8,300 research outputs found

    The complex networks of earth minerals and chemical elements

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    We study the large-scale organization of the mineral-mineral (MMN) and element-element (EEN) complex networks by analyzing their topological structures. We see that the MMN and EEN are homogeneous, display large cliquishness, small average path length and large average degrees. Most of these networks display uniform degree distribution with the exception of the weighted EEN, which display a power-law degree distribution with exponential tail. All these topological characteristics appear to be consequence of the evolutionary mechanisms giving place to the minerals on Earth mantle, which as a whole display a relatively uniform major element composition. We also study the correlations between some topological network parameters and the abundance of chemical elements in different scenarios. Good correlation is obtained between the weighted degree and the abundance of elements in Earth's crustal rocks

    How the parts organize in the whole : a top-downview of molecular descriptors and properties for QSARand drug design

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    Sometimes the complexity of a system, or the properties derived from it, do depend neither on the individual characteristics of the components of the system nor on the nature of the physical forces that hold them together. In such cases the properties derived from the 'organization' of the system given by the connectivity of its elements can be determinant for explaining the structure of such systems. Here we explore the necessity of accounting for these structural characteristics in the molecular descriptors. We show that graph theory is the most appropriate mathematical theory to account for such molecular features. We review a method (TOPS-MODE) that is able to transform simple molecular descriptors, such as logP, polar surface area, molar refraction, charges, etc., into series of descriptors that account for the distribution of these characteristics (hydrophobicity, polarity, steric effects, etc) across the molecule. We explain the mathematical and physical principles of the TOPS-MODE method and develop three examples covering the description and interpretation of skin sensitisation of chemicals, chromosome aberration produced by organic molecules and drug binding to human serum albumin

    Palabras de fiesta : en la boda de Pepita Pallares Moreno y Jose Luis Estrada Segalerva

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    Ex libris de Jose Luis Estrada.Copia Digital : Diputación de Málaga. Biblioteca Cánovas del Castillo, 201

    Religious education in Mexico

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    https://place.asburyseminary.edu/ecommonsatsdissertations/2390/thumbnail.jp

    Religious education in Mexico

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    https://place.asburyseminary.edu/ecommonsatsdissertations/2390/thumbnail.jp

    Spatiotemporal Dynamics of Global Drought

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    Understanding the evolution and physical drivers of drought is critical to informing forecasting efforts. One aspect that has seldom been explored is the joint evolution of droughts in space and time. Most studies fix the reference area and focus on their temporal variability, or study their spatial heterogeneity over fixed durations. This work implements a Lagrangian approach by aggregating contiguous areas under drought into clusters. These clusters become the frame of reference and are tracked as they evolve through space and time. Clusters were identified from soil moisture data from the Climate Forecast System Reanalysis (1979-2009). Evapotranspiration, moisture fluxes, and precipitation were used to explore the relevance of possible mechanisms of drought propagation. While most droughts remain near their origin, the centroid of 10% of clusters traveled at least 1,400-3,100 km, depending on the continent. This approach also revealed that large-scale droughts often lock into further growth and intensification
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