Biological traits and growth patterns of pejerrey Odontesthes argentinensis Llompart, Facundo Manuel; Colautti, Dario César; Maiztegui, Tomás; Cruz Jiménez, Adriana Milena; Baigún, Claudio Rafael M. This study assesses for the first time the relationship between annual cycles of different biological indices with growth patterns of a marine pejerrey Odontesthes argentinensis population near its southern-distribution boundary in North Patagonia. The reproductive period is between September and November evidenced by an increase in the gonado-somatic index with a peak in October corresponding to spawning. The reproductive cycle was also coupled with metabolic processes related to energy allocation as shown by changes in the hepato-somatic index and body condition. Total length (LT) at maturity was 270 for females and 282 mm for males, whereas fecundity was estimated at mean ± s.d. = 9380 ± 1797 mature oocytes. Based on the marginal increment analysis, most of the scales showed a maximum value during summer, with a sharp decline thereafter during autumn and winter, indicating that scale rings are formed during the latter period and only once a year. Growth fitted by the von Bertalanffy model for both males and females did not show significant differences and showed a rapid growth during the first 2 years. The shorter reproductive period compared with that of the northern O. argentinensis populations inhabiting tropical and subtropical areas was interpreted as an adjustment to temperate environmental conditions. The larger maximum LT and LT at first maturity are in agreement with the counter-gradient hypothesis and could be related to the selective effects of low temperature and a shorter growing season. This latitude dependency argues strongly against the application of the same fishing regulations for different O. argentinensis populations as a whole and reinforces the need to assess basic biological features at a population scale to promote local sustainable fisheries management.

The Chacoan peccary, Catagonus wagneri (Mammalia, Tayassuidae), in the late Pleistocene (northern Uruguay, South America): paleoecological and paleobiogeographic considerations Gasparini, Germán Mariano; Ubilla, Martin; Tonni, Eduardo Pedro Catagonus wagneri has the most restricted geographical distribution among extant Tayassuidae and inhabited semi-arid thorny forests of dry Chaco in Paraguay, Bolivia and Argentina. Until now, C. wagneri has only been recorded in archaeological, pre-Hispanic deposits from the Santiago del Estero Province, Argentina. A new partially complete skull from the Sopas Formation (Late Pleistocene; Uruguay) is identified as C. wagneri. This is the only fossil record of the species which extends its biochron until the late Pleistocene, and the first one substantially far from its current range; the first fossil record of the species in Uruguay; the most complete fossil material of the species; and it provides relevant ecological and climatic information. According to the ecological and climatic available information of C. wagneri, the presence of this mammal in the late Pleistocene of northern Uruguay indicates a warm climate and arid to semi-arid environments. Even though not associated with the fossil remains of C. wagneri, some mammals included in the sedimentary levels of the Sopas Formation also suggest arid to semi-arid environments. Climatic changes, in particular in the late Pleistocene and Holocene, could be invoked to explain modifications of its geographic range.

Cryptic homoeology analysis in species and hybrids of genus Zea Molina, María del Carmen; López, C. G.; Staltari, Silvana Andrea; Chorzempa, Silvia Elena; Moreno Ferrero, V. Cryptic intergenomic pairing of genus Zea was induced by the use of a diluted colchicine solution in order to elucidate the phylogenetic relations and differentiation of the homoeologous genomes. Results indicate that in species and hybrids with 2n = 20, there was chromosome pairing between the homoeologous A and B genomes with a maximum of 5IV, with the exception of Zea diploperennis and their interspecific hybrids where cryptic homoeologous chromosome pairing was not induced. In almost all 2n = 30 hybrids, observed cryptic pairing increased to a maximum of 10III although Z. mays × Z. mays with 2n = 30 did not show significant differences between treated and untreated materials. Pairing was also observed in species and hybrids with 2n = 40, in which a maximum of 10IV was observed, with the exception of Z. mays with 2n = 40 where treated and untreated cells did not differ significantly.

