| 5671. |
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| 5672. |
- Gunnarsson, Robert, 1972-
(författare)
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The model of the particle nature of matter in science and science education
- 2014
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Konferensbidrag (refereegranskat)abstract
- The model of the particle nature of matter has been one of the fundaments in science and science education. This model describes matter as being composed of small hard solid entities - particles - often known as atoms and molecules, clinging to each other or moving around in empty space. However, from a scientific point of view there are problems with this model; for instance, quantum mechanics describes atoms as having both particle as well as wave properties implying that the entities are neither hard nor solid. The particle nature of matter model is also facing problems within science education. Students’ conceptions of the concept of particle appears to be limited.In this talk I will describe how science teachers’ understanding of the model of the particle nature of matter is limited too. Eleven secondary school science teachers were interviewed about their arguments for the particle nature of matter. Although the teachers appears to have an epistemological understanding of the concept of models in science they give vague arguments for the particle nature of matter model. Particularly, they have problems justifying the model from specific experiments. The model of the particle nature of matter is discussed in the light of these interview data, but also in the light of historical arguments and verifications of the model.
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| 5673. |
- Gunnarsson, Robert, 1972-, et al.
(författare)
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Useless brackets in arithmetic expressions with mixed operations
- 2012
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Ingår i: Proceedings of the 36th Conference of the International Group for the Psychology of Mathematics Education. - : The International Group for the Psychology of mathematics Education. ; , s. 2-275-2-282
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Konferensbidrag (refereegranskat)abstract
- There can be different intentions with brackets in mathematical expressions. It has previously been suggested that mathematically useless brackets can be educationally useful when learning the order of operations in expressions with mixed operations. This paper reports how students (12-13 years) deal with the implicit mental conflict between brackets as a necessary part of the order of operations and brackets to emphasize precedence. The students taking part in this quasi-experimental study were instructed on the order of operations, but were also indirectly exposed to different use of brackets. It is concluded that emphasizing brackets impede the transfer from a left-to-right computation strategy to the use of precedence rules.
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| 5674. |
- Gunnarsson Sarius, Niklas, et al.
(författare)
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Electrochemically based low-cost high precision processing in MOEMS packaging
- 2009
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 54:9, s. 2458-2465
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Tidskriftsartikel (refereegranskat)abstract
- Precision processing in MOEMS (micro-opto-electromechanical systems) packaging has been studied based on electrochemical processes with the purpose of establishing technology for low-cost multifunctional encapsulation of microsystems and assembly of opto-electric access links in polymer. The electrochemically based processes studied in this paper include: 1. Electroforming of a polymer moulding tool (stamper) in a nickel sulphamate electrolyte on a highprecision 3D etched silicon template. 2. Patterning of 3D surfaces by an electrophoretic photoresist. 3. Precision plating of Au and Sn for self-alignment of chips by eutectic Au-Sn solder. The results show that nickel stampers with adequately low internal stress can be electroformed on 3D silicon wafers. Furthermore, 3D polymer samples manufactured by the nickel stampers can be patterned with metal lines down to 20 mu m width using electrophoretic photoresist. Finally, eutectic Au-Sn solder bumps are realized by electroplating of Au and Sn followed by reflowing, satisfying the demands on dimension and alloy composition control over a 4 in. Si wafer.
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| 5675. |
- Guo, Cheng, 1985-, et al.
(författare)
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Adolescent mental health policies in Sweden and China : a comparative study
- 2017
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Ingår i: European Journal of Public Health, 27, issue supplement 3, 1. - : Oxford University Press.
