La patria entre naranjos y cañaverales: Tucumán y el Primer Centenario; The country between orange trees and sugar cane plantation. Tucuman and the first centennial Perilli, Carmen Noemi En 1916 Tucumán proyectó la conmemoración del Primer Centenario de la Declaración de la Independencia. A seis años de las celebraciones porteñas no logró el apoyo que esperaba del gobierno nacional y diseñó un festejo a su medida, en un momento de crisis de la industria azucarera. En este período se registra un enorme movimiento cultural protagonizado por la denominada Generación del Centenario. Sus miembros pertenecen al orden conservador, cuyo poder comienza a disminuir: Sin dejar de lado sus intereses, proyectan una región cultural, fundada en el pasado y la geografía común. Planifican y construyen colecciones, museos y archivos, recopilando tradiciones orales. Entre sus mayores creaciones está la Revista de Ciencias Sociales. Fueron los fundadores de la Universidad. La educación fue el instrumento fundamental para consolidar la región y defenderla de la cultura extranjera y masiva. Estos intelectuales más ideólogos que artistas hacen sus mayores aportes en el campo de las ideas. Se los puede adscribir a lo que Rama llama "Cultura modernizada internacionalista". Su proyecto implica una respuesta regional al cosmopolitismo, una apuesta a una modernización moderada pero, sobre todo, afirma la identidad regional del Noroeste.

A geometrical approach to indefinite least squares problems Giribet, Juan Ignacio; Maestripieri, Alejandra Laura; Martinez Peria, Francisco Dardo Given Hilbert spaces H and K, a (bounded) closed range operator C : H → K and a vector y ∈ K, consider the following indefinite least squares problem: find u ∈ H such that h B(Cu − y), Cu − y i = minx∈H h B(Cx − y), Cx − y i, where B : K → K is a bounded selfadjoint operator. This work is devoted to give necessary and sufficient conditions for the existence of solutions of this abstract problem. Although the indefinite least squares problem has been thoroughly studied in finite dimensional spaces, the geometrical approach presented in this manuscript is quite different from the analytical techniques used before. As an application we provide sufficient conditions for the existence of solutions of some H∞ estimation problems.

A comparison of two methods for acquiring ecological data on armadillos from Argentinean Pampas: field work versus interviews; Comparación de dos métodos para la adquisición de datos ecológicos sobre armadillos en las pampas argentinas: trabajo de campo vs entrevistas Abba, Agustin Manuel; Cassini, Marcelo Hernan The objective of this work is to compare information collected on the ecology of three species of Pampean armadillos (Chaetophractus villosus, C. vellerosus and Dasypus hybridus), obtained through interviews with the information obtained previously in a typical ecological field study. The study area encompasses ~1000km2 of the northeastern part of the Pampas grasslands of Argentina. Thirty four farms evenly distributed throughout the study area were randomly selected and either the farmer or an employee was interviewed on the presence of armadillos. Traditional ecological data were collected in two ways: searching for indirect signs of armadillos and capturing and marking live individuals. The majority of the results were coincident between both methods. It is concluded that interviews can contribute to ecological research in the Pampas grassland by helping to design field surveys in the initial phase of a study. Interviews can be an important tool in decision making regarding land use and management, because they are a low cost method in terms of time and budget, and do provide reliable results.; El propósito de este trabajo es comparar la información acerca de la ecología de tres especies de armadillos de las Pampas (Chaetophractus villosus, C. vellerosus y Dasypus hybridus) recogida a través de entrevistas con aquella información previamente obtenida en un estudio ecológico de campo típico. El área de estudio abarca ~1000km2 del noreste de las Pampas argentinas. Fueron seleccionadas al azar 34 estancias homogé- neamente distribuidas en el área de estudio y se entrevistó a los hacendados o a empleados. Los datos ecológicos tradicionales fueron obtenidos a través de dos maneras: buscando signos indirectos de la presencia de armadillos, y por la captura y marcaje de individuos vivos. La mayoría de los resultados fueron coincidentes en los dos métodos. Se concluye que las entrevistas pueden contribuir a la investigación ecológica en las llanuras pampeanas al ayudar en las fases iniciales de un estudio al diseño de levantamientos en campo. Las entrevistas pueden constituir una herramienta importante en la toma de decisiones acerca del uso y manejo de la tierra, dado que representan un método de bajo costo en términos de tiempo y dinero, a la par de aportar resultados confiables.

