulation of biotechnological products to control plant diseases or promote plant growth.

Root phenotypes of dwarf and “overgrowth” SLN1 barley mutants, and implications for hypoxic stress tolerance Moriconi, Jorge Ignacio; Kotula, Lukasz; Santa Maria, Guillermo Esteban; Colmer, Timothy David Gibberellins are central to the regulation of plant development and growth. Action of gibberellins involves the degradation of DELLA proteins, which are negative regulators of growth. In barley (Hordeum vulgare), certain mutations affecting genes involved in gibberellin synthesis or coding for the barley DELLA protein (Sln1) confer dwarfism. Recent studies have identified new alleles of Sln1 with the capacity to revert the dwarf phenotype back to the taller phenotypes. While the effect of these overgrowth alleles on shoot phenotypes has been explored, no information is available for roots. Here, we examined aspects of the root phenotypes displayed by plants with various Sln1 gene alleles, and tested responses to growth in an O 2 -deficient root-zone as occurs during soil waterlogging. One overgrowth line, bearing the Sln1d.8 allele carrying two amino acid substitutions (one in the amino terminus and one in the GRAS domain of the encoded DELLA protein), displays profound and opposite effects on shoot height and root length. While it stimulates shoot height, it severely compromises root length by a reduction of cell size in zones distal to the root apex. In addition, Sln1d.8 plants counteract the negative effect of the original mutation on the formation of adventitious roots. Interestingly, plants bearing this allele display enhanced resistance to flooding stress in a way non-related with increased root porosity. Thus, various Sln1 gene alleles contribute to root phenotypes and can also influence plant responses to root-zone O 2 -deficiency stress.

El Pleistoceno de la provincia de Buenos Aires y sus mamíferos; The Pleistocene of the Buenos Aires Province and their mammals Soibelzon, Esteban; Soibelzon, Leopoldo Héctor; Gasparini, Germán Mariano; Tonni, Eduardo Pedro En el actual territorio de la provincia de Buenos Aires se encuentran secuencias sedimentarias con abundante contenido fósil, que constituyen la base de la escala cronológica sudamericana para el Neógeno y Cuaternario. Desde la segunda mitad del siglo XIX y especialmente a partir del aporte de Florentino Ameghino, comenzó a desarrollarse un esquema estratigráfico con base en el contenido paleontológico. Los sedimentos portadores fueron denominados de diferentes maneras: “pampean formation”, “limo pampa”, “terreno pampa”, o “formación pampeana”, entre otras. Es Ameghino quien divide y denomina “pisos” u “horizontes” pampeanos (ej. “piso pampeano lacustre o lujanense”, “piso pampeano medio o belgranense”). Estos nombres posteriormente se utilizaron como base de las secuencias de “Edades Mamífero” y, más recientemente y de acuerdo al Código Argentino de Estratigrafía, para designar Pisos/Edades. Así, el Pleistoceno incluye el Subpiso Sanandresense (del Piso Marplatense) y los Pisos Ensenadense, Bonaerense y Lujanense, portadores de una mastofauna que caracteriza y define a las biozonas que los sustentan (Ctenomys chapalmalensis, Mesotherium cristatum, Megatherium americanum, Equus (Amerhippus) neogaeus). A través de este esquema, se pueden establecer adecuadas relaciones de superposición, de primeros y últimos registros, así como de abundancia de fósiles y establecer cronologías acertadas para procesos tales como el Gran Intercambio Biótico Americano. Asimismo, se registran numerosos eventos glaciales e interglaciales que provocaron desplazamientos de la fauna. Varios de los perfiles tipo o localidades clásicas estudiadas durante más de 150 años han desaparecido (como “toscas del Río de La Plata”, Punta Hermengo o el puerto de La Plata en Ensenada) en virtud de la actividad humana.; Buenos Aires province contains sedimentary sequences with abundant fossil records, which constitute the basis of the chronological scale of South America for the Neogene and Quaternary. Since the second half of the nineteenth century and especially from the contribution of Florentino Ameghino, a stratigraphic scheme began to be developed based on the paleontological content. The outcropping sediments were named in different ways e.g. “Pampean formation”, “limo pampa”, “terra pampa”, or “pampean formation”, among others. Ameghino divided and named them as “stages” or “horizon” (e.g. “piso pampeano lacustre o lujanense”, “piso pampeano medio o belgranense”). These names were subsequently used for sequences of “Land Mammals Ages”; more recently and according to the Argentine Code of Stratigraphy, were used to designate Stages/Ages. Thus, the Pleistocene includes the Sanandresian Substage (from Marplatan Stage) and the Ensenadan, Bonaerian and Lujanian Stages, containing mammals that characterizes and defines the biozones that support them (Ctenomys chapalmalensis, Mesotherium cristatum, Megatherium americanum, Equus (Amerhippus) neogaeus). Through this scheme, suitable relationships of superposition, first and last records, as well as abundance of fossils can be recognized. Besides that, certain chronologies can be established for processes such as the Great American Biotic Interchange. Also, numerous glacial and interglacial events that caused displacement of fauna are registered. Several type profiles or classic paleontological localities studied during more than 150 years have disappeared (e.g. “toscas del Río de La Plata”, Punta Hermengo or the harbor of La Plata in Ensenada) as a result of human activity.

