Recent advances in thermosensitive hydrogels as drug delivery systems: A review Bermudez, Jose Maria; Quinteros, Daniela Alejandra; Grau, Ricardo José Antonio; Allemandi, Daniel Alberto; Palma, Santiago Daniel Polymers that exhibit physicochemical responses to stimuli have been widely explored as potential drug delivery systems. Different kind of stimuli investigated to date includes, for example, chemical substances and changes in temperature, pH and electric fields. Polymers that exhibit dramatic changes in their behavior in an aqueous solution at temperatures close to the body temperature are of particular interest in drug delivery and biomedical applications. Thermosensitive polymers have a wide range of applications, specially, the thermosensitive triblock copolymers because they exhibit unique aqueous solution properties, biodegradability and biocompatibility. These copolymers can be designed to be used as potential drug delivery systems for therapeutic protein drugs or poorly water soluble drugs. This article reviews the applications of polymer solutions with the ability to form in situ implants under temperature changes, in areas of interest to biomedical, pharmacist and engineer scientists. Recent advantages on thermosensitive and biodegradable polymers are discussed to give a wide overview of the available strategies to modify them in order to make them suitable for potential applications in health products.

Coreografías organizacionales: cisnes danzantes en las aguas de la excelencia Napoli, María Laura; Cebey, María Carolina El burn out o „síndrome de quemarse por el trabajo‟ surge a partir de una adicción al trabajo e implica una total devoción y dedicación del tiempo a una meta laboral, provocando consecuencias negativas tanto para el trabajador como para la organización en la cual desempeña su actividad. Desde un marco teórico psico-organizacional, el objetivo de este trabajo consiste en plantear una interpretación de la película Black Swan –El Cisne Negro–, de Darren Aronofsky, tomando como eje de análisis el concepto de burn out. A modo de propuesta metodológica, se presentan y analizan las diferentes fases de evolución del burn out a partir de la puesta en escena planteada en la película. Teniendo en cuenta la relevancia del burn out en las sociedades contemporáneas, se busca convocar la atención de la comunidad profesional de la psicología en general, y de la psicología del trabajo en particular, para la promoción del bienestar psicosocial de los sujetos que desarrollan actividades en organizaciones que persiguen la excelencia.; Burn out syndrome arises from an addiction to work and implies a total devotion and dedication of the time to a labor goal, generating negative consequences for the worker as well as for the organization in he/she carries out their activity. From a psycho-organizational theoretical frame, the objective of this paper is to display an interpretation of the film Black Swan, by Darren Aronofsky, taking the concept of burn out as an analysis axis. As a methodological proposal, the different phases in the evolution of burn out are presented and analyzed in relation to scenes of the film. Considering the relevance of burn out in contemporary societies, the aim is to rise awareness in the professional psychology community un general, and labor psychology in particular, regarding the promotion of the psycho-social well-being of subjects that develop activities in organizations that pursue excellence.

Relevamiento de estudios sobre educación, formación profesional y desarrollo de competencias de jóvenes en América Latina: El caso de México Otero, Analia Este informe sintetiza los resultados arrojados por el relevamiento y sistematización de producciones de conocimiento elaboradas sobre “educación técnica, formación profesional y programas de formación y empleo” para el caso de México, comprendido en el período 2004-2011. La búsqueda re realizó principalmente en revistas académicas, instituciones educativas, artículos o ponencias presentadas en congresos y jornadas, portales estadísticos, etc. El operativo reunió un total de 15 documentos entre los cuales predominaron las producciones de investigación y en menor medida las consultorías y/o evaluaciones. A excepción de un ensayo netamente teórico, los restantes documentos presentan hallazgos sobre investigaciones con trabajos empíricos. La selección incluye un documento producido por la Organización para la Cooperación y el Desarrollo Económico (OCDE), dos consultorías comisionadas por dependencias públicas, una evaluación elaborada por la Secretaría de Educación Pública (SEP) y finalmente un trabajo proyectivo elaborado desde el Gobierno de Nueva León. En el caso de las investigaciones se trata fundamentalmente de estudios de caso, sistematizaciones y un trabajo de carácter documental retrospectivo. La estrategia metodológica utilizada con mayor frecuencia es la cualitativa y el trabajo con fuentes primarias de información. Le siguen aquellas producciones que recurren a la combinación de técnicas cualitativas y cuantitativas. Y por último, trabajos desarrollados desde la perspectiva cuantitativa. Tomando en cuenta el conjunto, se destaca la utilización de dos dispositivos: entrevistas y encuestas.

