Modeling the fiber addition influence on the small strain shear modulus of sand Vettorelo, Paula Vanesa; Clariá, Juan José The mechanical behavior of fiber reinforced soils has been extensively studied in the last decades. Previous studies have shown that inclusion of fibers increases the shear strength of the reinforced soil. However, the presence of fibers can reduce, in some cases, the stiffness of the composite material. In this paper, we study the change on the initial stiffness in alluvial sand reinforced with polypropylene fibers. A model based on Hertz elastic contact theory is developed in order to explain the trends of shear wave velocity and maximum shear modulus in the fiber reinforced sand as the fiber content varies. The model assumes that the shear wave is transmitted through elastic distortions at the contacts, so the stiffness of the contacts governs the initial shear modulus, which in turn is affected by fiber additions. Furthermore, the ratio between the amount of grain to fiber contacts and the total of contacts on the shear wave path influence the maximum shear modulus. An experimental testing program involving confined compression tests with shear wave velocity measurements of unreinforced and fiber-reinforced sand specimens was undertaken to validate the proposed model trends. The model predictions were found to be in good agreement with the experimental results.

Trayectorias de clase y percepciones temporales sobre la posición ocupada en la estructura social: Un abordaje multidimensional de las clases sociales argentinas (2003-2011); Class paths and historical representations of the social class position: A multidimensional approach to the Argentinian social classes (2003-2011) Pla, Jésica Lorena El artículo aborda desde una perspectiva cualitativa las construcciones de sentido, comprendidas como percepciones que los sujetos elaboran con relación a la posición social que ocupan. Lo hace abordando el modo en el que dichos sujetos construyen interpretaciones presentes que incluyen el pasado y el futuro y, a partir de esas elaboraciones, ponen en práctica estrategias para organizar las trayectorias de movilidad social de los integrantes del hogar. La técnica usada fue la de historia de vida, analizadas estas de manera comparativa. De manera general se encontró que el origen social tiene efecto sobre el modo en el cual se construyen dichas percepciones. Las clases sociales mejor posicionadas en la estructura social presentan percepciones relativamente certeras sobre el futuro, referenciadas a las capacidades (propias) de establecer estrategias para lograrlo. En cambio, en quienes experimentan procesos de movilidad intergeneracional de corto alcance y/o de movilidad espuria se observa una idealización del pasado y una inconformidad con el presente que se traduce en incertidumbre con el futuro. En cuanto a las clases trabajadoras, refieren a una mejora en sus condiciones de vida, sustentada en la tríada empleo-seguridad social-consumo y a un contexto (político económico) que mantenga esos elementos.; The article examinates, from a qualitative perspective, the constructions of meaning (perceptions) that people elaborate in relation to the social position they occupy. It does so by approaching the way in which these subjects construct present interpretations, including a past and a future reference and, from these elaborations, they put into practice strategies to organize the trajectories of social mobility of the members of the household. The technique used was that of life history, analyzed in a comparative way. In general it was found that social origin has an effect on the way in which such perceptions are constructed. The social classes best positioned in the social structure present relatively accurate perceptions about the future, referenced to the (own) capacities to establish strategies to achieve it. In contrast, those who experience processes of short-range intergenerational mobility and/or spurious mobility see an idealization of the past, and a disagreement with the present that translates into uncertainty with the future. As for the working classes refer to an improvement in their living conditions, based on the triad employment –social security– consumption and a context (political economic) that maintains these elements.

Characterisation and transferability of transcriptomic microsatellite markers for Nothofagus species El Mujtar, Verónica Andrea; López, María Gabriela; Amalfi, Sabrina; Pomponio, María Florencia; Marcucci Poltri, Susana Noemí; Torales, Susana Discriminant molecular markers are required for research on population genetics, as well as evolutionary studies involving identification of hybrids and parental species, or detection of the genome regions under selection. We provide a set of 27 transcriptomic microsatellite markers (SSRs) for South American Nothofagus species, derived from 73 Nothofagus alpina (=N. nervosa) annotated unigenes. Rates of cross-amplification ranged from 22% to 37%. Genetic characterisation of 22 transcriptomic SSRs for N. alpina and N. obliqua reveals low genetic variability, due to the general occurrence of one major allele at each locus, and high specificity, with few alleles shared between species (14%). At inter-species level 95% of loci were discriminant, with a total G''st over loci of 0.9, indicating that alleles were mostly fixed for all loci in both species. At intra-species level the number of markers with significant differentiation was 2.5 times higher for N. obliqua than for N. alpina populations. Moreover, transcriptomic SSRs showed higher performance compared with published anonymous microsatellites isolated from genome sequences without annotation. This set of transcriptomic microsatellites will be useful to the scientific community working on conservation and evolutionary aspects of Nothofagus species.

