The Scottish engineer Robert Stirling took out his first patent for an engine producing motive power by the expansion of air as long ago as 1816. In his lifetime one such engine, of 145 HP, was built to drive machinery at a Dundee foundry but engines of this type have never been widely adopted. This article argues that new technology and radical changes in the world energy pattern open up entirely new prospects for the Stirling engine. 相似文献
The aim of this case study was to determine whether a sailor's deliberate choice of a conservative strategy to manage sleep deprivation would allow him to cross the Pacific Ocean and to minimize his state of anxiety and perceived fatigue. The participant, who had more than 10 years' sailing experience in severe conditions, was tested on a small catamaran without any living quarters during a solo Pacific Ocean crossing. Estimations of sleep hours, state anxiety, and perceived fatigue were self-reported by the sailor on a daily basis using a specific questionnaire. The most important finding is that the sailor's deliberate sleep strategy, 5.4 h sleep per day (24% less than on-shore), was enough to keep his anxiety and perceived fatigue within acceptable limits and enabled him to achieve his goal, which was the first crossing of the Pacific Ocean on a catamaran of less than 6 m. In conclusion, our results suggest that the sailor observed in the present case study was able to minimize anxiety and perceived fatigue with adequate sleep to optimize his performance, security, and to achieve his goal. 相似文献
Innovation has become a very popular concept over the twentieth century. However, few have stopped to study the origins of the category and to critically examine the studies produced on innovation. This paper conducts such an analysis on one type of innovation, namely technological innovation. The study of technological innovation is over one hundred years old. From the early 1900s onward, anthropologists, sociologists, historians, and economists began theorizing about technological innovation, each from his own respective disciplinary framework. However, in the last forty years an economic and ??dominant?? understanding of technological innovation has developed: technological innovation defined as commercialized invention. This paper documents the origins of this representation and the tradition of research to which it gave rise: ??innovation studies.?? More specifically, it analyzes what distinguishes this tradition from that concerned with technological change as the use of inventions in industrial production, and looks at why such a tradition originated in Europe. 相似文献
The production of grammatical markers takes a long time to master. Even when students know the rules, they do not systematically apply them. However, few studies have demonstrated the efficacy of interventions to improve this competence, and no study has addressed the issue at the cognitive and motivational levels jointly. Our study demonstrates the effect of combining progressive treatment, based on cognitive cost and self-assessment, on grammatical spelling and on self-efficacy beliefs. Over 8 weekly 50-minute lessons, four groups of 18, 20, 18 and 21 ninth graders received, respectively, progressive treatment alone, coupled with self-assessment, coupled with feedback, or coupled with self-assessment and feedback. These intervention groups were compared with a control group of 36 students receiving standard spelling instruction. The interventions focussed on past participle inflections, which are particularly difficult to learn for French-speaking students. The results indicated that (a) students who received progressive treatment made more progress than the control group students in spelling past participle inflections, presenting a transfer and a first degree of automatisation of the rules. The results also indicated that (b) students who participated in progressive treatment with self-assessment improved even more on the spelling tests, including free text production, and in their self-efficacy beliefs, demonstrating a deeper automatisation of the grammatical rules combined with an increase in perceived efficacy. This research shows that learning benefits from instructional practices that provide both cognitive cost and motivational support. 相似文献
Although a vast body of studies regarding the variables related to students’ achievement exists, only a handful has investigated how these variables combine and interact together. Such an investigation might make it possible to more accurately illustrate the heterogeneity of students enrolling in university and assess the impact of this diversity on academic achievement. The current study focused on the person-centered approach and investigated the possibility of determining significant subgroups of freshmen in the very first week of the academic year in the Belgian educational context. Using k-mean clustering, 2178 freshmen were classified according to their past performance, socioeconomic status, study choice process, and academic self-efficacy beliefs at the beginning of the first year at university. Analyses of variance were also conducted to analyze the relationship between these student clusters and academic achievement outcomes. Six distinct profiles of students were identified representing different combinations of achievement predictors. Results revealed different odds of success among these profiles. The implications of our approach to the understanding of the heterogeneity of freshmen and the first-year achievement process are discussed. 相似文献
Introduction: Social roles in physical education (PE) classes have been much studied, especially mentoring and coaching roles. The studies have shown that mentoring and coaching are beneficial not only for motor learning, but also for methodological and social learning. To our knowledge, the role of the student referee in PE lessons has never been specifically studied. Yet refereeing is essential in many sports, including team sports, and provides an experience of responsibility that many teachers want to offer their students. Encouraging students to take on this role can nevertheless be difficult.
