Sindicador de canales de noticias

Abundancias químicas y parámetros físicos de estrellas con planetas

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Abundancias químicas y parámetros físicos de estrellas con planetas Vendemmia, Estefania Beatriz; Pintado, Olga Ines; Gomez, Mercedes Nieves La elevada metalicidad en las estrellas con planetas podría favorecer la formación de planetas ya sea a través del modelo de acreción de núcleos o de la inestabilidad del disco. Debido a esto hay un gran interés en estudiar las atmósferas de estrellas que albergan planetas. Presentamos resultados del estudio de atmósferas de este tipo de estrellas, analizando abundancias de algunos elementos químicos relevantes y parámetros estelares tales como temperatura efectiva, gravedad superficial y velocidad de microturbulencia. Estos objetos estudiados, con tipos espectrales no estrictamente solares, fueron observados con el espectrógrafo EBASIM de CASLEO.; The high metallicity in stars with planets could favor the formation of planets either through the model of nuclei accretion or the instability of the disk. Because of this there is great interest in studying the atmospheres of stars that host planets. We present results of the study of atmospheres of this type of stars, analyzing abundances of some relevant chemical elements and stellar parameters such as effective temperature, surface gravity and microturbulence velocity. These objects studied, with spectral types not strictly solar, were observed with the CASLEO EBASIM spectrograph.

Screening parameters for the relativistic hydrogenic model

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Screening parameters for the relativistic hydrogenic model Lanzini, Fernando Gabriel; Di Rocco, Hector Omar We present a Relativistic Screened Hydrogenic Model (RSHM) where the screening parameters depend on the variables ( ) nl j, and the parameters ( ) Z N. These screening parameters were derived theoretically in a neat form with no use of experimental values nor numerical values from self-consistent codes. The results of the model compare favorably with those obtained by using more sophisticated approaches. For the interested reader, a copy of our code can be requested from the corresponding author.

El dólar no está a salvo

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El dólar no está a salvo Rapoport, Mario Daniel El drama que azota a Grecia y que sacude al euro y los cambios más recientes en las corrientes del comercio mundial exigen replantear, entre otras cuestiones, el futuro del dólar como moneda clave del sistema monetario del planeta. El caso de Grecia y la actual crisis del euro no deben hacernos quitar la mirada del dólar, la moneda que domina la economía mundial. Quizás entendiendo su papel y funciones podemos comprender mejor los problemas del euro que en algún momento se colocó como una divisa alternativa. Sin duda, la cuestión del euro pasa por la diferencia de los espacios políticos: la zona euro constituye un conjunto de países unidos por la moneda pero separados en cuanto a sus regímenes políticos y sociales y al estado de sus economías. Los EE.UU. no tienen ese problema, pese a lo cual el dólar contiene elementos que no impiden que pueda entrar en crisis.

Entre la Historia y la ficción. Algunos temas en Yo el Supremo de Augusto Roa Bastos

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Entre la Historia y la ficción. Algunos temas en Yo el Supremo de Augusto Roa Bastos Peña Arroyave, Alejandro El escrito presenta un acercamiento a la novela Yo el supremo del escritor paraguayo Augusto Roa Bastos. En un primer momento se toma como punto de partida la filiación de la narrativa de Roa Bastos con el humanismo del existencialismo del siglo XX, entendiendo su labor de escritor en compromiso con el dolor humano y con su propio tiempo. A la luz de esto, en los siguientes momentos del escrito se abordan problemas tales como la obsesión con el poder absoluto y la anulación de la otredad caracterizada por un discurso en el que las distintas voces son absorbidas en el monólogo del dictador y que por ello mismo quedan deformadas. Desde dicha deformación surge sin embargo una particular relación entre la ficción y la narración histórica. Con ello se indicaría, desde el punto de vista de la novela histórica, que la Historia no está exenta de la ficción, y que sin duda ésta tiene mucho que iluminar acerca de la Historia.; The writing there presents an approximation to the novel I, the Supreme one of the Paraguayan writer Augusto Roa Bastos. At first takes as its starting point the parentage of the narrative of Roa Bastos with humanism of existentialism of the twentieth century, understanding his writing in commitment to human pain and his own time. From this, at the following times of writing problems such as obsession with absolute power and cancellation of otherness characterized by a speech in which different voices are absorbed in the monologue of the dictator are addressed and therefore thereof are deformed. From the above mentioned deformation a particular relation arises nevertheless between the fiction and the historical novel. Thereby would indicate that, from the point of view of the historical novel, the History is not exempt from the fiction, and that undoubtedly this one has great that to illuminate brings over of the History.

