Global Quantum Discord in Multipartite Systems

We propose a global measure for quantum correlations in multipartite systems, which is obtained by suitably recasting the quantum discord in terms of relative entropy and local von Neumann measurements. The measure is symmetric with respect to subsystem exchange and is shown to be non-negative for an arbitrary state. As an illustration, we consider tripartite correlations in the Werner-GHZ state and multipartite correlations at quantum criticality. In particular, in contrast with the pairwise quantum discord, we show that the global quantum discord is able to characterize the infinite-order quantum phase transition in the Ashkin-Teller spin chain.Comment: v3: 7 pages, 6 figures. Published versio

Modeling post-fire water erosion mitigation strategies

Abstract. Severe wildfires are often followed by significant increase in runoff and erosion, due to vegetation damage and changes in physical and chemical soil properties. Peak flows and sediment yields can increase up to two orders of magnitude, becoming dangerous for human lives and the ecosystem, especially in the wildland–urban interface. Watershed post-fire rehabilitation measures are usually used to mitigate the effects of fire on runoff and erosion, by protecting soil from splash and shear stress detachment and enhancing its infiltration capacity. Modeling post-fire erosion and erosion mitigation strategies can be useful in selecting the effectiveness of a rehabilitation method. In this paper a distributed model based on the Revised Universal Soil Loss Equation (RUSLE), properly parameterized for a Mediterranean basin located in Sardinia, is used to determine soil losses for six different scenarios describing both natural and post-fire basin condition, the last also accounting for the single and combined effect of different erosion mitigation measures. Fire effect on vegetation and soil properties have been mimed by changing soil drainage capacity and organic matter content, and RUSLE factors related to soil cover and protection measures. Model results, validated using measured data on erosion rates from the literature and in situ field campaigns, show the effect of the analyzed rehabilitation treatments in reducing the amount of soil losses with the peculiar characteristics of the spatial distribution of such changes. In particular, the mulching treatment substantially decreases erosion both in its mean value (−75%) and in the spatially distribution of the erosion levels over the burned area . On the contrary, the breaking up of the hydrophobic layer decreases post-fire mean soil losses of about the 14%, although it strongly influences the spatial distribution of the erosion levels

A new dataset of global irrigation areas from 2001 to 2015

About 40% of global crop production takes place on irrigated land, which accounts for approximately 20% of the global farmland. The great majority of freshwater consumption by human societies is associated with irrigation, which contributes to a major modification of the global water cycle by enhancing evapotranspiration and reducing surface and groundwater runoff. In many regions of the world irrigation contributes to streamflow and groundwater depletion, soil salinization, cooler microclimate conditions, and altered land-atmosphere interactions. Despite the important role played by irrigation in food security, water cycle, soil productivity, and near-surface atmospheric conditions, its global extent remains poorly quantified. To date global maps of irrigated land are often based on estimates from circa year 2000. Here we apply artificial intelligence methods based on machine learning algorithms to satellite remote sensing and monthly climate data to map the spatial extent of irrigated areas between 2001 and 2015. We provide global annual maps of irrigated land at ≈9km resolution for the 2001-2015 and we make this dataset available online

Monogamy of Quantum Discord by Multipartite Correlations

We introduce a monogamy inequality for quantum correlations, which implies that the sum of pairwise quantum correlations is upper limited by the amount of multipartite quantum correlations as measured by the global quantum discord. This monogamy bound holds either for pure or mixed quantum states provided that bipartite quantum discord does not increase under discard of subsystems. We illustrate the monogamy behavior for multipartite pure states with Schmidt decomposition as well as for W-GHZ mixed states. As a by-product, we apply the monogamy bound to investigate residual multipartite correlations.Comment: 5 pages, 2 figures. v2: published versio

Extensión universitaria : Difusión y enseñanza de ciencias de la salud en escuelas

