11,676 research outputs found

    Nash Equilibria in the Response Strategy of Correlated Games

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    In nature and society problems arise when different interests are difficult to reconcile, which are modeled in game theory. While most applications assume uncorrelated games, a more detailed modeling is necessary to consider the correlations that influence the decisions of the players. The current theory for correlated games, however, enforces the players to obey the instructions from a third party or "correlation device" to reach equilibrium, but this cannot be achieved for all initial correlations. We extend here the existing framework of correlated games and find that there are other interesting and previously unknown Nash equilibria that make use of correlations to obtain the best payoff. This is achieved by allowing the players the freedom to follow or not to follow the suggestions of the correlation device. By assigning independent probabilities to follow every possible suggestion, the players engage in a response game that turns out to have a rich structure of Nash equilibria that goes beyond the correlated equilibrium and mixed-strategy solutions. We determine the Nash equilibria for all possible correlated Snowdrift games, which we find to be describable by Ising Models in thermal equilibrium. We believe that our approach paves the way to a study of correlations in games that uncovers the existence of interesting underlying interaction mechanisms, without compromising the independence of the players

    The MSSM from Scherk-Schwarz Supersymmetry Breaking

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    We present a five-dimensional model compactified on an interval where supersymmetry is broken by the Scherk-Schwarz mechanism. The gauge sector propagates in the bulk, two Higgs hypermultiplets are quasilocalized, and quark and lepton multiplets localized, in one of the boundaries. The effective four-dimensional theory is the MSSM with very heavy gauginos, heavy squarks and light sleptons and Higgsinos. The soft tree-level squared masses of the Higgs sector can be negative and they can (partially) cancel the positive one-loop contributions from the gauge sector. Electroweak symmetry breaking can then comfortably be triggered by two-loop radiative corrections from the top-stop sector. The fine tuning required to obtain the electroweak scale is found to be much smaller than in the MSSM, with essentially no fine-tuning for few TeV gaugino masses. All bounds from direct Higgs searches at LEP and from electroweak precision observables can be satisfied. The lightest supersymmetric particle is a (Higgsino-like) neutralino that can accomodate the abundance of Dark Matter consistently with recent WMAP observations.Comment: 23 pages, 3 figure

    Corrections to the Boltzmann mean free path in disordered systems with finite size scatterers

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    The mean free path is an essential characteristic length in disordered systems. In microscopic calculations, it is usually approximated by the classical value of the elastic mean free path. It corresponds to the Boltzmann mean free path when only isotropic scattering is considered, but it is different for anisotropic scattering. In this paper, we work out the corrections to the so called Boltzmann mean free path due to multiple scattering effects on finite size scatterers, in the s-wave approximation, ie. when the elastic mean free path is equivalent to the Boltzmann mean free path. The main result is the expression for the mean free path expanded in powers of the perturbative parameter given by the scatterer density.Comment: 12 page

    Pressure effect in the X-ray intrinsic position resolution in noble gases and mixtures

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    A study of the gas pressure effect in the position resolution of an interacting X- or gamma-ray photon in a gas medium is performed. The intrinsic position resolution for pure noble gases (Argon and Xenon) and their mixtures with CO2 and CH4 were calculated for several gas pressures (1-10bar) and for photon energies between 5.4 and 60.0 keV, being possible to establish a linear match between the intrinsic position resolution and the inverse of the gas pressure in that energy range. In order to evaluate the quality of the method here described, a comparison between the available experimental data and the calculated one in this work, is done and discussed. In the majority of the cases, a strong agreement is observed

