University of Wollongong

About: University of Wollongong is a education organization based out in Wollongong, New South Wales, Australia. It is known for research contribution in the topics: Population & Graphene. The organization has 15674 authors who have published 46658 publications receiving 1197471 citations. The organization is also known as: UOW & Wollongong University.

Improved ferroelectric properties in multiferroic BiFeO3 thin films through La and Nb codoping

Abstract: We report the significant improvement of the ferroelectric properties of $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ thin film through control of electrical leakage by Nb doping. A very large remanent electrical polarization value of $80\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{C}∕{\mathrm{cm}}^{2}$ was observed in ${\mathrm{Bi}}_{0.8}{\mathrm{La}}_{0.2}{\mathrm{Nb}}_{0.01}{\mathrm{Fe}}_{0.99}{\mathrm{O}}_{3}$ thin film on $\mathrm{Pt}∕\mathrm{Ti}∕\mathrm{Si}{\mathrm{O}}_{2}∕\mathrm{Si}$ substrate. The doping effect of Nb in reducing the movable charge density due to oxygen vacancies in $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ was confirmed by the dielectric measurements. A very small loss was observed in the Nb and La codoped $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ thin film. As well as the improvement in the ferroelectric properties, the magnetic moment was also enhanced due to the doping of La.

Objectively measured sedentary behaviour and health and development in children and adolescents: systematic review and meta-analysis

Abstract: Sedentary behaviour has emerged as a unique determinant of health in adults. Studies in children and adolescents have been less consistent. We reviewed the evidence to determine if the total volume and patterns (i.e. breaks and bouts) of objectively measured sedentary behaviour were associated with adverse health outcomes in young people, independent of moderate-intensity to vigorous-intensity physical activity. Four electronic databases (EMBASE MEDLINE, Ovid EMBASE, PubMed and Scopus) were searched (up to 12 November 2015) to retrieve studies among 2- to 18-year-olds, which used cross-sectional, longitudinal or experimental designs, and examined associations with health outcomes (adiposity, cardio-metabolic, fitness, respiratory, bone/musculoskeletal, psychosocial, cognition/academic achievement, gross motor development and other outcomes). Based on 88 eligible observational studies, level of evidence grading and quantitative meta-analyses indicated that there is limited available evidence that the total volume or patterns of sedentary behaviour are associated with health in children and adolescents when accounting for moderate-intensity to vigorous-intensity physical activity or focusing on studies with low risk of bias. Quality evidence from studies with robust designs and methods, objective measures of sitting, examining associations for various health outcomes, is needed to better understand if the overall volume or patterns of sedentary behaviour are independent determinants of health in children and adolescents.

A development research agenda for online collaborative learning

Abstract: Although important, traditional basic-to-applied research methods have provided an insufficient basis for advancing the design and implementation of innovative collaborative learning environments. It is proposed that more progress may be accomplished through development research or design research. Development research protocols require intensive and long-term collaboration among researchers and practitioners. In this article, we propose guidelines for implementing development research models more widely, and conclude with a prescription for an online collaborative learning research agenda for the next five to ten years.

Smooth Tests of Goodness of Fit

Abstract: Summary A comprehensive approach to goodness of fit testing is possible using the smooth tests described in detail in Rayner & Best (1989). Here we give an overview of this area and demonstrate the power and flexibility of the smooth tests. Our emphasis is on the use of orthonormal functions, tests for composite hypotheses, and tests of categorised data. We have developed tests for families of distributions, such as the univariate and multivariate normal, exponential and Poisson. The tests are essentially omnibus tests but the components provide useful and powerful directional tests. The history of the smooth tests of goodness of fit is reviewed from Neyman (1937), through to Lancaster, to Thomas, Kopecky and Pierce, and to Rayner and Best. The formulation of categorised smooth models leads to X2 tests and their components. A generalisation of the smooth categorised model, when allied with Hall's (1985) idea of overlapping, leads to focused tests, and to an alternative to pooling. Examples are taken from D'Agostino & Stephens (1986), who have several different contributors and therefore approaches, none of which is recommended above the others. Our resolution is simple: don't use those other methods-use a smooth test!