http://sedici.unlp.edu.ar:80/handle/10915/86775 2026-10-10T02:11:50Z 2026-10-10T02:11:50Z Mesón, Alejandro Mario Vericat, Fernando http://sedici.unlp.edu.ar:80/handle/10915/198459 2026-09-09T20:25:04Z 2009-02-23T00:00:00Z

Articulo Far East Journal of Dynamical Systems; vol. 11, no. 1 In this article we obtain bounds for large deviations processes in dynamical systems, in which non-additive sequences are considered. More specifically, for sequences [equation] and dynamical maps [equation] such that [equation] converges uniformly we estimate the growing rate of [equation] where n is a finite Borel measure on X and I is a real interval. We consider also a particular case in which the process description easily follows from Ellis theorem.

2009-02-23T00:00:00Z In this article we obtain bounds for large deviations processes in dynamical systems, in which non-additive sequences are considered. More specifically, for sequences [equation] and dynamical maps [equation] such that [equation] converges uniformly we estimate the growing rate of [equation] where n is a finite Borel measure on X and I is a real interval. We consider also a particular case in which the process description easily follows from Ellis theorem. Borges, Augusto Miranda-Rodrı́guez, Jerónimo R. Ceccarelli, Alberto Sebastián Ventura, Guilherme Sedzinski, Jakub López-Schier, Hernán Chara, Osvaldo http://sedici.unlp.edu.ar:80/handle/10915/197038 2026-07-17T20:25:44Z 2025-01-01T00:00:00Z

Articulo iScience; vol. 28, no. 11 During tissue development and regeneration, cells interpret and exert mechanical forces that are challenging to measure in vivo. Stress inference algorithms have thus emerged as powerful tools to estimate tissue stresses. Yet, effectively incorporating tissue dynamics into these algorithms remains elusive. Here, we introduce ForSys, a Python-based software that infers intercellular stresses and intracellular pressures from time- lapse microscopy. After validation, we applied ForSys to the migrating zebrafish lateral-line primordium, revealing increased stress during the cell rounding that precedes mitosis and accurately predicting the onset of epithelial rosettogenesis. We further used ForSys to study neuromast development and uncovered mechanical asymmetries linked to cell type-specific adhesion. The software performs both static and dynamic stress inference, supports command-line use, scripting, and a user-friendly graphical interface within Fiji, and accepts segmentation inputs from EPySeg and Cellpose. This versatility of ForSys enables the analysis of spatiotemporal patterns of mechanical forces during tissue morphogenesis in vivo.

2025-01-01T00:00:00Z During tissue development and regeneration, cells interpret and exert mechanical forces that are challenging to measure in vivo. Stress inference algorithms have thus emerged as powerful tools to estimate tissue stresses. Yet, effectively incorporating tissue dynamics into these algorithms remains elusive. Here, we introduce ForSys, a Python-based software that infers intercellular stresses and intracellular pressures from time- lapse microscopy. After validation, we applied ForSys to the migrating zebrafish lateral-line primordium, revealing increased stress during the cell rounding that precedes mitosis and accurately predicting the onset of epithelial rosettogenesis. We further used ForSys to study neuromast development and uncovered mechanical asymmetries linked to cell type-specific adhesion. The software performs both static and dynamic stress inference, supports command-line use, scripting, and a user-friendly graphical interface within Fiji, and accepts segmentation inputs from EPySeg and Cellpose. This versatility of ForSys enables the analysis of spatiotemporal patterns of mechanical forces during tissue morphogenesis in vivo. Lavalle, Natalia Guillermina Miranda-Rodríguez, Jerónimo Cura Costa, Emanuel Borges, Augusto Viader-Llargués, Oriol López-Schier, Hernán Chara, Osvaldo http://sedici.unlp.edu.ar:80/handle/10915/196330 2026-06-29T20:24:54Z 2026-05-01T00:00:00Z

Articulo Journal of Theoretical Biology; vol. 623 Biological systems are never in equilibrium, yet they maintain stability in the face of continuous external disturbances. A prime example of this is organ regeneration, during which organs are reliably rebuilt through controlled cellular proliferation. In this study, we employ a cell-based computational modelling approach to investigate the proliferative response of an organ after injury. We developed a minimal two-dimensional Cellular Potts Model (CPM) using empirical data from regenerating neuromasts in larval zebrafish. Remarkably, the CPM both qualitatively and quantitatively recapitulates the regenerative response of neuromasts following laser-mediated cell ablation. Assuming that cell proliferation is locally regulated by a delayed switch, we discovered that mitotic activity ceases once the type-dependent number of neighbouring cells exceeds a deterministic critical threshold. An intriguing corollary of our findings is that a local negative feedback loop among identical cells may represent a general mechanism underlying organ-level proportional homeostasis.

2026-05-01T00:00:00Z Biological systems are never in equilibrium, yet they maintain stability in the face of continuous external disturbances. A prime example of this is organ regeneration, during which organs are reliably rebuilt through controlled cellular proliferation. In this study, we employ a cell-based computational modelling approach to investigate the proliferative response of an organ after injury. We developed a minimal two-dimensional Cellular Potts Model (CPM) using empirical data from regenerating neuromasts in larval zebrafish. Remarkably, the CPM both qualitatively and quantitatively recapitulates the regenerative response of neuromasts following laser-mediated cell ablation. Assuming that cell proliferation is locally regulated by a delayed switch, we discovered that mitotic activity ceases once the type-dependent number of neighbouring cells exceeds a deterministic critical threshold. An intriguing corollary of our findings is that a local negative feedback loop among identical cells may represent a general mechanism underlying organ-level proportional homeostasis. Rossatto, R. G. Álvarez, Hugo Ariel Carlevaro, Carlos Manuel Bordin, José Rafael http://sedici.unlp.edu.ar:80/handle/10915/196219 2026-06-25T20:27:14Z 2026-06-01T00:00:00Z