A Critical Taxonomy of the Theories About the Paths into the Reduction Perkins, Patricio Agustín The paths or ways to the transcendental reduction are a pivotal phenomenological notion in Husserl’s philosophy. The metaphor of path, in fact, alludes to the demonstrative proofs of transcendental phenomenology. Nonetheless, Husserlian scholarship has not yet been able to end the disputes surrounding this topic, and as a result, competing interpretations continue to prevail. Since existing theories about the paths have not yet been cataloged or analyzed in their global context, I intend to classify the main existing theories about the paths and evaluate the trend established by Iso Kern. Thus, this paper answers the following questions: how many kinds of theories about the paths are there? And, how plausible is the trend and approach initiated by Kern? In order to evaluate each theory, I will compare the interpretation with its exemplary cases. The key contribution of this investigation is therefore twofold: to distinguish with unequivocal concepts the two main trends of hermeneutical theories in play and to evaluate the plausibility of the aforementioned Kernian one. The paper also attempts to show that the hermeneutical approach initiated by Kern has no contextual examples for its conceptual scheme and should consequently be abandoned in favor of an alternative solution.

Confort térmico en espacios verdes urbanos de ambientes áridos.; Thermal comfort in urban green spaces in arid environments Kurban, Alejandra Silvia; Cunsulo, Mario Esteban En la planificación bioclimática de las ciudades y particularmente las ubicadas en ambientes áridos, los espacios verdes representan un potencial higrotérmico desaprovechado como mitigadores del clima urbano. El presente trabajo cuantifica el confort térmico de espacios verdes urbanos (EVU) de una ciudad del centro-oeste de Argentina localizada en la Diagonal Árida Sudamericana, a partir del índice UTCI. Este índice se calcula a partir de mediciones climáticas en 19 EVU, realizadas en el verano del año 2014. El valor de dicho índice en cada EVU se referencia con el calculado para su entorno urbano. El porcentaje de diferencia entre ellos permite agrupar el desempeño bioclimático de los EVU en cinco categorías, en función de su divergencia con las condiciones climáticas generales de la ciudad. Los resultados permiten individualizar los parámetros arbóreos mínimos que deben poseer los EVU, como objetivo de una planificación bioclimática del verde urbano en ciudades de ambientes áridos.; In the bioclimatic planning of cities and particularly those located in arid environments, green spaces represent a missed hygrothermal opportunity as mitigators of urban climate. This article quantifies the thermal comfort of urban green spaces (UGS) in a city in west-central Argentina located in the South American Arid Diagonal, based on the UTCI index. This index was calculated from climatic measurements taken in 19 UGS in the summer of 2014. In each UGS, the value of the UTCI index was compared with that calculated for the urban surroundings. The percentage difference between them was used to group the bioclimatic performance of UGS into five categories according to the divergence with the city´s general climatic conditions. The results made it possible to identify the minimum tree parameters for UGS, as an objective of the bioclimatic planning of urban green areas in cities in arid environments.

Análisis estratigráfico de las secuencias neopaleozoicas de la Precordillera Septentrional; Stratigraphic analysis of the Neopaleozoic sequences in the northern Precordillera Limarino, Carlos Oscar; Schencman, Laura Jazmín; Alonso Muruaga, Pablo Joaquin; Cesari, Silvia Nelida En este trabajo se discuten la nomenclatura estratigráfica, evolución paleoambiental, contenido fósil y edad de las unidades carboníferas y pérmicas de la Precordillera septentrional. El intervalo Mississippiano es caracterizado desde el punto de vista litológico en el área tipo del Grupo Angualasto (Sierra de Malimán), examinando las relaciones con secuencias de similar edad expuestas en otros sectores de la Precordillera (formaciones Jagüel, Agua de Lucho, Cerro Tres Cóndores y Loma de Los Piojos). La evolución paleoambiental de este intervalo incluye varios episodios transgresivos y al menos un evento glacial durante el Viseano-Serpukhoviano temprano. Para el Pennsylvaniano inferior y medio se discute el significado estratigráfico de las formaciones Guandacol y Tupe (Grupo Paganzo), estableciéndose las relaciones con las formaciones Río del Peñón, Quebrada Larga, Panacán y Volcán definidas por autores previos. Todas estas unidades representan la sedimentación postorogénica acaecida luego del levantamiento de la Protoprecordillera ocurrido entre el Devónico tardío y el Mississippiano. Desde el punto de vista paleoambiental este intervalo representa condiciones glaciarias (base de la Formación Guandacol), un evento transgresivo postglacial y la posterior progradación de sistemas fluviodeltaicos (parte media y superior de la Formación Guandacol). Durante la depositación de la Formación Tupe la sedimentación fue dominantemente fluvial e interrumpida por al menos dos eventos transgresivos. Finalmente el Carbonífero más tardío y Pérmico temprano (Gzheliano-Cisuraliano) aparece representado en la Precordillera septentrional por la secuencia de bancos rojos perteneciente a la Formación Patquía, esta unidad resulta temporalmente correlacionable con los miembros medio y superior de la Formación Quebrada Larga o Río del Peñón.; This paper deals with the stratigraphic nomenclature, paleoenvironmental evolution, fossil assemblages and age of the Carboniferous and Permian units outcropping in the northern Precordillera. The Mississippian stratigraphy is characterized in the type area of the Angualasto Group (sierra de Malimán) and the relations with other sequences of similar age exposed in the Precordillera examined in detail (Jagüel, Agua de Lucho, Cerro Tres Cóndores and Loma de Los Piojos Formations). The paleoenvironmental evolution of the Mississippian comprises several transgresive events and at least one glacial episode during the Visean-early Serpukhovian. Regarding the lower and middle Pennsylvanian, the stratigraphic meaning of the Guandacol and Tupe Formations (Paganzo Group) is analyzed, as well as the correlations with the Río del Peñón, Quebrada Larga, Panacán and Volcán Formations which were defined by previous authors in Precordillera. All these units represent the post orogenic sedimentation that took place after the uplift of the Protoprecordillera during the Late Devonian - Mississippian. From the paleoenvironmental point of view, the Lower and Middle Pennsylvanian interval was dominated by glacial conditions (base of the Guandacol Formation), followed by a transgressive postglacial event and the later progradation of fluviodeltaic systems (middle and upper part of the Guandacol Formation). During the deposition of the Tupe Formation, the sedimentation was dominantly fluvial and interrupted by two transgressive episodes. Finally, the red beds of the Patquía Formation records the latest Carboniferous and early Permian (Gzhelian-Cisuralian), this unit is a time equivalent with the middle and upper members of the Quebrada Larga and Río del Peñón Formations.

