The effect of normal load force and roughness on the dynamic traction developed at the shoe–surface interface in tennis

During tennis-specific movements, such as accelerating and side stepping, the dynamic traction provided by the shoe–surface combination plays an important role in the injury risk and performance of the player. Acrylic hard court tennis surfaces have been reported to have increased injury occurrence, partly caused by increased traction that developed at the shoe–surface interface. Often mechanical test methods used for the testing and categorisation of playing surfaces do not tend to simulate loads occurring during participation on the surface, and thus are unlikely to predict the human response to the surface. A traction testing device, discussed in this paper, has been used to mechanically measure the dynamic traction force between the shoe and the surface under a range of normal loading conditions that are relevant to real-life play. Acrylic hard court tennis surfaces generally have a rough surface topography, due to their sand and acrylic paint mixed top coating. Surface micro-roughness will influence the friction mechanisms present during viscoelastic contacts, as found in footwear–surface interactions. This paper aims to further understand the influence micro-roughness and normal force has on the dynamic traction that develops at the shoe–surface interface on acrylic hard court tennis surfaces. The micro-roughness and traction of a controlled set of acrylic hard court tennis surfaces have been measured. The relationships between micro-roughness, normal force, and traction force are discussed.     

The effects of surface traction characteristics on frictional demand and kinematics in tennis

The interaction between footwear and surfaces influences the forces experienced by tennis players. The purpose of this study was to investigate traction demand and kinematic adaptation during tennis-specific movements with changes in traction characteristics of surfaces. We hypothesised that players would increase the utilised coefficient of friction (horizontal to vertical ground reaction force ratio) when the shoe surface combination had a high coefficient of friction and flex their knee after contact to facilitate braking. Eight participants performed two separate movements, side jump out of stance and running forehand. Ground reaction force was measured and three-dimensional kinematic data were recorded. Clay surface and cushioned acrylic hard court (low vs. high shoe–surface friction) were used. The peak utilised coefficient of friction was greater on clay than the hard court. The knee was less flexed at impact on clay ( ? 5.6 ± 10.2°) and at peak flexion ( ? 13.1 ± 12.0°) during the running forehand. Our results indicate that tennis players adapt the level of utilised friction according to the characteristics of the surface, and this adaptation favours sliding on the low friction surface. Less knee flexion facilitates sliding on clay, whereas greater knee flexion contributes to braking on the hard court.     

Some current issues in the administration of Australian universities

The Australian universities have entered a steady-state period in which enrolments and funding are being held with limits predetermined by government instead of being allowed to expand to levels compatible with institutional goals. A model of a university system is emerging from the recommendations of the Tertiary Education Commission (TEC), and the guidelines set by the Federal Government and the proposals of the State Governments. This model aims to be equitable, accountable, efficient and well co-ordinated but it allows for Federal and State government intrusion into areas of decision-making that the universities have traditionally regarded as their preserves for autonomous action.The Tertiary Education Commission, as the Federal system-authority, has concentrated on the evidence and the need for change in four major areas: the nature of the student population; funding and, consequently, staffing, and procedures for co-ordination and rationalization. The states have shown particular interest in the fourth area and have aligned themselves with the TEC as it has devised a series of proposals, for all four areas, which have ultimately been placed upon the universities in the amended, and sometimes more restrictive form of Federal government guidelines.An examination of the new model of university education that is taking shape and the universities' reaction to it suggests that the universities are faced with three alternatives. They can capitulate and subscribe fully to this model being formulated beyond their campuses or they can unilaterally resist its imposition. Their third option, however, involves both compromise and initiative and it is emerging as the most effective choice for survival in the steady state environment.In taking the third option, the universities will have to adopt a two-pronged approach. Firstly, they will need to anticipate and to adjust to external initiatives by shortterm tactics conducted by an efficient centralized administration. Secondly, and most importantly both the administrative and academic communities will have to accommodate these adjustments to a long-term plan that will determine the role and function of their university and, ultimately, of the entire university system of education amongst the economic, political and social realities of the late 20th century.     