Articulo Physica A: Statistical Mechanics and its Applications; vol. 692 We investigate a minimal chase-and-escape model on a two-dimensional square lattice with randomly distributed static obstacles, focusing on how geometric disorder controls collective pursuit dynamics. Chasers and escapers move according to short-range sensing rules, while the density of obstacles tunes the connectivity of the accessible space. Using a combination of geometric analysis, dynamical observables, survival statistics, and transport characterization, we establish a direct link between lattice connectivity and pursuit efficiency. A Breadth-First Search analysis reveals that obstacle-induced fragmentation leads to a progressive loss of accessibility before the percolation threshold, defining the effective initial conditions for the dynamics. The trapping time and capture cost exhibit a non-monotonic dependence on obstacle density, reflecting a competition between path elongation in connected environments and geometric confinement near the percolation threshold. Survival analysis shows that the decay of the escaper population follows a Weibull form, with characteristic time and shape parameters displaying clear crossovers as a function of obstacle density, signaling the coexistence of cooperative capture and confinement-dominated trapping. Transport properties, quantified through the mean-squared displacement exponent, further support this picture, revealing sub- diffusive dynamics and a convergence toward a geometry-controlled regime near percolation. Overall, our results demonstrate that chase-and-escape dynamics in disordered environments are governed by a geometry-driven crossover, where percolation and connectivity act as unifying control parameters for spatial, temporal, and collective behavior.

2026-06-01T00:00:00Z We investigate a minimal chase-and-escape model on a two-dimensional square lattice with randomly distributed static obstacles, focusing on how geometric disorder controls collective pursuit dynamics. Chasers and escapers move according to short-range sensing rules, while the density of obstacles tunes the connectivity of the accessible space. Using a combination of geometric analysis, dynamical observables, survival statistics, and transport characterization, we establish a direct link between lattice connectivity and pursuit efficiency. A Breadth-First Search analysis reveals that obstacle-induced fragmentation leads to a progressive loss of accessibility before the percolation threshold, defining the effective initial conditions for the dynamics. The trapping time and capture cost exhibit a non-monotonic dependence on obstacle density, reflecting a competition between path elongation in connected environments and geometric confinement near the percolation threshold. Survival analysis shows that the decay of the escaper population follows a Weibull form, with characteristic time and shape parameters displaying clear crossovers as a function of obstacle density, signaling the coexistence of cooperative capture and confinement-dominated trapping. Transport properties, quantified through the mean-squared displacement exponent, further support this picture, revealing sub- diffusive dynamics and a convergence toward a geometry-controlled regime near percolation. Overall, our results demonstrate that chase-and-escape dynamics in disordered environments are governed by a geometry-driven crossover, where percolation and connectivity act as unifying control parameters for spatial, temporal, and collective behavior. Basiuk, Lucas Camino–Willhuber, Gastón Bendersky, Mariana Meyra, Ariel Germán Irastorza, Ramiro Miguel Carlevaro, Carlos Manuel http://sedici.unlp.edu.ar:80/handle/10915/194182 2026-05-08T20:21:18Z 2025-01-01T00:00:00Z

Articulo Simplified model of a spinal functional unit to determinesurgical parameters XLI Congreso Argentino de Mecánica Computacional (Buenos Aires, 11 al 14 de noviembre de 2025); Mecánica Computacional; vol. 42, no. 19 Se presenta un modelo computacional simplificado de la unidad funcional espinal L4-L5 para explorar parámetros relevantes en cirugías mínimamente invasivas como la discoplastía percutánea ósea. Usando software libre (Gmsh, Dolfinx, Paraview), se pueden personalizar variaciones en la altura del disco y el volumen de cemento óseo. Los resultados incluyen verificación con un caso clínico, esti- mación del volumen inyectado y análisis de tensiones pre y postoperatorias. El trabajo busca aportar a la optimización de parámetros quirúrgicos.; A simplified computational model of the L4-L5 functional spinal unit is presented to explore relevant parameters in minimally invasive surgeries such as percutaneous cement discoplasty. Using open-source software (Gmsh, Dolfinx, Paraview), variations in disc height and bone cement volume can be customized. The results include verification with a clinical case, estimation of injected cement volume, and analysis of pre- and postoperative stresses. This work aims to contribute to the optimization of surgical parameters.

2025-01-01T00:00:00Z Se presenta un modelo computacional simplificado de la unidad funcional espinal L4-L5 para explorar parámetros relevantes en cirugías mínimamente invasivas como la discoplastía percutánea ósea. Usando software libre (Gmsh, Dolfinx, Paraview), se pueden personalizar variaciones en la altura del disco y el volumen de cemento óseo. Los resultados incluyen verificación con un caso clínico, esti- mación del volumen inyectado y análisis de tensiones pre y postoperatorias. El trabajo busca aportar a la optimización de parámetros quirúrgicos. A simplified computational model of the L4-L5 functional spinal unit is presented to explore relevant parameters in minimally invasive surgeries such as percutaneous cement discoplasty. Using open-source software (Gmsh, Dolfinx, Paraview), variations in disc height and bone cement volume can be customized. The results include verification with a clinical case, estimation of injected cement volume, and analysis of pre- and postoperative stresses. This work aims to contribute to the optimization of surgical parameters. Mateyca, Andrea Celeste Mougabure Cueto, Gastón Sanmartino, Mariana http://sedici.unlp.edu.ar:80/handle/10915/188423 2025-12-06T04:22:36Z 2023-01-01T00:00:00Z

Objeto de conferencia XVI Congreso Nacional de Estudios del Trabajo (Buenos Aires, 2 al 4 de agosto de 2023) En esta ponencia abordaremos un tema poco tratado y sumamente importante: las condiciones y medio de ambiente de trabajo de los técnicos de campo (TC) de los programas de Chagas de Argentina. Los1 TC se encargan de la evaluación entomológica (búsqueda de vinchucas) y el rociado con insecticidas en viviendas que se encuentran en zonas con riesgo de transmisión vectorial del T. cruzi. Esta ponencia es producto de una tesis doctoral2 más amplia que estudió los saberes, prácticas educativas y formación de los TC. En particular, en este texto desarrollaremos una incipiente problematización de las condiciones y medio ambiente de su trabajo y de los factores de riesgo psicosociales a los que se encuentran expuestos. Para ello, en primer lugar realizaremos una revisión de antecedentes en el tema, y presentaremos una breve reconstrucción teórica de algunos marcos utilizados para el análisis. Luego, mostraremos la metodología utilizada para la construcción y análisis de los datos. Finalmente, presentaremos los resultados del estudio, y cerramos con algunas reflexiones finales.

