Predicting centre of mass horizontal speed in low to severe swimming intensities with linear and non-linear models     

Kelly de Jesus  Helon Vicente Hultmann Ayala  Leandro dos Santos Coelho  João Paulo Vilas-Boas  Ricardo Jorge Pinto Fernandes 《Journal of sports sciences》2019,37(13):1512-1520

We aimed to compare multilayer perceptron (MLP) neural networks, radial basis function neural networks (RBF) and linear models (LM) accuracy to predict the centre of mass (CM) horizontal speed at low-moderate, heavy and severe swimming intensities using physiological and biomechanical dataset. Ten trained male swimmers completed a 7 × 200 m front crawl protocol (0.05 m.s^?1 increments and 30 s intervals) to assess expiratory gases and blood lactate concentrations. Two surface and four underwater cameras recorded independent images subsequently processed focusing a three-dimensional reconstruction of two upper limb cycles at 25 and 175 m laps. Eight physiological and 13 biomechanical variables were inputted to predict CM horizontal speed. MLP, RBF and LM were implemented with the Levenberg-Marquardt algorithm (feed forward with a six-neuron hidden layer), orthogonal least squares algorithm and decomposition of matrices. MLP revealed higher prediction error than LM at low-moderate intensity (2.43 ± 1.44 and 1.67 ± 0.60%), MLP and RBF depicted lower mean absolute percentage errors than LM at heavy intensity (2.45 ± 1.61, 1.82 ± 0.92 and 3.72 ± 1.67%) and RBF neural networks registered lower errors than MLP and LM at severe intensity (2.78 ± 0.96, 3.89 ± 1.78 and 4.47 ± 2.36%). Artificial neural networks are suitable for speed model-fit at heavy and severe swimming intensities when considering physiological and biomechanical background.  相似文献   

Menstrual cycle alters training strain,monotony, and technical training length in young     

Gislaine Cristina-Souza  Ana C. Santos-Mariano  Carla C. Souza-Rodrigues  Raul Osiecki  Sandro F. Silva  Adriano E. Lima-Silva 《Journal of sports sciences》2019,37(16):1824-1830

The menstrual cycle (MC) phases carry to several psychophysiological alterations; however, no study has investigated the impact of MC phases on training load or technical training. In the present study, we investigated the effect of the follicular phase (FP), ovulatory phase (OP), and luteal phase (LP) on training load and technical training in young athletes. Twelve female athletes performed regular daily training sessions with the rating of perceived exertion (RPE) and duration being registered every session. Training impulse (TRIMP), monotony and strain were calculated. MC symptoms, RPE, and duration were also measured during technical training, which was carried out on a specific day during each phase. The TRIMP was not affected by MC phases during regular training (p > .05), but training monotony and strain were higher in FP compared to OP (p < .05). During the technical training, MC phases did not affect RPE (p > .05), but the session was longer in both FP and LP, compared to OP (p < .05). MC symptoms were exacerbated in FP compared to both OP and LP (p < .05). These findings suggest that MC disorders were elevated during FP, which indicate that monitoring MC phases might provide important feedbacks for programming training and expected results during competitions.  相似文献   

Critic power or star power? The influence of hallmarks of quality of motion pictures: an experimental approach     

Ana Suárez-Vázquez 《Journal of Cultural Economics》2011,35(2):119-135

Most research into the film industry focuses on aggregate level market analysis of a range of devices used by the industry to ensure the success of its films. In contrast, in this paper, we experimentally test how individual cinema-goers are influenced by two variables that have aroused considerable interest in the literature: critical reviews and the role of box office stars. As regards the former, the results of our experiment indicate that negative reviews by film critics are cues that affect cinema-goers’ pre-film assessment of a film yet fail to exert any effect on post-film assessment. As regards the latter, a cast of box office stars is not seen to be an indication of quality per se for our experimental subjects. Nor do box office stars help to mitigate the potential effects of negative reviews.  相似文献   

