666 research outputs found

    Querying Spatio-temporal Patterns in Mobile Phone-Call Databases

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    Abstract — Call Detail Record (CDR) databases contain millions of records with information about cell phone calls, including the position of the user when the call was made/received. This huge amount of spatiotemporal data opens the door for the study of human trajectories on a large scale without the bias that other sources (like GPS or WLAN networks) introduce in the population studied. Also, it provides a platform for the development of a wide variety of studies ranging from the spread of diseases to planning of public transport. Nevertheless, previous work on spatiotemporal queries does not provide a framework flexible enough for expressing the complexity of human trajectories. In this paper we present the Spatiotemporal Pattern System (STPS) to query spatiotemporal patterns in very large CDR databases. STPS defines a regular-expression query language that is intuitive and that allows for any combination of spatial and temporal predicates with constraints, including the use of variables. The design of the language took into consideration the layout of the areas being covered by the cellular towers, as well as “areas ” that label places of interested (e.g. neighborhoods, parks, etc) and topological operators. STPS includes an underlying indexing structure and algorithms for query processing using different evaluation strategies. A full implementation of the STPS is currently running with real, very large CDR databases on Telefónica Research Labs. An extensive performance evaluation of the STPS shows that it can efficiently find complex mobility patterns in large CDR databases. I

    Materias primas de la Luna para emprender la colonización espacial

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    1 página.-- Reportaje.Peer reviewe

    Assessment on proximate composition, dietary fiber, phytic acid and protein hydrolysis of germinated Ecuatorian brown rice

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    Germinated brown rice (GBR) is considered healthier than brown rice (BR) but its nutritive value has been hardly studied. Since nutritive quality of GBR depends on genetic diversity and germination conditions, six Ecuadorian BR varieties were germinated at 28 and 34 ºC for 48 and 96 h in darkness and proximate composition, dietary fiber fractions, phytic acid content as well as degree of protein hydrolysis and peptide content were studied. Protein, lipids, ash and available carbohydrate ranged 7.3-10.4%, 2.0-4.0%, 0.8-1.5% and 71.6 to 84.0%, respectively, in GBR seedlings. Total dietary fiber increased during germination (6.1-13.6%), with a large proportion of insoluble fraction, and phytic acid was reduced noticeably. In general, protein hydrolysis occurred during germination was more accused at 28 ºC for 48 h. These results suggest that GBR can be consumed directly as nutritive staple food for a large population worldwide contributing to their nutritional requirements.This work was partly funded by AGL2010-16310 Project from the Ministry of Economy and Competitiveness (MINECO, Spain).Peer Reviewe

    Maximising the phytochemical content and antioxidant activity of Ecuadorian brown rice sprouts through optimal germination conditions

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    Germinated brown rice (GBR) is considered a healthy alternative to white rice in the fight against chronic diseases. As the functional quality of GBR depends on genotype and germination conditions, the objectives were to identify suitable Ecuadorian brown rice cultivars and optimal germination time and temperature to maximise γ-aminobutyric acid (GABA), total phenolics compounds (TPC) and antioxidant activity of GBR. Regression models for the prediction of phytochemical composition and antioxidant activity in GBR were also obtained. Germination improved GABA, TPC and antioxidant activity in all cultivars. Maximum GABA and antioxidant activity were attained at 34 C for 96 h, while the highest TPC was found at 28 C for 96 h in all cultivars. GBR cv. GO displayed the highest antioxidant activity and cv. 15 was the most effective at accumulating GABA and TPC in the optimal germination conditions. Therefore, Ecuadorian GBR could be used for the preparation of functional foods serving as preventative strategies in combating chronic diseases. © 2013 Elsevier Ltd. All rights reserved.This work was financially supported by AGL2010-16310 Project from the Ministry of Science and Innovation (MICINN, Spain).Peer Reviewe

    Progress in the influence of recycled construction and demolition mineral-based blends on the physical–mechanical behaviour of ternary cementitious matrices

