Complex oscillatory redox dynamics with signaling potential at the edge between normal and pathological mitochondrial function

The time-keeping properties bestowed by oscillatory behavior on functional rhythms represent an evolutionarily conserved trait in living systems. Mitochondrial networks function as timekeepers maximizing energetic output while tuning reactive oxygen species (ROS) within physiological levels compatible with signaling. In this work, we explore the potential for timekeeping functions dependent on mitochondrial dynamics with the validated two-compartment mitochondrial energetic-redox (ME-R) computational model, that takes into account (a) four main redox couples [NADH, NADPH, GSH, Trx(SH)2], (b) scavenging systems (glutathione, thioredoxin, SOD, catalase) distributed in matrix and extra-matrix compartments, and (c) transport of ROS species between them. Herein, we describe that the ME-R model can exhibit highly complex oscillatory dynamics in energetic/redox variables and ROS species, consisting of at least five frequencies with modulated amplitudes and period according to power spectral analysis. By stability analysis we describe that the extent of steady state—as against complex oscillatory behavior—was dependent upon the abundance of Mn and Cu, Zn SODs, and their interplay with ROS production in the respiratory chain. Large parametric regions corresponding to oscillatory dynamics of increasingly complex waveforms were obtained at low Cu, Zn SOD concentration as a function of Mn SOD. This oscillatory domain was greatly reduced at higher levels of Cu, Zn SOD. Interestingly, the realm of complex oscillations was located at the edge between normal and pathological mitochondrial energetic behavior, and was characterized by oxidative stress. We conclude that complex oscillatory dynamics could represent a frequency- and amplitude-modulated H2O2 signaling mechanism that arises under intense oxidative stress. By modulating SOD, cells could have evolved an adaptive compromise between relative constancy and the flexibility required under stressful redox/energetic conditions.Fil: Kembro, Jackelyn Melissa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Cortassa, Sonia del Carmen. University Johns Hopkins; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aon, Miguel A.. University Johns Hopkins; Estados Unido

La persistencia de modelos falsados. El Modelo Comunicacional de Lasswell: un caso de "resistencia teórica"

El trabajo se divide en dos partes: En una primera instancia retoma categorías del racionalismo crítico para las ciencias sociales: la Lógica Situacional y el Principio de Racionalidad. En un segundo momento, se presentará un caso de las Ciencias de la Comunicación: el modelo que propone Harold Lasswell (1948) para analizar un acto comunicativo

Promoting Scientific Culture: A Review of Public Policies in the Ibero-American Countries

The article presents an overview of a recent study aimed at describing how the efforts to improve the public scientific culture (SC) have gained ground in the broader frame of public policies for S&T in Ibero-America. The purpose is to assess to what extent the discourse of the governmental agencies reflects the concern over the matter and in which way the usual ‘loud and clear´ claims in this sense turn into operative strategies, actions and tools. The outcomes suggest a complex scenario. Although most of the countries explicitly encompass the need to improve public engagement with science in their respective sectorial Plans, the interest put forth at this rethorical level doesn’t always match with the type of (limited) actions actually carried on in a factual level. Besides, the huge heterogeneity of concepts, tools, practices and aims reported in each context as part of the promotion of scientific culture not only entails a difficulty to achieve a reliable picture of the regional policies in this field but, at the same time, hinders the possibility of a more accurate assessment and comparison among them

Principals diccionaris catalans de 1637 a 1939

El doctor Joan Solà i Cortassa valora la donació feta pel senyor Josep Rovira i Puig d'una col·lecció d'uns cent quaranta llibres (originals i facsímils) relacionats amb la llengua catalana i datats entre el segle XIV i el segle XX (principalment diccionaris, però també gramàtiques, refranyers, vocabularis, etc.) i fa una relació, breument comentada, de les més destacades obres lexicogràfiques a partir del segle XVI

Media framing of techno-environmental controversies: A case study of the Paper-Mills Conflict between Argentina and Uruguay

