3,808 research outputs found

    Understanding the impact of line-of-sight in the ergodic spectral efficiency of cellular networks

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    In this paper we investigate the impact of lineof-sight (LoS) condition in the ergodic spectral efficiency of cellular networks. To achieve this goal, we have considered the kappa-mu shadowed model, which is a general model that provides an excellent fit to a wide set of propagation conditions. To overcome the mathematical complexity of the analysis, we have split the analysis between large and small-scale effects. Building on the proposed framework, we study a number of scenarios that range from heavily-fluctuating LoS to deterministic-LoS. Finally, we shed light on the interplay between fading severity and spectral efficiency by means of the amount of fading.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Swift heavy ion damage to sodium chloride: synergy between excitation and thermal spikes

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    Systematic data on the effect of irradiation with swift ions (Zn at 735 MeV and Xe at 929 MeV) on NaCl single crystals have been analysed in terms of a synergetic two-spike approach (thermal and excitation spikes). The coupling of the two spikes, simultaneously generated by the irradiation, contributes to the operation of a non-radiative exciton decay model as proposed for purely ionization damage. Using this scheme, we have accounted for the π-emission yield of self-trapped excitons and its temperature dependence under ion-beam irradiation. Moreover, the initial production rates of F-centre growth have also been reasonably simulated for irradiation at low temperatures ( < 100 K), where colour centre annealing and aggregation can be neglected

    Numerical simulations of thixotropic semi-solid aluminium alloys in open-rotor and rotor-stator mixers

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    This research uses the Bautista-Manero-Puig (BMP) model to examine flow patterns of semi-solid aluminium alloys (Al) in open-rotor and stator-rotor mixers via numerical solutions. The model captures the distinct thixo-viscoelastic behavior of the Al-alloys at low temperatures, near melting point. The analysis involves using 2D structured-meshes for open-rotor and rotor-stator geometries. Solutions for Newtonian and thixo-viscoelastic model fluids are reported through fields of velocity, strain-rate, stress, fluidity, and streamlines, revealing distinct features. Findings reveal nonlinear thixo-viscoelastic vortex patterns that vary with rotational speed, resulting in different fluidity and stress profiles compared to the invariant response of Newtonian fluids. At lower rotational speeds, rotor-pallets are dominated by structured material that gradually becomes unstructured to cover the outer vessel walls. When including a stator, the inner stator region resembles the Newtonian solution, but the outflow through stator gaps is reduced due to flow-structure levels outside. This information is of interest for industrial design and optimization of molten Al-alloy processing.Programa de Transferencia de Tecnología de la DFB FEDER Consejo Nacional de Ciencias, Humanidades y Tecnologı́as (CONAHCYT, Mexico) Universidad Nacional Autónoma de México UNA

    Nuevos retos moleculares en la conservación animal

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    The contribution of genetics to wildlife conservation has been stressed often forgetting the existing theoretical and empirical limitations in the use of genetic information to solve ecological and demographic problems. The possibilities of molecular analyses are extensive and the automation of procedures is increasing the efficiency and reducing the cost of molecular technology. With large amounts of molecular data already available, the interest is switching towards the analysis of these data and the interpretation of genetic variability within and across species from a functional perspective. The understanding of the link between genetic variation and fitness or survival is essential in conservation biology and this understanding needs the combination of molecular data with non–molecular (e.g. physiological, behavioural and ecological) data. Progress in this promising field will depend on the trust and collaboration between molecular and field biologists.La contribución de la genética a la conservación de la vida salvaje ha sido enfatizada, olvidándose a menudo que existen limitaciones teóricas y empíricas sobre el uso de la información genética para solucionar problemas ecológicos y demográficos. Los análisis moleculares ofrecen numerosas posibilidades y la automatización de los procesos está incrementando la eficiencia y reduciendo los costes de la tecnología molecular. Con grandes cantidades de datos moleculares ya disponibles, el interés se está desplazando hacia el análisis de dichos datos y la interpretación de la variabilidad genética intraespecífica e interespecífica desde una perspectiva funcional. La comprensión del vínculo entre variabilidad genética y eficacia biológica o supervivencia es esencial en la biología de la conservación, requiriendo esta comprensión la combinación de datos moleculares con datos no moleculares (por ejemplo fisiológicos, de comportamiento y ecológicos). El progreso en este campo tan prometedor debe basarse en la confianza y la colaboración entre biólogos moleculares y de campo

    The Non-Canonical Wnt/PKC Pathway Regulates Mitochondrial Dynamics through Degradation of the Arm-Like Domain-Containing Protein Alex3

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    The regulation of mitochondrial dynamics is vital in complex cell types, such as neurons, that transport and localize mitochondria in high energy-demanding cell domains. The Armcx3 gene encodes a mitochondrial-targeted protein (Alex3) that contains several arm-like domains. In a previous study we showed that Alex3 protein regulates mitochondrial aggregation and trafficking. Here we studied the contribution of Wnt proteins to the mitochondrial aggregation and dynamics regulated by Alex3. Overexpression of Alex3 in HEK293 cells caused a marked aggregation of mitochondria, which was attenuated by treatment with several Wnts. We also found that this decrease was caused by Alex3 degradation induced by Wnts. While the Wnt canonical pathway did not alter the pattern of mitochondrial aggregation induced by Alex3, we observed that the Wnt/PKC non-canonical pathway regulated both mitochondrial aggregation and Alex3 protein levels, thereby rendering a mitochondrial phenotype and distribution similar to control patterns. Our data suggest that the Wnt pathway regulates mitochondrial distribution and dynamics through Alex3 protein degradation

