Role of basin width variation in tectonic inversion : insight from analogue modelling and implications for the tectonic inversion of the Abanico Basin, 32°-34° S, Central Andes Jara, Pamela; Likerman, Jeremias; Winocur, Diego Alejandro; Ghiglione, Matias; Cristallini, Ernesto Osvaldo; Pinto, Luisa; Charrier González, Reynaldo We use analogue modelling to investigate the response of compressional deformation superimposed on an extensional basin with along-strike changes in width. Parameters described include extension and shortening distribution and directions, orientation of structures and degree of basin inversion. Two types of model are presented: in the first (Type I), an extensional basin is constructed with variable width (applying differential extension) and subsequently inverted by homogeneous shortening; in the second (Type II), an extensional basin with constant width is subsequently inverted by inhomogeneous shortening (differential compression). From our observations, we compare both types of model to structural patterns observed in some natural cases from the Central Andes. Both models generate oblique structures, but in the Type II model a significant rotation is characteristic. Our results suggest that in the Central Andes region between 32° and 338S, the Abanico Basin may correspond to a basin of smaller area compared to the larger basin south of 33°S. Our Type I model further explains some patterns observed there, from which we conclude that the control exercised by the width of a pre-existing basin should be considered when interpreting the geological evolution of that area of the Andes.

Effective temperature from fluctuation-dissipation theorem in systems with bipartite eigenmode entanglement Bortolin, Tomás Sebastián; Iucci, Carlos Aníbal In thermal equilibrium, the fluctuation-dissipation theorem relates the linear response and correlation functions in a model and observable independent fashion. Out of equilibrium, these relations still hold if the equilibrium temperature is replaced by an observable and frequency-dependent parameter (effective temperature). When the system achieves a long-time thermal state all of these effective temperatures should be equal and constant. Following this approach we examine the long-times regime after a quantum quench in a system with bipartite entanglement in which the asymptotic values of the observable are compatible with the ones obtained in a Gibbs ensemble. We observe that when the initial entanglement is large, and for a large range of (intermediate) frequencies, the effective temperatures corresponding to the analyzed local and nonlocal operators approach an approximate constant value equal to the temperature that governs the decay of correlations. Still, the residual frequency dependence in the effective temperature, and the differences observed among observables, discards strict thermalization.

Sucrose in cyanobacteria: From a salt-response molecule to play a key role in nitrogen fixation Kolman, María de los Ángeles; Nishi, Carolina Nancy; Perez Cenci, Macarena; Salerno, Graciela Lidia In the biosphere, sucrose is mainly synthesized in oxygenic photosynthetic organisms, such as cyanobacteria, green algae and land plants, as part of the carbon dioxide assimilation pathway. Even though its central position in the functional biology of plants is well documented, much less is known about the role of sucrose in cyanobacteria. In those prokaryotes, sucrose accumulation has been associated with salt acclimation, and considered as a compatible solute in low-salt tolerant strains. In the last years, functional characterizations of sucrose metabolizing enzymes, metabolic control analysis, cellular localization of gene expressions, and reverse genetic experiments have revealed that sucrose metabolism is crucial in the diazotrophic growth of heterocystic strains, and besides, that it can be connected to glycogen synthesis. This article briefly summarizes the current state of knowledge of sucrose physiological functions in modern cyanobacteria and how they might have evolved taking into account the phylogenetic analyses of sucrose enzymes.

Ab-initio and DFT calculationd on molecular structure, NBO, HOMO-LUMO study and a new vibrational analysis of 4-(dimethylamino) benzaldehyde Rocha, Mariana; Di Santo, Alfredo Alejandro; Arias, Juan Marcelo; Gil, Diego Mauricio; Ben Altabef, Aída The experimental and theoretical study on the molecular structure and a new vibrational analysis of 4-(Dimethylamino) Benzaldehyde (DMABA) is presented. The IR and Raman spectra were recorded in solid state. Optimized geometry, vibrational frequencies and various thermodynamic parameters of the title compound were calculated using DFT methods and are in agreement with the experimental values. A detailed interpretation of the IR and Raman spectra of the title compound were reported. The stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analyzed using NBO analysis and AIM approach. The HOMO and LUMO analysis were used to determine the charge transfer within the molecule and some molecular properties such as ionization potential, electron affinity, electronegativity, chemical potential, hardness, softness and global electrophilicity index. The TD-DFT approach was applied to assign the electronic transitions observed in the UV–visible spectrum measured experimentally. Molecular electrostatic potential map was performed by the DFT method. According to DSC measurements, the substance presents a melting point of 72.34 °C and decomposes at temperatures higher than 193 °C.

