• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 732
  • 182
  • 127
  • 127
  • 127
  • 127
  • 127
  • 126
  • 32
  • 24
  • 15
  • 8
  • 8
  • 3
  • 2
  • Tagged with
  • 1539
  • 1539
  • 547
  • 232
  • 170
  • 158
  • 137
  • 135
  • 134
  • 116
  • 114
  • 102
  • 90
  • 89
  • 88
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1191

The Physiological Control of Verbal Behavior

Field, Douglas Preston 08 1900 (has links)
The current study sought to investigate whether physiological responses, such as the electrodermographic response (EDG) and/or the frontalis muscle electrical potential (EMG) could be developed as a source of control over verbal responses. Discrimination training procedures using points exchangeable for money were employed to condition verbal responses occasioned by minute interoceptive events with 2 adult human subjects. Specific verbal responses were reinforced in the presence of changes in EDG with Sl and EDG and EMG with S2. Stimulus control over differentiated verbal responses was demonstrated with both subjects. The results suggest that minute interoceptive events can enter into controlling relations with verbal responses and that this control is partially a function of the size or range of physiological responses as well as conditioning history.
1192

Perceived constraints to physical activity among paramedical institution students in Uganda

Nizeyimana, Eugene January 2005 (has links)
Magister Scientiae (Physiotherapy) - MSc(Physio) / Research has clearly shown that all individuals will benefit from regular physical activity. Unfortunately, young adults including college and university students are not physically active on a regular basis worldwide. In the developing world particularly in Sub- Saharan Africa, physical inactivity along with tobacco use, poor diet and nutrition are increasingly parts of today’s lifestyle. Physical activity declines with age and the most important decline appear to be during the transition period from high school to university and during university years. The aim of this study was to assess the level of physical activity, to investigate the perceived constraints to physical activity and to determine whether socio-demographic characteristic have an influence on participation in physical activity and perceived constraints to physical activity among paramedical institutions students in Uganda. A cross-sectional study with descriptive quantitative design was conducted. Four hundred (400) paramedical institution students were selected using a stratified random sampling technique. A self-administered questionnaire adopted from the literature was used to collect the data. A response rate of 90% was obtained. Descriptive and inferential statistics using the statistical package for social sciences were used to analyze the data. The relationships and associations between different variables were determined by carrying out significant tests using chi-square tests. Alpha level was set at 0.05. The mean age of the sample was 22.44 years (SD = 2.03). Males constituted 73.9% and females constituted 26.1% of the sample. Students from eight (8) health professional courses participated in the study. Over half (59%) of participants were classified as physically active and 41% were classified as inactive or sedentary. For male participants, lack of the right equipment to exercise and wanting to do other things in their free time were perceived as the major constraints to physical activity. For female participants, lack of motivation and tiredness after exercise were perceived as the major constraints to physical activity. The findings of this study demonstrate that there is an influence of socio-demographic characteristics such as gender, year of the study and different departments/schools on participation in physical activity and perceived constraints to physical activity. They also indicate the need of health promotion intervention aiming at promoting physical activity among paramedical institution students in Uganda. / South Africa
1193

Perceptions of constraints to recreational sports participation :a case study of the University of the Western Cape (UWC) undergraduate female students

Solomon, Ghebremedhin Asihel January 2005 (has links)
Magister Artium (Sport, Recreation and Exercise Science) - MA(SRES) / The effects of attitudes and perceived constraints on behavior and the choices females make about involvement in recreational sports, exercise, and other physical recreation activities are important to consider if females physical, social, and emotional quality of life is to be enhanced. The main aim of this study was to explore the perception held by female undergraduate students at UWC regarding the physical and socio-cultural constraints that influence their participation in recreation sport. / South Africa
1194

Cardiovascular effects of Leonotis leonurus extracts in normotensive rats and in isolated perfused rat heart

Obikeze, Kenechukwu January 2004 (has links)
Magister Pharmaceuticae - MPharm / This thesis discussed the cardiovascular effects of the aqueous leaf extract and a fraction of the methanol extract of Leonotis leonurus, a plant commonly used in traditional medicine in South Africa for the treatment of hypertension and other cardiac problems. The cardiovascular effects was tested on anaesthetized normotensive male Wistar rats and isolated perfused rat hearts. / South Africa
1195

Investigating the challenges facing Itinerant Learning Support Educators (ilse) in the context of inclusive education in the Metro South Education District

Arendse, Agnetha January 2010 (has links)
Magister Educationis - MEd / The study aims to understand the challenges facing the Itinerant Learning Support Educators in an Inclusive Education framework. At the onset of the study there were very limited research studies and literature available on the challenges facing Itinerant Learning Support Educators hence literature in the study drew on the development and history of Special Education towards a global shift with regard to Inclusive Education policy development. As such the literature was utilized to understand how global phenomena and policies in developed countries impact on local policy transformation and contexts. The study followed a qualitative research approach to explore the challenges facing Itinerant Learning Support Educators in performing their functions. To gain an in depth understanding of their perceptions a case study method was followed and data collection techniques included focus group interviews. The sample in this study comprised of 14 Itinerant Learning Support Educators. The data was analyzed using a thematic approach. The findings of this study highlighted that despite a shift towards Inclusive Education in South Africa, Itinerant Learning Support Educators found themselves challenged by a range of contextual issues that impacted on the effective delivery of inclusive principles and practices. The study recommends that the Department of Education should take cognisance of these challenges, review the job description of Itinerant Learning Support Educators and put clear guidelines and support structures in place to support them in functioning optimally within an Inclusive Education paradigm. / South Africa
1196