Electrokinetic energy conversion in microchannels using polymer solutions Berli, Claudio Luis Alberto Electrokinetic energy conversion in microfluidic systems is a subject of intense research at present, where the main objective is to improve the thermodynamic efficiency of the process. As a novel strategy to the problem, this work focuses on the fluid dynamic properties of the working fluid. It is shown that polymer solutions with wall depletion can substantially increase the conversion efficiency in comparison to simple electrolytes under the same operating conditions. The effect is given by a reduction of the hydrodynamic conductance, while the streaming current is unaltered. It is also found that the maximum efficiency of electrokinetic power generation differs from that of electroosmotic pumping, in contrast to the case of simple electrolytes. This is due to the non-Newtonian character of polymeric fluids, which leads to nonlinear electrokinetic relations.

Inventario y clasificación de manifestaciones basálticas de Patagonia mediante imágenes satelitales y SIG, provincia de Santa Cruz; Inventory and classification of basaltic occurrences of Patagonia based on satellite images and G.I.S, province of Santa Cruz Mazzoni, Elizabeth; Rabassa, Jorge Oscar Las mesetas basálticas constituyen un rasgo típico del paisaje patagónico. Su génesis está vinculada a derrames de lavas máficas que se produjeron en distintos períodos efusivos durante el Terciario y Cuaternario. De acuerdo a su edad, la morfología de los mantos lávicos ha sido modificada por diferentes procesos erosivos. Las coladas más antiguas han quedado sobreelevadas decenas a centenas de metros por procesos de inversión del relieve. En la zona de contacto entre el manto basáltico y la roca subyacente se originan manantiales que brindan un aporte de agua extra al ambiente patagónico extracordillerano, favoreciendo el desarrollo de pastizales húmedos (mallines) que constituyen un recurso natural de alto valor económico, ecológico y escénico. Con el fin de contar con una herramienta que permita evaluar su importancia hidrológica, se llevó a cabo un inventario de estas formas volcánicas en la provincia de Santa Cruz, Argentina. Para ello se aplicaron técnicas de procesamiento digital e interpretación visual de imágenes satelitales de mediana resolución espacial. Los resultados se expresaron cartográficamente y mediante bases de datos, integrándose la información en un entorno S.I.G. Los datos obtenidos para cada campo volcánico, referidos a aspectos topográficos, geológicos y geomorfológicos, superficie del campo lávico y presencia de mallines en sus laderas y áreas próximas, fueron analizados estadísticamente. La información así generada permitió obtener una caracterización general de estas formas del paisaje y diseñar un sistema de clasificación, además de corroborar su importancia en la localización y desarrollo de los mallines.; Basaltic plateaus are a typical feature of the Patagonian landscape. Their origin is associated with basaltic flows that took place in different effusive periods of the Tertiary and Quaternary. According to the age, morphology of the different lava fields has been modified by different erosion processes. The oldest basaltic flows were elevated tens to hundreds of meters by "relief inversion processes". In the contact zone between the basaltic flow and the underlying rock, springs are originated that provide an extra water input to the extra-Andean Patagonian environment, favouring the development of meadows (mallines), a natural resource of high economic, ecological and scenic value. With the aim of providing a tool for evaluating the hydrological importance of meadows, a survey of these volcanic landforms was conducted in the province of Santa Cruz, Argentina. Digital processing and visual interpretation techniques were applied on satellite images of medium spatial resolution. The results were expressed into maps and by means of databases, and the information was incorporated into a GIS environment. Data obtained for each basaltic feature, regarding topographic, geological and geomorphological aspects, area of the lava plateau and presence of meadows on their slopes and proximal areas, were statistically analyzed. The information obtained provided us with a general characterization of these landforms and allowed us to design a classification system whose importance in the location and development of meadows was confirmed.

