An experimental and DFT study of a disulfide-linked Schiff base: Synthesis, characterization and crystal structure of bis (3-methoxy-salicylidene-2-aminophenyl) disulfide in its anhydrous and monohydrate forms Ferraresi Curotto, Verónica; Echeverría, Gustavo Alberto; Piro, Oscar Enrique; Pis Diez, Reinaldo; Gonzalez Baro, Ana Cecilia A detailed structural and spectroscopic study of the disulfide Schiff base obtained from condensation of 2-aminothiophenol and o-vanillin is reported. It includes the analyses of the anhydrous and monohydrate forms of the title compound. Structures of both solids were resolved by X-ray diffraction methods. A comparison between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. Vibrational (IR and Raman) and electronic spectra were measured and assigned with the help of computational methods based on the Density Functional Theory. Calculated MEP-derived atomic charges were calculated to predict coordination sites for metal complexes formation.

Demographic and breeding performance of a new kelp gull Larus dominicanus colony in Patagonia, Argentina; Demografía y desempeño de la reproducción en una nueva colonia de gaviota cocinera Larus Dominicanus en la Patagonia, Argentina Lisnizer, Nora; Garcia Borboroglu, Jorge Pablo; Yorio, Pablo Martin Understanding the processes involved in the establishment and persistence of new seabird colonies is important for improving conservation and management strategies. Over the past few decades, kelp gull Larus dominicanus numbers have increased in Patagonia, Argentina, and new colonies have been reported. We studied a recently established colony to analyze aspects of its population dynamics and breeding biology. The number of breeding pairs at Punta Loma increased from 13 to 233 in the seven years after the colony was established (2004-2011) and number of chicks fledged per nest was low (<1 chick per nest) compared to that of other old-established kelp gull colonies in the region. Modelled estimates of abundance assuming closed population dynamics for the Punta Loma colony were lower than observed (70% lower or more), suggesting that the observed growth cannot be explained by local productivity alone. Immigration from other colonies was likely the main factor responsible for the observed growth, being considerably higher than local recruitment. This study constitutes the first characterization of demographic processes occurring during the initial years since colony establishment in kelp gulls. Main findings include rapid population growth driven by immigration and poor breeding performance potentially linked to a high proportion of young breeders. Our results highlight the key role of source-sink dynamics on the growth and persistence of new seabird colonies.; La comprensión de los procesos involucrados en el establecimiento y la persistencia de nuevas colonias de aves marinas es importante para mejorar las estrategias de manejo y conservación. Durante las últimas décadas, los números de gaviota cocinera Larus dominicanus en Patagonia, Argentina, se han incrementado y se han formado nuevas colonias. Estudiamos una colonia establecida recientemente para analizar aspectos de su dinámica poblacional y biología de reproducción. El número de parejas reproductoras en Punta Loma se incrementó de 13 a 233 en los siete años posteriores al establecimiento de la colonia (2004–2011) y el número de pollos independizados por nido fue bajo (< 1 pollo por nido) en comparación a otras colonias más antiguas de la región. Las estimaciones de abundancia obtenidas de un modelo que asume una dinámica poblacional cerrada para la colonia de Punta Loma fueron menores que las observadas (70% menores o más), sugiriendo que el crecimiento observado no puede ser explicado únicamente por productividad local. La inmigración desde otras colonias fue posiblemente el principal factor responsable del crecimiento observado, siendo considerablemente mayor al reclutamiento local. Este estudio constituye la primera caracterización de los procesos demográficos que ocurren durante los primeros años desde el establecimiento de una colonia en gaviotas cocineras. Los principales resultados incluyen un rápido crecimiento poblacional favorecido por la inmigración y un pobre rendimiento reproductivo potencialmente asociado a una elevada proporción de reproductores jóvenes. Nuestros resultados resaltan el papel clave de la dinámica de tipo fuente-sumidero en el crecimiento y persistencia de colonias nuevas de aves marinas.

