130 research outputs found

    Injectivity of sections of convex harmonic mappings and convolution theorems

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    In the article the authors consider the class H0{\mathcal H}_0 of sense-preserving harmonic functions f=h+gf=h+\overline{g} defined in the unit disk z<1|z|<1 and normalized so that h(0)=0=h(0)1h(0)=0=h'(0)-1 and g(0)=0=g(0)g(0)=0=g'(0), where hh and gg are analytic in the unit disk. In the first part of the article we present two classes PH0(α)\mathcal{P}_H^0(\alpha) and GH0(β)\mathcal{G}_H^0(\beta) of functions from H0{\mathcal H}_0 and show that if fPH0(α)f\in \mathcal{P}_H^0(\alpha) and FGH0(β)F\in\mathcal{G}_H^0(\beta), then the harmonic convolution is a univalent and close-to-convex harmonic function in the unit disk provided certain conditions for parameters α\alpha and β\beta are satisfied. In the second part we study the harmonic sections (partial sums) sn,n(f)(z)=sn(h)(z)+sn(g)(z), s_{n, n}(f)(z)=s_n(h)(z)+\overline{s_n(g)(z)}, where f=h+gH0f=h+\overline{g}\in {\mathcal H}_0, sn(h)s_n(h) and sn(g)s_n(g) denote the nn-th partial sums of hh and gg, respectively. We prove, among others, that if f=h+gH0f=h+\overline{g}\in{\mathcal H}_0 is a univalent harmonic convex mapping, then sn,n(f)s_{n, n}(f) is univalent and close-to-convex in the disk z<1/4|z|< 1/4 for n2n\geq 2, and sn,n(f)s_{n, n}(f) is also convex in the disk z<1/4|z|< 1/4 for n2n\geq2 and n3n\neq 3. Moreover, we show that the section s3,3(f)s_{3,3}(f) of fCH0f\in {\mathcal C}_H^0 is not convex in the disk z<1/4|z|<1/4 but is shown to be convex in a smaller disk.Comment: 16 pages, 3 figures; To appear in Czechoslovak Mathematical Journa

    Capture the fracture: a best practice framework and global campaign to break the fragility fracture cycle

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    Summary The International Osteoporosis Foundation (IOF) Capture the Fracture Campaign aims to support implementation of Fracture Liaison Services (FLS) throughout the world. Introduction FLS have been shown to close the ubiquitous secondary fracture prevention care gap, ensuring that fragility fracture sufferers receive appropriate assessment and intervention to reduce future fracture risk. Methods Capture the Fracture has developed internationally endorsed standards for best practice, will facilitate change at the national level to drive adoption of FLS and increase awareness of the challenges and opportunities presented by secondary fracture prevention to key stakeholders. The Best Practice Framework (BPF) sets an international benchmark for FLS, which defines essential and aspirational elements of service delivery. Results The BPF has been reviewed by leading experts from many countries and subject to beta-testing to ensure that it is internationally relevant and fit-for-purpose. The BPF will also serve as a measurement tool for IOF to award ‘Capture the Fracture Best Practice Recognition’ to celebrate successful FLS worldwide and drive service development in areas of unmet need. The Capture the Fracture website will provide a suite of resources related to FLS and secondary fracture prevention, which will be updated as new materials become available. A mentoring programme will enable those in the early stages of development of FLS to learn from colleagues elsewhere that have achieved Best Practice Recognition. A grant programme is in development to aid clinical systems which require financial assistance to establish FLS in their localities. Conclusion Nearly half a billion people will reach retirement age during the next 20 years. IOF has developed Capture the Fracture because this is the single most important thing that can be done to directly improve patient care, of both women and men, and reduce the spiralling fracture-related care costs worldwide.</p

    Measurement invariance of Personal Well-Being Index (PWI-8) across 26 countries

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    This report examines the measurement invariance of the Personal Well-being Index with 8 items (PWI-8). University students (N = 5731) from 26 countries completed the measure either through paper and pencil or electronic mode. We examined uni-dimensional structure of PWI and performed a Multi-group CFA to assess the measurement invariance across the 26 countries, using conventional approach and the alignment procedure. The findings provide evidence of configural and partial metric invariance, as well as partial scalar invariance across samples. The findings suggest that PWI-8 can be used to examine correlates of life satisfaction across all included countries, however it is impossible to compare raw scores across countries

    The mental health continuum-short form: the structure and application for cross-cultural studies-A 38 nation study

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    Objective: The Mental Health Continuum-Short Form (MHC-SF) is a brief scale measuring positive human functioning. The study aimed to examine the factor structure and to explore the cross-cultural utility of the MHC-SF using bifactor models and exploratory structural equation modelling. Method: Using multigroup confirmatory analysis (MGCFA) we examined the measurement invariance of the MHC-SF in 38 countries (university students, N = 8,066; 61.73% women, mean age 21.55 years). Results: MGCFA supported the cross-cultural replicability of a bifactor structure and a metric level of invariance between student samples. The average proportion of variance explained by the general factor was high (ECV =.66), suggesting that the three aspects of mental health (emotional, social, and psychological well-being) can be treated as a single dimension of well-being. Conclusion: The metric level of invariance offers the possibility of comparing correlates and predictors of positive mental functioning across countries; however, the comparison of the levels of mental health across countries is not possible due to lack of scalar invariance. Our study has preliminary character and could serve as an initial assessment of the structure of the MHC-SF across different cultural settings. Further studies on general populations are required for extending our findings.info:eu-repo/semantics/acceptedVersio

    Belief in a zero-sum game and subjective well-being across 35 countries

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    This article presents a short research report on the relationship between perceived antagonism in social relations measured using the Belief in a Zero-Sum Game (BZSG) scale, life satisfaction, and positive and negative affect. Given that individuals who believe that life is like a zero-sum game are likely to perceive their daily interactions with others as unfair, we expected that individuals with high BZSG experience more negative affect and fewer positive one, resulting in a lower satisfaction with life. In addition, we examined whether country-level BZSG may play a moderating role in these associations. Data were collected from student samples (N = 7146) in 35 countries. Multilevel modelling revealed that perceived social antagonism in social relations is negatively associated with satisfaction with life and that this relationship is mediated by both positive and negative affect at the individual level. The relation of individual BZSG and negative affect on satisfaction with life were weaker in societies with higher country-level BZSG, suggesting that the effects of BZSG may be less detrimental in these countries. These findings extend previous knowledge about predictors of life satisfaction and suggest that social beliefs might also be an important factor that influences subjective well-being. The contribution of the study is that the separate treatment of life satisfaction and positive and negative affect may be helpful in many research situations, particularly from a cross-cultural perspective.info:eu-repo/semantics/publishedVersio
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