Influence of kick frequency on metabolic efficiency and performance at a severe intensity in international monofin-swimmers     

Vercruyssen F  Boitel G  Alberty M  Nesi X  Bourdon L  Brisswalter J 《Journal of sports sciences》2012,30(10):1055-1061

The aim of this study was to examine the effect of kick frequency on metabolic efficiency and performance in elite monofin-swimmers at the surface. Seven participants of international calibre were requested to perform three separate time limit exercises conducted at an intensity corresponding to 97.5% of the velocity at the maximal oxygen uptake. The first Time Limit exercise was systematically conducted at a freely chosen kick frequency (FCK(F)) and the other Time Limit exercises were performed in random order at FCK(F)-10% and FCK(F) + 10%. The slow component of oxygen uptake (VO2sc) was identified independently of the Time Limit exercise (ranging from 180 to 243 ml · min(-1), P < 0.05). No significant change in energy cost of aquatic locomotion (ranging from 565 to (596 J · m(-1)) and [VO2sc) responses was observed between the three Time Limit exercises. An increase or decrease of 10% of the FCK(F) was associated with a significant reduction in Time Limit of -47.3% and -49.1%, respectively (P < 0.05). The analysis of the Time Limit exercise indicates that the selection of kick frequency other than FCK(F) is detrimental to overall monofin-swimming performance. Furthermore, the study results showed that the indicators of metabolic efficiency such as energy cost or [VO2sc) do not determine the performance response in elite monofin-swimmers at a severe intensity.  相似文献   

Mapping the impact of climate change on biomass accumulation on stone     

Antonio Gómez-Bolea  Esteve Llop  Xavier Ariño  Cesareo Saiz-Jimenez  Alessandra Bonazza  Palmira Messina  Cristina Sabbioni 《Journal of Cultural Heritage》2012,13(3):254-258

Several climate parameters affect the growth of organisms and, hence, their capacity to accumulate biomass. In the present research, we analyse the influence of two parameters, temperature and precipitation, on biomass accumulation on stone substrate, and propose a function to estimate it in temperate areas. The expression is subsequently used for the first time to evaluate the impact that climate change would have in biomass accumulation in Europe. The models on climate change predict an increase in temperature and precipitation in northern areas of Europe for the far future (2070–2099), which would lead to a higher accumulation of biomass. Otherwise, a significant reduction in precipitation is expected in southern areas of Europe, associated with a lower biomass accumulation in such areas.  相似文献   

Teaching and Learning Physics Using the Internet: the Baldufa Project     

Xavier Bohigas  Xavier Jaén  Montse Novell 《Higher Education in Europe》1998,23(2):233-240

The aim of the Baldufa project that is presented in this article is to help both teachers and students in teaching‐learning activities in physics. A certain amount of HTML documentation is available, at this moment, to be used by students as learning aids. Teachers can propose their own pedagogical strategies via the Internet. For these reasons, the authors have programmed a server and have conceived a teaching package in HTML language.  相似文献   

Variations of stroking parameters associated with 200 m competitive performance improvement in top-standard front crawl swimmers     

Huot-Marchand F  Nesi X  Sidney M  Alberty M  Pelayo P 《Sports biomechanics / International Society of Biomechanics in Sports》2005,4(1):89-99

The aim of this study was to analyse the variations of stroking parameters (speed, stroke length, stroke rate, and stroke index) associated with the 200 m front crawl competitive performance improvement. Two races completed by 17 top swimmers were analysed in the 200 m freestyle final of French or European championships, each final being separated by two years. All the swimmers' performances were bettered in the second race (mean +/- SD: 113.44 +/- 2.50 vs 111.78 +/- 2.71 s; p < 0.01) and were associated with a significant increase of stroke rate without variation of average stroke length and stroke index values (p > 0.05). Swimmers emphasized the first part of the race, with higher speed in the first three lengths, higher stroke rate in the first two lengths and lower stroke length in the first one. Stroke length and stroke rate variations were highly correlated (r = 0.98; p < 0.05). In 11 of the 17 swimmers, the improvement was concomitant with a decrease in stroke length and an increase in stroke rate. Only one swimmer's improvement was associated with a substantial increase in stroke length. These results highlighted that stroke length and stroke index cannot be considered as the only parameters linked to improvement in a 200 m crawl in adult swimmers competing at high standard. Moreover, an increase in stroke rate associated with a slight decrease in stroke length should not be considered as ineffective, especially at top standard.  相似文献   