El artículo adopta la teoría del framing para abordar la construcción mediática de la controversia tecnoambiental vigente entre Argentina y Uruguay, suscitada a raíz de la instalación de una planta productora de pasta de celulosa en inmediaciones de la localidad uruguaya de Fray Bentos. El análisis está centrado en las respectivas coberturas realizadas por dos medios de prensa gráfica argentinos -los diarios Clarín y Página 12- en tres etapas clave de la evolución del conflicto. Un corpus conformado por un total de 1004 artículos fue examinado mediante un protocolo de registro elaborado en base a instrumentos previamente probados, destinado a observar cuantitativamente la incidencia de cinco frames establecidos a priori: a) ambiental; b) científico-técnico; c) políticojurídico; d) social; e) de causas-consecuencias económicas. La evidencia indica que, por amplia mayoría, los medios analizados representaron la controversia en términos político-jurídicos, opacando drásticamente su origen ambiental y las discrepancias de índole científica y técnica involucradas en su raíz y desarrollo. En el artículo se discuten algunos resultados de la experiencia, como así también las limitaciones y posibilidades de extender la tipología de encuadres aquí ensayada a otras coberturas mediáticas de situaciones semejantes, con independencia de su objeto específico.This article embraces the framing studies’ perspective to approach the media construction of the current techno-environmental controversy between Argentina and Uruguay, due to the location of an industrial plant to produce cellulose paper in the uruguayan community of Fray Bentos. The analysis is centered on the respective coverages developed by two argentinean print media –daily newspapers Clarín and Página 12– during three key stages in the evolution of the conflict. A sample composed of 1004 articles was examined using a protocol based in previously tested instruments, which was elaborated to quantify the incidence of five frames established a priori: a) environmental; b) scientific-technological; c) political-juridical; d) social; e) of economic causes & consequences. The evidence collected indicates that the analyzed media represented the controversy mostly in political-juridical terms and drastically overshadowed its environmental origins and the discrepancies of scientific and technical nature involved in its roots and development. The article discusses some results of the research experience, as well as the limitations and posibilites to extend the framing typology rehearsed here to other media coverages of similar situations, independently of its specific object.Fil: Cortassa, Carina. Universidad Nacional de Entre Rios; ArgentinaFil: Andres, Gonzalo Dario. Universidad Nacional de Entre Rios; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wursten, Andrés. Universidad Nacional de Entre Rios; Argentin

Why Homeodynamics, Not Homeostasis?

Ideas of homeostasis derive from the concept of the organism as an open system. These ideas can be traced back to Heraclitus. Hopkins, Bernard, Hill, Cannon, Weiner and von Bertalanffy developed further the mechanistic basis of turnover of biological components, and Schoenheimer and Rittenberg were pioneers of experimental approaches to the problems of measuring pool sizes and dynamic fluxes. From the second half of the twentieth century, a biophysical theory mainly founded on self-organisation and Dynamic Systems Theory allowed us to approach the quantitative and qualitative analysis of the organised complexity that characterises living systems. This combination of theoretical framework and more refined experimental techniques revealed that feedback control of steady states is a mode of operation that, although providing stability, is only one of many modes and may be the exception rather than the rule. The concept of homeodynamics that we introduce here offers a radically new and all-embracing concept that departs from the classical homeostatic idea that emphasises the stability of the internal milieu toward perturbation. Indeed, biological systems are homeody- namic because of their ability to dynamically self-organise at bifurcation points of their behaviour where they lose stability. Consequently, they exhibit diverse behaviour; in addition to monotonic stationary states, living systems display complex behaviour with all its emergent characteristics, i.e., bistable switches, thresholds, waves, gradients, mutual entrainment, and periodic as well as chaotic behaviour, as evidenced in cellular phenomena such as dynamic (supra)molecular organisation and flux coordination. These processes may proceed on different spatial scales, as well as across time scales, from the very rapid processes within and between molecules in membranes to the slow time scales of evolutionary change. It is dynamic organisation under homeodynamic conditions that make possible the organised complexity of life