Artificial additions for cement: reproduction in laboratory of fluidized bed ash Guilarducci, Anabela Guadalupe; Beltramini, Lorelei; Carrasco, María Fernanda; Chiovetta, Mario Gabriel; Grether, Rudy Omar This paper presents a experimental laboratory simulation of wastes that will be produced as a result of the implementation of a circulating fluidized bed (CFB) steam generator that is being built in the town of Rio Turbio in the province of Santa Cruz (Argentina ). For this analysis, the information published in the environmental impact study conducted by the Grupo Isolux Corsán SA and Others - JV (2008) was used. The design data associated with the operation of the plant was extracted from said document. This power plant will use raw coal as fuel, thus introducing into the reactor a significant proportion of sterile (an inert material that is extracted with coal composed mainly of clay). Based on fuel and plant operation characteristics, it is expected as a residue of the combustion process a potentially reactive material that could be used as an artificial admixture for cement. Time and temperature needed to generate the specified chemical composition for the residue were the most important parameters in the experimental simulation. In order to achieve expected crystallographic structure of these ashes, the assessment of the cooling method was critical. The results of chemical composition and x-ray diffraction show that, in principle, laboratory simulation can produce ashes similar to those expected to be produced at the power plant. Additionally, from the evaluation of the simulated-ashes characteristics, it seems possible to use the real residue from the steam generator as a pozzolanic admixture for cement.

Las PyMEs en la era neo-desarrollista y (¿) las herramientas para el desarrollo (?) : contribución crítica desde la experiencia argentina reciente Seiler, Cristhian Rubén; Fernández, Víctor Ramiro Este trabajo tiene dos propósitos vinculados. El primero, consiste en evaluar el desempeño de las pequeñas y medianas empresas (PyMEs) del sector industrial en Argentina bajo el período denominado neo-desarrollismo (2002-2014). Se observa la actuación de las PyMEs en la creación de empleo, su participación en el crecimiento económico, las actividades más dinámicas, así como la inserción en el mercado externo. A partir de esta evaluación, el segundo propósito es aportar algunos elementos para considerar los riesgos de aceptar acríticamente las políticas de desarrollo que propician la inserción rápida de las PyMEs en las cadenas globales de valor (CGV). Se considera precautoriamente que la implementación de la política PyMEs bajo dicha estrategia puede abonar -antes que revertir- los efectos de desarticulación y fragmentación productiva que acentúan el derrotero estructural de las PyMEs. En buena medida, ello tiene su fundamento en que esta iniciativa se interesa más en la adaptación de las PyMEs a los requerimientos de las empresas transnacionales antes que a potenciar a estos actores bajo una estrategia nacional de desarrollo que permita avanzar integralmente sobre las debilidades estructurales analizadas. Por esta razón, en la parte final del trabajo se advierte la necesidad de vincular la atención en las CGV con una estrategia nacional de desarrollo, multi-escalarmente articulada por el Estado.; This paper has two linked purposes. The first one is to analyze the performance of small and medium enterprises (SMEs) of the Argentinean industrial sector under the so-called neodevelopmentalism period (2002-2014). For this, it observes SMEs’ role in job creation and economic growth, their participation in most dynamics activities and their integration into the international economy. Based on this evaluation, the second purpose is to provide some tools in order to consider the risk of accepting, in an acritical way, developing policies that promote SME’s rapid economic integration in Global Value Chains (GVC). It is preventively considered that SME policies implementation under those strategies, actually reinforce SME productive disarticulation and fragmentations that deepen their structural path instead of reversing it. To a great extent, these initiatives seem to have their basis on adapting SMEs to transnational companies’ requirements instead of empowering these actors under a national development strategy that allows them to get over the analyzed problems. For this reason, at the end of the paper, it is warned the need of combining the attention on GVC with a national development strategy and articulated multi-scalar by State.

