182 research outputs found

    FEPSAC International Congress: Sport Psychology – Theories and Applications for Performance, Health and Humanity: A doctoral student’s reflection

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    Recently there has been renewed interest in basing teachers’ professional learning on medically derived models. This interest has included clinical practice models and evidencebased teaching as well as the use of various forms of ‘Rounds’ which claim to derive from medical rounds. However, many arguing for these approaches may not have a detailed knowledge of the actuality of professional learning in medicine but may be basing their ideas on idealised models drawn from popular conceptions. In addition, the model used by some calling for medically derived teacher learning is biomedicine, an area in which parallels with Education are difficult. This paper argues that mental health and public health provide a better analogue for Education than biomedicine. It considers some of the lessons that can be drawn from research on evidence-based practice in these areas. The paper concludes that a way forward is neither uncritically to assume the superiority of medical models of professional learning nor to rely only on empirical evidence from Education but to enter into dialogue with colleagues in mental and public health about shared concerns and experiences in professional learning

    Forces between electric charges in motion: Rutherford scattering, circular Keplerian orbits, action-at-a-distance and Newton's third law in relativistic classical electrodynamics

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    Standard formulae of classical electromagnetism for the forces between electric charges in motion derived from retarded potentials are compared with those obtained from a recently developed relativistic classical electrodynamic theory with an instantaneous inter-charge force. Problems discussed include small angle Rutherford scattering, Jackson's recent `torque paradox' and circular Keplerian orbits. Results consistent with special relativity are obtained only with an instantaneous interaction. The impossiblity of stable circular motion with retarded fields in either classical electromagnetism or Newtonian gravitation is demonstrated.Comment: 26 pages, 5 figures. QED and special relativity forbid retarded electromagnetic forces. See also physics/0501130. V2 has typos corrected, minor text modifications and updated references. V3 has further typos removed and added text and reference

    Commonly used indices disagree about the effect of moisture on heat stress

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    Irrigation and urban greening can mitigate extreme temperatures and reduce adverse health impacts from heat. However, some recent studies suggest these interventions could actually exacerbate heat stress by increasing humidity. These studies use different heat stress indices (HSIs), hindering intercomparisons of the relative roles of temperature and humidity. Our method uses calculus of variations to compare the sensitivity of HSIs to temperature and humidity, independent of HSI units. We explain the properties of different HSIs and identify conditions under which they disagree. We highlight recent studies where the use of different HSIs could have led to opposite conclusions. Our findings have significant implications for the evaluation of irrigation and urban greening as adaptive responses to overheating and climate adaptation measures in general. We urge researchers to be critical in their choice of HSIs, especially in relation to health outcomes; our method provides a useful tool for making informed comparisons

    Non-Relativistic Limit of Dirac Equations in Gravitational Field and Quantum Effects of Gravity

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    Based on unified theory of electromagnetic interactions and gravitational interactions, the non-relativistic limit of the equation of motion of a charged Dirac particle in gravitational field is studied. From the Schrodinger equation obtained from this non-relativistic limit, we could see that the classical Newtonian gravitational potential appears as a part of the potential in the Schrodinger equation, which can explain the gravitational phase effects found in COW experiments. And because of this Newtonian gravitational potential, a quantum particle in earth's gravitational field may form a gravitationally bound quantized state, which had already been detected in experiments. Three different kinds of phase effects related to gravitational interactions are discussed in this paper, and these phase effects should be observable in some astrophysical processes. Besides, there exists direct coupling between gravitomagnetic field and quantum spin, radiation caused by this coupling can be used to directly determine the gravitomagnetic field on the surface of a star.Comment: 12 pages, no figur

    Rotation of electromagnetic fields and the nature of optical angular momentum

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    The association of spin and orbital angular momenta of light with its polarization and helical phase fronts is now well established. The problems in linking this with electromagnetic theory, as expressed in Maxwell's equations, are rather less well known. We present a simple analysis of the problems involved in defining spin and orbital angular momenta for electromagnetic fields and discuss some of the remaining challenges. Crucial to our investigation is the duplex symmetry between the electric and magnetic fields

    Angular momentum effects in weak gravitational fields

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    It is shown that, contrary to what is normally expected, it is possible to have angular momentum effects on the geometry of space time at the laboratory scale, much bigger than the purely Newtonian effects. This is due to the fact that the ratio between the angular momentum of a body and its mass, expressed as a length, is easily greater than the mass itself, again expressed as a length.Comment: LATEX, 8 page

    Multiple air pollutants and their health impacts for both present-day and future scenarios