Eyes wide shut: the fantasies and disavowals of education policy

ABSTRACT

This paper examines the tensions between education policy’s attachment to notions such as excellence and inclusion and its investments in managerial tropes of competition, continuous quality improvement, standards and accountability that are at odds with and which undermine its attachments. In order to explore these tensions, I draw on the psychoanalytic notion of fantasy, explained through Stanley Kubrick’s final film, Eyes wide shut. My argument is that while the individual and society are both constituted through unavoidable division, antagonism and opacity, these notions are obscured through the operations of fantasy which holds out the promise of wholeness, harmony and redemption. In particular, education serves as a key site in which these fantasmatic ideals are promoted and pursued, a claim I substantiate via an analysis of the UK government’s 2016 White Paper, Educational Excellence Everywhere. Specifically, I read the White Paper in terms of five fantasies of: control; knowledge and reason; inclusion; productivity; and victimhood. My argument is that while fantasy is an inescapable element that inevitably structures what we take to be ‘reality’, education policy might strive to inhabit fantasy differently, thereby finding ways of escaping its current mode of seeing education with eyes wide shut.     

Education,population, environment and sustainable development

It is widely acknowledged that education and training have an important role in meeting the challenges of global environmental change. This paper looks at the way global concerns have emerged and evolved in recent decades, how they are interrelated, especially the population-environment interrelationships, and at the need for sustainable development. Population and environmental education have been two distinct educational responses, both fostered by international organizations, but now they need to be linked. The paper looks at the way geography, especially population geography, may offer integrating opportunities, through its academic scope, a wide range of spatial and time scales, and a consciousness of the great diversity of cultures, economies, polities and environments.

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Zusammenfassung Es ist allgemein bekannt, daß Bildung und Ausbildung eine wichtige Rolle bei der Reaktion auf weltweite Umweltveränderungen spielen. In diesem Artikel wird erörtert, wie weltweite Probleme in den letzten Jahrzehnten entstanden sind und wie sie sich weiterentwickelt haben, wie sie unter besonderer Beachtung der Beziehungen zwischen Bevölkerung und Umwelt miteinander zusammenhängen und wie die notwendige Entwicklung unterstützt werden kann. Bevölkerungslehre und Erziehung zum Umweltbewußtsein sind zwei voneinander getrennte bildungspolitische Antworten, die beide von internationalen Organisationen gefördert werden, nunmehr aber miteinander verbunden werden sollten. Der Artikel setzt sich damit auseinander, inwieweit die Geographie, besonders die Bevölkerungslehre, durch ihre akademische Reichweite Möglichkeiten zur Integration bietet, sich mit zeit- und raumbezogenen Dimensionen befaßt und ein Bewußtsein über die große Vielfalt an Kulturen, Wirtschaftssystemen, politischen Systemen und Umgebungen schafft.

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Résumé Il est universellement reconnu que l'éducation et la formation sont indispensables pour répondre aux défis du changement global de l'environnement. Le présent article examine la manière dont les problèmes globaux ont apparu et se sont développés au cours des dernières décennies, leurs relations mutuelles, particulièrement celles entre l'environnement et la population, et la nécessité d'un développement durable. L'éducation en matière de population et l'éducation relative à l'environnement sont deux réponses éducatives distinctes, toutes deux promues par les organisations internationales, mais à présent il paraît nécessaire d'établir un lien entre elles. On analyse, par ailleurs, la manière dont la géographie, en particulier la géographie de la population, peut offrir des possibilités d'intégration, grâce à sa portée théorique, un grand nombre d'échelles spatiales et temporelles, et une connaissance de la grande diversité des cultures, économies, politiques et environnements.

     

Young adolescents' beliefs concerning menstruation

In order to explore the early socialization of attitudes and expectations about menstruation, 54 young adolescent girls (both pre- and postmenarcheal) and boys responded to a questionnaire assessing evaluative attitudes toward menstruation, expected symptomatology, perceived effects on moods and activities, and sources of information for these beliefs. The results showed that even premenarcheal girls and young boys have a reasonably well-defined and mostly negative set of attitudes and expectations. Most believed that menstruation is accompanied by physical discomforts, increased emotionality, and a disruption of activities and social interactions. Although the responses of the 3 groups were remarkably similar, premenarcheal girls had a somewhat less negative evaluation of menstruation than both postmenarcheal girls and boys. Other analysis showed that symptom expectations for "girls in general" were more severe than for selves, though these 2 sets of responses were highly correlated. On the basis of these findings and the data concerning sources of information, the possible role of socialization processes in the menstrual experience is discussed.     

