456 research outputs found

    A formula for the Bloch vector of some Lindblad quantum systems

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    Using the Bloch representation of an N-dimensional quantum system and immediate results from quantum stochastic calculus, we establish a closed formula for the Bloch vector, hence also for the density operator, of a quantum system following a Lindblad evolution with selfadjoint Lindblad operators.Comment: Accepted in Phys. Lett. A (shorter version than original

    Jet measurements in the ALICE experiment at the LHC

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    Jet tomography probes provide a means to explore the properties of highly compressed and excited nuclear matter created in heavy ion collisions. The capabilities of the ALICE experiment, with its electromagnetic calorimeter (EMCal) upgrade, to trigger on and reconstruct jets in p+p and Pb+Pb collisions at sNN\sqrt{s_{NN}}=5.5 TeV are presented.Comment: 8 pages, 6 figures. Presented at the IX International Conference on Nucleus-Nucleus Collisions, Rio de Janeiro, Brazil, August 28 - September 1, 200

    Modelo de implementación de proyectos de Transformación Digital en Hoteles Boutique

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    Digital transformation has become an imperative of competitiveness for companies. However, there is a knowledge gap on the subject mainly in countries like Colombia and more in industry sectors where the use of information technologies has traditionally been low. In these sectors, although they recognize the advantages and needs of adopting digital transformation, it is not clear how and where to start. This research aims to provide knowledge to decision makers on how to adopt and initiate such transformation, select and validate an implementation model for digital transformation projects. The validation of the model was carried out in a set of boutique hotels in the city of Cartagena. © 2020 Latin American and Caribbean Consortium of Engineering Institutions. All rights reserved

    A new sauropod titanosaur from the Plottier Formation (Upper Cretaceous) of Patagonia (Argentina)

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    This paper presents a new titanosaur sauropod, collected from levels of reddish clays assigned to the Plottier Formation (Coniacian-Santonian). The holotype of Petrobrasaurus puestohernandezi gen. et. sp. nov. is a disarticulated specimen, from which teeth, cervical, dorsal and caudal vertebrae, sternal plates, metacarpals, femora, tibia, a fragment of ilium, pubis, haemal arches, and cervical and dorsal ribs have been preserved. This period is of particular interest because it saw the definitive isolation of the vertebrate faunas of Patagonia, with the separation of South America from the rest of Gondwana, a process that had begun during the Early Cretaceous. Although some of the characters observed in Petrobrasaurus gen. nov. suggest a relationship with the South American clade Lognkosauria, this new sauropod is regarded as Titanosauria incertae sedis until a more profound analysis of the Titanosauria that in which it is included is undertaken

    Simultaneous optimization of circadian and color performance for smart lighting systems design

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    We present in this work a method to design lighting sources that can be adapted to different temperatures of color and, simultaneously, with a tunable circadian character. We obtained an acceptable range of tuning in both parameters compared to the bibliography. This kind of lighting source has potential applications particularly in building lighting, but also in farming or agriculture. At the same time, we have shown the possibilities of multiobjective optimizations in the lighting industry. The optimization has been developed using the Genetic Algorithm and multiobjective merit functions. The lighting source is able to work under two different regimes regarding the circadian effect, with a design based on a combination of two monochromatic and two white Lighting Emitting Diodes (enough for controlling the circadian character and the color performance at the same time). A prototype, which can be manually or automatically controlled, has been also implemented and evaluated, with a performance in terms of color coordinates very close to the daylight, showing a modulation of the Circadian Efficacy of Radiation between 6% and 16%, and a Color Rendering Index above 80%

    Icnitas de dinosaurios saurópodos en la Formación Rayoso (Cuenca Neuquina, Albiense, Argentina)

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    Se describen por primera vez icnitas de dinosaurios saurópodos en la Formación Rayoso (Albiense) en Neuquén (Argentina). En dos afloramientos distintos del Miembro Rincón se han encontrado dos rastros de saurópodos con el paso estrecho. Uno de los rastros está formado por icnitas de pequeño tamaño, que podrían ser de un individuo juvenil. Otra posibilidad sería que los dos rastros sean de dos productores distintos. Los fósiles de dinosaurios son raros en la Formación Rayoso, evidencia posiblemente relacionada con su ambiente de depósito de gran aridez. Los diplodocoideos rebaquisáuridos son uno de los saurópodos más abundantes al final del Cretácico Inferior de la Cuenca Neuquina, de hecho los únicos dinosaurios conocidos en la Formación Rayoso pertenecen a esta familia. Se propone de manera tentativa que los rastros estudiados los produjeron diplodocoideos rebaquisáuridos, teniendo en cuenta el registro conocido y que los rastros de paso estrecho se asocian con diplodocoideos. Sauropod dinosaur tracks from the Rayoso Formation (Albian) in Neuquén (Argentina) are described for the first time. Evidence of two narrow-gauge sauropod trackways has been found in two distinct outcrops of the Rincón Member. One of the trackways consists of small-sized tracks and might belong to a juvenile individual. Another possibility is that the two trackways were produced by different species of sauropod. Dinosaur fossils are rare in the Rayoso Formation, possibly as a result of its arid depositional environment. Rebbachisaurid diplodocoids are one of the most abundant sauropods at the end of the Lower Cretaceous of the Neuquén Basin. Indeed, the only dinosaurs known from the Rayoso Formation belong to this family. Bearing in mind this exclusive presence and the association of narrow-gauge trackways with diplodocoids, it is tentatively proposed that the trackways under study were produced by rebbachisaurid diplodocoids

