342 research outputs found

    Casimir effect in a wormhole spacetime

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    We consider the Casimir effect for quantized massive scalar field with non-conformal coupling Îľ\xi in a spacetime of wormhole whose throat is rounded by a spherical shell. In the framework of zeta-regularization approach we calculate a zero point energy of scalar field. We found that depending on values of coupling Îľ\xi, a mass of field mm, and/or the throat's radius aa the Casimir force may be both attractive and repulsive, and even equals to zero.Comment: 2 figures, 10 pages, added 2 reference

    Local and Global Casimir Energies for a Semitransparent Cylindrical Shell

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    The local Casimir energy density and the global Casimir energy for a massless scalar field associated with a λδ\lambda\delta-function potential in a 3+1 dimensional circular cylindrical geometry are considered. The global energy is examined for both weak and strong coupling, the latter being the well-studied Dirichlet cylinder case. For weak-coupling,through O(λ2)\mathcal{O}(\lambda^2), the total energy is shown to vanish by both analytic and numerical arguments, based both on Green's-function and zeta-function techniques. Divergences occurring in the calculation are shown to be absorbable by renormalization of physical parameters of the model. The global energy may be obtained by integrating the local energy density only when the latter is supplemented by an energy term residing precisely on the surface of the cylinder. The latter is identified as the integrated local energy density of the cylindrical shell when the latter is physically expanded to have finite thickness. Inside and outside the delta-function shell, the local energy density diverges as the surface of the shell is approached; the divergence is weakest when the conformal stress tensor is used to define the energy density. A real global divergence first occurs in O(λ3)\mathcal{O}(\lambda^3), as anticipated, but the proof is supplied here for the first time; this divergence is entirely associated with the surface energy, and does {\em not} reflect divergences in the local energy density as the surface is approached.Comment: 28 pages, REVTeX, no figures. Appendix added on perturbative divergence

    Identity complexity and integration in lesbian, gay, bisexual and heterosexual adolescents and emerging adults: Implications for clinical practice

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    The present study aimed at assessing whether differences exist in identity complexity and integration between 31 lesbian, gay, and bisexual (LGB) and 33 heterosexual youths (mean age 21.47, SD = 3.27), both Italian and US. Participants completed a newly created questionnaire, the Identity Labels and Life Contexts Questionnaire (ILLCQ), which assesses the interplay between identity dimensions and life contexts. The ILLCQ assesses identity integration on three levels: (a) integration among the different domains of identity in their intersection with the various life contexts (assessed through salience and centrality); (b) integration between an individual’s self-definition and the definition of self made by others (perceived self-recognition); and (c) the integration between how the person perceives her/himself to be and the way she/he shows her/himself to others. Results suggest that identity salience varies significantly across life contexts for both LGB and heterosexual youths. The only significant difference between the LGB and heterosexual groups was higher salience and centrality of the sexual orientation domain for LGB youths. Sexuality represents a core identity domain for LGB participants, and perhaps less so for heterosexual participants. LGB youths reported lower general identity recognition from other people. Implications for clinical practice are discussed

    Sexism, homophobia and transphobia in a sample of Italian pre-service teachers: the role of socio-demographic features

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    Although recent research has highlighted that lesbian, gay, bisexual and transgender (LGBT) youths represent a resilient population, they still suffer from social stigma and oppression, being potentially at additional risk of developing negative mental health outcomes. One of the main environments where violence and harassment against this population are present is the school. Within school contexts, the impact that teachers can have on the educational experiences of LGBT youths seems to be a crucial point. This paper explored sexist, homophobic and transphobic attitudes among 438 pre-service teachers in relation to specific socio-demographic features. Results indicated that being male, heterosexual, conservative and currently religious were positively associated with sexist, homophobic, and transphobic attitudes and feelings, and having a LGBT friend was negatively associated with homophobic and transphobic attitudes and feelings. These results suggest the need to introduce specific training on the deconstruction of gender and sexual stereotypes and prejudices, to provide teachers with efficient tools to address diversity in the classrooms and to implement inclusive school policies. Suggestions for the implementation of good practices are provided

