140 resultados para dark matter simulations


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In this article, I firstly offer a synthesis of a brief set of analytical elements of the theory of democracy and federalism established in the recent debate which identify a number of flaws in the normative and institutional bases of plurinational democracies. It is necessary to overcome these flaws in order to achieve a true political and constitutional recognition and accommodation of the national pluralism of this kind of liberal democracies (section 1). Secondly, we will focus on the Spanish case of the “Estado de las Autonomías” taking into account the recent reform of the Catalan constitutional law (Estatut d’autonomia 2006) (section 2). A final section makes a number of concluding remarks relating the previously highlighted elements of the theory of democracy and federalism with the analysis of the Catalan case (section 3).

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We first establish that policymakers on the Bank of England's Monetary PolicyCommittee choose lower interest rates with experience. We then reject increasingconfidence in private information or learning about the structure of the macroeconomy as explanations for this shift. Instead, a model in which voters signal theirhawkishness to observers better fits the data. The motivation for signalling is consistent with wanting to control inflation expectations, but not career concerns orpleasing colleagues. There is also no evidence of capture by industry. The papersuggests that policy-motivated reputation building may be important for explainingdynamics in experts' policy choices.

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We examine the relationship between institutions, culture and cyclical fluctuations for a sampleof 45 European, Middle Eastern and North African countries. Better governance is associated withshorter and less severe contractions and milder expansions. Certain cultural traits, such as lack ofacceptance of power distance and individualism, are also linked business cycle features. Businesscycle synchronization is tightly related to similarities in the institutional environment. Mediterraneancountries conform to these general tendencies.

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The representation of women in top corporate officer positions is steadily increasing. However, little is known about the impact this will have. A large literature documents that women are different from men in their choices and in their preferences, but most of this literature relies on samples of college students or workers at lower levels in the corporate hierarchy. If women must be like men to break the glass ceiling, we might expect gender differences to disappear among top executives. In contrast, using a large survey of all directors of publicly-traded corporations in Sweden, we show that female and male directors differ systematically in their core values and risk attitudes. While certain population gender differences disappear at the director level, others do not. Consistent with the findings for the Swedish population, female directors are more benevolent and universally concerned, but less power-oriented than men. However, they are less traditional and security-oriented than their male counterparts. Furthermore, female directors are slightly more risk-loving than male directors. This suggests that having a women on the board need not lead to more risk-averse decision-making.

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We study the contribution of money to business cycle fluctuations in the US,the UK, Japan, and the Euro area using a small scale structural monetary business cycle model. Constrained likelihood-based estimates of the parameters areprovided and time instabilities analyzed. Real balances are statistically importantfor output and inflation fluctuations. Their contribution changes over time. Models giving money no role provide a distorted representation of the sources of cyclicalfluctuations, of the transmission of shocks and of the events of the last 40 years.

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Agent-based computational economics is becoming widely used in practice. This paperexplores the consistency of some of its standard techniques. We focus in particular on prevailingwholesale electricity trading simulation methods. We include different supply and demandrepresentations and propose the Experience-Weighted Attractions method to include severalbehavioural algorithms. We compare the results across assumptions and to economic theorypredictions. The match is good under best-response and reinforcement learning but not underfictitious play. The simulations perform well under flat and upward-slopping supply bidding,and also for plausible demand elasticity assumptions. Learning is influenced by the number ofbids per plant and the initial conditions. The overall conclusion is that agent-based simulationassumptions are far from innocuous. We link their performance to underlying features, andidentify those that are better suited to model wholesale electricity markets.

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We investigate the impact of 20th--century European colonizationon growth in Africa. We find that in the 1960--88 period growth has beenfaster for dependencies than for colonies; for British and Frenchcolonies than for Portuguese, Belgian and Italian ones; and for countrieswith less economic penetration during the colonial period. On average,African growth accelerates after decolonization. Proxies for colonialheritage add explanatory power to growth regressions and make indicatorsfor human capital, political and ethnic instability lose significance.Colonial variables capture the same effects of a sub--Saharan dummy andreduce its significance when jointly included in a cross sectionalregression with 98 countries.

