Kinematics and kinetics of handcycling propulsion at increasing workloads in able-bodied subjects

In Paralympic sports, biomechanical optimisation of movements and equipment seems to be promising for improving performance. In handcycling, information about the biomechanics of this sport is mainly provided by case studies. The aim of the current study was (1) to examine changes in handcycling propulsion kinematics and kinetics due to increasing workloads and (2) identify parameters that are associated with peak aerobic performance. Twelve non-disabled male competitive triathletes without handcycling experience voluntarily participated in the study. They performed an initial familiarisation protocol and incremental step test until exhaustion in a recumbent racing handcycle that was attached to an ergometer. During the incremental test, tangential crank kinetics, 3D joint kinematics, blood lactate and ratings of perceived exertion (local and global) were identified. As a performance criterion, the maximal power output during the step test (P_max) was calculated and correlated with biomechanical parameters. For higher workloads, an increase in crank torque was observed that was even more pronounced in the pull phase than in the push phase. Furthermore, participants showed an increase in shoulder internal rotation and abduction and a decrease in elbow flexion and retroversion. These changes were negatively correlated with performance. At high workloads, it seems that power output is more limited by the transition from pull to push phase than at low workloads. It is suggested that successful athletes demonstrate small alterations of their kinematic profile due to increasing workloads. Future studies should replicate and expand the test spectrum (sprint and continuous loads) as well as use methods like surface electromyography (sEMG) with elite handcyclists.     

Soziale Unterstützung beim Berufseinstieg ins Lehramt

This study investigates the support that novice teachers receive from their mentors and peers during the teacher induction phase in Germany. It examines the relationship between the support of these two groups and the development of new teachers’ professional competencies. The sample comprises 551 novice teachers in mathematics, who were surveyed twice within one year during their induction period. Results show that both mentors and peers are perceived as providing important support, but that the two groups support different aspects of teaching competencies. Structural equation models indicate that informational and emotional support provided by mentors is associated with an increase in the teachers’ self-efficacy beliefs and a decline in their emotional exhaustion, whereas the support of peers has both positive and negative effects.     

The Differential Effects of Direct Address on Parasocial Experience and Identification: Empirical Evidence for Conceptual Difference

Whereas parasocial experience is conceptualized as imagined interaction identification is defined as the merging of one’s identity with a character’s. Thus, having a character face the camera and directly address viewers should increase the sense of parasocial experience but not affect the intensity of identification. An experiment compared the levels of parasocial experience and identification among viewers of clips from the show House of Cards that included or omitted direct address tested this prediction. Results provide support for the previously theorized conceptualdistinction between parasocial experience and identification.     

Joining forces for public value creation? Exploring collaborative innovation in smart city initiatives

Creating public value is a key goal of public administrations, both in their daily business and in the growing field of smart government and smart cities, which focuses on IT-enabled innovations in the public sphere. However, many public administrations still struggle with such innovations due to complex technologies, high investments, and the numerous stakeholders involved. To address this issue, some local governments in continental Europe have turned to collaborative innovation approaches, partnering with (semi-)public utility companies in the hope that their additional innovation assets will boost innovativeness. Nevertheless, it remains unclear how exactly such collaborations should be governed to ensure that the focus remains on creating public value, as utility companies may have their own agendas. To explore this question, we conducted a comparative case study in the context of smart city initiatives with four cases in Swiss local governments. Drawing on agency and stewardship theory, we then propose a model of public-value-focused collaborative innovation, enabling us to explore various collaboration characteristics and their effects on public value creation. Our findings suggest that both agency- and stewardship-based collaborations increase innovativeness. However, while agency collaborations tend to produce smart city innovations that mainly serve the utility companies' business interests, stewardship relationships lead to innovations that are focused more on public value creation. As such, our study extends the literature on the effects of collaborative innovation on public value, and it provides practical recommendations on how such collaborative innovation should be designed.     

Towards the integration of culture into the Unified Theory of Acceptance and Use of Technology

Educational technology is increasingly used in multicultural contexts and across national cultures. Educational technology users with different national and professional backgrounds may, however, exhibit different attitudes towards technology. Previous research provides isolated evidence of the relationship between learning technology acceptance and culture, and so an overall picture is missing. Therefore, this study attempts to integrate culture (sensu Hofstede) into an established technology acceptance model (ie, Venkatesh's Unified Theory of Acceptance and Use of Technology, UTAUT). Examining a large sample (n = 2866) of learning technology users from Germany and Romania by means of questionnaire survey, we investigate the differences in culture and technology acceptance between sample subgroups. The collected data reveal the presence of cultural differences both between countries and between professions. In line with previous research, these differences are associated with dissimilar acceptance profiles, ie, different values of acceptance variables and of path coefficients between them. Based on the findings, this study makes headway in cross‐cultural research by proposing an extended model of UTAUT—one which integrates three of Hofstede's culture dimensions. As a practical implication, national and professional culture may shape computer‐based learning environments.     

