443 research outputs found

    Fractal geometry of critical Potts clusters

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    Numerical simulations on the total mass, the numbers of bonds on the hull, external perimeter, singly connected bonds and gates into large fjords of the Fortuin-Kasteleyn clusters for two-dimensional q-state Potts models at criticality are presented. The data are found consistent with the recently derived corrections-to-scaling theory. However, the approach to the asymptotic region is slow, and the present range of the data does not allow a unique identification of the exact correction exponentsComment: 7 pages, 8 figures, Late

    Studies Needed to Address Public Health Challenges of the 2009 H1N1 Influenza Pandemic: Insights from Modeling

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    In light of the 2009 influenza pandemic and potential future pandemics, Maria Van Kerkhove and colleagues anticipate six public health challenges and the data needed to support sound public health decision making.The authors acknowledge support from the Bill & Melinda Gates Foundation (MDVK, CF, NMF); Royal Society (CF); Medical Research Council (MDVK, CF, PJW, NMF); EU FP7 programme (NMF); UK Health Protection Agency (PJW); US National Institutes of Health Models of Infectious Disease Agent Study program through cooperative agreement 1U54GM088588 (ML); NIH Director's Pioneer Award, DP1-OD000490-01 (DS); EU FP7 grant EMPERIE 223498 (DS); the Wellcome Trust (DS); 3R01TW008246-01S1 from Fogerty International Center and RAPIDD program from Fogerty International Center with the Science & Technology Directorate, Department of Homeland Security (SR); and the Institut de Veille Sanitaire Sanitaire funded by the French Ministry of Health (J-CD). The funders played no role in the decision to submit the article or in its preparation

    Motion of flux transfer events: a test of the Cooling model

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    The simple model of reconnected field line motion developed by Cooling et al. (2001) has been used in several recent case studies to explain the motion of flux transfer events across the magnetopause. We examine 213 FTEs observed by all four Cluster spacecraft under a variety of IMF conditions between November 2002 and June 2003, when the spacecraft tetrahedron separation was ~5000 km. Observed velocities were calculated from multi-spacecraft timing analysis, and compared with the velocities predicted by the Cooling model in order to check the validity of the model. After excluding three categories of FTEs (events with poorly defined velocities, a significant velocity component out of the magnetopause surface, or a scale size of less than 5000 km), we were left with a sample of 118 events. 78% of these events were consistent in both direction of motion and speed with one of the two model de Hoffmann-Teller (dHT) velocities calculated from the Cooling model (to within 30° and a factor of two in the speed). We also examined the plasma signatures of several magnetosheath FTEs; the electron signatures confirm the hemisphere of connection indicated by the model in most cases. This indicates that although the model is a simple one, it is a useful tool for identifying the source regions of FTEs

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    Public health impacts of city policies to reduce climate change:Findings from the URGENCHE EU-China project

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    Background: Climate change is a global threat to health and wellbeing. Here we provide findings of an international research project investigating the health and wellbeing impacts of policies to reduce greenhouse gas emissions in urban environments.Methods: Five European and two Chinese city authorities and partner academic organisations formed the project consortium. The methodology involved modelling the impact of adopted urban climate-change mitigation transport, buildings and energy policy scenarios, usually for the year 2020 and comparing them with business as usual (BAU) scenarios (where policies had not been adopted). Carbon dioxide emissions, health impacting exposures (air pollution, noise and physical activity), health (cardiovascular, respiratory, cancer and leukaemia) and wellbeing (including noise related wellbeing, overall wellbeing, economic wellbeing and inequalities) were modelled. The scenarios were developed from corresponding known levels in 2010 and pre-existing exposure response functions. Additionally there were literature reviews, three longitudinal observational studies and two cross sectional surveys.Results: There are four key findings. Firstly introduction of electric cars may confer some small health benefits but it would be unwise for a city to invest in electric vehicles unless their power generation fuel mix generates fewer emissions than petrol and diesel. Second, adopting policies to reduce private car use may have benefits for carbon dioxide reduction and positive health impacts through reduced noise and increased physical activity. Third, the benefits of carbon dioxide reduction from increasing housing efficiency are likely to be minor and co-benefits for health and wellbeing are dependent on good air exchange. Fourthly, although heating dwellings by in-home biomass burning may reduce carbon dioxide emissions, consequences for health and wellbeing were negative with the technology in use in the cities studied.Conclusions: The climate-change reduction policies reduced CO2 emissions (the most common greenhouse gas) from cities but impact on global emissions of CO2 would be more limited due to some displacement of emissions. The health and wellbeing impacts varied and were often limited reflecting existing relatively high quality of life and environmental standards in most of the participating cities; the greatest potential for future health benefit occurs in less developed or developing countries.</p

