Existence Results for Quasilinear Degenerated Equations Via Strong Convergence of Truncations

In this paper we study the existence of solutions for quasilinear degenerated elliptic operators A(u) + g(x, u,ru) = f , where A is a Leray-Lions operator from W1,pIn this paper we study the existence of solutions for quasilinear degenerated elliptic operators A(u) + g (x, u, u) = f , where A is a Leray-Lions operator from W0 ,p (, w) into its dual, while g (x, s, ) is a nonlinear term which has 1 a growth condition with respect to and no growth with respect to s, but it satisfies a sign condition on s. The right hand side f is assumed to belong either to W -1,p (, w ) or to L1 ()

Theoretical Study of Physisorption of Nucleobases on Boron Nitride Nanotubes: A New Class of Hybrid Nano-Bio Materials

We investigate the adsorption of the nucleic acid bases, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U) on the outer wall of a high curvature semiconducting single-walled boron nitride nanotube (BNNT) by first principles density functional theory calculations. The calculated binding energy shows the order: G>A\approxC\approxT\approxU implying that the interaction strength of the (high-curvature) BNNT with the nucleobases, G being an exception, is nearly the same. A higher binding energy for the G-BNNT conjugate appears to result from a stronger hybridization of the molecular orbitals of G and BNNT, since the charge transfer involved in the physisorption process is insignificant. A smaller energy gap predicted for the G-BNNT conjugate relative to that of the pristine BNNT may be useful in application of this class of biofunctional materials to the design of the next generation sensing devices.Comment: 17 pages 6 figure

Land-use change and sustainability in the south-eastern oases of Morocco

The study apprehends modern versus traditional land-use changes in the Moroccan oases. The traditional local knowledge and land-use that ensured ecological equilibrium for centuries is decreasing. Modern entrepreneuship practices are increasing and have risky environmental impacts. By using the spatial and factor analyses, we confirm the spatial disparities in the region and distinguish four different groups of communes (in high mountain communes, traditional agriculture favors resources’ conservation; downstream communes experience greater changes and ecological ruptures). The recommendations of the study include the need to rethink adopted development models and elaborate new actions that respect local specificities, consider environmental equilibrium and rehabilitate local ecosystems

Fokker-Planck Equation for Boltzmann-type and Active Particles: transfer probability approach

Fokker-Planck equation with the velocity-dependent coefficients is considered for various isotropic systems on the basis of probability transition (PT) approach. This method provides the self-consistent and universal description of friction and diffusion for Brownian particles. Renormalization of the friction coefficient is shown to occur for two dimensional (2-D) and three dimensional (3-D) cases, due to the tensorial character of diffusion. The specific forms of PT are calculated for the Boltzmann-type of collisions and for the absorption-type of collisions (the later are typical for dusty plasmas and some other systems). Validity of the Einstein's relation for the Boltzmann-type collisions is analyzed for the velocity-dependent friction and diffusion coefficients. For the Boltzmann-type collisions in the region of very high grain velocity as well as it is always for non-Boltzmann collisions, such as, e.g., absorption collisions, the Einstein relation is violated, although some other relations (determined by the structure of PT) can exist. The generalized friction force is investigated in dusty plasma in the framework of the PT approach. The relation between this force, negative collecting friction force and scattering and collecting drag forces is established.+AFwAXA- The concept of probability transition is used to describe motion of active particles in an ambient medium. On basis of the physical arguments the PT for a simple model of the active particle is constructed and the coefficients of the relevant Fokker-Planck equation are found. The stationary solution of this equation is typical for the simplest self-organized molecular machines.+AFwAXA- PACS number(s): 52.27.Lw, 52.20.Hv, 52.25.Fi, 82.70.-yComment: 18 page

Las controversias de los actores y la gobernanza territorial en las cercanías del sur de Fez (Marruecos)