PET-adapted therapy after three cycles of ABVD for all stages of Hodgkin lymphoma: results of the GATLA LH-05 trial Pavlovsky, Astrid; Fernández, Isolda; Kurgansky, Nicolas; Prates, Virginia; Zoppegno, Lucia; Negri, Pedro; Milone, Gustavo; Cerutti, Ider; Zabaljauregui, Soledad; Mariano, Romina; Grecco, Horacio F.; Basquiera, Ana Lisa; Saba, Silvia; Rudoy, Silvia; Sackmann, Federico; Castano, Vanesa; Remaggi, Guillermina; Cabrejo, María del Rosario; Roveri, Eriberto; Casale, María Florencia; Cabane, Vanina; Taus, Rossana; Venturini, Claudia; Sakamoto, Francisco; Varela, Ana I.; Riddick, Maximiliano Luis; Pavlovsky, Santiago The role of Ann Arbor staging in determining treatment intensity after achieving a negative positron emission tomography (PET) has not been established in classical Hodgkin lymphoma (cHL). Patients with stage I–IV cHL, received three cycles of ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) and an interim PET scan (PET3). PET3-negative patients received no further therapy. PET3-positive patients received three additional cycles of ABVD plus involved-field radiation therapy or salvage chemotherapy, if refractory to ABVD, and were re-evaluated by PET scan (PET6). Study endpoints were 3-year progression-free survival (PFS) and overall survival (OS) rates. Two hundred and thirty-nine patients with early-stage and 138 with advanced-stage were evaluable. Overall, 260 patients (70%) were PET3-negative and had higher 3-year PFS (90% vs. 65%; P < 0 0001) and OS (98% vs. 92%; P = 0 007) rates than PET3-positive patients. All PET3-negative patients, regardless of disease stage at diagnosis, achieved similarly good PFS (90–91%; P = 0 76) and OS (97–99%). The only independent prognostic factor for PFS was PET3-negativity (Hazard ratio 3 8; 95% confidence interval 2 4–6 3; P < 0 0001). This study suggests that cHL patients who achieve a negative PET3 following ABVD have an excellent outcome, regardless of stage at diagnosis. An appropriately powered, phase III trial will be necessary to confirm these findings.

Deformed Weitzenböck Connections and Double Field Theory Penas, Victor Alejandro We revisit the generalized connection of Double Field Theory. We implement a procedure that allow us to re-write the Double Field Theory equations of motion in terms of geometric quantities (like generalized torsion and non-metricity tensors) based on other connections rather than the usual generalized Levi-Civita connection and the generalized Riemann curvature. We define a generalized contorsion tensor and obtain, as a particular case, the Teleparallel equivalent of Double Field Theory. To do this, we first need to revisit generic connections in standard geometry written in terms of first-order derivatives of the vielbein in order to obtain equivalent theories to Einstein Gravity (like for instance the Teleparallel gravity case). The results are then easily extrapolated to DFT.