2023-01-01T00:00:00Z En esta ponencia abordaremos un tema poco tratado y sumamente importante: las condiciones y medio de ambiente de trabajo de los técnicos de campo (TC) de los programas de Chagas de Argentina. Los1 TC se encargan de la evaluación entomológica (búsqueda de vinchucas) y el rociado con insecticidas en viviendas que se encuentran en zonas con riesgo de transmisión vectorial del T. cruzi. Esta ponencia es producto de una tesis doctoral2 más amplia que estudió los saberes, prácticas educativas y formación de los TC. En particular, en este texto desarrollaremos una incipiente problematización de las condiciones y medio ambiente de su trabajo y de los factores de riesgo psicosociales a los que se encuentran expuestos. Para ello, en primer lugar realizaremos una revisión de antecedentes en el tema, y presentaremos una breve reconstrucción teórica de algunos marcos utilizados para el análisis. Luego, mostraremos la metodología utilizada para la construcción y análisis de los datos. Finalmente, presentaremos los resultados del estudio, y cerramos con algunas reflexiones finales. Mateyca, Andrea Celeste http://sedici.unlp.edu.ar:80/handle/10915/187415 2025-11-18T20:32:37Z 2022-01-01T00:00:00Z

Objeto de conferencia VII Jornadas Nacionales, V Jornadas Latinoamericanas de Investigadores/as en Formación en Educación. Instituto de Investigaciones en Ciencias de la Educación (IICE) (UBA, 23 al 25 de noviembre de 2022) En este trabajo presentamos algunas líneas de lo que se convertirá en uno de los capítulos de la tesis de doctorado en Ciencias de la Educación (UNLP) titulada "Aportes a la comprensión integral de la problemática de Chagas: saberes y prácticas educativas de los técnicos de campo”. En esta investigación nos interesamos por un eslabón clave de las políticas públicas destinadas a la prevención del Chagas: los técnicos de los programas operativos. Ellos -varones cis- trabajan en programas operativos en todo el país evaluando la presencia de vinchucas (insectos que transmiten el parásito que causa el Chagas) en las viviendas y rociando con insecticidas cuando es necesario. Además, enseñan diversas cuestiones sobre el Chagas a las personas con las que interactúan y colaboran con la gestión de los programas operativos y la investigación en la temática. Entendemos que para realizar estas acciones utilizan saberes que construyen en su propia experiencia laboral. La pregunta que nos hicimos fue ¿cuáles son estos saberes y cómo se construyen? En esta ponencia caracterizamos y reflexionamos acerca de dichos saberes. En cuanto a los aspectos metodológicos, realizamos un estudio cualitativo e interpretativo que incluyó entrevistas a técnicos de campo de tres programas operativos del país (Chaco, San Juan y Córdoba) y otros actores (personal de gestión y administrativo de programas de Chagas e investigadorxs) y observación participante a uno de los programas con los que se trabajó (San Juan). Los técnicos de campo construyen, transmiten y utilizan un conjunto de saberes del trabajo que les permiten realizar sus actividades: acceder a las viviendas, realizar la evaluación entomológica, la desinsectación y enseñar distintos aspectos sobre Chagas a la población. Finalmente, entendemos que estos saberes surgen de aprendizajes sociales durante la práctica laboral en los distintos territorios y a partir de la enseñanza de un técnico más experimentado a uno novato.

2022-01-01T00:00:00Z En este trabajo presentamos algunas líneas de lo que se convertirá en uno de los capítulos de la tesis de doctorado en Ciencias de la Educación (UNLP) titulada "Aportes a la comprensión integral de la problemática de Chagas: saberes y prácticas educativas de los técnicos de campo”. En esta investigación nos interesamos por un eslabón clave de las políticas públicas destinadas a la prevención del Chagas: los técnicos de los programas operativos. Ellos -varones cis- trabajan en programas operativos en todo el país evaluando la presencia de vinchucas (insectos que transmiten el parásito que causa el Chagas) en las viviendas y rociando con insecticidas cuando es necesario. Además, enseñan diversas cuestiones sobre el Chagas a las personas con las que interactúan y colaboran con la gestión de los programas operativos y la investigación en la temática. Entendemos que para realizar estas acciones utilizan saberes que construyen en su propia experiencia laboral. La pregunta que nos hicimos fue ¿cuáles son estos saberes y cómo se construyen? En esta ponencia caracterizamos y reflexionamos acerca de dichos saberes. En cuanto a los aspectos metodológicos, realizamos un estudio cualitativo e interpretativo que incluyó entrevistas a técnicos de campo de tres programas operativos del país (Chaco, San Juan y Córdoba) y otros actores (personal de gestión y administrativo de programas de Chagas e investigadorxs) y observación participante a uno de los programas con los que se trabajó (San Juan). Los técnicos de campo construyen, transmiten y utilizan un conjunto de saberes del trabajo que les permiten realizar sus actividades: acceder a las viviendas, realizar la evaluación entomológica, la desinsectación y enseñar distintos aspectos sobre Chagas a la población. Finalmente, entendemos que estos saberes surgen de aprendizajes sociales durante la práctica laboral en los distintos territorios y a partir de la enseñanza de un técnico más experimentado a uno novato. Ithuralde, Raúl Esteban Becerro, Verónica Cordero, Silvina http://sedici.unlp.edu.ar:80/handle/10915/187229 2025-11-12T20:18:20Z 2022-01-01T00:00:00Z

Objeto de conferencia I Jornadas Nacionales de Investigación y Formación Docente en Argentina (CABA, 30 de junio y 1 de julio de 2022) En este trabajo presentamos un primer análisis de una experiencia de formación docente continua en el campo de la Educación en Ciencias Naturales, Ambiental y en Salud (CNAS), orientada a maestrxs del Nivel Primario que como Grupo de Didáctica las Ciencias1 diseñamos e implementamos durante 2021 desde el Instituto Nacional de Formación Docente. Dicha experiencia formó parte de una política educativa nacional de formación y acompañamiento del trabajo docente en pandemia, orientada a que docentes en servicio pudieran apropiarse de nuevas herramientas y reflexionar sobre sus prácticas, y así fomentar su transformación. Constituyó, por tanto, una instancia de puesta en acto de la política educativa nacional (Ball et al, 2012), puesta en acto en la que emerge la autonomía del trabajo vivo en acto (Franco y Merhy, 2016) de lxs trabajadorxs de la educación, quienes en este proceso pueden resignificar las políticas en un sentido emancipador (y de cuidado) o de disciplinamiento.

