Fractal Dimensions in Perceptual Color Space: A Comparison Study Using Jackson Pollock's Art

The fractal dimensions of color-specific paint patterns in various Jackson Pollock paintings are calculated using a filtering process which models perceptual response to color differences (\Lab color space). The advantage of the \Lab space filtering method over traditional RGB spaces is that the former is a perceptually-uniform (metric) space, leading to a more consistent definition of ``perceptually different'' colors. It is determined that the RGB filtering method underestimates the perceived fractal dimension of lighter colored patterns but not of darker ones, if the same selection criteria is applied to each. Implications of the findings to Fechner's 'Principle of the Aesthetic Middle' and Berlyne's work on perception of complexity are discussed.Comment: 21 pp LaTeX; two postscript figure

Materials Design using Correlated Oxides: Optical Properties of Vanadium Dioxide

Materials with strong electronic Coulomb interactions play an increasing role in modern materials applications. "Thermochromic" systems, which exhibit thermally induced changes in their optical response, provide a particularly interesting case. The optical switching associated with the metal-insulator transition of vanadium dioxide (VO2), for example, has been proposed for use in "intelligent" windows, which selectively filter radiative heat in hot weather conditions. In this work, we develop the theoretical tools for describing such a behavior. Using a novel scheme for the calculation of the optical conductivity of correlated materials, we obtain quantitative agreement with experiments for both phases of VO2. On the example of an optimized energy-saving window setup, we further demonstrate that theoretical materials design has now come into reach, even for the particularly challenging class of correlated electron systems.Comment: 4+x pages, 2 figure

The intervention process in the European Fans in Training (EuroFIT) trial: a mixed method protocol for evaluation

Background - EuroFIT is a gender-sensitised, health and lifestyle program targeting physical activity, sedentary time and dietary behaviours in men. The delivery of the program in football clubs, led by the clubs’ community coaches, is designed to both attract and engage men in lifestyle change through an interest in football or loyalty to the club they support. The EuroFIT program will be evaluated in a multicentre pragmatic randomised controlled trial (RCT), for which ~1000 overweight men, aged 30–65 years, will be recruited in 15 top professional football clubs in the Netherlands, Norway, Portugal and the UK. The process evaluation is designed to investigate how implementation within the RCT is achieved in the various football clubs and countries and the processes through which EuroFIT affects outcomes. Methods - This mixed methods evaluation is guided by the Medical Research Council (MRC) guidance for conducting process evaluations of complex interventions. Data will be collected in the intervention arm of the EuroFIT trial through: participant questionnaires (n = 500); attendance sheets and coach logs (n = 360); observations of sessions (n = 30); coach questionnaires (n = 30); usage logs from a novel device for self-monitoring physical activity and non-sedentary behaviour (SitFIT); an app-based game to promote social support for physical activity outside program sessions (MatchFIT); interviews with coaches (n = 15); football club representatives (n = 15); and focus groups with participants (n = 30). Written standard operating procedures are used to ensure quality and consistency in data collection and analysis across the participating countries. Data will be analysed thematically within datasets and overall synthesis of findings will address the processes through which the program is implemented in various countries and clubs and through which it affects outcomes, with careful attention to the context of the football club. Discussion - The process evaluation will provide a comprehensive account of what was necessary to implement the EuroFIT program in professional football clubs within a trial setting and how outcomes were affected by the program. This will allow us to re-appraise the program’s conceptual base, optimise the program for post-trial implementation and roll out, and offer suggestions for the development and implementation of future initiatives to promote health and wellbeing through professional sports clubs. Trial Registration - ISRCTN81935608. Registered on 16 June 2015

