"Podría ser así, o quizá todo lo contrario, o nunca existió" Futura: diseñando una utopía sensible Gatto, Ezequiel Guillermo En 1968 se presentó una obra de teatro experimental en el Instituto Di Tella, laboratorio artístico de las nuevas vanguardias estéticas urbanas. La peculiaridad de esta obra, dirigida por Alfredo Rodríguez Arias, extraía su fuerza escénica del conjunto de problemas planteados por el urbanismo. Mezcla de diagnóstico sobre las condiciones sociopolíticas de la vida en la ciudad y apuesta hacia el porvenir, un conjunto de reconocidas voluntades arquitectónicas formularon ciertos tópicos que luego se vieron expresados en Futura. Un cruce que daba cuenta de la fluida comunicación, en aquel período, entre arquitectura y prácticas estéticas, imaginando, en este caso, un tiempo por venir en el que la convivencia amistosa y recíproca reformularía las instituciones formales y las condiciones mismas de la vida en común.

La cadena del cuero en la Argentina: Tensiones estructurales, problemas de coyuntura y dilemas de la política en la posconvertibilidad; The leather chain in Argentina Schorr, Martín El comportamiento de la cadena de valor del cuero en la Argentina ha sido determinado por la rigidez estructural de su oferta y la legislación sectorial. Ambos aspectos tendieron a fortalecer el eslabón intermedio intensivo en capital y fabricante mayormente de commodities destinadas a la exportación, resultando en un segmento de manufacturas poco relevante. El sistema de incentivos sumado a la protección actual del mercado interno tiende a la sustitución en los bienes finales del cuero por otras materias primas que no gozan de ventajas comparativas y a la especialización en bienes de menor valor agregado en curtiembres. Sin embargo, es posible poner en marcha una serie de medidas de política que reviertan esta tendencia en pos del valor agregado y el empleo con orientación al mercado externo.; The behavior of the leather value chain in Argentina has been determined by the structural rigidity of its supply and the sectorial legislation. Both aspects have tended to strengthen the intensive intermediate link in capital and producer of commodities mostly for export, resulting in a small manufacturing segment with little relevance. The incentive system and the current protection of the domestic market tend to replace leather substitution with other raw materials in the final goods without comparative advantages and the specialization in lesser value added goods in tanneries. However, it is possible to start some policies to reverse this trend towards value added and employment orientated to the foreign market.

Sátira y filosofía en los studia humanitatis: La inluencia de Luciano y Epicuro en Lorenzo Valla, León Battista Alberti y Tomás Moro Vilar, Mariano Alejandro Durante el siglo XV el renovado interés en la recuperación de la cultura clásica trajo a la luz el De rerum natura de Lucrecio y las Vidas y opiniones de los filósofos más ilustres de Diógenes Laercio, lo que impulsó la nueva valoración del epicureísmo que ya había comenzado incluso antes de estos hallazgos. Simultáneamente, la utilización de los textos de Luciano de Samosata por parte de Manuel Crisoloras en sus cursos de griego en la ciudad de Florencia provocó una serie de imitaciones y reformulaciones del modelo satírico propuesto por este autor. En este trabajo analizaremos la forma en la que la influencia de Luciano fue útil para Lorenzo Valla, León Battista Alberti y Tomás Moro para darle forma a sus representaciones y reapropiaciones de la filosofía epicúrea y parodiar el ethos filosófico desde distintas perspectivas. Para esto nos concentraremos en el De vero falsoque bono (1433), el Momus sive principe (1450) y la Utopia (1516).; During the fifteenth century, the new interest in the recovery of the ancient culture brought to light the De rerum natura from Lucretius and the Lives and Opinions of Eminent Philosophersfrom Diogenes Laërtius. Both texts had an impact on the new interest in the epicurean sect, which had begun before this findings. At the same time, the utilization of texts from Lucian of Samosata by Manuel Chrysoloras in his Greek classes in the city of Florence provoked a series of imitations and reformulation of the satiric works of this author. In this article, we propose an analysis of the particular way in which Lorenzo Valla, Leon Battista Alberti and Thomas More used the satiric model from Lucian to present their representation and reformulation of the epicurean ideas, and to mock the philosophical ethos from different perspectives. From this point of view we will focus on three works: De vero falsoque bono (1433), Momus sive de principe (1450) and the Utopia (1516).