This article discusses the actors’ controversies on the suburban development in the southern vicinity of Fez (the commune of Ain Chkef, Morocco). These controversies are heavily affecting the local development and impose costly burdens in terms of impacts on local systems. They were analyzed in this article using a synthetic spatial methodology based on socio-spatial data and cartography by ArcGis. The role of terrestrial property on actors’ intense controversies in the area is discussed in terms of the opportunities it offers for investment and as conflicts’ factor between rights’ holders, operators and other developing actors. Controversies are sometimes linked to issues of land value, the development of activities (gentrification, activity zones and actors contesting positions), and to the location of major equipment or environmental resources. The governance and steering of local development under these conditions is complex, because the decision-maker should assimilate the actors’ needs and all influencing parameters in the suburbs, to develop the convergent governance suggested as a solution. It includes clear visions, a further knowledge of territorial stakes, the key factors of the territorial management and the causes and motivations of the actors’ controversies to find adapted solutions and answers to their questions. Convergent governance must be anticipative, communicative and able to create the actors’ convergences. Suburbs’ complex realities may therefore be best understood using the convergent governance approach with a further consideration of relationality and territoriality that integrate the local, regional and external contextual influencing factors.Este artículo analiza las controversias de los actores sobre el desarrollo suburbano en las cercanías del sur de Fez (la comuna de Ain Chkef, Marruecos). Estas controversias están afectando en gran medida el desarrollo local e imponen cargas costosas en términos de impactos en los sistemas locales. Se analizan en este artículo estas controversias utilizando una metodología espacial sintética basada en datos socio-espaciales y cartografía de ArcGis. El papel de la propiedad de la tierra en las intensas controversias de los actores en el área se discute en términos de las oportunidades que ofrece para la inversión y como un factor de conflicto entre los titulares de derechos, operadores y otros actores en desarrollo. Las controversias a veces están vinculadas a cuestiones relacionadas con el valor de la tierra, el desarrollo de actividades (gentrificación, zonas de actividad y actores que disputan puestos), y a la ubicación de equipos principales o recursos ambientales. La gobernanza y la dirección del desarrollo local en estas condiciones es compleja, ya que el tomador de decisiones debe asimilar las necesidades de los actores y todos los parámetros que influyen en los suburbios, para desarrollar la gobernanza convergente sugerida como una solución. Incluye visiones claras, un mayor conocimiento de los intereses territoriales, los factores clave de la gestión territorial y las causas y motivaciones de las controversias de los actores para encontrar soluciones y respuestas adaptadas a sus preguntas. La gobernanza convergente debe ser anticipativa, comunicativa y capaz de crear las convergencias de los actores. Por lo tanto, las realidades complejas de los suburbios pueden entenderse mejor utilizando el enfoque de gobernanza convergente con una consideración adicional de la relación y la territorialidad que integran los factores de influencia contextuales locales, regionales y externos

Structure and Phase transitions of Yukawa balls

In this review, an overview of structural properties and phase transitions in finite spherical dusty (complex) plasma crystals -- so-called Yukawa balls -- is given. These novel kinds of Wigner crystals can be directly analyzed experimentally with video cameras. The experiments clearly reveal a shell structure and allow to determine the shell populations, to observe metastable states and transitions between configurations as well as phase transitions. The experimental observations of the static properties are well explained by a rather simple theoretical model which treats the dust particles as being confined by a parabolic potential and interacting via an isotropic Yukawa pair potential. The excitation properties of the Yukawa balls such as normal modes and the dynamic behavior, including the time-dependent formation of the crystal requires, in addition, to include the effect of friction between the dust particles and the neutral gas. Aside from first-principle molecular dynamics and Monte Carlo simulations several analytical approaches are reviewed which include shell models and a continuum theory. A summary of recent results and theory-experiment comparisons is given and questions for future research activities are outlined.Comment: Invited review, submitted to Contrib. Plasmas Physic

The influence of eWOM. Analyzing its characteristics and consequences, and future research linesLa influencia de eWOM. Analizando sus caracteristicas, consecuencas y futuras lineas de investigación

