An isoperimetric-type inequality for electrostatic shell interactions for Dirac operators

In this article we investigate spectral properties of the coupling $H+V_\lambda$, where $H=-i\alpha\cdot\nabla +m\beta$ is the free Dirac operator in $\mathbb R^3$, $m>0$ and $V_\lambda$ is an electrostatic shell potential (which depends on a parameter $\lambda\in\mathbb R$) located on the boundary of a smooth domain in $\mathbb R^3$. Our main result is an isoperimetric-type inequality for the admissible range of $\lambda$'s for which the coupling $H+V_\lambda$ generates pure point spectrum in $(-m,m)$. That the ball is the unique optimizer of this inequality is also shown. Regarding some ingredients of the proof, we make use of the Birman-Schwinger principle adapted to our setting in order to prove some monotonicity property of the admissible $\lambda$'s, and we use this to relate the endpoints of the admissible range of $\lambda$'s to the sharp constant of a quadratic form inequality, from which the isoperimetric-type inequality is derived.Comment: 21 page

STOCHASTIC CHOICE ANALYSIS OF TOURISM DESTINATIONS

The analysis of tourist destination choice, defined by intra-country administrative units and by product types "coastal/inland and village/city", permits the characterisation of tourist flow behaviour, which is fundamental for public planning and business management. In this study, we analyse the determinant factors of tourist destination choice, proposing various research hypotheses relative to the impact of destination attributes and the personal characteristics of tourists. The methodology applied estimates Nested and Random Coefficients Multinomial Logit Models, which allow control over possible correlations among different destinations. The empirical application is realised in Spain on a sample of 3,781 individuals and allows us to conclude that prices, distance to the destination and personal motivations are determinants in destination choice.Tourism Marketing, Intra-country destination, Coastal/inland, Village/city, Nested and Random Coefficients Logit Models.

ANALYSING THREE BASIC DECISIONS OF TOURISTS: GOING AWAY, GOING ABROAD AND GOING ON TOUR

This study analyses determinant factors in the taking of three basic decisions on the part of holidaymakers: going on holiday, foreign holidays and multi-destination holidays. We propose various research hypotheses relating to the impact on these decisions of various personal characteristics. The methodology used estimates various Binomial Logit models. The empirical application carried out in Spain on a sample of 3,781 individuals allows us to conclude that personal characteristics related to the chosen destination, personal restrictions and socio-demographic and psychographic characteristics are determinants of these decisions. This study analyses determinant factors in the taking of three basic decisions onthe part of holidaymakers: going on holiday, foreign holidays and multi-destinationholidays. We propose various research hypotheses relating to the impact on thesedecisions of various personal characteristics. The methodology used estimates variousBinomial Logit models. The empirical application carried out in Spain on a sample of3,781 individuals allows us to conclude that personal characteristics related to thechosen destination, personal restrictions and socio-demographic and psychographiccharacteristics are determinants of these decisions.Tourism Marketing, Choice Behaviour, Probabilistic Choice Models Marketing Turístico, Comportamiento de Elección, Modelos Probabilísticos de Elección.

HECKIT MODELLING OF THE TWO-STAGE TOURIST CHOICE PROCESS: GOING ON HOLIDAY AND TOURISM EXPENDITURES

The objective of this paper is to decompose the process of tourist choice into two stages: taking a holiday and tourism expenditures, using the Heckit model, which avoids the problems of the methodologies applied to date. We propose hypotheses on the effect on the above decisions of tourist characteristics relating to the destination, personal restrictions and socio-demographic and psychographic characteristics. The empirical application, which is carried out in Spain on a sample of 3,781 individuals, finds a two-stage tourist choice process as the expenditure decision is correlated with that of taking a holiday. In addition, these decisions are also explained by individual tourist characteristics. El objetivo de esta investigación consiste descomponer el proceso de elecciónturístico en dos etapas, salir de vacaciones y gasto turístico, utilizando la modelizaciónHeckit que evita los problemas de las metodologías aplicadas hasta la fecha. Para ello,se proponen hipótesis de investigación acerca del efecto en las decisiones anteriores delas características de los turistas relacionadas con el destino, las restriccionespersonales, las características socio-demográficas y psicográficas. La aplicaciónempírica, efectuada en España sobre una muestra de 3.781 individuos, evidencia unproceso de elección turística bietápico ya que la decisión de gasto está correlacionadacon la de salir de vacaciones. Además, estas decisiones vienen explicadas por lascaracterísticas individuales del turista.Proceso de elección turística bietápica, salir de vacaciones, gastos en turismo, modelo Heckit. Two-stage tourist choice process, going on holiday, tourism expenditures, Heckit model.

