Noticias en español
El uso de imágenes satelitales en Argentina y sus aplicaciones en espacios urbanos
En el seminario se hará un recorrido por el uso de imágenes satelitales para el análisis de procesos urbanos en Argentina, particularmente en ciudades intermedias bonaerenses. Se presentarán estudios de casos aplicados y metodológicos sobre: la extracción de firmas espectrales para el estudio de densidades urbanas, comparación de productos Landsat y Sentinel 2, efectos de la pandemia en concentraciones de NO2, análisis de procesos de urbanización y consecuencias en el ambiente, y la utilización de productos mixtos para el análisis de patrones climáticos....
Read MoreLong time asymptotics for critical birth and death diffusion processes.
Resumen: We study the long time behavior for the distribution of a critical birth and death diffusion process, motivated by population dynamics in changing environment (cf. a recent paper by Calvez, Henry, Méléard, Tran). The birth rates are bounded but death rates are unbounded. Our analysis is based on the spectral properties of the associated Feynman Kac semigroup. We require a standard spectral gap property for this semigroup with a dominant eigenfunction vanishing at infinity. Some examples of diffusions, diffusions with jump, pure jump dynamics are given for which it is true....
Read MoreTwo-Edge Connectivity via Pac-Man Gluing.
Abstract: We study the 2-edge-connected spanning subgraph (2-ECSS) problem: Given a graph G, compute a connected subgraph H of G with the minimum number of edges such that H is spanning, i.e., V(H) = V(G), and H is 2-edge-connected, i.e., H remains connected upon the deletion of any single edge, if such an H exists. The 2-ECSS problem is known to be NP-hard. In this work, we provide a polynomial-time (5/4 + epsilon)-approximation for the problem for an arbitrarily small epsilon>0, improving the previous best approximation ratio of 13/10 + epsilon. Our improvement is based on two main...
Read MoreParabolic trapped subvarieties in globally hyperbolic spacetimes.
Abstract: Abstract: Since 1965 when Penrose defined the concept of a trapped surface (compact and without boundary) in a 4-dimensional space-time, these surfaces have been an important object of study for geometricians and theoretical physicists, standing out for their mathematical properties as well as for their applications in general relativity. Trapped surfaces can be defined in terms of the causal character of their mean curvature vector, which allows us to generalize them to subvarieties, not necessarily compact and of any dimension and/or codimension, in space-time. In this...
Read MoreThe k-Yamabe flow and its solitons.
Abstract: The Yamabe problem is a classical question in conformal geometry that seeks for existence of metrics with constant scalar curvature within a conformal class. The problem was posed by H. Yamabe in 1960 as a possible extension of the famous uniformization theorem, which states that every simply connected Riemann surface is conformally equivalent to the open unit disk, the complex plane or the Riemann sphere. After the conjecture was already confirmed by the work of R. Schoen, an alternative approach was proposed by R.Hamilton in 1989. He suggested to use a geometric flow, which is...
Read MoreAQS2GEE: aplicación para la cartografía de áreas quemadas mediante Sentinel-2 y Google Earth Engine.
Resumen AQS2GEE es una herramienta innovadora desarrollada en Google Earth Engine para detectar y clasificar áreas quemadas utilizando imágenes Sentinel-2 de manera rápida y eficiente. Gracias a su procesamiento en la nube y el uso de índices espectrales como el NBR y ΔNBR, permite analizar el impacto de los incendios forestales sin necesidad de software especializado. Su fácil acceso y capacidad para generar mapas y estadísticas en pocos clics la convierten en una solución ideal para investigadores, gestores ambientales y tomadores de decisiones que buscan mejorar el monitoreo y la...
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