46 meganuclease i-SceI enhances stable transgene integration in cultured bovine fetal fibroblasts Ortega, Nicolás Matías; Benitez, S. B.; Barrionuevo, Blanca Elizabeth; Olmos Nicotra, Maria Florencia; Alessio, Ana Paula; Fili, Alejandro; Forcato, Diego Oscar; Stice, S. L.; Bosch, Pablo Production of genetically modified large animals through somatic cell nuclear transfer (SCNT) requires genetic manipulation of cultured cells, which are subsequently used as nuclear donors to generate a transgenic animal. Stable transgene integration into the donor cell genome is an inefficient process that involves integration of transgenes in randomly occurring DNA double-strand breaks. Therefore, our objective was to evaluate transient and stable transfection in cultured bovine fetal fibroblasts (BFF) using a transgenic strategy based on the simultaneous presence of a meganuclease (I-SceI) and a transgene flanked by restriction sites for I-SceI. Bovine fetal fibroblasts (2.63 × 104 cells cm–2 in 24-well plates) were co-transfected with a plasmid vector (pBSII-I-SceI-ZsGreen1-Neo) carrying expression cassettes for ZsGreen1 (fluorescent protein) and neomycin resistance flanked by restriction sites for I-SceI along with an expression plasmid for I-SceI (pCBASce). As controls, BFF were co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus a plasmid that lacks the I-SceI expression cassette (pCBA). Lipofectamine 2000 (Invitrogen) was used as the transfection reagent as per manufacturer’s instructions. Two different relationships of vector pBSII-I-SceI-ZsGreen1-Neo to pCBASce or pCBA (control) were tested: 1 : 1 and 1 : 3 (total amount of plasmid DNA per well was 500 ng). Transient transfection was evaluated by flow cytometry and reported as percentage of green fluorescent cells 72 h post-co-transfection. Stable integration of transgene sequences was assessed 21 days after co-transfection by determining the number of fluorescent cell colonies (FCC) that developed in selective media (DMEM + 250 µg mL–1 of G418). Data were analyzed by ANOVA and Tukey test and expressed as mean ± standard error of the mean. Flow cytometric analysis at 72 h post-transfection showed no statistical differences between the proportions of fluorescent cells in cultures co-transfected with pCBASce compared with those transfected with the control plasmid. The number of FCC developed from cultures co-transfected with pBSII-I-SceI-ZsGreen1-Neo plus pCBASce at a 1 : 1 ratio was 6.4-fold higher compared with those observed in the control group at the same ratio (8.00 ± 2.16 v. 1.25 ± 0.62 colonies; P < 0.05). However, there was no difference in the number of FCC formed at a plasmid ratio of 1 : 3 between the treatment (3.75 ± 1.03 colonies) and the control (2.70 ± 1.35 colonies; P > 0.05). Several transgenic BFF cell lines were generated by subculturing individual colonies. Polymerase chain reaction and Southern blotting confirmed that antibiotic-resistant and phenotypically positive colonies had integrated the ZsGreen1 transgene. Western blot analysis using an anti-HA antibody revealed a band of the expected size (30 kDa) in cells transfected with pCBASce. We conclude that I-SceI transgenesis significantly increases the functional integration of plasmid DNA into the bovine fibroblast genome as has been reported in embryos of other vertebrates, up to now by unknown mechanisms. This transgenic strategy should facilitate stable transfection of bovine fibroblasts to generate genetically modified animals though SCNT.