Microscopic and spectroscopic techniques for the study of paper supports and textile used in the binding of hispano-arabic manuscripts from Al-Andalus: A transition model in the 15th century     

Teresa Espejo  Adrian Duran  Ana Lopez-Montes  Rosario Blanc 《Journal of Cultural Heritage》2010,11(1):50-58

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‘Bloomers’ and the British World: Dress Reform in Transatlantic and Antipodean Print Culture, 1851–1950     

Ana Stevenson 《Cultural and Social History》2017,14(5):621-646

The ‘bloomers’ are rarely considered beyond their 1851 origins in the United States and subsequent appearance in Britain. This article expands dress reform scholarship by analysing print culture elsewhere in the British world, specifically Australia and New Zealand. The colonial press manufactured controversy over this fashion – a perceived transgression of gender norms – even though antipodean women rarely sported the outfit. This article focuses on the dress reform lectures and writings of Amelia Bloomer, Caroline Dexter and Dr Mary Walker. While certain continuities resurfaced alongside the bloomer-like rational dress popularised in the bicycling culture of the 1890s, dress reform was largely deemed far less controversial by the turn of the twentieth century.  相似文献   

An Activist Approach to Sport Meets Youth From Socially Vulnerable Backgrounds: Possible Learning Aspirations     

Carla Luguetti  Kimberly L. Oliver  Luiz Eduardo Pinto Basto Tourinho Dantas  David Kirk 《Research quarterly for exercise and sport》2017,88(1):60-71

Purpose: This study was a 2-phase activist research project aimed at co-creating a prototype pedagogical model for working with youth from socially vulnerable backgrounds in a sport context. This article addresses the learning aspirations (learning outcomes) that emerged when we created spaces for youth to develop strategies to manage the risks they face in their community. Method: This study took place in a socially and economically disadvantaged neighborhood in a Brazilian city where we worked with a group of 17 boys aged 13 to 15 years old, 4 coaches, a pedagogic coordinator, and a social worker. During a 6-month period, we collected multiple sources of data including field journal entries/observations (38) and audio records of youth work sessions (18), coaches' work sessions (16), combined coaches and youth work sessions (3), and meetings between the lead and the 2nd author for debriefing and planning sessions (36). Results: By using an activist approach, 4 learning aspirations emerged: becoming responsible/committed, learning from mistakes, valuing each other's knowledge, and communicating with others. Conclusion: Findings suggest there is a need for more sports programs that start from young people's concrete needs and life situations and look to create places for youth to see alternative possibilities and take action.  相似文献   

Risk assessment: A comparative study of archive storage rooms     

Ana Catarina Pinheiro  Maria Filomena Macedo 《Journal of Cultural Heritage》2009,10(3):428-434

The goal of preventive conservation is to provide the correct maintenance of our cultural heritage in order to enrich our future. The Canadian Museum of Nature developed a risk model for preventive conservation that has proven useful in application to a Portuguese archive. This work applies this model to compare the magnitudes of specific risks estimated for this same archive collection when located in either of two pairs of storage rooms. These rooms are in two different parts of this building: two are in an older part and two are in a recent addition. It was, therefore, necessary to assess the building itself, both structurally and environmentally, as well as analyse its common human practices. In terms of the overall risk magnitude, the best room was found to be in the recent building and the worst in the older building. However, risks related to water problems were found to be higher in the new building. In this work cost-free measures and easy to implement recommendations are given in order to improve the quality of the storage rooms. A final comment on the method itself is also given.  相似文献   

Introducing medical students to radiological anatomy: The importance of experiential learning during the Covid-19 pandemic lockdowns     

Gustavo Bittencourt Camilo  Sérgio Murta Maciel  Gabriela Cumani Toledo Camilo  Kayan Felipe de Oliveira Andrade  Beatriz de Oliveira  Rayane da Silva Silveira  Isabella Nunes Borges Ferreira  Caroline da Silva Fernandes  Mariana Vilela Ferreira 《Anatomical sciences education》2022,15(5):980-984

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