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281.
Juan Miguel Campanario 《International Journal of Science Education》2013,35(10):1095-1110
This paper compares resistance by scientists to new ideas in scientific discovery with students' resistance to conceptual change in science learning. First, the resistance by students to abandon their misconceptions concerning scientific topics is studied. Next, the resistance by scientists to scientific discovery is studied and some of the causes of such resistance are explored. Some conclusions and direct implications for science teaching are suggested. 相似文献
282.
Machar Reid Miguel Crespo Francisco Atienza James Dimmock 《Journal of sports sciences》2013,31(11):1221-1228
Abstract The relationship between domestic professional tournament structure in women's tennis and the subsequent professional ranking success of a nation's female players is examined. The 2003 women's professional tennis tournament calendar provided the distribution of events in 33 countries. Criteria used to classify nations' success in women's professional tennis were as follows: number of players with Women's Tennis Association (WTA) points, number of players with Top 200 rankings, and the combined WTA ranking of a nation's Top 5 female players. Pearson product – moment correlations were performed between the number of tournaments and the three criteria. Considerable variation was observed in the number of events organized between nations (USA, n = 56; Thailand, n = 3). All countries had internationally ranked female players, and 24 nations had players ranked in the Top 200. Results revealed relationships between a nation's number of women's professional events and both that nation's number of professionally ranked players (r = 0.60; P < 0.01) and Top 200 players (r = 0.60; P < 0.01), as well as the combined ranking of their Top 5 players (r = ?0.52; P < 0.01). While a similar association was found between the number of professional events and players ranked in the men's game, there was no significant correlation between events held and the combined standing of nations' best five ranked players. Governing bodies and national associations in tennis should consider the provision of professional, domestic competition as key to the development of female tennis players. 相似文献
283.
Luciana Setaro Paulo Roberto Santos-Silva Eduardo Yoshio Nakano Cristiane Hermes Sales Newton Nunes Júlia Maria Greve 《Journal of sports sciences》2013,31(5):438-445
AbstractThe aim of this study was to test the hypothesis that magnesium supplementation influences the physical performance of volleyball players, as the efficacy of this approach remains questionable. Twenty-five professional male volleyball players were assigned randomly to experimental (350 mg Mg · d–1, 4 weeks) and control groups (500 mg maltodextrin · d–1, 4 weeks) maintaining inter-group homogeneity of urinary magnesium. Erythrocyte, plasma and urinary magnesium levels, plasma creatine kinase activity, lactate production, maximal oxygen uptake (VO2 max) and plyometric (squat jump, countermovement jump, countermovement jump with arm swing) and isokinetic (peak torque, potency and total work) performances were evaluated before (T0) and after (T1) supplementation. Levels of erythrocyte and urinary magnesium and creatine kinase activity and VO2 max remained within normal ranges in both groups. Plasma magnesium decreased significantly only within the experimental group. Significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump and countermovement jump with arm swing values were detected in the experimental group following magnesium supplementation, but not in the control group at T1. It is concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient. 相似文献
284.
Jesús Morenas Martín Vicente Luis Del Campo Marta Leyton Román Juan Miguel Gómez-Valadés Horrillo Juan Santiago Gómez Navarrete 《Journal of sports sciences》2013,31(15):1713-1721
AbstractCurrently, direct empirical evidence exists about the amount of mechanical load that climbers apply to each finger during several hand grips specific to sport climbing, but not yet in a specific hanging position.The objectives of this study are a) to draw and build a solid and rigid support that simulates the real action of a hand grip in a hanging position in sport climbing, to enable the measurement of the mechanical load endured by the fingers in a hanging position and in addition, b) to describe the distribution of mechanical load among fingers as a function of the level of climbing during different hand grips in a hanging position.Thirty young male participants took part in the initial phase of reliability of the measurements, while another 64 male climbers participated in the subsequent study phase to check the relations between independent and dependent variables. The level of on sight climbing and the total practice experience were used to define the groups. The research task consisted of performing hanging positions on the created support in order to measure the mechanical load endured by the fingers in the three most characteristic hand grips in climbing (crimp, half crimp and slope). It has been concluded that the performance level of the climbers had no influence on the production of a pattern of differentiated finger mechanical load during the research task. 相似文献
285.
