Los conglomerados sintectónicos de la formación las cumbres (Plio-Pleistoceno), sierras pampeanas de La Rioja y Catamarca, Argentina.; Stratigraphy and tectonic inversión of the Neogene rift in Campo del Arenal, Catamarca, NW Argentina Bossi, Gerardo Eugenio; Georgieff, Sergio Miguel; Muruaga, Claudia Marcela; Ibañez, Lucía Marina; Sanagua, Javier G. La Formación Las Cumbres (Plio-Pleistoceno) aflora extensamente en el área comprendida entre lassierras de Velasco y Paimán al sur y las sierras de Vinquis y Zapata al norte (Provi ncias de Catamarca y La Rioja, NO Argentina) cubriendo concordantemente la Formación Salicas (Mioceno tardío-Plioceno temprano). La Formación Las Cumbres es una sucesión granocreciente de conglomerados y areniscas que desarrollan una gran bajada aluvial formada durante el pico del levantamiento de las Sierras Pampeanas. En el sector sureste del área estudiada (las Cumbres de los Pozuelos), la falla transpresiva Uscamayo creó cuatro alounidades locales separadas por discordancias angulares (progresivas), en el bloque hundido. Cada alounidad constituye un estadio de actividad tectónica intensa, mientras que las discordancias representan etapas intermedias de intensa erosión y pedimentación. Se han distinguido dos facies sedimentarias principales: 1. conglomerados de milonitas angulosas y granitos deformados que dominan la parte sur del sistema de dispersión y 2. conglomerados polimícticos redondeados (granitos, esquistos, volcanitas, metavolcanitas y milonitas) que corresponden al sector norte. Las facies 1 provienen de las sierras de Velasco, cerro La Punta y Paimán, mientras que las facies 2 derivan del conjunto de sierras integradas por Vinquis, Zapata, Copacabana y Cerro Negro. Los dos sistemas convergen hacia el área de las Cumbres de los Pozuelos para hundirse allí en el 'Bolsón de Pipanaco'. Estos sistemas de dispersión no son congruentes con la posición actual de las sierras que han sufrido desplazamientos importantes en sentido norte-sur durante la etapa más intensa de levantamiento, ocurrida en el Pleistoceno temprano y 'medio'; The Santa María-Hualfín Basin in the NW Pampean Ranges started during the extensional faulting of a large NNW-SSE elongated dome, developed abo ve a peneplained basement. The faulted blocks were tilted outwards from the axis of the dome. Subsequently, the Neogene sedimentation (Santa María Group) was concentrated along listric faults bounding hemigrabens, reaching up to 3,000 m thick in these áreas. An intrabasin volcanic event occured during 11-6 Ma and was associated to asthenospheric upwelling and crustal thickening. A change from extensional to compressive tectonism, represented by the Intra-Aldalhuala disconformity, occurred at 4.8-5.2 Ma, resulting in approximately 9% shortening. Subsequently, during Pliocene times, thermal subsidence took place.

El sistema lacustre de la Formación Mollar en el depocentro triásico de Santa Clara (provincia de Mendoza, Argentina); The lacustrine system of the Mollar Formation in the Triassic Santa Clara Depocenter (Mendoza Province, Argentina) Spalletti, Luis Antonio; Zavattieri, Ana Maria El depocentro triásico de Santa Clara, Cuenca Cuyana, se caracteriza por espesos depósitos generados en ambiente lacustre. Uno de ellos, con un registro de más de 345 m, corresponde a la Formación Mollar. El tramo inferior a medio está caracterizado por una monótona sucesión de lutitas bituminosas acumuladas por decantación suspensiva en el ?offshore? anóxico de un cuerpo lacustre hidrológicamente cerrado y que muestra alto contenido de materia orgánica amorfa de origen algal y de restos de plantas terrestres muy degradadas junto a sulfuros de hierro autígenos. Intercalan

