Ciencia y Tecnología

Efectos de los bordes de caminos y las plantas invasoras sobre la vegetación en pie y el banco de semillas en matorrales norpatagónicos

CONICET Digital -

Efectos de los bordes de caminos y las plantas invasoras sobre la vegetación en pie y el banco de semillas en matorrales norpatagónicos Chichizola, Giselle Ailin; Gonzalez, Sofía Ariadna; Rovere, Adriana La construcción de caminos genera impactos ambientales en los ecosistemas que atraviesan, al fragmentar y transformar los hábitats. Esto afecta el ensamble de especies en áreas degradadas y contribuye a la introducción y al aumento de especies de plantas exóticas e invasoras. La introducción de especies invasoras cambia la abundancia y la composición de especies nativas, representando una amenaza para la biodiversidad a nivel global. El objetivo de este trabajo fue analizar el ensamble de la vegetación en pie y el banco de semillas, e identificar las especies invasoras en taludes de desmonte en bordes de camino de matorrales de Nothofagus antarctica en el noroeste patagónico. Se analizó la composición, la riqueza, la diversidad y la abundancia de especies exóticas y nativas, y de grupos funcionales de la vegetación en pie y en el banco de semillas en taludes y áreas de referencia cercanas. Los taludes presentaron diferente composición florística, con menor cobertura de la vegetación y densidad de semillas de especies totales, menor riqueza y cobertura de especies nativas, y menor densidad de semillas de especies exóticas que las áreas de referencia. La similitud entre la vegetación en pie y el banco fue alta para las especies exóticas. En la vegetación de los taludes predominaron las hierbas, las gramíneas anuales/bianuales y las perennes exóticas invasoras, y las hierbas, las gramíneas perennes y los arbustos nativos; no se encontraron semillas de arbustos. La presencia de especies exóticas en los taludes puede deberse a las condiciones de los micrositios y a los rasgos de las especies que los colonizan, como a la capacidad de formar banco de semillas, la alta producción de semillas y la forma y el ciclo de vida. Este trabajo en matorrales del noroeste patagónico mostró que los bordes de camino y sus áreas cercanas albergan especies exóticas potencialmente invasoras, y que es importante identificarlas tempranamente para controlarlas.

Asparagaceae Juss (Agavoideae)

CONICET Digital -

Asparagaceae Juss (Agavoideae) Martinez Carretero, Eduardo Enrique; Bonjour, Lorena de Jesús; Ontivero, Marcela del Valle; Ganci, Carmelo En las zonas urbanas del centro-oeste de Argentina se cultivan como ornamentales especies principalmente de los géneros. Asparagus, Agave, Beaucarnea, Chlorophytum Dasylirion, Ruscus, Dracaena (Sansevieria) y Yucca. Se presenta la clave de los géneros más comunes.

Halophytaceae Soriano

CONICET Digital -

Halophytaceae Soriano Martinez Carretero, Eduardo Enrique Halophytum Speg. Familia y género monotípico. Herbáceas, monoicas. Hojas carnosas sin estípulas. Flores imperfectas. Flores estaminadas en espigas; perigonio con 4 tépalos libres; estambres 4, alternitépalos. Flores pistiladas alojadas en cavidades del tallo. Ovario súpero. Utrículos reunidos en un sincarpo duro.

Transformer-Based Representation of Organic Molecules for Potential Modeling of Physicochemical Properties

CONICET Digital -

Transformer-Based Representation of Organic Molecules for Potential Modeling of Physicochemical Properties Perez Correa, Ignacio; Giunta, Pablo Daniel; Mariño, Fernando Javier; Francesconi, Javier Andres In this work, we study the use of three configurations of an autoencoder neural network to process organic substances with the aim of generating meaningful molecular descriptors that can be employed to develop property prediction models. A total of 18,322,500 compounds represented as SMILES strings were used to train the model, demonstrating that a latent space of 24 units is able to adequately reconstruct the data. After AE training, an analysis of the latent space properties in terms of compound similarity was carried out, indicating that this space possesses desired properties for the potential development of models for forecasting physical properties of organiccompounds. As a final step, a QSPR model was developed to predict the boiling point of chemical substances based on the AE descriptors.5276 substances were used for the regression task, and the predictive ability was compared with models available in the literature evaluated on the same database. The final AE model has an overall error of 1.40% (1.39% with augmented SMILES) in the prediction of the boiling temperature, while other models have errors between 2.0 and 3.2%. This shows that the SMILES representation is comparable and even outperforms the state-of-the-art representations widely used in the literature.