Purpose: This study, first, reviews the existing literature on electronic word-of-mouth (eWOM) and, using communication theory, examines its impact on its readers’ decision-making processes. Second, this paper aims to propose some elements of eWOM communications that might be further researched. Design/methodology/approach: A literature review of relevant academic articles produced 97 works related to social communication theory, eWOM and new artificial intelligence trends in hospitality. Thereafter, potential avenues for future research were explored. Findings: The study results showed: valence, relevance, understandability and visual cues are the most important antecedents of message usefulness and the reader’s behavioral intentions; source credibility is the sender characteristic that most affects the reader’s behavioral intentions and consumer susceptibility to interpersonal influence is the receiver characteristic that most influences their attitudes and behavioral intentions. In addition, the study highlights four relevant aspects for future research. First, more research into online fake reviews is needed to better understand sender motivations. Second, companies should actively manage negative reviews. Then, the careful choice of platforms on which companies promote their products/services. Finally, the role of artificial intelligence in increasing the effectiveness of eWOM in the hospitality industry. Originality/value: This paper integrates – grounded on communication theory – results from previous studies about the central elements of communication (message, sender and receiver) and discusses the main trends in hospitality-related eWOM. In addition, the paper examines the potential of specific eWOM elements as future lines of research, in particular: fake reviews, strategies for dealing with negative reviews, the eWOM platform used and artificial intelligence applications

Perceived value of AI-based recommendations¿ service: the case of voice assistants

The application of artificial intelligence in services is continuously spreading. In particular, one of the most important recent trends is the development of virtual assistants, more particularly; voice assistants, which provide consumers with various services (e.g. information, music) and with product and service recommendations based on their preferences. There is a need to understand how valuable these recommendations are for consumers. This study contributes to the emerging body of research into consumers’ use of the recommendations that voice assistants make in three key ways: (1) by analysing the roles of the benefits (i.e. convenience, compatibility, personalisation) they derive and costs they expend (i.e. cognitive effort, intrusiveness) in the value creation process related to voice assistants’ recommendations; (2) by evaluating the effect of social presence (the key voice assistant feature) on perceived value of voice assistants’ recommendations, through the benefits and costs associated with voice assistants and (3) by determining how the perceived value of voice assistants’ recommendations affects consumer engagement. An online survey was used to collect data. Partial least squares structural equation modelling (PLS-SEM) was employed to analyse the conceptual model. The core findings of the study are as follows. First, social presence enhances the benefits (especially personalisation) and reduces the costs (except for cognitive effort) associated with voice assistants. Second, personalisation was shown to be the strongest determinant of the perceived value of voice assistants’ recommendations, but their intrusiveness is a potential inhibitor in the way of increasing their value. Third, a positive relationship was observed between the perceived value of voice assistants’ recommendations and consumer engagement with the assistants

Scale’s impact in education system’s performance: Cases in Draa-Tafilalet, Morocco

This study aimed to apprehend the scale’s role in education planning and performance. The national scale approaches tend to neglect local specificities. The relevance of the provincial and local scales is underlined in Draa-Tafilalet region (Morocco). By comparing the provincial data and indicators to study the education system's efficiency, we argue that these are pertinent scales to further understanding the needs, causality and key parameters of education. Collected data is analyzed using the data envelopment analysis (DEA). Useful indicators to compare the spatial variability of the education system’s efficiency were produced and discussed at a provincial scale and interpreted considering the local socioeconomic characteristics in each province. The five provinces of the region (Errachidia, Ouarzazate, Tineghir, Midelt, Zagora, and Midelt) are considered as adapted decision-making unit (DMU) in the study. The results show the provincial scale is relevant to apprehend the education system’s performance. It is also important in education planning. The spatial differences in education efficiency at this scale show evidence of weak education impacts among rural populations in the recently created provinces such as Tineghir, Midelt, and Zagora. The criterion of education efficiency measured by DEA ranks Tineghir in the last position. This province needs special attention in planning and development