Objective: The objective of the present study was to gain access to students’ lived experiences as referees in order to determine their strategies for being effective. We particularly wanted to determine which concerns organized their activity so that we could identify a refereeing typology that would be useful for PE teaching. Our study is original in that we did not rely exclusively on experiential data to understand student refereeing activity. We also collected data on the students’ motivation in order to better understand their experiences. For this purpose, the study was conducted within the methodological framework of course-of-action theory and self-determination theory.
Method: Seventy-four students from three classes in the third year of middle school (about 13 years old) participated in the study. Among them, four (two girls and two boys and not experts in the sports in which they were going to referee) had volunteered to be filmed and to participate in self-confrontation interviews. The other students completed two questionnaires to provide information on their motivation for refereeing. The situations studied were basketball and handball matches held at the end of the lessons.
Two categories of data were collected: qualitative and quantitative. The qualitative data were based on audiovisual recordings of the students as they refereed matches and verbalization data from self-confrontation interviews; these data were used to document the students’ courses of experience during the activity period under study. The quantitative data were collected using two questionnaires, one to assess the determinants of motivation and the other to assess self-determined motivation.
Results and discussion: The qualitative analysis highlighted three typical student involvements: fulfilling the role of referee, getting help, and occasionally dropping out of the role. The quantitative analysis revealed that the students in the social role of referee mainly expressed amotivation, external regulation, and intrinsic motivation toward knowledge and accomplishment.
The results are discussed around two major points: (1) the students’ strategies of alternation from which their refereeing activity emerged and (2) proposals for PE teacher interventions. 相似文献
A growing body of research indicates that transformational leadership affects teachers’ commitment to their school. The present study aims to investigate the processes explaining this effect at the organisational level. Using a sample of 660 teachers within 50 primary French‐speaking Belgian schools, the authors test a model hypothesising that the impact of the school principal's transformational leadership (as an organisational‐level construct) on teacher commitment to school is mediated by school culture strength (cognitive pathway) and teacher collective efficacy beliefs (motivational pathway). Results of multilevel analyses largely support the theoretical model, but show that schools have a limited impact on teacher commitment. 相似文献
The amount of health information available on the Internet is considerable. In this context, several health gateways have been developed. Among them, CISMeF (Catalogue and Index of Health Resources in French) was designed to catalogue and index health resources in French. The goal of this article is to describe the various enhancements to the MeSH thesaurus developed by the CISMeF team to adapt this terminology to the broader field of health Internet resources instead of scientific articles for the medline bibliographic database. CISMeF uses two standard tools for organizing information: the MeSH thesaurus and several metadata element sets, in particular the Dublin Core metadata format. The heterogeneity of Internet health resources led the CISMeF team to enhance the MeSH thesaurus with the introduction of two new concepts, respectively, resource types and metaterms. CISMeF resource types are a generalization of the publication types of medline. A resource type describes the nature of the resource and MeSH keyword/qualifier pairs describe the subject of the resource. A metaterm is generally a medical specialty or a biological science, which has semantic links with one or more MeSH keywords, qualifiers and resource types. The CISMeF terminology is exploited for several tasks: resource indexing performed manually, resource categorization performed automatically, visualization and navigation through the concept hierarchies and information retrieval using the Doc'CISMeF search engine. The CISMeF health gateway uses several MeSH thesaurus enhancements to optimize information retrieval, hierarchy navigation and automatic indexing. 相似文献