El razonamiento clínico y la inteligencia artificial

CONICET Digital -

El razonamiento clínico y la inteligencia artificial; Clinical reasoning and artificial intelligence; Raciocínio clínico e inteligência artificial Cuestas, Eduardo Tanto la literatura científica como los medios de comunicación no especializados han expuesto que la inteligencia artificial (IA) podría igualar o incluso superar a la inteligencia humana en las tareas de diagnóstico clínico. Analizaremos aquí las diferencias en la forma en que los médicos y la IA abordan el diagnóstico para argumentar que el razonamiento humano pervivirá y continuará siendo necesario para efectuar diagnósticos acertados, creativos y éticamente responsables dentro del contexto personal de cada paciente entendido como un ser social único e irrepetible. Los diagnósticos de la IA se basan en algoritmos de aprendizaje automático que son teóricamente “inteligentes” como para manejar problemas difíciles y complejos. Estos algoritmos dependen a su vez de la inteligencia y de la acción humana para su creación y entrenamiento. En este campo se han logrado avances sustanciales gracias a las redes neuronales, una familia de métodos de aprendizaje automático, y particularmente de las redes neuronales profundas...

Notas dispersas sobre las imágenes sadeanas

CONICET Digital -

Notas dispersas sobre las imágenes sadeanas; Scattered Notes on Sadean Images Molina, Cristian Julio En este trabajo, abordamos la problemática de las imágenes sadeanas como condensadoras de una serie de cuestiones. En principio, como reverberaciones de un modo de lo sensible; es decir, destellos durante la lectura que las hacen reconocibles y nominables como tales y que tienen una insistencia transtemporal y transterritorial. En segundo lugar, como aquellas donde se hacen evidentes tensiones respecto de los dispositivos sexogenéricos, feministas y culturales en temporalidades disímiles. En tercer lugar, como dispersiones de heterogeneidades que, sin embargo, se constelan. Esto supone un método de lectura y escritura que advierta e inscriba los destellos efímeros de estas, sin una relación lineal en el tiempo y, a su vez, sin una argumentación progresiva y unívoca, sino cortada y reverberante, donde se produzca una reflexión sobre la imagen en sí y donde se analicen imágenes sadeanas provenientes de diversos contextos temporo-espaciales, de manera efímera, en tanto múltiples notas que se vinculan durante la lectura.; We work the Sadean image’s problem as condensers of diferent issues. First, as reverberations of a sensible way; that is, flashes that occur during reading that make them recognizable and nameable and that have a transtemporal and transterritorial consistency. Second, they show tensions regarding sex, gender, feminist and cultural devices in dissimilar temporalities. Third, as dispersions of heterogeneities that, however, constellate. This supposes a method of reading and writing that notices and inscribes their ephemeral flashes, without a linear relationship in time and, in turn, without a progressive and univocal argumentation, but cut and reverberant, where a reflection on the image is produced in itself and where Sadean images from various temporal-spatial contexts are analyzed, in an ephemeral way, as different notes that are linked during reading.

Experiencias de personas travestis/trans en el acceso a la salud mental integral en Córdoba, Argentina durante el período 2021-2023, desde un enfoque transfeminista-nuestroamericano