A high precision U–Pb radioisotopic age for the Agrio Formation, Neuquén Basin, Argentina: Implications for the chronology of the Hauterivian Stage Aguirre-Urreta, Maria Beatriz; Schmitz, Mark; Lescano, Marina Aurora; Tunik, Maisa Andrea; Rawson, Peter F.; Concheyro, Graciela; Buhler, Mariano; Ramos, Victor Alberto A new CA-ID TIMS U–Pb age of 130.39 ± 0.16 Ma is presented here from the Pilmatué Member of the Agrio Formation, lower Hauterivian of the Neuquén Basin in west-central Argentina. This high precision radioisotopic new age, together with the two former ones from the upper Hauterivian Agua de la Mula Member of the Agrio Formation and modern cyclostratigraphic studies in the classical sections of the Mediterranean Province of the Tethys indicate that the Hauterivian Stage spans some 6 Ma, starting ca. 132 Ma and ending ca. 126 Ma. These radioisotopic ages are tied to ammonite biostratigraphy and calcareous nannofossil bioevents and biozones recognized in the Neuquén Basin which in turn are correlated with the Mediterranean standard zones. A new geological time scale for the Valanginian–Hauterivian stages in the Mediterranean region integrating astrochronological and radiochronological data differs with the current official geological time scale which still maintains poorly constraint absolute ages for the Berriasian-Aptian interval.

Synthesis of Gadolinium-based Nanostructures Through an Enzymatic Liposome-controlled Reaction Municoy, Sofia; Bellino, Martin Gonzalo The success of synthesis of varied nanostructures requires the precise precipitation of materials at particular location. Here, gadolinium carbonate nanocapsules or macroporous structures have been successfully synthesized via interplay control on enzymatic precipitation and liposome templating. The nanostructures reflected the shape of the liposomes, where spherical 560 nm size and porous architectures with large pores of 200–300 nm diameter (corresponding to sections along liposomes) ensembles were formed. The manipulation over location of ureases in the liposome system and the temperature-actuated vesicle permeability were crucial factors in determining the morphology of the final product. This liposome-directed enzymatic precipitation represents a powerful yet facile method for lanthanide-based nanostructures synthesis for promising applications.

A new adenovector system for implementing thymulin gene therapy for inflammatory disorders Zappa Villar, María Florencia; López León, Micaela; Pardo, Joaquin; Costa, Mariana Inés; Crespo, Rosana; Dardenne, Mireille; Goya, Rodolfo Gustavo; Reggiani, Paula Cecilia Thymulin is a thymic peptide possessing anti-inflammatory effects. In order to manipulate thymulin expression in gene therapy studies, we built a bidirectional regulatable two-vector Tet-Off system and the corresponding control system. The experimental two-vector system, ETV, consists of a recombinant adenovector (RAd) harboring an expression cassette centered on a Tet-Off bidirectional promoter flanked by a synthetic gene for thymulin and the gene for humanized Green Fluorescent Protein (hGFP). The second adenovector of this system, RAd-tTA, constitutively expresses the regulatory protein tTA. When cells are co-transduced by the two adenovector components, tTA activates the bidirectional promoter and both transgenes are expressed. In the presence of the antibiotic doxycycline (DOX) transgene expression is deactivated. The control two-vector system, termed CTV, is similar to ETV but only expresses hGFP. In CHO-K1, BHK, and C2C12 cells, ETV and CTV induced a dose-dependent hGFP expression. In CHO-K1 cells, transgene expression was almost completely inhibited by DOX (1 mg/ml). After intracerebroventricular injection of ETV in rats, thymulin levels increased significantly in the cerebrospinal fluid and there was high hGFP expression in the ependymal cell layer. When injected intramuscularly the ETV system induced a progressive increase in serum thymulin levels, which were inhibited when DOX was added to the drinking water. We conclude that our regulatable two-adenovector system is an effective molecular tool for implementing short and long-term anti-inflammatory thymulin gene therapy in animal models of acute or chronic inflammation.