Aproximaciones a las estrategias de uso e historias tafonómicas de los conjuntos líticos de los sitios ubicados en la cuenca superior del Arroyo Tapalqué (partidos de Olavarría y Benito Juárez, provincia de Buenos Aires, Argentina); Approximation to the use strategies and taphonomic histories of the lithic complexs in the sites located in the upper basin of the tapalqué stream (Olavarría and Benito Juárez district, Buenos Aires province, Argentina) Pal, Nélida Marcela En este trabajo se presentarán los resultados obtenidos del análisis de los artefactos formatizados y de las lascas (con filo naturales con y sin rastros complementarios) de los sitios Laguna La Barrancosa 1 y 2 y Arroyo Tapalqué 1 (Partidos de Olavarría y Benito Juárez, Provincia de Buenos Aires). Los objetivos son: a) evaluar la incidencia de las distintas materias primas (principalmente ortocuarcita y ftanita) en la formación de los rastros de uso sobre los artefactos y la conservación de los mismos, b) determinar sobre qué materiales han sido utilizados los instrumentos y sus modalidades de utilización y c) identificar las alteraciones tafonómicas en los conjuntos líticos. Para cumplir con estos objetivos se aplicará la metodología de análisis funcional de base microscópica. La comparación de los datos obtenidos permitirá explicar las estrategias tecnológicas y actividades desarrolladas por los grupos cazadores recolectores, así como la historia depositacional de los artefactos.

La naturalizacion del “níspero”, Eriobotrya japonica (Thunb.) Lindl. (Rosaceae, Maloideae) en la Argentina Delucchi, Gustavo; Keller, Hector Alejandro Sobre la base de ejemplares de herbario recolectados en nuestro país, se cita por primera vez a Eriobotrya japonica (Thunb.) Lindl. (Rosaceae) como especie naturalizada en la Argentina. Se incluyen observaciones ecológicas y también se brinda información acerca de los diversos usos locales. La especie es descripta e ilustrada; Based on herbarium specimens collected in our country, Eriobotrya japonica (Thunb.) Lindl. (Rosaceae) is mentioned for the first time as naturalized plant in Argentina. Ecological observations and information about various local uses are included. The species is described and illustrated.

Obligatory role in GTP hydrolysis for the amide carbonyl oxygen of the Mg2+-coordinating Thr of regulatory GTPases Zurita, Adolfo Ramón; Zhang, Yinghao; Pedersen, Lee; Darden, Tom; Birnbaumer, Lutz When G-protein α subunits binds GTP and Mg2+, they transition from their inactive to their active conformation. This transition is accompanied by completion of the coordination shell of Mg2+ with electrons from six oxygens: two water molecules, the β and γ phosphoryls of GTP, a helix-α1 Ser, and a switch I domain (SWI) Thr, and the repositioning of SWI and SWII domains. SWII binds and regulates effector enzymes and facilitates GTP hydrolysis by repositioning the γ-carbonyl of a Gln. Mutating the Ser generates regulatory GTPases that cannot lock Mg 2+ into its place and are locked in their inactive state with dominant negative properties. Curiously, mutating the Thr appears to reduce GTP hydrolysis. The reason for this difference is not known because it is also not known why removal of the Thr should affect the overall GTPase cycle differently than removal of the Ser. Working with recombinant Gsα, we report that mutating its SWI-Thr to either Ala, Glu, Gln, or Asp results not only in diminished GTPase activity but also in spontaneous activation of the SWII domain. Upon close examination of existing α subunit crystals, we noted the oxygen of the backbone carbonyl of SWI-Thr and of the γ-carbonyl of SWII Gln to be roughly equidistant from the oxygen of the hydrolytic H 2O. Our observations indicate that the Gln and Thr carbonyls play equihierarchical roles in the GTPase process and provide the mechanism that explains why mutating the Thr mimics mutating the Gln and not that of the Ser.

Characterisation of Argentinean honeys and evaluation of its inhibitory action on Escherichia coli growth Fangio, Maria Florencia; Iurlina, Miriam Ofelia; Fritz, Rosalia The aim of this work was to evaluate the physicochemical, sensory and Escherichia coli growth inhibitory characteristics of honey of different botanical sources from two geographic origin of Argentina. Honeys were obtained from apiaries located in two zones. The floral identification of honeys allowed to clustered them as monofloral, mixed and polyfloral honeys. The study of the physicochemical parameters such as colour, free acidity, pH and moisture showed that the last one reflected significant differences between honeys. These differences were markedly reflected in the average values of moisture content for each zone, being 18.96% and 14.29% to centre and east zone, respectively. In general, honeys evaluated presented an inhibitory effect on the E. coli growth at different periods of time (bacteriostatic action). Only, two of the samples would show a bactericide action against E. coli at 48 h of incubation. Honeys with higher non-hydrogen peroxide activity, were collected from a same geographic place at the same season of year, showing a relationship between the antimicrobial activity and the geographic origin, which could be associated with the typical flora of the place.