2022-01-01T00:00:00Z En este trabajo presentamos un primer análisis de una experiencia de formación docente continua en el campo de la Educación en Ciencias Naturales, Ambiental y en Salud (CNAS), orientada a maestrxs del Nivel Primario que como Grupo de Didáctica las Ciencias1 diseñamos e implementamos durante 2021 desde el Instituto Nacional de Formación Docente. Dicha experiencia formó parte de una política educativa nacional de formación y acompañamiento del trabajo docente en pandemia, orientada a que docentes en servicio pudieran apropiarse de nuevas herramientas y reflexionar sobre sus prácticas, y así fomentar su transformación. Constituyó, por tanto, una instancia de puesta en acto de la política educativa nacional (Ball et al, 2012), puesta en acto en la que emerge la autonomía del trabajo vivo en acto (Franco y Merhy, 2016) de lxs trabajadorxs de la educación, quienes en este proceso pueden resignificar las políticas en un sentido emancipador (y de cuidado) o de disciplinamiento. Ithuralde, Raúl Esteban Cordero, Silvina http://sedici.unlp.edu.ar:80/handle/10915/178701 2025-05-07T04:11:16Z 2024-01-01T00:00:00Z

Objeto de conferencia V Coloquio de Investigación Educativa en Argentina (Rosario, 7, 8 y 9 de agosto de 2024) Este trabajo constituye un primer avance de la investigación titulada “Por la reinvención del mundo: Posibilidades y desafíos de la Educación Ambiental crítica en la producción curricular”, desarrollada por el Grupo de Didáctica de las Ciencias (IFLYSIB, CONICET-UNLP/UNSE/UBA/UNLu). Se parte de considerar que, tanto en su hacer en los territorios, como en su construcción académica, la Educación Ambiental (EA) está conformada por una gran diversidad de enfoques y perspectivas relacionados con los contextos de su práctica y producción, de diferentes posicionamientos políticos y filosóficos sobre la educación, de diversos alcances y conceptualizaciones sobre las nociones de ambiente y de sustentabilidad y de distintos modelos de desarrollo (o alternativas al mismo) que desde esas posiciones se promueven. En los últimos años se han producido numerosas sistematizaciones sobre la EA (Sauvé, 2004 y 2010; Corbetta y Sessano, 2015), en particular sobre la “ambientalización” curricular (por ejemplo Gonzalez Gaudiano, 2012) y sobre su implementación en la Educación Superior (Corbetta, 2019; Eschenhagen, 2016).

2024-01-01T00:00:00Z Este trabajo constituye un primer avance de la investigación titulada “Por la reinvención del mundo: Posibilidades y desafíos de la Educación Ambiental crítica en la producción curricular”, desarrollada por el Grupo de Didáctica de las Ciencias (IFLYSIB, CONICET-UNLP/UNSE/UBA/UNLu). Se parte de considerar que, tanto en su hacer en los territorios, como en su construcción académica, la Educación Ambiental (EA) está conformada por una gran diversidad de enfoques y perspectivas relacionados con los contextos de su práctica y producción, de diferentes posicionamientos políticos y filosóficos sobre la educación, de diversos alcances y conceptualizaciones sobre las nociones de ambiente y de sustentabilidad y de distintos modelos de desarrollo (o alternativas al mismo) que desde esas posiciones se promueven. En los últimos años se han producido numerosas sistematizaciones sobre la EA (Sauvé, 2004 y 2010; Corbetta y Sessano, 2015), en particular sobre la “ambientalización” curricular (por ejemplo Gonzalez Gaudiano, 2012) y sobre su implementación en la Educación Superior (Corbetta, 2019; Eschenhagen, 2016). Ithuralde, Raúl Esteban http://sedici.unlp.edu.ar:80/handle/10915/178637 2025-04-30T20:11:55Z 2024-01-01T00:00:00Z

Objeto de conferencia V Coloquio de Investigación Educativa en Argentina (Rosario, 7, 8 y 9 de agosto de 2024) Este trabajo constituye un avance de la tesis de Doctorado en Humanidades (Área Educación) – Universidad Nacional de Tucumán, titulada: “Instituciones educativas de nivel primario de la modalidad de personas jóvenes y adultas: diversidades socioculturales y la enseñanza de las Ciencias Naturales, el Ambiente y la Salud”. La provincia de Santiago del Estero tiene uno de los índices más altos de analfabetismo a nivel país. El 20% de la población santiagueña mayor de 15 años, lo que representa a 119.113 personas, carecía de terminalidad primaria en 2010, duplicando la media nacional. En el ciclo 2014, cursaron la Educación Primaria de Jóvenes y Adultes (EPJA) 5217 sujetos, de los cuales egresaron 1048. Esto muestra una baja demanda efectiva (Llosa et al, 2001) para esta modalidad, en comparación a la alta demanda potencial relevada y un alto desgranamiento.