The negative effects of failed service recoveries

Research has shown that more than half of attempted recovery efforts fail, producing a "double deviation" effect. Surprisingly, these double deviation effects have received little attention in marketing literature. This paper examines what happens after these critical encounters, which behavior or set of behaviors the customers are prone to follow and how customers' perceptions of the firm's recovery efforts influence these behaviors. For the analysis of choice of the type of response (complaining, exit, complaining and exit, and no-switching), we estimate multinomial Logit models with random coefficients (RCL). The results of our study show that magnitude of service failure, explanations, apologies, perceived justice, angry and frustration felt by the customer, and satisfaction with service recovery have a significant effect on customers' choice of the type of response. Implications from the findings are offered. La investigación ha mostrado que más de la mitad de los intentos de recuperación tras el fallo de un servicio fracasan, lo que produce un efecto de "desviación doble". Sorprendentemente, estos efectos de desviación doble han recibido muy poca atención en la literatura de marketing. Este trabajo analiza qué ocurre tras estos encuentros críticos, ¿qué comportamiento o conjunto de comportamientos tienden a seguir lo clientes? y ¿cómo afectan a estos comportamientos las percepciones de los clientes acerca del problema y de los esfuerzos de recuperación de la empresa?. Para el análisis del tipo de respuesta (queja, abandono, queja y abandono, y no cambiar de entidad), estimamos modelos Logit multinomiales con coeficientes aleatorios (RCL). Los resultados de nuestro estudio muestran que la magnitud del fallo inicial, las explicaciones y disculpas recibidas tras el mismo, la justicia percibida en la gestión de la queja, la frustración y el enfado que siente el cliente y la satisfacción con el proceso de recuperación, tienen un efecto significativo en la elección de los clientes del tipo de respuesta de queja. Finalmente, se ofrecen implicaciones para la gestión.desviación doble, comportamiento de queja del consumidor, modelos Logit multinomiales con coeficientes aleatorios (RCL), recuperación del servicio. Double deviations, consumer complaining behavior (CCB), multinomial logit models with random coefficients (RCL), service recovery.

Detecting Free Riders in Collective Brands through a Hierarchical Choice Process

Free-riding behaviors exist in tourism and they should be analyzed from a comprehensive perspective; while the literature has mainly focused on free riders operating in a destination, the destinations themselves might also free ride when they are under the umbrella of a collective brand. The objective of this article is to detect potential free-riding destinations by estimating the contribution of the different individual destinations to their collective brands, from the point of view of consumer perception. We argue that these individual contributions can be better understood by reflecting the various stages that tourists follow to reach their final decision. A hierarchical choice process is proposed in which the following choices are nested (not independent): “whether to buy,” “what collective brand to buy,” and “what individual brand to buy.” A Mixed Logit model confirms this sequence, which permits estimation of individual contributions and detection of free riders

Papel moderador de las motivaciones en el efecto de los precios de los destinos turísticos

