2,383 research outputs found

    Nonstoichiometric doping and Bi antisite defect in single crystal Bi2Se3

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    We studied the defects of Bi2Se3 generated from Bridgman growth of stoichiometric and nonstoichiometric self-fluxes. Growth habit, lattice size, and transport properties are strongly affected by the types of defect generated. Major defect types of Bi_Se antisite and partial Bi_2-layer intercalation are identified through combined studies of direct atomic-scale imaging with scanning transmission electron microscopy (STEM) in conjunction with energy-dispersive X-ray spectroscopy (STEM-EDX), X-ray diffraction, and Hall effect measurements. We propose a consistent explanation to the origin of defect type, growth morphology, and transport property.Comment: 5 pages, 5 figure

    Meta-analysis of gene-based genome-wide association studies of bone mineral density in Chinese and European subjects

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    Summary Gene-based association approach could be regarded as a complementary analysis to the single SNP association analysis. We meta-analyzed the findings from the gene-based association approach using the genome-wide association studies (GWAS) data from Chinese and European subjects, confirmed several well established bone mineral density (BMD) genes, and suggested several novel BMD genes. Introduction The introduction of GWAS has greatly increased the number of genes that are known to be associated with common diseases. Nonetheless, such a single SNP GWAS has a lower power to detect genes with multiple causal variants. We aimed to assess the association of each gene with BMD variation at the spine and hip using gene-based GWAS approach. Methods We studied 778 Hong Kong Southern Chinese (HKSC) women and 5,858 Northern Europeans (dCG); age, sex, and weight were adjusted in the model. The main outcome measure was BMD at the spine and hip. Results Nine genes showed suggestive p value in HKSC, while 4 and 17 genes showed significant and suggestive p values respectively in dCG. Meta-analysis using weighted Z-transformed test confirmed several known BMD genes and suggested some novel ones at 1q21.3, 9q22, 9q33.2, 20p13, and 20q12. Top BMD genes were significantly associated with connective tissue, skeletal, and muscular system development and function (p<0.05). Gene network inference revealed that a large number of these genes were significantly connected with each other to form a functional gene network, and several signaling pathways were strongly connected with these gene networks. Conclusion Our gene-based GWAS confirmed several BMD genes and suggested several novel BMD genes. Genetic contribution to BMD variation may operate through multiple genes identified in this study in functional gene networks. This finding may be useful in identifying and prioritizing candidate genes/loci for further study. © International Osteoporosis Foundation and National Osteoporosis Foundation 2011.published_or_final_versionSpringer Open Choice, 21 Feb 201

    Teacher–researcher partnership in the translation and implementing of PALS (Peer‐Assisted Learning Strategies): An international perspective

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    Funding Information: We would like to thank the schools, teachers and students who have alongside us developed PALS for each international context outlined. Publisher Copyright: © 2022 The Authors. Journal of Research in Reading published by John Wiley & Sons Ltd on behalf of United Kingdom Literacy Association.Peer-Assisted Learning Strategies (PALS) is a class-wide structured supplementary paired reading programme to support learners with their reading (Fuchs et al., 1997). What remains at the core of implementing PALS in any given location is the co-creation with teachers to ensure PALS fits with that educational context. This paper discusses the involvement of teachers as co-creators in the process of adapting PALS in England, United Arab Emirates (UAE), Taiwan and Iceland. The aim is to demonstrate the importance of careful adaptation when implementing a programme adopted from another country. Each adaption used a different methodological approach to co-creation. For example, in England, field notes, informal conversations and interviews were utilised for co-creation. In Iceland, preschool and elementary teachers were instrumental in translating and adapting the PALS materials to the Icelandic context. From each adaption, the teachers supported the development of a literacy programme that was suitable for classroom use. In England, teachers' involvement resulted in the removal of the motivational point system. For the UAE context, PALS began in English to support second language learning, but the instructional routines were a good ‘fit’ for the school culture and were developed in Arabic. For the Taiwan context, PALS provided an empirical basis for a model of differentiated instruction to enhance the reading literacy of Chinese-speaking elementary students. In Iceland, teachers trained other teachers in PALS as a research-based and efficient approach to meeting diverse learning needs of students, especially those with Icelandic as an additional language. Careful adaptation, piloting and the involvement of key stakeholders is important for the successful implementation of a reading programme.Peer reviewe

    Bone mineral density enhances use of clinical risk factors in predicting ten-year risk of osteoporotic fractures in Chinese men: the Hong Kong Osteoporosis Study

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    This prospective study aimed to determine the risk factors and the 10-year probability of osteoporotic fracture in Southern Chinese men. The findings show substantial population differences in fracture incidence and risk prediction compared to the FRAX TM model, and the addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men. Introduction: Clinical risk factors with or without bone mineral density (BMD) measurements are increasingly recognized as reliable predictors of fracture risk. Prospective data on fracture incidence in Asian men remain sparse. This prospective study aimed to determine the risk factors and the 10-year absolute fracture risk in Southern Chinese men. Methods: This is a part of the Hong Kong Osteoporosis Study. One thousand eight hundred ten (1,810) community-dwelling, treatment-naive men aged 50 years or above were evaluated. Baseline demographic characteristics, clinical risk factors and BMD were recorded. Ten-year risk of osteoporotic fracture was calculated using Cox proportional hazards models. Results: The mean age of subjects was 68.0 ± 10.3 years. After a mean follow-up period of 3.5±2.9 years (range 1 to 14 years), 37 incident low-trauma fractures were recorded. The incidence for all osteoporotic fractures and hip fractures was 635/100,000 and 123/100,000 person-years, respectively. The most significant predictors of osteoporotic fracture were history of fall (RR 14.5), femoral neck BMD T-score < -2.5 (RR 13.8) and history of fracture (RR 4.4). Each SD reduction in BMD was associated with a 1.8 to 2.6-fold increase in fracture risk. Subjects with seven clinical risk factors and BMD T-score of -1 had an absolute 10-year risk of osteoporotic fracture of 8.9%, but this increased to 22.7% if they also had a femoral neck BMD T-score of -2.5. Conclusions: These findings show substantial population differences in fracture incidence and risk prediction. The addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

    Wave functions for arbitrary operator ordering in the de Sitter minisuperspace approximation

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    We derive exact series solutions for the Wheeler-DeWitt equation corresponding to a spatially closed Friedmann-Robertson-Walker universe with cosmological constant for arbitrary operator ordering of the scale factor of the universe. The resulting wave functions are those relevant to the approximation which has been widely used in two-dimensional minisuperspace models with an inflationary scalar field for the purpose of predicting the period of inflation which results from competing boundary condition proposals for the wave function of the universe. The problem that Vilenkin's tunneling wave function is not normalizable for general operator orderings, is shown to persist for other values of the spatial curvature, and when additional matter degrees of freedom such as radiation are included.Comment: 12 pages, revTeX-3.
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