331 optimization of branched 25 kDa polyethylenimine for efficient gene delivery in bovine fetal fibroblasts Forcato, Diego Oscar; Olmos Nicotra, Maria Florencia; Ortega, Nicolás Matías; Alessio, Ana Paula; Fili, Alejandro; Rodriguez, Natalia Evelin; Bosch, Pablo Cost-effective, highly efficient, and noncytotoxic transfection of bovine fetal fibroblasts (BFF) has proven difficult to achieve by regular chemical and physical methods. The aims of this study were to evaluate transient transfection efficiency and toxicity of commercially available branched 25 kDa polyethylenimine (25 kDa PEI, Sigma-Aldrich, St. Louis, MO, USA) and to optimize the transfection conditions leading to high percentages of PEI-transfected fibroblasts with minimum cytotoxic effects. Bovine fetal fibroblast (BFF) cells were seeded a day before transfection in 24-well plates at a density of 3 × 104 cells per well in DMEM with antibiotics and 10% SFB. When 70 to 90% confluence was reached, cells were washed with PBS and incubated in DMEM without antibiotics or SFB. For the transfection-mix preparation, increasing amounts of plasmidic DNA (pZsGreen1; 2 to 6 µg) were added to 50 µL of DMEM without antibiotics or SFB, incubated for 5 min at room temperature, and complexed with 0.5 to 4 µg of PEI (from 1 mg mL–1 solution) in 50 µL of PBS for 10 min. This transfection mix was added to the cell cultures and, 2 h later, 500 µL of DMEM with antibiotics and 10% SFB was added to each well. Detection of green fluorescent protein (GFP) expression by flow cytometry (reported as percentage of green fluorescent cells) was performed 48 h after transfection. Results were analysed by ANOVA and Tukey test and expressed as mean ± SEM (P < 0.05). We found no significant difference between the percentage of GFP-positive cells transfected with 1 or 2 µg of 25 kDa PEI at 2 µg of DNA/well (15.2 ± 1.3 v. 16.9 ± 0.9%, respectively; P > 0.05), whereas cells transfected with 1 or 2 µg of low-molecular-weight PEI (2 kDa) showed extremely low transfection efficiencies. Increasing the DNA load up to 6 µg significantly enhanced cell transfection (3.5- and 6-fold comparing 2 µg v. 4 µg and 6 µg of DNA, respectively; P < 0.05) at 1 and 2 µg of 25 kDa PEI/well. In order to evaluate the cytotoxic effect of PEI, cell viability was determined using the MTT assay in 96-well plates (cells/well), with each condition scaled down to replicate the effect of 2 kDa or 25 kDa PEI in a 24-well plate. The MTT results (expressed as % of the control) indicated that PEI became cytotoxic at concentrations equivalent to 2 and 4 µg/well (54.7 ± 3.4 and 18.5 ± 5.7, respectively), whereas 1 µg/well produced a slight detrimental effect on cell viability (90.0 ± 2.6). No evidence of cytotoxicity was observed when the BFF were incubated with 0.5 µg/well of 25 kDa PEI and 1 or 2 µg/well of 2 kDa PEI. To study if a combination of low- and high-molecular-weight PEI could improve transfection efficiency and reduce toxicity, we tested a mixture (1 : 1) of 2 kDa and 25 kDa PEI. Even though the 1 : 1 mixture was less cytotoxic, the efficiency of gene delivery was not improved. We conclude that, under our experimental conditions, the highest percentage of GFP-expressing cells with good viability was obtained when 1 µg of 25 kDa PEI was added per well. Therefore, branched 25 kDa PEI transfection represents an efficient, simple, and cost-effective alternative for gene delivery in bovine fibroblast cells in culture.

Impact of structural and textural membrane properties on lemon juice clarification Chornomaz, Patricia Mariana; Pagliero, Cecilia Liliana; Marchese, Jose; Ochoa, Nelio Ariel Lemon juice was clarified using membranes with different structural and textural properties. Membranes were prepared from 0, 5, 7 and 10 wt.% of PVP in PVDF and they were structurally and functionally characterized. Results indicated that the addition of PVP produced both structural and surface textural changes in the membranes. These textural changes resulted in an increase of apparent hydrophobicity in the membranes prepared from 5 and 7% of PVP in the casting solution. Besides, the presence of residual PVP in the membrane favors hesperidin adsorption enhancing its retention. Analysis of the clarified juice indicated that the membrane prepared with 5% of PVP possessed the highest efficiency, combining high permeate flux and high juice quality.

Eficaz selección de espermatozoides bovinos criopreservados usando filtración por columnas de lana de vidrio; Efficient cryopreserved bovine sperm selection using glass wool filtration Vazquez, Monica Hebe; Marin Briggiler, Clara Isabel; Cetica, Pablo Daniel; Dalvit, Gabriel Carlos; Caballero, J. N.; Arzondo, Maria Matilde La criopreservación del semen es ampliamente utilizada en el manejo reproductivo bovino y permite la distribución y comercialización del material genético de esta especie. Sin embargo, los protocolos de congelación/descongelación afectan negativamente la calidad espermática, originando una alta proporción (más del 50%) de espermatozoides muertos y criocapacitados, no aptos para la fecundación. Para obtener espermatozoides funcionales es necesario realizar procedimientos de selección espermática. Recientemente hemos publicado un trabajo en la revista Theriogenology (2012; 78:201-209) que describe el uso de la filtración por columnas de lana de vidrio para la selección de espermatozoides funcionales a partir de semen bovino previamente congelado. El método es rápido, sencillo y económico, y permite seleccionar un alto porcentaje de espermatozoides vivos (94±3%), con motilidad progresiva (89±4%), no capacitados (80±10%), con el acrosoma intacto (98±1%) y que presentan alta capacidad de fecundar ovocitos in vitro. La técnica de filtración permite obtener un rendimiento del 67±19 %, ~4 veces mayor que el del método de Swim up. En conclusión, la filtración por columnas de lana de vidrio es una alternativa válida para las biotecnologías reproductivas bovinas, así como para otros animales domésticos y de granja y para especies en peligro de extinción.; Frozen bull semen is worldwide distributed and utilized in several assisted reproductive technologies. However, semen cryopreservation negatively affects sperm quality, rendering a high proportion (over 50%) of dead and cryocapacitated spermatozoa with low fertilizing potential. To obtain a population of functional spermatozoa, a selection procedure must be applied. Our group recently reported in the Theriogenology journal (2012; 78:201-209) a comprehensive study that demonstrates the effectiveness of the glass wool filtration procedure to select functional spermatozoa from frowen-thawed semen samples in a fast, low-cost and simple fashion. High percentages of live spermatozoa (94±3%), with progressive motility (89±4%), mainly non- capacitated (80±10%), with intact acrosomes (98±1%), and capable to fertilize oocytes in vitro were recovered in the filtrate. The glass wool sperm filtration procedure rendered a yield of 67±19%, ~4 times higher than the Swim up. In conclusion, sperm filtration through glass wool columns is a valid alternative to be incorporated in the bull reproductive technologies, and may be suitable for other domestic and farm animals as well as to endangered species.