CONICET Digital -

Experiencias de personas travestis/trans en el acceso a la salud mental integral en Córdoba, Argentina durante el período 2021-2023, desde un enfoque transfeminista-nuestroamericano; Experiences of Transgenders/Trans People in the Access to Comprehensive Mental Health in Córdoba, Argentina During the Period 2021-2023, from a Transfeminist-Latin American Approach Artazo, Gabriela Cristina El presente artículo se propone analizar el acceso de la población travesti/trans a prestaciones de salud mental integral haciendo foco en servicios del primer nivel y en la atención del consumo problemático de sustancias. El clivaje analítico se centra en la incidencia de las prestaciones de salud mental integral en las posibilidades de inclusión laboral de personas travesti/trans al circuito formal de empleo. El análisis del problema se realiza a través de una etnografía situada, relacionando el acceso a estos dispositivos desde la perspectiva de la población y sus agentes durante el período 2021-2023, en la ciudad de Córdoba.; The aim of this article is to analyze the access of the transgender/trans population to comprehensive mental health services, focusing on first level services and care for problematic substance use. The analytical division focuses on the incidence of comprehensive mental health services on the possibilities of labor inclusion of transgenders/trans people in the formal employment circuit. The analysis of the problem is carried out through a situated ethnography, relating the access to these devices from the perspective of the population and its agents during the period 2021-2023, in the city of Córdoba.

Caracterización de ocurrencia en distintos horarios de condiciones meteorológicas óptimas para la aplicación de agroquímicos en el Sudeste de Buenos Aires

CONICET Digital -

Caracterización de ocurrencia en distintos horarios de condiciones meteorológicas óptimas para la aplicación de agroquímicos en el Sudeste de Buenos Aires; Characterization of occurrence of optimal meteorological conditions for the application of agrochemicals in the southeast of Buenos Aires Platz, Juan Pedro; Tourn, Santiago Néstor; Echarte, Laura; Cendoya, María Gabriela Las aplicaciones de agroquímicos son prácticas comunes utilizadas para proteger y nutrir cultivos que incluyen productos fitosanitarios y fertilizantes. El resultado de una correcta aplicación implica el logro del efecto buscado procurando reducir al mínimo las pérdidas de producto en función de la protección de la salud humana y el ambiente. El objetivo de este trabajo fue caracterizar la probabilidad de ocurrencia de condiciones meteorológicas óptimas para lograr mejor calidad de aplicaciones. Se recopiló información registrada por una estación meteorológica automática en la Estancia La Morocha (Balcarce, provincia de Buenos Aires) para la serie de años desde 2006-2018. Los resultados indicaron que las probabilidades de ocurrencia de condiciones óptimas (velocidad máxima del viento: 4 m s-1, temperatura del aire límite de 30 °C y 20% humedad relativa mínima) son inferiores al 50% en prácticamente todos los trimestres y horarios. Desde la 0 h hasta las 7 h de la mañana estas probabilidades se mantienen entre 30% y 50%, siendo en el período otoñal más cercana al 50%. Por otra parte, en el rango horario de 11 h a 17 h, las condiciones óptimas para la aplicación se presentaron en menos del 15% de los días en todos los trimestres, excepto por el período otoñal donde alcanzó el 20%. En conclusión, en el sudeste bonaerense las condiciones meteorológicas con condiciones adecuadas para la aplicación de fitosanitarios y fertilizantes presentan, en general, una baja frecuencia de días por trimestre.; The applications of agrochemicals are common practices used to protect and nourish crops, including phytosanitary products and fertilizers. The result of a proper application involves achieving the desired effect while minimizing product losses for the protection of human health and the environment. The objective of this study was to characterize the probability of occurrence of optimal meteorological conditions to achieve better application quality. Information recorded by an automatic weather station at Estancia La Morocha (Balcarce, Buenos Aires province) was collected for the years 2006-2018. The results indicated that the probabilities of occurrence of optimal conditions (maximum wind speed: 4 m s-1, maximum air temperature of 30 °C, and minimum relative humidity of 20%) were below 50% in practically all quarters and time slots. From 12 am to 7 am, these probabilities remained between 30% and 50%, with the autumn period being closer to 50%. On the other hand, in the time range from 11 am to 5 pm, optimal application conditions occurred on less than 15% of the days in all quarters, except for the autumn period where it reached 20%. In conclusion, in the southeastern part of Buenos Aires, the meteorological conditions suitable for the application of phytosanitary products and fertilizers generally have a low frequency of occurrence per quarter.