areniscas finas debidas a corrientes de turbidez diluidas y carbonatos estromatolíticos. En esta sucesión se definen ciclos granocrecientes de pequeña escala (PACs) que se atribuyen a episodios de expansión-retracción lacustre controlados por cambios climáticos. Asociaciones de facies heterolíticas representan los depósitos de la transición entre los ambientes de ?nearshore? y ?offshore? lacustre. La sección superior de la Formación Mollar se compone de sucesiones políticas con profusa bioturbación que sugieren mayor oxigenación del sustrato y se asignan a ambiente de costa afuera de un sistema lacustre holomíctico hidrológicamente abierto. Intercalan areniscas producto de flujos hiperpicnales. Depósitos de areniscas con abundantes trazas fósiles y estructuras de olas y flujos unidireccionales, representan a sectores marginales del ambiente lacustre. Además de los ciclos de alta frecuencia, en la Formación Mollar se definen tres secuencias asimétricas de mayor escala atribuidas a episodios mayores de expansión-contracción lacustre debidos a la interacción entre factores climáticos y tectónicos. El diseño de superposición granocreciente de la Formación Mollar y la gradual transición a depósitos fluviales de la sobreyacente Formación Montaña refleja asimismo una constante reducción del espacio de acomodación sedimentaria en el depocentro de Santa Clara a medida que se produjo la acumulación de los depósitos estudiados.; The Triassic Santa Clara depocenter, Cuyo Basin, is characterised by thick fine-grained deposits formed in lacustrine systems. One of them, represented by the Mollar Formation, exceeds the 345 m. The lower to middle section of this unit is dominated by a monotonous succession of black shales having a high content of amorphous organic matter produced by algae and highly degraded plant remains. These deposits were formed by suspension fallout in the anoxic ‘offshore’ sector of a hydrologically closed lake. Thin and fine-grained turbiditic beds and stromatolitic carbonates are intercalated in the fine-grained succession. Small-scale coarsening-upward cycles (PACs) are attributed to episodes of lake expansion-retraction driven by climate change. A facies association composed of an heterolithic package represents the deposits of the transition between ‘nearshore’ and ‘offshore’ settings. The upper section of the Mollar Formation essentially consists of bioturbated mudstones suggesting a greater oxygenation of the substrate. They are assigned to the ‘offshore’ environment of a holomictic hydrologically open lake system. Sporadic hyperpycnal flows are documented by intercalations of sandy turbidites. Bioturbated sandstone beds with primary structures indicative of both normal and storm wave action and unidirectional flows, represent the marginal deposits of the lacustrine system. In addition to the high-frequency cycles, three larger scale asymmetrical sequences are identified in the Mollar Formation. These sequences suggest episodes of major expansion-contraction of the lake system due to the interaction between climatic and tectonic factors. The overall shallowing up stacking pattern of the Mollar Formation and the gradual transition to fluvial deposits of the overlying Montaña Formation reflects a steady reduction of accommodation space in the Santa Clara depocenter during the accumulation of the studied succession

El desarrollo de la escritura de palabras en español: Interacción entre el conocimiento fonológico y ortográfico; Spelling development in Spanish: Interaction between phonological and orthographic knowledge Sanchez Abchi, Veronica Soledad; Diuk, Beatriz Graciela; Borzone, Ana Maria; Ferroni, Marina Valeria Este trabajo se propone ampliar los conocimientos acerca de las estrategias que utilizan los niños en la tarea de escritura de palabras en español. Para ello se analizó, en dos experimentos, de qué manera incidían las variables de complejidad, extensión y frecuencia de las palabras en la escritura al dictado. Asimismo, se analizó la interacción entre las variables fonológicas y el conocimiento ortográfico en el aprendizaje temprano de la escritura. Se aplicaron pruebas de escritura de palabras a 59 niños al finalizar el primer año y nuevamente al terminar el segundo año de la EGB. Los resultados mostraron que los mecanismos fonológicos son fundamentales en la primera etapa de aprendizaje de la escritura. Al finalizar el 2do año escolar se observó también una interacción entre los mecanismos fonológicos y léxicos.; This study analyzed the acquisition of word spelling strategies in Spanish-speaking children, during the first two years of elementary education. The cognitive word spelling models, initially developed for English, describe different stages in the acquisition spelling process. In the first stage, children write by memory, reproducing visual cues. At a second stage, children analyze the phonological structure of the word. Finally, in an orthographic stage, children can write words, using lexical information, without phonological mediation (Frith, 1984, 1985; Marsh, Friedman, Welch & Desberg, 1980). Even when the stages theory was discussed, these first studies allowed the identification of early lexical strategies and phonological mechanisms implied in the English word spelling processes. However, English is a language with a deep orthography, and the phonological strategy is a necessary mechanism but it is not enough to spell words properly. On the contrary, the Spanish orthographic system is shallow, and the phonemes-graphemes correspondences are very regular. Consequently, the spelling strategies could be different in these two languages, and the models developed for English would partially explain the orthographic learning process in transparent languages. This work aims to contribute to the knowledge on early spelling word strategies in Spanish. In two experiments, first and second grade children were given spelling tests designed to explore their phonological and orthographic knowledge. In the first experiment, the incidence of word complexity, length and frequency on spelling performance was explored. However, there was a possibility that, if children performed better in frequent words spelling, in relation to less frequent, they were resorting to their lexical knowledge. In this case, children were using an orthographic-lexical strategy. On the other hand, the possibility of writing complex and long words is associated to the phonological awareness level and correspondence knowledge. If children were able to easily write frequent and non frequent short and simple words, but had difficulties in writing long and complex words, they were possibly analyzing the sounds of the words and thus activating the corresponding letters. If the word was long or complex and the phonological skills were not well developed, children would have difficulties in writing them; one such problem, for example, would be in omitting letters. In this case, complexity and length variables that show the use of an analytic strategy would be influencing the performance. In the first experiment, the orthographic variable was not considered specifically, so a second experiment was designed. The second experiment evaluated orthographic knowledge, considering the orthographic characteristics of the words. The acquisition of the consistent and inconsistent correspondences was compared. The consistent correspondences could be solved using transcription rules, while inconsistent correspondences could be written only through lexical knowledge. Furthermore, consistent correspondences could be independent or dependent from context. In the first case, we refer to phonemes that are always represented with the same letter. In the other case, transcription depends on the syllabic context. Tests were applied at the end of the first and the second year of primary education. Results of the first experiment showed that, at the end of the first year, there was no frequency effect but the variables of complexity and length affected the children's performance. At the end of the second year, a frequency effect and a significant interaction between complexity and frequency were found. In the second experiment, a significant consistence effect was observed, but there was no frequency effect. These results indicate that phonological strategies are fundamental in the beginning of spelling acquisition. On the contrary, lexical mechanisms appear later and they are acquired gradually. Indeed, at the end of the first grade, frequency only affected performance of context dependent correspondences, but not independent. Likewise, interaction between phonological and lexical strategies was found only at the end of the second year. Pedagogical implications were also considered.