Heat transfer enhancement in panel type radiators using delta-wing vortex generators Garelli, Luciano; Rios Rodriguez, Gustavo Adolfo; Dorella, Jonathan Jesus; Storti, Mario Alberto In this paper, a three-dimensional numerical simulation is used to analyze the performance of delta-wing vortex generators for enhancing the heat exchange in panel type radiators, which are widely used in electric power transformers. The study is focused on natural convection and buoyancy-driven flows, which are common working conditions for this type of heat exchanger. First, the performance of a single delta wing between parallel vertical plates is analyzed to establish the best combination of characteristic parameters to obtain the highest thermal enhancement factor. It is found that separating the vortex generator from the surface of the panel has positive effects in this sense. Then, with the selected configuration, a set of delta-wing arrays is placed on the surface of the heat exchanger, and the resulting thermo-fluid dynamic is analyzed. The total heat flux and local/global heat exchange coefficients are reported. Using these passive devices, the overall heat transfer improves by 12%.

Bacterial nano cellullose as non-active pharmaceutical ingredient production optimization, quality control development and prototype design González, Exequiel Elías; Cerúsico, Nicolás Abel; Moreno, María Julieta; Sesto Cabral, María Eugenia Materials from bio-based resources have attracted immense research interest in recent years as a result of their very high potentials for fabricating several high-value products with low impact on the environment. Cellulose produced by some bacteria has received great attention. Bacterial Nano Cellulose (BNC) imparts attractive combinations of biophysicochemical characteristics and improved mechanical properties. The aims of this work was to develop growth media for increase BNC production, characterize a non-active pharmaceutical ingredient (NAPI), design an efficient quality control method by FTIR and SEM by compared that NAPI with commercial ones and present a first prototype of a pharmaceutical product. LB and KB media were modified and BNC obtained had better quality respect its crystallinity and/or polymerization degree than the BNC from commercial media. Different extraction processes were proposed, in no case microbiological material remnants has been found. Films for controlled drugs release prototype were made and its physical properties such as water solubility, moisture content, swelling property, UV barrier capacity were evaluated. BNC films present an additional advantage, having lower UV permeability than films with cellulose of vegetal origin, adding potentialities to a patch design that protects the tissue and the Active Pharmaceutical Ingredients.

Plasticity in root symbioses following shifts in soil nutrient availability during long-term ecosystem development Teste, Francois; Laliberté, Etienne The vast majority of terrestrial plants form root symbioses with arbuscular mycorrhizal (AM) fungi to enhance nutrient (particularly phosphorus, P) acquisition. However, some plant species also form dual symbioses involving ectomycorrhizal (ECM) fungi, with a subset of those also forming triple symbioses also involving dinitrogen (N 2 )-fixing bacteria. It has been suggested that these plants show plasticity in root symbioses to optimise nutrient acquisition depending on the type and strength of soil nutrient limitation (e.g., N vs. P), yet empirical evidence remains limited. Alternatively, the degree of investment or “preference” in particular root symbioses might simply reflect differences in inoculum potential among soils of contrasting nutrient availability, reflecting adaptations of root symbionts to different edaphic conditions. Here, we grew two co-occurring plant species forming triple (AM/ECM/N 2 -fixing; Acacia rostellifera) or dual (AM/ECM; Melaleuca systena) symbioses in soils of increasing age and contrasting nutrient availability from an Australian long-term soil chronosequence to disentangle the relative importance of abiotic factors (e.g., soil nutrient availability and stoichiometry) and biotic factors (e.g., soil inoculum potential) in determining root colonisation patterns and functional outcomes of these multiple root symbioses. For both plant species, we found clear hump-shaped plant growth patterns along the pedogenesis-driven gradient in soil nutrient availability, with peak growth in intermediate-aged soils, while high levels of mycorrhizal colonisation by the “preferred” root symbionts were maintained across all soils. We found large increases (540%) in foliar manganese concentrations with increasing soil age and declining P availability, suggesting that plants may be relying on the release of carboxylates to help acquire P in the most P-impoverished soils. Finally, we found that soil abiotic properties, such as strong differences in soil nutrient availability, are generally more important than soil inoculum potential in explaining these shifts in our plant and root responses. Synthesis. Our study suggests that plants capable of forming multiple root symbioses show plasticity in their nutrient-acquisition strategies following shifts in soil nutrients during long-term ecosystem development, yet maintain a preference for certain root symbionts despite changes in soil microbial inoculum.

