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

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

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

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

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

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

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

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

DFT broken-symmetry exchange couplings calculation in a 1D chain of bridged iron basic carboxylates Alborés, Pablo; Rentschler, Eva DFT broken-symmetry calculations at the B3LYP level were carried out to evaluate the exchange coupling constants defined by the Heisenberg-Dirac-van Vleck spin Hamiltonian (HDvV), Ĥ = -2JŜaŜb, in a 1D chain of iron basic carboxylate cores [Fe3O(Piv)6(H2O)] bridged by dicyanamide, and two related trinuclear Fe3O moieties. The chain complex was modeled as two Fe3O units that preserve all features of the repetitive unit in the infinite real system. All geometries were taken from the crystallographic data previously reported. The obtained calculated values for the J constants are in good agreement with experimental results. The weak anti-ferromagnetic inter-Fe3O core interaction along the chain is also reasonably accounted by the calculations. This methodology appears as a useful tool in the theoretical evaluation of exchange coupling constants in 1D systems.

Stromal cell expression of caveolin-1 predicts outcome in breast cancer Sloan, Erica K.; Ciocca, Daniel Ramon; Pouliot, Normand; Natoli, Anthony; Restall, Christina; Henderson, Michael A.; Fanelli, Mariel Andrea; Cuello Carrión, Fernando Darío; Gago, Francisco E.; Anderson, Robin L. Caveolin-1 has been linked to tumor progression and clinical outcome in breast cancer, but a clear resolution of its role as a prognostic marker is lacking. We assessed caveolin-1 levels in normal breast tissue and two breast cancer cohorts for which outcome data were available. We found that caveolin-1 was not expressed in normal breast luminal epithelium but was present in the epithelial compartment of some tumors. We found no association between caveolin-1 expression in the epithelial compartment and clinical outcome. However, high levels of caveolin-1 in the stromal tissue surrounding the tumor, rather than within tumor cells, associated strongly with reduced metastasis and improved survival (P < 0.0001). The onset of mammary tumors driven by Her2/neu overexpression was accelerated in mice lacking caveolin-1, thereby supporting the observation that the presence of caveolin-1 in the tumor microenvironment modulates tumor development. These studies suggest that stromal caveolin-1 expression may be a potential therapeutic target and a valuable prognostic indicator of breast cancer progression.

Las expectativas de los débiles. Protesta obrera y política en Tucumán, durante el verano de 1932 Fernandez de Ullivarri, Maria Este trabajo intenta analizar los procesos de lucha obrera en la provincia de Tucumán, al norte de la Argentina, durante los primeros meses del año 1932 y sus vínculos con los sucesos políticos provinciales. Para ello nos detendremos en una coyuntura de protesta obrera en un momento de crisis política, social y económica, donde la represión fue un componente importante de las relaciones entre el Estado y la sociedad. De esta forma, una huelga violenta en 1932, el contexto político e institucional particular en el que se inscribió, los usos que de ella hicieron los políticos y los sentidos otorgados a ella por los trabajadores pretenden ser el nudo central de este artículo.; Abstract: This paper attempts to analyze the processes of labor struggle in the province of Tucuman, northern Argentina, during the first months of 1932 and its links with the local political events. To do this we’ll examine a period of protest at a time of political, social and economic crisis, where repression was an important component of relations between state and society. In this way, a violent strike in 1932, the particular political and institutional context in which it was entered, the uses made of it by politicians and the senses given to it by workers are the main topics of this article