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We examine the role of expectations in the Great Moderation episode. We derive theoretical restrictions in a New-Keynesian model and test them using measures of expectations obtained from survey data, the Greenbook and bond markets. Expectations explain the dynamics of inflation and of interest rates but their importance is roughly unchanged over time. Systems with and without expectations display similar reduced form characteristics. Including or excluding expectations hardly changes the economic explanation of the Great Moderation. Results are robust to changes in the structure of the empirical model.

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[spa] La conceptuación de talento ha ido cobrando cada vez más importancia tanto para académicos como profesionales, con el fin de avanzar en el estudio de la gestión del talento. De hecho, la confusión sobre el significado de talento en la realidad empresarial impide llegar a un consenso sobre el concepto y la práctica de la gestión del talento. En este estudio teórico revisamos el concepto de talento en el mundo de la empresa con el fin de resumir lo que hemos aprendido y discutir las ventajas y limitaciones de las diferentes acepciones. Concluimos con la formulación de una definición de este concepto, ya que una correcta interpretación de la gestión del talento—por no hablar de una exitosa gestión del talento— depende de tener una comprensión clara de lo que se entiende por talento en un contexto organizativo. Además, con la definición de talento propuesta delimitamos el concepto de talento evitando algunos problemas detectados en las definiciones anteriores (por ejemplo, generalidades y tautologías), y poniendo de relieve las variables importantes que le afectan y lo hacen más manejable.

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he complex refractive index of SiO2 layers containing Si nanoclusters (Si-nc) has been measured by spectroscopic ellipsometry in the range from 1.5 to 5.0 eV. It has been correlated with the amount of Si excess accurately measured by x-ray photoelectron spectroscopy and the nanocluster size determined by energy-filtered transmission electron microscopy. The Si-nc embedded in SiO2 have been produced by a fourfold Si+ ion implantation, providing uniform Si excess aimed at a reliable ellipsometric modeling. The complex refractive index of the Si-nc phase has been calculated by the application of the Bruggeman effective-medium approximation to the composite media. The characteristic resonances of the refractive index and extinction coefficient of bulk Si vanish out in Si-nc. In agreement with theoretical simulations, a significant reduction of the refractive index of Si-nc is observed, in comparison with bulk and amorphous silicon. The knowledge of the optical properties of these composite layers is crucial for the realization of Si-based waveguides and light-emitting devices.

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In the present work, an analysis of the dark and optical capacitance transients obtained from Schottky Au:GaAs barriers implanted with boron has been carried out by means of the isothermal transient spectroscopy (ITS) and differential and optical ITS techniques. Unlike deep level transient spectroscopy, the use of these techniques allows one to easily distinguish contributions to the transients different from those of the usual deep trap emission kinetics. The results obtained show the artificial creation of the EL2, EL6, and EL5 defects by the boron implantation process. Moreover, the interaction mechanism between the EL2 and other defects, which gives rise to the U band, has been analyzed. The existence of a reorganization process of the defects involved has been observed, which prevents the interaction as the temperature increases. The activation energy of this process has been found to be dependent on the temperature of the annealing treatment after implantation, with values of 0.51 and 0.26 eV for the as‐implanted and 400 °C annealed samples, respectively. The analysis of the optical data has corroborated the existence of such interactions involving all the observed defects that affect their optical parameters

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[spa] La conceptuación de talento ha ido cobrando cada vez más importancia tanto para académicos como profesionales, con el fin de avanzar en el estudio de la gestión del talento. De hecho, la confusión sobre el significado de talento en la realidad empresarial impide llegar a un consenso sobre el concepto y la práctica de la gestión del talento. En este estudio teórico revisamos el concepto de talento en el mundo de la empresa con el fin de resumir lo que hemos aprendido y discutir las ventajas y limitaciones de las diferentes acepciones. Concluimos con la formulación de una definición de este concepto, ya que una correcta interpretación de la gestión del talento—por no hablar de una exitosa gestión del talento— depende de tener una comprensión clara de lo que se entiende por talento en un contexto organizativo. Además, con la definición de talento propuesta delimitamos el concepto de talento evitando algunos problemas detectados en las definiciones anteriores (por ejemplo, generalidades y tautologías), y poniendo de relieve las variables importantes que le afectan y lo hacen más manejable.