The purpose of this study was to determine the effects of evaluation apprehension and achievement on subjects' internal causal attributions in a physical skills task. One hundred and twenty private school male students, aged 12 to 19, were assigned to one of two conditions of evaluation. Feedback on level of achievement was given upon completion of the task and the students asked to complete a seven item attribution questionnaire. A 2 x 2 (evaluation x achievement) multivariate analysis of variance was used to examine differences across conditions among the four internal attributions. The results indicated that the subjects' attributions were affected by evaluation, as well as different levels of achievement. The predicted interactive effect of evaluation and achievement on attribution was not found. It was concluded that there was a flaw in the logic which suggested that internal attributions would be affected by an interaction of evaluation apprehension and achievement.

No description available.

Background. In children with autism spectrum disorders (ASD), sensori-motor development and functional skills in activities of daily living (ADL) remain little explored in comparison to the other domains of development. Objectives. To determine the impact of sensori-motor skills on functional skills in ADL of preschool children with ASD, and to examine their type of sensory responses, their motor skills and their functional skills in ADL. Methods. This project is a pilot and cross-sectional study. Thirty-five children with ASD, three to four years of age, have been recruited and assessed. Control groups are also included: eight children with developmental delay (DD) and five children with typical development (TD). A battery of diagnostic and clinical tests was used. Results. ASD and DD groups have significantly more atypical sensory responses than the TD group as measured by the Sensory Profile. The ASD group has significantly poorer motor skills than controls (TD and DD) based on the Peabody Developmental Motor Scales --2nd edition (PDMS-2). Self-care skills of the ASD group fall below 2 standard deviations (SD) on the Functional Independence Measure for Children (WeeFIM). Daily living skills (DLS) of the ASD group are significantly poorer than controls on the Vineland Adaptive Behavior Scales -- Second Edition (VABS-II). The largest percentage of variability in self-care skills, as measured by the WeeFIM, is explained by cognitive functioning and auditory processing, while personal skills, as measured by the VABS-II, are predicted by fine motor skills and sensory avoiding. Conclusion. Pre-school children with ASD, but also children with DD, react differently to sensory stimuli than typically developing children. Also, children with ASD have significantly poorer motor skills than DD and TD children. These sensory and motor difficulties affect the functional skills in ADL. Therefore, it will be important clinically to individually assess and consider sensori-motor and functional skills in ADL of children with ASD. Future interventions may then aim at improving and supporting the development and autonomy of these children. In turn this may assist caregivers by reducing their care load. / Keywords: autism spectrum disorders, sensory responses, motor skills, functional skills, activities of daily living

The learning and retention adaptations of muscle activity were studied during a novel multi-joint task. Electromyographic (EMG) signals were recorded from the posterior deltoid, long and lateral heads of the triceps, pectoralis major, biceps and brachioradialis muscles. These data were assayed in a pattern recognition analysis (SVD) to ascertain the minimum number of 'common features' or waveforms (W's) required to describe the set of input EMG patterns (IP). / Fifteen participants performed targeted arm movements, which incorporated the shoulder and elbow articulations, as fast and as accurately as possible in the horizontal plane. Both experimental (E) and control (C) groups were employed. The E group was trained (Day 1 to Day 4) and tested both pre- and post-learning. They were further re-tested during a retention period (RET) consisting of 1, 2, 4, 6 and 8 week post-learning sessions. The C group was tested before and after learning and at the end of the RET period. (Abstract shortened by UMI.)

The present thesis investigated the process of gross motor skill acquisition in the context of how movement pattern characteristics are organized and modified as a result of learning. The process of multisegmental skill acquisition was studied using performance production measures as a window to explore stable and transient changes in the movement control process. Bernstein's principles of exploitation of motion dependent torques, and the minimization of the degree of freedom were tested. / Twenty male subjects performed a total of 240 trials, as fast and accurate as possible, over 4 sessions for two tasks with different level of complexity (10 subjects per task). Kinematic and EMG data were acquired for a two segment model of the arm using a lightweight, adjustable manipulandum, and surface EMG for the PDL, PEC, TRI, and BIC muscles. Movement organization characteristics were revealed by wave pattern analyses performed with a phase breakdown technique, CCCF on torque partitioning components, and the CFs on the muscle activation waveforms. / The experimental protocol allowed enough practice for the tasks to be learned resulting in PT decrease. Consistent adaptations in movement organization were revealed by all three levels of analysis. Improvement in the performance production measures were in the same direction for both learning conditions, and the rate of change within experimental sessions decreased over time. The significant adaptations in movement organization occurred at the critical phases of each task (i.e. the power absorption--phase simple task, and the reversal phase--complex task). The EMG and joint torque components demonstrated significant amplitude and profile changes particularly during the critical phases. The subjects learned to perform the tasks faster by compensating the motion dependent torques components with the muscle torques in time and amplitude. This finding was consistent with the principle of exploitation of motion dependent torques which was enhanced with learning. Significant task specific motor program adaptations were revealed by the SVD analysis. The minimization of the degree of freedom hypothesis is consistent with the increasing covariation observed over learning between the antagonists PEC and BIC in the simple task, and for both the agonists PDL and TRI and antagonists PEC and BIC in the complex task. In addition the results justified the use of waveform analysis on performance production measures, as a method that can reveal important adaptation details in the underlying control mechanisms for gross motor skill.