El rol de la democracia en la planificación urbana: caso ciudad de Rosario, Argentina (1983-1993); The role of democracy in urban planning: case Rosario city (1983-1993) Galimberti, Cecilia Inés La crisis del modelo de planificación tradicional ante la necesidad de abordar el territorio con una mirada cercana y directa a la “ciudad real”, analizada como un complejo sistema dinámico; trasciende internacionalmente en las esferas académicas, profesionales y administrativas. El presente artículo se propone analizar cómo ocurre este cambio de planificación en la ciudad de Rosario, Argentina; coincidente con la recuperación del gobierno democrático en 1983. La administración local democrática resignifica las ideas y debates en torno al rol de la arquitectura en la ciudad, ya establecidas desde finales de la década de 1970 en otras instituciones rosarinas como son la Facultad de Arquitectura y el Centro de Arquitectos Rosario; a fin de afrontar un nuevo compromiso frente al escenario contemporáneo de las demandas colectivas, reconociendo la caducidad de los instrumentos urbanísticos existentes de planificación. Es a partir de la articulación de diferentes actores en diversas instituciones, enriquecidos por la circulación internacional de nuevas ideas y estrategias urbanísticas, que se prefigura un cambio en la manera de soñar y transformar físicamente la ciudad; el cual se posibilita por el retorno de la democracia que permite la continuidad de políticas urbanas con lineamientos y objetivos esenciales de transformación de la ciudad basadas en el sentido colectivo de las necesidades sociales y en la actualización permanente del conocimiento de la ciudad real como el camino para construir cotidianamente el proyecto continuo de compromiso democrático.; The crisis of the traditional planning model before the need to approach the territory with a close and direct look to the "real city", analyzed as a complex dynamic system, goes beyond internationally in the academic, professional and administrative spheres. The present article attempts to analyze how this change takes place in the planning of the city of Rosario, Argentina, coinciding with the recovery of democratic government in 1983. Democratic local government redefines the ideas and debates on the role of architecture in the city, established since late 1970 in Rosario's other institutions such as the College of Architecture and the Center of Architects from Rosario in order to face a new commitment towards the contemporary scene of the collective demands, recognizing the expiration of the existing urban planning instruments. It is from the articulation of different actors in diverse institutions, enriched by the international flow of new ideas and planning strategies, that a change in the way of dreaming and physically transforming the city is foreshadowed, which is made possible by the return of democracy that allows the continuity of urban policies with essencial guidelines and targets of city transformation based on the collective sense of social needs and on the permanent updating of the real city knowledge as the way to build the ongoing project of democratic commitment.

Electrode and brain modeling in stereo-EEG Von Ellenrieder, Nicolás; Beltrachini, Leandro; Muravchik, Carlos Horacio Objective: To quantify the perturbation due to the presence of a measuring depth electrode on the intracranial electric potential distribution, and to study the effect of the heterogeneity and anisotropy of the brain tissues' electric conductivity. Methods: The governing differential equations are solved with the Boundary Elements Method to compute the perturbation on the electric potential distribution caused by the presence of the measuring electrode, and with the Finite Elements Method to simulate measurements in an heterogeneous anisotropic brain model. Results: The perturbation on the measured electric potential is negligible if the source of electric activity is located more than approximately 1. mm away from the electrode. The error induced by this perturbation in the estimation of the source position is below 1. mm in all tested situations. The results hold for different sizes of the electrode's contacts. The effect of the brain's heterogeneity and anisotropy is more important. In a particular example simulated dipolar sources in the gray matter show localization differences of up to 5. mm between homogeneous isotropic and heterogeneous anisotropic brain models. Conclusions: It is not necessary to include detailed electrode models in order to solve the stereo-EEG (sEEG) forward and inverse problems. The heterogeneity and anisotropy of the brain electric conductivity should be modeled if possible. The effect of using an homogeneous isotropic brain model approximation should be studied in a case by case basis, since it depends on the electrode positions, the subject's electric conductivity map, and the source configuration. Significance: This simulation study is helpful for interpreting the sEEG measurements, and for choosing appropriate electrode and brain models; a necessary first step in any attempt to solve the sEEG inverse problem. © 2012 International Federation of Clinical Neurophysiology.