¿Qué desarrollo frente a la crisis civilizatoria? Tensiones creativas para la liberación

CONICET Digital -

¿Qué desarrollo frente a la crisis civilizatoria? Tensiones creativas para la liberación; What Development In The Face Of The Civilizational Crisis? Creative Tensions For Liberation Bilmes, Julián Este trabajo, de índole teórica, aborda la problemática del desarrollo, cuyo debate se reactualizó a raíz de la pandemia y la agudización de la crisis civilizatoria contemporánea, desde la óptica de la liberación y situado desde la periferia latinoamericana. Se postula que desde un punto de vista decolonial se puede abordar este problema en clave de tensiones creativas, y se propone para ello las siguientes: A) desarrollo / posdesarrollo; B) modernidad / transmodernidad; C) Estado / comunidad organizada; D) tiempos y horizontes estructurales / coyunturales. Se postula, pues, la necesidad de atender en el corto y mediano plazo al desafío del desarrollo autónomo y soberano de nuestras naciones, como a los grandes desafíos estructurales, de largo plazo y comunes a toda la humanidad, que refieren tanto al posdesarrollo como a la transmodernidad. Ello demanda articular un fuerte rol de un Estado transformador, “por arriba”, con la potencia del poder popular, “por abajo”, a la vez que conjugar táctica y estrategia, coyuntura y estructura, abrevando en el pensamiento estratégico desde y para Nuestra América. Se finaliza planteando ciertas perspectivas auspiciosas para ello que depara la actual transición histórico-espacial del sistema mundial.; This paper, of a theoretical nature, approaches the problem of development, whose debate has been reactivated as a result of the pandemic and the worsening of the contemporary civilizational crisis, from a liberation perspective and situated from the Latin American periphery. It is postulated that from a decolonial point of view this problem can be approached in the key of creative tensions, and the following are proposed for this purpose: A) development / post-development; B) modernity / transmodernity; C) State / organized community; D) structural / conjunctural times and horizons. It is therefore postulated the need to address in the short and medium term the challenge of the autonomous and sovereign development of our nations, as well as the great structural, long-term challenges common to all humanity, which refer to both post-development and transmodernity. This demands to articulate a strong role of a transforming State, "from above", with the potential of popular power, "from below", while combining tactics and strategy, conjugating conjuncture and structure, drawing on the strategic thinking from and for Our America. It ends by raising certain auspicious perspectives for this that the current historical- spatial transition of the world system has in store.

Vibrational and cohesive properties in 4d and 5d transition metals: systematics and interrelations

CONICET Digital -

Vibrational and cohesive properties in 4d and 5d transition metals: systematics and interrelations Bertoldi, Dalía Surena; Fernandez Guillermet, Armando Jorge Motivated by the striking regularities between experimental quantities related to the vibrational properties of the 4d and 5d series early noted by Fernández Guillermet and Grimvall [Phys. Rev. B, 1989, 40(3), 1521], a systematic theoretical study has been made of the vibrational density of states (VDOS) of Ag, Au, Pd, Pt, Rh, Ir, Ru, Os, Tc, Re, Mo, W, Nb, Ta, Zr and Hf. The frequency moments ωD(j), expressed as Debye temperatures θD(j) for 0 ≤ j ≤ 100 were evaluated. Various remarkable correlations between these quantities are reported, which have their roots in the relations of homology between the VDOS. From the θD(j), several k(j) quantities with dimensions of force constants are calculated. For the elements 4d and 5d transition series, these quantities are shown to be strongly correlated, with independence of the value of j. It is suggested that the various interrelations between the θD(j) and k(j) parameters arrived at in the current work have their roots in the homologous variations of the cohesion forces across the 4d and 5d transition series, as revealed by thermophysical properties such as the bulk modulus and the cohesive energy.