Maternal teaching of the symbolic function of a scale model; La enseñanza materna de la función simbólica de una maqueta Jauck, Daniela Eva; Maita, María del Rosario; Mareovich, Florencia; Peralta, Olga Alicia Esta investigación explora cómo las madres naturalmente guían a sus niños en la utilización de un objeto simbólico, una maqueta. Participaron 19 parejas de madres y niños de dos años y medio de edad. El niño debía encontrar un juguete escondido en una habitación pequeña valiéndose de una maqueta que la representaba. Se encontró que las madres emplearon tres tipos de estrategias: correspondencia maqueta-habitación, experiencia de vida, y nombre de los objetos; siendo la correspondencia el camino preferido. Las madres siempre respondieron a las conductas de los niños ofreciendo un feedback al evaluar sus búsquedas tanto correctas como incorrectas. El feedback correctivo impactó en la ejecución infantil cuando la madre previamente había utilizado estrategias como correspondencia y experiencia, no así en el caso de nombre. En términos generales, los resultados ilustran cómo las madres naturalmente guían los conocimientos culturales de sus niños, estructurando la interacción de una manera particular y desplegando estrategias de enseñanza y corrección en virtud de las respuestas de los niños y de las características de la tarea.; This study explores how mothers naturally guide their children in the use of a symbolic object, a scale model. Nineteen mothers, along with their two-and-a-half-year-old children, participated. The children had to find a toy hidden in a small room by using a scale model that represented it. It was found that mothers used three kinds of strategies: model-room correspondence, life experience and the names of the objects; with correspondence being the preferred strategy. The mothers were very responsive to their children, offering feedback in order to evaluate both their correct and incorrect searches. The corrective feedback affected the children’s performance when mothers had previously used strategies like correspondence and experience, but not in the case of name. In general terms, the results illustrate how mothers naturally guide the cultural knowledge of their children, structuring the interaction in a particular way and providing teaching and correction strategies in line with the responses of their children and the characteristics of the task.

Dissimilar Effects of World News Announcements on Euro/Dollar/Yen Exchange Rates: An Econophysics Approach Matesanz Gómez, David; Ortega, Guillermo José This paper revisits the issue of the influence of macro-economic announcements over the exchange rates volatility, but from a different perspective as it is the usual in the econometric literature. By quantifying the impact of world-wide macroeconomic information published in the economic calendar in several recent years we were able to construct long events' time series with the objective to test whether they influence exchange rate volatilities in several currencies. In order to do that, Granger causality test was employed by using a computational approach. Our results show that announcements from U.S.A are, by far, the most important influence over the three spot forex quotes, Euro/Dollar, Euro/Yen and Dollar/Yen. The method proposed here opens the door to address several open questions until now.

Todo mezclado, hermanado: Antropologie in America Latina; Spunti per una rilettura delle pratiche culturali latinoamericane Annecchiarico, Milena Este trabajo propone algunas perspectivas y reflexiones sobre las teorías del mestizaje y de la transculturación, considerando los aportes actuales de las antropologías latinoamericanas. Las narrativas nacionales hacen referencia al mestizaje como característica fundamental del continente: el todo mezclado cubano, el crizol de razas argentino, la democracia racial brasileña, a partir de mezclas entre las que se consideran las ?tres raíces? de las culturas americanas: europeos, indigenas y africanos. ¿Qué dicen a tal propósito las disciplinas sociales? Con el propósito de recuperar algunas propuestas formuladas por autores latinoamericanos del siglo XX, analizo la teoría de la transculturación propuesta por el intelectual cubano Fernando Ortiz y la teoría de fagocitación o sabiduría de América del estudioso argentino Rodolfo Kush. Estas propuestas situadas permiten comprender en otros términos las estrategias de resistencia y de narraciones anti-hegemónicas a través de las performance culturales, la oralidad, las diversas filosofías políticas americanas, una perspectiva que recientemente fue reformulada por la teoría decolonial latinoamericana.