Responsabilidad civil de directores de instituciones financieras en el derecho societario en los Estados Unidos Miguens, Héctor José Estudio de la responsabilidad civil de directores de entidades financieras (entre ellas de bancos comerciales) en el derecho de los Estados Unidos de America conforme a las normas de la jurisprudencia y de ordenamientos estatutarios sobre la cuestión.; In this paper the author studies the cases treated by local and federal case law and statutes in the United States of America on the issue of liability of directors of financial institutions (mainly banks). The work studies the most important court cases and books and articles by authors specializing in the issue of liability of directors of companies, especially financial institutions in the United States of America. In the final part the author highlights the key findings of the investigation.

Implicancias de la resignificación de la espacialidad en las categorías de análisis geográfico. La revalorización del territorio como constructo social; Implications of the resignification of spatiality in the categories of geographic analysis. The revaluation of the territory as a social construct Valenzuela, Cristina Ofelia; Figueroa, Maria Laura Con el presente trabajo nos proponemos aportar a la reflexión acerca del impacto de la re-significación de la espacialidad en las categorías de análisis geográfico, con particular énfasis en la del territorio y la territorialidad. Para ello examinamos, en primer lugar, el creciente eclecticismo del “espacio geográfico” en las distintas corrientes de pensamiento coexistentes en la disciplina geográfica que puede ser calificada de “multiparadigmática”. También reflexionamos sobre el efecto del redimensionamiento de las principales categorías analíticas, poniendo particular atención en la revalorización del territorio como construcción humana. Se aporta un ejemplo de esta categoría analítica de fundamental importancia para la geografía, examinando la compleja convivencia de territorialidades que genera el usufructo económico en espacios compartidos por actores con distintas lógicas de aprovechamiento de los recursos.; The present paper intends to contribute to the reflection on the impact of the re-significance of the spatiality in the categories of geographic analysis, with particular emphasis on territory and territoriality. So, we examine, in the first place, the increasing eclecticism of “geographic space” in different currents of valid thought coexisting in geographical discipline that can be described as “multiparadigmatic”. We also reflect on the effect of the new meanings of the main analytical categories with special attention to the revaluation of the territory as a human construction. And we provide an example of this analytical category of fundamental importance for Geography, by examining the complex coexistence of territorialities that generates the economic usufruct in spaces shared by actors with distinct ideas about the use of resources.

Tipos sociales característicos del Chaco Territoriano (1884-1950). Sus condiciones de vida, e influencia en la identidad de este espacio; Social types characteristic of the Chaco Territoriano (1884-1950). Their conditions of life, and influence on the identity of this space Mari, Oscar Ernesto La ocupación del Chaco Austral Argentino entre fines del siglo XIX y primeras décadas del XX, fue impulsada por sucesivas etapas colonizadoras que acompañaron la alternancia de ciclos económicos diferenciados. En cada uno de estos momentos, que se dieron en ámbitos geográficos diferentes dentro del Territorio, fueron formándose cuerpos sociales particulares que aportaron los primeros rasgos identitarios a esta sociedad en formación. Dentro de éstos, surgieron “tipos sociales” que motivaron las primeras imágenes con que la sociedad nacional identificó al Chaco. Las condiciones de vida y trabajo, y el aporte cultural de algunos sectores representativos del ámbito rural del Chaco en esta época, son temas abordados en el presente artículo.; The occupation of the Southern Chaco Argentine between ends of the nineteenth century and early decades of the 20th, was boosted by successive phases colonizers that they accompanied differentiated economics cycles. In each one of these moments, that were given in different geographic areas within the Territory, went forming social groups individuals that contributed the first identity traits to this society in training. Within these, emerged social types that motivated first images with that the domestic society identified to Chaco. Living conditions and work, and it contributes the cultural of some sectors representing the rural field of Chaco in this period, are issues addressed in the current article.

