A full body musculoskeletal model based on flexible multibody simulation approach utilised in bone strain analysis during human locomotion

Load-induced strains applied to bone can stimulate its development and adaptation. In order to quantify the incident strains within the skeleton, in vivo implementation of strain gauges on the surfaces of bone is typically used. However, in vivo strain measurements require invasive methodology that is challenging and limited to certain regions of superficial bones only such as the anterior surface of the tibia. Based on our previous study [Al Nazer et al. (2008) J Biomech. 41:1036–1043], an alternative numerical approach to analyse in vivo strains based on the flexible multibody simulation approach was proposed. The purpose of this study was to extend the idea of using the flexible multibody approach in the analysis of bone strains during physical activity through integrating the magnetic resonance imaging (MRI) technique within the framework. In order to investigate the reliability and validity of the proposed approach, a three-dimensional full body musculoskeletal model with a flexible tibia was used as a demonstration example. The model was used in a forward dynamics simulation in order to predict the tibial strains during walking on a level exercise. The flexible tibial model was developed using the actual geometry of human tibia, which was obtained from three-dimensional reconstruction of MRI. Motion capture data obtained from walking at constant velocity were used to drive the model during the inverse dynamics simulation in order to teach the muscles to reproduce the motion in the forward dynamics simulation. Based on the agreement between the literature-based in vivo strain measurements and the simulated strain results, it can be concluded that the flexible multibody approach enables reasonable predictions of bone strain in response to dynamic loading. The information obtained from the present approach can be useful in clinical applications including devising exercises to prevent bone fragility or to accelerate fracture healing.

The activities and impacts of part-time employment on full time undergraduate students in property and construction courses in Australia

This paper examines the extent of part-time employment of undergraduate students enrolled in property and construction related courses in five universities across Australia. Forty five percent of the students responded to a questionnaire on their part-time work. Past research reveals that there is need for a more accurate understanding as to why students seek part-time work to the extent that they do and that working long hours has a negative effect on the study patterns of undergraduate students. Increased employer work demands results in less time available for study and an inability to attend lectures because of work. There is growing concern that students are increasingly disinterested in connecting with the broader and total university experience and are instead, seeking to adopt a minimalist approach to education.

Analysis of current research for Property and construction students’ results reveals that students are working on average 18 hours per week during semester time. The students therefore appear to be working beyond what is considered beneficial to their studies, although their contextual understanding and work ethic improves.

The paper concludes with some approaches that could re- engage students into the learning process. It may be helpful to develop a partnership between the University and the industry thereby providing work experience that complements the program of study. Otherwise students may not get the range of experience they need and may struggle to find the linkages between theory and practice.

Part-time employment trends for full-time undergraduate property and construction students : results of a two year sequential investigation

This paper reports on the initial findings of an investigation into the experiences and part-time work practices of undergraduates enrolled in the Bachelor of Property and Construction (BPC) and combined degree courses at the University of Melbourne. Initial data was collected from final year students during 2001 and for all four years of the course in 2002. The results suggest that students in earlier years of the course are more likely to work in non-industry (casual) related employment and work fewer hours. Students in later years of the BPC course are more likely to work in jobs in the construction industry and also to work longer hours than those in earlier years. An analysis of final year students shows that the students employed by contracting organisations work significantly more hours than students employed by other types of organisations including architectural practices. The consequences of part-time semester employment on academic performance and students' well-being are considered and proposals are put forward as to how to better manage the industry experience-University relationship.

Double-layer and hydration forces measured between silica sheets subjected to various surface treatments

Force measurements between silica surfaces in aqueous solutions of NaCl are reported. Silica is prepared with one of three surface treatments: (i) flaming, (ii) exposure to steam for 150 h, and (iii) brief exposure to ammonia vapor. Analysis of electrical double-layer interactions indicates that the surface density of silanol groups increases with steam treatment, and that exposure to ammonia etches the surface slightly and renders it porous. The force at short range is dominated by a strong repulsion which is attributed to hydration of the surface. The hydration component of the force is not significantly affected by the surface treatments, nor by electrolyte concentration over the range investigated (up to 0.1 M).

