3,698 research outputs found

    Probing non-unitary mixing and CP-violation at a Neutrino Factory

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    A low energy non-unitary leptonic mixing matrix is a generic feature of many extensions of the Standard Model. In such a case, the task of future precision neutrino oscillation experiments is more ambitious than measuring the three mixing angles and the leptonic (Dirac) CP-phase, i.e., the accessible parameters of a unitary leptonic mixing matrix. A non-unitary mixing matrix has 13 parameters that affect neutrino oscillations, out of which four are CP-violating. In the scheme of Minimal Unitarity Violation (MUV) we analyse the potential of a Neutrino Factory for determining or constraining the parameters of the non-unitary leptonic mixing matrix, thereby testing the origin of CP-violation in the lepton sector.Comment: 21 pages, 8 eps figures, REVTeX

    Abrupt wind regime changes in the North Atlantic Ocean during the past 30,000-60,000 years

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    The inputs of higher plants in Blake Outer Ridge (subtropical western North Atlantic) during marine isotope stage 3 (MIS3) have been recorded at high resolution by quantification of C23–C33 odd carbon numbered n-alkanes and C20–C30 even carbon numbered n-alkan-1-ols in sediment sections of Ocean Drilling Program Site 1060. The changes of these proxies at this open marine site are mainly related to eolian inputs. Their concentrations and fluxes exhibit major abrupt variations that are correlated with Dansgaard/Oeschger (D/O) patterns in Greenland ice cores. The ratios between interstadials and stadials range between 2 and 9 times. The intense flux increases in the D/O stadials are linked to strong enhancements of the westerly wind regime at these subtropical latitudes during stadials. The observed variation was paralleled by changes in wind-blown dust and the polar circulation index in Greenland ice, which is in agreement with previously hypothesized atmospheric teleconnections between northern and middle-low latitudes of the Northern Hemisphere. The close correspondence between sedimentary and ice core proxies is evidence that crossings of the glacial climate thresholds involved major reorganizations of the troposphere. The observed large rise in higher plant biomarkers indicates that climate stabilization in the D/O stadial conditions led to main increases in wind intensity

    Emotional Capital in Family Businesses: Decisions from Human Resource Management Perspective

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    Nowadays, family businesses (FBs) have become a distinctive organizational model, not only for preserving the values of their founders in times of technological, political and economical changes but also for fostering a different kind of organization surrounded by emotional ties. This is particularly interesting to the human resource management (HRM) area, because managers must take decisions aimed at achieving economic and financial goals, which often affect the emotional stability of family members. Regarding this issue, the term emotional capital (EC) appears as a set of assets based on the emotions that the organization has developed over time with their employees. This chapter examines, from the HRM perspective, how human resource choices can be affected in order to preserve a positive EC for organizations. Due to the social implications emotions have in HRM, the chapter also links corporate social responsibility (CSR) as an important management strategy, focused on meeting employees and social concerns, as a way to strengthen the emotional bonds in companies. The literature review and institutional reports pointed the characteristics of FB in Spain, describing how companies could design human resource policies and practices aimed at keeping EC. Finally, the configurational approach of HRM is used to explain the design of the best possible human resource practices adapted to a particular context like FB

    Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios

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    The impact of climate change on the habitat suitability for large brown trout (Salmo trutta L.) was studied in a segment of the Cabriel River (Iberian Peninsula). The future flow and water temperature patterns were simulated at a daily time step with M5 models' trees (NSE of 0.78 and 0.97 respectively) for two short-term scenarios (2011 2040) under the representative concentration pathways (RCP 4.5 and 8.5). An ensemble of five strongly regularized machine learning techniques (generalized additive models, multilayer perceptron ensembles, random forests, support vector machines and fuzzy rule base systems) was used to model the microhabitat suitability (depth, velocity and substrate) during summertime and to evaluate several flows simulated with River2D©. The simulated flow rate and water temperature were combined with the microhabitat assessment to infer bivariate habitat duration curves (BHDCs) under historical conditions and climate change scenarios using either the weighted usable area (WUA) or the Boolean-based suitable area (SA). The forecasts for both scenarios jointly predicted a significant reduction in the flow rate and an increase in water temperature (mean rate of change of ca. −25% and +4% respectively). The five techniques converged on the modelled suitability and habitat preferences; large brown trout selected relatively high flow velocity, large depth and coarse substrate. However, the model developed with support vector machines presented a significantly trimmed output range (max.: 0.38), and thus its predictions were banned from the WUA-based analyses. The BHDCs based on the WUA and the SA broadly matched, indicating an increase in the number of days with less suitable habitat available (WUA and SA) and/or with higher water temperature (trout will endure impoverished environmental conditions ca. 82% of the days). Finally, our results suggested the potential extirpation of the species from the study site during short time spans.The study has been partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) - Spanish MINECO (Ministerio de Economia y Competitividad) - and FEDER funds and by the Confederacion Hidrografica del Jucar (Spanish Ministry of Agriculture, Food and Environment). We are grateful to the colleagues who worked in the field and in the preliminary data analyses, especially Juan Diego Alcaraz-Henandez, David Argibay, Aina Hernandez and Marta Bargay. Thanks to Matthew J. Cashman for the academic review of English. Finally, the authors would also to thank the Direccion General del Agua and INFRAECO for the cession of the trout data. The authors thank AEMET and UC by the data provided for this work (dataset Spain02).Muñoz Mas, R.; López Nicolás, AF.; Martinez-Capel, F.; Pulido-Velazquez, M. (2016). Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios. Science of the Total Environment. 544:686-700. https://doi.org/10.1016/j.scitotenv.2015.11.14768670054