    Personality and Transplantation

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    A associação entre o tipo de personalidade e vários aspectos relacionados com a doença médica tem sido objecto de abundante investigação. Os modelos teóricos de personalidade que, hoje em dia, são mais utilizados neste contexto são de dois tipos: o modelo de três factores (Neuroticismo, Extroversão e Psicoticismo) e o modelo de 5 factores (neuroticismo e extroversão, a conscenciosidade, agradabilidade, e a abertura à experiência). Os modelos que relacionam a personalidade com a doença médica situam-se entre três tipologias: Hiperreactividade induzida pela personalidade, Predisposição constitucional e Comportamentos deletérios induzidos pela personalidade. Na avaliação da personalidade no doente médico pode optar-se por vários tipos de abordagem: Abordagem Taxonómica vs Dimensional; Auto vs Hetero avaliação; Instrumentos específicos para uma população vs Inespecíficos. São explorados os argumentos que favorecem as várias formas de abordagem. Entre os vários instrumentos disponíveis para avaliar a personalidade destacam-se o NEO-PI nas suas diferentes versões (NEO-PI original, NEO-PI-R, NEO-FFI-60). O NEO-PI-R e o NEO-FFI-60 estão validados para a população portuguesa. Dos poucos estudos disponíveis sobre personalidade no transplante foi possível concluir que o neuroticismo se associava a uma menor qualidade de vida (física, mental, social) no período pós-transplante e a extroversão a uma maior qualidade de vida (física, social), que a personalidade de tipo D se associava a uma pior qualidade de vida e uma maior mortalidade e taxa de rejeição após o transplante e que as perturbações de personalidade não estavam relacionadas com um aumento da taxa de recaída no consumo de álcool em doentes transplantados por doença hepática alcoólica

    Repeated temperature logs from the sites of the Czech, Slovenian and Portuguese borehole climate stations

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    International audienceTwo borehole climate stations were established in Slovenia and Portugal within a joint Czech-Slovenian-Portuguese project in the years 2003?2005. They completed the older Czech station, which has been operating since the year 1994. We report here on the repeated temperature logs carried out within 6 boreholes at the sites of the stations and their surroundings within a time span of 8?20 years (1985?2005). The repeated logs revealed subsurface warming in all the boreholes amounting to 0.2?0.6°C below the depth of the annual run at 20 m. The depth of the Czech borehole (140 m) and the Portuguese borehole (180 m) was sufficient enough for a reconstruction of the ground surface temperature (GST) history of the last 150?200 years and their comparison with the surface air temperature (SAT) series measured in Prague (since 1771) and Lisbon (1856), respectively. The reconstructed histories reproduce reasonably well the amplitude of the recent warming, 1?1.5°C above the long-term mean. The depth of all four Slovenian boreholes, 100 m, did not allow the inversion, but it was possible to apply it to a deep borehole 5 km apart from the Slovenian station. The obtained GST history was compared with SAT series from Ljubljana (since 1851). Alternatively, a compatibility of the observed temporal changes of subsurface temperature with surface air temperature series measured in Prague, Ljubljana and Lisbon was checked by comparing differences of the repeated logs with the synthetic ones. These were calculated by using the SAT series as a forcing function at a surface of transient geothermal models of the borehole sites. A degree of agreement varies from very well to rather poor, probably depending on unaccounted site specific factors, which are to be specified by a long-term temperature monitoring at the established stations

    Repeated temperature logs from Czech, Slovenian and Portuguese borehole climate observatories

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    Two borehole climate observatories were established in Slovenia and Portugal within a joint Czech-Slovenian-Portuguese project in the years 2003-2005. Together with the older Czech observatory, which has been operating since the year 1994, they monitor air, soil and bedrock temperatures with the aim of studying air-ground coupling and the downward propagation of the surface temperature changes. We report here on repeated temperature logs carried out within 6 boreholes at the sites of the observatories and their surroundings within a time span of 8–20 years (1985–2005). The repeated logs revealed subsurface warming in all the boreholes amounting to 0.2–0.6°C below 20 m depth. The compatibility of the observed temporal changes of subsurface temperature with surface air temperature (SAT) series measured in Prague (since 1771), Ljubljana (since 1851) and Lisbon (since 1856) was checked by comparing repeated temperature logs with synthetic profiles that were calculated using SAT series as forcing functions. The depth of the Czech borehole (140 m) and the Portuguese borehole (180 m) was sufficient for a reconstruction of the ground surface temperature (GST) history of the last 150–200 years. Reconstructed GSTs were compared with the SAT series measured in Prague and Lisbon, respectively. The reconstructed histories reproduce reasonably well the amplitude of the recent warming inferred from the meteorological data, 1–1.5°C above the long-term mean. The depth (100 m) of the four repeatedly logged Slovenian boreholes was too shallow for inversion, but a climatic reconstruction was carried out for a deeper borehole, logged in 2006 and located within 5 km from the Slovenian observatory. The obtained GST history was compared with SAT series from Ljubljana

