Sodium bicarbonate ingestion increases glycolytic contribution and improves performance during simulated taekwondo combat

Purpose: To investigate the effect of sodium bicarbonate (NaHCO₃) on performance and estimated energy system contribution during simulated taekwondo combat. Methods: Nine taekwondo athletes completed two experimental sessions separated by at least 48?h. Athletes consumed 300?mg/kg body mass of NaHCO₃ or placebo (CaCO₃) 90?min before the combat simulation (three rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration [La^?] and rating of perceived exertion (RPE) were measured before and after each round, whereas heart rate (HR) and the estimated contribution of the oxidative (W_OXI), ATP (adenosine triphosphate)-phosphocreatine (PCr) (W_PCR), and glycolytic (W_{[ La^? ]}) systems were calculated during the combat simulation. Results: [La^?] increased significantly after NaHCO₃ ingestion, when compared with the placebo condition (+14%, P?=?0.04, d?=?3.70). NaHCO₃ ingestion resulted in greater estimated glycolytic energy contribution in the first round when compared with the placebo condition (+31%, P?=?0.01, d?=?3.48). Total attack time was significantly greater after NaHCO₃ when compared with placebo (+13%, P?=?0.05, d?=?1.15). W_OXI, W_PCR, VO₂, HR and RPE were not different between conditions (P?>?0.05). Conclusion: NaHCO₃ ingestion was able to increase the contribution of glycolytic metabolism and, therefore, improve performance during simulated taekwondo combat.     

The transfer of strength and power into the stroke biomechanics of young swimmers over a 34-week period

The purpose of this study was to learn the interplay between dry-land strength and conditioning, and stroke biomechanics in young swimmers, during a 34-week training programme. Twenty-seven swimmers (overall: 13.33?±?0.85 years old; 11 boys: 13.5?±?0.75 years old; 16 girls: 13.2?±?0.92 years old) competing at regional- and national-level competitions were evaluated. The swimmers were submitted to a specific in-water and dry-land strength training over 34 weeks (and evaluated at three time points: pre-, mid-, and post-test; M1, M2, and M3, respectively). The 100-m freestyle performance was chosen as the main outcome (i.e. dependent variable). The arm span (AS; anthropometrics), throwing velocity (TV; strength), stroke length (SL), and stroke frequency (SF; kinematics) were selected as independent variables. There was a performance enhancement over time (M1 vs. M3: 68.72?±?5.57?s, 66.23?±?5.23?s; Δ?=??3.77%; 95% CI: ?3.98;?3.56) and an overall improvement of the remaining variables. At M1 and M2, all links between variables presented significant effects (p?p?≤?.05). Between M1 and M3, the direct effect of the TV to the stroke biomechanics parameters (SL and SF) increased. The model predicted 89%, 88%, and 92% of the performance at M1, M2, and M3, respectively, with a reasonable adjustment (i.e. goodness-of-fit M1: χ²/df?=?3.82; M2: χ²/df?=?3.08; M3: χ²/df?=?4.94). These findings show that strength and conditioning parameters have a direct effect on the stroke biomechanics, and the latter one on the swimming performance.     

Physical activity and school recess time: differences between the sexes and the relationship between children's playground physical activity and habitual physical activity

The aims of this study were: (1) to observe participation in moderate-to-vigorous physical activity (MVPA) during school recess periods; (2) to determine the relative importance of physical activity during recesses to overall daily physical activity; and (3) to examine differences in physical activity between the sexes during unstructured recess periods. The participants were 22 school children (10 boys, 12 girls) aged 8 - 10 years (mean = 8.9, s = 0.7) in the third and fourth grades. Daily totals for the physical activity variables were calculated by summing the values for each hour of 14 h of physical activity measurements (08:00 to 22:00 h). Recess times (minutes) were as follows: morning 10:30 to 11:00 h and afternoon 15:30 to 16:00 h. We did not differences between boys and girls in daily total accelerometer counts or the overall time spent in MVPA. However, girls were significantly (P < 0.05) more involved (38%) in MVPA during recess time than boys (31%). Participation in MVPA during recess contributes significantly more (P < 0.05) for girls (19%) than boys (15%) to the total amount of physical activity suggested by international health-related physical activity guidelines, while the percentage of time engaged in MVPA during recess time at school accounts for a small amount of the daily MVPA (6% for boys and 8% for girls). The results of this study suggest that school recess time is an important setting to promote MVPA and contributes to daily physical activity in young children, especially in girls.     

论云南清代彝族教育家文论家李云程

云南清代彝族李云程编著的《古文笔法百篇》,不遵成法,独辟蹊径,而取文章的笔法作 为选编的依据。从编辑学角度看,他以人为本,把教学法则运用到编纂此书中;从文章学角度看,其评论 广集众家之言,不少真知灼见,往往发他人所未发。该书成就他成为优秀的教育家、文论家。     

Contributions from sociology of science to mathematics education in Brazil: logic as a system of beliefs

In Brazil, mathematics education was associated with Jean Piaget’s theory. Scholars in the field of education appropriated Piaget’s work in different ways, but usually emphasized logical aspects of thought, which probably lead to an expansion of mathematics education influenced by psychology. This study attempts to extend the range of interlocutions and pose a dialogue between the field of mathematics education in Brazil and the sociology of science proposed by David Bloor. The main point of Bloor’s theory is that logical-mathematical knowledge is far from being true and universal and is socially conditioned. In particular we will be discussing the first principle of the strong program, which deals with conditions that generate beliefs promoted by education policies in Brazil, such as the MEC/USAID treaties. In this case the “naturalization of logic” was stimulated by a widespread diffusion of both Piaget studies and the Modern Mathematics Movement.     