2024-01-01T00:00:00Z Este trabajo constituye un avance de la tesis de Doctorado en Humanidades (Área Educación) – Universidad Nacional de Tucumán, titulada: “Instituciones educativas de nivel primario de la modalidad de personas jóvenes y adultas: diversidades socioculturales y la enseñanza de las Ciencias Naturales, el Ambiente y la Salud”. La provincia de Santiago del Estero tiene uno de los índices más altos de analfabetismo a nivel país. El 20% de la población santiagueña mayor de 15 años, lo que representa a 119.113 personas, carecía de terminalidad primaria en 2010, duplicando la media nacional. En el ciclo 2014, cursaron la Educación Primaria de Jóvenes y Adultes (EPJA) 5217 sujetos, de los cuales egresaron 1048. Esto muestra una baja demanda efectiva (Llosa et al, 2001) para esta modalidad, en comparación a la alta demanda potencial relevada y un alto desgranamiento. De Virgiliis, Andrés Meyra, Ariel Germán Ciach, Alina http://sedici.unlp.edu.ar:80/handle/10915/167561 2024-06-27T20:29:55Z 2024-01-01T00:00:00Z

Articulo Molecules; vol. 29, no. 7 A monolayer consisting of two types of particles, with energetically favored alternating stripes of the two components, is studied by Monte Carlo simulations and within a mesoscopic theory. We consider a triangular lattice model and assume short-range attraction and long-range repulsion between particles of the same kind, as well as short-range repulsion and long-range attraction for the cross-interaction. The structural evolution of the model upon increasing temperature is studied for equal chemical potentials of the two species. We determine the structure factor, the chemical potential– density isotherms, the specific heat, and the compressibility, and show how these thermodynamic functions are associated with the spontaneous formation of stripes with varying degrees of order.

2024-01-01T00:00:00Z A monolayer consisting of two types of particles, with energetically favored alternating stripes of the two components, is studied by Monte Carlo simulations and within a mesoscopic theory. We consider a triangular lattice model and assume short-range attraction and long-range repulsion between particles of the same kind, as well as short-range repulsion and long-range attraction for the cross-interaction. The structural evolution of the model upon increasing temperature is studied for equal chemical potentials of the two species. We determine the structure factor, the chemical potential– density isotherms, the specific heat, and the compressibility, and show how these thermodynamic functions are associated with the spontaneous formation of stripes with varying degrees of order. Montangie, Lisandro Montani, Fernando Fabián http://sedici.unlp.edu.ar:80/handle/10915/160308 2023-11-17T20:06:46Z 2017-01-01T00:00:00Z

Articulo Physica A; vol. 471 Recent neurophysiological experiments suggest that populations of neurons use a computational scheme in which spike timing is regulated by common non-Gaussian inputs across neurons. The presence of beyond-pairwise correlations in the neuronal inputs and the spiking outputs following a non-Gaussian statistics elicits the need of developing a new theoretical framework taking into account the complexity of synchronous activity patterns. To this end, we quantify the amount of higher-order correlations in the common neuronal inputs and outputs of a population of neurons. We provide a novel formalism, of easy numerical implementation, that can capture the subtle changes of the inputs heterogeneities. Within our approach, correlations across neurons arise from -Gaussian inputs into threshold neurons and higher-order correlations in the spiking outputs activity are quantified by the parameter . We present an exhaustive analysis of how input statistics are transformed in this threshold process into output statistics, and we show under which conditions higher-order correlations can lead to either bigger or smaller number of synchronized spikes in the neural population outputs.

2017-01-01T00:00:00Z Recent neurophysiological experiments suggest that populations of neurons use a computational scheme in which spike timing is regulated by common non-Gaussian inputs across neurons. The presence of beyond-pairwise correlations in the neuronal inputs and the spiking outputs following a non-Gaussian statistics elicits the need of developing a new theoretical framework taking into account the complexity of synchronous activity patterns. To this end, we quantify the amount of higher-order correlations in the common neuronal inputs and outputs of a population of neurons. We provide a novel formalism, of easy numerical implementation, that can capture the subtle changes of the inputs heterogeneities. Within our approach, correlations across neurons arise from -Gaussian inputs into threshold neurons and higher-order correlations in the spiking outputs activity are quantified by the parameter . We present an exhaustive analysis of how input statistics are transformed in this threshold process into output statistics, and we show under which conditions higher-order correlations can lead to either bigger or smaller number of synchronized spikes in the neural population outputs. Baravalle, Francisco Rosso, Osvaldo Aníbal Montani, Fernando Fabián http://sedici.unlp.edu.ar:80/handle/10915/160307 2023-11-17T20:06:47Z 2018-01-01T00:00:00Z

Articulo Physica A; vol. 511 Electroencephalograms reflect the electrical activity of the brain, which can be considered ruled by a chaotic nonlinear dynamics. We consider human electroencephalogram recordings during different motor type activities, and when imagining that they perform this activity. We characterize the different dynamics of the cortex according to distinct motor and imagined movement tasks using an information theory approach and a wavelet decomposition. More specifically, we use the entropy-complexity plane H × C in combination with the wavelet decomposition to precisely quantify the dynamics of the neuronal activity showing that the current theoretical framework allows us to distinguish realized and imagined tasks within the cortex.

2018-01-01T00:00:00Z Electroencephalograms reflect the electrical activity of the brain, which can be considered ruled by a chaotic nonlinear dynamics. We consider human electroencephalogram recordings during different motor type activities, and when imagining that they perform this activity. We characterize the different dynamics of the cortex according to distinct motor and imagined movement tasks using an information theory approach and a wavelet decomposition. More specifically, we use the entropy-complexity plane H × C in combination with the wavelet decomposition to precisely quantify the dynamics of the neuronal activity showing that the current theoretical framework allows us to distinguish realized and imagined tasks within the cortex. Montangie, Lisandro Montani, Fernando Fabián http://sedici.unlp.edu.ar:80/handle/10915/160305 2023-11-17T20:06:48Z 2016-01-01T00:00:00Z

Articulo Physical Review E; vol. 94, no. 4 Spike correlations among neurons are widely encountered in the brain. Although models accounting for pairwise interactions have proved able to capture some of the most important features of population activity at the level of the retina, the evidence shows that pairwise neuronal correlation analysis does not resolve cooperative population dynamics by itself. By means of a series expansion for short time scales of the mutual information conveyed by a population of neurons, the information transmission can be broken down into firing rate and correlational components. In a proposed extension of this framework, we investigate the information components considering both second- and higher-order correlations.We showthat the existence of a mixed stimulus-dependent correlation term defines a new scenario for the interplay between pairwise and higher-than-pairwise interactions in noise and signal correlations that would lead either to redundancy or synergy in the information-theoretic sense.