La batalla por el derecho a la educación en la sociedad neoliberal: Colombia 2011 Gómez Cárdenas, Carlos Wladimir La actual administración del presidente Santos inició un radical proceso de transformación del esquema educativo cuyo vértice aparece en las fuentes de financiamiento futuras de la Educación Superior en Colombia donde claramente el Estado consolida su retirada de la financiación del sistema abriendo paso a inversionistas privados. Objetivos específicos presentados en la reforma tales como : i) promover mayor calidad; ii) generar condiciones para que más colombianos ingresen y se gradúen de la educación superior; iii) ampliar y flexibilizar la oferta de programas; iv) promover el acceso y la permanencia de los estudiantes en el sistema, y v) fortalecer de las fuentes de financiación y la participación regional, esconden verdaderas intenciones de mercantilizar mucho más el sistema educativo por la vía de consolidar cuasimercados.

Colores y surcos: Una propuesta metodológica para el análisis de las representaciones plásticas de la región de Fiambalá (Tinogasta, Catamarca, Argentina); Colors and traces: A methodological approach for analyzing the plastic art representations of Fiambalá region (Tinogasta, Catamarca, Argentina) Basile, Mara Valeria; Ratto, Norma Rosa Se presenta una propuesta metodológica que facilita el manejo y la integración de una muestra compuesta por una gran cantidad de representaciones plasmadas en soportes expresivos de características diferenciadas: piezas cerámicas y bloques rocosos. Se construyen variables analíticas confiables y no ambiguas para dar cuenta de los recursos visuales (caja de herramientas y modos de resolución) utilizados en la realización de las representaciones y así acceder a la interrelación que existe entre gestos, elementos y técnicas utilizadas en la resolución de las imágenes desplegadas en cada uno de los soportes expresivos. El procedimiento propuesto es ejemplificado por medio del análisis de una muestra de 772 representaciones del Período de Desarrollos Regionales o Período Intermedio Tardío (ca. 1200-1400 DC) plasmadas sobre piezas cerámicas y bloques rocosos de la región de Fiambalá.; We introduce a methodological approach that facilitates the handling of large samples of representations found on different supports-ceramic vessels and boulders. Reliable and unambiguous analytical categories are constructed for the visual resources (toolbox and modes of resolution) used to produce the representations, in order to access the interrelation of gestures, elements and techniques used to resolve the images found on each support. Theproposedprocedure is demonstrated through an analysis of a sample of 772 representationsfrom the Regional Development Period or Late Intermediate Period (ca. 1200-1400 AD) found on ceramic vessels and boulders in Fiambalá region.

Depicting borgesian possible worlds Orlando, Eleonora Eva The main purpose of this essay is to show that the philosophical concept of a possible world is part of the Borgesian fiction: in particular, it can be found in the story The Garden of Forking Paths. The main thesis that I will try to defend is the following one: possible worlds are part of the narrative content of the two stories thereby involved, the main one and the novel embedded in it, namely, the book-labyrinth owed to Tsui-Pen; moreover, the concept of a possible world is used in the main story to explain the meaning of the novel. In this sense, it can be taken to play an explanatory role that is similar to the one it plays in semantic theories, and more specifically, in those that appeal to possible worlds in their account of fictional discourse. Finally, the analysis of the use of the possible world concept will enable me to put forward a hypothesis about the conception of the relation between metaphysics and fantastic literature held by Borges.

