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Compared to competitive runners, recreational runners appear to be more prone to injuries, which have been associated with foot strike patterns. Surprisingly, only few studies had examined the foot strike patterns outside laboratories. Therefore, this study compared the foot strike patterns in recreational runners at outdoor tracks with previously reported data. We also investigated the relationship between foot strike pattern, speed, and footwear in this cohort. Among 434 recreational runners analysed, 89.6% of them landed with rearfoot strike (RFS). Only 6.9 and 3.5% landed with midfoot and forefoot, respectively. A significant shift towards non-RFS was observed in our cohort, when compared with previously reported data. When speed increased by 1 m/s, the odds of having forefoot strike and midfoot strike relative to RFS increased by 2.3 times and 2.6 times, respectively. Runners were 9.2 times more likely to run with a forefoot strike in minimalists compared to regular running shoes, although 70% of runners in minimalists continued to use a RFS. These findings suggest that foot strike pattern may differ across running conditions and runners should consider these factors in order to mitigate potential injury.  相似文献   
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In this systematic review of literature that spans 1975–2015, integrated reading and writing interventions for students with learning disabilities (LD) or students with academic difficulties were evaluated to understand the extant research, identify encouraging practices, and guide future research. Ten studies met inclusion criteria and each study was evaluated according to the relevant What Works Clearinghouse (WWC) design standards. Eight of the 10 investigations were conducted with students in grades 4–8. While only 4 of the 10 studies met WWC design with or without reservations, results from these studies are encouraging. Study findings suggest several areas for immediate future research relating to methodological and treatment variables and considerations for classroom instruction in order to respond to advanced expectations for the successful integration of reading and writing across subjects. In addition to employing stronger experimental designs and additional replications of encouraging studies, future research should explore the utility of integrated reading and writing interventions with secondary students with who have academic difficulties.  相似文献   
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This study investigated relationships between social media motivation, relative preferences for social media type, and network heterogeneity, using a U.S. national survey. By classifying social media into the symmetrical and the asymmetrical, we showed that relationship motivation was more likely to be associated with a preference for the symmetrical type, whereas information motivation with a preference for the asymmetrical. Network heterogeneity was positively predicted by relationship motivation but not by information motivation. Finally, a relative preference for the symmetrical type was found to mediate the association between relationship motivation and network heterogeneity.  相似文献   
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OBJECTIVE: This study compared recidivism rates for alleged maltreatment perpetrators whose initial report was substantiated and those whose initial report was not substantiated, to determine whether they returned to the child welfare system at differing rates. METHOD: Statewide administrative child welfare services data over a period of 4 1/2 years was analyzed. The sample included 31,531 perpetrators of intrafamilial maltreatment. Separate analyses were conducted for each type of maltreatment (sexual abuse, physical abuse, and neglect). RESULTS: Bivariate relationships (substantiation status and recidivism) were analyzed using survival curves, and the study found that recidivism patterns differed by type of maltreatment and by substantiation status at the index event. Multivariate analyses using Cox Proportional Hazards models found that bivariate relationships held true even when controlling for neighborhood mean income, ethnicity, and gender. CONCLUSIONS: The study's finding that perpetrators whose index event was not substantiated return to the child welfare system at a high rate suggests the need to learn how to discriminate those unsubstantiated alleged perpetrators who are most at risk for recidivism. The finding of frequent cross-type recidivism indicates that intervention should focus on common themes across maltreatment types.  相似文献   
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This study explored kindergartners' and first graders' collaborative processes to understand the nature of peer collaboration and the learning opportunities afforded by peer discourse. Data were drawn from 6 dyads who participated in a computer writing project for 2 school semesters. Children's videotaped interactions were analyzed with the focus on understanding how children's collaborative roles and patterns changed over time. Examination of video data and children's computer products revealed that (a) children's interaction patterns changed from a more independent style toward a more integrative style, as shown in their distribution of control over mouse and keyboard and in the written outcomes of their collaboration; (b) a shift in role patterns emerged across repeated instances of peer collaboration so that children began alternating the roles of leader and observer, and less competent children began carrying out more important tasks; and (c) the computer served as an object of reference for children to sustain their interaction and stay on task.  相似文献   
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This paper examines the factors affecting the performance of global query expansion based on term co-occurrence data and suggests a way to maximize the retrieval effectiveness. Major parameters to be optimized through experiments are term similarity measure and the weighting scheme of additional terms. The evaluation of four similarity measures tested in query expansion reveal that mutual information and Yule's Y, which emphasize low frequency terms, achieve better performance than cosine and Jaccard coefficients that have the reverse tendency. In the evaluation of three weighting schemes, similarity weight performs well only with short queries, whereas fixed weights of approximately 0.5 and similarity rank weights were effective with queries of any length. Furthermore, the optimal similarity rank weight achieving the best overall performance seems to be the least affected by test collections and the number of additional terms. For the efficiency of retrieval, the number of additional terms needs not exceed 70 in our test collections, but the optimal number may vary according to the characteristics of the similarity measure employed.  相似文献   
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This paper presents a size reduction method for the inverted file, the most suitable indexing structure for an information retrieval system (IRS). We notice that in an inverted file the document identifiers for a given word are usually clustered. While this clustering property can be used in reducing the size of the inverted file, good compression as well as fast decompression must both be available. In this paper, we present a method that can facilitate coding and decoding processes for interpolative coding using recursion elimination and loop unwinding. We call this method the unique-order interpolative coding. It can calculate the lower and upper bounds of every document identifier for a binary code without using a recursive process, hence the decompression time can be greatly reduced. Moreover, it also can exploit document identifier clustering to compress the inverted file efficiently. Compared with the other well-known compression methods, our method provides fast decoding speed and excellent compression. This method can also be used to support a self-indexing strategy. Therefore our research work in this paper provides a feasible way to build a fast and space-economical IRS.  相似文献   
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