Aerogeles basados en quitosano para la remediación de efluentes textiles

CONICET Digital -

Aerogeles basados en quitosano para la remediación de efluentes textiles; Chitosan based aerogels for textile wastewater remediation Kloster, Melina; Mosiewicki, Mirna Alejandra; Marcovich, Norma Esther Los aerogeles son materiales porosos de muy baja densidad que pueden ser utilizados en diversas aplicaciones de interés tecnológico, entre ellas se destaca la adsorción de contaminantes presentes en medio acuoso. En este trabajo se obtuvieron aerogeles basados en quitosano a partir de la liofilización de hidrogeles entrecruzados con glutaraldehído. Estos materiales fueron caracterizados a partir de su densidad, porosidad, grado de hinchamiento y estabilidad en diferentes solventes y el punto de carga cero. Además, para probar el comportamiento de los materiales como adsorbentes de contaminantes, se realizaron ensayos de cinética de adsorción utilizando el colorante aniónico Rojo Congo. Los datos experimentales de estos ensayos se ajustaron satisfactoriamente mediante el modelo de pseudo-segundo orden. Las propiedades y la capacidad de adsorción de las muestras resultaron dependientes de la composición de las mismas. Se obtuvieron materiales más estables y con mejor desempeño en adsorción al aumentar el contenido de quitosano o de glutaraldehído.; Aerogels are porous materials that have very low density and can be used in various technological applications, among which the adsorption of contaminants from wastewater stands out. In this work, chitosan-based aerogels were obtained from the lyophilization of hydrogels cross-linked with glutaraldehyde. These materials were characterized by measuring their density, porosity, swelling degree and stability in different solvents and point of zero charge. Moreover, to test the behavior of the obtained materials as contaminant adsorbents, kinetic tests were carried out using Congo Red anionic dye. The experimental data from those tests were satisfactorily fitted with pseudo-second order model. It was found that the properties and adsorption capacities of the samples depended on their composition. More stable materials with better adsorption performance were obtained using higher contents of chitosan or glutaraldehyde.

Aerobic denitrification with an electrode as the sole electron and energy source

CONICET Digital -

Aerobic denitrification with an electrode as the sole electron and energy source Rodríguez Simón, Carlos Norberto; Pedetta, Andrea; Busalmen, Juan Pablo; Bonanni, P. Sebastian Biological nitrogen removal from water and wastewater typically requires separate processes for nitrification and denitrification due to different oxygen concentration requirements of these processes. However, in a simpler and more economic approach, denitrification can occur under aerobic conditions if a suitable electron donor is available. While organic compounds have traditionally been used as electron donors for aerobic denitrification, this study explores the application of an electrode as sole electron donor and energy source for denitrifying bacteria in the presence of oxygen. This approach enables simultaneous nitrification and denitrification in a single vessel, even in the absence of organic carbon. Results indicate that nitrate removal rates are higher under aerobic conditions than under anaerobic conditions, owing to a higher respiration rate of the involved bacteria. Electron fluxes analysis reveal that each bacterium reduces nitrate preferentially over oxygen. Notably, the electrochemical potential for aerobic denitrification with an electrode as electron donor is higher than that of anaerobic denitrification, which could increase the power outputs of microbial electrochemical technologies. These findings expand the potential applications of aerobic denitrification and highlight the promising use of electrodes as electron donors for simpler and more efficient nitrogen removal from carbon deficient water and wastewater.

Reflexiones sobre las relaciones entre pasado y futuro en una época de urgencias

CONICET Digital -

Reflexiones sobre las relaciones entre pasado y futuro en una época de urgencias; Reflections on the relations between past and future in times of urgency Belvedresi, Rosa Elena En este trabajo consideraremos algunas de las críticas que ha recibido la tesis del tiempo histórico que lo entiende como un producto de la Modernidad, ligado a la expectativa de un futuro (mejor) que espera por venir. Dos líneas de argumentación nos interesan abordar en este trabajo. La primera, señalar que el supuesto del futuro como el tiempo de la esperanza (en clave política, no religiosa) ha entrado en crisis como consecuencia de la persistencia de formas del pasado que se resisten a pasar. La segunda, subrayar la necesidad de redefinir el tiempo de manera tal que no solo involucre al tiempo social en clave humana, sino que también tenga en cuenta a la especie humana como un factor determinante de lo que sucede en el planeta al resto de los seres vivos. Lo que queremos señalar es, por un lado, que las tesis que cuestionan la idea tradicional del tiempo tienen razón al afirmar que esa idea del tiempo ya no se sostiene, aunque señalaremos algunas diferencias. Por otro lado, queremos marcar la persistencia de ciertas formas del tiempo que se resisten a ser obsoletas y obturan la imaginación de nuevos futuros.; In this paper we will consider some of the criticisms that the thesis of historical time as a product of Modernity has received, linked to the expectation of a (better) future that awaits to come. We are interested in addressing two lines of argument in this paper. The first is to point out that the assumption of the future as the time of hope (in a political key, not a religious one) is in crisis because of the persistence of ways from the past that refuse to go away. The second is to underline the need to redefine time in such a way that it not only involves social time in human tems, but also considers the human species as a determining factor of what happens to the rest of the beings on the planet. What we want to point out is, on the one hand, that the theses that question the traditional idea of time are right in stating that this idea of time is no longer sustained, although we will point out some differences. On the other hand, we want to highlight the persistence of certain forms of time that resist to becoming obsolete and obstruct the imagination of new futures.

