419 research outputs found

    Electronic structure of Pr0.67_{0.67}Ca0.33_{0.33}MnO3_3 near the Fermi level studied by ultraviolet photoelectron and x-ray absorption spectroscopy

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    We have investigated the temperature-dependent changes in the near-EEF_F occupied and unoccupied states of Pr0.67_{0.67}Ca0.33_{0.33}MnO3_3 which shows the presence of ferromagnetic and antiferromagnetic phases. The temperature-dependent changes in the charge and orbital degrees of freedom and associated changes in the Mn 3dd - O 2pp hybridization result in varied O 2pp contributions to the valence band. A quantitative estimate of the charge transfer energy (EECT_{CT}) shows a larger value compared to the earlier reported estimates. The charge localization causing the large EECT_{CT} is discussed in terms of different models including the electronic phase separation.Comment: 19 pages, 7 figures, To be published in Phy. Rev.

    Highly c-axis oriented growth of GaN film on sapphire (0001) by laser molecular beam epitaxy using HVPE grown GaN bulk target

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    Growth temperature dependant surface morphology and crystalline properties of the epitaxial GaN layers grown on pre-nitridated sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) were investigated in the range of 500-750 degrees C. The grown GaN films were characterized using high resolution x-ray diffraction, atomic force microscopy (AFM), micro-Raman spectroscopy, and secondary ion mass spectroscopy (SIMS). The x-ray rocking curve full width at a half maximum (FWHM) value for (0002) reflection dramatically decreased from 1582 arc sec to 153 arc sec when the growth temperature was increased from 500 degrees C to 600 degrees C and the value further decreased with increase of growth temperature up to 720 degrees C. A highly c-axis oriented GaN epitaxial film was obtained at 720 degrees C with a (0002) plane rocking curve FWHM value as low as 102 arc sec. From AFM studies, it is observed that the GaN grain size also increased with increasing growth temperature and flat, large lateral grains of size 200-300 nm was obtained for the film grown at 720 degrees C. The micro-Raman spectroscopy studies also exhibited the high-quality wurtzite nature of GaN film grown on sapphire at 720 degrees C. The SIMS measurements revealed a non-traceable amount of background oxygen impurity in the grown GaN films. The results show that the growth temperature strongly influences the surface morphology and crystalline quality of the epitaxial GaN films on sapphire grown by LMBE

    The project \u201cInteractive Topography of Dante\u2019s Inferno\u201d : transfer of knowledge and design of didactic tools

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    The project \u201ctopography of Dante\u2019s inferno\u201d is an experiment on alternative mode of access to a complex text relying on an evident topographical structure. The artifact (a website) is designed with the aim of introducing young students (11\u201314 years old) to a text usually read and studied by older students (16\u201319 years old). The design of the artifact was based on the theories of Sinsem\ueda applied to interaction design, and the testing focused on (1) usability and (2) on the understanding of the topography of the poem as a precondition for understanding the text

    Depression in partner caregivers of people with neurological conditions; associations with self-compassion and quality of life.

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    Objectives: Informal caregivers are vulnerable to poor mental health and quality of life (QoL). Self-compassion may protect against this. This study investigated depression and QoL in partner caregivers of people with a long-term or neurological condition (e.g. dementia or spinal cord injury) and explored the extent to which QoL and self-compassion are predictive of depression. Design: A cross-sectional, questionnaire design. Methods: Participants were recruited from charities and support groups. Partner caregivers (N = 57) completed assessments of depression, QoL, and self-compassion. Results: Over half (61.8%) of caregivers experienced at least mild symptoms of depression, illustrating high prevalence among caregivers compared with the general population. Overall QoL was poor compared with non-caregivers. QoL was poorest in the physical domain (M = 51.9, SD = 10.1) and highest in the environmental domain (M = 64.9, SD = 15.8). Both self-compassion and QoL were significant predictors of depression (p < 0.05), explaining 48.8% of the variance. Hours spent providing care was also significantly predictive of depression (p < 0.05). Conclusion: Self-compassion and QoL may be important targets for supportive interventions for this population. This study underscores the importance of developing supportive interventions for informal partner caregivers, and developing self-compassion in these

    The DISCOVER codec: Architecture, Techniques and Evaluation

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    Distributed Video Coding is becoming more and more popular among the research community, because of its interesting theoretical contributions and because there are still many open problems waiting to be solved. This paper introduces the codec architecture and the associated tools adopted by DISCOVER (DIStributed COding for Video sERvices), a European project which has been devoted to the advancement of Distributed Video Coding for two years. Along with the general description and pointers to references with more detailed information, this paper also presents some of the results obtained with the DISCOVER codec. An extended performance analysis and the codec’s executable file are both publicly available on the project’s web site www.discoverdvc.org

    Effectiveness of GenoType MTBDRsl in excluding TB drug resistance in a clinical trial

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    OBJECTIVES: To assess the performance of the GenoType MTBDRsl v1, a line-probe assay (LPA), to exclude baseline resistance to fluoroquinolones (FQs) and second-line injectables (SLIs) in the Standard Treatment Regimen of Anti-tuberculosis Drugs for Patients With MDR-TB 1 (STREAM 1) trial. METHODS: Direct sputum MTBDRsl results in the site laboratories were compared to indirect phenotypic drug susceptibility testing (pDST) results in the central laboratory, with DNA sequencing as a reference standard. RESULTS: Of 413 multidrug-resistant TB (MDR-TB) patients tested using MTBDRsl and pDST, 389 (94.2%) were FQ-susceptible and 7 (1.7%) FQ-resistant, while 17 (4.1%) had an inconclusive MTBDRsl result. For SLI, 372 (90.1%) were susceptible, 5 (1.2%) resistant and 36 (8.7%) inconclusive. There were 9 (2.3%) FQ discordant pDST/MTBDRsl results, of which 3 revealed a mutation and 5 (1.3%) SLI discordant pDST/MTBDRsl results, none of which were mutants on sequencing. Among the 17 FQ- and SLI MTBDRsl-inconclusive samples, sequencing showed 1 FQ- and zero SLI-resistant results, similar to frequencies among the conclusive MTBDRsl. The majority of inconclusive MTBDRsl results were associated with low bacillary load samples (acid-fast bacilli smear-negative or scantily positive) compared to conclusive results (P < 0.001). CONCLUSION: MTBDRsl can facilitate the rapid exclusion of FQ and SLI resistances for enrolment in clinical trials
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