C343 behavior in benzene/AOT reverse micelles. the role of the dye solubilization in the non-polar organic pseudophase Gutierrez, Jorge A.; Falcone, Ruben Dario; Silber, Juana J.; Correa, Nestor Mariano The behavior of coumarin 343 (C343), a common molecular probe utilized in solvation dynamics experiments, was studied in water/sodium 1,4-bis-2- ethylhexylsulfosuccinate (AOT)/benzene reverse micelles (RMs). In all the studies performed until now, C343 was not soluble in the organic solvent used to create the RM systems (namely different alkanes such as n-heptane, cyclohexane or isooctane). In this work we have chosen benzene as the organic solvent because C343 is completely soluble at the work concentration used (∼10 -6 M). Thus, a well known AOT RM system: benzene/AOT/water has been used in order to gain insights, for the first time, on how the RMs' formation can affect the C343 spectroscopic behavior. Dissolved in pure benzene C343 exists as a dimer since the intermolecular H-bond interactions are very strong in this solvent. When introduced to the AOT RMs, C343 resides in the RMs' interface and, at low occupation number the probability of finding more than one C343 molecule is reduced and only C343 monomer species is detected. From the spectral changes it was possible to determine the critical micelle concentration at W 0 = 0 and 10 and the C343 partition constants between two pseudophases. In summary, in this work we have shown how the spectroscopic behavior of C343 is dramatically altered because of the partition of the dye to the AOT RMs' interfaces.

Competition between collapse and breakup in nanometer-sized thin rings using molecular dynamics and continuum modeling Nguyen, Trung Dac; Fuentes-Cabrera, Miguel; Fowlkes, Jason D.; Diez, Javier Alberto; González, Alejandro G.; Kondic, Lou; Rack, Philip D. We consider nanometer-sized fluid annuli (rings) deposited on a solid substrate and ask whether these rings break up into droplets due to the instability of Rayleigh-Plateau-type modified by the presence of the substrate, or collapse to a central drop due to the presence of azimuthal curvature. The analysis is carried out by a combination of atomistic molecular dynamics simulations and a continuum model based on a long-wave limit of Navier-Stokes equations. We find consistent results between the two approaches, and demonstrate characteristic dimension regimes which dictate the assembly dynamics.

ABA says NO to UV-B: A universal response? Tossi, Vanesa Eleonora; Cassia, Raul Oscar; Bruzzone, Santina; Zocchi, Elena; Lamattina, Lorenzo Abscisic acid (ABA) signaling pathways have been widely characterized in plants, whereas the function of ABA in animals is less well understood. However, recent advances show ABA production by a wide range of lower animals and higher mammals. This enables a new evaluation of ABA signaling pathways in different organisms in response to common environmental stress, such as ultraviolet (UV)-B. In this opinion article, we propose that the induction of common signaling components, such as ABA, nitric oxide (NO) and Ca2+, in plant and animal cells in response to high doses of UV-B, suggests that the evolution of a general mechanism activated by UV-B is conserved in divergent multicellular organisms challenged by a changing common environment. © 2012 Elsevier Ltd.