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    [Abstract:] The serious technical and environmental problems associated with the management of construction and demolition wastes (CDW) have led to a worldwide growing interest in the recycling of that waste stream as secondary raw material for sustainable building applications. This research work investigates the physical and mechanical behaviour of mortars made with ternary cements containing 7% of a binary recycled CDW mixture comprising the fine fraction (<5 mm) of recycled concrete waste (both siliceous and calcareous nature) in combination with recycled laminar glass in three different proportions (1/1, 1/2, and 2/1, respectively). To this end, the chemical composition and fineness of the anhydrous ternary cements were analysed, as well as their behaviour in paste and mortar matrices, in both fresh and hardened states, verifying the requirements established by the applicable standards. The results attest to the viability of using these ternary cements, as their performance is comparable to that of an ordinary Portland cement (OPC), without evidencing any significant dependence on the glass content. The compressive strength values decrease by 7–8% with respect to that of the OPC mortar, revealing the prevalence of the filler effect over the pozzolanic reaction. The ternary cements analysed in this study met the chemical, physical and mechanical requirements for the elaboration of future eco-efficient cements.Ministerio de Ciencia, Innovación y Universidades; RTI2018-097074-B-C21-2

    On the Performance of Interleavers for Quantum Turbo Codes

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    Quantum turbo codes (QTC) have shown excellent error correction capabilities in the setting of quantum communication, achieving a performance less than 1 dB away from their corresponding hashing bounds. Existing QTCs have been constructed using uniform random interleavers. However, interleaver design plays an important role in the optimization of classical turbo codes. Consequently, inspired by the widely used classical-to-quantum isomorphism, this paper studies the integration of classical interleaving design methods into the paradigm of quantum turbo coding. Simulations results demonstrate that error floors in QTCs can be lowered significantly, while decreasing memory consumption, by proper interleaving design without increasing the overall decoding complexity of the system

    Textural and chemical-mineralogical comparison of chondrules and matrix in ordinary and carbonaceous chondrites: Bechar 002 and Allende

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    Las condritas representan la materia meteorítica más primitiva del sistema solar. Su estudio aporta importantes claves mineralógicas y cosmoquímicas para comprender: a) los procesos que tuvieron lugar en las primeras etapas de su formación y b) su influencia en la composición de las superficies de otros planetas y lunas. Este trabajo presenta la caracterización textural y químico-mineralógica comparada de los cóndrulos y la matriz de dos tipos de condritas: la condrita ordinaria Bechar 002 (H6) y la condrita carbonácea de Allende (CV3). Los resultados obtenidos permiten conocer mejor las características de ambos ejemplares y confirman que han sido sometidas a procesos diferentes a partir de su formación en el cuerpo padre asteroidal: a) procesos de metamorfismo térmico y homogeneización y b) transformaciones secundarias debidas a alteración acuosaChondrites represent the most primitive meteoritic matter in the solar system. Their study provides essential mineralogical and cosmochemical keys to understand: a) the processes that occurred in the early stages of its formation and b) their role and significance influencing the composition of the surfaces of other planets and moons. This work presents a detailed comparison of the textural and chemical-mineralogical features of the chondrules and matrix of two types of chondrites: the Bechar 002 ordinary chondrite and the Allende carbonaceous chondrite. The results obtained allow knowing better the characteristics of both specimens, and confirm that they have undergone different processes after their formation in the asteroidal parent body: a) thermal processes of thermal metamorphism and homogeneization and b) secondary transformations due to aqueous alteration processe

    Comparing and modeling land use organization in cities

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    The advent of geolocated ICT technologies opens the possibility of exploring how people use space in cities, bringing an important new tool for urban scientists and planners, especially for regions where data is scarce or not available. Here we apply a functional network approach to determine land use patterns from mobile phone records. The versatility of the method allows us to run a systematic comparison between Spanish cities of various sizes. The method detects four major land use types that correspond to different temporal patterns. The proportion of these types, their spatial organization and scaling show a strong similarity between all cities that breaks down at a very local scale, where land use mixing is specific to each urban area. Finally, we introduce a model inspired by Schelling's segregation, able to explain and reproduce these results with simple interaction rules between different land uses.Comment: 9 pages, 6 figures + Supplementary informatio

    The meteorite collection of the National Museum of Natural Sciences, Madrid, Spain: An updated catalog

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    A catalog ofthe meteorite collection hosted by the National Museum ofNatural Sciences ofMadrid is presented. It includes 88 stony meteorites, 56 iron meteorites, and 13 stony-iron meteorites, as well as 14 tektites.Peer reviewe
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