    La autoeficacia como recurso en el proceso de socialización laboral. Una propuesta de intervención

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    Actualmente hay un gran número de empresas que se están dando cuenta de la importancia de gestionar correctamente la incorporación de nuevos empleados en sus plantillas. Y es que este proceso es de una gran complejidad y puede tener fuertes repercusiones tanto en la salud psicosocial de los trabajadores como en la salud financiera de la organización. Consideramos que la autoeficacia de los nuevos empleados puede estar jugando un papel fundamental en la adaptación de estos a su nuevo entorno. Es por ello que el objetivo de este programa es utilizar la autoeficacia como elemento central para facilitar la incorporación de nuevos trabajadores a la organización. Para ello, se realizarán cuatro talleres que incidirán en las cuatro fuentes principales de autoeficacia. Los primeros tres talleres se realizarán previamente a la incorporación de los nuevos trabajadores: 1) el diseño de tareas de menor a mayor dificultad, incidiendo en las experiencias de éxito; 2) la realización de un programa mentoring, que trata de actuar sobre el aprendizaje vicario; 3) la programación de reuniones de feedback y refuerzo, actuando de esta forma en la persuasión social. El último taller se realizará tras la incorporación de los nuevos trabajadores y consistirá en unas jornadas de bienvenida y en varias actividades de mindfulness, con lo que se pretenden facilitar los indicadores fisiológicos de calma y relajación. El éxito de este programa se basa en el abordaje de todas las fuentes de la autoeficacia, con la intención de crear sinergias entre estas y favorecer así la consecución de los objetivos de la intervención. Creemos que este tipo de programa puede reducir el estrés asociado a la incorporación al mercado laboral, especialmente cuando los trabajadores son recién titulados. Además, por la literatura existente, consideramos que existen evidencias suficientes para hipotetizar que el incremento en la autoeficacia laboral provocará, a su vez, el aumento del engagement y del bienestar en el trabajo, con lo que se utilizarán distintos cuestionarios para medir dichos constructos antes y tras la intervención. !A large number of companies are now realising the importance of properly managing the incorporation of new employees into their workforce. This process is highly complex and can have a strong impact on the psychosocial health of workers and the financial health of the organisation. We believe that the selfefficacy of new employees may be playing a key role in their adaptation to their new environment. That is why the aim of this programme is to use self-efficacy as a central element to facilitate the incorporation of new workers into the organisation. To this purpose, four workshops will be held that will focus on the four main sources of self-efficacy. The first three workshops will be held prior to the incorporation of new workers: 1) the design of tasks from least to most difficult, focusing on successful experiences; 2) the implementation of a mentoring program, which seeks to act on vicarious learning; 3) the scheduling of feedback and reinforcement meetings, thus acting in social persuasion. The last workshop will take place after the incorporation of the new workers and will consist of welcome days and various mindfulness activities, which are intended to facilitate physiological indicators of calm and relaxation. The success of this programme is based on addressing all sources of self-efficacy, with the intention of creating synergies between them, and thus promoting the achievement of the objectives of the intervention. We believe that this type of program can reduce the stress associated with entering the labor market, especially when workers are newly qualified. In addition, from the existing literature, we consider that there is sufficient evidence to hypothesize that the increase in labor self-efficacy, in turn, will provoke an increase in engagement and well-being at work, with which different questionnaires will be used to measure these constructs before and after the intervention

    Synthesis of pillared clays from metallic salts as pigments for thermosolar absorptive coatings