Review of the described species of Gonatocerus (Hymenoptera: Mymaridae) in the Neotropical region, with new additions Triapitsyn, Serguei V.; Huber, John T.; Logarzo, Guillermo A.; Aquino, Daniel Alejandro The described Neotropical species of the common and speciose fairyfly genus Gonatocerus Nees ab Esenbeck (Hymenoptera: Mymaridae) are reviewed and re-diagnosed. Eighty-four valid species are recognized including 11 newly described ones. Illustrated identification keys are provided to identify the 5 subgenera recognized in Gonatocerus and to females of each subgenus. The keys include 79 of the treated species, the other five species are known from males only. The known distribution ranges of the species, including new records of extralimital specimens examined, are given. Host associations of the treated species are also given, with emphasis on those species that parasitize eggs of proconiine sharpshooters (Hemiptera: Cicadellidae: Cicadellinae: Proconiini), all of which belong to the ater and morrilli subgroups of the ater species group of G. (Cosmocomoidea Howard), stat. rev. The other four recognized subgenera within Gonatocerus are the nominate subgenus, G. (Gonatocerus) (= sulphuripes species group of authors), G. (Lymaenon Walker), stat. rev. (= litoralis and straeleni species groups of authors), G. (Gastrogonatocerus Ogloblin), stat. rev. (= membraciphagus species group of authors), and G. (Gahanopsis Ogloblin), syn. n. & stat. n. (= deficiens species group of authors). Newly treated as synonyms of G. (Lymaenon) are Rachistus Foerster, Oophilus Enock, Agonatocerus Girault, Gonatoceroides Girault, and Decarthrius Debauche, all syn. n. Two species groups are recognized within G. (Cosmocomoidea) in the New World: the ater group, to which most Neotropical species belong (with the ater, bucculentus, morrilli, and the newly defined chusqueicolus subgroups) and the masneri group, with two described species from the Dominican Republic. The 11 new species described are G. (Gahanopsis) arkadak Triapitsyn sp. n. (Colombia), G. (Cosmocomoidea) barbos Triapitsyn sp. n. (Costa Rica and Mexico), G. (Cosmocomoidea) blefuscu Triapitsyn sp. n. (Costa Rica), G. (Cosmocomoidea) cuscus Triapitsyn sp. n. (Peru), G. (Cosmocomoidea) garchamp Triapitsyn sp. n. (Argentina), G. (Cosmocomoidea) gerasim Triapitsyn sp. n. (Mexico), G. (Cosmocomoidea) hispaniolus Triapitsyn & Huber sp. n. (Dominican Republic), G. (Cosmocomoidea) kiskis Triapitsyn sp. n. (Argentina), G. (Cosmocomoidea) logarzoi Triapitsyn sp. n. (Argentina), G. (Cosmocomoidea) mumu Triapitsyn sp. n. (Argentina), and G. (Cosmocomoidea) rakitovi Triapitsyn sp. n. (Costa Rica). Seven new synonymies are proposed: Gonatocerus h-luteum (Ogloblin) syn. n. under G. (Cosmocomoidea) nigriflagellum (Girault); G. enicmophilus Huber syn. n. and G. necator (Ogloblin) syn. n. under G. (Cosmocomoidea) bonariensis (Brèthes); G. dimorphus (Ogloblin) syn. n. and G. monrosi (Ogloblin) syn. n. under G. (Gastrogonatocerus) margiscutum Girault; and G. setulosus (Ogloblin) syn. n. and G. dorsiniger (Ogloblin) syn. n. under G. (Gastrogonatocerus) membraciphagus Ogloblin. Litus maculipennis Ashmead, Gahanopsis deficiens (Ogloblin), and Gahanopsis straeleni (Debauche) are transferred to Gonatocerus as, respectively, G. (Cosmocomoidea) maculipennis (Ashmead) comb. n., G. (Gahanopsis) deficiens (Ogloblin) comb. n., and G. (Lymaenon) straeleni (Debauche) comb. n. Lectotypes are designated for the following 23 species: G. (Gahanopsis) acanophorae (Ogloblin), G. (Gahanopsis) aethalionis (Ogloblin), G. (Cosmocomoidea) annulicornis (Ogloblin), G. (Gastrogonatocerus) anomocerus Crawford, G. (Gonatocerus) appendiculatus (Ogloblin), G. (Gonatocerus) bonaerensis (Ogloblin), G. (Cosmocomoidea) caudatus (Ogloblin), G. (Cosmocomoidea) concinnus (Ogloblin), Lymaenon (Gastrogonatocerus) dimorphus Ogloblin, G. (Gonatocerus) excisus (Ogloblin), G. (Cosmocomoidea) gracilicornis (Ogloblin), G. (Cosmocomoidea) grandis (Ogloblin), Lymaenon h-luteum Ogloblin, G. (Cosmocomoidea) inauditus (Ogloblin), G. (Gastrogonatocerus) juvator Perkins, G. (Gastrogonatocerus) margiscutum Girault, G. (Cosmocomoidea) metanotalis (Ogloblin), G. (Cosmocomoidea) nasutus (Ogloblin), Lymaenon necator Ogloblin, G. (Cosmocomoidea) nigrithorax (Ogloblin), G. (Lymaenon) pratensis (Ogloblin), G. (Gonatocerus) stenopterus (Ogloblin), and G. (Gonatocerus) urocerus (Ogloblin).