The Argentinian-Uruguayan conflict over paper mills: ten years of a Latin American social-technical-environmental controversy

El artículo aborda retrospectivamente una controversia socio-tecno-ambiental en América Latina que en 2013 cumple una década de vigencia. Se trata del denominado “conflicto de las papeleras” entre Argentina y Uruguay, suscitado a raíz del proyecto de radicación de dos industrias productoras de pasta de celulosa sobre la costa oriental del río Uruguay. La percepción de los impactos sobre el ecosistema regional – en particular, sobre ese límite natural de soberanía compartida entre ambos países – generó una tenaz resistencia en la población argentina de la ciudad limítrofe de Gualeguaychú. En primer lugar, se describirán dos aspectos que justifican la condición de “caso paradigmático” con que suele calificarse al proceso: la magnitud de la oposición ciudadana y el carácter binacional del problema. En la siguiente sección se procederá a situar conceptualmente el conflicto en una confluencia de perspectivas teóricas, para analizar a continuación la experiencia de intervención social, las modalidades adoptadas en ausencia de instancias formales de participación, sus alcances y limitaciones intrínsecas. Se argumentará que los Estudios de Ciencia, Tecnología y Sociedad latinoamericanos aún tienen por delante el desafío de generar herramientas reflexivas y evaluativas más sensibles a las particularidades que asume la participación ciudadana en conflictos socio-tecno-ambientales en ese contexto, si pretenden que sus aportes cognitivos resulten útiles para el diseño de políticas públicas orientadas a promoverla y gestionarla.The article looks back at the so-called ‘paper mill conflict’ between Argentina and Uruguay. This very well-known Latin American social, technological, and environmental controversy began almost ten years ago, when two huge paper factories planned to establish their operations on the east coast of the Uruguay River. Residents of the adjacent Argentinean city of Gualeguaychú protested strongly against its potential impacts on the regional environment – particularly on the river, which is the natural boundary between both countries. In this project, we first describe two main features of the controversy to outline its relevance: the large scale of citizens’ reactions, and the cross-border nature of the problem. In the next section, we frame the context using conceptual tools provided by a number of theoretical perspectives; this is used to subsequently focus on the participatory experience promoted by the Environmental Civic Assembly of Gualeguaychú, which is usually regarded as a turning point in this kind of setting. We question the means, the scope and the limits of ‘civic resistance.’ In conclusion, we stress the need to develop context-sensitive frameworks that allow a better understanding of public participation in controversies in Latin-America. These frameworks provide not only conceptual but also useful tools for enabling public policies to outline more effective strategies devoted to promoting and managing public engagement and participation.Fil: Cortassa, Carina. Universidad Nacional de Entre Rios; ArgentinaFil: Andres, Gonzalo Dario. Universidad Nacional de Entre Rios; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wursten, Andrés. Universidad Nacional de Entre Rios; Argentin

Cometa e l’edizione di Omero in minuscola (A.P. 15.38)

The seven iambic lines by Cometas on his own text of Homer describe a complex editorial activity: the Byzantine scholar added punctuation and word separations, emended a number of passages, then had the text transliterated

Control and Regulation of Integrated Mitochondrial Function in Metabolic and Transport Networks

The pattern of flux and concentration control coefficients in an integrated mitochondrial energetics model is examined by applying a generalized matrix method of control analysis to calculate control coefficients, as well as response coefficients The computational model of Cortassa et al. encompasses oxidative phosphorylation, the TCA cycle, and Ca2+ dynamics. Control of ATP synthesis, TCA cycle, and ANT fluxes were found to be distributed among various mitochondrial processes. Control is shared by processes associated with ATP/ADP production and transport, as well as by Ca2+ dynamics. The calculation also analyzed the control of the concentrations of key regulatory ions and metabolites (Ca2+, NADH, ADP). The approach we have used demonstrates how properties of integrated systems may be understood through applications of computational modeling and control analysis