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1.
John Jerrim Luis Alejandro Lopez-Agudo Oscar D. Marcenaro-Gutierrez 《European Journal of Education》2020,55(2):248-260
The association between time devoted to homework and children's academic achievement has long been an issue of great debate. A small number of mainly correlational studies have been conducted into this issue in a primary school setting, but have produced somewhat mixed results. In this paper we contribute to this literature by investigating the relationship between time spent upon homework and children's outcomes across 24 countries. By using a student fixed-effects approach, capturing differences in homework time amongst the same student across different school subjects, we argue that our results are likely to be subject to less confounding than much of the existing literature. We find little evidence that the amount of homework time primary school children are assigned is related to their academic achievement. This holds true across a large number of countries, survives various robustness tests and does not vary by gender or socio-economic status. We interpret this finding as suggesting that the homework assigned to primary school pupils may not be adequate to produce a positive association, and needs be improved if this time-consuming activity is ever going to bring benefits for children's academic achievement. 相似文献
2.
Preservice Science Teachers' Beliefs About Teaching and Learning: The Influence of K-12 Field Experiences 总被引：1，自引：0，他引：1
Teaching is a complex task shaped by many external and internal influences, including the beliefs held by individual teachers. This study sought an understanding of the impact of field experiences on the beliefs developed by preservice science teachers. The participants were students in an undergraduate science education methods course that involved observation and teaching experiences in K-12 classrooms. The data used in this qualitative study included drawings representing beliefs and in-depth interviews with selected participants. The findings indicate that beliefs focused on two key dualities: learning through experience and transmission and student-centered and teacher-centered instruction. The findings also suggest that field experiences both reinforce and challenge the beliefs held by preservice science teachers. 相似文献
3.
There is growing evidence that school engagement, or more specifically disengagement, is a key indicator for predicting Early School Leaving. The aim of this article is to explore the impact of secondary schools in student (dis)engagement and subsequent opportunities to succeed in school. Drawing on data from a qualitative study in five secondary schools in Barcelona, the article discusses the role of school context in inhibiting or facilitating school engagement by exploring compositional effects, organisational and pedagogical practices, and teachers’ expectations. To do so a twofold perspective is adopted: firstly, we look at the main school features and their impact on students’ educational opportunities; and secondly, a systematic analysis of the dimensions of school engagement (behavioural, emotional and cognitive) is carried out. As a result, the article contributes to the identification of the most significant variables at school level that influence student engagement and their opportunities for school success. 相似文献
4.
Alejandro Torrejón Carlos Balsalobre-Fernández G. Gregory Haff 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):245-255
This study aimed to determine the suitability of the load-velocity relationship to prescribe the relative load (%1RM) in women, as well as to compare the load-velocity profile between sexes and participants with different strength levels. The load-velocity relationship of 14 men (1RM: 1.17 ± 0.19) and 14 women (1RM: 0.66 ± 0.13) were evaluated in the bench press exercise. The main findings revealed that: (I) the load-velocity relationship was always strong and linear (R2 range: 0.987–0.993), (II) a steeper load-velocity profile was observed in men compared to women (Effect size [ES]: 1.09), with men showing higher velocities for light loads (ES: ? 0.81 and ? 0.40 for the y-intercept and 30%1RM, respectively), but women reporting higher velocities for the heavy loads (ES: 1.14 and 1.50 at 90%1RM and 100%1RM, respectively); and (III) while the slope of the load-velocity profile was moderately steeper for weak men compared to their strong counterpart (ES: 1.02), small differences were observed between strong and weak women (ES: ? 0.39). While these results support the use of the individual load-velocity relationship to prescribe the %1RM in the bench press exercise for women, they also highlight the large disparities in their load-velocity profile compared to men. 相似文献
5.
Amador García-Ramos Belén Feriche Alejandro Pérez-Castilla Paulino Padial Slobodan Jaric 《European Journal of Sport Science》2017,17(6):690-698
This study aimed to explore the strength of the force–velocity (F–V) relationship of lower limb muscles and the reliability of its parameters (maximum force [F0], slope [a], maximum velocity [V0], and maximum power [P0]). Twenty-three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75?kg loads. The maximum and averaged values of F and V were obtained for the F–V relationship modelling. All F–V relationships were strong and linear independently whether observed from the averaged across the participants (r?≥?0.98) or individual data (r?=?0.94–0.98), while their parameters were generally highly reliable (F0 [CV: 4.85%, ICC: 0.87], V0 [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P0 [CV: 3.5%, ICC: 0.93]). Both the strength of the F–V relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the F–V relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the F–V relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested. 相似文献
6.