Reflexiones postcoloniales sobre los cuerpos etnográficos: diálogos con Leenhardt, Merleau-Ponty y Teresa Benítez Citro, Silvia Viviana En el campo de la antropología del cuerpo, el estudio de Leenhardt sobre la representación del cuerpo entre los canacos de Melanesia se convirtió en un trabajo fundacional que contribuyó a enfatizar la confrontación entre las diferentes representaciones del cuerpo humano construidas por las sociedades indígenas y por las modernidades occidentales. Así, las concepciones holistas del vínculo cuerpo-mundo fueron asociadas a las primeras, mientras que la escisión de ese vínculo junto con la idea del cuerpo como "objeto", a las segundas. En este artículo, reviso críticamente este modelo oposicional y sugiero que, a pesar de las diferencias, en estas sociedades también existirían elementos comunes en la experiencia de la relación cuerpo-mundo. Para demostrar esta hipótesis, propongo un diálogo intercultural entre mi etnografía con la gente Toba del Chaco Argentino, y especialmente con las reflexiones de Teresa Benítez, y las filosofías occidentales que confrontaron el dualismo cartesiano, principalmente la fenomenología de Merleau-Ponty. Finalmente, discuto algunas de las consecuencias epistemológicas y políticas de este tipo de perspectivas interculturales para una antropología de y desde los cuerpos en el contexto poscolonial.; In the field of the Anthropology of Body, the Leenhardt's study on the representation of the body among the canacos of Melanesia became a foundational work that contributed to emphasize the confrontation between the different representations of the human body constructed by indigenous societies and the Western modernities. Thus, the holistic representations about the links body-world was associated to the first ones while the split of these links and the idea of the body as "object" were related to the second ones. In this article, I examine this oppositional model and suggest that although the differences in these societies there also are shared elements in the experience of body-world relation. To demonstrate this hypothesis I propose an intercultural dialogue between my ethnography with the Toba people of the Argentine Chaco, and especially with the reflections of Teresa Benitez, and the Western philosophies that confronted the Cartesian dualism, mainly the Phenomenology of Merleau-Ponty. Finally, I discuss some of the epistemological and political consequences of this kind of intercultural perspectives to an anthropology of and from the bodies in the postcolonial context.

Las derechas argentinas en el siglo XX: ensayo sobre su vínculo con la democracia Bohoslavsky, Ernesto Lazaro; Morresi, Sergio Daniel El artículo ofrece un análisis de los vínculos que los partidos de derecha de Argentina tuvieron con el régimen democrático (sea con sus instituciones o con sus fundamentos ideológicos), con laesperanza de desarrollar una caracterización menos esencialista de estos actores. Concretamente, se parte de las siguientes ideas: a) la pluralidad de los actores de derecha, y por lo tanto, de sus proyectos ideológicos; b) la cambiante relación de los actores de derecha con el régimen democrático, al cual en algunos períodos promovían, en otros toleraban y en algunos otros, propugnaban reformar o reemplazar por gobiernos autocráticos; c) la naturaleza de la relación entre las derechas y el régimen democrático parece deberle más a razones de naturaleza táctica que ideológica: es decir, ese vínculo fue más tributario del cálculo que de la doctrina, de la conveniencia momentánea que de definiciones axiológicas permanentes.

La igualdad en espera: el enfoque de género Pautassi, Laura Cecilia Las diversas medidas implementadas en los últimos años en América Latina con el objetivo de garantizar la igualdad entre varones y mujeres han operado sobre un concepto de igualdad meramente formal lo que revela su marcada insuficiencia para alcanzar la igualdad material. La falta de acceso al ejercicio pleno de los derechos de ciudadanía por parte de las mujeres obliga a repensar el funcionamiento de las estructuras de poder asimétricas desde un enfoque de género. El artículo se divide en tres partes: la primera, analiza los principales tratados internacionales que han sido ratificados por la Argentina y que gozan de jerarquía constitucional, analizando el impacto de los mismos en las políticas públicas. La segunda, aborda la interrelación entre el mundo de lo público y de lo privado. Finalmente, se presentan propuestas de políticas públicas tendientes a alcanzar la igualdad material, a partir de la implementación de la transversalización como eje central de las políticas públicas respetuosas de la equidad social y de género.; The diverse measures implemented in Latin America in recent years aimed at guaranteeing equality between men and women have worked on a purely formal concept of equality, revealing its failure to reach material equality. Lack of access to full exercise of citizenship rights on behalf of women forces us to rethink how asymmetric power structures work bearing in mind a gender perspective. This article is structured in three sections: the first analyses the main international treaties ratified by Argentina and which were granted constitutional hierarchy, evaluating their impact on public policies. The second deals with the interrelation between public and private spheres. Finally, the author presents proposals of public policies tending to attain material equality by implementing mainstreaming as a central axis of public policies mindful of social and gender equality.