Políticas institucionales de las universidades argentinas para acompañar trayectorias en las STEM

CONICET Digital -

Políticas institucionales de las universidades argentinas para acompañar trayectorias en las STEM; Institutional policies of Argentine universities to accompanytrajectories in STEM González, Giselle El artículo describe comparativamente cómo acompañan las universidades las trayectorias en áreas STEM [1]. Parte de una perspectiva internalista que interroga a la organización en el entendido que la puesta en marcha de políticas universitarias no presupone su éxito. Desde un diseño cualitativo se seleccionó a dos universidades públicas de la Argentina y dentro de éstas a las carreras de ingeniería consideradas «estratégicas» para el desarrollo futuro. Los resultados son negativos en términos de implementación y equidad.; It comparatively describes how universities accompany trajectories in STEM areas. It starts from an internalist perspective that questions the organization with the understanding that the implementation of university policies does not presuppose their success. From a qualitative design, two public universities in Argentina were selected and within them the engineering careers considered “strategic” for future development. The results are negative in terms of implementation and equity.

Estimating species distribution changes due to human impacts: the 2020's status of the jaguar in South America

CONICET Digital -

Estimating species distribution changes due to human impacts: the 2020's status of the jaguar in South America Jędrzejewski, Włodzimierz; Morato, Ronaldo G.; Negrões, Nuno; Wallace, Robert B.; Paviolo, Agustin Javier; de Angelo, Carlos Daniel; Thompson, Jeffrey J.; Quiroga, Verónica Andrea; Tobler, Mathias; Ferraz, Katia Maria P.M.B.; Peres Portugal, Marina; Viscarra, María; Ayala Crespo, Guido Marcos; Cruz, María Paula; Esterci Ramalho, Emiliano; Maffei, Leonardo; Robinson, Nathaniel; Breitenmoser, Urs; Breitenmoser, Christine; Polisar, John; Quigley, Howard; Hoogesteijn, Rafael; Gerra, Nelly; Barboza, Kathrin; Cromwel, Lemuel; González Maya, José F.; Johnson, Stacey; Velásquez, Grisel; Vivas, Ilad; Abarca, María Monitoring species distribution over time and understanding factors and mechanisms that determine it is crucial for effective conservation planning. We estimated the current jaguar Panthera onca distribution in South America based on a large set of records (2,557) from 2000–2020 and a set of absence points (both field collected and randomly selected from known jaguar absence areas) using a combination of kriging interpolation and logistic regression models. The current jaguar range in South America is estimated at 7.9 million km2 which is 14% less than the estimate for 2015 and 25% less than for 2000. The reduction of the jaguar’s South American range has been continuous and relatively rapid. Our logistic regression models show that the decrease in jaguar distribution across South America was mainly driven by increasing deforestation, road density, pasture and farmland area, and human population density. During the last 20 years, negative changes in the jaguar habitat suitability (ranging from minor to major) occurred over various parts of the jaguar’s range, including core areas in the Amazon basin, covering 9.3% of the area of the jaguar range. We also show that different ecological factors drive the distribution of jaguar populations in different eco-regions. Based on this work, we propose a stronger international collaboration in monitoring jaguar populations and conservation efforts and a new approach for estimating species distribution for IUCN Red List assessments.

