Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions     

Andersson H  Ekblom B  Krustrup P 《Journal of sports sciences》2008,26(2):113-122

The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.  相似文献   

The audio postcard assignment: Practicing the use of descriptive language     

Kristina A. Wenzel Egan 《Communication Teacher》2018,32(3):131-135

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Estimating fat-free mass in elite-level male rowers: a four-compartment model validation of laboratory and field methods     

Kristina L. Kendall  David H. Fukuda  Parker N. Hyde  Abbie E. Smith-Ryan  Jordon R. Moon  Jeffrey R. Stout 《Journal of sports sciences》2017,35(7):624-633

The purpose of this study was to investigate the accuracy of fat-free mass (FFM) estimates from two-compartment (2C) models including air displacement plethysmography (ADP), ultrasound (US), near-infrared interactance (NIR), and the Jackson and Pollock skinfold equation (SKF) against a criterion four-compartment (4C) model in elite male rowers. METHODS: Twenty-three elite-level male rowers (mean± SD; age 24.6 ± 2.2 years; stature: 191.4 ± 7.2 cm; mass: 87.2 ± 11.2 kg) participated in this investigation. All body composition assessments were performed on the same day in random order, except for hydrostatic weighing (HW), which was measured last. FFM was evaluated using a 4C model, which included total body water from bioimpedance spectroscopy, body volume from HW, and total body bone mineral via dual-energy X-ray absorptiometry. The major findings of the study were that the 2C models evaluated overestimated FFM and should be considered with caution for the assessment of FFM in elite male rowers. Future studies should use multiple-compartment models, with measurement of TBW and bone mineral content, for the estimation of FFM.  相似文献   

Developing CM3: Maintainers' Education and Training at ABB     

Mira Kajko-Mattsson  Stefan Forssander  Gunnar Andersson  Ulf Olsson 《Computer Science Education》2013,23(1-2):57-89

A highly skilled maintainer is the most important organisational asset pivotal for achieving quality software, strategic for improving maintenance and development processes, essential for remaining competitive and critical for business survival. This requires that universities properly prepare students to enter the maintenance workforce and that maintenance organisations actively build and maintain their human knowledge and skill base. In this paper, we present Corrective Maintenance Maturity Model (CM 3): Maintainers' Education and Training – a maturity model for educating and training maintenance engineers within corrective maintenance. This model is presently being developed at ABB by the Software Maintenance Laboratory (SML). Our goal is to provide guidance to ABB and industrial organisations worldwide in the process of building or improving their most important asset – people. Each process element presented in this paper is matched against its corresponding process element at ABB. Hence, this paper may also be regarded as a report on the state of the current practice of educating and training maintainers at ABB.  相似文献   

Chemistry for whom? Gender awareness in teaching and learning chemistry     

Kristina Andersson 《Cultural Studies of Science Education》2017,12(2):425-433

Marie Ståhl and Anita Hussénius have defined what discourses dominate national tests in chemistry for Grade 9 in Sweden by using feminist, critical didactic perspectives. This response seeks to expand the results in Ståhl and Hussénius’s article Chemistry inside an epistemological community box!—Discursive exclusions and inclusions in the Swedish national tests in chemistry, by using different facets of gender awareness. The first facet—Gender awareness in relations to the test designers’ own conceptions—highlighted how the gender order where women are subordinated men becomes visible in the national tests as a consequence of the test designers internalized conceptions. The second facet—Gender awareness in relation to chemistry—discussed the hierarchy between discourses within chemistry. The third facet—Gender awareness in relation to students—problematized chemistry in relation to the students’ identity formation. In summary, I suggest that the different discourses can open up new ways to interpret chemistry and perhaps dismantle the hegemonic chemistry discourse.  相似文献   

Changes in Lithuanian Pre-school and Pre-primary Education Quality Over the Last Decade     

Ona Monkeviciene  Kristina Stankeviciene 《美中教育评论》2011,(1):119-130

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A Dual Identity Approach for Conceptualizing and Measuring Children's Gender Identity          下载免费PDF全文

Carol Lynn Martin  Naomi C. Z. Andrews  Dawn E. England  Kristina Zosuls  Diane N. Ruble 《Child development》2017,88(1):167-182