2016-01-01T00:00:00Z Spike correlations among neurons are widely encountered in the brain. Although models accounting for pairwise interactions have proved able to capture some of the most important features of population activity at the level of the retina, the evidence shows that pairwise neuronal correlation analysis does not resolve cooperative population dynamics by itself. By means of a series expansion for short time scales of the mutual information conveyed by a population of neurons, the information transmission can be broken down into firing rate and correlational components. In a proposed extension of this framework, we investigate the information components considering both second- and higher-order correlations.We showthat the existence of a mixed stimulus-dependent correlation term defines a new scenario for the interplay between pairwise and higher-than-pairwise interactions in noise and signal correlations that would lead either to redundancy or synergy in the information-theoretic sense. Montangie, Lisandro Montani, Fernando Fabián http://sedici.unlp.edu.ar:80/handle/10915/160303 2023-11-17T20:06:49Z 2015-01-01T00:00:00Z

Articulo Physica A; vol. 421 Recent experiments involving a relatively large population of neurons have shown a very significant amount of higher-order correlations. However, little is known of how these affect the integration and firing behavior of a population of neurons beyond the second order statistics. To investigate how higher-order inputs statistics can shape beyond pairwise spike correlations and affect information coding in the brain, we consider a neuronal pool where each neuron fires stochastically. We develop a simple mathematically tractable model that makes it feasible to account for higher-order spike correlations in a neuronal pool with highly interconnected common inputs beyond second order statistics. In our model, correlations between neurons appear from q-Gaussian inputs into threshold neurons. The approach constitutes the natural extension of the Dichotomized Gaussian model, where the inputs to the model are just Gaussian distributed and therefore have no input interactions beyond second order. We obtain an exact analytical expression for the joint distribution of firing, quantifying the degree of higher-order spike correlations, truly emphasizing the functional aspects of higher-order statistics, as we account for beyond second order inputs correlations seen by each neuron within the pool. We determine how higherorder correlations depend on the interaction structure of the input, showing that the joint distribution of firing is skewed as the parameter q increases inducing larger excursions of synchronized spikes. We show how input nonlinearities can shape higher-order correlations and enhance coding performance by neural populations.

2015-01-01T00:00:00Z Recent experiments involving a relatively large population of neurons have shown a very significant amount of higher-order correlations. However, little is known of how these affect the integration and firing behavior of a population of neurons beyond the second order statistics. To investigate how higher-order inputs statistics can shape beyond pairwise spike correlations and affect information coding in the brain, we consider a neuronal pool where each neuron fires stochastically. We develop a simple mathematically tractable model that makes it feasible to account for higher-order spike correlations in a neuronal pool with highly interconnected common inputs beyond second order statistics. In our model, correlations between neurons appear from q-Gaussian inputs into threshold neurons. The approach constitutes the natural extension of the Dichotomized Gaussian model, where the inputs to the model are just Gaussian distributed and therefore have no input interactions beyond second order. We obtain an exact analytical expression for the joint distribution of firing, quantifying the degree of higher-order spike correlations, truly emphasizing the functional aspects of higher-order statistics, as we account for beyond second order inputs correlations seen by each neuron within the pool. We determine how higherorder correlations depend on the interaction structure of the input, showing that the joint distribution of firing is skewed as the parameter q increases inducing larger excursions of synchronized spikes. We show how input nonlinearities can shape higher-order correlations and enhance coding performance by neural populations. Montani, Fernando Oliynyk, Andriy Fadiga, Luciano http://sedici.unlp.edu.ar:80/handle/10915/160299 2023-11-17T20:06:51Z 2017-01-01T00:00:00Z

Articulo International Journal of Neural Systems; vol. 27, no. 02 Whether premotor/motor neurons encode information in terms of spiking frequency or by their relative time of firing, which may display synchronization, is still undetermined. To address this issue, we used an information theory approach to analyze neuronal responses recorded in the premotor (area F5) and primary motor (area F1) cortices of macaque monkeys under four different conditions of visual feedback during hand grasping. To evaluate the sensitivity of spike timing correlation between single neurons, we investigated the stimulus dependent synchronization in our population of pairs. We first investigated the degree of correlation of trial-to-trial fluctuations in response strength between neighboring neurons for each condition, and second estimated the stimulus dependent synchronization by means of an information theoretical approach. We compared the information conveyed by pairs of simultaneously recorded neurons with the sum of information provided by the respective individual cells. The information transmission across pairs of cells in the primary motor cortex seems largely independent, whereas information transmission across pairs of premotor neurons is summed superlinearly. The brain could take advantage of both the accuracy provided by the independency of F1 and the synergy allowed by the superlinear information population coding in F5, distinguishing thus the generalizing role of F5

2017-01-01T00:00:00Z Whether premotor/motor neurons encode information in terms of spiking frequency or by their relative time of firing, which may display synchronization, is still undetermined. To address this issue, we used an information theory approach to analyze neuronal responses recorded in the premotor (area F5) and primary motor (area F1) cortices of macaque monkeys under four different conditions of visual feedback during hand grasping. To evaluate the sensitivity of spike timing correlation between single neurons, we investigated the stimulus dependent synchronization in our population of pairs. We first investigated the degree of correlation of trial-to-trial fluctuations in response strength between neighboring neurons for each condition, and second estimated the stimulus dependent synchronization by means of an information theoretical approach. We compared the information conveyed by pairs of simultaneously recorded neurons with the sum of information provided by the respective individual cells. The information transmission across pairs of cells in the primary motor cortex seems largely independent, whereas information transmission across pairs of premotor neurons is summed superlinearly. The brain could take advantage of both the accuracy provided by the independency of F1 and the synergy allowed by the superlinear information population coding in F5, distinguishing thus the generalizing role of F5 Iribarren, Luciano Guerrero Tamayo, Katherine Ithuralde, Raúl Esteban Dumrauf, Ana Gabriela Cordero, Silvina http://sedici.unlp.edu.ar:80/handle/10915/159926 2023-11-08T20:07:47Z 2023-08-22T00:00:00Z