Tomás García-Calvo Francisco Miguel Leo Inmaculada Gonzalez-Ponce Pedro Antonio Sánchez-Miguel Athanasios Mouratidis Nikos Ntoumanis 《Journal of sports sciences》2013,31(18):1738-1750
AbstractIn this longitudinal study, we examined the extent to which perceived coach- and peer-created motivational climates are associated with athlete-group cohesion and satisfaction with participation among Spanish soccer players competing in the Third National Division. Multilevel modelling analyses showed that perceived coach-created task climate was positively related to perceived cohesion and players’ satisfaction with their participation within their team. Also, perceived peer-created task climate related positively to perceived cohesion. The results indicate the importance of considering peer-related aspects of the motivational climate in addition to considering the coach-related aspects of the motivational climate when examining motivational group dynamics in sport. 相似文献
286.
Ricardo Mora-Custodio David Rodríguez-Rosell Juan Manuel Yáñez-García Miguel Sánchez-Moreno Fernando Pareja-Blanco Juan José González-Badillo 《Journal of sports sciences》2013,31(24):2856-2864
ABSTRACTThis study aimed to analyze the acute effect of inter-repetition rest (IRR) intervals on mechanical and metabolic response during four resistance exercise protocols (REPs). Thirty resistance-trained men were randomly assigned to: continuous repetitions (CR), 10 s (IRR10) or 20 s (IRR20) inter-repetition rest. The REPs consisted of 3 sets of 6, 5, 4 and 3 repetitions against 60, 70, 75 and 80% 1RM, respectively, in the full squat exercise. Muscle fatigue was assessed using: percentage of velocity loss over three sets, percentage of velocity loss against the ~1 m·s?1 load (V1 m·s?1), and loss of countermovement jump (CMJ) height pre-post exercise. Blood lactate was measured before and after exercise. The percentage of velocity loss over three sets and lactate concentration were significantly lower (P < 0.05) for IRR groups compared to CR in all REPs. The CR group showed a significantly higher (P < 0.05) velocity loss against V1 m·s?1 load and loss of CMJ height pre-post exercise than IRR groups in REP against 60% 1RM. In conclusion, both IRR groups produced a significant lower degree of fatigue compared to CR group. However, no significant differences were found in any measured variables between IRR configurations. 相似文献
287.
Campos-Sánchez A Martín-Piedra MÁ Carriel V González-Andrades M Garzón I Sánchez-Quevedo MC Alaminos M 《Anatomical sciences education》2012,5(5):273-280
Two questionnaires were used to investigate students' perceptions of their motivation to opt for reception learning (RL) or self‐discovery learning (SDL) in histology and their choices of complementary learning strategies (CLS). The results demonstrated that the motivation to attend RL sessions was higher than the motivation to attend SDL to gain new knowledge (P < 0.01) and to apply this acquired knowledge to diagnosis (P < 0.01), therapy (P < 0.01), and research (P < 0.05). Students also showed a stronger preference for RL based on motivations related to leadership (P < 0.01) and competition (P < 0.01), although the rates were very low in both cases (≤ 1.9 ± 1.1). Statistically significant differences were found between male and female students for leadership (higher in males), responsibility (higher in females), and acquiring new knowledge (higher in females only in RL). This study's findings for students' preferred CLS strategies suggested a greater need for additional complementary resources after RL than after SDL (P < 0.01). In conclusion, RL was associated with a greater need for complementary training resources such as textbooks, atlases, the internet, audiovisual media, and tutorials, whereas SDL was associated with a greater need to orient teaching and training toward medical practice. These results suggest the need to reorient both types of learning processes to enhance their effectiveness in teaching histology, especially in the case of SDL, which should place more emphasis on clinically oriented knowledge. Anat Sci Educ. © 2012 American Association of Anatomists. 相似文献
288.