Isoparametric Functions and Solutions of Yamabe Type Equations on Manifolds with Boundary

CONICET Digital -

Isoparametric Functions and Solutions of Yamabe Type Equations on Manifolds with Boundary Henry, Guillermo Sebastian; Zuccotti, Juan Rodrigo Let (M, g) be a compact Riemannian manifold with non-empty boundary. Provided that f is an isoparametric function of (M, g), we prove existence results for positive solutions of the Yamabe equation that are constant along the level sets of f. If (M, g) has positive constant scalar curvature, minimal boundary and admits an isoparametric function we also prove multiplicity results for positive solutions of the Yamabe equation on (M x N, g + th) where (N, h) is any closed Riemannian manifold with positive constant scalar curvature.

Chiral knife edge: A simplified rattleback to illustrate spin inversion

CONICET Digital -

Chiral knife edge: A simplified rattleback to illustrate spin inversion Jagla, Eduardo Alberto; Rojo, Alberto G. We present the chiral knife edge rattleback, an alternative version of previously presented systems that exhibit spin inversion. We offer a full treatment of the model using qualitative arguments, analytical solutions as well as numerical results. We treat a reduced, one–mode problem which not only contains the essence of the physics of spin inversion, but that also exhibits an unexpected connection to the Chaplygin sleigh, providing new insight into the non-holonomic structure of the problem. We also present exact results for the full problem together with estimates of the time between inversions that agree with previous results in the literature.

A multisociety Delphi consensus statement on new fatty liver disease nomenclature

CONICET Digital -

A multisociety Delphi consensus statement on new fatty liver disease nomenclature Rinella, Mary E.; Lazarus, Jeffrey V.; Ratziu, Vlad; Francque, Sven M.; Sanyal, Arun J.; Kanwal, Fasiha; Romero, Diana; Abdelmalek, Manal F.; Anstee, Quentin M.; Arab, Juan Pablo; Arrese, Marco; Bataller, Ramon; Beuers, Ulrich; Boursier, Jerome; Bugianesi, Elisabetta; Byrne, Christopher D.; Castro Narro, Graciela E.; Chowdhury, Abhijit; Cortez Pinto, Helena; Cryer, Donna R.; Cusi, Kenneth; El Kassas, Mohamed; Klein, Samuel; Sookoian, Silvia Cristina; Yilmaz, Yusuf; Younossi, Zobair; Hobbs, Ansley; Villota Rivas, Marcela; Newsome, Philip N. The principal limitations of the terms NAFLD and NASH are the reliance on exclusionary confounder terms and the use of potentially stigmatising language. This study set out to determine if content experts and patient advocates were in favor of a change in nomenclature and/or definition. A modified Delphi process was led by three large pan-national liver associations. The consensus was defined a priori as a supermajority (67%) vote. An independent committee of experts external to the nomenclature process made the final recommendation on the acronym and its diagnostic criteria. A total of 236 panelists from 56 countries participated in 4 online surveys and 2 hybrid meetings. Response rates across the 4 survey rounds were 87%, 83%, 83%, and 78%, respectively. Seventy-four percent of respondents felt that the current nomenclature was sufficiently flawed to consider a name change. The terms “nonalcoholic” and “fatty” were felt to be stigmatising by 61% and 66% of respondents, respectively. Steatotic liver disease was chosen as an overarching term to encompass the various aetiologies of steatosis. The term steatohepatitis was felt to be an important pathophysiological concept that should be retained. The name chosen to replace NAFLD was metabolic dysfunction–associated steatotic liver disease. There was consensus to change the definition to include the presence of at least 1 of 5 cardiometabolic risk factors. Those with no metabolic parameters and no known cause were deemed to have cryptogenic steatotic liver disease. A new category, outside pure metabolic dysfunction–associated steatotic liver disease, termed metabolic and alcohol related/associated liver disease (MetALD), was selected to describe those with metabolic dysfunction–associated steatotic liver disease, who consume greater amounts of alcohol per week (140–350 g/wk and 210–420 g/wk for females and males, respectively). The new nomenclature and diagnostic criteria are widely supported and nonstigmatising, and can improve awareness and patient identification.

