1,283 research outputs found

    Surface transfer doped diamond diodes with metal oxide passivation and field-plate

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    Surface transfer-doping, involving hydrogen terminated diamond surfaces, has been an effective method for producing diamond devices for some years but suffered from poor device longevity and reproducibility. The emergence of metal oxides as an encapsulant has begun to change this situation. Here, HfO2 encapsulated surface transfer doped diamond Schottky diodes with stable device characteristics have been demonstrated. Ideality factor and Schottky barrier heights of the devices did not vary considerably across extended periods of use (up to 39 days). The devices showed excellent blocking capabilities, demonstrating no catastrophic breakdown under the maximum field applied and only a slight increase in leakage current at the reverse bias and field strength of 200 V and 0.167 MV cm−1 , respectively. Indeed, a large rectification ratio of up to 108 and a very low leakage current of ≈10−9 A cm−1 were maintained at this reverse bias (200 V). Furthermore, multiple devices were compared across a single substrate, something rarely reported previously for surface transfer doped diamond diodes. Leakage currents and rectification ratios were similar for all of the devices. The authors are grateful to the UKs Engineering and Physical Sciences Research Council (EPSRC) and BAE Systems Marine Ltd. for the award of a “Cooperative Awards in Science and Engineering (CASE)” Ph.D. Studentship for R.J.W. and to EPSRC for the award of related research funding (No. EP/H020055/1). A.C.P.-T. and R.B.J. also acknowledge invaluable assistance, both financial and in the form of international collaborations, from the European Commission Horizon 2020 Project “GREENDIAMOND” (H2020 Large Project under Grant No. SEP-210184415). Lambda Photometrics Ltd. and Everbeing International Corporation are gratefully acknowledged for use of a Everbeing EB-6 DC probe station. Finally, the LCN Cleanroom is acknowledged for the invaluable assistance of technicians and for the use of the ALD, evaporation, and photo-lithography tools

    Effects of Mindfulness-Based Cognitive Therapy on Specificity of Life Goals

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    This study explored the immediate effects of a course of Mindfulness-Based Cognitive Therapy (MBCT) for chronically depressed participants with a history of suicidality on the specificity of important goals for the future. Participants were randomly allocated to immediate treatment with MBCT or to a waitlist condition and life goals were assessed both before and after the treatment or waiting period. Results showed that participants receiving MBCT reported significantly more specific goals post-treatment whereas those allocated to the waitlist condition showed no significant change. Similarly, participants allocated to MBCT regarded themselves as significantly more likely to achieve their important goals post-treatment, whilst again there was no significant change in the waitlist group. Increases in goal specificity were associated with parallel increases in autobiographical memory specificity whereas increases in goal likelihood were associated with reductions in depressed mood. These results suggest that MBCT may enable participants to clarify their important goals and in doing so increase their confidence in their capacity to move in valued life directions

    Cross-Cultural Validation of the Inventory of School Motivation (ISM) in the Asian Setting: Hong Kong and the Philippines

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    Students’ achievement goals in school have received increasing research attention because they have been shown to be important in predicting important outcomes. As such, there has been a growing interest in measuring and comparing them across different cultural groups. However, these comparisons cannot be made until validity evidence has been attained to support the use of an instrument in the new cultural setting. In this study, we investigated the cross-cultural applicability of the Inventory of School Motivation (ISM, McInerney et al. American Educational Research Journal 34:207-236, 1997) in the Hong Kong Chinese and Philippine contexts using both within-network and between-network approaches to construct validation. The ISM measures four types of achievement goals: mastery, performance, social, and extrinsic goals. 1,406 high school students from Hong Kong (n = 697) and the Philippines (n = 709) participated. Results of the within-network test showed that the ISM had good internal consistency reliability and the confirmatory factor analysis provided support for the hypothesized four-factor model. Multigroup confirmatory factor analyses supported invariance of factor loadings across the two samples. The between-network test also indicated that these achievement goals correlated systematically with different aspects of students’ self-concepts. These findings support the applicability of the ISM among Hong Kong Chinese and Filipino students