A conceptual model and technological support for organizational knowledge management Ale, Mariel Alejandra; Toledo, Carlos Manuel; Chiotti, Omar Juan Alfredo; Galli, Maria Rosa Knowledge Management (KM) models proposed in the literature do not take into account all necessary aspects for effective knowledge management. First, to address this issue, this paper presents a set of requirements that any KM model or initiative should take into account to cover all aspects implied in knowing processes. These requirements were identified through a critical and evolutionary analysis of KM. Second; the paper presents a new distributed KM Conceptual Model whose building blocks are the knowledge activities involved in knowing processes. These activities are: knowledge creation, knowledge sharing, and knowledge representation and retrieval. This model provides a holistic view of KM whose purpose is helping managers understand the scope of this initiative, and supplying a guide for research and implementation in organizations. In this sense, the model presents KM as a highly social rather than technological process. Third; the paper briefly describes an architecture to provide a technological support for knowledge representation and retrieval activities of the proposed KM Conceptual Model. This architecture allows implementing a distributed organizational memory that helps to represent the knowledge context through an ontological model, providing a local perspective of each knowledge domain within the organization. Strategies for knowledge annotation, knowledge retrieval, and ontology evolution are briefly described and results of preliminary performance analysis are shown. Finally; based on the available literature, a comparative analysis of different KM models shows their adequacy for previously presented requirements.

Two new species of Nyctelia Latreille (Coleoptera: Tenebrionidae) from Argentinean Patagonia with zoogeographical and ecological remarks Flores, Gustavo Ernesto; Cheli, German Horacio Two new species of the genus Nyctelia Latreille (Pimeliinae: Nycteliini) from Argentinean Patagonia, N. sulcogranata sp. nov. and N. recteplicata sp. nov. , are described. Distributional maps, habitus, photographs and illustrations of genitalic features for these two new species are included, with comparisons to other known species of the genus. A discussion is presented on distributional habitat records and biogeography.

Comparación urbano-rural de parámetros meteorológicos en la ciudad de Tandil, Argentina Picone, Natasha; Campo, Alicia María En la ciudad de Tandil se encuentran en desarrollo estudios para conocer el clima urbano de la misma y este trabajo cubre algunos de los aspectos del mismo. El objetivo principal es realizar una comparación urbano-rural de ocho parámetros meteorológicos en un año (julio de 2010-junio de 2011). Para ello se utilizaron datos meteorológicos obtenidos de la estación meteorológica Tandil del Servicio Meteorológico Nacional (datos rurales) y de una estación meteorológica automática que pertenece al CIG (datos urbanos). A partir de la comparación se observó una clara influencia urbana sobre todos los parámetros analizados en un año marcado por el efecto Niña.; In Tandil city are taking place several studies to learn about its urban climate, this work is part of them. The main objective is to compare urban - rural differences in eight meteorological parameters during a year (July 2010 - June 2011). There where use weather data from Tandil meteorological station of the Servicio Meteorológico Nacional (rural data) and from an automatic meteorological station (urban data). As a result of the comparison the urban influence was detected in all the parameters analyzed during a year with Niña effect.

El migrante en Argentina y el acceso a sus derechos: un breve recorrido por las normas, las políticas y sus historias; The migrant in Argentina and the access to their rights: a brief overview of the rules, the policies and their stories Gómez, Abigail Gabriela; Piana, Ricardo Sebastián Diariamente llegan a Argentina inmigrantes provenientes de países vecinos, con deficiencias para acceder a sus derechos en su país de origen. El Estado argentino debió realizar diversas medidas para protegerlos, sancionando normativa acorde a la incorporación de los Tratados y Pactos internacionales y realizando políticas y acciones públicas en clave de derechos humanos. Simultáneamente se pueden observar obstáculos a la hora de acceder efectivamente a esos derechos en pie de igualdad con los ciudadanos. Resulta pertinente analizar cómo estas personas ven satisfechos sus derechos al llegar al país utilizando, como estrategia metodológica, un estudio etnográfico. El análisis se dividirá en dos partes; se describirá cuáles son las herramientas con las que cuentan los migrantes a la hora de intentar acceder a esos derechos humanos básicos y se conocerá, mediante el análisis de fallos judiciales, entrevistas y documentos de ONGs abocadas a la temática, si efectivamente se cumple con la satisfacción de esos derechos. Como resultado se evidencia que si bien los inmigrantes encuentran en Argentina el acceso gratuito a las prestaciones que en sus países les es difícil alcanzar, existen insuficiencias cuantitativas y cualitativas de los servicios del Estado argentino, especialmente en el sistema sanitario y educativo.; Argentina receives immigrants from neighboring countries with serious deficiencies as regards their rights. The Argentinean government had to implement different policies to protect them, incorporating international treaties on human rights in their internal legal system and making public policies. Simultaneously, obstacles can be observed, when having access to these rights on an equal condition with Argentinean citizens. It is pertinent to analyze this situation using a methodological tool like an ethnographic study. The analysis will be divided into two parts, on the one hand, the migrant’s tools to have access to these basic human rights will be described, and on the other hand, it will be analyzed through court decisions, interviews and NGOs documents, if those rights are indeed satisfied. As a result, it is evident that while immigrants in Argentina have free access to benefits which in their countries are difficult to achieve, there are, still quantitative and qualitative inefficiencies, especially in health and education.