Desvalimiento psicosocial en adolescentes violentos; Violent adolescent psychosocial helplessness Cryan, Glenda Martha; Quiroga, Susana En este artículo se analiza un caso clínico de un adolescente violento que ha sido derivado a tratamiento terapéutico por una institución escolar. El objetivo es poder demostrar que los actos violentos que constituyen el motivo de consulta suelen encubrir el predominio de una alta vulnerabilidad psicosocial, que ubica a estos adolescentes en una situación de riesgo, desamparo y desvalimiento psíquico. Se exponen algunas de las principales conceptualizaciones acerca de la violencia y de la vulnerabilidad propia de la adolescencia y un modelo de abordaje terapéutico grupal específico al que denominamos Grupo de Terapia FocalizadaGTF. Se analizan diferentes viñetas del caso clínico a lo largo del GTF y se incluye una técnica gráfica (árbol genealógico) que representa la construcción mental de los vínculos intergeneracionales del paciente y un familiar directo. El análisis permitió observar que los problemas de conducta y de aprendizaje son la pantalla de situaciones traumáticas graves actuales y pasadas imposibles de ser verbalizadas en forma espontánea. La mejora sintomática permite pensar en un pronóstico positivo para este paciente que al encontrar respuesta a su demanda, pudo establecer una transferencia con la terapeuta y el grupo y quebrar así con el círculo vicioso de ser rechazado y abandonado.; In this article, a violent adolescent report who has been referred to therapeutic treatment for an educational institution is analyzed. The goal is to demonstrate that violent acts constituting the reason for consultation often conceal the predominance of high psychosocial vulnerability, which places these adolescents in a situation of risk, homelessness and mental helplessness. Some major conceptualizations about violence and the own vulnerability of adolescence and a model specific group therapeutic approach called Focalised Therapy Group- FTG are shown. Different clinical vignettes of the report along the FTG are analyzed. A graphical technique (family tree) representing the mental construction of intergenerational bonds of the patient and a family member is included. This analysis allowed to observe that behavior and learning problems are the display of current and past severe trauma events which were impossible to be verbalized spontaneously. Symptomatic improvement suggests a positive prognosis for this patient who found answer to his demand, could establish a transference to the therapist and the group and thus break the vicious cycle of being rejected and abandoned.

El mutualismo católico en Argentina: el Círculo de Obreros de Rosario en la primera mitad del siglo XX; Catholic Mutualism in Argentina: The Catholic Worker Circle of Rosario in the First Half of the 20th Century; O mutualismo católico na Argentina: o Círculo de Obreiros de Rosário na primeira metade do século XX Mauro, Diego Alejandro Las dificultades atravesadas por los Círculos Católicos de Obreros en Argentina han tendido a verse como una consecuencia de la implantación de los modelos centralizadores propiciados por Roma durante el período de entreguerras, entre ellos, la Unión Popular Católica Argentina y la Acción Católica. En el presente artículo se revisa este argumento a partir de un estudio de caso: el del Círculo de Obreros de la ciudad de Rosario. Se analizan las prestaciones de la entidad a la luz de las condiciones generales del mutualismo de entreguerras, las tendencias cambiantes en el rol del Estado y los sindicatos, y el impacto de las élites demócratas cristianas al frente de la entidad desde mediados de la década de 1910.; The difficulties experienced by Catholic Worker Circles in Argentina have tended to be seen as a consequence of the implantation of the centralizing models promoted by the Vatican during the interwar period, among them, the Unión Popular Católica Argentina and Catholic Action. The article examines this argument through a specific case study: that of the Worker Circle of the city of Rosario. The benefits provided by the entity are analyzed in the light of the general conditions of interwar mutualism, the changing tendencies in the role of the State and trade unions, and the impact of the Christian Democrat elites that headed the entity since the middle of the second decade of the 20th century.; As dificuldades pelas quais os Círculos Católicos de Obreiros na Argentina atravessaram vêm sendo vistas como uma consequência da implantação dos modelos centralizadores propiciados por Roma durante o período de entreguerras, entre eles, a União Popular Católica Argentina e a Ação Católica. No presente artigo, revisa-se esse argumento a partir de um estudo de caso: o do Círculo de Obreiros da cidade de Rosário. Analisam-se as prestações da entidade à luz das condições gerais do mutualismo de entreguerras, as tendências mutáveis no papel do Estado e dos sindicatos, e o impacto das elites democráticas cristãs à frente da entidade desde meados da década de 1910.

