The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lateralis (VL) muscle was measured continuously. During walking, lower [tHb] was observed at 1 min in Cold 1 and Cold 2 vs. Neutral (P?0.05). Lower [diffHb] was seen at 1 and 10 min in Cold 2 vs. Neutral by 13.5 ± 1.2 µM and 15.3 ± 1.4 µM and Cold 1 by 10.4 ± 3.1 µM and 11.1 ± 4.1 µM, respectively (P?0.05). During running, [tHb] was lower in Cold 2 vs. Neutral at 10 min only (P = 0.004). [diffHb] was lower at 1 min in Cold 2 by 11.3 ± 3.1 µM compared to Neutral and by 13.5 ± 2.8 µM compared to Cold 1 (P?0.001). Core tissue cooling, prior to exercise, induced greater deoxygenation of the VL muscle during the early stages of exercise, irrespective of changes in blood volume. Skin cooling alone, however, did not influence deoxygenation of the VL during exercise.     

Biomechanical loading in the triple jump

The triple jump is a demanding field event in which a jumper must tolerate extremely high impact forces while maintaining high horizontal speed. The present study was designed to clarify the mechanical loading characteristics and the role of neuromuscular function in the triple jump. Seven national triple jumpers (4 males, 3 females) volunteered to perform 3-6 jumps. The mean best performances were 14.32+/-0.45 m and 11.90+/-0.28 m for males and females, respectively. The three longest triple jumps for each jumper were selected for final analysis. The mean contact times were 0.139 s (hop), 0.157 s (step) and 0.177 s (jump). The largest ground reaction forces were observed in the step (15.2 times body weight), while the highest peak pressures were recorded under the heel and forefoot. The plantar pressure of the lateral side of the forefoot was highly related to the length of the triple jump (P < 0.05-0.01). In addition, electromyograms of both legs Suggested that mechanical loading places high demands on the neuromuscular system, as characterized by the high rate of activation in the pre-activity phase followed by high eccentric activity. Thus, the high activities of the gastrocnemius, vastus lateralis and hip extensor muscles seem to play an important role in preventing unnecessary yielding of the jumper during the braking phase.     

Swedish full text retrieval: Effectiveness of different combinations of indexing strategies with query terms

In this paper, which treats Swedish full text retrieval, the problem of morphological variation of query terms in the document database is studied. The Swedish CLEF 2003 test collection was used, and the effects of combination of indexing strategies with query terms on retrieval effectiveness were studied. Four of the seven tested combinations involved indexing strategies that used normalization, a form of conflation. All of these four combinations employed compound splitting, both during indexing and at query phase. SWETWOL, a morphological analyzer for the Swedish language, was used for normalization and compound splitting. A fifth combination used stemming, while a sixth attempted to group related terms by right hand truncation of query terms. The truncation was performed by a search expert. These six combinations were compared to each other and to a baseline combination, where no attempt was made to counteract the problem of morphological variation of query terms in the document database. Both the truncation combination, the four combinations based on normalization and the stemming combination outperformed the baseline. Truncation had the best performance. The main conclusion of the paper is that truncation, normalization and stemming enhanced retrieval effectiveness in comparison to the baseline. Further, normalization and stemming were not far below truncation.     

科学意识形态述评

在科学及技术成为现代文化核心的今天,人们也看到了科学及技术所带来的种种弊病。如何才能按人们的愿望更成功地驾驭科学及技术,使之造福人类,促使人们对以科学及技术为核心的现代文化的反思,提升到进入意识形态的理论层次,并展开讨论。从意识形态角度对科学进行反思,对于我国现代化建设具有的重要意义。进一步思考,在世界文化大碰撞中,中国的文化将为人类文化的走向作出什么贡献。     

The Effect of Differential Motivation on IRT Linking

The purpose of this study was to investigate whether simulated differential motivation between the stakes for operational tests and anchor items produces an invalid linking result if the Rasch model is used to link the operational tests. This was done for an external anchor design and a variation of a pretest design. The study also investigated whether a constrained mixture Rasch model could identify latent classes in such a way that one latent class represented high‐stakes responding while the other represented low‐stakes responding. The results indicated that for an external anchor design, the Rasch linking result was only biased when the motivation level differed between the subpopulations to which the anchor items were administered. However, the mixture Rasch model did not identify the classes representing low‐stakes and high‐stakes responding. When a pretest design was used to link the operational tests by means of a Rasch model, the linking result was found to be biased in each condition. Bias increased as percentage of students showing low‐stakes responding to the anchor items increased. The mixture Rasch model only identified the classes representing low‐stakes and high‐stakes responding under a limited number of conditions.     