Alkaloids from Habranthus tubispathus and H. jamesonii, two amaryllidaceae with aAcetyl- and butyrylcholinesterase inhibition activity Cavallaro, Valeria; Alza, Natalia Paola; Murray, María Gabriela; Murray, Ana Paula Alzheimer´s disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. Plants of the Amaryllidaceae family are known to synthesize alkaloids, which have shown AChE inhibitory activity. Habranthus tubispathus and H. jamesonii are two Amaryllidaceae that can be found growing wild to the southwest of Buenos Aires in Argentina. Acetyl- and butyrylcholinesterase inhibition was observed for the extracts obtained from bulbs of H. tubispathus and bulbs and aerial parts of H. jamesonii. The strongest cholinesterase inhibition was observed for the alkaloid extract obtained from the aerial parts for H. jamesonii (AChE IC50= 0.7 µg/mL; BChE IC50= 6.7 µg/mL). The AChE inhibition observed for H. jamesonii could be explained by the presence of galanthamine and sanguinine, two potent AChE inhibitors. The levels of lycorine and hippeastidine, moderate AChE inhibitors, observed in the bulbs of H. tubispathus could be responsible for the significant AChE inhibition observed. The alkaloids present in these Amaryllidaceae were identified by means of GC-MS analysis. In the case of H. tubispathus, hippeastidine and 3-O-demethylhippeastidine, were isolated and completely characterized by 1H and 13C NMR spectroscopy.

The family Caecidae (Gastropoda: Caenogastropoda) in Argentine waters Pastorino, Guido; Chiesa, Ignacio Luis This is the first formal report of members of the family Caecidae in Argentine waters. Caecum striatum de Folin, 1868, C. strigosum de Folin, 1868, and C. achirona (de Folin, 1867) are re-described from shallow waters off Piedras Coloradas ( 4053.0810 S, 6507.5920 W), Rı´o Negro Province, Argentina. This is the farthest south record of these species which were previously recorded from USA, Bahamas, Panama, Brazil, and Uruguay. The authors also make observations about the different ontogenetic stages of the studied species. Scanning electron microscope illustrations of radula and operculum are provided for the first time.

Categorías: los 30 primeros años Dubuc, Eduardo Julio El lector debe tener en cuenta que esta recopilación de los 30 primeros años de vida de la teoría de categorías responde a lo que puedo recordar, y no es el resultado de una investigación histórica sobre el desarrollo de la misma. El relato tiene como hilo conductor las veintiuna referencias primarias que aparecen por orden cronológico al final del artículo, las secundarias irán en notas a pie de página. Asimismo, he querido que estas notas sean un fiel reflejo de la conferencia impartida en octubre de 2013 en la ENHEM 41 , de contenido acotado por el tiempo, y no incluyen ni más ni menos que lo allí dicho. Quiero agradecer a los organizadores de la ENHEM 4, y en particular a Luis Recalde, el haberme invitado a la Escuela, sin lo que este trabajo nunca hubiese visto la luz.

