Direct power compensation in AC distribution networks with SCES systems via PI-PBC approach Gil González, Walter; Serra, Federico Martin; Montoya Giraldo, Oscar Danilo; Ramírez, Carlos Alberto; Orozco Henao, Cesar Here, we explore the possibility of employing proportional-integral passivity-based control (PI-PBC) to support active and reactive power in alternating current (AC) distribution networks by using a supercapacitor energy storage system. A direct power control approach is proposed by taking advantage of the Park?s reference frame transform direct and quadrature currents ( id and iq ) into active and reactive powers (p and q). Based on the open-loop Hamiltonian model of the system, we propose a closed-loop PI-PBC controller that takes advantage of Lyapunov?s stability to design a global tracking controller. Numerical simulations in MATLAB/Simulink demonstrate the efficiency and robustness of the proposed controller, especially for parametric uncertainties.

Argentina y Brasil: La alianza necesaria Merke, Mario Federico; Stuenkel, Oliver Desde el regreso de la democracia, la relación entre Argentina y Brasil nunca se percibió tan deteriorada como ahora que sufre las presiones sumadas de factores mundiales, regionales e internos. Si miramos el cuadro más amplio, el papel expansionista de China en la región y su creciente rivalidad con Estados Unidos colocan a Sudamérica en general, y a Argentina y Brasil en particular, ante un dilema que pone en riesgo la asociación estratégica. La contracción del comercio mundial y la incertidumbre que genera incrementa la aversión al riesgo en los negocios y reduce los márgenes de inserción internacional de Brasilia y Buenos Aires. El acuerdo comercial del Mercado Común del Sur (Mercosur) con la Unión Europea y otras opciones de acuerdos comerciales que se barajan abren la posibilidad de que se deteriore aún más esa relación. A este escenario se suma la inestabilidad política en Sudamérica y las reacciones dispares que genera en Argentina y Brasil en términos de cómo abordar los desafíos de la gobernanza regional. Mientras Brasil se muestra crítico del gobierno venezolano de Nicolás Maduro y distante de los foros regionales, Argentina intenta navegar por una ruta intermedia entre Maduro y Juan Guaidó, y trata de reconstruir de algún modo la concertación regional...

Lenguaje denso y apertura: Otra vindicación de la poesía como órgano del conocimiento; Dense language and opening: Another vindication of poetry as an organ of knowledge Blanco Ilari, Juan Ignacio Este trabajo se enmarca dentro de las innumerables vindicaciones de la poesía. Comienza con el desarrollo de las cuatro características del “lenguaje poético” en tanto “lenguaje denso”. La figuratividad o metaforicidad, su alusividad, la identidad forma-contenido y el realismo poético. En el segundo apartado se analizan estas características a la luz de las categorías de “significatividad” y de “interpretante”. La ontología heideggeriana y la semiótica peirceana enriquecen el concepto de lenguaje denso y aclaran su poder epistémico. Finalmente, analizo algunos aspectos que Nietzsche, en su período retórico (1869-1874), elabora sobre el lenguaje, y que prefiguran y amplían la noción de lenguaje denso. Me centro allí en la idea que todo lenguaje es, en su origen, retórica, y en el modo en que el proceso comunicativo atenta contra dicho origen. Me interesan, en particular, las nociones de “fijación”, “olvido” y “restauración”.; This work is framed within the innumerable vindications of poetry. It begins with the development of the four characteristics of “poetic language” as “dense language”. Figurativity or metaphoricity, its allusiveness, form-content identity, and poetic realism. In the second section, these characteristics are analyzed in the light of the categories of “significance” and “interpretant”. The heideggerian ontology and the peircean semiotics enrich the concept of dense language and clarify its epistemic power. Finally, I analyze some aspects that Nietzsche, is his rhetorical period (1869-1874), elaborates on language, aspects that prefigure and expand the notion of dense language. I focus there on the idea that all language is, in its origin, rhetoric, and in the way in which the communicative process attacks that origin. I am particularly interested in the notions of “fixation”, “forgetting” and “restoration”.

El acontecimiento Sanders Plot, Martin Fernando Bernie Sanders no es solamente el nombre de un candidato y dirigente político estadounidense. Bernie Sanders es el nombre de un acontecimiento —y ese acontecimiento es, además, el reverso del anverso de otro acontecimiento, uno que también tiene nombre propio y se llama Donald Trump. Ambos acontecimientos irrumpieron en la vida política norteamericana en las elecciones primarias de los partidos demócrata y republicano de 2016 y aún no han cesado de generar consecuencias de relevancia.

