Potential isomorphism of elementary substructures of a strictly stable homogeneous model

"Vegeu el resum a l'inici del document del fitxer adjunt."

Predicting the potential for lightning activity in mediterranean storms based on the WRF model dynamic and microphysical fields

A new parameter is introduced: the lightning potential index (LPI), which is a measure of the potential for charge generation and separation that leads to lightning flashes in convective thunderstorms. The LPI is calculated within the charge separation region of clouds between 0 C and 20 C, where the noninductive mechanism involving collisions of ice and graupel particles in the presence of supercooled water is most effective. As shown in several case studies using the Weather Research and Forecasting (WRF) model with explicit microphysics, the LPI is highly correlated with observed lightning. It is suggested that the LPI may be a useful parameter for predicting lightning as well as a tool for improving weather forecasting of convective storms and heavy rainfall.

Comment on the plasmon model for image-potential-induced surface states

Calculations of the binding energy of bound positron states in metal surfaces, with explicit inclusion of plasmon dispersion and single-particle effects, are presented. The binding energy is greatly reduced with respect to the undispersed case.

Optical-model potential for electron and positron elastic scattering by atoms

An optical-model potential for systematic calculations of elastic scattering of electrons and positrons by atoms and positive ions is proposed. The electrostatic interaction is determined from the Dirac-Hartree-Fock self-consistent atomic electron density. In the case of electron projectiles, the exchange interaction is described by means of the local-approximation of Furness and McCarthy. The correlation-polarization potential is obtained by combining the correlation potential derived from the local density approximation with a long-range polarization interaction, which is represented by means of a Buckingham potential with an empirical energy-dependent cutoff parameter. The absorption potential is obtained from the local-density approximation, using the Born-Ochkur approximation and the Lindhard dielectric function to describe the binary collisions with a free-electron gas. The strength of the absorption potential is adjusted by means of an empirical parameter, which has been determined by fitting available absolute elastic differential cross-section data for noble gases and mercury. The Dirac partial-wave analysis with this optical-model potential provides a realistic description of elastic scattering of electrons and positrons with energies in the range from ~100 eV up to ~5 keV. At higher energies, correlation-polarization and absorption corrections are small and the usual static-exchange approximation is sufficiently accurate for most practical purposes.

Model-independent bounds for the potential and kinetic energy of liquid 4He at zero temperature

Using the experimental values of the chemical potentials of liquid 4He and of a 3He impurity in liquid 4He, we derive a model-independent lower (upper) bound to the kinetic (potential) energy per particle at zero temperature. The values of the bounds at the experimental saturation density are 13.42 K for the kinetic energy and -20.59 K for the potential energy. All the theoretical calculations based on the Lennard-Jones potential violate the upper-bound condition for the potential energy.

Synthesis of the two isomers of the potential sex pheromone of Thaumetopoea pityocampa (Lepidoptera, Notodontidae) and related model compounds

The synthesis of the major component of the sex pheromone secretion of the processionary moth, Tkawnztopoeja pltyocampa (Denis and Schiff.) (Lepidoptera, Notodontidae), (Z)-13-hexadecen-ll-ynyl acetate (1), the corresponding (E)-isomer (2) and the four structurally related model compounds (Z⁄E,Z,Z)-5,9,13-hexadecatrienyl acetate (3), (Z⁄E,Z,Z)-3,7,ll-hexadecatrienyl acetate (4), (Z⁄E,E,Z)-7,9,13-hexadecatrienyl acetate (5) and (Z)-7-hexadecen-5-ynyl acetate (6) is described.

Knowledge of Catalan, public/private sector choice and earnings: Evidence from a double sample selection model

This paper explores the earnings return to Catalan knowledge for public and private workers in Catalonia. In doing so, we allow for a double simultaneous selection process. We consider, on the one hand, the non-random allocation of workers into one sector or another, and on the other, the potential self-selection into Catalan proficiency. In addition, when correcting the earnings equations, we take into account the correlation between the two selectivity rules. Our findings suggest that the apparent higher language return for public sector workers is entirely accounted for by selection effects, whereas knowledge of Catalan has a significant positive return in the private sector, which is somewhat higher when the selection processes are taken into account.

Bringing actors and violent conflict into forced migration literature. A model of the decision to return

Populations displaced as a result of mass violent conflict have become one of the most pressing humanitarian concerns of the last decades. They have also become one salient political issue as a perceived burden (in economic and security terms) and as an important piece in the shift towards a more interventionist paradigm in the international system, based on both humanitarian and security grounds. The saliency of these aspects has detracted attention from the analysis of the interactions between relocation processes and violent conflict. Violent conflict studies have also largely ignored those interactions as a result of the consideration of these processes as mere reaction movements determined by structural conditions. This article takes the view that individual’s agency is retained during such processes, and that it is consequential, calling for the need to introduce a micro perspective. Based on this, a model for the individual’s decision of return is presented. The model has the potential to account for the dynamics of return at both the individual and the aggregate level. And it further helps to grasp fundamental interconnections with violent conflict. Some relevant conclusions are derived for the case of Bosnia-Herzegovina and about the implications of the politicization of return.