NetMHCstab – predicting stability of peptide–MHC-I complexes; impacts for cytotoxic T lymphocyte epitope discovery Jørgensen, Kasper W.; Rasmussen, Michael; Buus, Søren; Nielsen, Morten Major histocompatibility complex class I (MHC-I) molecules play an essential role in the cellular immune response, presenting peptides to cytotoxic T lymphocytes (CTLs) allowing the immune system to scrutinize ongoing intracellular production of proteins. In the early 1990s, immunogenicity and stability of the peptide–MHC-I (pMHC-I) complex were shown to be correlated. At that time, measuring stability was cumbersome and time consuming and only small data sets were analysed. Here, we investigate this fairly unexplored area on a large scale compared with earlier studies. A recent small-scale study demonstrated that pMHC-I complex stability was a better correlate of CTL immunogenicity than peptide–MHC-I affinity. We here extended this study and analysed a total of 5509 distinct peptide stability measurements covering 10 different HLA class I molecules. Artificial neural networks were used to construct stability predictors capable of predicting the half-life of the pMHC-I complex. These predictors were shown to predict T-cell epitopes and MHC ligands from SYFPEITHI and IEDB to form significantly more stable MHC-I complexes compared with affinity-matched non-epitopes. Combining the stability predictions with a state-of-the-art affinity predictions NetMHCcons significantly improved the performance for identification of T-cell epitopes and ligands. For the HLA alleles included in the study, we could identify distinct sub-motifs that differentiate between stable and unstable peptide binders and demonstrate that anchor positions in the N-terminal of the binding motif (primarily P2 and P3) play a critical role for the formation of stable pMHC-I complexes. A webserver implementing the method is available at www.cbs.dtu.dk/services/NetMHCstab.

An Observing System Simulation Experiment (OSSE) for the Aquarius/SAC-D soil moisture product Bruscantini, Cintia Alicia; Crow, Wade T.; Grings, Francisco Matias; Perna, Pablo Alejandro; Maas, Martín Daniel; Karszenbaum, Haydee An Observing System Simulation Experiment (OSSE) for the Aquarius/SAC-D mission has been developed for assessing the accuracy of soil moisture retrievals from passive L-band remote sensing. The implementation of the OSSE is based on the following: a 1-km land surface model over the Red-Arkansas River Basin, a forward microwave emission model to simulate the radiometer observations, a realistic orbital and sensor model to resample the measurements mimicking Aquarius operation, and an inverse soil moisture retrieval model. The simulation implements a zero-order radiative transfer model. Retrieval is performed by direct inversion of the forward model. The Aquarius OSSE attempts to capture the influence of various error sources, such as land surface heterogeneity, instrument noise, and retrieval ancillary parameter uncertainty, all on the accuracy of Aquarius surface soil moisture retrievals. In order to assess the impact of these error sources on the estimated volumetric soil moisture, a quantitative error analysis is performed by comparison of footprint-scale synthetic soil moisture with “true” soil moisture fields obtained from the direct aggregation of the original 1-km soil moisture field input to the forward model. Results show that, in heavily vegetated areas, soil moisture retrievals have a positive bias that can be suppressed with an alternative aggregation strategy for ancillary parameter vegetation water content (VWC). Retrieval accuracy was also evaluated when adding errors to 1-km VWC (which are intended to account for errors in VWC derived from remote sensing data). For soil moisture retrieval root-mean-square error on the order of 0.05 m3/m3, the error in VWC should be less than 12%.

The role and status of English in Spanish-speaking Argentina and its education system: nationalism or imperialism? Porto, Melina There is a lot of controversy nowadays in the field of English Language Teaching (ELT) in the context of Teaching English to Speakers of Other Languages (TESOL) regarding the status and role of English in non-English speaking countries, in particular in developing countries, as well as in English-speaking countries with a history of colonialism. In these settings, the discourse of English as a form of imperialism requires a reconsideration of the role and status of English in the national school curriculum in primary and secondary school contexts. It also requires the exploration of the connections with nationalism and national identity, for within this discourse of imperialism, English tends to be seen as detrimental to the national identity, which education explicitly aims to form and develop through formal schooling.