Mechanical characterization of nano-reinforced silica based sol-gel hybrid coatings on AISI 316L stainless steel using nanoindentation techniques Ballarre, Josefina; Jimenez Pique, Emilio; Anglada, Marc; Pellice, Sergio Antonio; Cavalieri, Ana Lia One way to enhance the surface properties of metals used as surgical implants such as wear or protective behaviour is to use hybrid organic-inorganic sol-gel coatings. The addition of SiO2 colloidal particles to some hybrid formulation is thought to give films with bigger thickness than the coatings without particles, acting as mechanical reinforcement and to make an adequate surface to resist the extreme surgical procedures taking place in orthopaedic replacements. Coatings made by sol-gel with tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) with the addition of silica nanoparticles were applied onto surgical grade stainless steel. One of the most recent techniques used to study the mechanical properties of thin films is the instrumented indentation, known as nanoindentation, was used to evaluate elastic modulus, hardness and friction coefficient. This is a superficial technique used to measure quasi-statically the penetration of an indenter at increasing loads applied to very little volumes of material. The mechanical properties values found for the TEOS-MTES-10%SiO2 coating are smaller than for the 30% filled coating, and higher that the coating without nanoparticles. In the scratch test of the TEOS-MTES-SiO2 30 wt.% coating it can be seen that in this case the failure takes place at higher applied load than for the less silica reinforced one, indicating a much better adhesion than the system with 10% of SiO2 nanoparticles. © 2009 Elsevier B.V. All rights reserved.

BiHEA: A hybrid evolutionary approach for microarray biclustering Gallo, Cristian Andrés; Carballido, Jessica Andrea; Ponzoni, Ignacio In this paper a new hybrid approach that integrates an evolutionary algorithm with local search for microarray biclustering is presented. The novelty of this proposal is constituted by the incorporation of two mechanisms: the first one avoids loss of good solutions through generations and overcomes the high degree of overlap in the final population; and the other one preserves an adequate level of genotypic diversity. The performance of the memetic strategy was compared with the results of several salient biclustering algorithms over synthetic data with different overlap degrees and noise levels. In this regard, our proposal achieves results that outperform the ones obtained by the referential methods. Finally, a study on real data was performed in order to demonstrate the biological relevance of the results of our approach. © 2009 Springer Berlin Heidelberg.

Coke analysis by temperature-programmed oxidation: Morphology characterization Sanchez, Barbara Sabrina; Gross, Martin Sebastian; Dalla Costa, Bruno Oscar; Querini, Carlos Alberto Temperature-programmed oxidation (TPO) profiles obtained using high final temperature are usually very similar in shape and it is not possible to easily distinguish among different kinetic models. Typically, statistical criteria are used to select the one that best fits the experimental TPO profile. In this work, we show that using final temperatures selected in such a way that the coke is still reacting with oxygen, relevant information can be obtained from the experimental profile. Coked naphtha reforming catalysts, obtained from an industrial reactor, are characterized by running TPO analyses using intermediate temperatures. Results clearly show that the coke reaction order changes as the coke conversion increases. When the initial coke content is approximately 5 wt% or higher, coke has a tridimensional structure that leads to a low reaction order, close to 0.2. At high conversion levels, approximately 80%, the coke reaction order starts increasing until reaching a value of 1 at conversion close to 1. This information is easily obtained by plotting the experimental coke reaction order using the data at constant temperature. In this way, it is possible to easily distinguish among different models, and to replicate the experimental results.