Sobre los inicios de un revisionismo filosófico en Argentina y sus derivas políticas: Homero Guglielmini, Saúl Taborda y Carlos Astrada; On the beginnings of a philosophical revisionism in Argentina and its political commitments: Homero Guglielmini, Saúl Taborda, and Carlos Astrada Domínguez Rubio, Lucas Manuel El presente artículo analiza los principales textos que con distintos intereses ideológicos funcionaron como iniciadores de un particular ensayismo filosófico organizacionista y anti-liberal en la Argentina desde espacios académicos y universitarios. Sus autores, Saúl Taborda (1885-1943), Homero Guglielmini (1903-1968) y Carlos Astrada (1894-1971) tuvieron una trayectoria teórica y política en buena medida común. Primero desarrollaron sus textos en términos nietzscheanos y soreleanos. Más tarde se interesaron en el romanticismo alemán y la obra de Heidegger. En este arco, desde la década de 1920 cuando estuvieron a cargo de incipientes revistas filosóficas y vanguardistas hasta el momento en que Astrada y Guglielmini se convirtieron de en dos de las más importantes plumas oficialistas del gobierno de Juan Domingo Perón, estos autores mantuvieron sus intereses anti-iluministas y anti-liberales, con los cuales se opusieron a los estudios históricos como modo de indagación. Frente a ellos, desarrollaron un ensayismo filosófico no histórico que el presente artículo periodiza y caracteriza en oposición al más estudiado revisionismo histórico. A diferencia de estos últimos, los filósofos no reaccionaron frente a las continuas olas inmigratorias, sino más bien a los proyectos políticos foráneos. Se enfocaron principalmente en la figura del gaucho, y no en la de Rosas, y propusieron una reivindicación nocatólica del hispanismo. Pero, principalmente, ellos argumentaron contra el individualismo liberal y buscaron pensar herramientas teóricas a favor de un sujeto político colectivo.; This article analyzes the theoretical and ideological interests of the first philosophical essays in Argentina from an intellectual-history perspective. Saúl Taborda (1885-1943), Homero Guglielmini (1903-1968) and Carlos Astrada (1894-1971) had similar theoretical and political trajectories. From the 1920s, when they were in charge of incipient philosophical and avant-garde magazines, they were influenced by the writings of Nietzsche and Sorel. Later, they were interested in German romanticism and Heidegger's work, in the moment when Astrada and Guglielmini became two of the most important intellectuals of Juan Domingo Perón's government. While the so-called historical revisionism has received a remarkable attention, we only have a few works on this philosophical revisionism in Argentina. It is necessary, thus, to differentiate these early revisionist writings from their counterparts dedicated to history. The philosophers did not react to the continuous waves of immigration but rather to liberal political innovations taken as "foreign ideas". They focused especially on the figure of the gaucho and proposed a non-Catholic reading of Hispanicism. In a nutshell, they argued against individualism and forth theoretical tools to think a collective subject. Therefore, this work describes a theoretical trajectory that is well known at the European level, ranging from vitalist and aestheticist irrationalism to nationalist and strongly anti-individualist organisationalist positions.

Online self-powered Cr(VI) monitoring with autochthonous Pseudomonas and a bio-inspired redox polymer Lazzarini Behrmann, Irene Constanza; Grattieri, Matteo; Minteer, Shelley D.; Ramirez, Silvana A.; Vullo, Diana Lia The assessment of water quality is critical to implement preventive and emergency interventions aimed to limit/avoid environmental contamination and human exposure to toxic compounds. While established high-resolution techniques allow quantitative and qualitative determination of contaminants, their widespread application is not feasible due to cost, time, and need for trained personnel. In this context, the development of easy-to-implement approaches for preliminary detection of contaminants is of the utmost importance. Herein, a portable self-powered microbial electrochemical sensor enabling online monitoring of Cr(VI) is reported. The biosensor employs a bio-inspired redox mediating system to allow extracellular electron transfer between a bacterial isolate from chromium-contaminated environments and the electrode, providing a clear response to Cr(VI) presence. The biosensor shows good linearity (R2 = 0.983) and a limit of detection of 2.4 mg L−1 Cr(VI), with a sensitivity of 0.31 ± 0.02 μA cm−2 mgCr(VI)−1 L. The presented microbial bioanode architecture enhanced biosensor performance thanks to the improved “electrical wiring” between biological entities and the abiotic electrode surface. This approach could be easily implemented in engineered electrode surfaces, such as paper-based multi-anodes that maximize bacterial colonization, further improving biosensor response.