    Supplementation-induced increase in circulating omega-3 serum levels is not associated with a reduction in depressive symptoms: Results from the MooDFOOD depression prevention trial

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    This is the final version. Available from Wiley via the DOI in this record.The data that support the findings of this study are available from the corresponding author upon reasonable request.Background: There is ambiguity on how omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are associated with depression, and what the temporality of the association might be. The present study aimed to examine whether (intervention-induced changes in) n-3 PUFA levels were associated with (changes in) depressive symptoms. Methods: Baseline, 6- and 12-month follow-up data on 682 overweight and subclinically depressed persons from four European countries that participated in the MooDFOOD depression prevention randomized controlled trial were used. Participants were allocated to four intervention groups: (a) placebos, (b) placebos and food-related behavioral activation therapy (F-BA), (c) multinutrient supplements (fish oil and multivitamin), and (d) multinutrient supplements and F-BA. Depressive symptoms were measured using the inventory of depressive symptomatology. PUFA levels (µmol/L) were measured using gas chromatography. Analyses were adjusted for sociodemographics, lifestyle, and somatic health. Results: Increases in n-3 PUFA, docosahexaenoic acid, and eicosapentaenoic acid levels over time were significantly larger in the supplement groups than in placebo groups. Change in PUFA levels was not significantly associated with the change in depressive symptoms (β =.002, SE = 0.003, p =.39; β =.003, SE = 0.005, p =.64; β =.005, SE = 0.005, p =.29; β = −.0002, SE = 0.0004, p =.69). Baseline PUFA levels did not modify the intervention effects on depressive symptoms. Conclusions: In overweight and subclinical depressed persons, multinutrient supplements led to significant increases in n-3 PUFA levels over time, which were not associated with changes in depressive symptoms. Multinutrient supplements do not seem to be an effective preventive strategy in lowering depressive symptoms over time in these at-risk groups.European UnionNational Institute for Health Research (NIHR

    Precision Measurement of the Mass of the h_c(1P1) State of Charmonium

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    A precision measurement of the mass of the h_c(1P1) state of charmonium has been made using a sample of 24.5 million psi(2S) events produced in e+e- annihilation at CESR. The reaction used was psi(2S) -> pi0 h_c, pi0 -> gamma gamma, h_c -> gamma eta_c, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_c decays are reconstructed in fifteen hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_c)=3525.28+-0.19 (stat)+-0.12(syst) MeV, and B(psi(2S) -> pi0 h_c)xB(h_c -> gamma eta_c)= (4.19+-0.32+-0.45)x10^-4. Using the 3PJ centroid mass, Delta M_hf(1P)= - M(h_c) = +0.02+-0.19+-0.13 MeV.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS/, submitted to PR

    Precision Measurement of B(D+ -> mu+ nu) and the Pseudoscalar Decay Constant fD+

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    We measure the branching ratio of the purely leptonic decay of the D+ meson with unprecedented precision as B(D+ -> mu+ nu) = (3.82 +/- 0.32 +/- 0.09)x10^(-4), using 818/pb of data taken on the psi(3770) resonance with the CLEO-c detector at the CESR collider. We use this determination to derive a value for the pseudoscalar decay constant fD+, combining with measurements of the D+ lifetime and assuming |Vcd| = |Vus|. We find fD+ = (205.8 +/- 8.5 +/- 2.5) MeV. The decay rate asymmetry [B(D+ -> mu+ nu)-B(D- -> mu- nu)]/[B(D+ -> mu+ nu)+B(D- -> mu- nu)] = 0.08 +/- 0.08, consistent with no CP violation. We also set 90% confidence level upper limits on B(D+ -> tau+ nu) < 1.2x10^(-3) and B(D+ -> e+ nu) < 8.8x10^(-6).Comment: 24 pages, 11 figures and 6 tables, v2 replaced some figure vertical axis scales, v3 corrections from PRD revie
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