A 20 años de "Sujetos, disciplina y curriculum": Itinerarios y lecturas de un clásico Southwell, Myriam Monica Esta obra (Sujetos, disiciplina y curriculum) instaló un modo - no excluyente- de indagar los problemas del pasado educativo aunando enfoques, modalidades de escritura y perspectivas de análisis no desarrolladas hasta entonces. Si bien la obra de Puiggrós debe ubicarse en un marco donde tuvo lugar -desde distintas perspectivas y enfoques- una revisión de los argumentos expuestos por la historiografía tradicional, aquél trabajo reúne y conjuga una serie de rasgos que invitan a preguntarse qué se abre y que se cierra en la historiografía educativa argentina con la publicación de "Sujetos, disciplina y curriculum"

¿Pirámides y Palmeras o Pirámides y Faraones?: Adaptación y validación de un test de asociación semántica al español rioplatense; Pyramids and palm trees or pyramids and pharaohs?: Adaptation and valifation of semantic association test to the spanish Martínez Cuitiño Carricaburo, María Macarena; Barreyro, Juan Pablo La memoria semántica es definida como el sistema que permite almacenar el significado de las palabras, objetos, conceptos y el significado del mundo en general. El test más utilizado para evaluar los déficit semánticos adquiridos es el Test de Pirámides y Palmeras (Howard & Pat - ter son, 1992). Es una prueba de asociación semántica que se administra desde diferentes modalidades (pictórica y verbal) y se encuentra muy condicionada por el medio socio cultural. Los objetivos de este trabajo son: presentar la adaptación y validación del Test de Pirámides y Palmeras al español rioplatense, comparar una versión original del test con una nueva versión abreviada y modificada, denominada Test de Pirámides y Faraones, comparar el rendimiento entre sujetos normales y pacientes y obtener puntajes de corte para el diagnóstico de dificultades semánticas en ambas versiones. El test se administró en forma computarizada a 50 voluntarios (40 controles y 10 pacientes con demencia semántica). De las 66 tríadas adaptadas y construidas se seleccionaron las 20 que mejor discriminaron entre pacientes y controles. La fiabilidad del test original fue de alpha igual a .857 para la modalidad pictórica y alpha igual a .910 para la modalidad verbal. La del nuevo test fue de alpha igual a .917 para la modalidad pictórica y alpha igual a .918 para la modalidad verbal. Se obtuvo así la adaptación y validación del Test de Pirámides y Palmeras, co mo así también una versión abreviada, el Test de Pirámides y Faraones, que evalúa adecuadamente la memoria semántica en nuestro medio sociolingüístico y se adecua a los requerimientos clínicos actuales.; Semantic memory is a long term memory system proposed by Tulving (2000) that stores objects, words, and general world knowledge’s meanings without connection with any particular time or place. Conceptual knowledge is mostly shared across individuals in a given culture, although its precise scope depends on the individual’s experience (Hodges & Patterson, 1997; Patterson & Hodges, 1995). Semantic memory may be impaired in many neurological disorders. This disruption may be attributed to pathology in the infer-lateral temporal lobes. Patients with semantic dementia have difficulties with objects and words meanings (Budson & Price, 2005). Pyramids and Palm Trees Test is one of the most used measures to assess acquired semantic impairments (Howard & Patterson, 1992). It’s a semantic association test and has six different administration modalities: pictorial, verbal, and combined. This test contains 52 triads. The English normative data from the original Pyramids and Palm Trees Test Manual (Howard & Patterson, 1992) was only obtained in 13 young adults, and no participant made more than three errors. This is a socio-cultural influenced test. The aims of this article are to present the Pyramids and Palm Trees Test adaptation and validation to our language (Spanish) and cultural context, to compare the 52 triads from the original version with a new and shorter 20 triads version, to assess differences in performance between