133 research outputs found

    Structural, electronic and magnetic properties of SrRuO3_3 under epitaxial strain

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    Using density functional theory within the local spin density approximation, structural, electronic and magnetic properties of SRO are investigated. We examine the magnitude of the orthorhombic distortion in the ground state and also the effects of applying epitaxial constraints, whereby the influence of large (in the range of ±4\pm 4%) in-plane strain resulting from coherent epitaxy, for both [001] and [110] oriented films, have been isolated and investigated. The overall pattern of the structural relaxations reveal coherent distortions of the oxygen octahedra network, which determine stability of the magnetic moment on the Ru ion. The structural and magnetic parameters exhibit substantial changes allowing us to discuss the role of symmetry and possibilities of magneto-structural tuning of \SRO-based thin film structures.Comment: 11 page

    Si-compatible candidates for high-K dielectrics with the Pbnm perovskite structure

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    We analyze both experimentally (where possible) and theoretically from first-principles the dielectric tensor components and crystal structure of five classes of Pbnm perovskites. All of these materials are believed to be stable on silicon and are therefore promising candidates for high-K dielectrics. We also analyze the structure of these materials with various simple models, decompose the lattice contribution to the dielectric tensor into force constant matrix eigenmode contributions, explore a peculiar correlation between structural and dielectric anisotropies in these compounds and give phonon frequencies and infrared activities of those modes that are infrared-active. We find that CaZrO_3, SrZrO_3, LaHoO_3, and LaYO_3 are among the most promising candidates for high-K dielectrics among the compounds we considered.Comment: 17 pages, 9 figures, 4 tables. Supplementary information: http://link.aps.org/supplemental/10.1103/PhysRevB.82.064101 or http://www.physics.rutgers.edu/~sinisa/highk/supp.pd

    Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163^{163}Ho ions

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    For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of 163^{163}Ho using MMCs having the radioactive 163^{163}Ho ions implanted in the absorber. The implantation of 163^{163}Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. In addition an optimized detector design for future 163^{163}Ho experiments is presented

    In one’s own time: Contesting the temporality and linearity of bereavement

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    This article explores the experience and meaning of time from the perspective of caregivers who have recently been bereaved following the death of a family member. The study is situated within the broader cultural tendency to understand bereavement within the logic of stages, including the perception of bereavement as a somewhat predictable and certainly time-delimited ascent from a nadir in death to a ‘new normal’ once loss is accepted. Drawing on qualitative data from interviews with 15 bereaved family caregivers we challenge bereavement as a linear, temporally bound process, examining the multiple ways bereavement is experienced and how it variously resists ideas about the timeliness, desirability and even possibility of ‘recovery’. We posit, on the basis of these accounts, that the lived experience of bereavement offers considerable challenges to normative understandings of the social ties between the living and the dead and requires a broader reconceptualization of bereavement as an enduring affective state

    Assessing Internet addiction using the parsimonious Internet addiction components model - a preliminary study [forthcoming]

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    Internet usage has grown exponentially over the last decade. Research indicates that excessive Internet use can lead to symptoms associated with addiction. To date, assessment of potential Internet addiction has varied regarding populations studied and instruments used, making reliable prevalence estimations difficult. To overcome the present problems a preliminary study was conducted testing a parsimonious Internet addiction components model based on Griffiths’ addiction components (2005), including salience, mood modification, tolerance, withdrawal, conflict, and relapse. Two validated measures of Internet addiction were used (Compulsive Internet Use Scale [CIUS], Meerkerk et al., 2009, and Assessment for Internet and Computer Game Addiction Scale [AICA-S], Beutel et al., 2010) in two independent samples (ns = 3,105 and 2,257). The fit of the model was analysed using Confirmatory Factor Analysis. Results indicate that the Internet addiction components model fits the data in both samples well. The two sample/two instrument approach provides converging evidence concerning the degree to which the components model can organize the self-reported behavioural components of Internet addiction. Recommendations for future research include a more detailed assessment of tolerance as addiction component

    Portuguese validation of the Internet Addiction Test: An empirical study

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    Abstract Background and aims Research into Internet addiction (IA) has increased greatly over the last decade. Despite its various definitions and general lack of consensus regarding its conceptualisation amongst researchers, instruments for measuring this phenomenon have proliferated in a number of countries. There has been little research on IA in Portugal and this may be partly due to the absence of standardised measurement tools for assessing IA. Methods This study attempted to address this issue by adapting a Portuguese version of the Internet Addiction Test (IAT) via a translation-back translation process and Confirmatory Factor Analysis in a sample of 593 Portuguese students that completed a Portuguese version of the IAT along with questions related to socio-demographic variables. Results The findings suggested that the IAT appears to be a valid and reliable instrument for measuring IA among Portuguese young adults as demonstrated by its satisfactory psychometric properties. However, the present findings also suggest the need to reword and update some of the IAT's items. Prevalence of IA found in the sample was 1.2% and is discussed alongside findings relating to socio-demographic correlates. Limitations and implications of the present study are also discussed. Conclusions The present study calls for a reflection of the IAT while also contributing to a better understanding of the basic aspects of IA in the Portuguese community since many health practitioners are starting to realise that Internet use may pose a risk for some individuals

    Agreement on Web-based Diagnoses and Severity of Mental Health Problems in Norwegian Child and Adolescent Mental Health Services

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    Objective: This study examined the agreement between diagnoses and severity ratings assigned by clinicians using a structured web-based interview within a child and adolescent mental health outpatient setting. Method: Information on 100 youths was obtained from multiple informants through a web-based Development and Well-Being Assessment (DAWBA). Based on this information, four experienced clinicians independently diagnosed (according to the International Classification of Diseases Revision 10) and rated the severity of mental health problems according to the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) and the Children’s Global Assessment Scale (C-GAS). Results: Agreement for diagnosis was κ=0.69-0.82. Intra-class correlation for single measures was 0.78 for HoNOSCA and 0.74 for C-GAS, and 0.93 and 0.92, respectively for average measures. Conclusions: Agreement was good to excellent for all diagnostic categories. Agreement for severity was moderate, but improved to substantial when the average of the ratings given by all clinicians was considered. Therefore, we conclude that experienced clinicians can assign reliable diagnoses and assess severity based on DAWBA data collected online
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