This paper empirically examines to what extent being foreign and part of a multinational affects the endogenous relation between R&D and productivity. Our findings indicate that multinationals obtain in general higher R&D returns. Also, there is a negative foreignness effect in that domestic-owned multinationals outperform foreign subsidiaries. However, these effects are somehow moderated by the institutional distance between the home and host countries. These results, obtained for a panel of UK firms, are largely consistent with a set of hypotheses derived from the institutional and international business theories. 相似文献
289.
Vishal Gupta Insiya Jafferji Miguel Garza Vladislava O. Melnikova David K. Hasegawa Ronald Pethig Darren W. Davis 《Biomicrofluidics》2012,6(2)
Isolation and enumeration of circulating tumor cells (CTCs) are used to monitor metastatic disease progression and guide cancer therapy. However, currently available technologies are limited to cells expressing specific cell surface markers, such as epithelial cell adhesion molecule (EpCAM) or have limited specificity because they are based on cell size alone. We developed a device, ApoStream™ that overcomes these limitations by exploiting differences in the biophysical characteristics between cancer cells and normal, healthy blood cells to capture CTCs using dielectrophoretic technology in a microfluidic flow chamber. Further, the system overcomes throughput limitations by operating in continuous mode for efficient isolation and enrichment of CTCs from blood. The performance of the device was optimized using a design of experiment approach for key operating parameters such as frequency, voltage and flow rates, and buffer formulations. Cell spiking studies were conducted using SKOV3 or MDA-MB-231 cell lines that have a high and low expression level of EpCAM, respectively, to demonstrate linearity and precision of recovery independent of EpCAM receptor levels. The average recovery of SKOV3 and MDA-MB-231 cancer cells spiked into approximately 12 × 106 peripheral blood mononuclear cells obtained from 7.5 ml normal human donor blood was 75.4% ± 3.1% (n = 12) and 71.2% ± 1.6% (n = 6), respectively. The intra-day and inter-day precision coefficients of variation of the device were both less than 3%. Linear regression analysis yielded a correlation coefficient (R2) of more than 0.99 for a spiking range of 4–2600 cells. The viability of MDA-MB-231 cancer cells captured with ApoStream was greater than 97.1% and there was no difference in cell growth up to 7 days in culture compared to controls. The ApoStream device demonstrated high precision and linearity of recovery of viable cancer cells independent of their EpCAM expression level. Isolation and enrichment of viable cancer cells from ApoStream enables molecular characterization of CTCs from a wide range of cancer types. 相似文献
290.
José Ignacio Rojas-Sola Miguel Castro-García María del Pilar Carranza-Cañadas 《Journal of Cultural Heritage》2012,13(3):285-292
This article presents new research, which has the objective of quantifying the knowledge produced by historical technological innovations in the field of olive oil industrial heritage. It studies inventions related to the mechanical processes of the extraction of olive oil between 1826 and 1966, which are recorded in the Historical Archive of the Spanish Patent and Trademark Office. It uses a new adaptation of the methodology of knowledge management (KM) defined by Nonaka and Takeuchi. We have obtained the knowledge value of each innovation according to the level of technological knowledge registered at the time, while distinguishing between the historical evolution of inventions relating to milling and those relating to pressing. In the first analysis, the results show a recession in the quantitative level of knowledge in the olive oil sector with respect to the technological potential of the time. However, when contrasted with the events relating to industrial heritage at the time, it is possible to account for this technological evolution and prove the validity of the methodology used. The results show that general evolution of the knowledge generated has decreased, particularly in the pressing process, although this is not the case in the milling process. 相似文献