Decision making for borderline cases in pass/fail clinical anatomy courses: The practical value of the standard error of measurement and likelihood ratio in a diagnostic test

Several studies have shown that the standard error of measurement (SEM) can be used as an additional “safety net” to reduce the frequency of false‐positive or false‐negative student grading classifications. Practical examinations in clinical anatomy are often used as diagnostic tests to admit students to course final examinations. The aim of this study was to explore the diagnostic value of SEM using the likelihood ratio (LR) in establishing decisions about students with practical examination scores at or below the pass/fail cutoff score in a clinical anatomy course. Two hundred sixty‐seven students took three clinical anatomy practical examinations in 2011. The students were asked to identify 40 anatomical structures in images and prosected specimens in the practical examination. Practical examination scores were then divided according to the following cutoff scores: 2, 1 SEM below, and 0, 1, 2 SEM above the pass score. The positive predictive value (+PV) and LR of passing the final examination were estimated for each category to explore the diagnostic value of practical examination scores. The +PV (LR) in the six categories defined by the SEM was 39.1% (0.08), 70.0% (0.30), 88.9% (1.04), 91.7% (1.43), 95.8% (3.00), and 97.8% (5.74), respectively. The LR of categories 2 SEM above/below the pass score generated a moderate/large shift in the pre‐ to post‐test probability of passing. The LR increased the usefulness and practical value of SEM by improving confidence in decisions about the progress of students with borderline scores 2 SEM above/below the pass score in practical examinations in clinical anatomy courses. Anat Sci Educ. © 2013 American Association of Anatomists.     

Preprint policies among 14 academic publishers

The objective of this study was to assess how 14 large and established scientific publishers have adopted the use of preprints and how their policies changed in a one-year period between June 2017 and June 2018, if any. The core search was performed using the Sherpa/RoMEO database. Of all publishers (2516, now 2553) listed in the RoMEO database, 80.3% of the publishers examined allow self-archiving, but only half of the publishers (47.3%) allow the archiving of preprints in February of 2018, while this percentage increased to 48% in June 2018. These data were practically constant over a one-year period even as the number of preprint servers has increased. Several exceptions exist among journals within each of the tested Sherpa/RoMEO-indexed publishers, and in some cases, a reversal in policy was observed, i.e., from allowing to no longer allowing the archival of preprints.     

The good,the bad and the ugly: Three faces of social media usage by local governments

This article explores the determinants of local governments' use of social networking sites. It does so by analysing the relative impact of institutional, political and social determinants, while controlling for the impact of mayors' traits and social characteristics of municipalities on local governments levels of activity on Facebook. Empirically, this article presents a within-case analysis of Portuguese municipalities' activity on social media, aiming to shed light on the strategic use of social media by local governments. A coherent picture associated with politically pro-active local governments emerges from the results: higher levels of social media activity appear in municipalities with more competitive local elections and higher commitment to transparency. Moreover, findings suggest that local governments tend to be concerned with the low levels of voter turnout, potentially resorting to social media as a powerful tool to increase civic engagement and (offline) political participation. Levels of Facebook activity are significantly higher in larger and wealthier municipalities. The results indicate that Facebook official pages of municipalities are part of a larger arsenal of tools to promote political engagement and activity levels signal a propensity to involve citizens pro-actively.     

Constructing and Using Multimodal Narratives to Research in Science Education: Contributions Based on Practical Classroom

This study deals with the problem of how to collect genuine and useful data about science classroom practices, and preserving the complex and holistic nature of teaching and learning. Additionally, we were looking for an instrument that would allow comparability and verifiability for teaching and research purposes. Given the multimodality of teaching and learning processes, we developed the multimodal narrative (MN), which describes what happens during a task and incorporates data such as examples of students’ work, photos, diagrams, etc. Also, it describes teachers’ intentions, preserving the nature of teaching practice in natural settings and it is verifiable and comparable. In this paper, we show how the MN was developed and present the protocol that was used for its construction. We identify the main characteristics of the MN and place it in the context of international research. We explore the potential of the MN for research purposes, illustrating its use in a research study that we carried out. We find that the MN provides a way to gather, organize and transform data, avoiding confusing and time-consuming manipulation of data, while minimizing the natural subjectivity of the narrator. The same MN can be used by the same or by different researchers for different purposes. Furthermore, the same MN can be used with different analysis techniques. It is also possible to study research practices on a large scale using MNs from different teachers and lessons. We propose that MNs can also be useful for teachers’ professional development.