Carbohydrate-binding proteins: dissecting ligand structures through solvent environment occupancy Gauto, Diego Fernando; Di Lella, Santiago; Guardia, Carlos Manuel Alberto; Estrin, Dario Ariel; Marti, Marcelo Adrian Formation of protein ligand complexes is a fundamental phenomenon in biochemistry. During the process, significant solvent reorganization is produced along the contact surface and many water molecules strongly bound to the protein's ligand binding site must be displaced. Both the thermodynamics and kinetics of this process are complex and a clear understanding at the microscopic level has been not achieved so far. Special attention has been paid to the structure of water molecules on carbohydrate recognition sites of various proteins, and many studies support the idea that displacement of these water molecules should have a crucial effect on the binding free energy. Molecular dynamics (MD) simulations in explicit water solvent is a very promising approach for this type of studies. Using MD simulations combined with statistical mechanics analysis, thermodynamic properties of these water molecules can be computed and analyzed in a comparative view. Using this idea, we developed a set of analysis tools to link solvation with ligand binding in a key carbohydrate binding protein, human galectin-1 (hGal-1). Specifically, we defined water sites (WS) in terms of the thermodynamic properties of water molecules strongly bound to protein surfaces. In the present work, we selected a group of proteins whose ligand bound complexes have been already structurally characterized in order to extend the analysis of the role of the surface associated water molecules in the ligand binding and recognition process. The selected proteins are concanavalin-A (Con-A), galectin-3 (Gal-3), cyclophilin-A (Cyp-A), and two modules CBM40 and CBM32 of the multimodular bacterial sialidase. Our results show that the probability of finding water molecules inside the WS, p(V), with respect to the bulk density is directly correlated to the likeliness of finding an hydroxyl group of the ligand in the protein-ligand complex. This information can be used to analyze in detail the solvation structure of the carbohydrate recognition domain (CRD) and its relation to the possible protein ligand complexes and suggests addition of OH-containing functional groups to displace water from high p(V) WS to enhance drugs, specially glycomimetic-drugs, protein affinity, and/or specificity.