Familias capitulares y poder político en el Cabildo de Buenos Aires, 1776-1810; Capitular Families and Political Power in the Cabildo of Buenos Aires, 1776-1810 del Valle, Laura Cristina; Larrosa, Juan Manuel Ceferino Este trabajo analiza la relación existente entre las nominaciones que se hicieron para acceder a cargos en el cabildo de Buenos Aires, entre 1776 y 1810 y la posición relativa de las familias concejiles en la red social capitular. Encontramos evidencia estadística que corrobora ese vínculo entre el poder político y el lugar que ocupan las familias capitulares en la red utilizando análisis de redes sociales. De este modo, podemos localizar las más influyentes y su probabilidad de acceso a los cargos más destacados.; This article analyzes the relationship between the nominations made for seats in the Cabildo of Buenos Aires between 1776 and 1810, and the relative position of political families in the capitular socialnetwork. We found statistical evidence that corroborates the relationship between political power and theposition of capitular families using social network analysis.

12α-hydroxy- N -demethyl-sauroxine, a lycodane type alkaloid from Phlegmariurus saururus Vallejo, Mariana Guadalupe; Corzo, Marcos E.; Ortega, María Gabriela; Agnese, Alicia Mariel 12α-hydroxy-N-demethyl-sauroxine (1), another new Lycopodium alkaloid from the Lycodane group, was isolated from Phlegmariurus saururus (Lam.) B. Øllg. (Lycopodiaceae). Elucidation of the chemical structure and relative stereochemistry were stated by spectroscopic data and chemical correlation. In addition, the inhibitory activity on acetylcholinesterase for 1 was determined as well as for N-methyllycodine (2), a derivative with the same nucleus, previously identified in P. saururus (IC50 = 33.8 ± 0.8 μM and 547.5 ± 0.5 μM, respectively) and N-demethylsauroxine (3) whose inhibition in the actual conditions was better than the previously informed.

Distribución espacial y temporal de las recompensas florales dentro de los capítulos: El caso de Hyalis argentea (Asteraceae); Spatial and temporal distribution of floral rewards within the capitula: The case of Hyalis argentea (Asteraceae) Camina, Julia Laura; Tourn, Elian; Andrada, Ana C.; Pellegrini, Cecilia Noemí; Ashworth, Lorena Una asignación diferencial de recursos entre la función de atracción, recompensa y sexual ha sido observada en capítulos de especies derivadas de Asteraceae. Los capítulos heterógamos están compuestos por flores pistiladas, estaminadas o estériles y perfectas, con lo cual las funciones sexual y de recompensa son realizadas por diferentes tipos de flores y en distintos momentos. Esta distribución espacial y temporal de las recompensas dentro del capítulo no es tan clara en especies con capítulos homógamos, donde todas las flores son perfectas y producen polen y néctar. Aquí evaluamos la distribución espacial y temporal de las recompensas florales en los capítulos homógamos de Hyalis argentea. Comparamos la fenología floral, el número de granos de polen y la concentración y volumen de néctar entre las flores marginales y centrales, y registramos el comportamiento de forrajeo de los visitantes florales. Los capítulos tienen un patrón de floración centrípeto y también alterno y son visitados por abejas, hormigas, mariposas, polillas, escarabajos y trips, siendo Apis mellifera su principal polinizador. No encontramos un patrón temporal en la oferta de recompensas dentro de los capítulos, pero sí un patrón espacial en el volumen de néctar que aumenta desde las flores marginales hacia las del centro del capítulo.Conclusiones: Dicha variabilidad espacial en la cantidad de néctar podría afectar el comportamiento de forrajeo de los polinizadores y así aumentar las probabilidades de polinización cruzada, mejorando la reproducción sexual de esta especie autoincompatible.; Differential resource allocation to attraction, reward, andsexual functions has been observed at capitula level of derived species of Asteraceae. Heterogamous capitula contain a combination of pistillate, staminate or sterileand perfect florets, thus rewarding and sexual functions are performed by different kinds of florets and at different times. Such spatial and temporal distribution of rewards within the capitula is not as clearly established in species with homogamous capitula, where all florets are perfect and produce pollen and nectar. We evaluated the spatial and temporal distribution of floral rewards in homogamous capitula of Hyalis argentea.