The effect of UV-C in combination with H2O2 treatments on microbial response and quality parameters of fresh cut pear discs Schenk, Marcela Liliana; García Loredo, Analía; Raffellini, Silvia Monica; Alzamora, Stella Maris; Guerrero, Sandra N. The response of Escherichia coli ATCC 11229, Listeria innocua ATCC 33090 and Zygosaccharomyces bailii NRRL 7256 in fresh-cut pear to simultaneous and serial combined treatments involving H 2O 2 immersion (3% w/v; pH 3.0; 25°C; 2.0 or 5.0min) and UV-C exposure (7.5min; 3.7kJm -2) was investigated. For selected treatments, native flora, sensory and colour changes were also evaluated. E. coli and L. innocua were more sensitive than Z. bailii. Serial H 2O 2/UV-C treatments were more effective than the simultaneous arrangement. The single effect of UV-C was enhanced by the combination with 5min H 2O 2, hence avoiding the recovery of the surviving population. The combined treatment kept optimal microbial stability and exhibited more luminosity than the single UV-C treatment. Texture profile analysis conducted using a trained panel showed that H 2O 2/UV-C processed pear discs were perceived with significantly less hardness and fracturability but as juicy as untreated discs. Consumers found them pleasant.

Honra, fama y ejemplaridad en el Poema de Alfonso Onceno Janin, Erica Noemi La hipótesis que se sostiene en este estudio es que, mediante el uso particular que hay en el Poema de Alfonso Onceno, en relación a los poemas épicos de origen castellano del siglo anterior, de los conceptos de “honor”, “honra” y “fama”, el autor busca hacer de Alfonso un rey ejemplar y promover el ideal de reconquista; L’hypothèse proposée dans cette étude est que, par l'usage particulier que le Poema de Alfonso Onceno fait des notions de “honor”, “honra” et “fama” par rapport aux poèmes épiques d’origine castillane du siècle antérieur, l'auteur veut faire d'Alphonse un roi exemplaire et promouvoir l'idéal de reconquête

Francesc Fábregas i Pujadas autor del primer relevamiento de la estancia jesuítica de San Ignacio de Calamuchita en Córdoba Page, Carlos Alberto; Schavelzon Chavin, Daniel Gaston La representación artística de las estancias jesuíticas de Córdoba fue una labor iniciada a principios del siglo XX que contó con innumerables obras realizadas en todas las técnicas y por varios autores, especialmente arquitectos. En el presente trabajo se propone dar a conocer el autor de una serie de bocetos que representan las ruinas de la estancia jesuítica de San Ignacio de los Ejercicios de Córdoba y la reconstrucción artística de la misma que la logra a partir de un pormenorizado estudio documental y arqueológico. Hasta el momento se conocía esta obra, creyéndose un dibujo anónimo. Exponemos algunos antecedentes sobre las representaciones de similares edificios declarados por la UNESCO Patrimonio de la Humanidad, que no incluyeron San Ignacio, algunos datos biográficos del autor y la importancia de su obra al constituirse como el primer relevamiento arqueológico, e hipotética reconstrucción de esta importante estancia jesuítica.; The artistic representation of the estancias of Cordoba was a work begun in the early twentieth century that featured numerous works in all techniques and by several authors, especially architects. This paper intends to present the author of a series of sketches depicting the ruins of the Jesuit Mission of San Ignacio de Córdoba Exercises and artistic reconstruction achieved from a detailed, documental and archaeological study. So far this work was known, but believed an anonymous drawing. We present the background on similar representations of buildings declared an UNESCO World Heritage Site, which did not include San Ignacio, some biographical data of the author and the importance of his work to establish itself as the first archaeological survey, and hypothetical reconstruction of this important Jesuit stay.

"Quebracho" tannin derivative and boosters biocides for new antifouling formulations Bellotti, Natalia; Deya, Marta Cecilia; del Amo, Delia Beatriz; Romagnoli, Roberto The growth of fouling communities on ships' hulls causes economic losses due to increased fuel consumption and to the deterioration of the metallic substrate by corrosion. Antifouling paints are formulated to avoid the settlement of these organisms and may contain biocides as active compounds. The objective of this research was to evaluate the antifouling performance of paints formulated with a "quebracho" tannin derivative (zinc "tannate") and "boosters" (secondary biocides). The "boosters" used in this study were bismuth lactate, a zeolite exchanged with silver cations, and the same zeolite modified with silver chloride. Bioassays with "boosters" solutions were carried out employing Artemia persimilis. Soluble matrix antifouling paints were formulated and their action was assessed in a natural sea water environment. Results showed that the bismuth lactate resulted in a coating with almost triple service life of the antifouling paints with zinc "tannate." Paints formulated with the silver composites behaved slightly better than the control paint.