Acercar conocimientos y avances científicos a los sectores sociales, particularmente a los más postergados, es de importancia fundamental para su desarrollo. Con este objetivo, incentivado por la UNESCO, y en cumplimiento de funciones de extensión universitaria, estamos desarrollando la serie "De la Universidad a la Escuela", que comprende actividades docentes innovadoras en el área de las Ciencias Naturales. En esta presentación se resume una experiencia de difusión y enseñanza de ciencias relacionadas con la salud en una escuela primaria cuyos alumnos pertenecen a familias de bajos recursos. Dado que los niños, bajo el asesoramiento del INTA, utilizaban cáscaras de naranja en la huerta orgánica, se decidió comunicar hallazgos científicos de la UBA relacionados con la actividad antifúngica de las mismas. Se incorporaron extractos de naranja como potenciales agentes conservadores en un jabón de potasio elaborado ad hoc en la experiencia didáctica. Además, los alumnos y docentes descubrieron la actividad terapéutica de los extractos sobre plantas de la huerta infectadas por hongos. Algunas de estas actividades innovadoras han sido propuestas para su incorporación al PROCAM y propiciarían la higiene, el cuidado de la salud y la realización de micro-emprendimientos por parte de las familias de los alumnos, para su beneficio.Trabajos del área Ciencias NaturalesDepartamento de Ciencias Exactas y Naturale

Aplicación de conocimientos generados en impartidos por la universidad en el desarrollo de actividades docentes innovadoras: infecciones infantiles

Las funciones universitarias incluyen docencia, investigación y extensión. Integrando ellas, decidimos difundir conocimientos científicos impartidos y generados por la UBA a alumnos de 4º grado de una escuela primaria porteña. De esta forma, surgió esta experiencia innovadora perteneciente a la serie "De la Universidad a la Escuela". Objetivos: Estimular el interés de los niños por el cuidado de la salud, la Medicina y disciplinas afines. Propiciar la apertura a la investigación científica. Contenidos: Microorganismos comunes en infecciones infantiles, su identificación microscópica, toma de muestras y cultivo en medios apropiados. Normas de cuidado de la salud y conocimientos acerca de la existencia e investigación de distintos productos antimicrobianos en relación con el tratamiento y prevención de infecciones. Desarrollo: Se realizaron clases teóricas y prácticas en el laboratorio de la escuela. Se seleccionó un conjunto de técnicas, enfoques y procedimientos usados habitualmente por investigadores y profesionales de la salud. Se reprodujeron los pasos técnicos fundamentales que condujeron al equipo al que pertenece la investigadora al hallazgo de actividad antimicrobiana en plantas autóctonas argentinas. Para todo esto, se realizó una adecuación al nivel educativo de los destinatarios. Aportes: La experiencia extiende socialmente la labor universitaria, promueve el contacto fluido entre distintos niveles educativos, enriquece la curricula de enseñanza primaria en relación con disciplinas afines a la Medicina y educa para la salud, en consonancia con las recomendaciones de la OMS.Sección Naturales.Departamento de Ciencias Exactas y Naturale

Quantum Correlations in Multipartite Quantum Systems

We review some concepts and properties of quantum correlations, in particular multipartite measures, geometric measures and monogamy relations. We also discuss the relation between classical and total correlationsComment: to be published as a chapter of the book "Lectures on general quantum correlations and their applications" edited by F. Fanchini, D. Soares-Pinto, and G. Adesso (Springer, 2017

Transnational agricultural land acquisitions threaten biodiversity in the Global South

Agricultural large-scale land acquisitions have been linked with enhanced deforestation and land use change. Yet the extent to which transnational agricultural large-scale land acquisitions (TALSLAs) contribute to—or merely correlate with—deforestation, and the expected biodiversity impacts of the intended land use changes across ecosystems, remains unclear. We examine 178 georeferenced TALSLA locations in 40 countries to address this gap. While forest cover within TALSLAs decreased by 17% between 2000 and 2018 and became more fragmented, the spatio-temporal patterns of deforestation varied substantially across regions. While deforestation rates within initially forested TALSLAs were 1.5 (Asia) to 2 times (Africa) higher than immediately surrounding areas, we detected no such difference in Europe and Latin America. Our findings suggest that, whereas TALSLAs may have accelerated forest loss in Asia, a different mechanism might emerge in Africa where TALSLAs target areas already experiencing elevated deforestation. Regarding biodiversity (here focused on vertebrate species), we find that nearly all (91%) studied deals will likely experience substantial losses in relative species richness (−14.1% on average within each deal)—with mixed outcomes for relative abundance—due to the intended land use transitions. We also find that 39% of TALSLAs fall at least partially within biodiversity hotspots, placing these areas at heightened risk of biodiversity loss. Taken together, these findings suggest distinct regional differences in the nature of the association between TALSLAs and forest loss and provide new evidence of TALSLAs as an emerging threat to biodiversity in the Globa