271 research outputs found

    Encoding the scaling of the cosmological variables with the Euler Beta function

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    We study the scaling exponents for the expanding isotropic flat cosmological models. The dimension of space, the equation of state of the cosmic fluid and the scaling exponent for a physical variable are related by the Euler Beta function that controls the singular behavior of the global integrals. We encounter dual cosmological scenarios using the properties of the Beta function. For the entropy density integral we reproduce the Fischler-Susskind holographic bound.Comment: Latex2e, 11 pages, 1 figure; reference added; minor changes commenting the nature of the holographic principle and the particle/event horizo

    A literature review of the use of gamification in accounting education

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    [EN] Gamification is a tool that is increasingly used in the field of teaching at all levels of education, from primary to university. Despite the fact that Business Management and Accounting have not remained on the sidelines in studies on the use of game-based learning, the scarcity of such work in this field provides us with only a limited vision of the research that is being carried out in the area. In order to fill this research gap, this paper analyses the academic literature in detail on the use of gamification in accounting education. To this end, an in-depth review of scientific documents retrieved from academic databases has been carried out with the aim of: a) identifying the methodologies used in the research, b) examining the types of games used by researchers, c) establishing the different educational stages where this research is being carried out, d) analysing the samples used, and e) analysing the results obtained in the studies. The results obtained from this review have made it possible to recognise some of the most recurrent work and other research areas in which further exploration can be undertaken within the field of gamification and accounting.Queiro-Ameijieras, CM.; Martí-Parreño, J.; Seguí-Mas, E.; Summerfield, L. (2019). A literature review of the use of gamification in accounting education. IATED. 7662-7667. https://doi.org/10.21125/iceri.2019.1822S7662766

    Radiopurity of Micromegas readout planes

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    Micromesh Gas Amplification Structures (Micromegas) are being used in an increasing number of Particle Physics applications since their conception fourteen years ago. More recently, they are being used or considered as readout of Time Projection Chambers (TPCs) in the field of Rare Event searches (dealing with dark matter, axions or double beta decay). In these experiments, the radiopurity of the detector components and surrounding materials is measured and finely controlled in order to keep the experimental background as low as possible. In the present paper, the first measurement of the radiopurity of Micromegas planes obtained by high purity germanium spectrometry in the low background facilities of the Canfranc Underground Laboratory (LSC) is presented. The obtained results prove that Micromegas readouts of the microbulk type are currently manufactured with radiopurity levels below 30 microBq/cm2 for Th and U chains and ~60 microBq/cm2 for 40K, already comparable to the cleanest detector components of the most stringent low background experiments at present. Taking into account that the studied readouts were manufactured without any specific control of the radiopurity, it should be possible to improve these levels after dedicated development.Comment: 15 pages, 2 figure

    Gaseous time projection chambers for rare event detection: Results from the T-REX project. II. Dark matter

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    As part of the T-REX project, a number of R&D and prototyping activities have been carried out during the last years to explore the applicability of Micromegas-read gaseous TPCs in rare event searches like double beta decay (DBD), axion research and low-mass WIMP searches. While in the companion paper we focus on DBD, in this paper we focus on the results regarding the search for dark matter candidates, both axions and WIMPs. Small ultra-low background Micromegas detectors are used to image the x-ray signal expected in axion helioscopes like CAST at CERN. Background levels as low as 0.8×1060.8\times 10^{-6} c keV1^{-1}cm2^{-2}s1^{-1} have already been achieved in CAST while values down to 107\sim10^{-7} c keV1^{-1}cm2^{-2}s1^{-1} have been obtained in a test bench placed underground in the Laboratorio Subterr\'aneo de Canfranc. Prospects to consolidate and further reduce these values down to 108\sim10^{-8} c keV1^{-1}cm2^{-2}s1^{-1}will be described. Such detectors, placed at the focal point of x-ray telescopes in the future IAXO experiment, would allow for 105^5 better signal-to-noise ratio than CAST, and search for solar axions with gaγg_{a\gamma} down to few 1012^{12} GeV1^{-1}, well into unexplored axion parameter space. In addition, a scaled-up version of these TPCs, properly shielded and placed underground, can be competitive in the search for low-mass WIMPs. The TREX-DM prototype, with \sim0.300 kg of Ar at 10 bar, or alternatively \sim0.160 kg of Ne at 10 bar, and energy threshold well below 1 keV, has been built to test this concept. We will describe the main technical solutions developed, as well as the results from the commissioning phase on surface. The anticipated sensitivity of this technique might reach 1044\sim10^{-44} cm2^2 for low mass (<10<10 GeV) WIMPs, well beyond current experimental limits in this mass range.Comment: Published in JCAP. New version with erratum incorporated (new figure 14

    Runner’s Profile and Propensity to Sports Injury

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    Se evalúa las relaciones entre el perfil sociodemográfico, la accidentabilidad y la propensión al accidente de los participantes en tres eventos deportivos: Zurich Marató de Barcelona, Cros de Muntanya Can Caralleu, y Marató Borredà-Xtrail. Una adaptación del cuestionario de propensión al accidente deportivo (PAD-22) de Latorre y Pantoja (2013) fue administrado a un total de 237 corredores. Los principales resultados muestran que: los corredores tienden a ser mayoritariamente varones, de entre 30 y 46 años, asalariados, con estudios postobligatorios, con experiencia previa en eventos de larga distancia, entrenan una media de 4 veces y un total de 7 horas a la semana; y los corredores de la maratón por asfalto tienen una sobreestimación de la Competencia Percibida y grados de Competitividad mayores a los corredores por montañaThis study evaluates relations between sociodemographic profile, accident rate and accident’s propensity of three sport events participants: Zurich Marató de Barcelona, Cros de Muntanya Can Caralleu & Marató Borredà-Xtrail. The used method was an adaptation of the sports accident prone scale (PAD-22) from Latorre y Pantoja (2013), to 237 runners. The main results show that: runners tend to be mostly men, aged of 30-46 years, are salaried, have post-compulsory studies, have some experience in long distance events, train a mean of 4 times and more than 7 hours per week; and marathon asphalt runners have a overestimation of Perceived Competence and elevated degrees of Competitiveness, more than trail runnersEste trabajo forma parte del Proyecto de Investigación, con código 2014 PINEF 00006 y ha sido realizado con el apoyo del programa de becas predoctorales del Instituto Nacional de Educación Física de Cataluña (PINEFC-2015). Agradecemos el apoyo dado por el INEFC en la realización de este estudio, puesto que, sin su cobijo, no se hubiera podido llevar a cabo con las mismas condicione