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    [EN] A general procedure for developing stable solar absorptive coatings at both high temperature and a high solar radiation concentration is presented. In order to generally improve thermal efficiency, a coating with high solar absorptance is applied all over the surface of receiver tubes that is subjected to extreme working conditions. Consequently, a durable coating with high absorptivity for sunlight is needed. An alternative paint formulation research and development line to Pyromark-2500, the paint currently used in many commercial solar thermal power plants (CSP) is proposed. Pigment synthesis is developed by intercalating metallic salts into laminar or tubular clay structures. Metallic pxides, which provide paint with its color properties, are obtained by a calcination process. Addition of silane or surfactants during the pigment synthesis is also optimized. Once dried and ground to a precise size, pigments are mixed with a commercial binder and applied to a metallic substrate to study their properties. Thermal stability to high temperature is studied with different tests. The results showed that laminar structure was preferred to intercalate larger amounts of metallic salt into the clay structure, and no significant differences were found when using silane or surfactant modifiers. Although the highest absorptivity value was 85% after 24 h at 600 degrees C, samples presented very good adherence to the metallic substrate. Addition of a small quantity of commercial black pigment to the paint composition could improve the absorptivity and maintain the excellent adhesion shown. Furthermore, montmorillonite clay, modified with a surfactant before adding metallic salt, and without silane, resulted in a black pigment in a powder form. This pillared clay could be used in future paint formulations. (C) 2017 Elsevier Ltd. All rights reserved.The research that has led to these results was funded by Abengoa Solar New Technologies S.A. by a private contract with the Colour and Vision Group of the University of Alicante.Micó Vicent, B.; López-Herraiz, M.; Bello, A.; Martínez, N.; Martinez-Verdu, FM. (2017). Synthesis of pillared clays from metallic salts as pigments for thermosolar absorptive coatings. Solar Energy. 155:314-322. doi:10.1016/j.solener.2017.06.034S31432215

    Pulsed interactions unify reaction-diffusion and spatial nonlocal models for biological pattern formation

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    The emergence of a spatially-organized population distribution depends on the dynamics of the population and mediators of interaction (activators and inhibitors). Two broad classes of models have been used to investigate when and how self-organization is triggered, namely, reaction-diffusion and spatially nonlocal models. Nevertheless, these models implicitly assume smooth propagation scenarios, neglecting that individuals many times interact by exchanging short and abrupt pulses of the mediating substance. A recently proposed framework advances in the direction of properly accounting for these short-scale fluctuations by applying a coarse-graining procedure on the pulse dynamics. In this paper, we generalize the coarse-graining procedure and apply the extended formalism to new scenarios in which mediators influence individuals' reproductive success or their motility. We show that, in the slow- and fast-mediator limits, pulsed interactions recover, respectively, the reaction-diffusion and nonlocal models, providing a mechanistic connection between them. Furthermore, at each limit, the spatial stability condition is qualitatively different, leading to a timescale-induced transition where spatial patterns emerge as mediator dynamics becomes sufficiently fast

    The Evolutionary Success of the Marine Bacterium SAR11 Analyzed through a Metagenomic Perspective

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    The SAR11 clade of Alphaproteobacteria is the most abundant group of planktonic cells in the near-surface epipelagic waters of the ocean, but the mechanisms underlying its exceptional success have not been fully elucidated. Here, we applied a metagenomic approach to explore microdiversity patterns by measuring the accumulation of synonymous and nonsynonymous mutations as well as homologous recombination in populations of SAR11 from different aquatic habitats (marine epipelagic, bathypelagic, and surface freshwater). The patterns of mutation accumulation and recombination were compared to those of other groups of representative marine microbes with multiple ecological strategies that share the same marine habitat, namely, Cyanobacteria (Prochlorococcus and Synechococcus), Archaea (“Candidatus Nitrosopelagicus” and Marine Group II Thalassoarchaea), and some heterotrophic marine bacteria (Alteromonas and Erythrobacter). SAR11 populations showed widespread recombination among distantly related members, preventing divergence leading to a genetically stable population. Moreover, their high intrapopulation sequence diversity with an enrichment in synonymous replacements supports the idea of a very ancient divergence and the coexistence of multiple different clones. However, other microbes analyzed seem to follow different evolutionary dynamics where processes of diversification driven by geographic and ecological instability produce a higher number of nonsynonymous replacements and lower intrapopulation sequence diversity. Together, these data shed light on some of the evolutionary and ecological processes that lead to the large genomic diversity in SAR11. Furthermore, this approach can be applied to other similar microbes that are difficult to culture in the laboratory, but abundant in nature, to investigate the underlying dynamics of their genomic evolution.This work was supported by grants VIREVO CGL2016-76273-P (AEI/FEDER, EU) (cofunded with FEDER funds) from the Spanish Ministerio de Economía, Industria, y Competitividad and HIDRAS3 PROMETEU/2019/009 from the Generalitat Valenciana to F.R.-V. and by grants CGL2013-40564-R and SAF2013-49267-EXP from the Spanish Ministerio de Economía, Industria, y Competitividad; grant ACIF/2015/332 from the Generalitat Valenciana; and grant 5334 from the Betty Moore Foundation to M.M.-G. F.R.-V. was also a beneficiary of the 5top100-program of the Ministry for Science and Education of Russia. J.M.H.-M. was supported by a Ph.D. fellowship from the Spanish Ministerio de Economía y Competitividad (BES-2014-067828). F.H.C. was supported by a postdoctoral fellowship from the Generalitat Valenciana (APOSTD/2018/186). M.L.-P. was supported by a postdoctoral fellowship from the Spanish Ministerio de Economía, Industria, y Competitividad (IJCI-2017-34002)
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