Fuentes y métodos para el estudio de las élites capitulares en Corrientes colonial Salinas, Maria Laura; Pozzaglio, Fernando Ariel En este trabajo se pretende realizar una aproximación a las características de la élite capitular y encomendera que surgió y se desarrolló en Corrientes a lo largo del periodo colonial. Para esto, se conceptualiza el término élite de acuerdo con los clásicos (como Pareto, Mosca, Michels) que estudiaron el tema para observar si es posible o no denominar de este modo al grupo social superior correntino de este periodo. Además se recurre a los aportes en esta cuestión realizados por otros autores, como Michel Bertrand, que estudiaron los grupos elitistas coloniales de otras localidades hispanoamericanas. Del mismo modo, se señala como método adecuado para abordar esta cuestión la prosopografía y, por último, se indica cuáles son la documentación disponible y en qué Archivos nacionales e internacionales se los puede ubicar.

Fotografía, testimonio oral y memoria: (re)presentaciones de indígenas e inmigrantes del Chaco (Argentina); Photography, oral testimony and memory: (re)presentation of indigenous and immigrants in Chaco (Argentina) Giordano, Mariana Lilian Este artículo propone un análisis de las representaciones visuales sobre indígenas e inmigrantes del Territorio Nacional del Chaco (Argentina), a partir de las huellas de enunciación y las narrativas visuales que se construyeron en/a través de la fotografía. Las lecturas actuales de ese corpus fotográfico, desde experiencias de recepción, permiten que el testimonio oral actualice las percepciones históricas. Con ello buscamos explorar, por un lado, cómo es representado cada grupo socio-étnico y de qué modo esas representaciones se convierten en memorias visuales de sus comunidades. Por el otro, procuramos indagar sobre las correspondencias y/o contradicciones entre lo que las narrativas fotográficas históricas (re)presentan, como referentes de memorias visuales, y lo que los receptores actuales identifican o (des)conocen, como parte de memorias identitarias en construcción, en una Provincia que desde el discurso político-cultural se busca mostrar como un crisol de raza.; This paper analyses the visual representations of indigenous and immigrants located on Territorio Nacional del Chaco (National Territory of Chaco), Argentina, based on traces of enunciation and visual narratives constructed in/ through photography. The current readings of this photographic material, from experiences of reception, allowed the updating of historical perceptions through the oral testimony. In this way, we first explore how each ethnic group is represented and how these representations became visual memories of their communities. Furthermore, we search for correlations or contradictions between what the historical photographic narratives (re)presented, as references of visual memory, and what current receivers identify o do not acknowledge as part of their identities and memories under construction, in a Province considered a melting pot by the political and cultural discourse.

Del fundamento pasivo y traumático del significar: Levinas y Lacan Leconte, Mariana El lenguaje como significación o sentido está en lugar de otra cosa que falta. Responde al vacío central -traumático- del campo del goce. Es suplencia fallida y, por lo tanto, al mismo tiempo reveladora de la falta que intenta suplir. En razón de esta función de suplencia, el lenguaje se encuentra estructuralmente alienado en el campo del goce. El intento de este artículo es dar cuenta de estas tesis del psicoanálisis lacaniano y extraer de ellas algunas precisiones para la comprensión de la diferencia entre Decir y Dicho en la fenomenología levinasiana del lenguaje, particularmente en lo que atañe a la articulación del orden sensible (vulnerabilidad) y el orden de las significaciones ideales.; The language as significance or sense is in the place of something that is absent. It responds to the central -traumatic- gap of the enjoyment's field. It is a failed substitute and, therefore and at the same time, it reveals the lack that he intends to replace. Because of this function of substitution, the language is, in a structural way, alienated in the enjoyment's field. The intention of this article is to explain these theories of lacanian psychoanalysis and to extract some precisions for the comprehension of the difference between Saying and Said in levinasian phenomenology of language, particularly in what concerns to the articulation of sensible order (vulnerability) and the order of ideal significances.

