Differences In Lower Limb Kinetics In College Age Female Gymnasts To Coaches’ Perceived Efficiency In A Specific Counter Movement Jump Technique

This thesis reports the results of a quantitative research project which examined kinetics of female collegiate gymnasts aged 18 to 21 performing a ‘punching’ counter-movement jump (CMJ) technique that is taught and required for exemplar scoring during NCAA competition. Twelve female gymnasts were recruited from the competitive team at Illinois State University. Participation was voluntary and athletes were not compensated. Each gymnast performed 8 punch-CMJ trials without coaching instruction except to perform a punching CMJ. The method of performing this CMJ began by stepping off from a 33 cm elevation, ‘punching’ off the force plates, and finishing with a landing on the same force plates, one foot on each plate. A 3-dimensional Vicon motion analysis system was used to collect kinematic data, and one force plate was used to collect ground reaction forces under the left limb during the jumps. Vertical ground reaction force and joint kinetics of the ankle of the left leg were analyzed using inverse dynamic analysis technique. The trials were observed and rated categorically from bad, not very good, decent, good and very good by a professional gymnastics coach. Utilizing an ANOVA, differences between the categories for peak left ankle power (Lankle) and the peak left vertical ground reaction forces (LVGRF) were observed with a clear trend in increasing peak ankle power and increasing peak LVGRF with more efficient punch movement patterns. This indicates that coaching athletes to master this movement in order to perform it with high quality, will subject the ankle to higher ankle power, and higher LVGRF at impact

Team Familiarity and Productivity in Cardiac Surgery Operations: The Effect of Dispersion, Bottlenecks and Task Complexity

Fluid teams are commonly used by a variety of organizations to perform similar and repetitive yet highly critical and knowledge-intensive tasks. Such teams operate for a limited time, after which they dissolve and some of their members may work together again as part of another team. Using a granular dataset of 6,206 cardiac surgeries from a private hospital in Europe over seven years, our study offers a new and detailed account of how team familiarity (i.e., shared work experience) influences team productivity. We highlight the role of nuanced team composition dynamics beyond average team familiarity. We observe that teams with high dispersion of pairwise familiarity exhibit lower team productivity, and the existence of a "bottleneckpair" may significantly hinder overall knowledge transfer capability, thus, productivity of fluid teams. In addition, we find that the higher the percentage of familiarity gained from complex tasks, the higher the productivity of the team. Finally, our results suggest that the positive effect of average team familiarity on productivity is enhanced when performing more complicated tasks. Our study provides new operational insights to improve productivity of fluid teams with better team composition strategies

Lifestyle and physical activity patterns of Greek children : the applicability of a school based intervention programme.

The promotion of an active lifestyle has become a priority in Western societies and school plays a dominant role. The primary objectives of this thesis were i) to examine the lifestyle and physical activity (PA) patterns of a sample of Greek children and ii) to examine the applicability of a school based intervention programme in promoting PA and sport participation. For the purposes of this study the Physical Activity and Lifestyle Questionnaire (PALQ) was developed and examined for its validity and reliability to assess habitual PA of Greek students. Afterwards, a need analysis was carried out in a) a cross sectional sample of 911 students from an urban area (11, 14 and 17 years olds, b) 103 elementary and secondary PE teachers, and c) 17 schools. The students answered the PALQ in order to depict a profile of their lifestyle and PA patterns. The teachers answered a questionnaire in order to evaluate their knowledge, attitudes and self­efficacy towards teaching health related exercise (HRE). A checklist has been used in order to establish the nature and extent of PA promotion in a sample of elementary and secondary schools. The results showed that: a) a large proportion of students adopted a sedentary lifestyle and were inadequately active to obtain health benefits, b) teachers' had limited ability in promoting effectively HR issues, and c) schools provided limited sport programmes and facilities. The overall finding of the need analysis justified the need for intervention and advocated the adoption of an ecological approach to promote PA Based on the Active School initiative (Almond & McGeorge, 1995), a school based intervention programme has been set up in order to a) promote students' participation in physical activity and sport and to enhance their knowledge on health related (HR) issues, b) increase teachers' knowledge and effectiveness on teaching HR exercise. The decisions about the intervention contents and priorities were based on the findings of the need analysis taking into consideration the cost and the resources. The intervention strategy and the implementation process focused on: a) the teachers' training, b) the creation and the provision of the necessary resources (PE curriculum, a handbook and a CD-Rom for the teachers and two books for the students), c) the creation of a positive and enjoyable learning PE environment, and d) the co-operation between school and out of school health and sport alliances. The intervention programme was applied in 9 elementary and 5 secondary schools for a period of six months and involved 15 PE teachers. A quasi-experimental design with a control group was applied (experimental group N1=699 and control group N2=213). A number of different parameters were estimated at the beginning, during and at the end of the program. The intervention process was monitored on a weekly basis by the author and the school teachers. The effectiveness of the intervention was evaluated in terms of: a) students' behaviour, fitness, self-efficacy, intrinsic motivation, intentions, and attitudes related to PA, b) teachers' knowledge, attitudes and self-efficacy on teaching HR issues, and c) the broader impact of the programme on the school ethos. The intervention implementation and effectiveness was also assessed by an external evaluator. The overall purpose of the intervention was to examine the applicability of promoting PA throughout school environment by creating an innovative and realistic framework for school physical education lesson. The findings of this thesis were very encouraging. Significant differences have been observed in most of the evaluated variables both, for students (fitness, attitudes, self-efficacy, PA level), for teachers (knowledge) and schools' ethos. However, this pioneer study revealed a number of key considerations and issues in designing intervention programmes to promote PA throughout schools in urban areas