Prenatal stress changes the glycoprotein GPM6A gene expression and induces epigenetic changes in rat offspring brain Monteleone, Melisa Carolina; Adrover, Ezequiela; Pallares, Maria Eugenia; Antonelli, Marta Cristina; Frasch, Alberto Carlos C.; Brocco, Marcela Adriana Prenatal stress (PS) exerts strong impact on fetal brain development and on adult offspring brain functions. Previous work demonstrated that chronic stress alters the mRNA expression of GPM6A, a neuronal glycoprotein involved in filopodium extension. In this work, we analyzed the effect of PS on gpm6a expression and the epigenetic mechanisms involved. Pregnant Wistar rats received restraint stress during the last week of gestation. Male offspring were sacrificed on postnatal days 28 and 60. Hippocampus and prefrontal cortex samples were analyzed for gene expression (qPCR for mRNAs and microRNAs), methylation status (bisulfite conversion) and protein levels. Hippocampal neurons in culture were used to analyze microRNA overexpression effects. Prenatal stress induced changes in gpm6a levels in both tissues and at both ages analyzed, indicating a persistent effect. Two CpG islands in the gpm6a gene were identified. Variations in the methylation pattern at three specific CpGs were found in hippocampus, but not in PFC samples from PS offspring. microRNAs predicted to target gpm6a were identified in silico. qPCR measurements showed that PS modified the expression of several microRNAs in both tissues, being microRNA-133b the most significantly altered. Further studies overexpressing this microRNA in neuronal cultures showed a reduction in gmp6a mRNA and protein level. Moreover filopodium density was also reduced, suggesting that GPM6A function was affected. Gestational stress affected gpm6a gene expression in offspring likely through changes in methylation status and in posttranscriptional regulation by microRNAs. Thus, our findings propose gpm6a as a novel target for epigenetic regulation during prenatal stress.

Geomagnetic effects on cosmic ray propagation under different conditions for Buenos Aires and Marambio, Argentina Masías Meza, Jimmy Joel; Dasso, Sergio Ricardo The geomagnetic field (Bgeo) sets a lower cutoff rigidity (Rc) to the entry of cosmic particles to Earth which depends on the geomagnetic activity. From numerical simulations of the trajectory of a proton using different models for Bgeo (performed with the MAGCOS code), we use backtracking to analyze particles arriving at the location of two nodes of the net LAGO (Large Aperture Gamma ray burst Observatory) that will be built in the near future: Buenos Aires and Marambio (Antarctica), Argentina. We determine the asymptotic trajectories and the values of Rc for different incidence directions, for each node. Simulations were done using several models for Bgeo that emulate different geomagnetic conditions. The presented results will help to make analysis of future observations of the flux of cosmic rays done at these two LAGO nodes.

Effect of cultivars and planting date on yield, oil content, and fatty acid profile of flax varieties (Linum usitatissimum L.) Gallardo, Maricel Andrea; Milisich, Héctor José; Drago, Silvina Rosa; González, Rolando José In order to determine the effect of cultivars and planting date on flax fatty acid profile, seed yield, and oil content, an assay with seven cultivars (Baikal, Prointa Lucero, Prointa Ceibal, Panambí INTA, Curundú INTA, Carapé INTA, and Tape INTA) was carried out at Parana Agricultural Experimental Station, Argentina. Significant differences among cultivars were found for content of palmitic (5–7 g/100 g), stearic (5–8 g/100 g), linoleic (13–19 g/100 g), saturated (11–15 g/100 g), and unsaturated acids (92–96 g/100 g) within the seven cultivars. The best seed yields were observed in Prointa Lucero and Carapé INTA varieties (2091.50 kg·ha−1 and 2183.34 kg·ha−1, respectively) in the first planting date and in Carapé INTA and Prointa Lucero (1667 kg·ha−1 and 1886 kg·ha−1, respectively) in the second planting date. A delayed planting date had a negative effect on seed yield (1950 kg·ha−1 and 1516 kg·ha−1) and oil content (845 kg·ha−1 and 644 kg·ha−1) but did not affect oil composition.

