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11.
This study examined arm and leg coordination and propulsion during the flat breaststroke in nine elite male and eight elite female swimmers over three race paces (200?m, 100?m and 50?m). Coordination was expressed using four temporal gaps (T1, T2, T3, T4), which described the continuity between the propulsive phases of the limbs, as recorded on a video device (50 Hz). Glide duration was denoted T1, the time between the beginning of arm and leg recovery was denoted T2, the time between the end of arm and the leg recovery was denoted T3, and the time between 90° of flexion during arm recovery and 90° during leg recovery was denoted T4. Using these temporal gaps, four stroke phases (propulsion, glide, recovery and leg insweep) could be followed over a complete arm and leg stroke. The total duration of arm and leg propulsion was assessed by a new index of flat breaststroke propulsion (IFBP). Velocity, stroke rate and stroke length were also calculated for each pace. The elite swimmers showed short T2, T3 and T4; moreover, T1 decreased when the pace increased. Expertise in the flat breaststroke was thus characterized by synchronized arm and leg recoveries and increased continuity in the arm and leg propulsions with increasing velocity. Differences between the sexes in the spatio-temporal parameters were possibly due to anthropometric differences (the men were heavier, older and taller than the women) and different motor organization linked to arm and leg coordination (shorter T3, body glide and body recovery, and greater body propulsion and higher IFBP in the men). The men's propulsive actions showed greater continuity, particularly in the sprint. The best men adopted a superposition coordination and thus had the ability to overcome very great active drag. Temporal gap measurement and the IFBP are practical indicators of arm and leg coordination and propulsion that can be exploited by coaches and swimmers to increase the continuity between propulsive actions during the flat breaststroke.  相似文献   
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Abstract

A classification system of treading water based on a conceptual typology was first established and then verified empirically. The typology was established on two concepts: the nature of the forces created within the water and the type of inter-limb coordination used. Thirty-eight participants were videotaped while treading water. Multivariate statistics were used to understand how the different behavioural types related to expertise. Three distinct groups of coordination patterns were adopted during treading water. A support vector machine procedure was used as a confirmatory procedure. The data mining process provides a methodological framework to analyse expertise in sports activities, and in this context suggests that a taxonomy can be established among the numerous coordination solutions that allow humans to create stabilising forces in the water.  相似文献   
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The purpose of this paper was to determine the effects of deep approaches to learning on the moral reasoning development of 1,457 first-year students across 19 institutions. Results showed a modest positive relationship between our measures of deep approaches to learning and moral reasoning at the end of the first year of college even after controlling for precollege moral reasoning. After accounting for a host of demographic and relevant student characteristics and for the natural clustering of students, we found that the integrative learning subscale, which captures students’ participation in activities designed to integrate information from varied sources and diverse perspectives, positively affected moral reasoning among first-year students. Implications for researchers and practitioners are discussed.  相似文献   
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ABSTRACT

Although information and communication technologies (ICTs), such as smartphones, tablets, and the internet, have all become increasingly important in modern society, available studies on the adoption of ICTs have mostly focused on healthy and community-dwelling “young-old” adults. Relatively little is known about ICT use among long-term care residents, such as “old-old” adults, who often have various functional impairments and live in institutionalized settings. The study includes data on ICT use (TV, radio, computers, smartphones, tablets, and internet) among a large sample of 940 residents (mean age: 87.6 years) living in 20 retirement homes in Zurich, Switzerland. Twenty-one percent of residents reported using the internet, 13% used a smartphone, and 5% used a tablet. Younger older adults, those with more education, those with lower nursing-care levels, and those who reported being particularly interested in technology were more likely to own more than one ICT device. Compared with nonusers, internet users were more likely to be younger, better educated, and more interested in technology in general. Modern ICT usage has reached the long-term care sector and appears to play a significant role in many residents’ lives. Researchers should continue to examine the role of ICTs in the lives of older adults in general and for residents in long-term care in particular, given that this population is often ignored in studies of older adults and ICT use.  相似文献   
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The present study aims at examining variables (at individual and class level) that influence the accuracy of teacher judgments of second and third graders’ reading abilities (decoding and reading comprehension). Data of 1,468 students and 86 teachers were collected. Due to the nested structure of the data, multilevel regression analyses were applied. Results revealed about 5% of the variance in judgment accuracy at class level. Generally, teachers judged reading comprehension abilities more accurately than decoding abilities. Low‐achieving students’ abilities, though, were judged less accurately. Accuracy in judging decoding was higher in small classes and in students with special educational needs. Accuracy in judging reading comprehension grew along the years (higher in Grade 3 and at the end of the academic year). Additionally, teachers judged second language learners' reading comprehension less accurately. The results are discussed in the light of implications for teacher training.  相似文献   
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Data mining is emerging as one of the key features of many homeland security initiatives. Often used as a means for detecting fraud, assessing risk, and product retailing, data mining involves the use of data analysis tools to discover previously unknown, valid patterns and relationships in large data sets. In the context of homeland security, data mining is often viewed as a potential means to identify terrorist activities, such as money transfers and communications, and to identify and track individual terrorists themselves, such as through travel and immigration records. However, compared to earlier uses of data mining by government, some of the homeland security data mining applications represent a significant expansion in the quantity and scope of data to be analyzed. Three of the higher profile initiatives include the now defunct Terrorism Information Awareness (TIA) project, the recently canceled Computer-Assisted Passenger Prescreening System II (CAPPS II), and the Multistate Anti-Terrorism Information Exchange (MATRIX) pilot project. This article examines the evolving nature of data mining for homeland security purposes, the limitations of data mining, and some of the issues raised by its expanding use, including data quality, interoperability, mission creep, and privacy.  相似文献   
19.
Journal of Cultural Economics - A correction to this paper has been published: https://doi.org/10.1007/s10824-021-09408-5  相似文献   
20.
Effect of expertise on butterfly stroke coordination   总被引:1,自引:0,他引:1  
The aim of this study was to compare the arm-to-leg coordination in the butterfly stroke of three groups of male swimmers of varying skill (10 elite, 10 non-elite, and 10 young swimmers) at four race paces (400-m, 200-m, 100-m, and 50-m paces). Using qualitative video analysis and a hip velocity-video system (50 Hz), key events of the arm and leg movement cycles were defined and four-point estimates of relative phase were used to estimate the arm-to-leg coordination between the propulsive (pull and push of arms and downward movement of leg undulation) and non-propulsive phases (entry, catch, and recovery of arms and upward movement of leg undulation). With increasing race pace, the velocity, stroke rate, and synchronization between the arm and leg key points also increased, indicating that velocity and stroke rate may operate as control parameters. Finally, these changes led to greater continuity between the propulsive actions, which is favourable for improving the swim velocity, suggesting that coaches and swimmers should monitor arm-to-leg coordination.  相似文献   
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