Condicionantes epistémicos y extraepistémicos de la apropiación social de las creencias científicas; Epistemic and extra-epistemic conditioning of the social appropriation of scientific beliefs Cortassa Amadío, Carina Gabriela En este artículo se examina el proceso de distribución y apropiación social de las creencias científicas como una forma particular de intercambio de conocimiento entre agentes en condiciones de asimetría cognitiva. Se parte de la premisa de que el principio general del testimonio capta la estructura epistémica de deferencia a la autoridad cognitiva que permite la circulación de saber entre científicos y legos. En ese marco se analizan la atribución de crédito y construcción de la confianza recíproca involucrados en el desarrollo de la interacción. Para concluir, se destaca la relevancia que adquiere en esos procesos un núcleo de presupuestos de orden sociocultural -las representaciones sociales de los agentes- que conforma el contexto significativo en que se enmarca el intercambio de conocimiento.; The social distribution and appropriation of scientific beliefs are examined in this paper as a special form of exchanging knowledge among agents in conditions of cognitive asymmetry. The premise that says the “general principle of testimony” seizes the epistemic structure of deference to the cognitive authority enabling the circulation of knowledge among scientists and laymen is the starting point. In this setting credit attribution and the construction of reciprocal trust involved in the development of interaction are analyzed. In conclusion, the relevance attained in such processes of a presumption nucleus of the socio-cultural order –agents’ social representations– is highlighted conforming the significant context where knowledge exchange is framed.

Regional climate variability impacts on the annual grape yield in Mendoza, Argentina Agosta, Eduardo; Canziani, Pablo Osvaldo; Cavagnaro, Martín The Mendoza Province is the major Argentinian vitivinicultural region and its grape production is fundamental for the national vintage. 1979-2009 climate-annual grape yield relationships are analyzed. Total grape yield is shown to depend significantly on regional ´summer´ (October through March) precipitation. Precipitation negatively impacts yields through plant disease and damage/destruction by hail. At interannual scales, ´summer´ regional precipitation variability can explains 25% of the yield variance. Summer precipitation modulates yield with a 6-8 years period: wet (dry) summers can be associated with larger (smaller) grape damage/loss probability during the summer preceding the vintage, as well as lower (higher) grape yields in the subsequent annual campaign due to bud damage. When monthly mean precipitation in Mendoza Observatory is considered wetter Novembers/Decembers can lead to lower yields. Hail during the summer of the previous harvest and during December could lower yields. Winter, late spring and early summer mean maximum temperatures can impact current and subsequent annual yields: warmer (colder) months are linked to enhanced (decreased) yields. These relationships can be associated with circulation and SST conditions in the equatorial and extratropical Pacific basin and southern South America: SSTs within the southeastern South Pacific are related to western equatorial Pacific SSTs and convection, which modify circulation and water vapor transport over southern South America. Statistical multilinear modeling shows that the observed relationships between yield, precipitation and temperature can explain at least 60% of the observed interannual yield variability. It is thus possible to quantitatively estimate, some months in advance, the upcoming vintage´s yield.