El régimen de las sociedades residuales previsto en la ley general de sociedades argentina Abdala, Martin Eugenio Ese cuadro de situación se modificará sustancialmente a partir de la entrada en vigencia del Código Civil y Comercial Unificado y de la Ley General de Sociedades. El nuevo régimen unifica el sistema societario y crea una figura flexible aplicable a todas las sociedades que no se hubieran constituido como una sociedad regular de alguno de los tipos legislados y que, por esa razón, podemos denominar "sociedades residuales", e incluye las sociedades civiles, las atípicas, las irregulares y las de hecho. La nueva legislación mantiene el criterio de considerar que las sociedades son sujetos de derecho desde su constitución y, tomando posición en el debate referido al alcance de la personalidad jurídica de las anómalas, dispone que las sociedades residuales son personas jurídicas plenas y abroga las disposiciones que las caracterizaban como precarias y limitadas. En una decisión plausible, la Ley General de Sociedades modifica el régimen de la Ley de Sociedades Comerciales anterior y que el contrato social pueda ser invocado entre los socios y que incluso sea oponible a los terceros que conocían la existencia de la convención al tiempo de la contratación o del nacimiento de la relación obligatoria, superando de esa manera la impropia limitación que preveía la anterior redacción de la norma. También es correcta la reforma cuando dispone que las cláusulas del contrato relativas a la representación, administración, organización y gobierno de la sociedad pueden ser opuestas a los socios y a los terceros que las conocieron. Sin embargo es una notable deficiencia que la norma no prevé ninguna solución para las sociedades que no han instrumentado en modo alguno el contrato o lo hicieron de forma incompleta o precaria. La Ley de Sociedades Comerciales prevé que los socios de una sociedad anómala puede exigir, en cualquier momento, su disolución, la cual se produce salvo que la mayoría resuelva regularizar la sociedad. La Ley General de Sociedades da un paso adelante al limitar el derecho a requerir la disolución de la sociedad residual sólo para los casos en los que el contrato de sociedad no se hubiera instrumentado por escrito, el mismo no previera un plazo de duración de la sociedad, o ese plazo estuviera vencido. Pero como contracara deroga el procedimiento de regularización de la sociedad anómala y lo reemplaza por un régimen de subsanación que exige un acuerdo unánime de los socios, lo que representa un enorme retroceso en relación al régimen anterior. En materia de responsabilidad de los socios la reforma realiza una profunda modificación consagrando, en lugar de la responsabilidad solidaria e ilimitada, la responsabilidad simplemente mancomunada y por partes iguales, lo cual es también un claro retroceso con relación al régimen previsto por la Ley de Sociedades Comerciales. Por lo demás, el plausible que la reforma zanje, de forma correcta, una antigua discusión doctrinaria, estableciendo que las sociedades residuales pueden ser titulares de bienes registrables.

El diagnóstico de la demencia precoz y la esquizofrenia en Argentina, 1920-1940; The diagnose of dementia praecox and schizophrenia in Argentina, 1920-1940; O diagnóstico da demência precoce e a esquizofrenia na Argentina, 1920-1940 Golcman, Aida Alejandra En este artículo rastreamos las ideas de los psiquiatras argentinos sobre el diagnóstico de demencia precoz de Emil Kraepelin, y el de esquizofrenia de Eugen Bleuler, desde la década de 1920 hasta la década de 1940. En este período se superpusieron las producciones teóricas de ambas patologías y su uso con pacientes. Ponemos la lupa en los artículos, ya que era allí donde se plasmaba el saber teórico de estos médicos y su interpretación de las lecturas extranjeras, sobre las que se basaban sus producciones locales. Esta investigación conforma una posible puerta de entrada para entender la formación del “ojo clínico” de los psiquiatras del centro del país en las primeras décadas del siglo XX.; In this article, we trace Argentine psychiatrists' understanding of Emil Kraeplin's theory of dementia praecox and Eugene Bleuler's theory of schizophrenia, during the 1920s, 30s, and 40s. In this period, the theories and practices related to both conditions overlapped significantly. We focus on articles in psychiatric journals because they reflect the theoretical knowledge of these psychiatrists and their local interpretations of foreign texts. This research offers a novel approach to understanding the formation of the «clinical eye» of psychiatrists in the country's capital during the first decades of the twentieth century.; O presente artigo procura identificar as ideias de psiquiatras argentinos sobre o diagnóstico de demência precoce de Emil Kraepelin e de esquizofrenia de Eugen Bleuler, entre as décadas de 1920 e 1940. Trata-se de um período no qual se sobrepunham as produções teóricas de ambas patologias e sua utilização. Nesse sentido, focalizamos nos artigos, onde estes médicos modelaram o seu conhecimento teórico e sua interpretação de leituras estrangeiras, a partir da qual basearam suas produções locais. Esta pesquisa constitui uma possível porta de entrada para a compreensão da formação do “olhar clínico” dos psiquiatras na região central da Argentina, durante as primeiras décadas do século XX.