La literatura de elección de destinos turísticos ha dedicado una gran atención al impacto directo del atributo “precio del destino”, pero no ha alcanzado un consenso en torno al mismo. Alternativamente, nuestro trabajo toma como punto de partida la relación entre las motivaciones turísticas y los beneficios buscados del turista en un destino, lo que lleva a proponer que el efecto del precio viene moderado por las motivaciones del turista a la hora de elegir un destino. Para ello, se argumentan diversas hipótesis de investigación que explican esta decisión a través de la interacción entre dicho atributo del destino y las motivaciones personales de los individuos. La metodología aplicada estima Modelos Logit con Coeficientes Aleatorios que permiten controlar posibles correlaciones entre los distintos destinos y recoger la heterogeneidad de los turistas. La aplicación empírica realizada en España sobre una muestra de 2.127 individuos evidencia que las motivaciones moderan el efecto de los precios en la elección de los destinos turísticos intrapaís.The literature of tourist destination choice pays great attention to the direct impact of the prices of the destination, but does not reach any consensus around them. Alternatively, our study takes as a starting point the relationships between tourist motivations and expected benefits. This allows us to propose that the effect of prices are moderated by tourist motivations at the moment of choosing a destination, which leads us to make hypotheses to explain this decision through the interaction between this destination attribute and the personal motivations of the individual tourists. The methodology applied estimates Random Coefficient Logit models, which control possible correlations between different destinations and considers tourist heterogeneity. The empirical application carried out in Spain on a sample of 2,127 individuals, shows that motivations moderate the effects of prices on the choice of tourist destination.Este trabajo se ha beneficiado de una beca “Turismo de España” de la Secretaría de Estado de Comercio y Turismo del Ministerio de Economía para la realización de Tesis Doctorales de la que el primer autor ha sido adjudicatario

Elección temporal de los viajes turísticos: una aproximación con modelos de recuento

Comunicación presentada en el XIII Congreso Nacional de ACEDE, Salamanca, 21-23 septiembre 2003.El presente trabajo analiza los factores determinantes de la elección temporal de los viajes turísticos. Para ello, se proponen varias hipótesis que explican la decisión del número de días que los individuos van a salir de vacaciones fuera del lugar de residencia habitual en términos de restricciones personales y características personales. La metodología aplicada estima, como novedad en este tipo de decisiones, un Modelo Binomial Negativo Truncado que evita los sesgos de estimación de los modelos de regresión y los supuestos restrictivos de los Modelos de Poisson. La aplicación empírica realizada en España sobre una muestra de 3.781 individuos permite concluir que las restricciones temporales y el tamaño de la ciudad de residencia son determinantes de la decisión temporal de la duración de la estancia. Asimismo, se ha detectado la existencia de heterogeneidad en las preferencias de los turistas, mediante el contraste del supuesto de igualdad media-varianza, lo que evidencia que el Modelo Binomial Negativo es más adecuado que el de Poisson para realizar este tipo de análisis.Este trabajo se ha beneficiado de una beca “Turismo de España” de la Secretaría de Estado de Comercio y Turismo del Ministerio de Economía para la realización de Tesis Doctorales de la que el primer autor ha sido adjudicatario

Detection of a Super Star Cluster as the Ionizing Source in the Low Luminosity AGN NGC 4303

HST UV STIS imaging and spectroscopy of the low luminosity AGN (LLAGN) NGC 4303 have identified the previously detected UV-bright nucleus of this galaxy, as a compact, massive and luminous stellar cluster. The cluster with a size (FWHM) of 3.1 pc, and an ultraviolet luminosity log L (1500 A}(erg/s/A)= 38.33 is identified as a nuclear super star cluster (SSC) like those detected in the circumnuclear regions of spirals and starburst galaxies. The UV spectrum showing the characteristic broad P Cygni lines produced by the winds of massive young stars, is best fitted by the spectral energy distribution of a massive cluster of 1e5 Msol generated in an instantaneous burst 4 Myr ago. No evidence for an additional non-thermal ionizing source associated with an accreting black hole is detected in the ultraviolet. We hypothesize that at least some LLAGNs in spirals could be understood as the result of the combined ionizing radiation emitted by an evolving SSC and a black hole (BH) accreting with low radiative efficiency, coexisting in the inner few parsecs region.Comment: 4 figure