    3D CAMERAS ACQUISITIONS FOR THE DOCUMENTATION OF CULTURAL HERITAGE

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    Abstract. Photography has always been considered as a valid tool to acquire information about reality. Nowadays, its versatility, together with the development of new techniques and technologies, allows to use it in different fields of application. Particularly, in the digitization of built heritage, photography not only enables to understand and document historical and architectural artifacts but also to acquire morphological and geometrical data about them with automated digital photogrammetry. Nowadays, photogrammetry enables many tools to give virtual casts of reality by showing it in the way of point cloud. Although they can have metric reliability and visual quality, traditional instruments &amp;ndash; such as monoscopic cameras &amp;ndash; involve a careful planning of the campaign phase and a long acquisition and processing time. On the contrary, the most recent ones, based on the integration of different sensors and cameras, try to reduce the gap between time and results. The latter include some systems of indoor mapping who, thanks to 360&amp;deg; acquisitions and SLAM technology, reconstruct the original scene in real time in great detail and with a photorealistic rendering. This study is aimed at reporting a research evaluating metric reliability and the level of survey detail with a Matterport Pro2 3D motorized rotating camera, equipped with SLAM technology, whose results have been compared with point clouds obtained by image-based and range-based processes.</p

    Heat Kernel Expansion for Semitransparent Boundaries

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    We study the heat kernel for an operator of Laplace type with a δ\delta-function potential concentrated on a closed surface. We derive the general form of the small tt asymptotics and calculate explicitly several first heat kernel coefficients.Comment: 16 page

    Group psychodynamic counselling with final-year undergraduates in clinical psychology: A clinical methodology to reinforce academic identity and psychological well-being

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    Educational institutions should ensure that students develop a professional identity, as well as safeguarding their well-being and activating awareness and change processes. The aim of this study was to assess the efficacy of group psychodynamic counselling as a means of reinforcing academic identity–considered the forerunner of professional identity–and psychological well-being in a group of final-year undergraduates studying clinical psychology. Thirty-three final-year-students of clinical psychology who participated in six group psychodynamic counselling sessions were compared with sixteen final-year students of clinical psychology who had never participated in an intervention of this kind. The results suggested that group psychodynamic counselling made students feel more capable of managing their lives and more open to new experiences as well as encouraging them to perceive their relationships as more positive and satisfying, to believe that their life is meaningful, and to achieve greater self-acceptance. The in-depth exploration also prompted students to consider their commitment to their choice of career. Group psychodynamic counselling also reinforced students’ educational choice, as the likelihood of students becoming less committed to this choice was reduced after the intervention. Thus, the study confirmed the efficacy of group psychodynamic counselling as a means of reinforcing both academic identity and promoting well-being and demonstrated that it is a tool clinical psychologists and university teachers could use to activate self-reflection and change within educational settings

    VPL FOR CULTURAL HERITAGE MONITORING: SAMPLING AND COMPARISON OF PHOTOGRAPHIC IMAGES

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    In the last decades, ICT strongly support cultural heritage conservation, management, valorisation and communication activities. Digital systems record series of data in real time, facilitating the automation of comparison, control and preventive evaluation activities aimed at the conscious management of the phenomenal reality based on the interrelationship between different information. According to these premises, this contribution presents first results of a research activity aimed at testing VPL parametric tools aimed at mapping environmental data and phenomena involving architectural surfaces and explicitating the comparison between data by graphical alert system. VPL tools are designed for a thematic image colour sampling. The main goal is monitoring the state of conservation of decorated architectural surfaces or artworks placed in unfavourable environmental conditions to facilitate preventive and intervention activities. The case study chosen to test this approach and digital tools is the fresco preserved in the Filangieri Hall of the State Archives in Naples
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