On the behavior of rainfall maxima at the eastern Andes Hierro, Rodrigo Federico; Burgos Fonseca, Yuditsabet; Ramezani Ziarani, M.; Llamedo Soria, Pablo Martin; Schmidt, T.; de la Torre, Alejandro; Alexander, Pedro Manfredo In this study, we detect high percentile rainfall events in the eastern central Andes, based on Tropical Rainfall Measuring Mission (TRMM) with a spatial resolution of 0.25 × 0.25°, a temporal resolution of 3 h, and for the duration from 2001 to 2018. We identify three areas with high mean accumulated rainfall and analyze their atmospheric behaviour and rainfall characteristics with specific focus on extreme events. Extreme events are defined by events above the 95th percentile of their daily mean accumulated rainfall. Austral summer (DJF) is the period of the year presenting the most frequent extreme events over these three regions. Daily statistics show that the spatial maxima, as well as their associated extreme events, are produced during the night. For the considered period, ERA-Interim reanalysis data, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) with 0.75° x0.75° spatial and 6-hourly temporal resolutions, were used for the analysis of the meso- and synoptic-scale atmospheric patterns. Night- and day-time differences indicate a nocturnal overload of northerly and northeasterly low-level humidity flows arriving from tropical South America. Under these conditions, cooling descending air from the mountains may find unstable air at the surface, giving place to the development of strong local convection. Another possible mechanism is presented here: a forced ascent of the low-level flow due to the mountains, disrupting the atmospheric stratification and generating vertical displacement of air trajectories. A Principal Component Analysis (PCA) in T-mode is applied to day- and night-time data during the maximum and extreme events. The results show strong correlation areas over each subregion under study during night-time, whereas during day-time no defined patterns are found. This confirms the observed nocturnal behavior of rainfall within these three hotspots.

The role of environmental, geographical, morphometric and spatial variables on plankton communities in lakes of the arid Patagonian plateaus Porcel, Elisa María Sol; Chaparro, Griselda Noemí; Marinone, María Cristina; Saad, Juan Francisco; Lancelotti, Julio Lucio; Izaguirre, Irina Species diversity is one of the most informative community metrics and is influenced by regional and local factors. We studied the spatial patterns of taxonomic and functional phyto- and zooplankton diversity in 33 lakes from two basaltic plateaus of the arid Patagonia. The aims of our study were to evaluate α, β and γ taxonomic diversity of phyto- and zooplankton; to assess the influence of environmental, spatial, geographical and morphometric factors on phyto- and zooplankton communities and to compare the influence of these variables on the taxonomic and functional composition. β1-diversity (within plateaus) was the major component for phytoplankton, rotifers andmicrocrustaceans taxonomic regional diversities. Planktonic communities were mainly constrained by macrophytes, fish, conductivity, dissolved organic carbon, altitude and spatial factors. The high dispersion of small individuals within plateaus tends to homogenize these communities, as indicated by null model results and the high explanation of fine-scale spatial factors in variation partitioning. This knowledge contributes to explaining the diversity patterns of planktonic communities of these valuable environments and to develop conservation strategies, considering both environmental heterogeneity and spatial effects.

The first mammal assemblages from the Malargüe Group: Implications for the Paleogene evolution of the northern Neuquén Basin (Argentina) Vera, Bárbara Soledad; Tunik, Maisa Andrea; Cerdeño Serrano, Maria Esperanza We present two new Paleogene fossiliferous sites that provide the first mammal remains for the Malargüe Group in the Neuquén basin of southeastern Mendoza Province, Argentina. Identified taxa from Agua de Flores-Agua de Isaac: Kibenikhoria sp., Oldfieldthomasiidae indet., Henricosborniidae indet., and a large Notoungulata probably related to the Isotemnidae. Taxa from Liu Malal: cf. Kibenikhoria and Notopithecidae gen. et sp. nov. Based on facies composition and geological distribution, we consider that the Cenozoic deposits from these fossiliferous localities correspond to the already defined Puesto Fortunata Formation. This unit is correlated to the Coihueco Formation, the top of the Malargüe Group in the northern Neuquén basin, and its mammal content supports the proposed hiatus between the ~40 Ma and 20 Ma based on chronostratigraphy. The presence of Kibenikhoria in the local faunas of southeastern Mendoza extends the geographic range of this genus so far known in Patagonia to central-west areas of Argentina and supports an early-middle Eocene age for the fossil-bearing levels of the Puesto Fortunata Formation.

