Calidad, tecnología y mercado de trabajo en la producción del maní de exportación en la Argentina Benencia, Roberto Rodolfo; Fernandez, Elena Mercedes La emergencia de producciones estructuradas en torno a criterios de calidad implicó un cambio de las relaciones sociales, nuevas formas de articulación agroindustrial y mayor supervisión de la agroindustria sobre la producción prim aria, cambios tecnológicos, y cambios en la dem anda laboral. Estos procesos implicaron la racionalización tanto de la organización productiva como laboral. En este trabajo, intentam os m ostrar cómo la introducción del concepto de calidad y su puesta en práctica en relación con el m aní en Córdoba llevaron a producir un cambio de im portancia en el cultivo y el procesam iento en una microrregión; cambio de tal m agnitud que le posibilitó a ésta posicionarse como la segunda exportadora mundial del producto durante la corriente década, al tiempo que implicó la emergencia de nuevos actores, fuertes desplazam ientos de productores, transformaciones tecnológicas de importancia y consecuentes cambios en la dem anda laboral.; The emergence of structured productions supported by quality criteria has implied a social relationships change, new ways of agribusiness linkages, greater agribusiness supervisión on primary production, technological changes, and changes in labour dem and. These processes implied the rationalization of the productive organization and of the labour organization. In this paper, we try to show how the introduction of quality concept and its im plementation in relation to peanut in Córdoba led to produce a signifícant change in cultivation and processing inside a microregion, such is the change m agnitude, that allows this area to positioned as the second world exporter of this product during the current decade meanwhile that implied the emergence of new actors, strong farmers displacements, very im portant technological transform ations and the consequent changes in the labor dem and.

Características de personalidad infantil asociadas al riesgo ambiental por situación de pobreza; Child personality and environmental risk due to poverty Lemos, Viviana Noemí Los factores disposicionales y socioambientales de la personalidad no son elementos separados, deben ser vistos holísticamente como un sistema persona-medio que funciona como una totalidad. Por lo cual un ambiente desfavorecido por la pobreza es una variable socioambiental que interactuaría con las disposiciones del niño pequeño, pudiendo incidir en ciertas características de personalidad. En base a lo mencionado, el objetivo específico de este trabajo fue comparar el perfil de personalidad de niños en riesgo ambiental por situación de pobreza con el de niños sin estas características. Se administró el Cuestionario Argentino de Personalidad Infantil (CAPI) en su versión para niños de 6 a 8 años (Lemos, 2005). Se compararon los perfiles de personalidad de ambas muestras mediante MANOVAs, comparaciones de medias y gráficos de perfiles. A partir de estos análisis, se pudieron observar diferencias significativas tanto a nivel de los factores como de las facetas de personalidad, entre los niños en riesgo por pobreza y los niños no expuestos a esta condición. Las diferencias significativas se presentaron específicamente en el factor Escrupulosidad y en las facetas: competencia, vulnerabilidad, sentimiento gregario y emociones positivas, orden y acción. En relación a los factores y facetas de personalidad en los que no se encontraron diferencias significativas desde el punto de vista estadístico es posible observar, a partir de la comparación de los perfiles de medias de ambos grupos, que la dirección de los resultados encontrados concuerda en general con los patrones vinculados a los aspectos temperamentales de los niños en riesgo que la literatura menciona recurrentemente, como por ejemplo: (a) valores levemente más elevados en el factor de Neuroticismo y (b) valores levemente más descendidos en los factores de Extraversión, Mesura, Escrupulosidad y Apertura.; An individual's context affects the way in which their biological and psychological subsystems function and interacts with each other. While individuals are normally able to manipulate their environment, personality factors increase or diminish their context characteristics, which at the same time influence personality. Heredity and socio-environmental personality factors should not be considered separate elements, but rather a holistic approach as an individual-environment system that functions as a whole. Therefore, an unfavorable environment is a socio-environmental variable that interacts with children's heredity, thus influencing the development of certain personality traits. Based on the above, the specific goal of our research was to compare personality characteristics of children at risk due to poverty and children without risk due to poverty. We applied the Child Personality Questionnaire for Argentina (Cuestionario Argentino de Personalidad Infantil - CAPI) for children aged 6 to 8 (Lemos, 2005). We compared personality profiles from both groups through MANOVA, as well as comparisons of means and graphic profiles. Based on this analysis, we observed significant differences regarding personality factors [F de Hotelling (5, 168) = 2.47; p = .035], as well as facets [F de Hotelling (14, 159) = 2.607; p = .002], among children at risk due to poverty and those who were not. There were significant differences particularly in Conscientiousness [F(1) = 4.35; p = .038] and the following facets: competence [F(1) = 4.652; p = .032], vulnerability [F(1) = 9.732; p = .002], gregariousness and positive affect [F(1) = 8.338; p = .004], order [F(1) = 6.798; p = .010] and action [F(1) = 4.233; p = .041]. The tendencies of the results are as follows: the group at risk scored lower in Conscientiousness, and regarding facets: competence, gregariousness, positive affect, order, action and vulnerability. With regards to Conscientiousness, which includes order, organization and responsibility as facets, Vanistendael (1995) states that children at risk usually have lower levels of achievement motivation. A child's impulsivity and lack of ability to postpone gratification, particularly of children at risk, generally affects them negatively in this aspect. Regarding lower levels in the competence facet, this could be related to other results found in the same group of children at risk, which showed lower levels of self-esteem, as well as of self-sufficiency, and lower levels of self-efficacy (Ghiglione, 2007). In relation to the vulnerability facet, defined for our purposes as lack of independence, we could suppose that depending on someone naturally implies that there be someone who can be depended upon and in whom to seek shelter. These children have little trust in their parents' love and perceive them as unavailable, together with diminished efforts at seeking a social support group and lack of a social network (Richaud de Minzi, 2006). Low scores in relation to the positve affect facet is probably due to the fact that children who are exposed to poverty usually have a more negative view of the world and more feelings of hopelessness (Kotliarenco, 1997). Last but not least, regarding low scores in the action facet, which is part of the Openness factor, in a previous study on coping strategies, this group of children at risk showed more paralization at both cognitive and emotional levels (Richaud de Minzi and Lemos, 2008). In spite of the results which show that children at risk due to poverty have a more vulnerable personality profile, we hope to strengthen their resources through therapeutic interventions. The stories of resilient children show that faith and trust can be developed and sustained, even amidst adverse circumstances. However, this happens only when these children find people who give meaning to their lives, as well as reasons for them to trust life. This is our great challenge.

