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

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

Penggunaan Alat Peraga Polydron Frameworks pada Materi Geometri untuk Meningkatkan Kemampuan Spasial Matematis Siswa SMP Kelas VIII

Tujuandaripenelitianiniadalahuntukmengetahui peningkatan kemampuan spasial matematis siswa yang memperoleh pembelajaran menggunakan alat peraga Polydron Frameworks dengan siswa yang memperoleh pembelajaran konvensional. Penelitianini adalah penelitian kuasi eksperimen dengan bentuk non-equivalent control group dengan sampel penelitiansiswa kelas VIII pada salah satu SMP di Tangerang. Hasil penelitianinimenunjukkanbahwapeningkatan kemampuan spasial matematis pada kelompok siswa yang menggunakan alat peraga Polydron Frameworks lebih baik dari pada kelompok siswa yang belajar menggunakan pembelajaran konvensional

Environmental consequences of oil production from oil sands

Crude oil from oil sands will constitute a substantial share of future global oil demand. Oil sands deposits account for a third of globally proven oil reserves, underlie large natural forested areas, and have extraction methods requiring large volumes of freshwater. Yet little work has been done to quantify some of the main environmental impacts of oil sands operations. Here we examine forest loss and water use for the world's major oil sands deposits. We calculate actual and potential rates of water use and forest loss both in Canadian deposits, where oil sands extraction is already taking place, and in other major deposits worldwide. We estimated that their exploitation, given projected production trends, could result in 1.31 km3 yr−1 of freshwater demand and 8700 km2 of forest loss. The expected escalation in oil sands extraction thus portends extensive environmental impacts

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

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