The role of the physical structure of Spartina densiflora Brong. in structuring macroinvertebrate assemblages Sueiro, Maria Cruz; Bortolus, Alejandro; Schwindt, Evangelina In Patagonian rocky salt marshes, the presence of the austral cordgrass Spartina densiflora provide habitat for diverse faunal assemblages. Two different mechanisms may influence the distribution and abundance patterns of the associated organisms. Those generated by the biological properties of cordgrasses and those caused or mediated by the physical structure supplied by the plants. The aims of this study were: (1) to determine the effect of cordgrasses on macroinvertebrate assemblages dominating a rocky marsh; and (2) to determine how much of this effect is caused by the physical structure supply by the plants. In order to achieve these objectives we conducted two field manipulative experiments. In the first one we manipulated the presence of defaunated transplants of cordgrass, and in the second one, we did the same with plastic mimics cordgrasses simulating de architecture of Spartina densiflora. In both experiments, sessile and mobile assemblages were separately examined to evaluate whether they respond in the same way or not. Abundance and richness of mobile and sessile organisms were higher in transplant and mimic cordgrass plots compared to controls, indicating that the presence of cordgrasses, either transplanted or artificial, has a positive effect on sessile and mobile assemblages. Furthermore, we found that the composition of mobile and sessile macroinvertebrates assemblages did not differ between transplants and mimics. Therefore, the physical structure of cordgrass was found to be the major factor influencing macroinvertebrates assemblages in the studied Patagonia rocky salt marshes. Within the period of one year, mobile and sessile fauna colonized several times more abundantly transplant and artificial cordgrass than the control plots, highlighting the key role of cordgrasses in optimizing the colonization rate of macroinvertebrate communities in this rocky bottom environment. Since Spartina densiflora is invading different regions worldwide, our study may help to predict its potential effect on the invaded communities.

Biosorption of Trivalent Chromium from Aqueous Solution by Red Seaweed Polysiphonia nigrescens Blanes, Patricia Silvia; Sala, Luis Federico; García, Silvia I.; González, Juan Carlos; Fracaroli, María I.; Harada, Masafumi; Cong, Cong; Niwa, Yasuhiro; Matulewicz, Maria Cristina; Prado, Héctor Juan; Cortadi, Adriana Amalia; Gattuso, Martha This paper presents the biosorption of chromium onto red seaweed (Polysiphonia nigrescens). Batch mode experiments were performed to determine experimental parameters affecting sorption process such as pH, contact time, initial metal ion concentration and biomass dosage. The Cr(III) sorption was dependent on pH and adsorbent dosage. The adsorption kinetic data could be fitted with a pseudo-second-order model and the equilibrium data with a Langmuir model. The maximum sorption capacity was of 16.11 mg/g at pH 4 and 10 g/L of biomass dosage. 0.1 M H2SO4 showed good desorption efficiency (>80%). Spectroscopy analysis showed that Cr(III) sorption on seaweed was mainly through the ion-exchange mechanism. This report indicates that P. nigrescens is an effective and economical sorbent for removal of Cr(III) from wastewaters.

Phase solubility studies and stability of cholesterol/β-cyclodextrin inclusion complexes dos Santos, Cristina; Buera, Maria del Pilar; Mazzobre, Maria Florencia Background: Cyclodextrins (CDs) are able to enhance the solubility, stability and bioavailability of several bioactive hydrophobic compounds by complex formation. They can also be used for removal of undesired components (such as cholesterol, off-flavors or bitter components) present in foods. Although many patents account for the use of cyclodextrins for removal of cholesterol from dairy foods, there is no available information on the effect of water on encapsulation efficiency and on the stability of sterols in CDs. The aim of this work was to study the inclusion properties and the factors affecting the encapsulation and stability of cholesterol in β-cyclodextrin (BCD). The optimum encapsulation conditions (ligand-CD molar ratio, stirring time and temperature), and stability of the complexes as a function of storage time and water content were analyzed. Results: Phase solubility study pointed out the formation of 1:1 stoichiometric complexes between cholesterol and β-cyclodextrin, which was influenced by temperature variations. The process was shown to be exothermic and energetically favored. The presence of cholesterol greatly modified the BCD water sorption curves, being the amount of adsorbed water smaller in the combined systems. The principal 'driving force' for complex formation is the substitution of the high-enthalpy water molecules by an appropriate hydrophobic ligand. The freeze-dried complexes probed to be stable at different storage conditions. Conclusion: The phase solubility and stability data obtained could be essential for selecting the most suitable conditions when CDs are employed either for removing cholesterol or to incorporate functional ingredients (i.e. sitosterol) in the development of innovative food products.