controls and patients in both tests, and to get cutoff scores on both versions. A computerized version of the original test (52 triads) plus 14 new triads (66 triads in total) were administered to 50 volunteers (40 controls and 10 semantic dementia patients). Presentation pro - gram was used to present the stimulus. Non frequent cultural associations were omitted: (a) windmill, tulip-daffodil, (b) carrot, lamb-donkey, (c) acorns, donkey-pig, and (d) Eskimo-rowing, boat-kayak. Also, others triads were slightly modified: (a) caterpillar, butterfly-dragonfly by caterpillar, butterfly-ant, (b) Eskimo, igloo-house by Indian, carp-house, (c) crook, sheep-mice by dog, rabbit-mice, (d) padlock, bicycle-car by pump, bicycle- car, (e) blackboard, table-desk by blackboard, pen-chalk, (f) eggs, hen-swan by flock, hen-duck, and (g) soldier, church-castle by knight, church-castle. Triads with composed words in Spanish were changed: (a) safety pin (alfiler de gancho), girlbaby by pacifier, girl-baby, (b) safe (caja fuerte), necklace-tie by jacket (chaleco), necklace-tie, and (c) bath, owl-woodpecker (pájaro carpintero) by bath, owl-canary. Of the 66 adapted triads, the 20 that allowed better discrimination between pa - tients and controls were selected. The new and shorter version is called Pyramids and Pharaohs, because the Pyramids and Palm Trees Test triad had low specificity and moderate sensitivity in our sample and wasn´t selected. In the adapted Pyramids and Palm Trees Test the reliability index of the pictorial version was moderately high (α = .857), and high for the verbal modality (α = .910). In the Pyramids and Pharaohs Test the reliability index was high for both versions (pictorial: α = .917; verbal: α = .918). The cutoff score for the original version was 44 for the pictorial modality and 43 for the verbal modality. In the Pyramids and Pharaohs Test the cutoff score was 17 for the pictorial modality and 18 for the verbal one. Regarding the specificity, the adapted Pyramids and Palm Trees Test was high (98.8%) same as the new shorter test. In relation to the sensitivity, the original test was moderate (70%), lower than the Pyramids and Pharaohs Test (85%). Results indicate that the Pyramids and Palm Trees Test can be considered an appropriate adaptation to our social culture. Moreover a new test was designed, Pyramids and Pharaohs, with only 20 triads, adequate for semantics acquired impairments assessment, useful for the research on cognitive processes and current clinical re - quirements.

Tecnología, territorio y sociedad: Producción de biodiesel a partir de aceites usados; Technology,Territory and Society: Biodiesel Production Based on Waste Oil Garrido, Santiago Manuel Desde el año 2002, se desarrollaron en Argentina distintas experiencias vinculadas a la producción de biodiésel a partir de aceites vegetales usados. El desarrollo de estas experiencias puede ser interpretadas como una trayectoria socio-técnica en la que se articularon diferentes grupos sociales, técnicas y condiciones socio-demográficas generando distintos estilos socio-técnicos.La reconstrucción de esta trayectoria permite entender cómo se desarrollan los procesos de co-construcción de tecnologías, regulaciones, dinámicas económicas y prácticas sociales; más,cuando en el caso analizado, el aprovechamiento de desechos puede resolver problemas tanto ambientales como económicos y sociales.; Since 2002, a number of experiences have developed in Argentina related to biodiesel production based on waste vegetable oils. The development of these experiences can be interpreted as a socio-technical trajectory in which different social and technical, and different socio-demographic conditions were articulated, generating distinct socio-technical styles. The reconstruction of this trajectory makes possible an understanding of how processes of co-construction of technologies, regulations, economic dynamics and social practices develop. In the case analyzed, this reconstruction will permit observation of how the use of waste material can resolve environmental as well as economic and social problems.