El amor de l@s rar@s: cine y homosexualidades durante la década de 1980 en Argentina; Queer love: argentinian films and homosexuality in the eighties Blazquez, Gustavo Este trabajo se detiene en el análisis de los modelos que permiten imaginar y experimentar relaciones (homo)afectivas a partir de una serie de films argentinos. Específicamente nos interesa describir y comparar imágenes elaboradas en el “destape alfonsinista” de mediados de la década de 1980 relacionadas con encuentros homoeróticos. Las películas consideradas son Adiós Roberto (Enrique Dawi, 1985) y Otra historia de amor (Américo Ortiz de Zárate, 1986) que presentan el amor entre los muchachos y Atrapadas (Aníbal Di Salvo, 1984) Correccional de mujeres (Emilio Vieyra, 1986) y Sucedió en el internado (Emilio Vieyra, 1985) que escenifican relaciones lésbicas. Para acercarnos a esas producciones, que reservan el amor para los varones y ubican a las lesbianas en la cárcel, nos valemos de la noción de “guiones sexuales” elaborada por Gagnon y Simon en sus estudios sobre la conducta sexual. El análisis de esas historias de amor y sexo, cinematográficamente objetivadas, permitirá describir cómo se decían/hacían diferencialmente posiciones de género, eróticas, edad, y clase en esos años.; This paper focuses on the analysis of models to imagine and experience (homo)affective relationships in some Argentine films. Specifically we describe and compare images concernin g homoerotic encounters made during the "destape" of the mid - 1980s. The films in question are Adiós Roberto (Enrique Dawi, 1985) and Otra historia de amor (Américo Ortiz de Zárate, 1986) that present the love between men and Atrapadas (Aníbal Di Salvo, 198 4), Correcional de mujeres (Emilio Vieyra, 1986) and Sucedió en el internado (Emilio Vieyra, 1985) that portray lesbian relationships. To approach these texts we use the notion of "sexual scripts" developed by Gagnon and Simon in their studies on sexual be havior. The analysis of these stories of love and sex, cinematically objectified, allow us to describe how gender, eroticism and social class were perfomatively (re)produced in those years. The differences in the ways of doing homosexuality (in)visible dem onstrate the complexity and variations of the sexual morality in the post - dictatorship Argentina culture.