酪蛋白磷酸肽-无定形磷酸钙、不同玷污层的处理和储存时间对牙本质粘接的影响(英文)

研究目的:评价含有酪蛋白磷酸肽-无定形磷酸钙(CPP-ACP)的再矿化剂Tooth Mousse(TM)的使用、不同玷污层的处理以及样本储存时间对牙本质粘接微拉伸性能的影响。研究方法:将牙本质样本分成保留玷污层组和用15%乙二胺四乙酸(EDTA)处理90秒去除玷污层组。每组根据是否使用TM处理再分亚组。每个亚组分别用三种不同的粘结剂(两步法自酸蚀Clearfil SE Bond(CSE)、一步法自酸蚀G-Bond(GB)和全酸蚀Adper Single Bond 2(SB))与牙本质样本粘接,分别经过3天和6个月的去离子水储存。样本进行切割微拉伸测试并通过扫描电镜分析断裂界面模式。重要结论:经过再矿化剂TM预处理,可以减少牙齿的敏感性,并且对于这三种粘结系统经过长时间储存后的粘结性能没有影响。EDTA的处理对于长期储存的粘结性能没有显著影响。额外的TM和EDTA对短期(3天)粘接力会有效应,但对长期(6个月)的粘接力没有影响。     

Identification of Core Competencies for an Undergraduate Food Safety Curriculum Using a Modified Delphi Approach

Identification of core competencies for undergraduates in food safety is critical to assure courses and curricula are appropriate in maintaining a well‐qualified food safety workforce. The purpose of this study was to identify and refine core competencies relevant to postsecondary food safety education using a modified Delphi method. Twenty‐nine experts representing food safety professionals in academia, government, and industry were given 2 rounds of questionnaires that specified initial food safety competencies, core domains, and subdomains. Competencies were defined as a set of skills, knowledge, and abilities that correlate to success of a trainee. The framework for which competencies were classified consisted of (1) core domains, defined as broad food safety subjects; and (2) subdomains, or more specific food safety subjects. The expert panel used a 5‐point Likert scale with an acceptance criterion, or consensus, of 75%, with a rating of “4” or greater. After 2 rounds of questionnaires and revisions from the expert panel, 5 core domains were established: (1) Food Production, Manufacturing, Retail, and Consumer; (2) Foodborne Hazards; (3) Public Health; (4) Legislation and Policy; and (5) Communication and Education. Specific responses from the experts highlighted areas in which further curriculum revision would be beneficial. This study provides a framework for the development of a vetted, standardized undergraduate food safety curriculum. The Delphi method, with its inclusion of professionals representing various sectors of food safety, provided relevant perspectives for curriculum design, and also allowed participants the opportunity to contribute to the education of future food safety professionals.     

Images of the Body from Popular Culture: Engaging Adolescent Girls in Critical Inquiry

The purpose of this paper is to highlight how I use images from teen magazines to engage girls in critical inquiry about the body. This process is about co-constructing bodily knowledge and reflecting critically on this knowledge. The analysis is broken into three main parts: (a) tapping girls' interests; (b) helping girls name how they experience their bodies; and (c) using images to critique dominant stories of the body. Within each of these sections, I will foreground the process by looking at the curricular tasks as well as the verbal engagement through which the girls and I negotiated the tasks together. The data are used to illustrate the pedagogical possibilities of engaging girls in critical inquiry on body. I conclude the paper by discussing the pedagogical possibilities for studying the body with adolescent girls that emerged and reflect critically on the struggles involved in the process of engaging girls in critical inquiry.     

Accelerometry to Assess Preschooler's Free-Play: Issues with Count Thresholds and Epoch Durations

This study examines the utility of current accelerometer threshold definitions and epoch durations for physical activity intensity classification in preschool-aged children. Using video footage of children engaged in active play, directly observed 1-sec epoch physical activity intensity scores were derived from a modified version of the Children's Activity Rating Scale, averaged into 15-sec epochs (corresponding to the accelerometer scale), and compared to accelerometer-measured classifications. Overall, 6,540 individual 1-sec epochs were captured and classified from six children, yielding 429 time-matched 15-sec epoch physical activity intensity classifications from both methods. Children participated in 25 distinct physical activity behaviors and spent 75% of free-play in one intensity level for ≤5 sec. The maximum amount of time spent participating in an activity prior to changing activity intensity was 98 sec. Agreement between methods was generally poor (overall: κ = .22; child range: κ = .00 to .66), and the difference between methods was significantly asymmetrical (McNemar's test overall: p = .01). Accelerometer thresholds and epoch durations used to classify preschoolers' physical activity intensity yielded biased estimates in the current study. Further investigation is necessary to establish optimal physical activity measurement methods with this population.