¿Es posible el uso sostenible del bosque en Misiones? .Necesidades de manejo a diferentes escalas, investigación, intervenciones de alto impacto, y más recursos económicos; Is sustainable forest harvesting possible in Misiones? The need for multi-scale management, research, high-impact interventions, and funding Campanello, Paula Inés; Von Below, Jonathan; Hilgert, Norma Ines; Cockle, Kristina Louise; Villagra, Mariana; Di Francescantonio, Débora; García, Daily Sofía; Jaramillo, Manuel; Gauto, Oscar Arturo; Goldstein, Guillermo Hernan Para conservar una superficie representativa de los bosques subtropicales de Misiones (Argentina), ecosistema amenazado a nivel mundial, es necesario encontrar una solución económicamente viable a las superficies que actualmente y de acuerdo a la ley 26331 pueden destinarse exclusivamente al manejo sostenible del bosque nativo, así como disminuir la deforestación en las áreas pasibles de ser reemplazadas (901617 ha y 477858 ha, respectivamente, de acuerdo al último ordenamiento territorial llevado a cabo por la Provincia de Misiones). La deforestación, que ocurre desde mediados del siglo pasado, ha sido fomentada por políticas públicas de incentivos a actividades de producción intensivas como las plantaciones forestales u otros cultivos. Los bosques remanentes se encuentran degradados por la explotación de las principales especies nativas comerciales en ciclos de corta menores a 20 años, y la productividad maderera es más baja de lo necesario para sostener económicamente la actividad. La productividad podría recuperarse en algunos casos con manejos post-extracción (por ejemplo, el corte de bambúes y lianas), mientras que en situaciones de mayor degradación se necesitan acciones de manejo más intensivas como la escarificación de los suelos o la plantación de renovales de especies de alto valor comercial y rápido crecimiento que permitan turnos de corta de 30 años e incrementos de al menos 3 m3 ha-1 año-1. Asimismo, se necesita una política de control del comercio ilegal de madera nativa, la cual disminuye los precios y reduce la rentabilidad de productores responsables. Por otra parte, la obtención de madera debería complementarse con disminuciones impositivas, por ejemplo, a través de la compensación por provisión de servicios ecosistémicos, o mediante otros tipos de usos como el aprovechamiento de recursos no madereros. En el caso de pequeños y medianos productores, el gobierno y organizaciones no gubernamentales deberían estimular la conservación del bosque por el uso de sus recursos y servicios ambientales, incentivar activamente la diversificación de la producción, y brindar las herramientas que les permitan a los productores independizarse del cultivo intensivo de tabaco. Es necesario mayor financiamiento directo a los productores para el manejo, así como a organismos dedicados a generar conocimiento que permita avances concretos en el manejo sostenible del bosque.; To conserve a representative area of the subtropical forests of Misiones, a globally endangered ecosystem, it is necessary to find a viable economic solution for the areas destined under Law 26331 exclusively for sustainable management of native forest, and to reduce deforestation in the areas where replacement of native forest is permi�ed (901617 ha and 477858 ha, respectively, according to the latest land use planning by the Province of Misiones). Since the middle of the last century, public policies have provided incentives for plantations of trees and other crops, promoting deforestation. Remnant forests are degraded from exploitation of the principal commercial species in cu�ing cycles shorter than 20 years, and productivity of wood is now too low to be economically useful. Productivity can be improved through post-harvest management (e.g., cu�ing of bamboo and lianas), but on highly degraded sites more intensive management is needed, such as scarifying of soils or planting seedlings of high-value, fast-growing species to allow cu�ing cycles of around 30 years and increments greater than 3 m3 .ha-1.year-1. Action is also needed to control illegal trade in native wood, which diminishes the prices and reduces the viability of socially and environmentally responsible enterprises. Moreover, sustainable management of the native forest should be accompanied by reductions in taxes, for example through payment for ecosystem services, or by other types of use, such as harvesting of non-timber forest products. In the case of small and medium property owners, governments and organizations should stimulate conservation of forest through forest resources and services use, actively encourage diversification of production, and offer tools that promote independence from intensive tobacco cultivation. Funding is needed both directly to producers (through laws) and to institutions that generate knowledge that permits concrete advances in sustainable forest management.