Conformational and vibrational analysis of methyl methanesulfonate, CH3SO2OCH3 Tuttolomondo, María Eugenia; Navarro, Amparo; Peña, Tomás; Varetti, Eduardo Lelio; Parker, Stewart F.; Ben Altabef, Aída The molecular structure of methyl methanesulfonate, CH3SO 2OCH3, has been optimized by using methods based on density functional theory, coupled cluster, and Moller-Plesset second order perturbation theory (MP2). With regard to CH3SO2OCH 3, two populated conformations with symmetries Cs and C1 are obtained, the former being more stable than the latter. The theoretical data indicate that although both anti and gauche conformers are possible by rotation about the S-O bond, the preferred conformation is anti. The total energy as a function of the CSOC dihedral angle has been calculated using the MP2 method with the 6-31G(d) and cc-pVDZ basis sets and the hybrid functional B3LYP using 6-31G(d), 6-311G(d,p), and 6-311++G(d,p) basis sets. A natural bond orbital analysis showed that the lone pair →σ * hyperconjugative interactions favor the anti conformation. Furthermore, the infrared spectra for the liquid and solid phases, the Raman spectrum for the liquid one, and the inelastic neutron scattering spectrum of the solid phase have been recorded, and the observed bands have been assigned to the vibrational modes. The experimental vibrational data, along with calculated theoretical force constants, were used to define a scaled quantum mechanical force field for the target system that enabled us to fit the measured frequencies with a final root-mean-square deviation of 10 cm-1.

(1,1-Dichloro-2,2,2-trifluoroethylimino)sulfur dichloride, CF3CCl2N=SCl2: Vibrational spectra and quantum chemical calculations Flores Antognini, Andrea; Cutin, Edgardo Hugo; Robles, Norma Lis; Oberhammer, Heinz The vibrational spectra of (1,1-dichloro-2,2,2- trifluoroethylimino)sulfur dichloride, CF3CCl2N@SCl2, were recorded in the gas phase with IR spectroscopy and in the liquid state with Raman spectroscopy. Quantum chemical calculations at the HF, B3LYP (6-311+G(d) and 6-311+G(2df) basis sets) and MP2 levels of theory (6-31+G(d) and 6-311+G(df) basis sets) were performed. According to all calculations the lowest energy conformer possesses C1 symmetry with syn orientation of the SCl2 group relative to the N-C bondand near-trans orientation of the CF3 group relative to the N=S bond. Calculations predict the presence of a second stable conformer with anticlinal orientation of the SCl2 group which, however, possesses considerably higher energy and is therefore not observed in the analysis of the experimental vibrational spectra. The vibrational spectra were assigned for a single conformer in accordance with these calculations.

Alternate Cu2 and Er2 spin carriers in a carboxylate bridged chain: EPR study Calvo, Rafael; Rapp, Raul E.; Sartoris, Rosana Patricia; Santana, Ricardo C.; Perec, Mireille We report powder EPR measurements at 9.48 GHz and temperatures of 4 K e T e 30 K and at 33.86 GHz and T = 300 K for the polymeric compound {[Cu2Er2(L)10(H2O)4] ·3H2O}n (HL ) trans-2-butenoic acid) having alternate Cu2 and Er2 dinuclear units bridged by carboxylates along a chain. Above 70 K, when the ErIII resonance is unobservable and uncoupled from the CuII ions, the spectrum arises from the excited triplet state of antiferromagnetic Cu2 units, decreasing in intensity as T decreases, and disappearing when these units condensate into the singlet ground state. Fit of a model to the spectra at 9.48 and 33.86 GHz and 300 K gives gCu//= 2.379, gCuper = 2.065, DCu= -0.340 cm-1, and ECu ∼ 0 for the g-factors and zero field splitting parameters. From the T dependence of the intensity of the spectrum above 70 K, we obtain JCu-Cu = -336(11) cm-1 for the intradinuclear exchange interaction. Below 50 K, a spectrum attributed to Er2 units appears, narrows, and resolves as T decreases, due to the increase of the spin-lattice relaxation time T1. The spectrum at 4 K allows calculating g values g1=1.489, g2= 2.163, and g3= 5.587 and zero field splitting parameters DEr=-0.237 cm-1 and EEr = 0.020 cm-1. The results are discussed in terms of the properties of the Cu and Er ions, and the crystal structure of the compound.

Crecimiento y caracterización de películas delgadas de tio2 y ti1- xfexo2 Galvis, J.; Ramirez Jimenez, Helena; Montes, J.; Sanchez, L.; Beltran, J.; Barrero, C.; Morales, A.; Gomez, J.; Tirado Mejia, L.; Osorio, J. Titanium dioxide (TiO2) and Fe-doped titanium dioxide (Ti1-xFexO2) thin films were grown on silicon substrates using the magnetron sputtering Rf (13.56 MHz) technique. The relevant growth parameters for the samples (pressure, power, gas mixture ratio, distance between target-substrate, among others) were found. The plasma deposition environment for the ternary films was characterized by optical emission spectroscopy in order to verify and identify the present species which were iron and titanium. The TiO2 films, deposited on silicon substrates [100], showed an amorphous phase while the ternary films showed low crystallinity. After annealing at 800 °C crystalline phases appeared, rutile in binary films and mixed in ternary films.

