9 research outputs found
Roller coaster loop shapes revisited
No full textIn 'Rollercoaster loop shapes', (Pendrill 2005 Phys. Educ. 40 517) the author started from the observation that although textbook loops are often circular, real rollercoaster loops are not. In this paper the mathematical description of various possible loop shapes, as well as their riding properties was discussed and also how a study of loop shapes can be used in physics education
Roller coaster loop shapes revisited [Elektronisk resurs]
No full textIn 'Rollercoaster loop shapes', (Pendrill 2005 Phys. Educ. 40 517) the author started from the observation that although textbook loops are often circular, real rollercoaster loops are not. In this paper the mathematical description of various possible loop shapes, as well as their riding properties was discussed and also how a study of loop shapes can be used in physics education
Optimised uncertainty and cost operating characteristics : new tools for conformity assessment. Application to geometrical product control in automobile industry
No full textTranslating measurement uncertainty into terms of effective impact associated with manufacture, testing and incorrect assessment gives a more “stakeholder” motivated (and ultimately optimised) approach to decision-making in conformance assessment. Recently developed decision-theory tools include the “optimized uncertainty” methodology and the “operating cost characteristic”. Overall costs, E, consisting of a sum of testing costs, D, and the costs, C, associated with customer risk, where RPV denotes the region of permissible values and s is a measure of dispersion. A complete, 3D surface of overall cost can indicate the optimum level of measurement effort of these two ranges, as recently published by the author in a wide range of applications: optimized acceptance sampling; optimized testing of measurement instruments; and an analysis of optimised calibration intervals and “guard-banding”. This approach is illustrated in the present work for the example of geometrical product control in the car industry, specifically the gap in vehicle closure panels taking account of customer dissatisfaction.</p
Quality assured measurement: unification across social and physical sciences
No full textThis book presents a general and comprehensive framework for the assurance of quality in measurements. Written by a foremost expert in the field, the text reflects an on-going international effort to extend traditional quality assured measurement, rooted in fundamental physics and the SI, to include non-physical areas such as person-centred care and the social sciences more generally. Chapter by chapter, the book follows the measurement quality assurance loop, based on Deming’s work. The author enhances this quality assurance cycle with insights from recent research, including work on the politics and philosophy of metrology, the new SI, quantitative and qualitative scales and entropy, decision risks and uncertainty when addressing human challenges, Man as a Measurement Instrument, and Psychometry and Person-centred care. Quality Assured Measurement: Unification across Social and Physical Sciences provides students and researchers in physics, chemistry, engineering, medicine and the social sciences with practical guidance on designing, implementing and applying a quality-assured measurement while engaging readers in the most novel and expansive areas of contemporary measurement research.
Velocity, acceleration, jerk, snap and vibration: Forces in our bodies during a roller coaster ride
No full text© 2020 The Author(s). Published by IOP Publishing Ltd. Changing acceleration and forces are part of the excitement of a roller coaster ride. According to Newton's second law, F = ma, every part of our body must be exposed to a force to accelerate. Since our bodies are not symmetric, the direction of the force matters, and must be accounted for by ride designers. An additional complication is that not all parts of the body accelerate in the same way when the acceleration is changing, i.e. when there is jerk. Softer parts of the body provide varying levels of damping, and different parts of the body have different frequency responses and different resonance frequencies that should be avoided or reduced by the roller coaster designer. This paper discusses the effect of acceleration, jerk, snap and vibration on the experience and safety of roller coaster rides, using authentic data from a dive coaster as an example
Trends of Physics Education Research on The Topic of Mechanics: A Bibliometric Analysis
No full textThis study aims to map the publication trends of international journal articles related to the topic of mechanics in physics education using bibliometric analysis of the Scopus database. Bibliometric analysis was conducted on the Scopus database with the help of the RStudio application with the biblioshiny package. We analyzed 196 relevant documents filtered with various settings that support the research objectives. The analysis showed a rapid increase in the number of publications on mechanics in physics education since the 2000s (102 articles recorded in 2012–2021), driven by the development of quantitative methods. Physics Education, Physics Teacher, and Revista Brasileira de Ensino de Fisica were the journals with the most contributions. Active author mapping identified Pendrill A-M, Fones SW, and Rieber LP as the most prolific, while citation and h-index analyses showed the work of Rieber LP, Rodrigues H, Adams DM, and Gauld C as the most influential. Geographically, the United States, Brazil, and China dominated publications, with limited international collaboration. This study provided a comprehensive profile of mechanical research trends in physics education to guide future development efforts
Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial
No full textBackground
Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain.