Marcuse y una mirada desde la cultura digital Murolo, Norberto Leonardo Uno de los autores más influyentes de la Escuela de Frankfurt es, sin dudas, Herbert Marcuse. Sus conceptualizaciones expresan una crítica aguda al modo en que la sociedad occidental reconfiguró el espacio público durante la segunda posguerra, donde hubo ganadores y perdedores. De allí que sus conceptos centrales adviertan un uso ideologizado del lenguaje para entender la historia, la sexualidad y la autoridad. Claro está que en esta concepción, como en varias de las propuestas de la Escuela de Frankfurt, se parte de conceptualizaciones marxistas y freudianas. Sin embargo, en Marcuse, como en ningún otro de sus exponentes, el psicoanálisis se erige como la teoría esencial para el entendimiento de la vida en sociedad. El lenguaje unidimensional al que se refiere Marcuse es aquel que emplea los opuestos como construcciones válidas, que genera contradicciones desapercibidas, sentencias carentes de base; es un lenguaje que, por definición, no estimula la criticidad y la reflexión, y no releva más lecturas que la propuesta. El conformismo conceptual alcanzado mediante relaciones asentadas en la economía, es el punto central de una sociedad semantizada mediante un lenguaje cosificado. Producción y reproducción del lenguaje ilimitan el alcance del poder. La autoridad se vale de esta arma para dictar, mediante fórmulas míticas y estereotipadas, un modo de vida válido para ser incluido en el engranaje de la ciudadanía.

Sensitivity of different taxonomic levels of soil Gamasina to land use and anthropogenic disturbances Bedano, José Camilo; Ruf, Andrea The effect of taxonomic level on the sensitivity of bioindicators has been widely investigated in aquatic ecosystems and, to a lesser extent, in terrestrial ecosystems. However, no studies have been conducted on the sensitivity of the different taxonomic levels of soil mites, especially Gamasina, to human activities. The present study aimed to assess the sensitivity of different taxonomic levels of soil Gamasina mites to anthropogenic disturbances in Europe and Argentina. We arranged the data from previous projects in a hierarchical system and conducted a study to identify the critical taxonomical levels that had the highest discriminative potential between sites (Europe and Argentina) or management types (forests, grasslands, fallows, succession, recultivation and agricultural sites). For the Gamasina community, geographical location was by far more important than the influence of any land use type. The analysis including only the European sites demonstrated that communities belonging to sites subjected to different land uses were also significantly different. The species data set provided a clearer separation of sites according to both the geographical and the land-use gradients than the genus and family data sets. The genus and, to a lesser extent, the family approach may be sufficient to elucidate the influence of great geographical differences and also of certain land uses (e.g. grasslands from the forests and arable sites).5 Species presence/absence data provided valuable information in our analyses, although the use of quantitative data yielded a clearer separation of sites.

The effect of factor interactions in Plackett-Burman experimental designs: Comparison of Bayesian-Gibbs analysis and genetic algorithms Magallanes, Jorge Federico; Olivieri, Alejandro Cesar A genetic algorithm has been developed in order to estimate not only the main effects but also the association of terms when analyzing the influence of experimental factors through a Plackett-Burman design of experiments. The results for a series of simulated systems as well as experimental examples show excellent agreement with a Bayesian-Gibbs approach. The Plackett-Burman design is usually employed for screening, but its performance depends on the assumption that the interaction effects are negligible. Simulations allow one to analyze the effect of increasing interactions on the significance of main factors when Plackett-Burman designs are processed by neglecting factor associations.