El científico cultural, ese artefacto sofisticado. Warburg entre Burckhardt y Nietzsche

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El científico cultural, ese artefacto sofisticado. Warburg entre Burckhardt y Nietzsche Losiggio, Daniela El presente artículo se ocupa de analizar la relación entre obra/pensamiento y vida, a partir de las anotaciones para el seminario sobre Jacob Burckhardt dictado por Aby Warburg en la Universidad de Hamburgo en el ciclo 1926-1927. Las personalidades de Burckhardt y de Nietzsche, tomados como "sismógrafos" captadores de "ondas mnémicas", sirven a Warburg para elucidar ese pasaje, así como para establecer las fuerzas que definen su propio pensamiento.

Forms of vitality play and symbolic play during the third year of life

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Forms of vitality play and symbolic play during the third year of life Español, Silvia Ana; Bordoni, Mariana Gabriela; Martínez, Mauricio; Camarasa, Rosario; Carretero Perez, Soledad This article focuses on the development of forms of vitality play, a recently described type of play, and links it to the development of symbolic play, one of the most studied types of play in developmental psychology. Two adult–infant dyads were videotaped longitudinally during in-house free play meetings every 15 days during the third year of life. Convergence technique was applied in order to accelerate the longitudinal study. A total of 17 h 48 min were registered in 28 sessions. An observational code with categories of forms of vitality play (a non-figurative play frame in which child and adult play together with the dynamics of their own movements and sounds in a repetition–variation form), symbolic play, and categories of combined patterns of both types of play was applied. The rate of each play was calculated for different age periods. Forms of vitality play is present at a constant rate during the third year of life. Symbolic play flourishes during this period. Combined play patterns are not the most frequent but are present from the beginning to the end of the third year. We suggestthat FoVP favours intimate and intersubjective experiences essential to the understanding and the development ofthe interpersonal world;thatit can be thought of as a good runway for the development of symbolic play; and that it prepares the child to participate in the temporal arts that belong to his culture.

Experimental and analytical study of the motion of a sphere falling along an inclined plane in still water

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Experimental and analytical study of the motion of a sphere falling along an inclined plane in still water Martino, Román Gustavo; Paterson, Agnes; Piva, Marcelo Fabian In this work, the transient regime of motion of a sphere, that falls along an inclined smooth plane, submerged in still water, is studied experimentally and analytically. Several experiments were performed, with spheres of different diameters and densities, and two slope angles. The measurements show that the motion of the sphere presents two well defined stages: a transitional regime, where the sphere rapidly accelerates from rest, and an asymptotic regime, where the sphere moves with constant velocity. Closed expressions, for the position and velocity of the sphere as functions of time, are obtained by direct integration of the motion equations. This theoretical analysis is based on the empirical correlation for the drag coefficient as a function of the Reynolds number of the sphere, that was proposed by Chhabra and Ferreira [2] for the experimental data set of Jan and Chen [1]. The analytical solution shows good agreement with experimental results, for a wide range of experimental conditions.