Pequeños mamíferos predados por la Lechuza de Campanario (Tyto alba) en la ecorregión del Chaco Seco en el noroeste argentino; Small mammals predated by the common Barn-owl (Tyto alba) in the Chaco Seco ecoregion in northwestern Argentina Gomez, Maria Daniela; Fontanarrosa, Gabriela; Ortiz, Pablo Edmundo; Jayat, Jorge Pablo Los hábitos tróficos de la Lechuza de Campanario (Tyto alba) han sido ampliamente estudiados en el centro y sur de Argentina. Sin embargo, en el noroeste los estudios son escasos. Se estudió la dieta de esta rapaz mediante el análisis de egagrópilas colectadas en seis localidades de la ecorregión del Chaco Seco. Se determinaron taxonómicamente los restos cráneo-dentarios encontrados y se calcularon para cada localidad el número mínimo de individuos, la frecuencia relativa y el porcentaje de biomasa aportado a la dieta por cada ítem presa. Se calcularon, además, la amplitud de nicho trófico y la amplitud de nicho trófico estandarizada, el promedio geométrico de los pesos de las presas y la diversidad. Se obtuvo un total de 1231 ítems presa, en su mayoría pertenecientes al género Calomys, dominante en cinco de las seis localidades. La abundancia de individuos varió entre 83-508 y en todas las localidades dos especies (Calomys cf. C. venustus/ fecundus y Calomys cf. C. laucha/musculinus) aportaron más del 50% de la biomasa consumida. La amplitud de nicho trófico estandarizada osciló entre 0.111-0.661. El promedio geométrico de los pesos fue inferior al establecido para el Neotrópico. La abundancia de Calomys spp. en la dieta estuvo positivamente relacionada con el grado de transformación de la tierra en agroecosistemas, mientras que la diversidad de especies estuvo negativamente relacionada. Los resultados de este estudio aportan datos novedosos para la ecorregión del Chaco Seco en el noroeste argentino, confirmando los patrones establecidos para la Lechuza de Campanario en otras regiones de Argentina.; Trophic habits of the Common Barn-Owl (Tyto alba) have been widely studied in Argentina, mainly in the center and south of the country. However, in the north-western region these studies are scarce. We studied the diet of this raptor by analyzing pellets collected in six localities of the Chaco Seco ecoregion. Cranial remains were taxonomically determined, and the minimal number of individuals, relative frequency and percent biomass of each prey item were calculated. Moreover, we calculated food-niche breadth and standardized food-niche breadth, the geometric mean of prey weight, and the diversity. We obtained 1231 prey items, mainly of the genus Calomys, which was dominant in five of the six localities. Number of individuals varied among 83-508 and at all localities, two species (Calomys cf. C. venustus/ fecundus and Calomys cf. C. laucha/musculinus) contributed more than 50% of the consumed biomass. Standardized food-niche breadth varied between 0.111-0.661. Geometric mean of prey weight was lower than the established value for the Neotropical Region. The abundance of Calomys spp. in the diet was positively related to the degree of transformation of natural lands into agroecosystems, whereas species diversity was negatively related. These results contribute with novel data for the Chaco Seco ecoregion in northwestern Argentina, supporting the patterns found for the Common Barn-Owl in other regions of the country.

Ecological and climatic controls of modern wildfire activity patterns across southwestern South America Holz, Andrés; Kitzberger, Thomas; Paritsis, Juan; Veblen, Thomas Understanding how patterns of wildfire activity across biomes are shaped by heterogeneity in biomass resources to burn and atmospheric conditions conducive to burning is a high research priority in the context of global environmental change. Along a latitudinal gradient (25 to 56° S) from semi-arid scrublands through Mediterranean-type vegetation to wet forests in southwestern South America (SSA) we analyzed influences of mean climate and interannual climate variability on fire activity using documentary fire records from 1984 to 2008. We identified large regions with common temporal variability in annual area burned, related this variability to local interannual climate variability and in turn to modes of the major tropical and extratropical climate drivers of the southern hemisphere-El Niño-Southern Oscillation (ENSO) and the Antarctic Oscillation (AAO). Differences in fire activity response to interannual climate variability were related to the relative influences of available biomass to burn, and to weather effects on amounts of fine fuels and fuel moisture conditions. The pattern of average fire activity along this latitudinal moisture/productivity gradient corresponds well with the varying constraints model. This model predicts low fire activity towards the arid extreme due to reduced burnable biomass and again towards the humid extreme due to infrequent weather suitable for drying fuels, and predicts a broad zone of high fire activity at intermediate locations where resources to burn are abundant in all years and fuel moisture dries under reliably dry summer conditions. The dominant influence on interannual climate variability is AAO, which explained most of the variability in fire activity both by reducing seasonal precipitation in mesic and wet forests where fire is dependent on infrequent drought and by enhancing fine fuel production in Mediterranean-type vegetation where fuel amount and continuity constrain fire activity. In the context of the drying and warming trends in SSA related to the continued positive anomaly in AAO, our results underscore the importance of the varying constraints on fire activity and modulation of fire-climate relationships by different vegetation types, which is a much needed step toward developing fire projections under future climate.