Articulo Environmental Education and curricular designs for Basic Secondary Education in the province of Buenos Aires: critical analysis in the context of the new national legislation; Educação ambiental e projetos curriculares para a educação secundária básica na província de Buenos Aires: análise crítica no contexto da nova legislação nacional Praxis Educativa; vol. 27, no. 3 Las formas de inclusión de la Educación Ambiental (EA) en el currículum son una preocupación de larga data en el campo didáctico latinoamericano. Aquí analizamos los diseños curriculares para la Escuela Secundaria Básica de la provincia de Buenos Aires, Argentina. Si bien en normativas jerárquicamente superiores (Ley de Educación Provincial y Marco General de Política Curricular) la EA se fundamenta desde perspectivas críticas y etnográficas, es dispar su presencia transversal en los diseños curriculares. En algunas materias encontramos un curriculum vacío de EA mientras que otras presentan perspectivas fragmentarias y contradictorias entre sí. Sólo en Ciencias Sociales, Geografía y Construcción de Ciudadanía se plantea una visión crítica y etnográfica, que presenta vínculos con conflictos ambientales contemporáneos. En Geografía recuperamos la dimensión vivencial y el disfrute de lo ambiental, un aporte a las pedagogías del conflicto ambiental y a la hora de implementar la nueva normativa nacional de EA.; The forms in which Environmental Education (EE) is included in the curriculum are a long-standing concern in the Latin American didactic field. In this paper we analyse the current curricular designs for the Basic Secondary School in the province of Buenos Aires, Argentina. Although in hierarchically superior regulations (Provincial Education Law and General Framework of Curricular Policy), EE is based on critical and ethnographic perspectives, it has an uneven transversal presence in the curricular designs. Some subjects present an empty EE curriculum, while others show fragmentary and contradictory perspectives. Only in Social Sciences, Geography and Citizenship Building is there a critical and ethnographic vision, linked to contemporary environmental conflicts. From Geography we recovered the experiential dimension and the enjoyment of the environment as a contribution to the pedagogies of environmental conflict and to the ongoing implementation the new national EE regulations.; As formas de inclusão da Educação Ambiental (EA) no currículo são uma preocupação de longa data no campo didático latino-americano. Aqui analisamos os projetos curriculares em vigor para o Ensino Secundário Básico na província de Buenos Aires, Argentina. Embora nas regulações hierarquicamente superiores (Lei Provincial de Educação e Marco Geral da Política Curricular) a EA baseia-se em perspectivas críticas e etnográficas, sua presença transversal nos projetos curriculares é heterogênea. Algumas disciplinas apresentam um currículo de EA vazio, enquanto outras mostram perspectivas fragmentadas e contraditórias. Apenas em Ciências Sociais, Geografia e Construção da Cidadania existe uma visão crítica e etnográfica, ligada aos conflitos ambientais contemporâneos. Na Geografia, recuperamos a dimensão experiencial e a fruição do meio ambiente como uma contribuição para as pedagogias do conflito ambiental e para a implementação das novas regulações nacionais de EA.

2023-08-22T00:00:00Z Las formas de inclusión de la Educación Ambiental (EA) en el currículum son una preocupación de larga data en el campo didáctico latinoamericano. Aquí analizamos los diseños curriculares para la Escuela Secundaria Básica de la provincia de Buenos Aires, Argentina. Si bien en normativas jerárquicamente superiores (Ley de Educación Provincial y Marco General de Política Curricular) la EA se fundamenta desde perspectivas críticas y etnográficas, es dispar su presencia transversal en los diseños curriculares. En algunas materias encontramos un curriculum vacío de EA mientras que otras presentan perspectivas fragmentarias y contradictorias entre sí. Sólo en Ciencias Sociales, Geografía y Construcción de Ciudadanía se plantea una visión crítica y etnográfica, que presenta vínculos con conflictos ambientales contemporáneos. En Geografía recuperamos la dimensión vivencial y el disfrute de lo ambiental, un aporte a las pedagogías del conflicto ambiental y a la hora de implementar la nueva normativa nacional de EA. The forms in which Environmental Education (EE) is included in the curriculum are a long-standing concern in the Latin American didactic field. In this paper we analyse the current curricular designs for the Basic Secondary School in the province of Buenos Aires, Argentina. Although in hierarchically superior regulations (Provincial Education Law and General Framework of Curricular Policy), EE is based on critical and ethnographic perspectives, it has an uneven transversal presence in the curricular designs. Some subjects present an empty EE curriculum, while others show fragmentary and contradictory perspectives. Only in Social Sciences, Geography and Citizenship Building is there a critical and ethnographic vision, linked to contemporary environmental conflicts. From Geography we recovered the experiential dimension and the enjoyment of the environment as a contribution to the pedagogies of environmental conflict and to the ongoing implementation the new national EE regulations. As formas de inclusão da Educação Ambiental (EA) no currículo são uma preocupação de longa data no campo didático latino-americano. Aqui analisamos os projetos curriculares em vigor para o Ensino Secundário Básico na província de Buenos Aires, Argentina. Embora nas regulações hierarquicamente superiores (Lei Provincial de Educação e Marco Geral da Política Curricular) a EA baseia-se em perspectivas críticas e etnográficas, sua presença transversal nos projetos curriculares é heterogênea. Algumas disciplinas apresentam um currículo de EA vazio, enquanto outras mostram perspectivas fragmentadas e contraditórias. Apenas em Ciências Sociais, Geografia e Construção da Cidadania existe uma visão crítica e etnográfica, ligada aos conflitos ambientais contemporâneos. Na Geografia, recuperamos a dimensão experiencial e a fruição do meio ambiente como uma contribuição para as pedagogias do conflito ambiental e para a implementação das novas regulações nacionais de EA. Gago, Paula Alejandra Madrid, Marcos Andrés Boettcher, Stefan Blumenfeld, Raphael King, Peter http://sedici.unlp.edu.ar:80/handle/10915/159864 2023-11-07T20:07:24Z 2023-01-01T00:00:00Z

Articulo Powder Technology; vol. 428 We investigate the effect of a bevelled (or slanted) outlet on the discharge rate of mono-sized spheres from a quasi-two-dimensional silo, using the discrete element method. In contrast to hopper discharges, where the bevelling is across the entire base of the container, we study a bevelled opening that is significantly smaller than the silo width and in which the slanting is limited to half a sphere diameter at the boundary of the outlet. We show that the bevelling increases the flow rate comparably to the inclination in hopper walls. Using Beverloo’s model, we relate this increase in rate to what we define as the ‘effective opening’ of the silo and analyse the velocity profiles associated with the discharges. We show that different openings, having effectively the same discharge rates, give rise to distinctly different internal dynamics in the silo. These results have the potential to aid industrial processes by fine-tuning and improving control of silo discharges, with a minimal impact on silo design, thus significantly reducing production and handling costs.