Addressing the challenge of legitimate international comparisons of classroom practice

In this article, we address the choice of suitable instructional units that might serve as the basis for cross-cultural analyses of classroom practice. Our argument draws on analyses undertaken as part of the Learner's Perspective Study (LPS). The database comprised a three-camera video record of sequences of 10 consecutive lessons in each classroom, supplemented by post-lesson video-stimulated interviews with teachers and students: a total of over 180 videotaped lessons, over 50 teacher interviews and almost 400 student interviews. The results of these analyses challenge the suitability of the lesson as the unit of comparative analysis. In particular, the location of the lesson in the topic sequence is seen to be a key influence on the lesson's structure, critically affecting the teacher's deployment of the constituent activities that we have called ‘lesson events.’ The lesson event is proposed as an alternative unit of international comparative analysis of classroom practice.     

Elaborating a model of teacher professional growth

This paper details a model of teacher professional growth and relates the model to the research data on which the model is empirically founded. A key feature of the model is its inclusion of four analytic domains in close correspondence to those employed by Guskey (Educational Researcher 15(5), 1986) and others, but the model proposed in this paper identifies the specific mechanisms by which change in one domain is associated with change in another. The interconnected, non-linear structure of the model enabled the identification of particular “change sequences” and “growth networks”, giving recognition to the idiosyncratic and individual nature of teacher professional growth. One major value of a change model grounded in empirical data lies in its capacity to stimulate speculation, research and development regarding possible change mechanisms as yet unexplored and unexploited. In its current form, this model offers a powerful framework to support the analyses of those studying teacher change (or growth) and the planning of those responsible for teacher professional development.     

Behaviors of youth involved in the child welfare system

OBJECTIVE: Using data from a nationally representative panel study, the National Survey of Child and Adolescent Well-Being (NSCAW), we address the following questions: (a) What are the youth, family, community, and child welfare system risk factors that place youth (ages 11-14 years) living at home, who are referred for maltreatment, at increased risk of delinquent behaviors over time? and (b) What promotive factors at the youth, family, community, and child welfare system levels appear to minimize the risk of delinquent behaviors for these youth over time? METHODS: The study uses the NSCAW data collected at baseline (Wave 1) and 18 months later (Wave 3). The multivariate analyses were conducted using a tobit model adjusted for longitudinal data and a complex survey sample. RESULTS: Several significant risk and promotive factors were found to influence the risk of delinquent behaviors over time. Older youth were more likely to engage in delinquent behaviors than younger youth. Girls were less likely to engage in delinquent behaviors than boys. Race or ethnicity did not have a statistically significant relationship with engaging in delinquent behaviors. Compared with neglected youth, youth who were physically abused were more likely to engage in delinquent behaviors. Increases in caregiver monitoring and in the quality of relationship with caregivers were associated with decreases in delinquent behaviors. Youth at greatest risk and those who engaged in more delinquent behaviors received more child welfare services then youth who did not engage in delinquent behaviors. CONCLUSIONS: The current child welfare delivery system emphasizes provision of services to youth experiencing the more serious problems and less on preventive services. The study findings suggest that preventive services when youth first enter the child welfare system that focus on enhancing caregiver skills in building positive relationships with their youth and increased monitoring of the youth's activity may alter the pathway to delinquent behaviors for these youth.     

Individual differences in RAN and reading: a response timing analysis

Thirty 8–11‐year‐old children were administered tests of rapid naming (RAN letters and digits) and reading‐related skills. Consistent with the hypothesis that RAN predicts reading because it assesses the ability to establish arbitrary mappings between visual symbols and verbal labels, RAN accounted for independent variance in exception word reading when phonological skills were controlled. Response timing analysis of different components of RAN digits and letters revealed that neither average item duration nor average pause duration were unique predictors of reading skill. However, the number of pauses on digit naming predicted unique variance in exception word reading. Moreover, better readers paused more strategically than poorer readers (e.g. more often at the ends of lines). We suggest that rapid automatised naming may in part reflect differences in strategic control that are a result of differences in reading practice and experience.