A cognitive attempt to understanding female entrepreneurial potential: the role of social norms and culture

This article analyzes the different perceptions of both male and female potential entrepreneurs from three European regions differing in their respective level of economic development and entrepreneurial culture. We use an extended cognitive model of entrepreneurial intentions based on the theory of planned behaviour, the theory of normative social behaviour and social capital literature. Results show females have lower self-efficacy and entrepreneurial attraction than males, thus leading to lower entrepreneurial intention. Differences between the three subsamples are small when males are studied. However, female entrepreneurial intentions and perceptions are more affected by the cultural context.

Nuclear magnetic resonance chemical shifts with the statistical average of orbital-dependent model potentials in Kohn-Sham density functional theory

The performance of the SAOP potential for the calculation of NMR chemical shifts was evaluated. SAOP results show considerable improvement with respect to previous potentials, like VWN or BP86, at least for the carbon, nitrogen, oxygen, and fluorine chemical shifts. Furthermore, a few NMR calculations carried out on third period atoms (S, P, and Cl) improved when using the SAOP potential

Excuse me, but your accent is very unusual. The complexity of establishing third languages in Inglourious Basterds. Applying a model of translation analysis to dubbing

The growing multilingual trend in movie production comes with a challenge for dubbing translators since they are increasingly confronted with more than one source language. The main purpose of this master’s thesis is to provide a case study on how these third languages (see CORRIUS and ZABALBEASCOA 2011) are rendered. Another aim is to put a particular focus on their textual and narrative functions and detect possible shifts that might occur in translations. By applying a theoretical model for translation analysis (CORRIUS and ZABALBEASCOA 2011), this study describes how third languages are rendered in the German, Spanish, and Italian dubbed versions of the 2009 Tarantino movie Inglourious Basterds. A broad range of solution-types are thereby revealed and prevalent restrictions of the translation process identified. The target texts are brought in context with some sociohistorical aspects of dubbing in order to detect prevalent norms of the respective cultures andto discuss the acceptability of translations (TOURY 1995). The translatability potential of even highly complex multilingual audiovisual texts is demonstrated in this study. Moreover, proposals for further studies in multilingual audiovisual translation are outlined and the potential for future investigations in this field thereby emphasised.

An agenda-setting model of electoral competition

This paper presents a model of electoral competition focusing on the formation of thepublic agenda. An incumbent government and a challenger party in opposition competein elections by choosing the issues that will key out their campaigns. Giving salience toan issue implies proposing an innovative policy proposal, alternative to the status-quo.Parties trade off the issues with high salience in voters concerns and those with broadagreement on some alternative policy proposal. Each party expects a higher probabilityof victory if the issue it chooses becomes salient in the voters decision. But remarkably,the issues which are considered the most important ones by a majority of votes may notbe given salience during the electoral campaign. An incumbent government may survivein spite of its bad policy performance if there is no sufficiently broad agreement on apolicy alternative. We illustrate the analytical potential of the model with the case of theUnited States presidential election in 2004.

A house price index defined in the potential outcomes framework

Current methods for constructing house price indices are based on comparisons of sale prices of residential properties sold two or more times and on regression of the sale prices on the attributes of the properties and of their locations. The two methods have well recognised deficiencies, selection bias and model assumptions, respectively. We introduce a new method based on propensity score matching. The average house prices for two periods are compared by selecting pairs of properties, one sold in each period, that are as similar on a set of available attributes (covariates) as is feasible to arrange. The uncertainty associated with such matching is addressed by multiple imputation, framing the problem as involving missing values. The method is applied to aregister of transactions ofresidential properties in New Zealand and compared with the established alternatives.

A model of market-making

The two essential features of a decentralized economy taken intoaccount are, first, that individual agents need some informationabout other agents in order to meet potential trading partners,which requires some communication or interaction between theseagents, and second, that in general agents will face tradinguncertainty. We consider trade in a homogeneous commodity. Firmsdecide upon their effective supplies, and may create their ownmarkets by sending information signals communicating theirwillingness to sell. Meeting of potential trading partners isarranged in the form of shopping by consumers. The questions to beconsidered are: How do firms compete in such markets? And what arethe properties of an equilibrium? We establish existenceconditions for a symmetric Nash equilibrium in the firms'strategies, and analyze its characteristics. The developedframework appears to lend itself well to study many typicalphenomena of decentralized economies, such as the emergence ofcentral markets, the role of middlemen, and price-making.

Market structure and hospital efficiency: Evaluating potential effects of deregulation in a national health service

In this article we examine the potential effect of market structureon hospital technical efficiency as a measure of performance controlled byownership and regulation. This study is relevant to provide an evaluationof the potential effects of recommended and initiated deregulation policiesin order to promote market reforms in the context of a European NationalHealth Service. Our goal was reached through three main empirical stages.Firstly, using patient origin data from hospitals in the region of Cataloniain 1990, we estimated geographic hospital markets through the Elzinga--Hogartyapproach, based on patient flows. Then we measured the market level ofconcentration using the Herfindahl--Hirschman index. Secondly, technicaland scale efficiency scores for each hospital was obtained specifying aData Envelopment Analysis. According to the data nearly two--thirds of thehospitals operate under the production frontier with an average efficiencyscore of 0.841. Finally, the determinants of the efficiency scores wereinvestigated using a censored regression model. Special attention waspaid to test the hypothesis that there is an efficiency improvement in morecompetitive markets. The results suggest that the number of competitors inthe market contributes positively to technical efficiency and there is someevidence that the differences in efficiency scores are attributed toseveral environmental factors such as ownership, market structure andregulation effects.