Benzyl 3-[(E)-(furan-2-yl)methylidene]-2-methyldithiocarbazate Dey, Benu K.; Suarez, Sebastian; Ganguly, Biplab; Doctorovich, Fabio; Roy, Tapashi G. In the title compound, C14H14N2OS 2, the furan ring exhibits rotational disorder over two orientations, with an occupancy ratio of 0.508 (7):0.492 (7). The furan and phenyl rings form dihedral angles of 8.2 (6) (major occupancy component), 14.8 (6) (minor occupancy component) and 73.65 (9)°, respectively, with the central residue (C4N2S2), indicating a twisted conformation for the molecule. The methyl group and the thione S atom are syn and the conformation about the imine bond is E. In the crystal, C - H⋯π interactions involving the phenyl ring are observed.

Índice de reflectancia solar de revestimientos verticales: potencial para la mitigación de la isla de calor urbana; Solar reflectance index of façade coatings: mitigation potential of urban heat islands Alchapar, Noelia Liliana; Correa Cantaloube, Erica Norma; Canton, Maria Alicia La condición artificial del medio urbano modifica el consumo de energía y el confort térmico. El incremento de las temperaturas de una ciudad en relación a las áreas periféricas conduce a la formación de una Isla de Calor Urbana. Es por ello, que trabajar sobre las propiedades termofísicas de los materiales (techos, pavimentos y fachadas) es una estrategia de mitigación viable para disminuir las temperaturas de una ciudad. El objetivo principal de éste trabajo es estudiar la capacidad de 80 revestimientos para fachadas disponibles regionalmente para mitigar los efectos negativos de la Isla deCalor Urbana, mediante la determinación del Índice de Reflectancia Solar (SRI). El material que posee el comportamiento más eficiente es el Acrílico Rulato Travertino fino marfil (SRI = 100%, Temp. Sup.= 35 ºC), mientras el más ineficiente es el Acrílico Llaneado fino gris plomo (SRI = 29%, Temp. Sup.= 74 ºC). No obstante existen alternativas intermedias que resultan del efecto combinado de la composición del material, su color y textura. Esta situación demuestra que es posible mitigar el efecto de isla de calor a partir de una adecuada selección de revestimientos verticales.; The artificial condition of an urban environment modifies energy consumption and thermal comfort. The higher temperatures in a city center in relation to peripheral areas, lead to the formation of an urban heat island. Therefore, working on the thermo-physical properties of materials (roofs, floors and facades) is a feasible mitigation strategy to reduce the temperature of a city. The main objective of this project is to study the capacity of 80 regionally available façade coatings to mitigate the negative effects of the urban heat island by determining the Solar Reflectance Index (SRI). The material that had the most efficient behavior was Travertine Rulato Acrylic fine ivory (SRI = 100%, Temp. Sup = 35 ºC), whereas the most inefficient was the fine dark gray Llaneado Acrylic (SRI = 29%, Temp. Sup = 74 ºC). There are also intermediate options that result from the combined effect of the material composition, color and texture. This situation shows that it is possible to mitigate the heat island effect by using the appropriate selection of vertical cladding.