Differential cholinoceptor modulation of nitric oxide isoforms in experimentally-induced inflammation of dental pulp tissue de Couto Pita, Alejandra Karina; Passafaro, D.; Ganzinelli, Sabrina Belen; Borda, Enri Santiago; Borda, Enri Santiago Aim The aim of the study was to investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of endothelial (e), neuronal (n) and inducible (i) nitric oxide synthase (NOS) activity and expression in experimentally induced inflammation of rat dental pulp tissue. Methodology Inflammation was induced by application of bacterial lipopolysaccharide (LPS) to the pulp. Extirpated pulp-tissue samples were incubated in saline solution until the various experiments were performed. Saline-treated pulp and healthy pulp tissues were used as controls. NOS activity was measured by the production of [U-14C]-citrulline from [U-14C]-arginine. Nitrite/nitrate assay was evaluated by the conversion of nitrate to nitrite in the presence of nicotinamide adenine dinucleotide phosphate. i-nos, e-nos and n-nos mRNA levels were measured using reversetranscriptase polymerase chain reaction by co-amplification of target cDNA with a single set of primers. Results Application of LPS to the pulp increased NOS activity and nitrate production (P < 0.001), generated by iNOS over-activity and expression. Pilocarpine acting on mAChRs triggered a biphasic action on NOS activity and NO accumulation. At low concentrations, pilocarpine induced a negative effect associated with a decrease in i-nos mRNA level, whilst at high concentration, it produced a positive effect associated with increased e-nos and n-nos mRNA levels. In control pulp tissue, only the positive effect of pilocarpine was observed. Conclusions Irreversible pulpitis changes mAChR conformation increasing its efficiency of coupling to transducing molecules that in turn induce activate iNOS. The capacity of pilocarpine to prevent NO accumulation and iNOS activity, by acting on mAChR mutation induced by pulpitis, might be useful therapeutically as a local treatment.

The K-theory of toric varieties Cortiñas, Guillermo Horacio; Haesemeyer, C.; Walker, M. E.; Weibel, C. Recent advances in computational techniques for K-theory allow us to describe the K-theory of toric varieties in terms of the K-theory of fields and simple cohomological data.

Familia y Heteronormatividad Guerra, Luciana Analía Desde diferentes disciplinas y perspectivas es estudiada una institución tan compleja y dinámica como la familia. Abordajes estadísticos, antropológicos, sociológicos, históricos, intentan comprender y analizar la diversidad de estructuras familiares. Incluso, estos estudios, cambiaron la noción de “familia” por el de “organizaciones familiares” para evitar caer en definiciones ahistóricas y monolíticas que pretenden instalar como “natural” una única manera de agrupamiento familiar. Sin embargo, la feminista marxista Heidi Hartmann, considera que estas investigaciones históricas, sociológicas y antropológicas, abordan las organizaciones familiares como unidades cuyos miembros comparten intereses, minimizando la conflictividad que pueda darse entre los mismos. Este punto de partida teórico no es favorable para visibilizar y comprender la situación concreta de las mujeres en el seno familiar. A partir de los aportes de los Estudios de Género y de la teoría feminista, la familia va a ser cuestionada y denunciada como ámbito de dominación masculina por excelencia dónde el mandato patriarcal de ser madre opera como eje organizador de la vida de las mujeres. Las relaciones de poder, las jerarquías por edad y sexo, la Heterosexualidad Obligatoria, la división sexual del trabajo, el trabajo doméstico no remunerado, la transmisión de valores patriarcales, la producción del binarismo sexual y la reproducción de los estereotipos de género en el proceso de socialización, son algunas de las categorías producidas por la teoría feminista para visibilizar los mecanismos de subordinación de las mujeres. Lejos de considerar a la familia como una unidad armónica con intereses comunes, esta perspectiva pone de manifiesto los conflictos y las tensiones existentes en la misma. Teniendo en cuenta los cambios económicos y políticos de los últimos tiempos y el impacto que los mismos han tenido en la estructuración de las familias, intentaré analizar, en qué medida, la familia continúa siendo o no una institución medular del sistema patriarcal, reproductora del orden heteronormativo. Con esto, nos referimos a un orden construido a partir de un sistema sexual binario y jerárquico: mujeres / femeninas / inferiores y varones / masculinos / superiores, reforzado, a su vez, por la esencialización de la sexualidad a través de la imposición de la Heterosexualidad Obligatoria. En definitiva, este sistema sexo-género como lo denominó Gayle Rubin, no sólo limita la definición de lo humano a dos categorías genéricas, varones y mujeres, sino que también disciplina el deseo sexual para que los sexos opuestos se atraigan mutuamente. Resulta de suma importancia para nuestro análisis, señalar que la heteronormatividad del patriarcado conduce a la discriminación e inferiorización tanto de toda orientación sexual disidente, como de cualquier identidad genérica que no respete la dicotomía varón-mujer –léase: travestis, transexuales, intersexuales, transgéneros, lesbianas, bisexuales, gays. Un recorrido por la realidad cotidiana de éstos colectivos humanos, nos permitirá analizar en qué sentido la “crisis de la familia” de la que tanto se habla tiene que ver con una apertura ideológica respetuosa de las múltiples maneras de vivir, construir y habitar las comunidades denominadas familias, o responde al alarmismo nostálgico de mentes conservadoras que perderían muchos privilegios si la “familia tradicional” deja de ser modelo y ejemplo de vida para las futuras generaciones.