Training patterns and negative health outcomes in triathlon : longitudinal observations across a full competitive season

AIM: Despite heavy training requirements, triathlon is a sport that is rapidly increasing in popularity. Yet, there is limited research detailing the relationship between training, the incidence of injuries and illness, psychological stress, overtraining and athlete burnout amongst triathletes. Six hypotheses relating inter-individual differences to training factors were generated to evaluate change in self-reported measures of these negative health outcomes over a training year.

METHODS: Thirty, well-trained, triathletes (males n=20: age=27.1±9.1 years and females n=10: age=27.4±6.6 years) from a local triathlon club participated in this study. The study commenced during pre-season training, and involved weekly monitoring of each athlete until the end of the competitive season 45 weeks later. Linear Mixed Modelling was used for the analysis.

RESULTS: Signs and symptoms of injury and illness (SAS) were significantly associated with increases in training factors (P≤0.05); however, greatest impact on SAS was produced by psychological stressors (P≤0.001). Common symptoms of overtraining were significantly affected by increases in exposure to both training and psychological stressors (P≤0.05). Mood disturbance was not significantly affected by training factors (P>0.05) but rather increases in psychological stressors (P≤0.001). Finally, each of the three athlete burnout subscales were significantly affected by both psychological (P≤0.001) stressors as well as varying combinations of training factors (P≤0.05).

CONCLUSIONS: Exposure to stressors (either training or psychological) had significant effects on all negative health outcomes assessed.

(Electronic music) beginnings (full length)

This is an optimistic, full length pop instrumental featuring piano, dub-step styled drums, synth bass, muted trumpet, Hollywood styled strings and vibraphone. The break is touched with the melancholy.

(Positive electronic music) mighty boom (full length)

An uplifting, energetic dance styled composition with dirty synth, booming drums, piano and arpeggios.

Ambient thing full length

Ambient Thing is an uplifting, melodic and motivational track featuring synths, piano, guitar, double bass, violins, drums and light vocals. Atmospheric and reflective, yet incredibly inspiring, It expresses positivity, strong emotional connection and success. Upbeat and positive, it is suitable for your business/corporate projects, videos, websites, films, creative pursuits and more.

Autonomy full length ambient electronic

A full length composition that is ambient electronic in style and features analogue and software synths with electronic drums. A gentle sound-bed that would suit contemplative design projects.

Tracking-as-recognition for articulated full-body human motion analysis

This paper addresses the problem of markerless tracking of a human in full 3D with a high-dimensional (29D) body model Most work in this area has been focused on achieving accurate tracking in order to replace marker-based motion capture, but do so at the cost of relying on relatively clean observing conditions. This paper takes a different perspective, proposing a body-tracking model that is explicitly designed to handle real-world conditions such as occlusions by scene objects, failure recovery, long-term tracking, auto-initialisation, generalisation to different people and integration with action recognition. To achieve these goals, an action's motions are modelled with a variant of the hierarchical hidden Markov model The model is quantitatively evaluated with several tests, including comparison to the annealed particle filter, tracking different people and tracking with a reduced resolution and frame rate.

Physiological responses of elite junior Australian Rules footballers during match-play

Australian Football (AF) is Australia's major football code. Despite research in other football codes, to date, no data has been published on the physiological responses of AF players during match play. Fifteen athletes (17.28 ± 0.76 yrs) participated in four pre-season matches, sanctioned by Australian Football League (AFL) Victoria, investigating Heart Rate (HR), Blood Lactate (BLa), Core Temperature (Tcore), and Hydration status. Match HR was measured continuously using HR monitors. BLa was measured via finger prick lancet at the end of each quarter of play. Tcore was measured by use of ingestible temperature sensor and measured wirelessly at the end of each quarter of play. Hydration status was measured using refractometry, measuring urine specific gravity, and body weight pre and post-match. Environmental conditions were measured continuously during matches. Results of HR responses showed a high exertion of players in the 85-95% maximum HR range. Elevated mean BLa levels, compared to rest, were observed in all players over the duration of the matches (p = 0.007). Mean Tcore rose 0.68 °C between start and end of matches. Mean USG increased between 0.008 g/ml (p = 0.001) with mean body weight decreasing 1.88 kg (p = 0.001). This study illustrates physiological responses in junior AF players playing in the heat as well as providing physiological data for consideration by AF coaching staff when developing specific training programs. Continued research should consider physiological measurements under varying environments, and at all playing levels of AF, to ascertain full physiological responses during AF matches.