Decomposition from legume and non-legume crop residues: effects on soil organic carbon fractions under controlled conditions; Descomposición de restos de cultivos de leguminosas y no leguminosas: Efectos sobre las fracciones de carbono orgánico del suelo bajo condiciones controladas; Decomposição de resíduos da cultura de leguminosas e não leguminosas: Efeitos, em condições controladas, nas frações de carbono orgânico do solo de Sa Pereira, Eduardo; Duval, Matias Ezequiel; Galantini, Juan Alberto Cover crop (CC) residues protect the soil from erosion and their permanence on the surface is largely influenced by their biochemical constituents. We performed a study under controlled conditions to investigate the dynamics of legume and non-legume CC residues decomposition and the transformations of the soil labile organic carbon fractions in the surface layer (0-15 cm). Theexperiment was carried out on a Typic Argiudoll (clay loam, 27.4 g kg-1 soil organic matter, 14 mg kg-1 extractable phosphorus and 6.5 pH) placed in undisturbed pots (1570 cm3) in a greenhouse under controlled conditions of temperature (25 ± 1 °C). We evaluated three CC species (oat, Avena sativaL.; vetch, Vicia sativa L.; Persian clover, Trifolium resupinatum L.) and a no-CC control (fallow). Shoot residues were applied on the soil surface at 5.4, 5.4 and 2.7 g dry matter (equivalent to 6, 6 and 3 Mg ha-1 for oat, vetch and clover, respectively) and incubated for 362-days (eight sampling times). The water content in the pots was maintained periodically by weight at 60% of soil water-holding capacity. The soil samples were analyzed for particulate organic carbon (POC), and total and soluble carbohydrates (CHt and CHs, respectively). Oat and vetch residues decomposed faster than clover, with the decomposition rate constant (k) values of 1.3, 1.4 and 1.9 year-1, respectively. At the end ofthe experiment, POC concentration was lower in vetch (1.83 g kg-1) and clover (1.96 g kg-1) than in oat (2.21 g kg-1) and fallow (3.00 g kg-1), indicating a loss of 45-64% from their initial values. Soil CHt was influenced by residue quality, where the periods of greatest residue decay (vetch 21-59 daysand oat 93-130 days) corresponded to higher soil CHt. Hence, this organic carbon fraction is sensitive to residue decomposition and can be indicators of changes in soil organic matter over short periods of time.; Los cultivos de cobertura (CC) protegen al suelo de la erosión y su permanencia en el tiempo está influenciada en gran medida por su composición química. Se realizó un estudio en condiciones controladas para investigar la dinámica de descomposición de residuos de CC y las transformaciones de las fracciones orgánicas lábiles en la capa superficial del suelo (0-15 cm). El experimento se llevó a cabo en un Typic Argiudoll (franco arcilloso, 27,4 g kg-1 de materia orgánica del suelo, 14 mg kg-1 de fósforo extraíble y 6,5 de pH) colocado sin disturbar en macetas (1570 cm3 ) en invernadero bajo condiciones controladas de temperatura (25 ± 1 °C). Se evaluaron tres especies de CC (avena, Avena sativa L.; veza, Vicia sativa L. y trébol, Trifolium resupinatum L.) y un control sin CC (barbecho). En la superficie del suelo, se aplicaron 5,4, 5,4 y 2,7 g de materia seca (equivalentes a 6, 6 y 3 Mg ha-1 de avena, veza y trébol, respectivamente) y se incubaron durante 362 días (ocho fechas de muestreo). El contenido de agua en el suelo de las macetas fue mantenido al 60% de la capacidad de retención de agua. En las muestras de suelo se determinó carbono orgánico particulado (POC), y carbohidratos totales y solubles (CHt y CHs, respectivamente). Los residuos de avena y veza se degradaron más rápidamente que el trébol, con tasas de descomposición (k) de 1,3, 1,4 y 1,9 años-1, respectivamente. Al final del experimento, la concentración de POC fue menor en el suelo con veza (1,83 g kg-1) y trébol (1,96 g kg-1) que con avena (2,21 g kg-1) y barbecho (3,00 g kg-1), lo que indica una pérdida de 45-64% de sus niveles iniciales. Los CHt fueron influenciados por la calidad de los residuos, donde los períodos de mayor descomposición de residuos (veza 21-59 días y avena 93-130 días) coinciden con los mayores contenidos de CHt en el suelo. Por lo tanto, esta fracción de carbono orgánico es sensible a la descomposición de residuos y puede ser indicadores de cambios en la materia orgánica del suelo durante cortos períodos de tiempo.; Os resíduos de cobertura (CC) protegem o solo da erosão e a sua permanência na superfície do solo é largamente influenciada pelos seus constituintes bioquímicos. Realizou-se um estudo, em condições controladas, para investigar a dinâmica da decomposição dos resíduos CC provenientes de leguminosas e não leguminosas e as transformações das frações de carbono lábeis na camada superficial do solo (0-15 cm). O ensaio foi realizado em estufa, em condições controladas de temperatura (25 ± 1 °C), num Typic Argiudoll (franco argiloso, com 27,4 g kg-1 de matéria orgânica, 14 mg kg-1 de fósforo extraível e pH 6,5) que foi colocado, sem o perturbar, em vasos (1570 cm3 ). Avaliaram-se três espécies de CC (aveia, Avena sativa L.; ervilhaca, Vicia sativa L. e trevo-da-Pérsia, Trifolium resupinatum L.) e um controlo sem CC (pousio). Na superfície do solo aplicaram-se 5,4; 5,4 e 2,7 g de matéria seca (equivalente a 6; 6 e Mg ha-1 de aveia, ervilhaca e trevo-da-Pérsia, respetivamente) e incubaram-se durante 362 dias (oito datas de amostragem). Nos vasos, o conteúdo em água no solo foi mantido a 60% da sua capacidade de retenção de água. Nas amostras de solo foram analisados o carbono orgânico particulado (POC) e os hidratos de carbono totais e solúveis (CHt e CHs, respetivamente). Os resíduos de aveia e ervilhaca decompõem-se mais rapidamente do que os de trevoda-Pérsia, com valores de taxa de decomposição constante (k) de 1,3; 1,4 e 1,9 ano-1, respetivamente. No final do ensaio, a concentração de POC era mais baixa nos solos com ervilhaca (1,83 g kg-1) e trevo-da-Pérsia (1,96 g kg-1) do que nos solos com aveia (2,21 g kg-1) e em pousio (3,00 g kg-1), indicando uma perda de 45-64% em relação aos valores iniciais. Os valores de CHt no solo foram influenciados pela qualidade dos resíduos, onde os períodos de maior decomposição destes (ervilhaca: 21-59 dias e aveia: 93-130 dias) correspondem às maiores concentrações de CHt no solo. Assim, esta fração de carbono orgânico é sensível à decomposição do resíduo e pode ser um indicador das alterações na matéria orgânica do solo durante curtos períodos de tempo.