Mitochondrial calcium handling in normotensive and spontaneously hypertensive rats: correlation with systolic blood pressure levels Ciocci Pardo, Alejandro; Rinaldi, Gustavo Juan; Mosca, Susana Maria The aim was to study the mitochondrial Ca2+ handling of mitochondria isolated from normotensive Wistar Kyoto(WKY) and spontaneously hypertensive rats (SHR) hearts and to establish a possible correlation with systolic blood pressure (SBP). Mitochondrial swelling after Ca2+ addition, Ca2+-retention capacity (CRC) by calcium green method, and membrane potential (ΔΨm) were assessed. SBP was 124 ± 1 (WKY) and 235 ± 6 mm Hg(SHR). CRC, Ca2+ response and ΔΨm were lower in SHR than WKY mitochondria. The conclusion is: the more depolarized state of SHR than WKY mitochondria results in an abnormal Ca2+ handling and this event is closelyassociated with the SBP.

Más allá del principio contributivo: cambios y continuidades en la política social argentina, 2003-2011 Alonso, Guillermo Victor; Di Costa Tita, Valeria Noemi El objetivo de este artículo es presentar las transformaciones producidas en las políticas sociales argentinas durante el periodo del gobierno de Néstor Kirchner (2003-2007) y del primer mandato de Cristina Fernández de Kirchner (2007-2011). No haremos una enumeración de políticas y medidas de modo exhaustivo, pero la descripción y análisis permitirá mostrar, al considerar los programas y sistemas de cobertura poblacional más extendida, la corriente principal de la política social argentina durante estos años. En especial, analizaremos los cambios producidos en el sistema de seguridad social, y mostraremos que la estrategia que inicialmente pareció encaminada a simplemente restaurar la centralidad del seguro social contributivo sobre bases más amplias, innovó planteando rupturas significativas con la lógica del principio contributivo como ar- ticulador del sistema de protección social.

Excitation functions for the production of radionuclides by neutron-induced reactions on C, O, Mg, Al, Si, Fe, Co, Ni, Cu, Ag, Te, Pb, and U up to 180 MeV Michel, R.; Hansmann, David; Neumann, S.; Glasser, W.; Schuhmacher, H.; Dangendorf, V.; Nolte, R.; Herpers, U.; Smirnov, A.N.; Ryzhov, I.V.; Prokofiev, A.V.; Malmborg, P.; Kollár, D.; Meulders, J.-P. Irradiation experiments with well-characterized, quasi mono-energetic neutrons of energies between 32.7 MeV and 175.4 MeV were performed at UCL/Louvain-la-Neuve and TSL/Uppsala. The abundances of relatively short-lived residual radionuclides from 13 different target elements were determined by γ-spectrometry. More than 100 excitation functions of neutron-induced reactions were unfolded based on the neutron spectra and the radionuclide abundances with the aid of additional information that was provided by "guess" excitation functions calculated by the TALYS 1.0 code. The results are compared with the sparse existing data from other authors. The new excitation functions were validated by calculation of and comparison with experimental thick-target production rates. Consistency with neutron excitation functions up to 1.6 GeV, which were derived earlier by unfolding the thick-target production rates, was so demonstrated.

Insights into the mechanism of the reaction between hydrogen sulfide and peroxynitrite Cuevasanta, Ernesto; Zeida Camacho, Ari Fernando; Carballal, Sebastián; Wedmann, Rudolf; Morzan, Uriel N.; Trujillo, Madia; Radi, Rafael; Estrin, Dario Ariel; Filipovic, Milos R.; Alvarez, Beatriz Hydrogen sulfide and peroxynitrite are endogenously generated molecules that participate in biologically relevant pathways. A revision of the kinetic features of the reaction between peroxynitrite and hydrogen sulfide revealed a complex process. The rate constant of peroxynitrite decay, (6.65 ± 0.08) × 103 M-1 s-1 in 0.05 M sodium phosphate buffer (pH 7.4, 37 °C), was affected by the concentration of buffer. Theoretical modeling suggested that, as in the case of thiols, the reaction is initiated by the nucleophilic attack of HS- on the peroxide group of ONOOH by a typical bimolecular nucleophilic substitution, yielding HSOH and NO2 -. In contrast to thiols, the reaction then proceeds to the formation of distinct products that absorb near 408 nm. Experiments in the presence of scavengers and carbon dioxide showed that free radicals are unlikely to be involved in the formation of these products. The results are consistent with product formation involving the reactive intermediate HSSH and its fast reaction with a second peroxynitrite molecule. Mass spectrometry and UV-Vis absorption spectra predictions suggest that at least one of the products is HSNO2 or its isomer HSONO.