Phytophthora austrocedri elicitates changes in diterpene profile of austrocedrus chilensis

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Phytophthora austrocedri elicitates changes in diterpene profile of austrocedrus chilensis Olate, Verónica Rachel; Vélez, María Laura; Greslebin, Alina Gabriela; Schmeda Hirschmann, Guillermo The populations of the Andean Cupressaceae Austrocedrus chilensis have been severely affected by a disease caused by the phytopathogenic fungus Phytophthora austrocedri. A study was undertaken to disclose changes in the resin composition of P. austrocedri-infected individuals, including naturally infected and artificially inoculated trees, compared with healthy A. chilensis trees. GC-MS and 1H-NMR studies showed a clear differentiation among healthy and infected resins, with the diterpene isopimara-8(9),15-dien-19-ol as a relevant constituent in resins from infected trees. The effect of resin fractions from P. austrocedri infected trees on the pathogen was assessed by measuring the mycelial growth in agar plates. The most active fractions from resin obtained from infected trees inhibited fungal growth by nearly 50% at 1 mg/dish (35.37 μg/cm2). The main constituent in the active fractions were 18-hydroxymanool and the aldehyde torulosal. Both compounds are oxidation products of manool and can be a chemical response of the tree to the pathogen or be formed from the pathogen as a biotransformation product of manool by microbial oxidation. While the diterpene profiles from A. chilensis tree resins can easily differentiate healthy and P. austrocedri infected individuals, the possible conversion of manool to the antifungal derivatives 4 and 6 by the microorganism remains to be established.

Variaciones espaciales y temporales de la deriva litoral, SE de la Provincia de Buenos Aires, Argentina

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Variaciones espaciales y temporales de la deriva litoral, SE de la Provincia de Buenos Aires, Argentina; Spatial and temporal variations of the litoral drift, Southeastern Buenos Aires Province, Argentina Isla, Federico Ignacio El bloqueo de la deriva litoral provocó signifi cativos impactos en las costas de Mar del Plata y Necochea, Buenos Aires, Argentina. En algunos sectores, la construcción de espigones no dio los mismos resultados que tuvieron entre los años sesenta a ochenta. Se especula que la deriva litoral ha disminuido. Hubo varios intentos de estimar este transporte litoral, o al menos la magnitud de las olas y tormentas que son determinantes de ese transporte. La compilación de estimaciones dispersas sobre el tema confi rmó que la deriva potencial calculada a partir de datos de ola no se corresponde con la efectiva en relación a la disponibilidad de arena en el sistema litoral. Esta falta de arena ocurre donde se produjo un aumento en la frecuencia de corrientes rips por largo de playa.; The blocking of the longshore drift has caused signifi cant impacts along the Mar del Plata and Necochea coastline, Buenos Aires, Argentina. In certain sectors, groyne construction is not giving the same results they did in the sixties to eighties. It was speculated that potential longshore drift has diminished. Several attempts have tried to estimate this transport, or at least the magnitude of waves and storms that seem to have a signifi cant role with this transport. A compilation of scattered data about the subject confi rms a minimum drift amount of 100,000 m3/year. However, certain issues should be considered. The number of storms per year (locally called “sudestadas”) has a signifi cant weight in the northwards coastal transport. As wave statistics is completely dependent on the location where they are measured, wavebased models should be handled with much care. Groyne fi elds increase the density of rip currents and therefore are responsible for a reduction of the longshore transport. However, there are natural variations of the coastal dynamics and transport that are also explaining morphological changes that occurred during the Holocene.