New developments in intellectual property rights: Implications for geographic information systems     

Xavier R. Lopez 《The Journal of Academic Librarianship》1997,23(6):517-520

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DOES THE SCHOOL COMPOSITION EFFECT MATTER? EVIDENCE FROM BELGIAN DATA   总被引：2，自引：1，他引：1  

Xavier  Dumay  Vincent  Dupriez 《British Journal of Educational Studies》2008,56(4):440-477

ABSTRACT:  Even if the literature on the effects of pupil composition has been extensive, no clear consensus has been reached concerning the significance and magnitude of this effect. The first objective of this article is to estimate the magnitude of the school composition effect in primary schools (6th grade) in French-speaking Belgium. Different indicators of school composition are used: academic, socio-cultural, 'language' and sex composition. Except for sex composition, the results show that the school composition effect explains significant amount of between schools variance even after controlling for pupils' initial performance, socio-cultural background, and non-cognitive dispositions. The second objective is to examine covariance between school composition and several organisational variables and their joint effect on school performance. The second set of analyses is intended to question the conceptual nature of the school composition effect, establishing whether it is direct or indirect.  相似文献   

Inclusive education and social inequality: an update of the question and some geographical considerations     

Xavier Rambla  Ferran Ferrer  Aina Tarabini  Antoni Verger 《Prospects》2008,38(1):65-76

The aim of this article is to review the current state of inclusive education in the world and to suggest a few relevant considerations. The first section “Two parallel concerns” retraces the inescapable connections between the educational aspects of inclusive education and more general concerns regarding inequality. The second section “Inclusive education in academic publications” scrutinizes academic publications and identifies two major themes among their contents: at first sight the internal transformations occurring in schools attract attention, but subsequently the territorial environment also gives rise to some concern. The third section “Inclusive education in the publications of international organizations” notes our search criteria for sifting through the documentation of the World Bank, OECD and UNESCO. The IBE/UNESCO workshops reflect varied, though converging interpretations of the concept of inclusive education in different parts of the world. All the official publications, however, tend to concentrate on the internal dynamics of schools, and there are not many that take a look at relations between inclusive education and public policy. Our last section “The geographical dimension of inclusive education” puts forward a few arguments in favour of paying more attention to inclusive education at the local and national levels. The main reasons for highlighting the local dimension arise from the combined factors of social deprivation, the need to co-ordinate measures taken in schools and the possibility of allowing a significant opening for community participation. The main reasons for paying attention to the national dimension relate to possible synergies between inclusive education and the expansion of education (for example, is schooling progressing at the same pace at different educational levels?), as well as between inclusive education and social protection (for example, do the many educational conditions applied to cash transfers have consistent pedagogic implications?).  相似文献   

Epistemic Frames as an Analytical Framework for Understanding the Representation of Scientific Activity in a Modeling-Based Learning Unit     

Campbell  Todd  Fazio  Xavier 《Research in Science Education》2020,50(6):2283-2304

Research in Science Education - Set in the context of modeling-based learning (MBL), this research investigated the potential of epistemic frames as a theoretical and analytical framework for...  相似文献   

Identification of biomedical journals in Spain and Latin America     

Xavier Bonfill  Dimelza Osorio  Margarita Posso  Ivan Sol  Gabriel Rada  Ania Torres  Marcelo García Dieguez  Maricela Pia‐Pozas  Luisa Díaz‐García  Mario Tristn  Omar Gandarilla  David A. Rincn‐Valenzuela  Arturo Martí  Ricardo Hidalgo  Daniel Simancas‐Racines  Luis Lpez  Ricardo Correa  Antonieta Rojas‐De‐Arias  Csar Loza   scar Gianneo  Hector Pardo   《Health information and libraries journal》2015,32(4):276-286

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Popular education in solidarity economy     

José Francisco de Melo Neto  Francisco Xavier Pereira da Costa 《International Journal of Lifelong Education》2015,34(1):47-58

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