Strategic tourism management to address natural hazards in coastal areas: lessons from Buenos Aires, Argentina Tanana, Ariadna Belén; Rodriguez, Cecilia Alejandra; Gil, Veronica The integral approach to risk is currently an important background for the local development processes within the sustaintability framework. Given the greater frequency and intensity of extreme climatic events in the period 2005-2015, whose inventory shows a total of 78 extreme climate events in the four thermal stations, the purpose of this paper is to analyze risk situations and their corresponding management in the tourist destinations (TD) of the Atlantic coast of Buenos Aires, Argentina. Risk management in TDs has not been addressed in depth in the study area. Because of that, this study is exploratory and descriptive, and it was conducted by quantitative and qualitative methods. The occurrence of extreme weather events was the trigger of this study. Thereafter, the existence of risk situations was analyzed from the combination of natural hazards and material and human damage. The actions taken by the public sector were identified to make a diagnosis of the current management of coastal destinations in the province of Buenos Aires. The result of this study shows that TDs do not apply integral models of risk management, as only 16% of the total registered events were attended by public management from reactive measures to the event. It is believed possible to replicate this study in other TDs, regardless of its main tourism modality, as the analysis carried out in the coastal destinations of Buenos Aires shows that it is necessary to plan and manage risk to avoid and/or mitigate material, social and economic damages of the resident and tourist population. The main implication of the study, in practical terms, is associated with the incorporation of specific equipment for the detection of storms and other meteorological phenomena. In addition, it should start, from the management, with a process of awareness of the resident and tourist population about the risk and its consequences. Knowing the existence of natural hazards is a strategic resource for public management. From the identification of the hazards, exposure and vulnerability of the population, it is possible to begin to take measures to mitigate the risk and conduct awareness campaigns about the risk situations that may arise from the occurrence of meteorological phenomena. in beach areas. In this sense, the development of a culture of risk is very important. The relationship between the occurrence of extreme weather events and tourism has not been addressed in depth in Argentina. Therefore, this work provides an interdisciplinary vision (from tourism and physical geography) about the hazards that extreme phenomena represent in TDs, the situations of risk that they detaches there and the weakness of public management in coastal destinations of Buenos Aires. This case study shows that the absence of planning and risk management has serious implications for the continuity of the development processes of the destinations.

Soluble phenolics extracted from Larrea divaricata leaves modulate soil microbial activity and perennial grass establishment in arid ecosystems of the Patagonian Monte, Argentina Segesso, L.; Carrera, Analía Lorena; Bertiller, Monica Beatriz; Saravi Cisneros, Hebe Sheep grazing induces the reduction of perennial grass cover and the increase of shrub cover with high  concentration of chemical defences. We analysed the effects of secondary metabolites released from green and senesced leaves of the shrub Larrea divaricata on soil microbial activity and the establishment of perennial grasses in arid ecosystems of the Patagonian Monte. We carried out microcosm experiments with soil from plant patches without and with L. divaricata and inert substrate seeded with the perennial grasses Poa ligularis and Nassella tenuis, which are characteristic of the Patagonian Monte. Microcosms were subjected to three watering treatments: distilled water and aqueous extracts of green and senesced leaves of L. divaricata with high concentration of soluble phenolics. We assessed the microbial N-flush and net-N mineralization in soil, andseed germination, survival, and biomass of both perennial grass species. Aqueous leaf extracts led toa 29% increase in microbial N-flush and a 20% reduction in the net-N mineralization. Seed germination was less negatively affected by aqueous leaf extracts in P. ligularis (18% reduction) than in N. tenuis (2?69% reduction). Survival of P. ligularis was not affected by aqueous leaf extracts while that of N. tenuis was 21?45% reduced only in the soil from plant patches without L. divaricata. Biomass accumulation of both perennial grass species was negatively affected by aqueous extracts of senesced leaves. We concluded that soluble metabolites extracted from L. divaricata may have positive or negative effects on microbial activity and potential allelopathic effects on perennial grass regeneration depending on species.