The goal was to test a new dual identity perspective on gender identity by asking children (n = 467) in three grades (M_age = 5.7, 7.6, 9.5) to consider the relation of the self to both boys and girls. This change shifted the conceptualization of gender identity from one to two dimensions, provided insights into the meaning and measurement of gender identity, and allowed for revisiting ideas about the roles of gender identity in adjustment. Using a graphical measure to allow assessment of identity in young children and cluster analyses to determine types of identity, it was found that individual and developmental differences in how similar children feel to both genders, and these variations matter for many important personal and social outcomes.  相似文献   

University physics students’ ideas of thermal radiation expressed in open laboratory activities using infrared cameras     

Jesper Haglund  Emil Melander  Matthias Weiszflog  Staffan Andersson 《Research in Science & Technological Education》2017,35(3):349-367

Background: University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation and a heat pump. Students had access to handheld infrared (IR) cameras for their investigations.

Purpose: The purpose of the research was to explore students’ interactions with reformed thermodynamics laboratory activities. It was guided by the research question: How do university physics students make use of IR cameras in open-ended investigation of thermal radiation as a phenomenon?

Sample: The study was conducted with a class of first-year university physics students in Sweden. The interaction with the activities of four of the students was selected for analysis. The four students are males.

Design and methods: We used a qualitative, interpretive approach to the study of students’ interaction. The primary means of data collection was video recording of students’ work with the laboratory activities and their subsequent presentations. The analysis focused on how IR cameras helped students notice phenomena relating to thermal radiation, with comparison to previous research on students’ conceptions of thermal radiation.

Results: When using the IR camera, students attended to the reflection of thermal radiation on shiny surfaces, such as polished metals, windows or a whiteboard and emissive properties of surfaces of different types. In this way, they went beyond using the technology as a temperature probe. Students were able to discuss merits and shortcomings of IR cameras in comparison with digital thermometers.

Conclusions: With the help of IR cameras, university physics students attend to thermal phenomena that would otherwise easily go unnoticed.  相似文献   

Reformation of VET and demands on teachers’ subject knowledge – Swedish vocational teachers’ recurrent participation in a national CPD initiative     

S. Köpsén  P. Andersson 《Journal of Education & Work》2017,30(1):69-83

This study investigates continuing professional development (CPD) of vocational teachers, with a focus on recurrent participation. Vocational teachers need to be competent as teachers and in relation to their vocational teaching subject. Reformation of Swedish vocational education in order to strengthen the working-life connection imposes demands on teachers to have up-to-date knowledge about the vocations related to their vocational subjects. To support the reform, vocational teachers have been offered to participate in a new national CPD initiative targeting their vocational competence. The study concerns participation in this initiative. Drawing on a socio-cultural perspective, vocational teachers’ CPD implies boundary-crossing between school and working-life. Theory concerning adults’ participation in education is considered relevant to understand conditions for such boundary-crossing, and learning, among vocational teachers. The article specifically investigates patterns in vocational teachers’ recurrent participation, which is expected to clarify the factors influencing further participation in professional development. The strongest predictor of recurrent participation, when adjusting for the influence of other factors, is the type of municipality that the teacher comes from, with low populated municipalities having the lowest likelihood of participation. Furthermore, recurrent participation is more likely by participating teachers from adult education or from privately owned schools, and by male teachers.  相似文献   

From Interaction to Intersubjectivity: Facilitating online group discourse processes     

Vanessa Paz Dennen  Kristina Wieland 《Distance Education》2007,28(3):281-297

This article examines the online discourse that took place in representative threads from two classes, seeking to document indicators that students did or did not engage in co‐construction of knowledge. Stahl's (2006 Stahl, G. 2006. Group cognition: Computer support for building collaborative knowledge, Cambridge, MA: MIT Press.  [Google Scholar]) social theory of computer supported collaborative learning (CSCL) is used along with discourse analysis methods to examine these course dialogues. Findings show the class that had a peer‐like, consistent facilitative instructor and discussion anchored around questions and shared artifacts was more likely to engage in discussion leading to the negotiation of knowledge and understanding. This class relied on social acknowledgements, questions, and shared exploration of perspectives and theories throughout their discussion. These elements and strategies appear to be important components that make up for lower levels of tacit understanding in online environments, thus enabling learners to interact in social learning processes. The other class, which lacked a facilitative instructor, did not have the same results. Although interaction levels were equal and students carried topical motifs such as the phrase “faster, better, cheaper” from message to message, students in this other class did not engage deeply or develop new understanding of the course material through the discussion.  相似文献