Albendazole solid dispersions against alveolar echinococcosis: a pharmacotechnical strategy to improve the efficacy of the drug Fabbri, Julia; Pensel, Patricia Eugenia; Albani, Clara Maria; Lopez, Lurdes Milagros; Simonazzi, Analía; Bermudez, José María; Palma, Santiago Daniel; Elissondo, María Celina Alveolar echinococcosis is a neglected parasitic zoonosis caused by Echinococcus multilocularis. The pharmacological treatment is based on albendazole (ABZ). However, the low water solubility of the drug produces a limited dissolution rate, with the consequent failure in the treatment of the disease. Solid dispersions are a successful pharmacotechnical strategy to improve the dissolution profile of poorly water-soluble drugs. The aim of this work was to determine the in vivo efficacy of ABZ solid dispersions using poloxamer 407 as a carrier (ABZ:P407 solid dispersions (SDs)) in the murine intraperitoneal infection model for secondary alveolar echinococcosis. In the chemoprophylactic efficacy study, the ABZ suspension, the ABZ:P407 SDs and the physical mixture of ABZ and poloxamer 407 showed a tendency to decrease the development of murine cysts, causing damage to the germinal layer. In the clinical efficacy study, the ABZ:P407 SDs produced a significant decrease in the weight of murine cysts. In addition, the SDs produced extensive damage to the germinal layer. The increase in the efficacy of ABZ could be due to the improvement of water solubility and wettability of the drug due to the surfactant nature of poloxamer 407. In conclusion, this study is the basis for further research. This pharmacotechnical strategy might in the future offer novel treatment alternatives for human alveolar echinococcosis.

An experimental approach to study the red blood cell dynamics in a capillary tube by biospeckle laser Toderi Cicchini, Martín Alejandro; Riquelme, Bibiana Doris; Galizzi, Gustavo Ernesto In this study we investigated the human red blood cell (RBC) dynamics by means of biospeckle laser analysis. Blood samples from healthy donors were introduced in a 0.8 mm internal diameter capillary tube, and illuminated with a He-Ne laser in order to obtain the biospeckle pattern from both side and forward scattered light. Experiments were carried out for different concentrations of red blood cells in plasma, from 25% to 50%. Biospeckle parameters such as Correlation Coefficient and Inertia Moment, were calculated for different frequency bandwidths in order to assess their sensitivity and versatility. A filter based on the Discrete Wavelet Transform was used to decompose the registered sample activity. A relation between Inertia Moment and the RBCs to plasma volume ratio was observed. The Correlation Index that measures the level of correlation of biospeckle images was defined and analyzed. This work inquires in a technique that is suitable for the development of novel non-invasive optical tools for clinical diagnosis in vascular pathologies.