No description available.

The ease with which our brains learn to control our bodies belies intricate neural processing which remains poorly understood. We know that a network of brain regions work together in a carefully coordinated fashion to allow us to move from one place to another. In mammals, we know that the motor cortex plays a central role in this process, but precisely how its activity contributes to control is a matter of long and continued debate. In this thesis we demonstrate the need for developing mechanistic neural network models to address this question. Using such models, we show that contentious response properties of non-human primate primary motor cortex (M1) neurons can be understood as reflecting control processes which take into account the physics of the body. And we develop new computational techniques for teaching neural network models how to execute control. In the first study (Chapter 2), we critically examined a recently developed correlation-based descriptive model for characterizing the activity of M1 neuron activity. In the second study (Chapter 3), we developed neural network control laws which performed reaching and postural tasks using a physics model of the upper limb. We show that the population of artificial neurons in these networks exhibit preferences for certain directions of movement and certain forces applied during posture. These patterns parallel empirical observations in M1, and the model shows that the patterns reflect particular features of the biomechanics of the arm. The final study (Chapter 4) develops new techniques for building network models. To understand how the brain solves difficult control tasks we need to be able to construct mechanistic models which can do the same. And, we need to be able to construct controllers that compute via simple neuron-like units. In this study, we combine tools for automatic computation of derivatives with recently developed ideas about second-order approaches to optimization to build better neural network control laws. Taken together, this thesis helps develop arguments for, and the tools to build mechanistic neural network models to understand how motor cortex contributes to control of the body. / Thesis (Ph.D, Neuroscience) -- Queen's University, 2014-01-31 10:34:43.816

Theoretical mechanical benefits of biarticular muscles include reduced displacements and force potentiating shifts in linear velocities during multi-joint coupled motions. A cadaveric model was developed to compute muscle kinematics of biceps femoris (BFL and BFS) during four classes of coupled knee and hip joint motion, as well as running and walking gait (Six subjects, Vicon Motion Analysis). The examples of the classes of motion were: KEHE-jump (knee extension and hip extension), KFHF-tuck (knee flexion and hip flexion), KFHE-kick (knee flexion and hip extension), and KEHF-paw (knee extension and hip flexion). BFL peak and mean velocity shifts relative to BFS were seen in all four coupling classes (p<0.05) and the majority of the gait subclasses (p<0.05). Muscle displacements were larger in BFL for both KFHE-paw and KEHF-kick (p<0.05), smaller in KFHF-tuck (p<0.05), but not significantly different in KEHE-jump or during most of the running gait subclasses, except for during KFHE-late mid stance and KEHF-mid swing, where they were larger for BFL (p<0.05). The mechanical benefits associated with BFL velocity shift relative to BFs were identified in KFHF, KEHF motions, and certain subclasses of gait. In contrast, there were potential mechanical detriments due to velocity shift relative to BFs in the KEHE-jump, KFHE-paw, and the majority of KEHE and KFHE subclasses in both gait cycles. The possible mechanical benefits associated with displacement conservation of BFL relative to BFs would be realized in KFHF-tuck jump, but not during KEHE-jump and the gait cycle subclasses. The findings of this study reveal both mechanical benefits and detriments of biarticular muscles, and have immediate implications for neural control of biarticular muscles during movement.

Hawk Turbine AB tillverkar mindre jetmotorer som ofta används i små obemannade och radiostyrda flygplan. I flygplansmodellen Lockheed T-33 Shooting Star är motorn monterad inuti planet varför luften måste ledas ut till atmosfären. För bästa möjliga prestanda måste ejektorn och utblåsröret som leder luften dimensioneras efter motor och flyghastighet. En 3-dimensionell CAD modell av flygplanets installation skapades och därefter simulerats i en virtuell vindtunnel med hjälp av datorprogrammet SolidWorks Flow Simulation. Flera olika utblåsrör i varierande storlekar samt olika former har testats för att avgöra om ändringar kan förbättra prestandan ytterligare. Simulationsresultat visar att det går att förbättra nuvarande konfiguration med 5,99 % om diametern på utblåsröret minskas från 75 mm till 70 mm med en bibehållen form på utblåsröret. / Hawk Turbine AB is a company that manufactures small jet engines which are often used in smaller unmanned and radio-controlled aircrafts. In the Lockheed T-33 Shooting Star aircraft the engine is mounted in the center of the aircraft and therefore requires ducts to be used for directing the exhaust to the atmosphere. For optimum performance the ejector and the exhaust manifold must be designed for the engine and the flight velocity. A 3-dimentional CAD model of the aircrafts ducts was created. The model was then used in virtual wind tunnel testing using the software SolidWorks Flow Simulation. Different shapes and sizes of the manifolds were tested in the simulations to determine if modifications can further improve the performance. The simulations show that the performance of the current manifold can be improved by 5,99 % if the diameter of the manifold is reduced from 75 mm to 70 mm while keeping the shape of the manifold unaltered.

No description available.