Recent disturbance events recorded in the sedimentary infill of Lago Guillelmo (Argentina): tephra falls and hydrogeomorphic processes

CONICET Digital -

Recent disturbance events recorded in the sedimentary infill of Lago Guillelmo (Argentina): tephra falls and hydrogeomorphic processes Amat, Pablo; Villarosa, Gustavo; Beigt, Debora; Outes, Ana Valeria; Cottet, Julieta; Domínguez, Lucía Inés; Cottescu Szeraws, Alexander Nicolas Christian; Barbosa Hetherington, Andrés We studied two natural disturbances that affect the Parque Nacional NahuelHuapi area: tephra fall events from Andean volcanoes and hydrogeomorphicprocesses within catchments related to heavy rains. We carried out a surfaceanalysis, describing the main morphometric features of the selected watershed,informally called La Cantera watershed; analyzing satellite images and historicalaerial photographs; looking for evidence of processes related to these disturbanceevents in the watershed and morphological changes in the alluvial fan generatedover the delta. The subaqueous environment was analyzed through bathymetries,sediment cores, and Ground Penetrating Radar (GPR) profiles, taken in the distaldeltaic environment of the watershed. In the sedimentary record of the lake, weidentified 12 tephra layers deposited in the last 200 years, attributed to CordónCaulle, Calbuco, and Osorno volcanoes. These were chronologically correlatedwith previously documented eruptions of these volcanic centers, using vitroclastmorphology, mineral association, and stratigraphic position. We also identified10 epiclastic layers corresponding to sediments with terrigenous componentsand terrestrial organic matter, interpreted as hyperpycnites. We assign twohyperpycnite deposits to a debris flow that occurred in the area in February 2015that caused several damages and roadblocks, based on the stratigraphic positionof these deposits in the cores, and the identification of sediments associated withthis event on the lake surface in satellite images. After the correlation betweenthe GPR radargram units with the lacustrine cores, we associated one major radarunit with a (1) tephra layer and (2) lobe-shaped morphologies, interpreted asa hyperpycnite deposits, located in front of the outflow of an abandoned rivercourse. The results allow inferring a significant anthropic impact in the lacustrinerecord, as a result of the construction of Route 40 and gravel mining activitiesafter 1969 that affected the distal drainage network of the La Cantera watershed,generating topographic lows that make it difficult for subaerial flows to reachthe lake. This work shows the importance of the integration between subaerialprocesses that occur throughout a basin with the underwater processes that takeplace in the deltaic environment, to understand the extension and characteristicsof these natural disturbances.

Synthesis and Processing of Near Infrared—Activated Vitrimer Nanocomposite Films Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon Nanotubes

CONICET Digital -

Synthesis and Processing of Near Infrared—Activated Vitrimer Nanocomposite Films Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon Nanotubes Byrne Prudente, Tomas Eduardo; Mauro, Diandra; Puig, Julieta; Altuna, Facundo Ignacio; Da Ros, Tatiana; Hoppe, Cristina Elena Films of a vitrimer based on the reaction between diglycidylether of bisphenol A and glutaric acid in the presence of 1-methylimidazole were processed using a solvent-based technique. The curing schedule was divided into two steps: first, a soluble linear polymer was formed through the reaction of the diacid and the diepoxide, and then the crosslinking was induced at a higher temperature via transesterification reactions. This epoxy–acid vitrimer was modified with multi-walled carbon nanotubes (MWCNTs) functionalized with β-hydroxyesters, produced by a robust and straightforward strategy based on a two-phase reaction between oxidized MWCNTs and phenylglycidylether. Nanocomposite vitrimer films were obtained by drop casting a dispersion of the functionalized MWCNTs in the linear polymer/cyclohexanone solution, followed by a thermal treatment. A high degree of dispersion of the carbon nanostructures was attained thanks to the β-hydroxyester functionalization when compared with oxidized MWCNTs. Nanocomposite films showed a significant photothermal effect (reaching 200 ◦C or above in 30 s) upon NIR light irradiation (850 nm) from a single LED (500 mW/cm2 ). The released heat was used to activate the shape memory effect and weld and heal the vitrimer matrix, proving the success of this easy strategy for the generation of remotely activated carbon-based vitrimer nanocomposites.

Páginas

Suscribirse a Facultad de Ciencias Químicas de la Universidad Nacional de Córdoba agregador - Ciencia y Tecnología