Influence of process variables of ECF Ep bleaching stage; Influência das variáveis de processo na etapa Ep do branqueamento ECF Mendez, Claudia Marcela; Area, Maria Cristina Kraft pulp bleaching is difficult, since residual lignin does not dissolve in a single stage with chlorinated compound application. Multiple stages using a significant amount of reagents are necessary to obtain high levels of brightness. The inclusion of hydrogen
peroxide in the last alkaline stage of the ECF (Elemental Chlorine Free) bleaching of kraft pulps is at present common practice, as it increases brightness and its stability, besides preserving pulp viscosity and improving the quality of the effluents. The objective of this work consisted in evaluating the process variables of the Ep stage of a pine kraft pulp bleaching process. A fractionated factorial design was initially applied, using as variables the temperature (72ºC – 90ºC), the initial pH (10.5 and 11.5), the initial concentration of H2O2 (0.2% and 0.4% on o.d. pulp – oven-dry pulp), and two types of chelants (DTPA and DTPMPA) at 0.025% on o.d. pulp. A laboratory bleaching was simulated at 10% consistency and 1h residence time. Temperature, initial concentration of H2O2, and pH were the significant variables for the optical pulp properties. An experimental Central Composite Design (CCD) of two factors at five levels was applied with the first two factors, totalling 11 experiments (8 + 3 central point
repetitions for pure error determination), a fixed NaOH (% on o.d. pulp) / H2O2 (% on o.d. pulp) ratio equal to 3 having been establishing to maintain the alkalinity. Bleaching processes at different times (5, 10, 20, 45, 90, 180, and 240 minutes) were carried out for each of these experiments, and brightness values higher than 89% ISO were obtained at initial concentrations of 0.25% on o.d. pulp and 0.39% on o.d. pulp of H2O2 at 81ºC, and with 0.35% on o.d. pulp of initial H2O2 at 90ºC and 72ºC, at 180 minutes’ bleaching. The initial concentration of hydrogen peroxide was significant at the different reaction times. At 45 minutes’ reaction (as usually put into practice by the industry for this stage), the maximum brightness values were obtained under the following conditions: T = 81ºC at 0.39% on o.d. pulp of initial H2O2, and T = 90ºC at 0.35% o.d. pulp of initial H2O2. However, it should be observed that the pulp submitted to these last conditions presented higher brightness reversion.; As polpas kraft são de branqueamento difícil, pois que a lignina residual não se dissolve em um só estágio de aplicação de compostos clorados, sendo necessários múltiplos estágios e uma quantidade expressiva de reagentes para a obtenção de altos níveis de alvura. A inclusão de peróxido de hidrogênio no último estágio alcalino do branqueamento ECF (Elemental Chlorine Free) de polpas kraft é atualmente uma prática comum, pois incrementa a alvura e sua stabilidade, além de preservar a viscosidade das polpas e melhorar a qualidade dos efluentes. O presente trabalho consistiu em avaliar as variáveis de processo do estágio Ep de uma polpa kraft de pinho. Foi inicialmente aplicado um desenho fatorial fracionado, utilizando-se como variáveis a temperatura (72ºC – 90ºC), o pH inicial (10,5 e 11,5), a concentração inicial de H2 O2 (0,2% e 0,4% sobre polpa a.s. – absolutamente seca) e dois tipos de quelantes (DTPA e DTPMPA) a 0,025% sobre polpa a.s. Foi simulado branqueamento em laboratório com consistencia de 10% e com tempo de residência de 1h. As variáveis significativas para as propriedades ópticas das polpas foram: a temperatura, a concentração inicial de H2 O2 e o pH. Com os primeiros dois fatores foi aplicado um desenho experimental tipo central composto (Central Composite Design: CCD) de dois fatores e cinco níveis, com um total de 11 experimentos (8 + 3 repetições do ponto central para a determinação do erro puro), sendo estabelecida uma relação NaOH (% sobre polpa a.s.) / H2 O2 (% sobre polpa a.s.) fixa e igual a 3, para manutenção da alcalinidade. Para cada uma destas experiências foram realizados branqueamentos com tempos diferentes (5, 10, 20, 45, 90, 180 e 240 minutos). Foram obtidos valores de alvura superiores a 89% ISO com concentrações iniciais de 0,25% sobre polpa a.s. e 0,39% sobre polpa a.s. de H2 O2 a 81ºC, e com 0,35% sobre polpa a.s. de H2 O2 inicial a 90ºC e 72ºC, com 180 minutos de branqueamento. A concentração inicial de peróxido de hidrogênio foi significativa aos diferentes tempos de reação. Aos 45 minutos de reação (o normalmente praticado na indústria para esse estágio), as alvuras máximas foram obtidas com as seguintes condições: T = 81ºC com 0,39% sobre polpa as de H2 O2 inicial e T = 90ºC com 0,35% sobre polpa a.s. de H2 O2 inicial. De se observar, contudo, que a polpa submetida a essas últimas condições apresentou maior reversão de alvura.

Chemistry and in vitro antioxidant activity of volatile oil and oleoresins of black pepper (Piper nigrum) Kapoor, I. P. S.; Singh, Bandana; Singh, Gurdip; Schuff, Carola; Perotti, Marina Elvira; Catalan, Cesar Atilio Nazareno Essential oil and oleoresins (ethanol and ethyl acetate) of Piper nigrum were extracted by using Clevenger and Soxhlet apparatus, respectively. GC-MS analysis of pepper essential oil showed the presence of 54 components representing about 96.6% of the total weight. β-Caryophylline (29.9%) was found as the major component along with limonene (13.2%), β-pinene (7.9%), sabinene (5.9%), and several other minor components. The major component of both ethanol and ethyl acetate oleoresins was found to contain piperine (63.9 and 39.0%), with many other components in lesser amounts. The antioxidant activities of essential oil and oleoresins were evaluated against mustard oil by peroxide, p-anisidine, and thiobarbituric acid. Both the oil and oleoresins showed strong antioxidant activity in comparison with butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) but lower than that of propyl gállate (PG). In addition, their inhibitory action by FTC method, scavenging capacity by DPPH (2,2′-diphenyl-1 -picrylhydrazy1 radical), and reducing power were also determined, proving the strong antioxidant capacity of both the essential oil and oleoresins of pepper.