Primeros estudios sobre manufactura cerámica de contextos coloniales del sur de Pozuelos (puna de Jujuy, Argentina) Angiorama, Carlos Ignacio; Perez Pieroni, María Josefina En este trabajo se presentan los resultados de los primeros estudios sobre material cerámico procedente de tres contextos coloniales del sur de Pozuelos. Los estudios fueron abordados desde una perspectiva tecnológica, efectuando observaciones macroscópicas y submacroscópicas sobre atributos vinculados a la secuencia de manufactura, incluyendo aspectos morfológicos y de pastas. En base a los resultados obtenidos, se realizaron comparaciones con materiales prehispánicos previamente analizados, pudiéndose detectar algunas continuidades en la producción, como así también algunas discontinuidades. El predominio de continuidades en la alfarería analizada permite afirmar que al menos este tipo de cultura material de los habitantes coloniales de los contextos por nosotros estudiados no habría sufrido grandes cambios con respecto a época prehispánica.; Neste trabalho apresentam-se os resultados dos primeiros estudos sobre material cerâmico procedente de três contextos coloniais do sul de Pozuelos. Os estudos foram abordados desde uma perspectiva tecnológica, efetuaram-se observações macro e submacroscópicas sobre atributos vinculados à sequência de manufatura, incluindo aspectos morfológicos e de pastas. Na base dos resultados obtidos, realizaram-se comparações com materiais pré-hispânicos previamente analisados, detectando assim algumas continuidades na produção, como também algumas descontinuidades. O predomínio das continuidades na cerâmica analisada permite afirmar que a cultura material dos habitantes coloniais dos contextos estudados não teria sofrido grandes câmbios com respeito à época pré-hispânica.; The results of the first studies on ceramic materials from three colonial contexts of south Pozuelos are presented here. These studies were undertaken from a technological perspective. Macroscopic and sub macroscopic observations on attributes related to the production sequence were made, including pastes attributes, morphology and surface characteristics. The results, when compared to previous analysis of prehispanic materials, allowed identifying several continuities in the production of prehispanic and colonial pottery, as well as some discontinuities. The prevalence of the continuities in the analyzed pottery allows stating that the material culture from the studied colonial contexts had not gone through great changes since prehispanic times.

An independent limit on the axion mass from the variable white dwarf star R548 Corsico, Alejandro Hugo; Althaus, Leandro Gabriel; Romero, Alejandra Daniela; Mukadam, A.; García Berro, Enrique; Isern, Jordi; Kepler, S. O.; Corti, Mariela Alejandra Pulsating white dwarfs with hydrogen-rich atmospheres, also known as DAV stars, can be used as astrophysical laboratories to place contraints on the properties of funtamental particles like axions, by measuring their cooling rates and searching for extra cooling sources. In this paper, we present an independent inference of the mass of the axion using the most recent determination of the rate of change of the period of the largest amplitude mode (213 s) of R548, the prototype of this class of stars. This is done employing a state- of-the-art code which allows us to perform a detailed asteroseismological fit based of fully evolutionary sequences. The inclusion of the axions in the evolutionary sequences notably influences the evolutionary timescales, and thus the pulsational properties of these stars. In particular, the rates of period change of the modes are remarkably affected. This allows us to compare the theoretical values with the observed rate of period change of R548. We found that, if the period at 213 s of R548 is associated to a pulsation mode trapped in the hydrogen envelope, then the models indicate the existence of extra cooling in this pulsating white dwarf, consistent with axions of mass ma cos2 β aprox. 17.1 meV, in full agreement with the value inferred from another well-studied variable white dwarf with hydrogen-rich atmosphere, G117-B15A. Thus, we now have two independent estimates of the mass of the axion obtained from pulsating white dwarfs, which agree each other, although additional studies of other pulsating white dwarfs are needed to confirm this value of the axion mass.