Dendrogeomorphic reconstruction of flash floods in the Patagonian Andes Casteller, Alejandro; Stoffel, Markus; Crespo, Sebastián Andrés; Villalba, Ricardo; Corona, Christophe; Bianchi, Emilio Flash floods represent a significant natural hazard in small mountainous catchments of the Patagonian Andes and have repeatedly caused loss to life and infrastructure. At the same time, however, documentary records of past events remain fairly scarce and highly fragmentary in most cases. In this study, we therefore reconstruct the spatiotemporal patterns of past flash flood activity along the Los Cipreses torrent (Neuquén, Argentina) using dendrogeomorphic methods. Based on samples from Austrocedrus chilensis, Pseudotsuga menziesii, and Nothofagus dombeyi, we document 21 flash flood events covering the period A.D. 1890-2009 and reconstruct mean recurrence intervals of events at the level of individual trees being impacted, which varies from 4 to 93. years. Results show that trees tend to be older (younger) in sectors of the torrent with gentler (steeper) slope gradients. Potential triggers of flash floods were analyzed using daily temperature and precipitation data from a nearby weather station. Weather conditions leading to flash floods are abundant precipitations during one to three consecutive days, combined with temperatures above the rain/snow threshold (2. °C) in the whole watershed.

La Josefina Au-Ag deposit (Patagonia, Argentina): A Jurassic epithermal deposit formed in a hot spring environment Moreira, Pilar; Fernandez, Raul Roberto The La Josefina Jurassic epithermal Au-Ag deposit located in Patagonia, Argentina, developed in an extensional setting of a back-arc environment, associated with a widespread Middle-Late Jurassic calc-alkaline volcanism. Block faulting has juxtaposed shallow level features evidenced by hot spring manifestations, hydrothermal eruption breccias and Au-rich veins, which suggest that mineralization in these veins, could extend far below the depths already tested by core drilling. Veins are filled by quartz, chalcedony, opal and minor adularia and barite with massive, comb, cockade, colloform-crustiform bandings and lattice-bladed textures. Ore minerals include electrum, Ag-rich sulfosalts (freibergite), pyrite, galena, sphalerite, chalcopyrite and specular hematite with minor arsenopyrite, marcasite, tetrahedrite and bornite. Four mineralizing stages have been identified, the first two (S1 and S2) are Au and Ag-rich, with temperatures ranging from 225 to 290° and salinities from up to 15 wt.% in S1 decreasing to ~1 wt.% NaCl in S2. The third stage (S3) displays higher base metal contents at lower temperatures (~200 °C). Finally, the last stage (S4) is barren with temperatures lower than 100 °C. Veins are surrounded by a proximal alteration halo of quartz + pyrite ± adularia ± illite followed outwards by illite/smectite interstratified clays and smectites (with less chlorite) to a propylitic zone. Stable isotope values calculated for the fluids show a mostly meteoric origin for mineralization fluids. Such distinct features place the La Josefina deposits in a hot spring environment with evidences of being formed at a proximal position of the Jurassic paleosurface and paleowater level.

Temperature evolution of the effective magnetic anisotropy in the MnCr2O4 spinel Tobia, Dina; Milano, Julian; Causa, Maria Teresa Beatriz; Winkler, Elin Lilian In this work, we present a study of the low temperature magnetic phases of polycrystalline MnCr2O4 spinel through dc magnetization and ferromagnetic resonance spectroscopy (FMR). Through these experiments, we determined the main characteristic temperatures: TC ∼ 41K and TH ∼ 18K corresponding, respectively, to the ferrimagnetic order and to the low temperature helicoidal transitions. The temperature evolution of the system is described by a phenomenological approach that considers the different terms that contribute to the free energy density. Below the Curie temperature, the FMR spectra were modeled by a cubic magnetocrystalline anisotropy to the second order, with K1 and K2 anisotropy constants that define the easy magnetization axis along the 〈110〉 direction. At lower temperatures, the formation of a helicoidal phase was considered by including uniaxial anisotropy axis along the [110] propagation direction of the spiral arrange, with a Ku anisotropy constant. The values obtained from the fittings at 5K are K1 = -2.3 × 104 erg cm-3, K2 = 6.4 × 104 erg cm-3 and Ku = 7.5 × 104 erg cm-3.