The local and observed photochemical reaction rates revisited Alfano, Orlando Mario; Irazoqui, Horacio Antonio; Cassano, Alberto Enrique In a broad sense, photochemical reactions proceed through pathways involving several reaction steps. The initiation step is the absorption of energy both by the reactant or sensitizer molecules and in some cases, by the catalyst, leading to intermediate products that ultimately give rise to stable end products. Preferably, the reaction rate expression is derived from a proposed mechanism together with sound simplifying assumptions; otherwise, it may be adopted on an empirical basis. Under a kinetic control regime, the rate expression thus obtained depends on the local rate of photon absorption according to a power law whose exponent very often ranges from one half to unity. The kinetic expression should be valid at every point of the reactor volume. However, due to radiation attenuation in an absorbing and/or scattering medium, the value of the photon absorption rate is always a function of the spatial position. Therefore, the overall photochemical reaction rate will not be uniform throughout the entire reaction zone, and the distinction between local and volume average photochemical reaction rates becomes mandatory. Experimental values of reaction rates obtained from concentration measurements performed in well-mixed reaction cells are, necessarily, average values. Consequently, for validation purposes, experimental results from these cells must be compared with volume averages of the mechanistically or empirically derived local reaction rate expressions. In this work it is shown that unless the rate is first order with respect to the photon absorption rate or the attenuation in the absorbing and/or scattering medium is kept very low, when the averaging operation is not performed, significant errors may be expected.

Enantioselective esterification of racemic ibuprofen with ethanol as reactant and solvent catalyzed by immobilized lipase: experimental and molecular modeling aspects Foresti, María Laura; Galle, Marianela Edith; Ferreira, Maria Lujan; Briand, Laura Estefania In the last years enantioselective esterification of racemic ibuprofen performed in organic solvent media and catalyzed by lipases has been proposed as an effective way to increase the concentration of unesterified S-ibuprofen in the racemic mixture. In this contribution, a system free of organic solvent is proposed as a novel eco-friendly medium to perform the enantioselective enzymatic esterification of (R,S)-ibuprofen. Results showed that the reaction in excess of the esterifying alcohol in a system free of organic solvent is possible if the proper conditions are set. The effects of the amount of water present in the reaction medium, the volume of the alcohol used as acyl acceptor, the enzyme loading, and the reaction temperature, were alternatively analyzed in terms of the (conversion of ibuprofen towards the ester) reaction yield and enantiomeric excess achieved. Alcohol concentration showed to be determinant for both biocatalyst activity and enantioselectivity. The initial water content of reaction medium also showed to be a key parameter in a compromise between biocatalyst hydration and ester hydrolysis. By using 1 ml of ethanol as esterifying reagent, with an initial optimal water content of 4.8% v/v, at 45 °C, and with 160 mg of Novozym a total conversion of 62% and an enantiomeric excess of substrate of 54% were obtained in 72 hours of reaction.

Nucleotide polymorphism in the drought responsive gene Asr2 in wild populations of tomato Giombini, Mariano Ignacio; Frankel, Nicolás; Iusem, Norberto Daniel; Hasson, Esteban Ruben The Asr gene family (named after abscicic acid [ABA], stress, ripening), exclusively present in plant genomes, is involved in transcriptional regulation. Its members are up-regulated in roots and leaves of water- or salt-stressed plants. In previous work, evidence of adaptive evolution (as inferred from synonymous and nonsynonymous divergence rates) has been reported for Asr2 in Solanum chilense and S. arcanum, two species dwelling in habitats with different precipitation regimes. In this paper we investigate patterns of intraspecific nucleotide variation in Asr2 and the unlinked locus CT114 in S. chilense and S. arcanum. The extent of nucleotide diversity in Asr2 differed between species in more than one order of magnitude. In both species we detected evidence of non-neutral evolution, which may be ascribed to different selective regimes, potentially associated to unique climatic features, or, alternatively, to demographic events. The results are discussed in the light of demographic and selective hypotheses.