A low-power integrated circuit for interaural time delay estimation without delay lines Chacón Rodríguez, Alfonso; Martin Pirchio, Franco; Sañudo, Silvana Romina; Julian, Pedro Marcelo A low-power IC for the estimation of the delay between two infinitely clipped (digital) signals is designed and implemented in a 0.35-mum standard CMOS technology. The proposed circuit is based on a sliding-mode control system and does not need past values of the inputs, which are usually stored using chains of digital registers or analog delay lines and significantly increase the power consumption. The IC is intended to work in ultralow-power miniature sensor network nodes performing localization in the audio range [20, 1000] Hz, as part of a forest environmental protection network. Power dissipation results show a core power consumption of 1.04 muW at 3.3 V and only 282 nW at 1.8 V-in both cases with a clock frequency of 200 kHz. The circuit is fully operative and was successfully tested on field as part of a low-power bearing sensor unit.

High-performance sensorless nonlinear power control of a flywheel energy storage system Amodeo, Santiago Jose; Chiacchiarini, Hector Gerardo; Solsona, Jorge Alberto; Busada, Claudio The flywheel energy storage systems (FESS) can be used to store and release energy in high power pulsed systems. Based on the use of a homopolar synchronous machine in a FESS, a high performance modelbased power flow control law is developed using the feedback linearization methodology. This law is based on the voltage space vector reference frame machine model. To reduce the magnetic losses, a pulse amplitude modulation driver for the armature is more adequate. The restrictions in amplitude and phase imposed by the driver are also included. A full order Luenberger observer for the torque angle and rotor speed is developed to implement a sensorless control strategy. Simulation results are presented to illustrate the performance.

Effect of cadaver coatings on emergence and infectivity of the entomopathogenic nematode Heterorhabditis baujardi LPP7 (Rhabditida: Heterorhabditidae) and the removal of cadavers by ants del Valle, Eleodoro Eduardo; Dolinski, Claudia; Barreto, Eduardo L.S.; Souza, R.M. Entomopathogenic nematodes (EPNs) are used for the biological control of soil insect pests worldwide and are generally applied to the soil in aqueous suspension. An alternative application method that could be especially practical and effective under certain conditions is to apply the nematode-killed insect (referred to herein as infected insect cadavers) that are placed on or in the soil and from which the nematodes emerge to seek new hosts. However, physical damage to the insect cadavers during handling and application as well as the potential detrimental impact of various soil biotic and abiotic factors could reduce the efficacy of cadaver applications. Our objective was to test the effectiveness of various protective coverings applied to Galleria mellonella insect cadavers in terms of their potential impact on the emergence and virulence of infective juveniles of the EPN Heterorhabditis baujardi LPP7, and to evaluate whether these coverings influenced cadaver removal by ants (Ectatomma spp.). The protective coveringtreatments included a commercial calcareous powder, a commercial talc powder, and gelatin capsules. The number of emerging infective juveniles (IJs) from insect cadavers formulated with talc powder (9.722 ± 1.382) and gelatin capsules (7.892 ± 1.072) was similar to the control (6.346 ± 1.311), and indicated that these coverings do not interfere with IJ emergence. However, the powdered calcareous covering significantly reduced IJ emergence. High infectivity was observed for IJs that emerged from cadavers in all treatments. Ectatomma spp. ants removed all insect cadavers from the nest entrance to a distance of 20 cm, with the exception of insect cadavers formulated in gelatin capsules, which were not removed. 2009 Elsevier Inc. All rights reserved.