Estudio de fluido magnetoreológico con nanopartículas de Níquel y base aceite Mesquida, César Darío; Ramos, Susana Beatriz; Zysler, Roberto Daniel; Soldati, Analía Leticia; Soria, Carlos; Pettinari, Gisela Roxana Los fluidos magnetoreológicos (FMR) son de interés ya que pueden modificar el diseño y el funcionamiento de dispositivos electromecánicos debido a su capacidad de cambiar significativamente su viscosidad bajo la influencia de un campo magnético. Este hecho ha estimulado una intensa actividad de investigación con el objetivo de desarrollar distintas aplicaciones. En este trabajo se sintetizaron y caracterizaron nanopartículas de Ni para su uso como fase dispersaen un FMR utilizando aceite vegetal como fase continua. Para esta suspensión se midió la viscosidad en función del campo magnético y la velocidad de corte, así como el comportamiento viscoelástico en función de una deformación oscilatoria. Se observa que la viscosidad aparente aumenta con el campo magnético aplicado. Además, el campo magnético aplicado induce cambios en las propiedades viscoelásticas del fluido, que pasa a estar dominado por el módulo elástico o de almacenamiento a lo largo de toda la gama de frecuencias ensayadas. El rendimiento viscoelástico de la suspensión de nanopartículas de Ni ensayada revela un interesante comportamiento magnetoreológico, cuando se compara con otros fluidos magnéticos descritos en la literatura, a saber, los desarrollados con partículas comerciales de hierro y óxido de hierro, materiales que generalmente se emplean para este tipo de aplicaciones.; Magnetorheological fluids (MRF) are of interest since they can modify the design and operation of electromechanical devices due to their capacity to significantly change their viscosity under the influence of a magnetic field. This fact has stimulated an intense research activity with the aim of developing applications in electromechanical systems. In this work we synthesized and characterized Ni nanoparticles (Ni NP) for their latter use as a MRF component using vegetal oil as the continuum phase. For this suspension, the shear frequency and magnetic field-dependent viscosity, as well as the viscoelastic behavior as a function of the oscillatory applied load, are measured. It is found that the apparent viscosity increases with the applied magnetic field. Also, the applied magnetic field induces changes in the viscoelastic properties of the fluid, which turns to be dominated by the elastic or storage mode along the whole range of frequencies tested. The viscoelastic performance of the present Ni NP suspension reveals an interesting magnetorheological behavior, when compared to other magnetic fluids reported in the literature, namely, those based on commercial iron and iron oxide particles, materials that are more generally used for this type of applications.

Multiple approaches to understanding the taxonomic status of an enigmatic new scorpion species of the genus Tityus (Buthidae) from the biogeographic island of Paraje Tres Cerros (Argentina) Ojanguren Affilastro, Andres Alejandro; Adilardi, Renzo Sebastián; Cajade, Rodrigo; Ramirez, Martin Javier; Ceccarelli, Fadia Sara; Mola, Liliana Maria Tityus curupi n. sp., belonging to the bolivianus complex, is described from the biogeographically distinct area of Paraje Tres Cerros in north-eastern Argentina. We also present a molecular species delimitation analysis between Tityus curupi n. sp. and its sister species Tityus uruguayensis Borelli 1901 to confirm species integrity. Furthermore, a cytogenetic analysis is presented for these two species which contain different multivalent associations in meiosis, as a consequence of chromosome rearrangements, and the highest chromosome numbers in the genus.

Representantes y representaciones de Argentina en la Organización Internacional del Trabajo en la década de 1920; Argentine's representatives and representations in the International Labor Organization on the 1920´s Stagnaro, Andrés; Caruso, Laura Gabriela El artículo aborda la relación de la Argentina y la Organización Internacional del Trabajo (OIT) a través de los distintos representantes que concurrieron a las Conferencias anuales del organismo durante la década del veinte del siglo pasado, en momentos en que la OIT estaba en proceso formativo. Los informes que estos delegados hicieron públicos -en el caso de los delegados gubernamentales informes elevados a las autoridades, en el caso de los delegados obreros y patronales publicados en diversos medios- permiten analizar las expectativas que portaban al interactuar en un organismo internacional que tenía sus propios objetivos. En muchos casos la OIT fue un escenario más en la disputa entre el estado, los patrones y los obreros, y en otros se puede percibir la uniformidad de criterios en relación a algunos tópicos particulares, tales como el lugar de la Argentina en relación a su legislación laboral. Al mismo tiempo la participación de las delegaciones argentinas exigieron la adecuación del sistema de relaciones establecido entre los sindicatos y el Estado ya que ante la ausencia de un mecanismo formal en la elección de los representantes obreros este fue reemplazado por mecanismos adhoc en el que primaba la coyuntura de conflictividad local; The article approach the relations between the Argentine and the International Labor Organization (ILO) through the different argentine ´s representatives on the ILO´s annual conferences during the formative process on the 1920´s. The representative´s reports –in the case of the government´s representatives those reports were raised to the authorities, in the case of the workers and employers delegates the reports were published in different publications– allowed us to analyze those delegates expectations while they interact with a an organizations with their own objectives. In many cases the ILO was just another stage in the dispute between the state, the workers and the employers, in others we will be able to see the uniformity of criteria in some topics, such as the spot of argentine´s labor legislation. At the same time, Argentine´s participation on the ILO´s conferences demands the adequacy of the relations system between the State and the workers unions. In the absence of this kind of mechanism the workers representative elections depends on the moment of local labor unrest.