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    The adverse health impacts of air pollution, both short-term and long-term, have been widely studied in recent years; however there are a number of uncertainties to consider when carrying out health impact assessments. Health effects attributable to exposure to air pollutants are typically estimated using measured or modelled pollutant concentrations which vary both temporally and spatially. The goal of this thesis is to perform health impact assessments using modelled pollutant concentrations for present-day and future. The specific aims are: (i) to study the influence of model horizontal resolution on simulated concentrations of ozone (O3) and particulate matter less than 2.5 μm in diameter (PM2.5) for Europe and the implications for health impact assessments associated with long-term exposure (ii) to model air pollutant concentrations during two air pollution episodes in July 2006 together with the corresponding short-term health impact in the UK (iii) to estimate potential future health burdens associated with long-term pollutant exposure under future UK emission changes for 2050 in the UK. First, the impact of model horizontal resolution on simulated concentrations of O3 and PM2.5, and on the associated long-term health impacts over Europe is examined, using the HadGEM3–UKCA (UK Chemistry and Aerosol) chemistry– climate model to simulate pollutant concentrations at a coarse (~140 km) and a finer (~50 km) horizontal resolution. The attributable fraction (AF) of total mortality due to long-term exposure to warm season daily maximum 8-hr running mean (MDA8) O3 and annual-mean PM2.5 concentrations is then estimated for each European country using pollutant concentrations simulated at each resolution. Results highlight seasonal variations in simulated O3 and PM2.5 differences between the two model resolutions in Europe. Simulated O3 concentrations averaged for Europe at the coarse resolution are higher in winter and spring (~10 and ~6 %, respectively) but lower in summer and autumn (~-1 and ~-4 %, respectively) compared to the finer resolution results. These differences may be partly explained by differences in nitrogen dioxide (NO2) concentrations simulated at the two resolutions. Compared to O3, the opposite seasonality in simulated PM2.5 differences between the two resolutions is found. In winter and spring, simulated PM2.5 concentrations are lower at the coarse compared to the finer resolution (~-8 and ~-6 % averaged for Europe, respectively) but higher in summer and autumn (~29 and ~8 %, respectively). Differences in simulated PM2.5 levels are largely related to differences in convective rainfall and boundary layer height between the two resolutions for all seasons. These differences between the two resolutions exhibit clear spatial patterns for both pollutants that vary by season, and exert a strong influence on country to country variations in the estimated AF of mortality for the two resolutions. Results demonstrate that health impact assessments calculated using modelled pollutant concentrations, are sensitive to a change in model resolution with differences in AF of mortality between the countries ranging between ~-5% and ~+3%. Under climate change, the risk of extreme weather events, such as heatwaves, is likely to increase. Thus the UK health burden associated with short-term exposure to MDA8 O3 and daily mean PM2.5 is examined during two five-day air pollution episodes during a well-known heatwave period in July 2006 (1st - 5th July and 18th – 22nd July) using the UK Met Office air quality model (AQUM) at 12 km horizontal resolution. Both episodes are found to be driven by anticyclonic conditions (mean sea-level pressures ~1020hPa over the UK) with light easterly and south easterly winds and high temperatures that aided pollution build up in the UK. The estimated total mortality burden associated with short-term exposure to O3 is similar during the each episode with about 70 daily deaths brought forward summed across the UK. The estimated health burden associated with short-term exposure to daily mean PM2.5 concentrations differs between the first and second episode resulting in about 43 and 36 daily deaths brought forward, respectively. The attributable fraction of all-cause (excluding external) mortality for both pollutants differs between UK regions and ranges between 1.6% to 5.2% depending on the pollution levels in each episode; the overall total estimated health burdens are highest in regions with higher population totals. Results show that during these episodes, short-term exposure to MDA8 O3 and daily mean PM2.5 is between 36- 38% and 39-56% higher, respectively, than if the pollution levels represented typical seasonal-mean concentrations. Finally, emission scenarios for the UK following three Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCPs); RCP2.6, RCP6.0 and RCP8.5 are used to simulate future concentrations of O3, NO2 and PM2.5 for 2050 relative to 2000 using the AQUM air quality model at 12km resolution. The present-day and future AF of mortality associated with long-term exposure to annual mean MDA8 O3, NO2 and PM2.5 and the corresponding mortality burdens are estimated for each region in the UK. For all three RCPs, simulated annual mean MDA8 O3 concentrations in 2050 are estimated to increase compared to 2000, due to decreases in nitrogen oxides (NOx) emissions reducing titration of O3 by NO, and to increases in methane (CH4) levels across all of the UK. In contrast, annual mean NO2 concentrations decrease everywhere. This highlights that the whole of the UK is simulated to be in a NOx-saturated chemical environment. PM2.5 concentrations decrease under all RCPs for the 2050s mostly driven by decreases in NOx and sulphur dioxide (SO2) emissions affecting secondary inorganic aerosols concentrations. For all pollutants the largest changes are estimated under RCP8.5 while the smallest changes are estimated for RCP6.0 in 2050 as compared to present-day. Consequently, these two RCPs represent the high and low end of the AF and mortality burden difference range relative to present-day for all three pollutants. For all UK regions and all three RCPs, the AF of mortality associated with long-term exposure to O3 is estimated to increase in 2050 while the AF associated with long-term exposure to NO2 and PM2.5 is estimated to decrease as a result of higher and lower projected pollutant concentrations, respectively. Differences in the UK-wide mortality burden attributable to long-term exposure to annual mean MDA8 O3 across the RCPs range from +2,529 to +5,396 additional attributable deaths in 2050 compared to 2000. Long-term exposure to annual mean NO2 and PM2.5 differences in health burdens are between - 9,418 and -15,782 and from - 4,524 to -9,481 avoided attributable deaths in 2050 relative to present-day, respectively. These mortality burdens are also sensitive to future population projections. These results demonstrate that long-term health impact assessments estimated using modelled pollutant concentrations, are sensitive to a change in model resolution across Europe, especially in southern and eastern Europe. In addition, air pollution episodes are shown to have the potential to cause substantial short-term impacts on public health in the UK. Finally the sensitivity of future MDA8 O3-, NO2- and PM2.5-attributable health burdens in the UK to future emission scenarios as well as population projections is highlighted with implications for informing future emissions control strategies for the UK