A regional audit of nitrogen fluxes in pampean agroecosystems Alvarez, Roberto; Steinbach, Haydée; de Paepe, Josefina Calculations of nitrogen (N) budgets can help in the understanding of agroecosystem functioning and in proposing more sustainable management strategies. Changes in the main N fluxes of the pampean agroecosystems of Argentina were calculated over time. The impact of management changes on regional N budget and possible future trends were estimated. Changes in land use were quantified using national censuses data. Biological N fixation of leguminous forages was assessed using a regression model and local field experimental data. Nitrogen fixation by soybean, the most extensive grain crop, was calculated using an existing model. Fertilizer input was based upon farmer surveys, and atmospheric N input estimated using local data. Nitrogen output by grain harvest was estimated using national yield statistics and averaged grain N concentration derived from many field experiments widespread over the region. During the last 50 years cropped area has doubled as a result of the widespread adoption of soybean as the main component of rotations. The agricultural expansion included areas previously used for grazing on seeded pastures and seasonal graminaceus forages. The historical N budget of the entire region was positive but has dropped from 2.0 Mt y−1 in 1960 to 1.3 Mt y−1 at present. This reduction implies that N fixation by soybean and fertilizer application were lower than the previous livestock/pasture systems N input. During the cropping phase of rotations the N budget was usually negative in the past. Currently, in low yielding areas of semiarid environments, the N budget turned positive; meanwhile in humid climates with high productivity scenarios it remained negative. Fertilizer rates applied balanced N output in the former case but not in the latter. Partial factor productivity of N inputs increased from 3- to 6-fold during the last 50 years in the Pampas. Uncertainties related to the estimations performed are discussed.

Characterization and bacterial adhesion of chitosan-perfluorinatedacid films Bierbrauer, Karina Lilian; Alasino, Roxana Valeria; Muñoz, Adrián; Beltramo, Dante Miguel; Strumia, Miriam Cristina We reported herein the study and characterization of films obtained by casting of chitosan solutions in perfluorinated acids, trifluoroacetic (TFA), perfluoropropionic (PFPA), and perfluorooctanoic (PFOA). The films were characterized by FTIR, solid state 13C NMR, X-ray, AFM, contact angle, thermogravimetric effluent analysis by mass spectrometry, and rheology. The results showed a marked influence of chain length of the perfluorinated acids on the hydrophobic/hydrophilic ratio of the modified chitosan films which was evidenced by the different characteristics observed. The material that showed greater surface stability was chitosan-PFOA. Chitosan film with the addition of PFOA modifier became more hydrophobic, thus water vapor permeability diminished compared to chitosan films alone,this new material also depicted bacterial adhesion which,together with the features already described, proves its potential in applications for bioreactor coating.

Hyperhalophilic archaeal biofilms: growth kinetics, structure and antagonistic interaction in continuous culture Di Meglio, Leonardo Gabriel; Busalmen, Juan Pablo; Pastore, Juan Ignacio; Ballarín, V. L.; Nercessian, Debora Biofilms by the hyperhalophilic archaea Halorubrum sp. and Halobacterium sp. were analyzed, and for the first time the progression of structural features and the developmental parameters of these sessile populations are described. Optical slicing and digital analysis of sequential micrographs showed that their three dimensional structure was microorganism dependent. Biofilms of Halobacterium sp. developed in clusters that covered about 30% of the supporting surface at the interface level and expanded over about 86 ± 4 μm in thickness, while Halorubrum sp. biofilms covered less than 20% of the surface and reached a thickness of 41 ± 1 μm. The kinetics of growth was lower in biofilms, with generation times of 27 ± 1 and 36 ± 2 h for Halobacterium sp. and Halorubrum sp., respectively, as compared to 8.4 ± 0.3 and 14 ± 1 h in planktonic cultures. Differences between microorganisms were also observed at the cell morphology level. The interaction between the two microorganisms was also evaluated, showing that Halobacterium sp. can outcompete already established Halorubrum sp. biofilms by a mechanism that might include the combined action of tunnelling swimmers and antimicrobial compounds.