Subjetividad, potencia y política: Reflexiones a partir de Medios sin fin de Giorgio Agamben Peller, Mariela Este ensayo realiza algunas reflexiones a partir de Medios sin fin. Notas sobre la política de Giorgio Agamben (1996). En ese libro y en su obra en general, el filósofo se propone repensar todas las categorías de la tradición política occidental. Desde ese punto de partida, el presente ensayo examina las posibilidades que plantea Agamben para pensar la política venidera en la situación actual. En primer lugar, se presenta la lectura de Agamben de las condiciones políticas contemporáneas. Luego se analizan tres ejes fundamentales de su filosofía que nos permiten pensar sobre el futuro de la política: 1) el problema de las identidades y de la subjetividad; 2) la posibilidad de una lógica no instrumental de la política; 3) la problemática del pensamiento. Por último, el ensayo se refiere al lugar central que ocupa la categoría de potencia en la teoría de Agamben y a las posibilidades de pensar nuevas formas comunitarias y políticas que esa noción otorga.; This essay thinks about Means without end. Notes on politics of Giorgio Agamben (1996). In this book and in his work in general, the philosopher proposes to rethink all the categories of the political western tradition. Departing from this point, the present essay examines the possibilities that Agamben postulates to think politics in the actual moment. First, it presents Agamben’s reading of the political contemporary conditions. Then, it analyzes three fundamental points of that author’s philosophy that allow us to think on the future of politics: 1) the problem of identities and subjectivity; 2) the possibility of a not instrumental logic of politics; 3) the problematic of the thought. Finally, the essay refers to the central place that occupies the category of potency in Agamben’s theory and to the possibilities that this notion open, considering a new community and renewed political forms.

La Marca-Ciudad como herramienta de promoción turística: ¿Instrumento de inserción nacional e internacional? Calvento, Mariana; Colombo, Sandra Silvia La presente investigación analiza la Marca-Ciudad, una nueva herramienta implementada como instrumento de inserción nacional internacional por algunos gobiernos locales. La modificación en las funciones y los desafíos que enfrentan los gobiernos subnacionales, conjuntamente con las transformaciones en las lógicas empresariales, constituyeron un escenario en el cual la estrategia Marca-Ciudad comenzó a considerarse como una herramienta alternativa para alcanzar el desarrollo conjunto de ciudades y empresas a través de la promoción del turismo y el posicionamiento de la ciudad. En ese sentido, el trabajo indaga sobre los procesos de creación e implementación de Marca-Ciudad en la Argentina, particularmente analizando municipios pertenecientes a la Provincia de Buenos Aires, tomando como casos de estudios a Tandil y de Villa Gesell, entre los años 2003-2007. De esta manera, por medio de casos concretos se profundiza sobre las características, fortalezas y debilidades que adquieren los procesos en ciudades argentinas, a través de tres planos de análisis: la creación, la implementación y la comparación de la Marca-Ciudad en los casos de estudio.

Cadmium and Zinc Biosorption by Macrocystis Pyrifera: Changes in the Biomass Plaza Cazón, Josefina del Carmen; Guibal, Eric; Taulemesse, Jean Marie; Viera, Marisa Rosana; Donati, Edgardo Ruben Macrocystis pyrifera was used for the recovery of Zn2+ and Cd2+ from slightly acidic solutions (i.e., pH 4). Sorption isotherms were obtained from mono- and bi-component solutions. For the study of metal desorption, EDTA, HNO3 and Ca(NO3)2 were used as eluents. Metal release (Ca2+, Mg2+, K+ and Na+) was monitored in order to evaluate ion exchange mechanisms. After metal sorption/desorption steps the sorbent was characterized using SEM-EDAX analysis. SEM-EDAX analysis also allowed identifying the presence of elements such as Si, Al, Co, Ag, S, P, and Fe in the cell wall. Zinc desorption was almost complete when using 0.1 M nitric acid solution and the sorbent was not significantly damaged by the acidic treatment. Cadmium was completely removed from loaded sorbent when using EDTA, but at the expense of a partial degradation of the biomass as evidenced by the decrease in the intensity of the C and O peaks (SEM-EDAX).