Methods
RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and
ClinicalTrials.gov
,
NCT00541047
.
Findings
Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths.
Interpretation
Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy.
Funding
Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society
Effects on hydrological variables and potential provision of ecosystem services as a result of land cover changes. Case study Socioecological system of the Mira River basin.
No full textilustraciones, mapasEn esta investigación se exploró principalmente los efectos sobre las variables del balance de agua y energía y la provisión potencial de servicios ecosistémicos producto del cambio de cobertura vegetal en la cuenca del río Mira, desde la perspectiva del marco conceptual de los sistemas socio-ecológicos. Para ello, en el primer capítulo se realizó la clasificación y mapeo de coberturas del suelo para la identificación de las características, extensión y patrón de cambio de la cobertura del suelo en el tiempo. Los resultados revelaron que las áreas de pastos, cultivos, suelo desnudo y zonas urbanas aumentaron durante el periodo 1987-2019, lo que resultó en una reducción sustancial de la superficie forestal y los páramos. En el capítulo 3 se analizó la precisión del balance de agua y energía de largo plazo en la cuenca del Río Mira a través de diferentes conjuntos de datos de teledetección e información in situ. La evaluación de la precisión hasta la estación hidrológica más cercana a la desembocadura de la cuenca indicó que el error porcentual entre el caudal de la estación y el caudal obtenido del balance de agua es del orden de 50\%, evidenciándose una subestimación generalizada en los resultados. Además se detectó una tendencia decreciente estadísticamente significativa en el residuo del balance de energía a escala mensual y en el caudal medio mensual de la estación hidrológica, este último con una pendiente de aproximadamente 0.38 m^3/s por mes y un cambio en la homogeneidad de la serie en agosto del año 2000. Además, en el capítulo 4 se exploró la respuesta hidrológica de la cuenca estudiando 27 subcuencas a partir de dos ecuaciones derivadas del marco teórico de Budyko, la ecuación propuesta por Choudhury-Yang y la ecuación de Carmona et al., y usando el método de contribución del cambio de escorrentía basado en la ecuación de Choudhury-Yang se cuantificaron las contribuciones de la fluctuación climática y de uso/cobertura del suelo en el cambio de escorrentía, lo cual evidenció que la contribución del uso/cobertura del suelo es significativo, demostrando la relevancia de la cobertura vegetal en el mantenimiento y regulación de los procesos hidrológicos en la cuenca; también se cuantificó el efecto del cambio de cobertura vegetal en los componentes individuales del balance de energía y en el cambio resultante en la temperatura de la superficie terrestre, obteniéndose variaciones importantes en los componentes del balance energético entre los subperiodos 1981 - 1999 y 2000 – 2018 que se traducen en un aumento generalizado de la temperatura en la zona de estudio. Y finalmente en el capítulo 5, se desarrolló un esquema conceptual de las interrelaciones existentes entre los servicios ecosistémicos, el sistema social y el sistema natural, a través de diagramas causales como una representación conceptual de la complejidad dinámica del sistema. (Tomado de la fuente)This research mainly explores the effects on the variables of the water and energy balance and the potential provision of ecosystem services as a result of the change in vegetation cover in the Mira river basin, from the perspective of the conceptual framework of socio-ecological systems. For this, the basin was characterized and the vegetation covers were classified to understand the characteristics, the extension, and the pattern of the change of the land cover over time. Through the analysis of the water balance and the energy balance, it was contributed to the knowledge of the hydro-climatological processes in the Mira River basin using satellite information and in situ information available the basin, this was performed from the perspective of the characterization of the variables, the closing of the balances and the consideration of other variables that may intervene in the processes. Besides, the hydrological response was explored by studying 27 sub-basins of the Mira river basin from two equations derived from the Budyko theoretical framework, the equation proposed by Choudhury-Yang and the empirical equation proposed by Carmona et al.; The resulting change in surface temperature in the basin was also explored, using the surface energy balance decomposition approach. And finally, a conceptual model of interrelationships between ecosystem services, the social system, and the natural system was developed, through causal loop diagrams as a conceptual representation of the dynamic complexity of the system. (Tomado de la fuente)MaestríaMagíster en Ingeniería - Recursos HidráulicosHidrología y servicios ecosistémico