Biología reproductiva de Bothrops alternatus en un área templada de América del Sur: ciclo reproductivo masculino; Reproductive biology of Bothrops alternatus in a South America template area: male reproductive cycle Bellini, Gisela Paola; Arzamendia, Vanesa; Alberto, Diana Mariel; Giraudo, Alejandro Raul La yarará grande Bothrops alternatus es una especie de serpiente venenosa ampliamente distribuida y abundante en el área templada de América del Sur. Sin embargo el conocimiento sobre su biología reproductiva es mayormente conocido por datos de poblaciones brasileñas, existiendo escasos datos de las poblaciones argentinas. La historia de vida de las serpientes está influenciada por factores ecológicos como las variaciones regionales en las estaciones climáticas, generando diferencias en la biología reproductiva entre las poblaciones de diferentes regiones. Presentamos el ciclo reproductivo masculino de B. alternatus en su límite de distribución austral, basado en datos morfo-anatómicos e histológicos. El volumen testicular varió a lo largo de las estaciones, coincidiendo su aumento y disminución con el aumento y disminución de la temperatura. Sin embargo, las medidas morfo-anatómicas no mostraron todos los diferentes estadios por los que atraviesa el testículo de B. alternatus. En primavera los testículos estuvieron en recrudescencia y en verano comenzó la espermiogénesis que se extendió hasta el inicio del otoño (abril). La regresión testicular comenzó en mayo (otoño) y en invierno el epitelio seminífero de los testículos se retrae totalmente, encontrándose en regresión total hacia julio y hasta comienzos de septiembre (invierno). Los machos de B. alternatus estuvieron reproductivamente activos durante la primavera / verano y reproductivamente inactivos durante el otoño / invierno, determinando un ciclo reproductivo estacional. No obstante, se encontraron espermatozoides en los túbulos deferentes a lo largo de todos los meses del año. Con este estudio, aportamos evidencia para apoyar la importancia del enfoque microscópico para los estudios de los ciclos reproductivos. Finalmente, discutimos la sincronización del ciclo reproductivo masculino con el ciclo femenino en la población más austral de B. alternatus.; The pitviper Bothrops alternatus is one of the most widely distributed and abundant venomous snake species in the South America template area. However, knowledge about their reproductive biology is mostly known for data from Brazilian populations, finding few data for the Argentine populations. The life history of snakes is influenced by ecological factors such asregional variations in climatic seasons, generating differences in reproductive biology between populations in different regions. We present the male reproductive cycle of B. alternatus at its southern distribution limit, based on morpho-anatomical and histological data. The testicular volume varied throughout the seasons, coinciding its increase and decrease with the increaseand decrease in temperature. However, the morpho-anatomical measures did not show all the different stages through which the B. alternatus testicle passes. In spring the testicles were in recrudescence and in summer began the spermiogenesis that extended until the beginning of autumn (April). Testicular regression began in May (autumn) and in winter the seminiferous epithelium of the testicles retracts completely, being in total regression towards July and until the beginning of September (winter). Males of B. alternatus were reproductively active during spring / summer and reproductively inactive during autumn / winter, determining a seasonal reproductive cycle. However, sperm were found in the deferens ducts throughout all the year.With this study, we provide evidence to support the importance of the microscopic approach for studies of reproductive cycles. Finally, we discuss the synchronization of the male reproductive cycle with the female reproductive cycle in the southernmost population of B. alternatus.

Optical and electrical optimization of all-perovskite pin type junction tandem solar cells Soldera, Marcos Maximiliano; Koffman Frischknecht, Alejandro; Taretto, Kurt Rodolfo A definitive breakthrough of perovskite solar cells towards large scale industrialization is believed to be the demonstration of higher efficiencies than conventional silicon technology, suggesting the exploration of perovskite tandem cell configurations. Since high efficiency tandem solar cells require careful optimization of photoactive as well as contact and additional functional layers, we propose an optical-electrical model to obtain the optimum layer thicknesses and the attainable electrical output parameters of two-terminal perovskite-perovskite tandem solar cells. The optical model takes into account the coherent propagation of light through the layer stack comprising two perovskite semiconductors and the corresponding contact layers, while the electrical model assumes two series-connected analytical current/voltage equations for pin solar cells. This model allows to assess the impact of the main physical parameters on each perovskite layer without requiring the high specificity needed in more rigorous numerical simulations. Efficiencies above 34 % are predicted considering available perovskites with non-optimum bandgap and contact materials already proven in efficient laboratory solar cells. The requisite to attain such efficiencies is that recombination at the interfaces between the perovskite and contact materials is kept low in both bottom and top cells. Furthermore, within the assumption of non-optimum bandgaps of currently available perovskites, the simulation results suggest that efficiencies around 37 % are possible when adopting contact materials with smaller absorption, more adequate refraction indices, and lower resistivity.

Anti-Quorum Sensing Activity of Argentinean Honey and Effect of pH on Main Flavonoids Chiappe, Cristina Susana; Iurlina, Miriam Ofelia; Saiz, Amelia Ivone In this study, the anti-QS activity of regional floral honey from the southeast region of Argentina was investigated using the bacterial model Chromobacterium violaceum. In addition, the anti-QS activity of quercetin, myricetin and luteolin was evaluated in an acidic medium. Two of the tested honey samples had the capacity to exert a notable anti-QS effect on C. violaceum. The effect of quercetin on the anti-QS activity at pH 5.8 was higher than myricetin and luteolin. The results obtained from the identification of quercetin, myricetin and luteolin of the honey extracts by High-Performance Liquid Chromatography (HPLC) showed that quercetin was the main flavonoid followed by myricetin and luteolin. It was observed that honey with high values of quercetin and high value of free acidity, exerted a greater effect on the inhibition of QS. Thus, we can conclude that an umbral value of pH seems to be necessary to increase the anti-QS activity of quercetin.