Análisis envolvente de datos: Un caso de estudio para una universidad argentina; Data envelopment analysis: A case study for one Argentinian university; Análise envoltória de dados: Um estudo de caso para uma universidade Argentina Villarreal, Fernanda Soledad; Tohmé, Fernando Abel Este artículo presenta un caso de estudio en el que se analiza la eficiencia relativa del plan de estudios de un programa universitario. Esta cuestión es muy relevante, ya que los cursos del plan están financiados con fondos públicos y por lo tanto afectan la eficiencia del gasto público global. El método aplicado es el análisis envolvente de datos (DEA, por sus iniciales en inglés). Los resultados permiten identificar los cursos optativos ineficientes que deberían aumentar el número de estudiantes y reducir al mismo tiempo el número de miembros del cuerpo docente asignados a ellos para mejorar su eficiencia. En el caso de cursos obligatorios, la mejora también requiere reducir el número de docentes auxiliares.; This article presents a study case in which we analyze the relative efficiency of the curriculum of a university degree program. This is a relevant question, since the required courses are publicly funded and thus affect the efficiency of global public spending. The method applied is Data Envelopment Analysis (DEA). Through the our results, we were able to identify inefficient non-mandatory courses that should increase the number of students while reducing the number of faculty members assigned to them to improve their efficiency. In the case of mandatory courses, improvement also requires to reduce the number of adjunct faculty.; Este artigo apresenta um estudo de caso em que a eficiência relativa do currículo de um programa universitário é analisada. Esta questão é muito relevante porque os cursos do plano são de financiamento público e, portanto, afetam a eficiência da despesa pública global. O método aplicado é a análise envoltória de dados (DEA, por sua sigla em Inglês). Os resultados permitem identificar eletivas ineficientes que deveriam aumentar o número de alunos e, ao mesmo tempo, reduzir o número de membros do corpo docente que lhes foram atribuídos para melhorar a sua eficiência. No caso de cursos obrigatórios, a melhoria também requer reduzir o número de assistentes de ensino.

Porphyromona gingivalis, patogeno de relevancia en la enfermedad periodontal Britos, María R.; Sin, Cynthya Solange; Ortega, Silvia Mercedes Porphyromonas gingivalis (P.Gingivalis) es un microorganismo comprometido en el inicio y progresión de la enfermedad periodontal crónica y agresiva, y es considerado su principal agente etiológico. Esta bacteria cuenta con una serie de factores de virulencia que le permiten iniciar el proceso infeccioso, perpetuar la infección y también transformar la placa dental benigna en una comunidad microbiana patógena. Estudiar sus factores de virulencia y su capacidad de modular la respuesta inmunológica del huésped es muy importante para comprender el papel de este patógeno en el desarrollo y establecimiento de la enfermedad. Esta revisión proporciona una visión actual sobre los factores de virulencia y su impacto sobre la respuesta inmunológica en relación con la patogénesis de la enfermedad periodontal.; Porphyromonas gingivalis (P. Gingivalis) is a microorganism involved in the onset and progression of chronic and aggressive periodontal disease, and is considered its main etiological agent. This bacterium has a number of virulence factors that allow it to initiate the infectious process, perpetuate the infection and also transform the benign dental plaque into a pathogenic microbial community. Studying their virulence factors and their ability to modulate the host's immune response is very important in understanding the role of this pathogen in the development and establishment of the disease. This review provides a current view on virulence factors and the irimpac to the immune response in relation to the pathogenesis of periodontal disease.

Artropodofauna cadavérica asociada a cerdo doméstico (sus scrofa) en un ambiente ribereño en Chubut, Argentina; Fauna carrion associated to domestic pig (Sus scrofa) in a coastal environment in Chubut, Argentina Armani, Ana Paula; Dahinten, Silvia Lucrecia V.; Centeno, Néstor Daniel Este es el primer estudio de descomposición cadavérica realizado en un ambiente ribereño en la región NO de la provincia de Chubut Argentina, cuyo objetivo fue determinar la composición específica, la abundancia y la diversidad de la artropodofauna cadavérica asociada a un modelo experimental porcino. Se realizaron muestreos estacionales durante tres años consecutivos (2010 - 2012) utilizando en cada muestreo tres cerdos, colocados dentro de jaulas de madera cubiertas de alambre tejido. Diariamente se colectaron los insectos en el cuerpo, debajo y alrededor de este. Se identificaron y caracterizaron las cinco etapas del proceso de descomposición de los cadáveres de cerdo experimentales. Se recolectaron 6.325 individuos adultos e inmaduros pertenecientes a 63 especies de 18 familias distribuidas entre los órdenes Diptera, Coleoptera e Hymenoptera. Se determinó la estacionalidad de Compsomyiops fulvicrura (Diptera: Calliphoridae) durante la época cálida y la dominancia de Calliphora vicina (Diptera: Calliphoridae) en la época fría. Los resultados obtenidos aportan información relevante sobre la fauna de insectos saprófagos en el ambiente ribereño al río Chubut, que puede ser utilizada como herramienta en la estimación de la data de muerte en casos forenses humanos en la región estudiada.; This is the first study of cadaveric decomposition taking place in a riverside environment of the NW of Chubut province, Argentina. The specific composition, abundance, diversity of the carrion fauna associated with a porcine experimental model was determined. Seasonal samplings were performed for three consecutive years (2010- 2012) using three domestic pigs for each sample, placed in wooden cages covered with wire mesh. Daily, insects were collected in the body, under and around it. There were identified and characterized the five stages of bodies’ decomposition of experimental pigs. Were collected 6,325 individuals adult and immature of 63 species belonging to 18 families distributed among the Diptera, Coleoptera and Hymenoptera orders. During the warm season, was determined the seasonality of Compsomyiops fulvicrura (Diptera: Calliphoridae) and, the dominance of Calliphora vicina (Diptera: Calliphoridae) in the cold season. Relevant information on the saprophagous insects in the riverside environment Chubut, which is helpful in estimating the time of death in forensic cases in the study region.