Remarks on some scale worms (Polychaeta, Polynoidae) from the Southwest Atlantic with notes on the genus Eucranta Malmgren, 1866, and description of a new Harmothoe species Barnich, Ruth; Orensanz, Jose Maria; Fiege, Dieter In a collection of polychaetes from the Southwest Atlantic, off the Argentinian coast, ten scale worm species of the family Polynoidae were found. The following nine species are already known to science and their synonymy, diagnostic characters, and distribution are given together with remarks on taxonomy and geographical distribution: Eucranta mollis (McIntosh, 1876), Eucranta notialis Monro, 1936, Harmothoe exanthema (Grube, 1858), Harmothoe magellanica (McIntosh, 1885), Polyeunoa laevis McIntosh, 1885, Halosydna patagonica Kinberg, 1856, Halosydnella australis (Kinberg, 1856), Lepidasthenia esbelta Amaral and Nonato, 1982 and Showapolynoe marmorata (Hartmann-Schröder, 1965) n. comb. Additionally, a new Harmothoe species was discovered and is described in detail. Differentiating characters of the new species and Harmothoe ciliata Monro, 1936 from the Magellan region are discussed. Since two species of Eucranta Malmgren, 1866 out of four known worldwide occur in the Southwest Atlantic and since the genus has never been revised in the past, we discuss the distinguishing characters of the species and present a synoptic table. Furthermore, we raise two subspecies to species level, i. e. Eucranta villosa notialis Monro, 1936 to E. notialis Monro, 1936 and Harmothoe brevipalpa ciliata Monro, 1936 to H. ciliata Monro, 1936. Two new junior synonyms are also recognised: Harmothoe fimbriata Hartmann-Schröder, 1965 is referred to H. ciliata Monro, 1936 and Halosydna brasiliensis Kinberg, 1857 to Halosydnella australis (Kinberg, 1856). An identification key is given to all species found in the considered area.

Historia de la vegetación de las llanuras costeras de la Bahía Samborombón (35° S), Argentina, desde 7800 14C años; Vegetation history of the coastal plains from Samborombon Bay (35.5° S), Argentina, since 7800 14C years Vilanova, Isabel; Prieto, Aldo Raul El análisis palinológico de una sucesión sedimentaria expuesta en la margen derecha del Río Salado (35° 55? S - 57° 53? O), a 30 km de la costa actual de la Bahía Samborombón, permitió reconstruir la historia de la vegetación del centro de la bahía desde c. 7800 14C años. Los resultados revelan el desarrollo de diferentes comunidades vegetales: una vegetación halófita de marisma media entre 7800 y 7000 14C años AP, reemplazada, entre 7000 y 5400 14C años AP, por pastizales salobres de marisma baja en relación con el máximo transgresivo del nivel del mar; una comunidad halófita de transición a una marisma alta entre 5400 y 4300 14C años AP; y un pantano salobre y pastizales entre 4300 y 1700 14C años AP, con disminución progresiva de las condiciones estuáricas por el descenso del nivel del mar y la progradación de cordones litorales. Estos resultados junto con los registros del sur de la Bahía Samborombón y de la llanura Mar Chiquita (sudeste bonaerense) reflejan una vegetación regional similar entre 5400 y 4300 14C años AP, de pastizales halófitos de marisma baja y laguna costera; y una diferenciación local con posterioridad a 4300 14C años AP en relación con la geomorfología de cada área: un pantano salobre en la Bahía Samborombón, comunidades psammófitas al sur de ésta y vegetación halófita de marisma media en la llanura Mar Chiquita. Estos cambios revelan la sensibilidad de la respuesta de la vegetación a las fluctuaciones del nivel del mar y evolución geomorfológica.; The palynological analysis from a sedimentary sequence, outcropping on the right bank of the Salado River (35°55′S - 57°53′W), 30 km from the present coastline of the Samborombon Bay, allowed to reconstruct the vegetation history for the central bay area since c. 7800 14C years BP. Results indicate the development of different plant communities: middle-marsh halophytic vegetation between 7800 and 7000 14C years BP, replaced by low-marsh brackish grasses between 7000 and 5400 14C years BP in relation to sea-level highstand; a transitional high salt-marsh halophytic community, developed between 5400 and 4300 14C years BP; and, brackish marsh vegetation and grasslands between 4300 and 1700 14C years BP, with progressive decrease of estuarine conditions due to sea-level fall and litoral ridge progradation. These results along with those from the south of the Samborombon Bay and Mar Chiquita coastal plain (southeastern Buenos Aires province) showed a similar vegetation in the region, characterized by low-marsh and coastal lagoon halophytic grasses, developed between 5400 and 4300 14C years BP; and a local differentiation after 4300 14C years BP related to the geomorphology of each area: a brackish marsh vegetation in the Samborombon Bay, psammophytic communities at the south of the bay and middle salt-marsh halophytic communities in Mar Chiquita coastal plain. These changes reveal the sensitive response of vegetation from coastal marshes to the sea-level fluctuations and geomorphologic evolution.

