1,720 research outputs found

    Two-dimensional Einstein manifolds in geometrothermodynamics

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    We present a class of thermodynamic systems with constant thermodynamic curvature which, within the context of geometric approaches of thermodynamics, can be interpreted as constant thermodynamic interaction among their components. In particular, for systems constrained by the vanishing of the Hessian curvature we write down the systems of partial differential equations. In such a case it is possible to find a subset of solutions lying on a circumference in an abstract space constructed from the first derivatives of the isothermal coordinates. We conjecture that solutions on the characteristic circumference are of physical relevance, separating them from those of pure mathematical interest. We present the case of a one-parameter family of fundamental relations that -- when lying in the circumference -- describe a polytropic fluid

    The KM3NeT multi-PMT optical module

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    The optical module of the KM3NeT neutrino telescope is an innovative multi-faceted large area photodetection module. It contains 31 three-inch photomultiplier tubes in a single 0.44m diameter pressure-resistant glass sphere. The module is a sensory device also comprising calibration instruments and electronics for power, readout and data acquisition. It is capped with a breakout-box with electronics for connection to an electro-optical cable for power and long-distance communication to the onshore control station. The design of the module was qualified for the first time in the deep sea in 2013. Since then, the technology has been further improved to meet requirements of scalability, cost-effectiveness and high reliability. The module features a sub-nanosecond timing accuracy and a dynamic range allowing the measurement of a single photon up to a cascade of thousands of photons, suited for the measurement of the Cherenkov radiation induced in water by secondary particles from interactions of neutrinos with energies in the range of GeV to PeV. A distributed production model has been implemented for the delivery of more than 6000 modules in the coming few years with an average production rate of more than 100 modules per month. In this paper a review is presented of the design of the multi-PMT KM3NeT optical module with a proven effective background suppression and signal recognition and sensitivity to the incoming direction of photons.French National Research Agency (ANR) ANR-15-CE31-0020 Centre National de la Recherche Scientifique (CNRS)Commission Europeenne (FEDER fund) Commission Europeenne (Marie Curie Program)Institut Universitaire de France (IUF)LabEx UnivEarthS ANR-10-LABX-0023 ANR-18-IDEX-0001Paris Ile-de-France Region, FranceShota Rustaveli National Science Foundation of Georgia (SRNSFG), Georgia FR-18-1268German Research Foundation (DFG)Greek Ministry of Development-GSRTIstituto Nazionale di Fisica Nucleare (INFN), Ministero dell'Universita e della Ricerca (MIUR), PRIN 2017 program, Italy NAT-NET 2017W4HA7SMinistry of Higher Education, Scientific Research and Innovation, MoroccoArab Fund for Economic and Social DevelopmentNederlandse organisatie voor Wetenschappelk Onderzoek (NWO), the NetherlandsNational Science Centre, Poland 2015/18/E/ST2/00758National Authority for Scientific Research (ANCS), RomaniaMinisterio de Ciencia, Innovacion, Investigacion y Universidades (MCIU): Programa Estatal de Generacion de Conocimiento PGC2018-096663-B-C41 PGC2018-096663-A C42 PGC2018-096663-B-C43 PGC2018-096663-B-C44Center for Forestry Research & Experimentation (CIEF) PROMETEO/2020/019Generalitat Valenciana: Grisolia program GRISOLIA/2018/119 GRISOLIA/2021/192 Generalitat Valenciana: GenT program CIDEGENT/2018/034 CIDEGENT/2019/043 CIDEGENT/2020/049 CIDEGENT/2021/023Junta de Andalucia AFQM-053-UGR18La Caixa Foundation LCF/BQ/IN17/11620019EU: MSC program, Spain 10102508

    Alternative mechanisms of p53 action during the unfolded protein response

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    The tumor suppressor protein p53 orchestrates cellular responses to a vast number of stresses, with DNA damage and oncogenic activation being some of the best described. The capacity of p53 to control cellular events such as cell cycle progression, DNA repair, and apoptosis, to mention some, has been mostly linked to its role as a transcription factor. However, how p53 integrates different signaling cascades to promote a particular pathway remains an open question. One way to broaden its capacity to respond to different stimuli is by the expression of isoforms that can modulate the activities of the full-length protein. One of these isoforms is p47 (p53/47, Δ40p53, p53ΔN40), an alternative translation initiation variant whose expression is specifically induced by the PERK kinase during the Unfolded Protein Response (UPR) following Endoplasmic Reticulum stress. Despite the increasing knowledge on the p53 pathway, its activity when the translation machinery is globally suppressed during the UPR remains poorly understood. Here, we focus on the expression of p47 and we propose that the alternative initiation of p53 mRNA translation offers a unique condition-dependent mechanism to differentiate p53 activity to control cell homeostasis during the UPR. We also discuss how the manipulation of these processes may influence cancer cell physiology in light of therapeutic approaches

    Inteligencia artificial en e-learning escenarios plausibles en Latinoamérica y nuevas competencias de egreso

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    Industry 4.0 as a result of the technological revolution reached an unprecedented impact worldwide; this transformation continues, now in search of an inclusive and just society, where smart technologies coexist under the control and for the service of human beings. Faced with this scenario, the university is responsible for training software engineers with autonomous and competitive profiles in artificial intelligence as a means of access to social and economic development in each country. A proposal of e-learning graduate competencies is proposed, after a prospective analysis of artificial intelligence in a virtual environment in Latin America