A New, Bright, Short-Period, Emission Line Binary in Ophiuchus

The 11th magnitude star LS IV -08 3 has been classified previously as an OB star in the Luminous Stars survey, or alternatively as a hot subdwarf. It is actually a binary star. We present spectroscopy, spectroscopic orbital elements, and time series photometry, from observations made at the Kitt Peak National Observatory 2.1m, Steward Observatory 2.3m, MDM Observatory 1.3m and 2.4m, Hobby-Eberly 9.2m, and Michigan State University 0.6m telescopes. The star exhibits emission of varying strength in the cores of H and He I absorption lines. Emission is also present at 4686 Angstroms (He II) and near 4640/4650 Angstroms (N III/C III). Time-series spectroscopy collected from 2005 July to 2007 June shows coherent, periodic radial velocity variations of the H-alpha line, which we interpret as orbital motion with a period of 0.1952894(10) days. High-resolution spectra show that there are two emission components, one broad and one narrow, moving in antiphase, as might arise from an accretion disk and the irradiated face of the mass donor star. Less coherent, low-amplitude photometric variability is also present on a timescale similar to the orbital period. Diffuse interstellar bands indicate considerable reddening, which however is consistent with a distance of ~100-200 pc. The star is the likely counterpart of a weak ROSAT X-ray source, whose properties are consistent with accretion in a cataclysmic variable (CV) binary system. We classify LS IV -08 3 as a new member of the UX UMa subclass of CV stars.Comment: To be published in AJ, 16 pages, 6 figures. Uses AAS Late

Precision tests with a new class of dedicated ether-drift experiments

In principle, by accepting the idea of a non-zero vacuum energy, the physical vacuum of present particle physics might represent a preferred reference frame. By treating this quantum vacuum as a relativistic medium, the non-zero energy-momentum flow expected in a moving frame should effectively behave as a small thermal gradient and could, in principle, induce a measurable anisotropy of the speed of light in a loosely bound system as a gas. We explore the phenomenological implications of this scenario by considering a new class of dedicated ether-drift experiments where arbitrary gaseous media fill the resonating optical cavities. Our predictions cover most experimental set up and should motivate precise experimental tests of these fundamental issues.Comment: Accepted for publication in Eur. Phys. Journ.

Action 3:30R: Process evaluation of a cluster randomised feasibility study of a revised teaching assistant-led extracurricular physical activity intervention for 8 to 10 year olds

Background: Numerous interventions to increase children's physical activity levels are published, yet, few studies report indicators of external validity. Process evaluations are critical for assessing intervention implementation, sustainability and effectiveness. A mixed-methods process evaluation, using the RE-AIM framework, was conducted to evaluate the internal and external validity of Action 3:30R, a revised teaching assistant-led after-school intervention which aimed to increase physical activity in children aged 8-10 years and was underpinned by Self-determination Theory (SDT). Methods: Data were collected and reported in line with the five components of RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance). Quantitative measures included logbooks, registers and self-reported teaching-efficacy, autonomy support, child enjoyment and perceived exertion questionnaires. Questionnaire data were collected at three points throughout the 15-week intervention. Observations by trained researchers were also conducted to assess fidelity to the intervention manual and its underpinning theory. Post-intervention focus groups with pupils and interviews with teaching assistants (TAs), school staff and external stakeholders explored the implementation and potential sustainability of Action 3:30R from stakeholders' perspectives. Results: Action 3:30R appealed to a broad range of pupils, including girls and less-active pupils. The Action 3:30R TA training was implemented as intended and was perceived as valuable professional development. Releasing staff for training was a barrier in two of the six intervention schools, which were unable to deliver the intervention as a result. Pupils enjoyed the intervention, and the Action 3:30R core principles underpinned by SDT were implemented with high fidelity, as was the intervention itself. Scheduling conflicts with other clubs and lack of parental support were perceived as the main barriers to recruitment and attendance. Lack of space and season were cited as the main barriers affecting the quality of delivery. The study shows evidence of maintenance, as one intervention school decided to continue Action 3:30R beyond the study. Funding and continued TA training were suggested as factors which may affect the maintenance of Action 3:30R. Conclusions: Action 3:30R is an enjoyable, autonomy-supportive after-school programme, which engages a range of pupils and offers TAs valuable training. RE-AIM provided helpful structure and is recommended for intervention evaluations. Trial registration: ISRCTN34001941. Prospectively registered 01/12/2016