Corpus, caro y anima en la concepción del hombre de Tertuliano

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Corpus, caro y anima en la concepción del hombre de Tertuliano Giacomone, Mariel En este trabajo abordamos la concepción del hombre de Tertuliano, pensador africano del siglo II, en el marco de su inserción en la tradición apologista de Justino e Ireneo. Al igual que ellos el cartaginés adopta una consideración positiva del cuerpo, más específicamente de la carne, como elemento constitutivo en la definición del hombre, pareciendo asumir, en ocasiones, la carga de la especificidad humana. Sin embargo, Tertuliano atiende a la noción de alma como un aspecto central de su esquema antropológico en un escrito que le dedica especialmente. En este sentido desarrollamos en el artículo los conceptos de corpus, caro y anima a la luz de la tensión respecto de lo que a veces indica una primacía de un aspecto por sobre el otro. A partir del análisis principalmente de la obra De anima y de algunas menciones al Libro II de Adversus Marcionem, concluimos que prevalece en Tertuliano una perspectiva unitaria sobre el hombre.; This paper deals with Tertullian’s conception of man in the context of the previous apologetic tradition. Such as Justin of Rome and Irenaeus of Lyons did before, Tertullian assumes a positive consideration of the human body –properly the flesh-. The author sometimes presents it as the primordial element of human definition. However, he also pays special attention to the soul as a fundamental aspect of human constitution. In order to identify whether one of these aspects prevails ontologically over the other in his anthropological thought, we first analyze the concepts of corpus, caro and anima developed by Tertullian in De anima. Then we will make some references to Adversus Marcionem. Finally our conclusion suggests that tertullian´s anthropological approach reflects a unitary conception of man which includes both the flesh and the soul.

Los cuerpos y las dictaduras: un acercamiento a la escritura de Cristina Peri Rossi

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Los cuerpos y las dictaduras: un acercamiento a la escritura de Cristina Peri Rossi Arnés, Laura Antonella La obra de la uruguaya Cristina Peri Rossi provee un material privilegiado al momento de analizar ciertas modulaciones que la cultura latinoamericana propone entre estética y política. Si se traza un arco entre Indicios pánicos (1970) y Desastres íntimos (1997), dos libros clave en su producción, es posible leer no sólo los modos en que la tematización de la dictadura ?tanto la militarizada como la dictadura política sobre los cuerpos sexuados ? establece un continuo en sus relatos sino, también, los modos en que la autora habilita una respuestapolítica y contracultural ? que pretende desarticular toda codificación hegemónica y denunciar las repeticiones de la Historia ? a partir de la erotización de la escritura.; The work of the Uruguayan Cristina Peri Rossi provides privileged material when analyzing certain modulations that Latin-American culture proposes between aesthetics and politics. If we draw an arch between Indicios pánicos (1970) and Desastres íntimos (1997), two key books in her production, it is possible to read not only certain manners in which the issue of dictatorships – both the militarized one and the political dictatorship on the sexed bodies – establishes a continuum in her texts but, also, the way in which the authoress enables a political and contracultural response – that tries to dismantle any hegemonic codification and to denounce the repetitions of History – starting on the erotization of the writing.

Disputas jurídico – políticas en torno a las expropiaciones de inmuebles rurales en la provincia de Chaco

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Disputas jurídico – políticas en torno a las expropiaciones de inmuebles rurales en la provincia de Chaco; Legal and political disputes over the expropriation of rural lands in the province of Chaco Barbetta, Pablo Nicolas Las organizaciones campesinas y de pequeños productores así como también indígenas despliegan una serie de acciones y estrategias, tanto judiciales como político administrativas, para frenar los procesos de exclusión por los que atraviesan como consecuencia de los procesos desatados por la hegemonía del modelo del agronegocio. En la provincia de Chaco, este activismo se reflejó en el resurgimiento, luego del proceso liguista, de múltiples organizaciones campesinas y de pequeños productores e indígenas, con el consecuente el despliegue de acciones de protesta y de resistencia. En este contexto de acorralamiento y expulsión de los pequeños productores y/o campesinos de la tierra es que nos interrogamos acerca de la expropiación como estrategia para lograr el acceso a la propiedad de la tierra. Así, el objetivo generalde este trabajo remite a analizar y comprender los procesos de expropiación de tierras, en tanto acción político –jurídica, para lograr el acceso a la propiedad de la tierra o su titularidad por parte de pequeños productores campesinos e indígenas en la provincia de Chaco.; The peasant and of small producers well as also indigenous organizations deploy a series of actions and strategies, both judicial and administrative political, to curb the processes of exclusion by those who traverse as consequence of the processes untied for hegemony model of agribusiness. In the province of Chaco, this activism was reflected in the resurgence, after the liguista process, of multiple peasant organizations and of small producers e indigenous, with the consequent the deployment of protest actions and of resistance. In this context of encirclement and expulsion of small producers and / or peasants of land is where I’m looking of expropriation as strategy to achieve access to land ownership. Well, the overall objective of this work refers to analyze and understand the processes land expropriation, in both –juridical and political action, to achieve access to land ownership or their ownership by small producers, peasants e indigenous in the province of Chaco.