El registro biológico humano de la costa meridional de Santa Cruz Suby, Jorge Alejandro; Guichon, Ricardo Anibal; Zangrando, Atilio Francisco Javier La costa patagónica constituye un sector de riesgo para el registro arqueológico, asociado a factores naturales y antrópicos. Al mismo tiempo, la conservación de las colecciones bioarqueológicas, destacándose la pérdida de restos óseos e información asociada por escasez de recursos, desconocimiento o falta de atención especializada, representa escenarios de riesgo para el registro. Una de las áreas para las cuales no se dispone hasta el momento de información bioarqueológica es la región que comprende la costa meridional de la provincia de Santa Cruz. Considerando esta ausencia de información, el objetivo de este trabajo es presentar y discutir los primeros resultados sobre restos óseos humanos hallados en la región costera próxima a la desembocadura del Rio Santa Cruz (Santa Cruz, Argentina). Los estudios incluyen el análisis de las situaciones de hallazgo y riesgo de los restos recuperados en acciones de rescate, el reconocimiento y puesta en valor de materiales depositados en el Museo Regional Carlos Borgialli (Puerto Santa Cruz, Santa Cruz, Argentina) y estudios paleopatológicos. Al mismo tiempo se informan y analizan resultados cronológicos e isotópicos. Los resultados brindan evidencias claras de la ocupación de la región costera al menos durante los últimos 2000 años, consumo de recursos predominantemente terrestres y un estilo de vida que favorece el desarrollo de lesiones articulares con escasos indicios de stress sistémico que coinciden con los resultados reportados para la región continental del estrecho de Magallanes.

Hydrosilylation of C-C multiple bonds using (Me3Si) 3SiH in water: Comparative study of the radical initiation step Postigo, Jose Alberto; Kopsov, Sergey; Zlotsky, Simon S.; Ferreri, Carla; Chatgilialoglu, Chryssostomos The classical radical-based hydrosilylation reaction of organic compounds bearing C-C multiple bonds is usually carried out in organic solvents and is herein presented in water with both organic solventsoluble and water-soluble substrates. Different initiation methods to accomplish the radical-induced hydrosilylation reaction of C-C multiple bonds in water with (Me 3Si)3SiH are presented. In the thermal decomposition of azo compounds, the system comprising substrate, silane, and azo-initiator (ACCN) mixed in aqueous medium at 100 °C worked well for both hydrophilic and hydrophobic substrates, with the only variation that the amphiphilic thiol HOCH2CH3SH was also needed in the case of the watersoluble compounds. Dioxygen initiation is shown to afford excellent yields of hydrosilylated products derived from substrates bearing C-C triple bonds and moderate to low yields of hydrosilylated products derived from C-C double-bonded compounds in water. Photochemical initiation in the absence of a chemical radical precursor other than the silane is also found to be a very efficient and convenient method to induce the hydrosilylation reaction of both C-C double and triple bonds of organic compounds (hydrophilic and hydrophobic substrates) with (Me3Si)3SiH in water. These three alternative radicalbased methodologies studied in water are confronted.

Feeding behavior of Adelomelon ancilla (Ligfoot, 1786): A predatory neogastropod (Gastropoda: Volutidae) in Patagonian benthic communities Bigatti, Gregorio; Sanchez Antelo, Carlos; Miloslavich, Patricia; Penchaszadeh, Pablo Enrique Adelomelon ancilla, a volutid commonly found in shallow water in northern Patagonia, is a top predator in the benthic communities of this region. This species presents an anemone (Antholoba achates) epibiosis that may protect it from predators. Adelomelon ancilla captures prey by tightly engulfing it with the foot, and ingests them, generally alive, after narcotizing their muscles. A narcotizing substance, produced by the accessory salivary glands, is released through the proboscis into the prey while the latter is tightly enveloped within the foot, allowing for prey narcotization. In this space, water is not abundant and, therefore, the salivary secretion reaches a high concentration, with a pH of around 10. Analysis of prey obtained in situ indicated that A. ancilla mainly consumes bivalves (88.9%), gastropods (9.5%) and, rarely, sea urchins (1.6%). Ingestion of the prey usually occurs while the predator is buried in the substrate, and may last for several hours. The anatomy of the alimentary system and the pH of various organs involved in prey capture and digestion are presented along with a comparison with feeding mechanisms among other species of Volutidae.

Influence of hydraulic conditions over dunes on the distribution of the benthic macroinvertebrates in a large sand bed river Amsler, Mario Luis; Blettler, Martin Cesar Maria; Ezcurra, Ines Delia This study aims to relate the flow structure over mobile dunes recorded on the channel bed of the Paraná River (Argentina) with the spatial distribution of the benthic macroinvertebrates. The following main conclusions have been obtained: (1) the dunes found in the active channel could be considered as hydraulic biotopes at a mesohabitat scale: the bed forms in the thalweg region are subjected to higher shear stresses with low benthic densities; (2) differences in benthic densities were also recorded at within-dunes microhabitat scales: the largest densities were found in the dune troughs where small bed shear stresses occur and minimum densities on the low stoss side of dunes where turbulent agitation near the bottom strongly disturb the bed particles; (3) superimposed dunes on larger dunes may be considered as another microhabitat of still smaller dimensions. Summarizing, multiscale approaches are needed if a comprehensive understanding linking hydrodynamics and morphodynamics processes with benthic ecology is intended.