    An open-source automatic survey of green roofs in London using segmentation of aerial imagery

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    Green roofs can mitigate heat, increase biodiversity, and attenuate storm water, giving some of the benefits of natural vegetation in an urban context where ground space is scarce. To guide the design of more sustainable and climate-resilient buildings and neighbourhoods, there is a need to assess the existing status of green roof coverage and explore the potential for future implementation. Therefore, accurate information on the prevalence and characteristics of existing green roofs is needed, but this information is currently lacking. Segmentation algorithms have been used widely to identify buildings and land cover in aerial imagery. Using a machine learning algorithm based on U-Net (Ronneberger et al., 2015) to segment aerial imagery, we surveyed the area and coverage of green roofs in London, producing a geospatial dataset (https://doi.org/10.5281/zenodo.7603123, Simpson et al., 2023). We estimate that there was 0.23 km2 of green roof in the Central Activities Zone (CAZ) of London, 1.07 km2 in Inner London, and 1.89 km2 in Greater London in the year 2021. This corresponds to 2.0 % of the total building footprint area in the CAZ and 1.3 % in Inner London. There is a relatively higher concentration of green roofs in the City of London, covering 3.9 % of the total building footprint area. Test set accuracy was 0.99, with an F score of 0.58. When tested against imagery and labels from a different year (2019), the model performed just as well as a model trained on the imagery and labels from that year, showing that the model generalised well between different imagery. We improve on previous studies by including more negative examples in the training data and by requiring coincidence between vector building footprints and green roof patches. We experimented with different data augmentation methods and found a small improvement in performance when applying random elastic deformations, colour shifts, gamma adjustments, and rotations to the imagery. The survey covers 1558 km2 of Greater London, making this the largest open automatic survey of green roofs in any city. The geospatial dataset is at the single-building level, providing a higher level of detail over the larger area compared to what was already available. This dataset will enable future work exploring the potential of green roofs in London and on urban climate modelling.</p

    Examples of the Zeroth Theorem of the History of Physics

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    The zeroth theorem of the history of science (enunciated by E. P. Fischer) and widely known in the mathematics community as Arnol'd's Principle (decreed by M. V. Berry), states that a discovery (rule, regularity, insight) named after someone (often) did not originate with that person. I present five examples from physics: the Lorentz condition defining the Lorentz gauge of the electromagnetic potentials; the Dirac delta function (x); the Schumann resonances of the earth-ionosphere cavity; the Weizsacker-Williams method of virtual quanta; the BMT equation of spin dynamics. I give illustrated thumbnail sketches of both the true and reputed discoverers and quote from their "discovery" publications.Comment: 36 pages, 8 figures. Small revisions, added material and references - Arnol'd's law, Emil Wiechert. Submitted to Am. J. Phy
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