Interdisciplinarity in Data Analysis Through the Primary School Textbooks in Greece and Singapore

Data analysis is one of the most popular fields of mathematics and includes statistics and probability. These two mathematical domains are some of the most well-known, influencing everyday life and the various sciences. Their teaching lays the foundation for primary education and culminates in secondary education. Probability and statistics are necessary for today and the future of several professions. This research attempts to highlight the multidisciplinary character of these two disciplines through the textbooks of primary education in Greece and Singapore. It aims to highlight the dependence of mathematics teaching on interdisciplinarity through textbooks. The textbook analysis was chosen because books offer varied learning opportunities. The researchers selected the books, partaking in the comparative analysis.  After defining the basic principles dividing lines for the differentiation of the exercises, the analysis was conducted. It included two stages. In the first stage, the activities of the books were examined in their framework application. Then, their interdisciplinary character was accentuated in the scientific field. The results reveal a substantial dependence of data analysis on interdisciplinarity. More interesting is that the distribution of interdisciplinary exercises is prevalent in the scientific milieus

Task Variety in Professional Service Work: When It Helps and When It Hurts

In a wide range of professional service firms, individuals perform a variety of tasks which are highly cognitive and knowledge intensive yet repetitive in nature, providing significant opportunities for learning. In addition, individuals in such environments tend to enjoy considerable discretion in managing when and how they perform their tasks. In light of these observations, we investigate task allocation and timing strategies that may enhance or inhibit learning and productivity for professional service workers. Specifically, we focus on the role of task variety. We use a detailed dataset of 3273 coronary artery bypass surgeries in a private European hospital over 7 years to examine the effect of concurrent and non‐concurrent exposure to task variety on learning and productivity on a focal task. We find that while concurrent exposure to variety has a positive impact on focal productivity, non‐concurrent exposure to variety has a negative impact on it. Our results also suggest that short‐term exposure to variety amplifies these relationships

Proof complexity of positive branching programs

We investigate the proof complexity of systems based on positive branching programs, i.e. non-deterministic branching programs (NBPs) where, for any 0-transition between two nodes, there is also a 1-transition. Positive NBPs compute monotone Boolean functions, just like negation-free circuits or formulas, but constitute a positive version of (non-uniform) NL, rather than P or NC1, respectively. The proof complexity of NBPs was investigated in previous work by Buss, Das and Knop, using extension variables to represent the dag-structure, over a language of (non-deterministic) decision trees, yielding the system eLNDT. Our system eLNDT+ is obtained by restricting their systems to a positive syntax, similarly to how the 'monotone sequent calculus' MLK is obtained from the usual sequent calculus LK by restricting to negation-free formulas. Our main result is that eLNDT+ polynomially simulates eLNDT over positive sequents. Our proof method is inspired by a similar result for MLK by Atserias, Galesi and Pudl\'ak, that was recently improved to a bona fide polynomial simulation via works of Je\v{r}\'abek and Buss, Kabanets, Kolokolova and Kouck\'y. Along the way we formalise several properties of counting functions within eLNDT+ by polynomial-size proofs and, as a case study, give explicit polynomial-size poofs of the propositional pigeonhole principle.Comment: 31 pages, 5 figure

Numerical investigation of the effects of tunnelling on existing tunnels

Construction of the Crossrail tunnels just beneath the existing Central line tunnels at the northern side of Hyde Park provided the impetus for this paper. A basic three-dimensional (3D) finite-element (FE) model was developed to study a general case of a new tunnel (NT) crossing perpendicularly below an existing tunnel (ET). A series of 3D FE analyses was carried out and the results presented in this paper reveal some of the interaction effects. Changes in hoop forces, bending moments and lining deformations of the ET due to excavation of the NT are discussed. Conclusions are drawn about how the relative position of the excavation face of the NT in relation to the ET's axis affects the latter's behaviour. Cross-sectional and longitudinal deformations of the ET are discussed, leading to recommendations for field monitoring of similar interaction cases. Two parametric studies were also carried out to quantify the effects of the magnitude of the earth pressure balance machine face pressure and the longitudinal stiffness of the ET on the predicted behaviour of the ET due to construction of the NT

The use of kinematic hardening models for predicting tunnelling-induced ground movements in London Clay

The use of a kinematic hardening soil model for predicting short- and long-term ground movements due to tunnelling in London Clay is investigated. The model is calibrated against oedometer and triaxial tests on intact samples from different units of the London Clay. The calibrated model is then used in finite-element analysis to simulate the field response at St James's Park during excavation of the Jubilee Line Extension tunnels. The finite-element predictions compare well with the available field monitoring data. The importance of using consistent initial conditions for this complex boundary value problem in conjunction with the model parameters selected is highlighted. The stiffness response of different regions of the finite-element mesh indicates that the rate at which the stiffness degrades and the stiffness response further away from the tunnel boundary affect the short-term predictions significantly. The long-term predictions confirm that the compression characteristics of the soil control the magnitude of the consolidation settlements and its permeability the shape of the long-term settlement profiles