Association of common variants in JAK2 gene with reduced risk of Metabolic Syndrome and related disorders Penas Steinhardt, Alberto; Tellechea, Mariana Lorena; Gomez Rosso, Leonardo Adrián; Brites, Fernando Daniel; Frechtel, Gustavo Daniel; Poskus, Edgardo Background: Disturbances in leptin and insulin signaling pathways are related to obesity and metabolic syndrome (MS) with increased risk of diabetes and cardiovascular disease. Janus kinase 2 (JAK2) is a tyrosine kinase involved in the activation of mechanisms that mediate leptin and insulin actions. We conducted a population cross-sectional study to explore the association between two common variants in JAK2 gene and MS related traits in 724 Argentinean healthy male subjects. Methods A total of 724 unrelated men aged 37.11 ± 10.91 yr were included in a cross-sectional study. Physical examination, anthropometric measurements and biochemical analysis were determined by a standardized protocol. rs7849191 and rs3780378 were genotyped. Analyses were done separately for each SNP and followed up by haplotype analysis. Results rs7849191 and rs3780378 were both associated with reduced risk of MS [p = 0.005; OR (95%CI) = 0.52 (0.33-0.80) and p = 0.006; OR (95% CI) = 0.59 (0.40-0.86) respectively, assuming a dominant model]. rs3780378 T allele was associated with triglyceridemia values under 150 mg/dl [p = 0.007; OR (95%CI) = 0.610 (0.429-0.868)] and TT carriers showed lower triglycerides (p = 0.017), triglycerides/HDL-C ratio (p = 0.022) and lipid accumulation product (p = 0.007) compared to allele C carriers. The two-SNPs-haplotype analysis was consistent with single locus analysis. Conclusions It was found for the first time, significant associations of JAK2 common variants and related haplotypes with reduced risk of MS. These findings could be explained by the role of JAK2 in insulin and/or leptin signaling.

Callochiton monteleonensis n. sp., First record of polyplacophora (Mollusca) from the Neogene of Argentina Urteaga, Diego Gaston; Griffin, Miguel; Pastorino, Roberto Santiago Guido A new species of chiton is described from early Miocene deposits of the Monte Len Formation, in Santa Cruz Province, Argentina. Callochiton monteleonensis n. sp. clearly differs from known fossil and Recent species of the southwestern Atlantic because the central area of its intermediate valves has a stepped appearance, in which each step is marked by a longitudinal rib. It is similar to Callochiton kapitiensis Mestayer, 1926, a Recent species from New Zealand. Biogeographic implications are discussed. This is the first record of a polyplacophoran from Neogene deposits of Argentina.

Lo agonal y lo irenéico en la filosofía Blanco Ilari, Juan Ignacio La esencia de lo que debemos entender por filosofía se encuentra más del lado del quehacer, de la tarea, que del lado de “lo hecho”. Entre el sustantivo (filosofía) y el verbo (filosofar) hay una estrecha relación. Este trabajo se aboca, primeramente, a lo que está antes del quehacer, que se encuentra en la experiencia de ruptura. Luego se propone articular las dos grandes actitudes originarias que se abren a partir de ese momento, una más combativa (lo agonal) y la otra más pacifista (lo ireneico).; A essência do que devemos entender por filosofía é mais próxima à tarefa que ao “jáfeito”. O substantivo (filosofía) e o verbo (filosofar) estão íntimamente relacionados. Este trabalho é abocado, en primeiro lugar, para o que está diante da tarefa, que acontece na experiência de ruptura. Depóis, ele se propõe articular as duas grandes actitudes originárias que se oferecem depóis desse momento, uma mais combativa (o agonal) e a outra mais pacifista (o irênico).