Los monstruos de la razón Vignale, Silvana Paola Hay algo de precipitado y riesgoso en intentar pensar ?en movimiento? sobre algo que está sucediendo. En ese sentido, es necesario siempre hacerlo desde los acontecimientos y desde las prácticas, y no desde conceptos que en un momento comienzan a funcionar como universales; y en ejercicio crítico del pensamiento, no intentar dar respuestas, sino delimitar cuál es hoy nuestro problema. En ese caso, conviene salir del único registro de la excepcionalidad como paradigma de la gubernamentalidad biopolítica, así como del de la defensa de las libertades formales que reaviva la fobia al Estado. Puede que estén cambiando las condiciones de posibilidad de nuestra experiencia histórica, aunque aún no sepamos cuál será esa deriva, y que la coincidencia temporal con los acontecimientos nos obscurezca en qué direcciones eso esté cambiando. Sin embargo, eso no quiere decir que tengamos que quedarnos impávidos, nos insta a una actitud de alerta.

Cretaceous tetrapod tracks from Italy: a treasure trove of exceptional biodiversity Petti, Fabio Massimo; Antonelli, Mateo; Citton, Paolo; Mariotti, Nino; Petruzzelli, Marco; Pignatti, Johannes; D’Orazi Porchetti, Simone; Romano, Marco; Sacchi, Eva; Sacco, Enrico; Wagensommer, Alexander After about thirty years of investigation, the Cretaceous tetrapod track record from Italy has proved to be a ‘Rosetta Stone’ for improving understanding of the palaeogeographical and palaeoenvironmental evolution of the peri-Adriatic area. In the present contribution, we summarize current knowledge and diferent interpretations proposed on the basis of twelve ichnosites from northern, central and southern Italy. The tetrapod track record is represented by few ichnosites in the earliest Cretaceous, with the bulk of the record reported from carbonate platform deposits of the Aptian-Cenomanian interval and, in the Late Cretaceous, from a extensive-tracksite in Apulia preserving thousands of dinosaur footprints. On the whole, the ichnological diversity documented by the material indicates a high diversity of trackmakers, among which are sauropods, diferent kinds of theropods, ankylosaurs and hadrosaurs. The persistent occurrence of dinosaur footprints at diferent stratigraphic levels produced significant questions and constituted a dramatic constraint for the understanding of palaeogeographical and geodynamical evolution of the Mediterranean area during the Mesozoic, suggesting new and diferent interpretations that challenged previous reconstructions.

Extranuclear structural components that mediate dynamic chromosome movements in yeast meiosis Lee, Chih Ying; Bisig, Carlos Gaston; Conrad, Michael M.; Ditamo, Yanina; Previato de Almeida, Luciana; Dresser, Michael E.; Pezza, Roberto J. Telomere-led rapid chromosome movements or rapid prophase movements direct fundamental meiotic processes required for successful haploidization of the genome. Critical components of the machinery that generates rapid prophase movements are unknown, and the mechanism underlying rapid prophase movements remains poorly understood. We identified S. cerevisiae Mps2 as the outer nuclear membrane protein that connects the LINC complex with the cytoskeleton. We also demonstrate that the motor Myo2 works together with Mps2 to couple the telomeres to the actin cytoskeleton. Further, we show that Csm4 interacts with Mps2 and is required for perinuclear localization of Myo2, implicating Csm4 as a regulator of the Mps2-Myo2 interaction. We propose a model in which the newly identified functions of Mps2 and Myo2 cooperate with Csm4 to drive chromosome movements in meiotic prophase by coupling telomeres to the actin cytoskeleton.