2023-01-01T00:00:00Z We investigate the effect of a bevelled (or slanted) outlet on the discharge rate of mono-sized spheres from a quasi-two-dimensional silo, using the discrete element method. In contrast to hopper discharges, where the bevelling is across the entire base of the container, we study a bevelled opening that is significantly smaller than the silo width and in which the slanting is limited to half a sphere diameter at the boundary of the outlet. We show that the bevelling increases the flow rate comparably to the inclination in hopper walls. Using Beverloo’s model, we relate this increase in rate to what we define as the ‘effective opening’ of the silo and analyse the velocity profiles associated with the discharges. We show that different openings, having effectively the same discharge rates, give rise to distinctly different internal dynamics in the silo. These results have the potential to aid industrial processes by fine-tuning and improving control of silo discharges, with a minimal impact on silo design, thus significantly reducing production and handling costs. Cavagna, Andrea Fort, Hugo Grigera, Tomás Sebastián http://sedici.unlp.edu.ar:80/handle/10915/159775 2023-11-03T20:07:00Z 2023-01-01T00:00:00Z

Articulo Ecological Indicators; vol. 146 We analyse population dynamics in Barro Colorado Island (Panama) using census data of a 50 ha forest plot spanning 35 years, and address the question whether this community is in a stationary state. Individual species abundances show large fluctuations, but assessing stationariety requires discriminating random fluctuations from actual trends. This requires evaluating mean quantities as well as the structure (i.e. the correlations) of the fluctuations around this mean. We argue that a species average is the best surrogate for the theoretically required but unfeasible history average. We define the overlap, a species-averaged measure of composition similarity, which reveals that the BCI population dynamics is stationary but not static, displaying fluctuations with a characteristic time of around 15 years, two orders of magnitude less than previously estimated.

2023-01-01T00:00:00Z We analyse population dynamics in Barro Colorado Island (Panama) using census data of a 50 ha forest plot spanning 35 years, and address the question whether this community is in a stationary state. Individual species abundances show large fluctuations, but assessing stationariety requires discriminating random fluctuations from actual trends. This requires evaluating mean quantities as well as the structure (i.e. the correlations) of the fluctuations around this mean. We argue that a species average is the best surrogate for the theoretically required but unfeasible history average. We define the overlap, a species-averaged measure of composition similarity, which reveals that the BCI population dynamics is stationary but not static, displaying fluctuations with a characteristic time of around 15 years, two orders of magnitude less than previously estimated. Fort, Hugo Grigera, Tomás Sebastián http://sedici.unlp.edu.ar:80/handle/10915/159774 2023-11-03T20:07:01Z 2021-01-01T00:00:00Z

Articulo Ecological Indicators; vol. 125 The vulnerability of species richness to several factors like, climate change, habitat fragmentation, resource exploitation, etc., poses a challenge to conservation biologists and agencies working to sustain the ecosystem services. Hence, there is a clear need for early warning indicators of species loss generated from empirical data. The tree community of the long-term 50-hectare plot on Barro Colorado Island (BCI), Panama, is one of the most intensively studied in the world. This plot was established in 1981 and fully censused in 1982 then every 5 years from 1985 through 2015. This extensive dataset reveals that some tree species suffered steep population declines. Here we propose an early warning indicator of such tree population crashes and test it against the BCI dataset. The spatial covariance matrices, Cij, of the 20 most abundant tree species in BCI allow us to compute, via MaxEnt, the effective interaction matrices, Jij, among these species for the eight censuses available from 1982 to 2015. For each species i and each census c, the absolute value of the intraspecific competition coefficients Jii(c) are much larger than those of the interspecific interaction coefficients Jij(c) with i ∕= j. We show that this result can be derived from a similar empirical relationship observed for the matrices Cii(c). Our main finding is that for those tree species that suffered steep population declines (of at least 50%), across the eight tree censuses, the drop of Jii is always steeper and occurs before the drop of the corresponding species abundance Ni. Indeed, such sharp declines in Jii occur between 5 and 15 years in advance than comparable declines for Ni, and thus they serve as early warnings of impending population busts. Furthermore, this drop of Jii is linked to the anomalous variance, which is a known early warning of incoming catastrophic shifts.

2021-01-01T00:00:00Z The vulnerability of species richness to several factors like, climate change, habitat fragmentation, resource exploitation, etc., poses a challenge to conservation biologists and agencies working to sustain the ecosystem services. Hence, there is a clear need for early warning indicators of species loss generated from empirical data. The tree community of the long-term 50-hectare plot on Barro Colorado Island (BCI), Panama, is one of the most intensively studied in the world. This plot was established in 1981 and fully censused in 1982 then every 5 years from 1985 through 2015. This extensive dataset reveals that some tree species suffered steep population declines. Here we propose an early warning indicator of such tree population crashes and test it against the BCI dataset. The spatial covariance matrices, Cij, of the 20 most abundant tree species in BCI allow us to compute, via MaxEnt, the effective interaction matrices, Jij, among these species for the eight censuses available from 1982 to 2015. For each species i and each census c, the absolute value of the intraspecific competition coefficients Jii(c) are much larger than those of the interspecific interaction coefficients Jij(c) with i ∕= j. We show that this result can be derived from a similar empirical relationship observed for the matrices Cii(c). Our main finding is that for those tree species that suffered steep population declines (of at least 50%), across the eight tree censuses, the drop of Jii is always steeper and occurs before the drop of the corresponding species abundance Ni. Indeed, such sharp declines in Jii occur between 5 and 15 years in advance than comparable declines for Ni, and thus they serve as early warnings of impending population busts. Furthermore, this drop of Jii is linked to the anomalous variance, which is a known early warning of incoming catastrophic shifts.