Revisitando dos estudio clave sobre niños y jóvenes sin domicilio: a propósito de los trabajos de Tobías Hetch y Maryse Marpsat; Rethinking Two Key Studies On Homeless Children and Youth: Regarding the Works of Tobías Hetch and Maryse Marpsat; Revisando dois estudos-chave sobre crianças e jovens sem-teto: sobre o trabalho de Tobias Hetch e Maryse Marpsat Rausky Ndrico, Maria Eugenia Este artículo recupera los aportes de dos trabajos considerados clave en el campo de estudios de niños y jóvenes sin hogar: uno llevado a cabo en Francia por M. Marpsat, J. M. Firdion y equipo "The INED research on homeless", otro, desarrollado en Brasil por T. Hetch "At home in the street", haciéndolos dialogar con una experiencia de investigación conducida en el contexto de la ciudad de La Plata -capital de la provincia de Buenos Aires- sobre niños y jóvenes que trabajan y/o viven en la calle. Se busca hacer una contribución teórica y metodológica a este campo de estudios, a partir del ordenamiento de ciertos ejes de lectura que permitan dilucidar aspectos sustantivos a considerar en investigaciones sobre este colectivo.; This paper focuses on two key research from the area of the social studies on homeless child and youth people: one of them conducted in France by M. Marpsat, J. M. Firdion and their team, “The INED research on homeless”, the other, developed in Brazil by T. Hetch, “At home in the street”. We try to put them in dialogue with a research experience conducted in La Plata —capital of Buenos Aires— about children and youth people who works and/or lives in the streets. This presentation seeks to make a theoretical and methodological contribution to this area of study, sorting out some axis that allows to explain substantive issues to be considered in empirical research on this group.; Neste artigo recupera-se os aportes de duas pesquisas consideradas chave no campo de estudos das crianças e jovens que moran nas ruas: un deles feito na Francia pelo equipe da M. Marpsat y do J.M Firdion “The INED research on homeless”, e outro, desenvolvido no Brasil pelo T. Hetch “At home en the Street”, eles são postos em diálogo com una pesquisa feita na cidade de La Plata –capital do Estado de Buenos Aires- sobre crianças e jovens que trabalhan ou moran nas ruas. Procura-se fazer uma contribuição teórico-metodológica neste campo de estudos, fazendo um ordenamento de alguns eixos de letura que ajudem a elucidar questões substantivas a serem considerados na pesquisa sobre esses grupos.

A high precision U–Pb radioisotopic age for the Agrio Formation, Neuquén Basin, Argentina: Implications for the chronology of the Hauterivian Stage Aguirre-Urreta, Maria Beatriz; Schmitz, Mark; Lescano, Marina Aurora; Tunik, Maisa Andrea; Rawson, Peter F.; Concheyro, Graciela; Buhler, Mariano; Ramos, Victor Alberto A new CA-ID TIMS U–Pb age of 130.39 ± 0.16 Ma is presented here from the Pilmatué Member of the Agrio Formation, lower Hauterivian of the Neuquén Basin in west-central Argentina. This high precision radioisotopic new age, together with the two former ones from the upper Hauterivian Agua de la Mula Member of the Agrio Formation and modern cyclostratigraphic studies in the classical sections of the Mediterranean Province of the Tethys indicate that the Hauterivian Stage spans some 6 Ma, starting ca. 132 Ma and ending ca. 126 Ma. These radioisotopic ages are tied to ammonite biostratigraphy and calcareous nannofossil bioevents and biozones recognized in the Neuquén Basin which in turn are correlated with the Mediterranean standard zones. A new geological time scale for the Valanginian–Hauterivian stages in the Mediterranean region integrating astrochronological and radiochronological data differs with the current official geological time scale which still maintains poorly constraint absolute ages for the Berriasian-Aptian interval.

Functional morphology of comminuting feeding structures of Trichodactylus borellianus (Brachyura, Decapoda, Trichodactylidae), an omnivorous freshwater crab de Azevedo Carvalho, Débora; Viozzi, María Florencia; Collins, Pablo Agustin; Williner, Verónica Crustaceans exhibit great diversity of feeding structures with morphological traits that are useful to infer the general trophic habits of species. In this study, we analyzed the functional morphology of comminuting feeding structures (mandibles, chelipeds, gastric mill) of the freshwater crab Trichodactylus borellianus directly related with the food fragmentation. The heterochely and mechanical advantage (MA) of the chelae were also studied. In both analyses, we considered the relationship between morphology and the natural diet. We expected to find a consistent relation between feeding habits and morphological traits. In general, we found simple structures armed with uniform setal systems and feeding appendages without pronounced teeth or spines. Mandibles have primarily cutting functions, helping with the food anchoring and fragmentation with mandibular palps armed with pappose setae. Chelipeds were covered with spines and simple setae. Adult males exhibited right-handedness with high MA of the major chelae. The ingested, relatively large pieces of food are finally chewed by a gastric mill equipped with sharp cusps characteristic of decapods with low ingestion of crude fiber material. The morphology of the feeding apparatus revealed that it is well adapted to an omnivorous diet, being able to cope with dietary changes.