Recovery of normal cytogenetic records in mussels after cessation of pollutant effluents in Puerto Madryn (Patagonia, Argentina) Machado Schiaffino, Gonzalo; Bala, Luis Oscar; Garcia Vazquez, Eva The capacity of coast recovering after interruption of pollution sources has been explored employing mussels as biomarkers. In an area polluted by sewage sludge in Puerto Madryn (Argentina), abnormally high cytogenetic records (micronuclei) had been detected in the mussel Mytilus edulis, even higher than those obtained in this and other mussel species (Brachydontes rodriguezi, Aulacomya atra atra, Perumytilus purpuratus) sampled from heavily polluted industrial areas, and much higher than those recorded in samples from unpolluted areas of the same region. Normal cytogenetic patterns were recovered in Puerto Madryn less than 1 year after cessation of sewage sludge discharges, without additional treatment of the affected area. This discovery opens the possibility of considering restored coastal areas for aquaculture purposes instead of endangering natural populations in virgin areas.

Experimental and theoretical investigation of anaerobic fluidized bed biofilm reactors Fuentes, M.; Mussati, Miguel Ceferino; Aguirre, Pio Antonio; Scenna, Nicolas Jose This work presents an experimental and theoretical investigation of anaerobic fluidized bed reactors (AFBRs). The bioreactors are modeled as dynamic three-phase systems. Biochemical transformations are assumed to occur only in the fluidized bed zone. The biofilm process model is coupled to the system hydrodynamic model through the biofilm detachment rate; which is assumed to be a first-order function of the energy dissipation parameter and a second order function of biofilm thickness. Non-active biomass is considered to be particulate material subject to hydrolysis. The model includes the anaerobic conversion for complex substrate degradation and kinetic parameters selected from the literature. The experimental set-up consisted of two mesophilic (36±1°C) labscale AFBRs (R1 and R2) loaded with sand as inert support for biofilm development. The reactor start-up policy was based on gradual increments in the organic loading rate (OLR), over a four month period. Step-type disturbances were applied on the inlet (glucose and acetic acid) substrate concentration (chemical oxygen demand (COD) from 0.85 to 2.66 g L -1) and on the feed flow rate (from 3.2 up to 6.0 L d-1) considering the maximum efficiency as the reactor loading rate switching. The predicted and measured responses of the total and soluble COD, volatile fatty acid (VFA) concentrations, biogas production rate and pH were investigated. Regarding hydrodynamic and fluidization aspects, variations of the bed expansion due to disturbances in the inlet flow rate and the biofilm growth were measured. As rate coefficients for the biofilm detachment model, empirical values of 3.73?104 and 0.75?104 s2 kg -1 m-1 for R1 and R2, respectively, were estimated.

Las extraordinarias variaciones del Opus 111: Motivos adornianos en torno al estilo tardío de Beethoven Quintana, María Marta El propósito del presente artículo es retomar las consideraciones de Theodor W. Adorno acerca del estilo tardío de Beethoven. El análisis se centra principalmente en las referencias al Opus 111, por tratarse de "una sonata difícil de comprender como obra espiritualmente equilibrada". Indagando en la tesis del filósofo, se busca desentrañar algunos de los presupuestos estético-filosóficos, tales como: la negatividad de la obra de arte y su función crítica. El trabajo se divide en dos momentos: el primero, ubica el pensamiento de Adorno en el marco de la Escuela de Frankfurt (I), y luego avanza sobre la caracterización y análisis del estilo medio (II); el segundo movimiento, se introduce propiamente en el estilo tardío del compositor.; Cet article examine les thèses de h. Adorno à propos du style tardif de Beethoven. L’analyse s’occupe particulièrement des références à l’Op. 111 –considéré par l’auteur comme une oeuvre diicile à comprendre du point de vue de l´esthétique classique– et cherche à approfondir quelques présuppositions esthético-philosophiques d’Adorno, tels que la négativité de l’oeuvre d’art et sa fonction critique de la société.

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.