    High prevalence and diversity of extended-spectrum β-lactamase and emergence of OXA-48 producing Enterobacterales in wildlife in Catalonia

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    The contract of LMG was supported by the Instituto Nacional de Investigaci?n y Tecnolog?a Agraria y Alimentaria (INIA) and the European Social Fund. AV was supported by a PIF grant from the Universitat Aut?noma de Barcelona. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Our grateful thanks to the Torreferrussa WRC staff. A.C. was student of the Master?s Degree in Zoonosis and One Health (UAB). The authors are also grateful to the Centres de Recerca de Catalunya (CERCA) Programme.Most of the studies focused on antimicrobial resistance (AMR) performed in wildlife describe Escherichia coli as the principal indicator of the selective pressure. In the present study, several species of Enterobacterales with a large panel of cephalosporin resistant (CR) genes have been isolated from wildlife in Catalonia. A total of 307 wild animals were examined to determine the prevalence of CR enterobacteria, AMR phenotypes and the presence of common carbapenem and CR genes. The overall prevalence of CR-phenotype was 13% (40/ 307): 17.3% in wild mammals (18/104) and 11.5% in wild birds (22/191) (p<0.01). Hedgehogs showed the highest prevalence (13.5% of 104) of the mammal specimens, and raptors the highest in bird specimen (7.3% of 191). Although CR E. coli was the most frequently isolated (45%), other CR- Enterobacterales like Klebsiella pneumoniae (20%), Citrobacter freundii (15%), Enterobacter cloacae (5%), Proteus mirabilis (5%), Providencia spp (5%) and Serratia marcescens (2.5%) were also isolated. A high diversity of CR genes was identified among the isolates, with 50% yielding blaCMY-2, 23% blaSHV-12, 20% blaCMY-1 and 18% blaCTX-M-15. Additionally, resistance to carbapenems associated to OXA-48 gene was found. Most of the CR isolates, principally K. pneumoniae and C. freundii, were multiresistant with co-resistance to fluoroquinolones, tetracycline, sulphonamides and aminoglycosides. This study reports high prevalence of Enterobacterales harbouring a variety of CR genes and OXA-48 mediated-carbapenem resistance, all of them frequently associated to nosocomial human infections, for the first time in wild mammals and wild birds. Implementation of control measures to reduce the impact of anthropogenic pressure in the environment is urgently needed

    Prosopis, Retama monosperma. Phragmites y Arundo donax en cosechas sucesivas a uno y dos años de crecimiento, para la elaboración de pasta celulósica y papel

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    Se evalúa la aptitud de ciertas especies regeneradoras de terrenos degradados: Prosopis (variedades: alba y juliflora),Retama monosperma, Phragmites y Arundo donax, para la fabricación de pastas celulósicas y hojas de papel, mediante un proceso de pasteo organosolv alcalino. Se caracterizan y comparan las materias primas, pastas celulósicas y hojas de papel, para cosechas de un año (más rebrotes de un año de edad, después de haberlas cortado al año) y dos años de crecimiento. Las especies Retama monosperma, Phragmites y Arundodonax muestran potencialidad para su aprovechamientoindustrial, en cosechas de corta rotación, para la obtenciónde pastas celulósicas y papel. Los números kappa de las pastas de 2º año están entre 10,3 y 12,6, con números de tracción entre 13,7 y 20,9 kNm·kg–1 en las pastas sin refinar. Sin embargo la explotación industrial de las dos variedades de Prosopis precisaría su adecuación a tiempos de explotación más largos, que los estudiados en este trabajo

    Resiliencia en profesionales de la intervención social

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    La resiliencia es un concepto con un enorme potencial para todas aquellas profesiones que reconocen en su objeto de intervención la prevención basada en las fortalezas y recursos propios de las personas y del entorno con el que se relacionan. En base a ello, existen numerosas investigaciones que analizan el papel de la intervención social y de sus profesionales en la construcción de la resiliencia de los individuos, grupos y comunidades hacia los que dirigen su actuación. Sin embargo, son menos frecuentes los trabajos de teorización e investigación centrados en el desarrollo y construcción de esta misma capacidad resiliente en los propios profesionales y en las implicaciones que de ello se deriva para su práctica profesional y para las organizaciones en las que se encuentran. Con el objetivo principal de analizar la presencia de la resiliencia en los profesionales de la intervención social frente a la de otros profesionales no relacionados con la ayuda social, se lleva a cabo una investigación de corte transversal en la que participan 366 sujetos, trabajadores sociales y otros profesionales – informáticos, ingenieros, trabajadores manuales y de servicios- todos ellos de la provincia de Málaga. Se analizan los diferentes los componentes de la resiliencia, siguiendo el modelo de Grotberg (1995). Los resultados apuntan hacia el colectivo de trabajadores sociales como más resilientes que el resto de profesionales.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Using LDGM Codes and Sparse Syndromes to Achieve Digital Signatures

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    In this paper, we address the problem of achieving efficient code-based digital signatures with small public keys. The solution we propose exploits sparse syndromes and randomly designed low-density generator matrix codes. Based on our evaluations, the proposed scheme is able to outperform existing solutions, permitting to achieve considerable security levels with very small public keys.Comment: 16 pages. The final publication is available at springerlink.co
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