我们时代的教育

教育是当今世界的一个主要问题。尽管许多问题最先是从西方国家表现出来的,不过现在几乎已是人类普遍的问题:为什么孩子去倾听如此困难,--特别是男孩们?为什么许多孩子被赶出学校?为什么青少年自杀和吸毒率如此之高?是什么导致了学校暴力?我们能对上述问题一言蔽之:教育是否与我们时代的真正需求相匹配?比起以前,我们更需要发现一种新的与自     

Communities as Necessity in Information Literacy Development: Challenging the Standards

Contemporary standards suggest that information literate activity is a solitary process. As a corrective, research and pedagogical theories related to “learning communities” and “communities of practice” have become valuable sites of inquiry for librarians. The author provides strategies for making community a topic of instruction.     

School-based prevention: effects on obesity and physical performance after 4 years

Juvenile obesity is increasing worldwide. Preventive strategies are warranted. The school-based Children's Health Interventional Trial (the CHILT Project) combines health education and physical activity for children. The effect on obesity and physical performance was studied after four years in 12 primary schools compared with five control schools. Anthropometric data were recorded. Physical performance was measured by a coordination test for children (balancing backwards, one-legged obstacle jumping, lateral jumping, sideways movements) and a 6-min run (endurance). No difference in the prevalence and incidence of overweight and obesity was found between the intervention and control schools before and after the intervention. Remission of overweight was higher in the intervention schools (23.2 vs. 19.2%), but not significant. An increase in coordination related to lateral jumping and balancing backwards was apparent in the intervention schools (30.6, s = 10.8 vs. 26.1, s = 10.8, P = 0.005; 21.8, s = 11.8 vs. 19.4, s = 11.7, P = 0.007), and the increase in endurance performance tended to be higher in intervention schools (100.8, s = 122.7 vs. 92.8, s = 126.0, P = 0.055), adjusted for age, sex, baseline test result, and body mass index at final examination. Therefore, preventive intervention in primary school offers the possibility to improve physical performance in children. The prevalence and incidence of obesity were not affected.     

Vertical stiffness and muscle strain in professional Australian football

Abstract

The purpose of this study was to establish if vertical stiffness was greater in professional Australian rules footballers who sustained a lower limb skeletal muscle strain compared to those who did not, and to establish if a relationship between age, or training history, and vertical stiffness existed. Thirty-one participants underwent weekly rebound jump testing on a force platform over two seasons. Vertical stiffness was calculated for injured players and the uninjured cohort 1 and 3 weeks prior to sustaining an injury and at the end of preseason. Eighteen athletes were in the “uninjured” cohort and 13 in the “injured” cohort. No significant difference in vertical stiffness was observed between groups (P = 0.18 for absolute stiffness; P = 0.08 for stiffness relative to body mass), within groups (P = 0.83 and P = 0.88, respectively) or for a time*cohort interaction (P = 0.77 and P = 0.80, respectively). No relationship between age and vertical stiffness existed (r = ?0.06 for absolute and relative stiffness), or training history and vertical stiffness (r = ?0.01 and 0.00 for absolute and relative stiffness, respectively) existed. These results and others lend to suggest that vertical stiffness is not related to lower limb muscle strain injury.     

Assessment of the risk and biomechanical consequences of lateral epicondylalgia by estimating wrist and finger muscle capacities in tennis players

Previous studies suggested that a pronounced weakness of the extensor muscles relative to the flexor muscles could increase the risk of occurrence of lateral epicondylalgia. This study investigates this hypothesis by estimating the ratio of extensor to flexor muscle capacities among healthy non-players (n = 10), healthy tennis players (n = 20), symptomatic players (n = 6), and players who have recovered from lateral epicondylalgia (n = 6). Maximum net joint moments in flexion or extension were measured during seven tasks involving the voluntary contraction of wrist and fingers. Using these data, the muscle capacities of the main muscle groups of the hand (wrist flexors, wrist extensors, finger flexors, finger extensors, and intrinsic muscles) were estimated using a musculoskeletal model. These capacities were then used to compute the extensor/flexor capacity ratios about the wrist and the finger joints. Compared to healthy non-players, healthy players presented higher extensor muscle capacities and greater capacity ratios showing that playing tennis generates specific adaptations of muscle capacities. Interestingly, symptomatic players, similar to those of non-players, showed more imbalanced ratios than healthy players. These results confirm that the ratio of extensor/flexor muscle capacities seems to be associated with lateral epicondylalgia and can be further used to understand its incidence and consequences.     

Reducing prolonged sedentary time using a treadmill desk acutely improves cardiometabolic risk markers in male and female adults

This study evaluated the acute effects of interrupting prolonged sitting with an accumulated 2 h of light-intensity walking on postprandial cardiometabolic risk markers. In this randomised crossover trial, 24 participants (twelve males) aged 18–55 years took part in two, 6.5 h conditions: 1) prolonged sitting (SIT) and 2) sitting interrupted hourly with 20 min light-intensity treadmill desk walking at between 1.2–3.5 km/h^?1 (INT-SIT). Standardized meals were provided at 0 h and 3 h. Blood samples and blood pressure measures were taken hourly. Statistical analyses were completed using linear mixed models. Postprandial incremental area under the curve responses (mmol/L?6.5 h) for glucose (4.52 [3.47, 5.56] and 6.66 [5.62, 7.71] for INT-SIT and SIT, respectively) and triglycerides (1.96 [0.96, 2.96] and 2.71 [1.70, 3.71] for INT-SIT and SIT, respectively) were significantly lower in INT-SIT than SIT. Mean systolic and diastolic blood pressure responses were lower by 3% and 4%, respectively, in INT-SIT than SIT (P < 0.05). There was no significant condition x sex interaction effect for any outcomes (P > 0.05). These findings suggest that interrupting sitting with an accumulated 2 h of light-intensity walking acutely improves cardiometabolic risk levels in males and females compared with prolonged sitting.     

A Bayesian Framework for XML Information Retrieval: Searching and Learning with the INEX Collection

Most recent document standards like XML rely on structured representations. On the other hand, current information retrieval systems have been developed for flat document representations and cannot be easily extended to cope with more complex document types. The design of such systems is still an open problem. We present a new model for structured document retrieval which allows computing scores of document parts. This model is based on Bayesian networks whose conditional probabilities are learnt from a labelled collection of structured documents—which is composed of documents, queries and their associated assessments. Training these models is a complex machine learning task and is not standard. This is the focus of the paper: we propose here to train the structured Bayesian Network model using a cross-entropy training criterion. Results are presented on the INEX corpus of XML documents.