Nota sobre la dieta del pato cuchara: Anas platalea (Aves: Anatidae) en Santa Fe, Argentina Beltzer, Adolfo Hector; Quiroga, Martin Anibal; Medrano, J. J. Se presenta el resultado del análisis del contenido estomacal de Anas platalea (Vieillot, 1816). El espectro estuvo compuesto de efipios, semillas, insectos y moluscos. Los primeros utilizan su resistencia a los jugos gástricos como una estrategia de dispersión en el grupoAnas platalea (Vieillot, 1816). El espectro estuvo compuesto de efipios, semillas, insectos y moluscos. Los primeros utilizan su resistencia a los jugos gástricos como una estrategia de dispersión en el grupo

Size of precipitation pulses controls nitrogen transformation and losses in an arid Patagonian ecosystem Yahdjian, María Laura; Sala, Osvaldo Esteban Arid ecosystems receive precipitation pulses of different sizes that may differentially affect nitrogen (N) losses and N turnover during the growing season. We designed a rainfall manipulation experiment in the Patagonian steppe, southern Argentina, where we simulated different precipitation patterns by adding the same amount of water in evenly spaced three-small rainfall events or in one-single large rainfall event, three times during a growing season. We measured the effect of the size of rainfall pulses on N mineralization and N losses by denitrification, ammonia volatilization, and nitrate and ammonia leaching. Irrigation pulses stimulated N mineralization (P < 0.05), with small and frequent pulses showing higher responses than large pulses (P < 0.10). Irrigation effects were transient and did not result in changes in seasonal net N mineralization suggesting a long-term substrate limitation. Water pulses stimulated gaseous N losses by denitrification, with large pulses showing higher responses than small pulses (P < 0.05), but did not stimulate ammonia volatilization. Nitrate leaching also was higher after large than after small precipitation events (P < 0.05). Small events produced higher N transformations and lower N losses by denitrification and nitrate leaching than large events, which would produce higher N availability for plant growth. Climate change is expected to increase the frequency of extreme precipitation events and the proportion of large to small rainfall events. Our results suggest that these changes would result in reduced N availability and a competitive advantage for deep-rooted species that prefer nitrate over ammonia. Similarly, the ammonium:nitrate ratio might decrease because large events foster nitrate losses but not ammonium losses. © 2010 Springer Science+Business Media, LLC.

A synthesis route of gold nanoparticles without using a reducing agent Vargas-Hernandez, C.; Mariscal, Marcelo; Esparza, R.; Yacaman, M. J. In the present work we show that synthesis of gold nanoparticles (NPs) could be performed by microwave-assisted technique without the need of adding any reducing agent. Only water and the gold salt precursor are necessary to generate the NPs under the influence of microwaves. The produced NPs have been characterized by state-of-art microscopy techniques, like high resolution transmission electron microscopy, scanning electron microscopy, and energy-dispersive X-ray. Theoretical calculations have been performed to support the experimental findings. It is expected that the present work opens routes for synthesis of NPs using green, fast, and safe methods. © 2010 American Institute of Physics.

Revisiting the Intertropical Brazilian Species Hoplophorus euphractus (Cingulata, Glyptodontoidea) and the Phylogenetic Affinities of Hoplophorus Porpino, Kleberson de O.; Fernicola, Juan Carlos; Bergqvist, Lílian P. The genus Hoplophorus is one of the most distinctive glyptodonts from the Quaternary deposits of the intertropical area of Brazil. In this paper, we redescribe cranial and postcranial elements and describe some new tarsal elements belonging to the species Hoplophorus euphractus from caves from Minas Gerais state, southern Brazil, in order to provide a better diagnosis for the genus. The material examined shows several striking, distinctive characters relative to Neosclerocalyptus, besides those previously reported, reinforcing the validity of Hoplophorus. On the other hand, we find that the postcrania of Hoplophorus presents striking, unreported resemblances with Panochthus (e.g., more lateromedially elongated cuboid facet of navicular and caudal tube with large lateral figures separated from the terminal ones by a wide space). In order to infer the relationships of Hoplophorus and to reevaluate the monophyly of the tribe Hoplophorini and the subfamily Hoplophorinae (in which Hoplophorus was previously allocated), we carried out a cladistic analysis of 18 taxa, including 13 glyptodont genera and five cingulate outgroups, scored for 151 cranial, dental, and postcranial characters. The most parsimonious tree shows that Hoplophorinae and Hoplophorini are both paraphyletic and has Hoplophorus as the sister group to Panochthus based mostly on synapomorphies of the caudal tube. We propose: (1) restricting the definition of the tribe Hoplophorini to the lineage represented by Hoplophorus, making it the sister group to Panochthini within Panochthinae (= Hoplophorus + Panochthus); and (2) a new subfamily, Neosclerocalyptinae, represented by Neosclerocalyptus, the sister group to Panochthinae.