Structural study, coordinated normal analysis and vibrational spectra of 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone Lizarraga, Emilio Fernando; Romano, Élida; Rudyk, Roxana Amelia; Catalan, Cesar Atilio Nazareno; Brandan, Silvia Antonia Structural and vibrational properties of 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone, isolated from Senecio nutans Sch. Bip. (Asteraceae) were studied by infrared and Raman spectroscopies in solid phase.The Density Functional Theory (DFT) method together with Pople’s basis set show seven stable conformers for the compound in the gas phase and that only two conformations are probably present in the solid phase. The harmonic vibrational wavenumbers for the optimized geometry were calculated at B3LYP/6-31G⁄and B3LYP/6-311++G⁄⁄ levels. For a complete assignment of the vibrational spectra, DFT calculations were combined with Pulay´ s Scaled Quantum Mechanics Force Field (SQMFF) methodology in order to fit the theoretical wavenumber values to the experimental ones. Then, a complete assignment of all the observed bands in the vibrational spectra was performed. The natural bond orbital (NBO) study reveals the characteristics of the electronic delocalization of the two stable structures, while the corresponding topological properties of electronic charge density were analyzed by employing Bader’s Atoms in the Molecules theory (AIM).

Evaluación de los conocimientos en Salud Oral: Revisión de la Literatura Dho, María Silvina; Palladino, Alberto Constantino El objetivo del presente trabajo fue realizar una revisión de la literatura científica para identificar los estudios realizados sobre "los conocimientos en salud oral"; el instrumento de recolección de datos utilizado en cada caso y las dimensiones consideradas para su valoración. Se procedió a la búsqueda de artículos científicos publicados en los últimos años en las bases de datos Pubmed, Dentistry & Oral Sciences Source de Ebsco y Scielo. Se trabajó con un total de treinta y cinco artículos científicos y se identificaron estudios realizados en "Gestantes"; "Madres, padres y cuidadores de niños en edad preescolar"; "Escolares: niños y adolescentes"; "Estudiantes universitarios"; "Profesionales"; "Individuos que padecen diabetes". Los estudios utilizaron como instrumento metodológico encuestas especialmente diseñadas para cada estudio particular, o ya utilizadas y validadas en otras investigaciones. Las dimensiones para valorar "los conocimientos de salud oral" consideradas en la mayor parte de las investigaciones fueron: factores etiológicos y métodos preventivos de la caries dental y de la enfermedad gingivoperiodontal, higiene bucodental, el flúor como método preventivo de caries dental, cariogenicidad de ciertos alimentos, consulta odontológica.; The aim of this study was to review the scientific literature to identify studies about «oral health knowledge”, the data collection instrument used in each case and the dimensions considered for its evaluation. Science Papers published in the last years in the Pubmed database, Dentistry & Oral Sciences Source Ebsco and Scielo were researched. We worked with a total of thirty-five scientific articles and studies performed in «Pregnant Mothers”; «Mothers, fathers and preschoolers caretakers”; «Schoolers: Children and Adolescents, «College Students», «Professionals” , «People who suffer from diabetes” were identified. As a methodological instrument, the studies used surveys, specially designed for each particular study, or previously used and validated in other research works. Dimensions to assess «oral health knowledge» considered in most of the research woks were: etiological aspects and preventive methods of dental caries and gingivoperiodontal disease, oral hygiene, fluoride as preventive method of dental caries, cariogenicity of certain foods, and dental checkups.

Range of semilinear operators for systems at resonance Amster, Pablo Gustavo; Kuna, Mariel Paula For a vector function u : R → RN we consider the system u 00(t) + ∇G(u(t)) = p(t) u(t) = u(t + T), where G : RN → R is a C1 function. We are interested in finding all possible T-periodic forcing terms p(t) for which there is at least one solution. In other words, we examine the range of the semilinear operator S : H2 per → L2 ([0, T], RN ) given by Su = u 00 + ∇G(u), where H2 per = {u ∈ H2 ([0, T], R N ); u(0) − u(T) = u 0 (0) − u 0 (T) = 0}. Writing p(t) = p + pe(t), where p := 1 T R T 0 p(t) dt, we present several results concerning the topological structure of the set I(pe) = {p ∈ R N ; p + pe ∈ Im(S)}.