    Application of regulatory sequence analysis and metabolic network analysis to the interpretation of gene expression data

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    We present two complementary approaches for the interpretation of clusters of co-regulated genes, such as those obtained from DNA chips and related methods. Starting from a cluster of genes with similar expression profiles, two basic questions can be asked: 1. Which mechanism is responsible for the coordinated transcriptional response of the genes? This question is approached by extracting motifs that are shared between the upstream sequences of these genes. The motifs extracted are putative cis-acting regulatory elements. 2. What is the physiological meaning for the cell to express together these genes? One way to answer the question is to search for potential metabolic pathways that could be catalyzed by the products of the genes. This can be done by selecting the genes from the cluster that code for enzymes, and trying to assemble the catalyzed reactions to form metabolic pathways. We present tools to answer these two questions, and we illustrate their use with selected examples in the yeast Saccharomyces cerevisiae. The tools are available on the web (http://ucmb.ulb.ac.be/bioinformatics/rsa-tools/; http://www.ebi.ac.uk/research/pfbp/; http://www.soi.city.ac.uk/~msch/)

    Sustainable Materials and Biorefinery Chemicals from Agriwastes

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    This is an open access chapter distributed under the terms of the Creative Commons Attribution License.-- et al.Countries with economies based on agriculture generate vast amounts of low or null value wastes which may even represent an environmental hazard. In our group, agricultural industrial wastes have been converted into value added liquid substances and materials with several aims: decreasing pollution, giving added value to wastes and working in a sustainable manner in which the wastes of an industry can be used as the raw materials of the same or others, as the “cradle to cradle” philosophy states [1]. Sub-products from the agricultural food industry are being employed as renewable low cost raw materials in the preparation of Ecomaterials, designed for use in a number of industrial processes of great interest. Given their origin, these materials may compete with conventional ones since with this process a sustainable cycle is closed, in which the residues of one industry are used as raw materials in the same or other industries [2]. With regards to the composition of the residues produced from agriculture, the pH of soil is of great importance, since plants can only absorb the minerals that are dissolved in water and pH is mandatory for the physical, chemical and biological properties of soil and the main cause of many agronomic questions related to nutrient assimilation [3-5]. Variations of pH modify the solubility of most elements necessary for the development of crops and also influence the microbian activity of soil, which will affect the transformation of elements that are liberated to the soil and can be assimilated to form crops or not [3]. For example at pH lower than 6 or higher than 8 bacterian activities are lowered, the oxidation of nitrogen to nitrate is reduced and the amount of nitrogen available for plant food is decreased. However Al, Fe and manganese are more soluble at low pHs, reaching even toxic concentrations. Potassium and sulphur are easily adsorbed at pH higher than 6, calcium and magnesium between 7 and 8.5 and iron at pH lower than 6. For alkaline pH in soil, the availability of H2PO4-can be reduced through precipitation of phosphorous containing salts withcations such as calcium Ca2+ or magnesium Mg2+. However when soils have acid pH other compounds with HPO42-and iron (Fe2+), aluminium (Al3+) and manganese (Mn2+) can form, with increased solubility. The main factors that influence soil pH are the mineral composition and how it meteorizes, the decomposition of organic matter, how nutrients are partitioned among the solution and aggregates and of course the pluviometryof the zone and atmospheric contamination.Lower pHs are found in places with high pluviometry, with high organic matter decomposition, young soils developed on acid substrates, and places with high atmospheric contamination (acid rain). Depending on the species, crops can benefit from calcareous soils with high calcium carbonate content such as alfalfa, but other plants prefer soils with acid pH such as potatoes, coffee or tobacco. It is clear that different seasons will produce plants with a varying composition depending on the atmospheric conditions and therefore the materials derived from them need to be characterised and analysed to determine their possible uses.Given its multidisciplinary approach, this work is being carried out through the collaboration among national (Institute of Materials Science of Madrid (ICMM, CSIC), Institute of Catalysis (ICP, CSIC), Centre of Molecular Biology Severo Ochoa (UAM-CSIC), Polytechnic University of Madrid (UPM), University at distance (UNED), University Complutense of Madrid (UPM) and international (University of Sheffield and University of Ghent) research groups, in addition to various industries interested in the transformation of their residues and or sub-products into “value added materials”, with whom various research projects have been and are being sponsored by the MICINN and CDTI.Peer Reviewe

    Neutron star properties in the quark-meson coupling model

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    The effects of internal quark structure of baryons on the composition and structure of neutron star matter with hyperons are investigated in the quark-meson coupling (QMC) model. The QMC model is based on mean-field description of nonoverlapping spherical bags bound by self-consistent exchange of scalar and vector mesons. The predictions of this model are compared with quantum hadrodynamic (QHD) model calibrated to reproduce identical nuclear matter saturation properties. By employing a density dependent bag constant through direct coupling to the scalar field, the QMC model is found to exhibit identical properties as QHD near saturation density. Furthermore, this modified QMC model provides well-behaved and continuous solutions at high densities relevant to the core of neutron stars. Two additional strange mesons are introduced which couple only to the strange quark in the QMC model and to the hyperons in the QHD model. The constitution and structure of stars with hyperons in the QMC and QHD models reveal interesting differences. This suggests the importance of quark structure effects in the baryons at high densities.Comment: 28 pages, 10 figures, to appear in Physical Review
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