Rodent diversity and habitat use in a protected area of Buenos Aires province Argentina; Diversidad y uso del hábitat por roedores en un área protegida de Buenos Aires, Argentina Gomez Villafañe, Isabel Elisa; Expósito, Yanina; San Martín, Alvaro; Picca, Pablo Ignacio; Busch, Maria El uso del hábitat de los roedores está asociado a variables ambientales, requerimientos específicos e interacciones biológicas. El objetivo de este estudio fue analizar el uso del macro y microhábitat y la variación espacial en la abundancia de pequeños roedores que habitan la Reserva Natural Otamendi, Argentina. Estudiamos la comunidad de roedores en 6 ambientes: bosque ribereño, talares, pastizales bajos, pastizal salino y 2 pastizales altos. Capturamos 153 individuos de Scapteromys aquaticus, Akodon azarae, Oxymycterus rufus, Oligoryzomys flavescens, Deltamys kempi y O. nigripes, con un esfuerzo de 3 636 trampas-noche. La riqueza de especies se mantiene mediante la presencia de diferentes hábitats que satisfacen los requerimientos específicos tanto de especies especialistas como especies generalistas, usando diferencialmente la reserva y formando comunidades de diferente composición en cada ambiente. Se observó un uso diferencial a escala del macrohábitat de todas las especies y una selectividad a escala del microhábitat en individuos de 2 especies. Este estudio muestra que la diversidad de ambientes en la reserva natural permite el mantenimiento de especies silvestres de pequeños roedores, confirmando el valor ecológico y de conservación de la reserva situada dentro de una región urbanizada.; Habitat use of rodents is associated to environmental variables, species requirements and biological interactions. The aim of this study was to analyse the macro and microhabitat use and spatial variation in the abundance of small wild rodents that inhabit Otamendi Natural Reserve, Argentina. We studied the rodent communities in 6 habitats: riparian forest, Celtis tala forest, lowland grassland, salt marsh and 2 highland grasslands. We captured a total of 153 individual of Scapteromys aquaticus, Akodon azarae, Oxymycterus rufus, Oligoryzomys flavescens, Deltamys kempi and O. nigripes, with a trapping effort of 3636 trap-nights. The species richness is maintained by the presence of different habitats that satisfy specific requirements from specialist and generalist species, using differentially the reserve and forming communities of different specific composition in each habitat. A differential macrohabitat use was observed by all species, and a certain level of selectivity at microhabitat scale was observed in individuals of 2 species. This study shows that the diversity of environments in the Otamendi Natural Reserve, which allows the maintenance of many wild species of small rodents; confirming the high ecological and conservational value of the reserves inside an urban region.

The Role of Ghrelin in Reward-Based Eating Perello, Mario; Zigman, Jeffrey M. The peptide hormone ghrelin acts in the central nervous system as a potent orexigenic signal. Not only is ghrelin recognized as playing an important role in feeding circuits traditionally thought of as affecting body weight homeostasis, but also an accumulating number of scientific studies have identified ghrelin as being a key regulator of reward-based, hedonic eating behaviors. In the current article, we review ghrelin's orexigenic actions, the evidence linking ghrelin to food reward behavior, potential mechanisms by which ghrelin mediates reward-based eating behavior, and those studies suggesting an obligatory role for ghrelin in the changed eating behaviors induced by stress.