    Verkostonalyysiä soveltamalla voidaan tutkia kuinka opettajaopiskelijat näkevät yhteydet opetttajantiedon osa-alueiden välillä

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    In this article we present a new approach to investigating teacher knowledge. The essay data related to Finnish future teachers' (N = 18) perceptions of the "knowledge required for teaching mathematics" were transformed into a network. We classified the knowledge topics using the Mathematical Knowledge for Teaching (MKT) framework and examined the relationships between the issues raised with the aid of network analysis. According to the results, the future teachers see the six MKT domains in a hierarchical sequence. As it is not subject specific, this approach is also applicable in the investigation of teacher knowledge of other subjects. (C) 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Teachers and their Educators - Views on Contents and their Development Needs in Mathematics Teacher Education

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    Finland has scored well in international assessments (e.g. PISA, TIMSS), and the pressure to attain excellent scores has activated a drive toward even more effective mathematics teacher education. This article presents the results of a qualitative assessment of the mathematics teacher education provided by the University of Eastern Finland. In this study, the views held by practicing teachers (N=101) and teacher educators (N=19) are compared so that the outstanding development needs of mathematics teacher education in terms of their contents can be revealed. The data was gathered via an electronic survey and was mainly analyzed using data-driven methods. In addition, framework provided by Mathematical Knowledge for Teaching (MKT) was used to categorize the respondents’ views regarding the contents of mathematics teacher education and to develop general guidelines for the reform of mathematics teacher education. The results indicate that mathematics teacher education should include pure mathematical content (Common Content Knowledge, CCK) and mathematical content that will have been designed only for future teachers (Specialized Content Knowledge, SCK). Teacher educators and practicing teachers both held the view that the relevance of CCK studies depend on the connections between university and school mathematics. Pedagogical studies should also be reformed because practicing teachers have realized that effective teaching (Knowledge of Content and Teaching, KCT) requires knowledge about learning mathematics (Knowledge of Content and Students, KCS) that is not offered in the current educational system on a sufficiently broad basis. In this study, suggestions for developing mathematics teacher education were mostly connected to four domains of MKT: (CCK, SCK, KCT and KCS). Interestingly those domains are the same domains which has been empirically tested and better conceptualized

    Exposure to electronic media was negatively associated with speech and language development at 18 and 24 months

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    Aim: This study evaluated early speech and language development at 18 and 24 months, and associated factors, based on parental reports. Method: We followed up the CHILD-SLEEP birth cohort of 1667 Finnish-speaking families, who were randomly recruited in 2011–2013 during routine visits to maternity clinics in the Pirkanmaa Hospital District of Finland. The women were approximately 32 weeks’ pregnant at enrolment. Parents reported the size of their child's expressive vocabulary, word combinations, intelligibility, finger-pointing and adherence to instructions. A subsample was studied using the Expressive Language subscale of the Bayley Scales of Infant and Toddler Development, Third Edition. Results: The children's vocabulary was smaller than previously reported. At 18 months of age, 68.8% of the 997 children had a vocabulary of 20 words or less and 35.7% used about five words at most. At 24 months, 32.4% of the 822 children had a vocabulary of 50 words or less and 18.4% used about 20 words at most. Longer child and parental exposure to electronic media was negatively associated with the size of the child's expressive vocabulary. Conclusion: Vocabulary size at 18 and 24 months was smaller than previously reported and negatively associated with exposure to electronic media.Aim This study evaluated early speech and language development at 18 and 24 months, and associated factors, based on parental reports. Method We followed up the CHILD-SLEEP birth cohort of 1667 Finnish-speaking families, who were randomly recruited in 2011-2013 during routine visits to maternity clinics in the Pirkanmaa Hospital District of Finland. The women were approximately 32 weeks' pregnant at enrolment. Parents reported the size of their child's expressive vocabulary, word combinations, intelligibility, finger-pointing and adherence to instructions. A subsample was studied using the Expressive Language subscale of the Bayley Scales of Infant and Toddler Development, Third Edition. Results The children's vocabulary was smaller than previously reported. At 18 months of age, 68.8% of the 997 children had a vocabulary of 20 words or less and 35.7% used about five words at most. At 24 months, 32.4% of the 822 children had a vocabulary of 50 words or less and 18.4% used about 20 words at most. Longer child and parental exposure to electronic media was negatively associated with the size of the child's expressive vocabulary. Conclusion Vocabulary size at 18 and 24 months was smaller than previously reported and negatively associated with exposure to electronic media.Peer reviewe
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