Alejandro Gomez-Bruton Jesús Montero-Marín Alejandro González-Agüero Alba Gómez-Cabello Javier García-Campayo Luis A. Moreno 《Journal of sports sciences》2018,36(4):365-377
This meta-analysis aims to determine the effects of regular swimming on bone mineral density (BMD) in young adults (18–30 years). A systematic search was performed in Pubmed, SPORTDiscus and the Cochrane Library from the earliest possible year to March 2016. Swimmers were compared to non-athletic controls (CG) and to high-impact athletes (HIGH). Effect sizes with the Hedges g in random effects models were developed. Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to CG in whole-body (g = ?0.20; P = 0.251), femoral neck (g = ?0.05; P = 0.818) and lumbar spine (g = 0.18; P = 0.492); and lower BMD in the whole-body (g = ?1.21; P < 0.001), femoral neck (g = ?1.51; P < 0.001) and lumbar spine (g = ?0.84; P = 0.017) than the HIGH. For the whole-body differences, the higher the latitude the smaller the differences between swimmers and HIGH (B = 0.10; P = 0.001). For the femoral neck differences, age also seemed to reduce the differences between groups (B = 0.19; P = 0.020). Young adult swimmers present similar BMD values than CG and lower values than HIGH. 相似文献
7.
Alejandro Pérez-Castilla Paulino Padial Antonio J. Morales-Artacho Belén Feriche 《Journal of sports sciences》2018,36(12):1331-1339
This study compared the effects of two velocity loss thresholds during a power-oriented resistance training program on the mechanical capacities of lower-body muscles. Twenty men were counterbalanced in two groups (VL10 and VL20) based on their maximum power capacity. Both groups used the same exercises, relative intensity and repetition volume, only differing in the velocity loss threshold of each set (VL10: 10% vs. VL20: 20%). Pre- and post-training assessments included an incremental loading test and a 15-m linear sprint to assess the force- and load-velocity relationships and athletic performance variables, respectively. No significant between-group differences (P > 0.05) were observed for the force-velocity relationship parameters (ES range = 0.15–0.42), the MPV attained against different external loads (ES range = 0.02–0.18) or the 15-m sprint time (ES = 0.09). A high between-participants variability was reported for the number of repetitions completed in each training set (CV = 30.3% for VL10 and 29.4% for VL20). These results suggest that both velocity loss thresholds induce similar changes on the lower-body function. The high and variable number of repetitions completed may compromise the velocity-based approach for prescribing and monitoring the repetition volume during a power-oriented resistance training program conducted with the countermovement jump exercise. 相似文献
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9.
Itziar Etxebarria María-José Ortiz Pedro Apodaca Aitziber Pascual Susana Conejero 《Infancia y Aprendizaje》2015,38(4):746-774
Moral pride, namely the pride generated by morally positive behaviour, can foster prosocial behaviour. To demonstrate this, two quasi-experimental studies were conducted with nine- to 11-year-old children. Study 1 analysed the effect of the pride felt after engaging in prosocial behaviour, in four classrooms from two different schools (N = 94). Study 2 analysed the effect of the pride generated by the evocation of a past example of one’s own prosocial behaviour, in four classrooms from another school (N = 77). The hypothesis was supported in Study 1 but not in Study 2. Interesting correlations were found between dispositional moral pride (measured using a scale designed ad hoc) and other relevant variables in the moral field: intention to engage in prosocial behaviour, habitual prosocial behaviour and dispositional empathy. In general, these studies attest to the importance of moral pride, both dispositional and that felt in a specific situation, in moral life. 相似文献
10.
Pascual Marqués-Bruna 《Sports Engineering》2011,13(4):195-204
This study examined aerodynamic properties and boundary layer stability in five cambered airfoils operating at the low Reynolds
numbers encountered in motor racing. Numerical modelling was carried out in the flow regime characterised by Reynolds numbers
0.82–1.29 × 106. The design Reynolds number of 3 × 106 was used as a reference. Aerodynamics variables were computed using AeroFoil 2.2 software, which uses the vortex panel method
and integral boundary layer equations. Validation of AeroFoil 2.2 software showed very good agreement between calculated aerodynamic
coefficients and wind tunnel experimental data. Drag polars, lift/drag ratio, pitching moment coefficient, chordwise distributions
(surface velocity ratio, pressure coefficient and boundary layer thickness), stagnation point, and boundary layer transition
and separation were obtained at angles of attack from −4° to 12°. The NASA NLF(1)-0414F airfoil offers versatility for motor
racing with a wide low-drag bucket, low minimum profile drag, high lift/drag ratio, laminar flow up to 0.7 chord, rapid concave
pressure recovery, high resultant pressure coefficient and stall resistance at low Reynolds numbers. The findings have implications
for the design of race car wings. 相似文献