    Superação da dormência de sementes de gravioleira (Annona muricata L.).

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    Alternativas de substratos para a formação de porta-enxertos de gravioleira (Annona muricata) em tubetes.

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    As pesquisas realizadas com tubetes têm estudado predominantemente a composição do substrato, uma vez que, além de proporcionar boas condições para o desenvolvimento das mudas, ele deve promover adequada integração com o sistema radicular e não deve ficar aderido ao recipiente, a fim de possibilitar com eficiência a sua remoção e manuseio por ocasião do plantio.bitstream/CNPAT/7881/1/ct_67.pd

    Childhood social adversity and clustering of health risk behaviours during early adolescence in a population-based birth cohort

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    Objectives: This study aimed to prospectively explore the association between early lifetime exposure to psychosocial adversity and engagement in health risk behaviours (HRBs) during early adolescence. Study design: This was a prospective study. Methods: This study used data from the baseline (2005-2006), third (2016-2017) and fourth waves (2018-2020) of the Generation XXI birth cohort. Socio-economic circumstances (SECs) at baseline, adverse childhood experiences (ACEs; e.g. abuse, neglect, household dysfunction) at age 10 years and HRBs (i.e. alcohol consumption, smoking, physical exercise level, sedentary behaviours, sleep duration and eating behaviours) at age 13 years were measured. Patterns of HRBs were obtained using latent class analysis. Latent class regression analysis was used to estimate the likelihood of being engaged in HRBs according to the extent of exposure to ACEs (i.e. 0 ACEs, 1-3 ACEs, 4-5 ACEs and & GE;6 ACEs) and negative family SECs. Results: Adolescents whose mothers had a low level of education (adjusted odds ratio [aOR] = 2.72 [95% confidence interval {CI}, 2.33-3.18]), low occupational status (aOR = 3.21 [95% CI, 2.68-3.85]) and low income (aOR = 2.70 [95% CI, 2.23-3.28]) were more likely to be engaged in HRBs than their peers with higher SECs. Adolescents who experienced more ACEs were at a significantly increased risk of involve-ment in HRBs (aOR = 1.86 [95% CI, 1.33-2.63] for 4-5 ACEs vs aOR 2.41 [95% CI, 1.72-3.43] for & GE;6 ACEs). No significant gender differences were observed. Conclusions: Adolescents from families with low SECs were more likely than their more affluent coun-terparts to be engaged in HRBs. Furthermore, more ACEs contributed to widening health inequalities. & COPY; 2023 The Author(s). Published by Elsevier Ltd on behalf of The Royal Society for Public Health. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).This work was supported by the European Regional Development Fund through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology (FCT) , Portuguese Ministry of Science, Technology, and Higher Education under the projects HIneC: When do health inequalities start? Understanding the impact of childhood social adversity on health trajectories from birth to early adolescence (POCI-01-0145-FEDER-029567; reference: PTDC/SAU-PUB/29567/2017) . It is also supported by Unidade de Investigacao em Epidemiologia-Instituto de Saude Publica da Universidade do Porto (EPIUnit) (UIDB/04750/2020) , Laboratorio para a Investigacao Integrativa e Translacional (ITR) , Porto, Portugal (LA/P/0064/2020) , PhD grant SFRH/BD/144503/2019 (to A.A.) funded by FCT through Fundo Social Europeu, and FCT Investigator contract CEECIND/01516/2017 (to S.F.)
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