Distribución y conservación del ciervo de los pantanos (Blastocerus dichotomus) en la provincia de Santa Fe, Argentina.Resultados Preliminares Eberhardt, María Ayelen Teresita; Antoniazzi, Leandro Raúl; Lartigau, Bernardo Lartigau; Herrera, Pablo; D'Alessio, Santiago El  ciervo de  los pantanos  (Blastocerus  dichotomus)  es  el mayor  cérvido  autóctono  sudamericano  (D`Alessio  y col. 2001). Esta especie se encuentra actualmente presente en una serie de núcleos poblacionales inconexos. Los  registros históricos del ciervo de  los pantanos en  la  provincia  de  Santa  Fe  hacen  referencia  a  su abundancia pasada en las islas del Paraná y territorios aledaños  (Beck-Bernard, 2001; Furlong,  1938; Cabrera y Yepes,  1940),  aunque  en  la  actualidad parece haber desaparecido en la mayor parte del valle del río Paraná (Pautasso,  2008). Son  escasos los datos acerca de  la distribución y el estado de conservación de la  especie en la provincia de Santa Fe. El  presente  trabajo  se  desarrolló  en  el  marco  del proyecto de un Plan Nacional para la Conservación del Ciervo  de  los  Pantanos  impulsado  por  la  Asociación para la Conservación de la Naturaleza (ACEN), con el aval  y  apoyo  de  la  Asociación  Biológica  de  Santa  Fe (BioS)  y  de  la  Dirección  de  Manejo  Sustentable  de Fauna y Flora, Subsecretaría de Recursos Naturales de la  Secretaría  de Medio  Ambiente  de  la  provincia  de Santa  Fe  (Ministerio  de  Aguas,  Servicios  Públicos  y Medio Ambiente). El objetivo fue determinar la distribución  de  esta  especie  en  la  provincia  de  Santa  Fe, generando  información actualizada y precisa sobre su estado de  conservación. Además    a  través del  trabajo de campo se apuntó, en  la medida de  lo posible, a sumar  información  respecto  a  otras  especies  de  interés de conservación y con bajo nivel de conocimiento para la zona.El  estudio  se  restringió  al  sector  nordeste  de  la provincia  de  Santa  Fe  (este  del  departamento  General Obligado y nordeste de San Javier), incluyendo el área donde  se  concentran  los  registros  recientes  para  el ciervo  de  los  pantanos  (Pautasso,  2008; Giraudo  y Arzamendia, 2008),   extendiéndose hacia el sur hasta la localidad de Romang, con el fin de cubrir áreas potenciales de presencia de la especie.El  área  de  estudio  se  dividió  en  10  cuadrículas  de  30 km de lado. Se utilizó el método de encuestas para determinar  ?presencia  / ausencia? de  la especie. Se estableció un mínimo de cuatro entrevistas por cuadrícula, una por cada cuadrante de 15 km de lado.El muestreo se realizó siempre en  territorio santafesino y en los lugares más accesibles.  Las  entrevistas  fueron  de  tipo  informal  (Dietrich, 1995),  y  se  realizaron  a  referentes  locales,  guardafaunas, pescadores y puesteros de establecimientos rura-les que realizan actividades en  la zona de  islas y campos  aledaños  y que  se  consideraron  informantes  válidos.Se realizaron 48 entrevistas a lo largo del área de estudio.En el 28,26% de las encuestas totales se obtuvieron datos positivos para la especie: observaciones directas o  individuos cazados en  los últimos 10 años. Los mismos  corresponden  a  las    cuadrículas  uno,  dos,  tres  y cinco;  comprendidas  entre  Puerto  Ocampo  (S28º  31´ 28.0´´ O  59º  07´  36.8´´)  y  el  Paralelo  28º. El  índice  de presencia, en dichas cuadrículas, estuvo entre 0,17 y  1 (Tabla 1). En el resto del área (20.59 % de las entrevistas  restantes)  se  obtuvieron  datos  históricos  de  su presencia, entre 50 y 100 años atrás.En general, los lugareños coinciden en que los avistajes  de  los  ciervos  son  durante  las  crecientes  o  después de ellas, cuando estos se ven obligados a desplazarse a  lugares más elevados, por  los niveles hidrométricos del   río.A partir del  análisis de las entrevistas realizadas a los pobladores  locales  y  de  la  bibliografía  consultada,  se fue recogiendo elementos e información que permitieron  conformar  una  idea  de  cuáles  son  las  amenazas directas y potenciales que posee el ciervo de  los pantanos en la provincia de Santa Fe. Estos resultados, por lo tanto, ratifican la presencia del  ciervo  de  los  pantanos  en  la  región  noreste  de  la provincia de Santa Fe. Los  registros  obtenidos  en  las localidades de Las Toscas y Florencia permiten hipotetizar  una posible  conexión  con poblaciones  recientemente  reportadas  en  Chaco   y Corrientes. Por  lo  tanto,  los  ejemplares observados en la provincia de Santa Fe, podrían representar un núcleo poblacional relictual en contacto con dichas poblaciones o bien,  ser un  sumidero de las mismas. Las  principales  amenazas  detectadas  son,  la  caza ilegal, el aumento de la actividad ganadera en las zonas (incremento de presencia humana y del contacto de la especie con el ganado) y la falta de conocimiento de la especie por parte de  la comunidad, ya que, en general los encuestados no reconocen   al ciervo de  los pantanos como especie  local. Debido a la situación crítica que se reporta para  la especie  en  la  zona,  la  información  generada  hasta  el momento sobre  la realidad del ciervo de  los pantanos en el nordeste santafesino, junto a la de las provincias de  la  región, debe ser utilizada  rápidamente para   diseñar  estrategias de  conservación a nivel provincial y nacional.