La acreditación regional de la calidad universitaria en cuestión: ¿modelos en tensión en América del Sur?

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La acreditación regional de la calidad universitaria en cuestión: ¿modelos en tensión en América del Sur? Perrotta, Daniela Vanesa Este artículo se centra en el análisis de la política regional de acreditación universitaria del Mercado Común del Sur (MERCOSUR) en vistas a, primero, indagar cómo la política regional se ha difundido a la arena de política interna, generando impactos políticos y cambios institucionales en los Estados Parte (regionalismo regulatorio); y segundo, discutir la orientación de esta política regional.El trabajo se divide en tres secciones: primero, un breve apartado que describe la política de acreditación de la calidad (AC) del MERCOSUR; segundo, una sección analítica en dos niveles: los procesos de articulación y difusión de políticas entre la región y el ámbito doméstico y la identificación de modelos alternativos de AC en el MERCOSUR; tercero, una discusión final sobre el armado de criterios regionales de calidad y procedimientos de evaluación universitaria.

Gestos técnicos, morfología y rastros de uso en la alfarería prehispánica del sitio La Palmera 2 (provincia de Entre Ríos)

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Gestos técnicos, morfología y rastros de uso en la alfarería prehispánica del sitio La Palmera 2 (provincia de Entre Ríos) Ottalagano, Flavia Vanina; Brancatelli, Carolina; Darigo, Mariano Héctor; Iannelli, Lucía; Pereyra, Belén Este artículo presenta y discute los resultados preliminares obtenidos del estudio de los materiales cerámicos recuperados en el sitio arqueológico La Palmera 2, localizado en el Paraná medio (Departamento Paraná, provincia de Entre Ríos, nordeste de Argentina). Este sitio fue ocupado por grupos cazadores-recolectores complejos en torno al 1056-1032 + 47 AP. Se tienen en cuenta atributos relacionados con los aspectos formales, funcionales y técnicos de las vasijas, cuyo análisis permite avanzar hacia el estudio de la tecnología cerámica de un sector del río Paraná que todavía cuenta con un corpus de datos arqueológicos y una trayectoria de investigación relativamente escasa.; This paper presents and discusses the preliminary results obtained of the study of ceramic materials recovered from the archaeological site La Palmera 2, located in the middle Paraná (department of Paraná, province of Entre Ríos, northeast of Argentina).This site was occupied by complex hunter-gatherer groups around 1056-1032 + 47 b.p. Characteristics related to techno-morphological and functional aspects of the vessels have been taken into account, and these analyses have allowed advancements in the study of ceramic technology from an area of the Paraná River that still possesses a relatively scarce body of data and research work.

Organic Anion Transporter 5 (Oat5) Urinary Excretion Is a Specific Biomarker of Kidney Injury: Evaluation of Urinary Excretion of Exosomal Oat5 after N-Acetylcysteine Prevention of Cisplatin Induced Nephrotoxicity