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Konferensbidrag (refereegranskat)abstract
- BackgroundBoth Sweden and China face challenges of decreasing mental health among adolescents, although the two countries are very different in political system, income level, number of population and national culture traits. To the best of our knowledge, this is the first comparative study of implementation of adolescent mental health policies in Sweden and China.AimTo describe and compare how adolescent mental health policies in Sweden and China are implemented. Our more specific research question was to find out how Sweden and China differ from each other regarding context, policy implementation process, content and actors in adolescent mental health.MethodsQualitative semi-structured interviews on policy actors from Västerås, Sweden and Weifang, China and policy document analysis were conducted.ResultsIn both countries, the national level coordinates strategies and interventions on the regional and local levels. In Sweden, this is done by means of funding for intersectoral work and by establishing cooperation between several policy-actors on different levels. The Swedish policymakers on the national level gives the regional and local level actors a certain amount of freedom to organise their activities provided that actors cooperate. In China, the national coordination aims for interventions for improvement of adolescent mental health in one sector, the educational organisation, and the actions of policy actors are guided in detail to a higher degree. The content of the Swedish adolescent mental health policy documents focus on counselling adolescents, while the Chinese documents focus on knowledge dissemination.ConclusionsThe policy implementation of the two countries differs in number of actors involved, and the freedom given to regional and policy actors to perform interventions. In both countries, schools play a crucial part in policy implementation.Key messages:The adolescent mental health policies in Sweden and China are compared in policy context, implementation process, content and actors based on the policy triangle framework.The policy systems in these two countries share similarities in several aspects and also show differences in other parts.
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| 5676. |
- Guo, Cheng, et al.
(författare)
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Prevalence and correlates of positive mental health in Chinese adolescents
- 2018
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Ingår i: BMC Public Health. - : BioMed Central. - 1471-2458. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies investigating the prevalence of positive mental health and its correlates are still scarce compared to the studies on mental disorders, although there is growing interest of assessing positive mental health in adolescents. So far, no other study examining the prevalence and determinants of positive mental health in Chinese adolescents has been found. The purpose of this study was to assess the prevalence and correlates of positive mental health in Chinese adolescents.Methods: This cross-sectional study used a questionnaire including Mental Health Continuum-Short Form (MHC-SF) and items regarding multiple aspects of adolescent life. The sample involved a total of 5399 students from grade 8 and 10 in Weifang, China. Multivariate Logistic regression analyses were performed to evaluate the associations between potential indicators regarding socio-economic situations, life style, social support and school life and positive mental health and calculate odds ratios and 95% confidence intervals.Results: More than half (57.4%) of the participants were diagnosed as flourishing. The correlated factors of positive mental health in regression models included gender, perceived family economy, the occurrence of sibling(s), satisfaction of self-appearance, physical activity, sleep quality, stress, social trust, desire to learn, support from teachers and parents as well as whether being bullied at school (OR ranging from 1.23 to 2.75). The Hosmer-Lemeshow p-value for the final regression model (0.45) indicated adequate model fit.Conclusion: This study gives the first overview on prevalence and correlates of positive mental health in Chinese adolescents. The prevalence of positive mental health in Chinese adolescents is higher than reported in most of the previous studies also using MHC-SF. Our findings suggest that adolescents with advantageous socio-economic situations, life style, social support and school life are experiencing better positive mental health than others.
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| 5677. |
- Guo, Cheng, et al.
(författare)
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Promotion by Education : Adolescent Mental Health Policy Translation in a Local Context of China
- 2020
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Ingår i: Administration and Policy in Mental Health and Mental Health Services Research. - : Springer. - 0894-587X .- 1573-3289. ; 47:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to describe how Chinese national adolescent mental health policy is translated into local plans and practice by means of the theoretical perspective of the policy triangle. Document analysis of national, provincial and local policy documents and semi-structured interviews with local policy actors were performed. National policies were implemented by a top-down process. The ministries were strong policy-makers on the national level, while the policy actors at the local level were mainly found in the educational sector. The content of the policy actions was moral education, knowledge dissemination and learning, rather than counselling and treatment.
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| 5678. |
- Guo, Cheng, et al.