    Base Case Analysis of a HYSOL Power Plant

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    Concentrating solar power (CSP) plants are regarded as an alternative solution for electricity generation. The main drawback of this technology is related to the intermittent and seasonal nature of the solar irradiation. As a consequence, most CSP plants have a reduced capacity factor and difficulties to supply electricity on demand to the grid. The integration of energy back-up systems may contribute to increasing power generation capacity and stability. Several options are being developed at present which are based on the incorporation of Thermal Energy Storage (TES) and also the use of auxiliary fuels. HYSOL is a new concept in CSP technology that relies on the integration of a molten salt TES system operating in hybrid mode with a biogas turbine with a Heat Recovery System (HRS). This paper illustrates the methodology and first results obtained during the development of the static model, considering a Base Case of HYSOL configuration. The study of this Base Case allows evaluating the impact of HYSOL technology, providing preliminary plant information and defining the required tools to be used in the project

    Automated surgical margin assessment in breast conserving surgery using SFDI with ensembles of self-confident deep convolutional networks

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    With an adequate tissue dataset, supervised classification of tissue optical properties can be achieved in SFDI images of breast cancer lumpectomies with deep convolutional networks. Nevertheless, the use of a black-box classifier in current ex vivo setups provides output diagnostic images that are inevitably bound to show misclassified areas due to inter- and intra-patient variability that could potentially be misinterpreted in a real clinical setting. This work proposes the use of a novel architecture, the self-introspective classifier, where part of the model is dedicated to estimating its own expected classification error. The model can be used to generate metrics of self-confidence for a given classification problem, which can then be employed to show how much the network is familiar with the new incoming data. A heterogenous ensemble of four deep convolutional models with self-confidence, each sensitive to a different spatial scale of features, is tested on a cohort of 70 specimens, achieving a global leave-one-out cross-validation accuracy of up to 81%, while being able to explain where in the output classification image the system is most confident.Spanish Ministry of Science, Innovation and Universities (FIS2010-19860, TEC2016-76021-C2-2-R), Spanish Ministry of Economy, Industry and Competitiveness and Instituto de Salud Carlos III (DTS17-00055, DTS15- 00238), Instituto de Investigación Valdecilla (INNVAL16/02, INNVAL18/23), Spanish Ministry of Education, Culture, and Sports (FPU16/05705)

    Comparative analysis of cancer genes in the human and chimpanzee genomes

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    BACKGROUND: Cancer is a major medical problem in modern societies. However, the incidence of this disease in non-human primates is very low. To study whether genetic differences between human and chimpanzee could contribute to their distinct cancer susceptibility, we have examined in the chimpanzee genome the orthologous genes of a set of 333 human cancer genes. RESULTS: This analysis has revealed that all examined human cancer genes are present in chimpanzee, contain intact open reading frames and show a high degree of conservation between both species. However, detailed analysis of this set of genes has shown some differences in genes of special relevance for human cancer. Thus, the chimpanzee gene encoding p53 contains a Pro residue at codon 72, while this codon is polymorphic in humans and can code for Arg or Pro, generating isoforms with different ability to induce apoptosis or interact with p73. Moreover, sequencing of the BRCA1 gene has shown an 8 Kb deletion in the chimpanzee sequence that prematurely truncates the co-regulated NBR2 gene. CONCLUSION: These data suggest that small differences in cancer genes, as those found in tumor suppressor genes, might influence the differences in cancer susceptibility between human and chimpanzee. Nevertheless, further analysis will be required to determine the exact contribution of the genetic changes identified in this study to the different cancer incidence in non-human primates

    Protective Effect of Melatonin Against Mitomycin C-Induced Genotoxic Damage in Peripheral Blood of Rats

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    Mitomycin C (MMC) generates free radicals when metabolized. We investigated the effect of melatonin against MMC-induced genotoxicity in polychromatic erythrocytes and MMC-induced lipid peroxidation in brain and liver homogenates. Rats (N = 36) were classified into 4 groups: control, melatonin, MMC, and MMC + melatonin. Melatonin and MMC doses of 10 mg/kg and 2 mg/kg, respectively, were injected intraperitoneally. Peripheral blood samples were collected at 0, 24, 48, 72, and 96 hours posttreatment and homogenates were obtained at 96 hours posttreatment. The number of micronucleated polychromatic erythrocytes (MN-PCE) per 1000 PCE was used as a genotoxic marker. Malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA) levels were used as an index of lipid peroxidation. The MMC group showed a significant increase in MN-PCE at 24, 48, 72, and 96 hours that was significantly reduced with melatonin begin coadministrated. No significant differences were found in lipid peroxidation. Our results indicate that MMC-induced genotoxicity can be reduced by melatonin

    Soil erosion in vineyard under intense rainfall events

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    Abstract: S imulated rainfall experiments (68.2 mm h -1 ) on plots of 1 m 2 on two vineyards in Utiel and Moixent show high soil erosion rates. These measuremen ts show that runoff rates and sediment concentration are very high due to the bare soils. Soil losses are 5.68 and 23.14 Mg ha -1 h -1 , respectively, in the study areas and Moixent and Utie l. It is confirmed that the vineyards contribute to highly erodible soils.Unión Europea GL2008-02879/BTEUnión Europea LEDDRA 243857Unión Europea RECARE FP7 60349
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