Effect of a sublethal high-pressure homogenization treatment on the fatty acid membrane composition of probiotic lactobacilli Tabanelli, G.; Patrignani, F; Gardini, F.; Vinderola, Celso Gabriel; Reinheimer, Jorge Alberto; Grazia, L.; Lanciotti, R. High-pressure homogenization (HPH) has been proposed to be applied directly to lactic acid bacterial cells at sublethal levels to enhance some functional properties. As the principal target of HPH are the cell surface envelope structures, the aim of this work was to study the effect of a HPH treatment, applied at 50 MPa, on cell membrane stress responses of alreadyknown functional strains, isolated from Argentinean products. Specifically, the membrane fatty acid composition of cells before and after the sublethal treatment was investigated, and the results showed that plasma membranes, their level of unsaturation and their composition are involved in response mechanisms adopted by microbial cells when subjected to a sublethal HPH stress. In fact, the data obtained demonstrated that the treatment was able to modify the fatty acid profile of the different strains, although a uniform response was not observed. Further studies are necessary both to elucidate the role of each fatty acid in the cell response mechanisms and to clarify the changes in membrane compositions induced by HPH treatment also in relation to the applicative potential of this technique.

Longitudinal study of the species composition and spatio-temporal abundance of Anopheles Larvae in a Malaria risk area in Argentina Dantur Juri, Maria Julia; Galante, Guillermina Begoña; Zaidenberg, Mario; Almiron, Walter Ricardo; Claps, Guillermo Luis; Santana, Mirta Species composition and spatio-temporal abundance of Anopheles (Diptera: Culicidae) larvae and their relationship with environmental variables were studied in an endemic malarious area of northwestern Argentina, where Anopheles pseudopunctipennis is the main vector involved in malaria transmission. From Dec 2001 to Dec 2005, we performed monthly samplings of different aquatic larval habitats, such as puddles, irrigation canals, ponds and pools of Mountain Rivers. To determine the relationship among environmental variables and larval abundance, we used Poisson's regression analysis. We collected 5,079 larvae of which An. pseudopunctipennis was the most abundant species followed by Anopheles argyritarsis and Anopheles evansae. The density of Anopheles pseudopunctipennis larvae fluctuated between the end of spring until autumn, when malaria cases occur in the area. Concurrently, the larval densities of the other anophelinae species fluctuated throughout these climatic seasons. Poisson regression revealed that an increase of mean minimum temperature produced an increase in the abundance of An. pseudopunctipennis and An. argyritarsis. The mean maximum temperature and the water temperature greatly influenced the abundance of An. pseudopunctipennis, An. evansae and An. strodei. Increases of these temperature variables produced increases in abundance of these species. These factors should be taken into consideration when control measures for immature mosquitoes are implemented to reduce the number of larval habitats and the production of larvae, which may ultimately result in the elimination of malaria in this area.; La composición de las especies y la abundancia espacio-temporal de las larvas de Anopheles (Diptera: Culicidae) y su relación con las variables ambientales fueron estudiadas en un área endémica para malaria en el noroeste de Argentina, donde Anopheles pseudopunctipennis es el principal vector involucrado en la transmisión de la enfermedad. Entre diciembre de 2001 y diciembre de 2005 se realizaron muestreos mensuales de diferentes hábitats larvales acuáticos tales como charcos, canales de riego, estanques y ríos de montaña. Para determinar la relación entre las variables ambientales y la abundancia larval, se utilizaron análisis de regresión de Poisson. Se recolectaron 5.079 larvas, de las cuales Anopheles pseudopunctipennis fue la especie más abundante seguida de Anopheles argyritarsis y Anopheles evansae. Las larvas de An. pseudopunctipennis mostraron una fluctuación desde fines de primavera hasta el otoño, cuando los casos de malaria aparecen en el área. Mientras que las otras especies de larvas de anofelinos fluctuaron a lo largo de las estaciones climáticas. Las regresiones de Poisson revelaron que un aumento de la temperatura media mínima produce un incremento en la abundancia de An. pseudopunctipennis y de An. argyritarsis. La temperatura media máxima y la temperatura del agua influenciaron en gran medida la abundancia de An. pseudopunctipennis, An. evansae y An. strodei. Un incremento de estas variables produce un aumento en sus abundancias. Estos factores deben tenerse en cuenta al momento de implementar medidas de control sobre las formas inmaduras de estos mosquitos para reducir el número de hábitats larvales y la producción de larvas, lo cual podría al final resultar en la eliminación de la malaria en esta área.