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Organic Anion Transporter 5 (Oat5) Urinary Excretion Is a Specific Biomarker of Kidney Injury: Evaluation of Urinary Excretion of Exosomal Oat5 after N-Acetylcysteine Prevention of Cisplatin Induced Nephrotoxicity Bulacio, Romina Paula; Anzai, Naohiko; Ouchi, Motoshi; Torres, Adriana Monica Cisplatin is a commonly used chemotherapeutic agent. Its main side-effect is nephrotoxicity. It was reported that the organic anion transporter 5 (Oat5) urinary excretion is elevated, implying renal perturbation, when no modifications of traditional markers of renal damage are still observed in cisplatin-induced acute kidney injury (AKI). It was also demonstrated that Oat5 is excreted in urine by the exosomal pathway. This study was designated to demonstrate the specific response of the urinary excretion of exosomal Oat5 to kidney injury independently of other cisplatin toxic effects, in order to strengthen Oat5 urinary levels as a specific biomarker of AKI. To accomplish that aim, we evaluated if urinary excretion of exosomal Oat5 returns to its basal levels when cisplatin renal damage is prevented by the coadministration of the renoprotective compound N-acetylcysteine. Four days after cisplatin administration, AKI was induced in cisplatin-treated male Wistar rats (Cis group), as it was corroborated by increased urea and creatinine plasma levels. Tubular damage was also observed. In cotreated animals (Cis + NAC group), plasma urea and creatinine concentrations tended to return to their basal values, and tubular damage was improved. Urinary excretion of exosomal Oat5 was notably increased in the Cis group, but when renal injury was ameliorated by N-acetylcysteine coadministration, that increase was undetected. So, in this work we observed that urinary excretion of exosomal Oat5 was only increased if renal insult is produced, demonstrating its specificity as a renal injury biomarker. (Chemical Equation Presented).

Cine, tecnologías del erotismo y homosexualidades masculinas en Argentina

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Cine, tecnologías del erotismo y homosexualidades masculinas en Argentina Blazquez, Gustavo Este trabajo analiza los modos de amar entre varones, es decir modelos que permiten imaginar y experimentar las relaciones (homo)afectivas y las caricias entre hombres, a partir de la lectura de una serie de films argentinos. Específicamente nos interesa describir y comparar imágenes elaboradas en tres momentos históricos. En primer lugar nos detendremos en Extraña ternura, dirigido por Daniel Tinayre en 1964. Posteriormente será el turno de dos producciones de la década de 1980: Adiós Roberto (1985) de Enrique Dawi y Otra historia de amor (1986) de Américo Ortiz de Zárate. Por último, consideraremos El tercero de Rodrigo Guerrero estrenada en 2014 ya en los años de legalización del matrimonio civil entre sujetos del mismo sexo. Para acercarnos a estos textos visuales nos valemos de las nociones de «tecnologías del género» propuesta por Teresa de Lauretis y «guiones sexuales» elaborada por Gagnon y Simon (1974) en sus estudios sobre la conducta sexual. La lectura de las obras no se interesa exclusivamente por el texto visual y sonoro sino que atiende también diferentes indicios extradiegéticos y a la recepción del film a partir de datos construidos en un trabajo de campo junto con varones homosexuales en la ciudad de Córdoba.; This paper analyzes the ways of love between men, the models to imagine and experience (homo) affective relationships and caresses between men, from a reading of a number of Argentine films. Specifically we want to describe and compare images drawn in three historical moments. First we stop at Extraña ternura, directed by Daniel Tinayre in 1964. It will then be the turn of two productions of the 1980s: Adios Roberto (1985) by Enrique Dawi and Otra Historia de Amor (1986) of Américo Ortiz de Zárate. Finally, we consider El tercero by Rodrigo Guerrero released in 2014 in the years of legalization of civil marriage between same-sex individuals. To approach these visual texts we use the notions of «gender technology» proposed by Teresa de Lauretis and «sexual scripts» developed by Gagnon and Simon in the studies on sexual behavior. The reading of the works is not interested solely by visual and audible text but also serves extradiegetic different signs and the reception of the film from data constructed in an ethnography with gay men in the city of Cordoba.

Discapacidad y mendicidad en la era de la Convención: ¿postal del pasado?