Coping between crises: Early Triassic-early Jurassic bivalve diversity dynamics Ros, Sonia; De Renzi, Miquel; Damborenea, Susana Ester; Márquez Aliaga, Ana The Triassic is bounded by two of the most severe biotic crises, but nevertheless this time was, for bivalves, both a recovery and a diversification period, and a moment to fully exploit some of their evolutionary novelties. Just how and when this was achieved is analyzed in this paper, which covers Induan to Sinemurian bivalve diversity, based on a newly compiled database. Taxonomic diversity and ecospace dynamics are examined separately. Diversity and evolutionary rates were assessed, extinction selectivity was tested using a resampling algorithm, and cohort analysis was used to study extinction patterns. During the Early Triassic most bivalve genera were survivors from the Permian and they were mainly cosmopolitan epifaunal and semi-infaunal endobyssate taxa. Reclined, epifaunal and semi-infaunal bivalves increased in diversity during the Triassic, but from Norian on, their diversity declined, and they were strongly affected by the T/J crisis. Although the Triassic/Jurassic extinction strongly impacted bivalve taxonomic diversity, it had little impact on bivalve ecologic diversity. Not a single bivalve life strategy was eliminated at the end of the Triassic. The present study does not support previous conclusions that infaunal bivalves suffered greater extinction than epifaunal ones during the T/J extinction. Not all life strategies were equally affected by the extinction event, being the deep infaunal burrowers positively selected. Bivalves with major energetic requirements seem to have been more affected with negative selectivity on fast shallow burrowers. The ecologic diversity changes of bivalves during the Late Triassic and several adaptations of durophagous predators reflect the effects of increasing predation pressure and support a Late Triassic origin of the Mesozoic Marine Revolution.

Auxotrophic mutant of Staphylococcus aureus interferes with nasal colonization by the wild type Barbagelata, María Sol; Álvarez, Lucía; Gordiola, Mariana Laura; Tuchscherr, Lorena Paola Nelly; von Eiff, Cristoff; Becker, Karsten; Sordelli, Daniel Oscar; Buzzola, Fernanda Roxana Staphylococcus aureus nasal carriage is a risk factor for infection in humans, particularly in the hospital setting. Bacterial interference was used as an alternative strategy for the prevention of upper respiratory, urogenital and gastrointestinal tract infections. This study was designed to assess if the administration of a live-attenuated aroA mutant of S. aureus is useful as a potential approach to prevent transient staphylococcal nasal carriage by virulent strains. We constructed an aroA mutant of S. aureus Newman strain by homologous recombination. The auxotrophic NK41 mutant was attenuated as determined by the increase of the LD50 after intraperitoneal challenge. In mice, previous nasal colonization with the NK41 mutant significantly reduced the number of CFU of S. aureus (HU-71 and Hde288) clinical isolates and the parental Newman strain. The NK41 mutant was unable to induce a pro-inflammatory response and to damage the invaded human respiratory epithelial cells. Moreover, the cells previously or simultaneously infected with the NK41 mutant were invaded by virulent strains in a significantly lower degree than those of the control group. In conclusion, the attenuated NK41 mutant interfered with the colonization and establishment of pathogenic strains of S. aureus, which produce severe infections. © 2011 Institut Pasteur.

Repensando la arqueología de Santiago del Estero: Construcción y análisis de una problemática Taboada, Constanza Este trabajo repiensa algunos aspectos de la arqueología santiagueña y plantea una definición problemática para el estudio de los procesos prehispánicos ocurridos en el territorio. Para ello analiza e interrelaciona dos aspectos: las circunstancias históricas que han dado lugar a la percepción, gestión e investigación de una "arqueología santiagueña", y los avances en la generación y análisis de datos y planteo de hipótesis sobre la región realizados por el proyecto de investigación. Sobre la base de ello y de ejemplos de análisis, plantea una lectura global y de síntesis de algunas de sus problemáticas.; This article rethinks some aspects of Santiagueña archaeology and proposes a critical definition for the study of prehispanic processes that occured in the region. In this aim two interrelatedthemes will be analysed: the historical circumstances that have given place to the perception,practice and investigation of a “Santiagueña archaeology”, and the results of the uncoveringand analysis of data concommitant with the hypothesis concerning the region proposed by our investigation project. Working on this basis and on examples from these analysis, we present a global revision and synthesis of some of the Santiagueña’s archaeologcial polemics.