    Impaired hypoglycaemia awareness in early pregnancy increases risk of severe hypoglycaemia in the mid-long term postpartum irrespective of breastfeeding status in women with type 1 diabetes

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    Information regarding the postpartum period in women with type 1 diabetes (T1D) is scarce. We aim to evaluate the relation of impaired hypoglycaemia awareness (IAH) in early pregnancy and breastfeeding status (its presence and duration) with severe postpartum hypoglycaemia (SH).Retrospective cohort study of women with T1D followed during pregnancy between 2012 and 2019. Data on SH were recorded before and during pregnancy. IAH was evaluated at the first antenatal visit. Data on breastfeeding and the long-term postpartum period were collected by questionnaire and from medical records.A total of 89 women with T1D were included with a median follow-up after pregnancy of 19.2 [8.7-30.5] months. Twenty-eight (32%) women had IAH at the first antenatal visit. At discharge, 74 (83%) started breastfeeding during a median of 8 [4.4-15] months. A total of 18 (22%) women experienced ≥1 SH during postpartum. The incidence of SH significantly increased from pregestational to the gestational and post-partum period (0.09, 0.15 and 0.25 episodes/patient-year, respectively). Postpartum SH rates were comparable in breastfeeding and non-breastfeeding women (21.4% vs. 25%, respectively, p>0.05). Clarke test score at the first antenatal visit was associated with postpartum SH (for each 1-point increase: OR 1.53; 95% CI, 1.06-2.21) adjusted for confounders. No other diabetes and pregnancy-related variables were identified as predictors of SH in this period.SH are common in the long-term postpartum period independently of breastfeeding. Assessing IAH in early pregnancy could identify those at an increased risk of SH in the postpartum period.Copyright © 2022 SEEN and SED. Published by Elsevier España, S.L.U. All rights reserved

    CAST microbulk micromegas in the Canfranc Underground Laboratory

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    During the last taking data campaigns of the CAST experiment, the micromegas detectors have achieved background levels of 5×106\approx 5 \times 10^{-6}keV1^{-1}cm2^{-2}s1^{-1} between 2 and 9 keV. This performance has been possible thanks to the introduction of the microbulk technology, the implementation of a shielding and the development of discrimination algorithms. It has motivated new studies towards a deeper understanding of CAST detectors background. One of the working lines includes the construction of a replica of the set-up used in CAST by micromegas detectors and its installation in the Canfranc Underground Laboratory. Thanks to the comparison between the performance of the detectors underground and at surface, shielding upgrades, etc, different contributions to the detectors background have been evaluated. In particular, an upper limit <2×107< 2 \times 10^{-7}keV1^{-1}cm2^{-2}s1^{-1} for the intrinsic background of the detector has been obtained. This work means a first evaluation of the potential of the newest micromegas technology in an underground laboratory, the most suitable environment for Rare Event Searches.Comment: 6 pages, 8 figures. To appear in the proceedings of the 2nd International Conference on Technology and Instrumentation for Particle Physics (TIPP 2011

    Inconsistencies in Guidelines for Visual Health Surveillance of VDT Workers

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    Objectives: In Europe, 25% of workers use video display terminals (VDTs). Occupational health surveillance has been considered a key element in the protection of these workers. Nevertheless, it is unclear if guidelines available for this purpose, based on EU standards and available evidence, meet currently accepted quality criteria. The aim of this study was to appraise three sets of European VDT guidelines (UK, France, Spain) in which regulatory and evidence-based approaches for visual health have been formulated and recommendations for practice made. Methods: Three independent appraisers used an adapted AGREE instrument with seven domains to appraise the guidelines. A modified nominal group technique approach was used in two consecutive phases: first, individual evaluation of the three guidelines simultaneously, and second, a face-to-face meeting of appraisers to discuss scoring. Analysis of ratings obtained in each domain and variability among appraisers was undertaken (correlation and kappa coefficients). Results: All guidelines had low domain scores. The domain evaluated most highly was Scope and purpose, while Applicability was scored minimally. The UK guidelines had the highest overall score, and the Spanish ones had the lowest. The analysis of reliability and differences between scores in each domain showed a high level of agreement. Conclusions: These results suggest current guidelines used in these countries need an update. The formulation of evidence-base European guidelines on VDT could help to reduce the significant variation of national guidelines, which may have an impact on practical application.This study was supported by the National Institute for Occupational Safety and Health at Work of the Spanish Work and Immigration Ministry (INSHT). Project reference: 606/UAL/PVDVIS

    Hologrphy and holographic dark energy model

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    The holographic principle is used to discuss the holographic dark energy model. We find that the Bekenstein-Hawking entropy bound is far from saturation under certain conditions. A more general constraint on the parameter of the holographic dark energy model is also derived.Comment: no figures, use revtex, v2: use iop style, some typos corrected and references updated, will appear in CQ
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