El perímetro de una cuenca hídrica: su tratamiento objetivo en la definición de índices geomorfológicos Barrera, Daniel Florencio; Presutti, Miriam Elisabet; Rosatto, Héctor Gustavo Para relacionar la forma de una cuenca con su respuesta hidrológica se utilizan comúnmente índices de forma adimensionales que incluyen su área A y perímetro “suavizado”, como el coeficiente de compacidad de Gravelius. El perímetro de una cuenca depende de la resolución espacial en la que se lo determine. A fin de tornar objetivos dichos índices, proponemos reemplazar el borde de la cuenca por una poligonal de “segmentos básicos” Sb iguales y consecutivos, quedando acotado el perímetro una vez elegido dicho segmento. Además, proponemos que Sb sea función de Raiz(A), y los índices de forma resulten invariantes con respecto al área, permitiendo comparar objetivamente cuencas de distinto tamaño. Se varió la longitud de Sb para tres cuencas diferentes, de modo que las poligonales resultantes eliminan ciertos detalles pero preservan la forma de la cuenca. Se comprobó un buen ajuste lineal log-log entre Sb y la cantidad de segmentos en el perímetro, comprobando así que el borde de cuenca se comporta como un objeto fractal. Se analizó la variación del coeficiente de Gravelius en función de la longitud de Sb. Se propone usar Sb=1/5 Raiz(A) para determinar los índices de forma, y Sb=1/20 Raiz(A) para los índices que relacionan longitudes de ríos.; Dimensionless shape indexes are usually used to relate the form of a watershed with their hydrological re-sponse. These indexes relate the area A and the “smoothed” perimeter of a watershed, like Gravelius compact-ness coefficient. The perimeter depends on the spatial resolution on which is determined. In order to turn ob-jective the shape index, we propose to replace the watershed border by a polygonal of “basic segments” Sb equals and consecutive, so the perimeter is delimited once the segment have been chosen. Furthermore, we propose to relate Sb to SquareRoot(A), making these indexes invariant with respect to A and turning possible to make objective comparisons. The length of Sb was varied from a quarter to twentieth of , in three different basins. At these levels of length, the polygonal remove certain details but preserve the shape of the watershed. It has been proof a good fit in a lineal log-log relationship between the basic segment and the quantity of seg-ments in the perimeter, proving that the watershed border behave like a fractal object. Furthermore, the varia-tion of the Gravelius coefficient in function of the length of the basic segment was analyzed. We propose to use Sb=1/5SquareRoot(A) for shape indexes, and Sb=1/20 SquareRoot(A) for indexes relating river lengths.

Predominance of human lymphotropic T cell virus type 2 subtype b in Urban populations of Argentina Berini, Carolina Andrea; Eirin, Maria Emilia; Delfino, Cecilia María; Weissenbacher, Mercedes Crecencia; Biglione, Mirna Marcela Human T-lymphotropic virus subtype b (HTLV-2b) infection has been described among aborigines from Northern Argentina, while HTLV-2a has been described in an injecting drug user (IDU) from a Central region, similar to the situation in Spain, the United States, and Brazil. In this study, 22 of the 26 strains analyzed from blood donors and HIV-1+ individuals were HTLV-2b (84.6%) clustering with Amerindian references, while 4 HIV-1+ (15.4%) were HTLV-2a. HTLV-2a sequences were closely related to Brazilian references in contrast to the previous Argentinean IDU strain that clustered with Africans and Amerindians from North America. In summary, these findings show that HTLV-2b is the major strain circulating in an urban population of Argentina. HTLV-2a/b could have been introduced from endemic South American countries such as Brazil and because of contact with other populations such as IDUs from Europe despite its introduction due to the increasing internal migration of aborigines to large urban centers. Considering this results and recent data about the dissemination of HTLV-1 in residents of Buenos Aires city, new studies among non-at-risk groups for HTLV-1/2 infection should be performed. © Copyright 2012, Mary Ann Liebert, Inc. 2012.