Hacer el desierto: Ensayo y fotografía en la percepción del otro durante la Campaña al Desierto Mailhe, Alejandra Marta ¿Cómo dialogan, para aprehender al "otro", el ensayo y la fotografía producidos entre la "campaña" y los años inmediatamente posteriores a la misma? ¿Qué figuraciones de la identidad propia (letrada, militar, científica) recortan por conüérgencia y/o por contraste? ¿Mediante qué operaciones arbitrarias se aísla, resignificaylo invisibiliza un corpus de prácticas y cuerpos, para forjar al "otro" como objeto de conocimiento y representación? lndagaremos en torno a estos interrogantes a partir del análisis estético e ideológico de Viaie al país de los araucanos (1881) de Estanislao Zeballos y de los álbumes fotográficos producidos porAntonio Pozzo y por Carlos Encina y Evaristo Morenol. Estos universos discursivos traman parte del sentido histórico de las campañas represivas por medio de las cuales se consolidan las fronteras de los modernos estados nacionales. Abordando desde diversas perspectivas los corpus de imágenes producidos por Pozzo y Encina-Moreno, varios críticos (entre otros Vezub, 2002; Tell, 2007 y Ferguson-Alimonda, 2008) han analizado el modo en que la fotografía ligada a la "campaña" subraya la espectacularidad de la irrupción de la civilización sobre el escenario "vacío" del territorio. En este sentido, nos interesa especialmente retontbr sus análisis, indagando comparativamente ensayo y fotografía desde un doble punto de vista: estético e ideológico.; How do the essay and the photography produced between the "Campaña al Desierto" and subsequent years establish a dialogue in order to conceive of the "othe/'? What images of identity in its proper sense (erudite, military, scientific) do they build? How do they isolate, redefine and/or hide a corpus of practices and bodies to define the "othed'as an object of knowledge and representation? We investigate these issues starting with the aesthetic and ideological analysis of Viaje al país de /os ararucanos (1881) by Estalislao Zeballos followed by the photographic albums produced by Antonio Pozzo and Carlos Encina and Evaristo Moreno. These discourses generate part of the historical sense of the repressive campaigns that consolidated the borders of national modern states. In general, Zeballos' essay and the albums celebrate the advance of civilization. They emphasize certain facts and hide others, producing an interpretation that is far from being the "testimony of a historical truth". This vision relates more to the ideology of the subject of enunciation himself than to alterity as such.

FSH and bFGF stimulate the production of glutathione in cultured rat sertoli cells Gualtieri, Ariel Félix; Mazzone, Graciela Luján; Rey, Rodolfo Alberto; Schteingart, Helena Fedora Migration of developing germ cells from the basal to the adluminal compartment of the seminiferous epithelium requires extensive tissue restructuring, resulting in the production of reactive oxygen species. Sertoli cells are involved in this process. Glutathione (GSH), produced by Sertoli cells, has an essential role in cell protection against oxidative stress. Intracellular GSH content is maintained by de novo synthesis, involving glutamate-cysteine ligase catalytic (GCLC) and modulatory (GCLM) subunits, and by recycling from oxidized GSH, catalysed by glutathione reductase (GR). To assess whether follicle-stimulating hormone (FSH) and basic fibroblast growth factor (bFGF) modulate GSH production in Sertoli cells by regulating the expression of GCLC, GCLM and/or GR, we performed in vitro studies using rat Sertoli cells in primary culture. FSH and bFGF stimulation increased Sertoli cell GSH levels after 24 h incubation. The simultaneous addition of FSH and bFGF did not produce any further effect. GCLM expression was upregulated by FSH and bFGF 6 h. At 24 h, only the FSH-mediated effect was still observed. FSH and bFGF also upregulated GR expression. In conclusion, our results show that FSH and bFGF increase GSH levels in Sertoli cells through stimulation of the de novo synthesis and recycling by upregulating GCLM and GR expression respectively. Therefore, protection of germ cells against oxidative stress seems to be regulated by hormones and germ cell-released growth factors capable of influencing the production of Sertoli cell GSH.