Aceptabilidad sensorial de galletitas recubiertas con un baño de repostería con leche amargo reducido en grasas Carboni, Angela Daniela; Peralta, Juan Manuel; Meza, Barbara Erica del Valle El objetivo del presente trabajo fue valorar el nivel de aceptación sensorial de galletitas recubiertas con un baño de repostería con leche amargo reducido en grasas. El mismo fue elaborado con cacao amargo desgrasado, leche descremada, azúcar impalpable, proteína del lactosuero como sustituto de grasa, glicerina y agua potable. Además, se elaboró un baño de repostería tradicional (usado como control) utilizando los mismos ingredientes pero reemplazando el contenido de sustituto de grasa por aceite de girasol y lecitina de soja. En ambos casos, la composición se adecuó para que cumpla con el Código Alimentario Argentino. Se usaron galletitas dulces comerciales con forma rectangular. Las mismas fueron recubiertas con los baños de repostería usando la técnica de recubrimiento por inmersión (dipping) y luego fueron colocadas en recipientes herméticos, almacenándolas en heladera durante 24 h. El ensayo de aceptabilidad sensorial fue realizado en una sala acondicionada, utilizando un panel de consumidores no entrenados compuesto por 105 participantes. Cada consumidor debió indicar en una planilla el nivel de aceptación por cada muestra y su preferencia. Los valores obtenidos fueron analizados estadísticamente. De acuerdo a los resultados, tanto las galletitas recubiertas con el baño de repostería reducido en grasa como con el tradicional presentaron una alta aceptabilidad. No se encontraron diferencias estadísticamente significativas entre los niveles de aceptación y de preferencia entre ambas muestras por parte de los consumidores. De esta forma, podría considerarse viable la utilización de un baño de repostería con leche amargo reducido en grasa en reemplazo del producto tradicional (elaborado con aceite vegetal) para recubrir galletitas dulces. Se obtendría un producto recubierto con menor contenido calórico, sin modificar la aceptación y la preferencia por el mismo.

Electrooxidation of ethanol and glycerol on carbon supported PtCu nanoparticles Castagna, Rodrigo Martín; Sieben, Juan Manuel; Alvarez, Andrea Elizabeth; Duarte, Marta María Elena Four carbon supported PtCu nanostructured catalysts with Pt:Cu atomic ratios of 1:3.20, 1:2.23, 1:0.61 and 1:0.35 were synthesized by a two-step route, involving the chemical reduction of Cu ions on the carbon support, followed by the partial galvanic replacement of Cu atoms by Pt. Bimetallic nanostructured particles with average sizes in the range of 2.3–3.2 nm were obtained. The bimetallic catalysts with surface Pt contents between 20 and 55 at. % were formed by a Cu-rich core surrounded by a Pt-Cu shell, while that with the highest Pt content presented a uniform alloy structure instead of a core-shell arrangement. The electrocatalytic performance of the as-prepared materials toward ethanol electrooxidation in acid and alkaline media and glycerol oxidation in alkaline environment was investigated by cyclic voltammetry and chronoamperometry. It was observed that the electrocatalytic activity of PtCu nanoparticles was found to depend on the surface composition, platinum utilization efficiency, structure and Pt ensemble. Among the as-prepared catalysts, Pt0·62Cu0·38/C core-shell material showed the best performance for ethanol oxidation in both acid and alkaline environments, while Pt0·24Cu0·76/C and Pt0·31Cu0·69/C core-shell catalysts exhibited the highest activity for glycerol oxidation in alkaline medium. The electrochemical results showed that the catalytic activity of the bimetallic Cu@PtCu core-shell nanostructured nanoparticles is between four and ten times higher than that of a commercial Pt0·51Ru0·49/C catalyst.