Supporting the professional development of teacher educators in a productive way

This study reports on what 13 teacher educators going through a procedure to become registered as a teacher educator in 2011–2012 learned, what goals they formulated for their further professional development and what activities they planned to achieve these goals. The methods used in this study are mainly the same as were used at the time the first cohort went through the registration procedure in 2002. The 2012 cohort participated in a supportive programme, whereas the 2002 cohort did not. This enables a comparison of the results of both studies and thus some insight into the possible benefits of integrating a registration procedure with a supportive programme for the professional development of teacher educators.     

In-service teacher training to provide psychosocial support and care in high-risk and high-need schools: school-based intervention partnerships

This article uses a South African case study to argue that postcolonial, emerging economy societies in transition often contain schools characterised as high risk and high need. Such schools require teachers to adapt to roles other than facilitating learning, such as psychosocial support and care, and which requires additional professional development. In the absence of structured teacher professional development programmes, alternatives are required to assist teachers. The paper describes a nine-year partnership between higher education researchers and teachers in high-risk and high-need schools in three South African provinces. The participatory reflection and action (PRA) study served as platform for a school-based intervention to assist in-service teachers to adapt to their additional responsibilities. Thematic analysis was used to identify the ways in which teachers’ adaptation to high risk benefitted from the programme, and self-determination theory is used to argue for a dynamic and interconnected relationship between the teachers’ demonstrated pathways to psychosocial support and care. The article argues that in socio-politically transforming societies where need is high for in-service teacher training and formal structures for teacher professional development may be limited, partnerships between researchers and teachers appear to be useful platforms for school-based interventions to support teacher resilience.     

Neural Correlates of Self and Its Interaction With Memory in Healthy Adolescents

Adolescence is marked by the development of personal identity and is associated with structural and functional changes in brain regions associated with Self processing. Yet, little is known about the neural correlates of self‐reference processing and self‐reference effect in adolescents. This functional magnetic resonance imaging study consists of a self‐reference paradigm followed by a recognition test proposed to 30 healthy adolescents aged 13–18 years old. Results showed that the rostral anterior cingulate cortex is specifically involved in self‐reference processing and that this specialization develops gradually from 13 to 18 years old. The self‐reference effect is associated with increased brain activation changes during encoding, suggesting that the beneficial effect of Self on memory may occur at encoding of self‐referential information, rather than at retrieval.     

The Joinville School and the Institutionalization of a French-Style Physical Education, 1852–1939

Since the mid-nineteenth century, the Joinville School in France has worked to promote an innovative method of physical education, the French method, which was strongly marked by ideological and geopolitical challenges. Most of the French actors, whether they be military, doctors, scientists, or teachers, fought to defend France on the move. Physical education and its scholastic responsibility thus represented an original means to serve the national community and to give the country the necessary influence it required on the political and cultural international scene. If during the Second Empire, the Joinville School participated in the development of the physical instruction of French troops, during the third Republic, this officers' training school expanded the promotion of its method for physical education in schools. Among the challenges of this strategy, the actors for French physical education were faced with the organization of a common national teaching method as additional support for the promotion of a method that bore the mark of an eclectic philosophy. Until World War II, the Joinville School was a center for innovation that would spread practical physical education throughout France and Europe.     

MEMS热驱动可变电容的有限元模拟研究

设计了一种热致驱动MEMS可变电容器,其主要结构由固定于衬底的下极板和可上下活动的上极板组成;上极板由四个对称结构的热驱动器驱动,每个热驱动器主要包括两根冷臂和两根加热臂。通过输入电压,热驱动器发生形变,带动电容器的上极板向上运动,从而使电容值减小。有限元方法模拟结果表明：在4V驱动电压下,加热臂长为150μm时,电容值变为原先的0.3倍;而加热臂长为300μm时,电容值只有原先的1/10。