Obtención de espectros usando un smartphone en la clase de Física Szigety, Esteban Guillermo; Bernal, Luis Jaime; Bilbao, Luis Ernesto; Pérez, Gabriel Horacio Este artículo presenta los fundamentos para convertir un teléfono inteligente (o smartphone) en un espectrómetro casero. Utilizando un Compact Disc Digital Audio y una ranura ubicada adecuadamente se puede observar, entre otros, el espectro de emisión de una lámpara fluorescente compacta. Además, en este trabajo se incluyen los pasos metodológicos para medir las líneas de Fraunhofer del Sol de mayor ancho espectral. La propuesta está pensada para llevar adelante una clase práctica de espectros lumínicos tanto en instituciones de educación media como así también en cursos introductorios de física universitaria.; This article presents the basics for converting a smartphone as a home spectrometer. Using a Compact Disc Digital Audio and a properly located slot, the emission spectrum of a compact fluorescent lamp and other sources can be observed. This work includes the methodological steps to measure the Fraunhofer's lines of the sun with the greatest spectral width. The proposal is designed to carry out a practical class of light spectra both from institutions of secondary education as well as in introductory courses in university physics.

Las resistencias a las "relaciones carnales" con Estados Unidos (1990-2015); The resistance to ‘carnal relations’ with the United States (1990-2015) Morgenfeld, Leandro Ariel Desde que asumió, en 1989, Menem planteó un giro en el vínculo con Estados Unidos, priorizando las "relaciones carnales", denominación que se popularizó a partir de una frase del canciller Guido Di Tella. Si bien logró un cierto consenso en esa política exterior más alineada con Washington, la misma tuvo sus detractores internos. En este artículo se analizan las resistencias a esa orientación en tres momentos claves: las expresiones de rechazo a las visitas de Bush (1990) y Clinton (1997) y las movilizaciones contra la invasión a Irak (2003) y las acciones contra Bush Jr y el ALCA (2005). En ese período de 15 años, en el que se produjo el inicio, auge y declive de ese estrecho alineamiento con la principal potencia, fueron importantes las expresiones de resistencia, que en general se soslayan o minimizan en los estudios de la historia de la política exterior argentina.; Since he took office in 1989, Carlos Saúl Menem proposed a new orientation in the link with the United States, prioritizing the “carnal relations”, a name that was popularized by a phrase of Foreign Minister Guido Di Tella. Although that foreign policy, more aligned with Washington, achieved a certain consensus, it had its internal detractors. In this article the resistance to this orientation is analyzed in three key moments: the expressions of rejection of the visits of Bush (1990) and Clinton (1997) and the protests against the invasion of Iraq (2003) and the actions against Bush Jr. and the FTAA (2005). In this period of 15 years, in which there was the beginning, rise and decline of this close link with the main foreign power, the expressions of resistance were important, despite being generally ignored or minimized in the studies of the history of Argentine foreign policy.

Arabidopsis thaliana SURFEIT1-like genes link mitochondrial function to early plant development and hormonal growth responses Gras, Diana Ester; Mansilla, Natanael; Rodriguez, Carina; Welchen, Elina; Gonzalez, Daniel Hector Mutations in SURFEIT1 (SURF1) genes affect cytochrome c oxidase (COX) levels in different prokaryotic and eukaryotic organisms. In this work, we report that Arabidopsis thaliana has two genes that potentially encode SURF1 proteins, as a result of a duplication that took place in Brassicaceae. Both genes encode mitochondrial proteins and mutation in AtSURF1a causes embryonic lethality. Mutation in AtSURF1b, instead, causes defects in hypocotyl elongation under growth-stimulating conditions, such as low light intensity, increased ambient temperature and incubation with glucose. Mutants in AtSURF1b show reduced expression of the auxin reporter DR5:GUS and increased levels of the gibberellin reporter GFP-RGA, suggesting that auxin and gibberellin homeostasis are affected. In agreement, growth defects caused by AtSURF1b mutation can be overcome by treatment with indole-3-acetic acid and gibberellin A3, and also by increasing expression of the auxin biosynthesis gene YUC8 or the transcription factor PIF4, which shows lower abundance in AtSURF1b-deficient plants. Mutants in AtSURF1b display lower COX levels, higher alternative oxidase and superoxide levels, and increased expression of genes that respond to mitochondrial dysfunction. Decreased hypocotyl growth and DR5:GUS expression can be reversed by treatment with reduced glutathione, suggesting that redox changes, probably related to mitochondrial dysfunction, are responsible for the effect of AtSURF1b deficiency on hormone responses. The results indicate that changes in AtSURF1b affect mitochondrial function and the production of reactive oxygen species, which, in turn, impinges on a growth regulatory circuit that involves auxin, gibberellins and the transcription factor PIF4.