Emojis frecuentes en las interacciones por WhatsApp: estudio comparativo entre dos variedades de español (Argentina y España); Frequent emojis in WhatsApp interactions: a comparative study between two Spanish varieties (Argentina and Spain) Cantamutto, Lucía Marina; Vela Delfa, Cristina Dentro de los recursos semióticos disponibles en los sistemas de mensajería instantánea, los emojis son especialmente apreciados por los usuarios gracias al variado repertorio que ofrecen como por su capacidad para dinamizar la interacción. Ante el crecimiento de su uso, nos planteamos la necesidad de disponer de una técnica metodológica que permita no solo identificar los emojis más frecuentes (es decir, los que tengan un uso más extendido en una comunidad de habla), sino también sus principales funciones e interpretaciones más usuales. Por ello, en este trabajo presentamos, por un lado, una metodología que hace posible recuperar los emojis utilizados con mayor frecuencia por parte de un grupo de usuarios de WhatsApp y, por otro, un modelo de exploración e interpretación de estos primeros datos obtenidos. Nuestro diseño metodológico se aplica a la recogida de una muestra comparativa de dos variedades del español: español de España y español de Argentina.; Within the semiotic resources available in instant messaging systems, emojis are especially appreciated by users due to the varied repertoire that offer as for its ability to dynamize the interaction. With the growth of its use, we consider the need for a methodology technique that allows not only to identify the most frequent emojis (i.e., those who have a more extended use in a speech community), but also its main functions and common interpretations. Therefore, in this work, we present, on the one hand, a methodology that makes it possible to recover the emojis used most frequently by a group of WhatsApp users and, on the other, an exploration and interpretation of these first data obtained. We applied our methodological design for the collection of a comparative sample of two Spanish varieties: Spanish of Spain and Spanish of Argentina.

Comments on Digital Current Control in a Rotating Reference Frame-Part I: System Modeling and the Discrete Time-Domain Current Controller With Improved Decoupling Capabilities Busada, Claudio Alberto; Gómez Jorge, Sebastián; Solsona, Jorge Alberto A recent paper by Hoffmann et al. presents a discrete-time model in a rotating dq reference frame of an R-L filter and its current control. The purpose of this note is, first, to show that the discrete model presented in the paper behaves differently to the sampled continuous-time model of the plant, formulated in the stationary αβ reference frame; second, to find the proper discretization of the plant in dq coordinates; and third, to verify that there is cross coupling between axes d and q in the closed-loop system if the original model is used, and that this coupling is not present when using the model found in this note. In the note, it is verified that having a precise model of the plant allows us to fulfill the control objective of obtaining the complete decoupling between axes.

Amide Bond Formation Catalyzed by Recyclable Copper Nanoparticles Supported on Zeolite Y under Mild Conditions Moglie, Yanina Fernanda; Buxaderas, Eduardo; Mancini Gonzalez, Agustina Eliana; Alonso, Francisco; Radivoy, Gabriel Eduardo A series of catalysts based on supported copper nanoparticles have been prepared and tested in the amide bond formation from tertiary amines and acid anhydrides, in the presence of tert-butyl hydroperoxide as an oxidant. Copper nanoparticles on zeolite Y (CuNPs/ZY) was found to be the most efficient catalyst for the synthesis of amides, working in acetonitrile as solvent, under ligand- and base-free conditions in air. The products were obtained in good to excellent yields and in short reaction times. The CuNPs/ZY system also exhibited higher catalytic activity than some commercially available copper and iron sources and it was reused in ten reaction cycles without any further pre-treatment. This methodology has been successfully scaled-up to a gram scale with no detriment to the yield.