(författare)
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Psychometric evaluation of the Mental Health Continuum-Short Form (MHC-SF) in Chinese adolescents : a methodological study
- 2015
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Ingår i: Health and Quality of Life Outcomes. - : BioMed Central. - 1477-7525 .- 1477-7525. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: In epidemiological surveillance of mental health there is good reason to also include scales that measure the presence of well-being rather than merely symptoms of ill health. The Mental Health Continuum-Short Form (MHC-SF) is a self-reported scale to measure emotional, psychological and social well-being and conduct categorical diagnosis of positive mental health. This particular instrument includes the three core components of the World Health Organization's definition of mental health and had previously not been psychometrically evaluated on adolescents in China.Methods: In total 5,399 students (51.1% female) from schools in the urban areas of Weifang in China were included in the study (mean age = 15.13, SD = 1.56). Participants completed a comprehensive questionnaire with several scales, among them the MHC-SF. Statistical analyses to evaluate reliability, structural validity, measurement invariance, presence of floor and ceiling effects and to some extent external validity of the MHC-SF were carried out.Results: The Cronbach's α coefficients for sub-scales as well as the total scale were all above 0.80 indicating good reliability. Confirmative factor analysis confirmed the three-dimensional structure of the Chinese version of MHC-SF and supported the configural and metric invariance across gender and age. Noteworthy ceiling effects were observed for single items and sub-scales although not for the total scale. More importantly, observed floor effects were negligible. The stronger correlation found between MHC-SF and Minneapolis-Manchester Quality of Life Instrument (as measure of positive mental health) than between MHC-SF and Hospital Anxiety Depression Scale (as measure of mental illness and distress) yielded support for external validity.Conclusion: In conclusion, the main findings of this study are in line with studies from other countries that evaluated the psychometric properties of the MHC-SF and show that this instrument, that includes the three core components of the WHO definition of mental health, is useful in assessing positive adolescent mental health also in China.
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| 5679. |
- Guo, Yu, et al.
(författare)
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A priori knowledge based frequency-domain quantification of Magnetic Resonance Spectroscopy
- 2009
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Ingår i: Proceedings of the 7th IFAC Symposium onModelling and Control in Biomedical Systems, Aalborg, Denmark, August 12-14, 2009. - : IFAC Secretariat. - 9783902661494 ; , s. 210-215
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Konferensbidrag (refereegranskat)abstract
- Because of the overlapping of the spectra of different metabolites and the interference of the baseline mainly from broad resonances of macromolecule and lipids, it is difficult to achieve the quantification of spectra of different metabolites which is important for both research and clinical applications of Magnetic Resonance Spectroscopy (MRS). In this paper, a novel MRS quantification method based on frequency a priori knowledge is proposed. Firstly, a wavelet filter is used to remove the broad components of an observed spectrum in which baseline and the relatively broad components of metabolite spectrum are included. Secondly, a linear nonnegative pursuit algorithm based on regularized FOCUSS (Focal Underdetermined System Solver) algorithm is used to decompose the filtered spectra in a dictionary which is based on a set of Lorentzian and Gaussian functions corresponding to spectrum models. Benefitting from the a priori knowledge of the peak frequency of each metabolite, the filtered metabolite spectrum can be sparsely represented with these basis functions and the spectra of different metabolites are relevant to certain basis functions. Therefore, with the corresponding relation between the basis functions and spectrum models and the estimated decomposition coefficients, a mixed spectrum without baseline can be reconstructed and spectra of different metabolites can be quantified at the same time. The accuracy and the robustness of MRS quantification are improved by the proposed method, from simulation data, compared with commonly used MRS quantification methods. Quantification on in vivo brain spectra is also demonstrated.
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| 5680. |
- Guo, Yu, et al.
(författare)
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A priori knowledge based frequency-domain quantification of prostate Magnetic Resonance Spectroscopy
- 2011
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Ingår i: Biomedical Signal Processing and Control. - : Elsevier. - 1746-8094 .- 1746-8108. ; 6:1, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a frequency-domain Magnetic Resonance (MR) spectral processing method based on sparse representation for accurate quantification of prostate spectra. Generally, an observed prostate spectrum can be considered as a mixture of resonances of interest, a baseline and noise. As the resonances of interest often overlap and the baseline is unknown, their separation and quantification can be difficult. In the proposed method, based on the commonly used signal model of prostate spectra and some a priori knowledge of nonlinear model parameters, a dictionary is constructed which can sparsely represent the resonances of interest as well as the baseline in an input spectrum. The estimation of the resonances of interest is achieved by finding their sparse representations with respect this dictionary. A linear pursuit algorithm based on regularized FOCUSS (Focal Underdetermined System Solver) algorithm is proposed to estimate these sparse representations. The robustness and accuracy of prostate spectrum quantification of the proposed method are improved compared with two classical spectral processing methods: model-based time domain fitting and frequency-domain analysis based on peak integration when tested on simulation data. Quantification on in vivo prostate spectra is also demonstrated and the results appear encouraging.
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