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Discapacidad y mendicidad en la era de la Convención: ¿postal del pasado?; Disability and begging in the era of the Convention: a postcard from the past? Ferrante, Carolina En este trabajo se comparten los resultados de una investigación cualitativa que analizó los procesos sociales que conducen al ejercicio de la mendicidad en varones con discapacidad de la Ciudad de Buenos Aires, con la intención de problematizar el diagnóstico que afirma un cambio en las actitudes hacia esta minoría, a partir de la Convención Internacional sobre los Derechos de las Personas con Discapacidad. Al recuperar críticamente el modelo social de la discapacidad, se identifican cuatro itinerarios asociados a nuevas formas de vulnerabilidad promovidas por el capitalismo actual en contextos periféricos (pérdida del empleo, debilitamiento de redes, desempleo crónico y naturalización de la discapacidad como tragedia médica individual) que configuran las condiciones de posibilidad de esta postal. Se concluye que estos procesos evidencian la existencia de políticas de discapacitación y mecanismos de soportabilidad eregidos para sobrevivir en un mundo desigual, expresando el problema de la "nueva cuestión social".; This paper shares the results of a qualitative study that examined the social processes that lead to the practice of begging in men with disabilities in the City of Buenos Aires, with the intention to problematize the diagnosis asserting a change in attitudes toward this minority from the International Convention on the Rights of Persons with Disabilities. Critically retrieving the social model of disability, we identified four routes associated with new forms of vulnerability promoted by today's capitalism in peripheral contexts (job loss, weakening of networks, chronic unemployment and naturalization of disability as an individual medical tragedy), which configure the possibility conditions of this postcard. We conclude that these processes show the existence of disability policies and supportability mechanisms erected to survive in an unequal world, expressing the problem of the "new social question".

Photoinactivation of tyrosinase sensitized by folic acid photoproducts

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Photoinactivation of tyrosinase sensitized by folic acid photoproducts Dantola, Maria Laura; Zurbano, Beatriz Norma; Thomas, Andrés Héctor Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of biomolecules, accumulate in the skin of patients suffering from vitiligo, where there is a lack of melanin. Folic acid (PteGlu) is a conjugated pterin widespread in biological systems. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350 nm) in the presence of PteGlu and its photoproducts (6-formylpterin and 6-carboxypterin). The reactions were followed by UV-Vis spectrophotometry, enzyme activity measurement, fluorescence spectroscopy and HPLC. In this work, we present data that demonstrate unequivocally that solutions of tyrosinase exposed to UV-A irradiation in the presence of PteGlu, undergo enzyme inactivation. However, PteGlu itself causes a negligible effect on the activity of the enzyme. In contrast, PteGlu photoproducts are efficient photosensitizers. The tyrosinase inactivation involves two different pathways: (i) a photosensitization process and (ii) the oxidation of the enzyme by the hydrogen peroxide produced during the photooxidation of PteGlu and its photoproduct. The former pathway affects both the active site and the tryptophan residues, whereas the latter affects only the active site. The biological implications of the results are discussed.

Improvement in imazalil treatments in commercial packinglines to control green mold on lemon fruit

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Improvement in imazalil treatments in commercial packinglines to control green mold on lemon fruit Sepúlveda, M.; Cuevas, I. I.; Smilanick, J. L.; Cerioni, Luciana; Rapisarda, Viviana Andrea; Ramallo, J. Long distance to markets limits global competitiveness in lemon fruit production due to fungal postharvest decays, such as green mold caused by Penicillium digitatum. Imazalil, the main fungicide used, is formulated as an emulsifiable concentrate (IEC) and as a water-soluble sulphate salt (IS), the later being less commonly applied in most of the producing countries. The aim of the present report was to improve the effectiveness of imazalil treatments to control green mold in commercial scale. In both laboratory and commercial applications, IS was more effective than IEC. IS formulation applied in water followed by IEC applied in wax is an improved option that provided suitable disease control and optimal residue loading >2.0 mg L−1 without exceeding the maximum residue levels. Additionally, IMZ residues remained at acceptable levels after 28 days at 7 °C, assuring the protection of lemon fruit for long periods of storage and transports.

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