An Investigation of Selected Female Singing- and Speaking-Voice Characteristics Through Comparison of a Group of Pre-Menarcheal Girls to a Group of Post-Menarcheal Girls

Williams, Bonnie Blu 05 1900 (has links)
The purpose of this study was to compare the speaking fundamental frequency, physiological vocal range, singing voice quality, and self-perceptions of the singing and speaking voice between two groups of girls ages 11 through 15 years, who were pre-menarcheal by 6 months and post-menarcheal by 10 months or more. Subjects were volunteers who attended a North Texas public school system. Each subject was examined by an otolaryngologist. Age, height, weight, a hearing screening, and information on music classes and/or private music lessons were obtained. The speaking fundamental frequency measure was obtained by having each subject speak for 30 seconds on a subject of choice and read a passage of approximately 100 syllables. The vocal range measure was obtained by having each subject begin at an arbitrary pitch and sing mah and moo up the scale as high as possible and mah and moo down the scale as low as possible. These four measures were repeated with the researcher giving visual gestures. For singing-voice quality, each subject sang "America" in the key of her choice and again in the key of F major. Each subjects singing voice was rated according to breathiness. Data regarding self-perceptions of the singing and speaking voice were obtained through a rating assessment of 10 questions and a conversation with each subject. There were no significant differences between the means of the pre-meanarcheal and post-menarcheal girls on speaking fundamental frequency, physiological vocal range, and singing-voice quality. But, more of the post-menarcheal girls exhibited lower speaking pitches, lower singing ranges, and increased breathiness in their singing voices than did the pre-menarcheal girls. Two questions of the perceptions rating assessment were significant, with the post-menarcheal girls citing higher incidences of vocal inconsistencies than the pre-menarcheal girls. The findings of the qualitative data analysis indicated that more post-menarcheal girls had an adequate vocabulary to describe various aspects of their singing and speaking voices than did the pre-menarcheal girls.
1197

An Investigation of the Whistle Register in the Female Voice

Walker, Steven 05 1900 (has links)
The purpose of the study was concerned with specific elements of the portion of the female voice commonly referred to as whistle or flute register. Three elements of vocal production were chosen for which past research has demonstrated relationships to source function. These elements included spectral characteristics, airflow rates, and perceptual identification. The research compared what the singer-subjects perceived as being whistle register phonations with that which they perceived as being head register phonations. A comparative technique was utilized where pitch, intensity and phonemic category were held relatively constant, register, therefore, being the only variable. Spectral characteristics and airflow rates of the two subject-determined registers were compared. In addition, an attempt was made to determine if the whistle register could be perceptually differentiated on the basis of voice quality,
1198

Traumeel S : the sportsman's answer to enhanched exercise performance and the overtraining syndrome?

Jordaan, Dirk Pieter 20 April 2007 (has links)
Research indicates that eccentric exercise is associated with delayed onset of muscle soreness (DOMS). The symptoms associated with DOMS is similar to other inflammatory conditions e.g. pain, swelling and tissue damage. The DOMS as a reaction to the muscle damage is accompanied by changes in cytokines, leukocytes and other markers of inflammation. Prolonged exercise training without adequate rest and nutrition can lead to chronic inflammation and altered cytokine production patterns, which could result in overtraining. Methodology The study included actively participating marathon runners and consisted of two groups, a control group (n = 24 athletes) and an experimental group taking Traumeel S (n = 26 athletes), assigned in a double-blind fashion. Subjects made use of the treatment protocol for a period of seven days and followed their normal training program with no additional training. DOMS was induced on day eight when subjects ran downhill at 75% of peak treadmill running speed (PTRS) for 45 minutes at a gradient of –10% with ratings of perceived exertion (RPE), perceived pain (RPP) and heart rate was measured during the run. After the DOMS was induced subjects reported for blood samples for serum creatine kinase (CK), serum cortisol and a differential white blood cell count was taken at the same time for four days after DOMS was induced. Results The t-test for independent groups was used to determine the statistical differences between the two groups and for inter-group analysis. The results showed minor and predominantly insignificant changes in CK-, basophil-, eosinophil- and lymphocyte-counts. The cortisol levels in the treated group were higher compared to the placebo group at 48-, 72- and 96-hours post-exercise. The treated subjects’ mean monocyte count fell significantly on the first day of recovery and remained significantly lower for the four days post-exercise. Conclusions The increased cortisol concentrations can assist the immune system to shut of the acute inflammatory reaction associated with DOMS and in so doing reduce exercise induced muscle damage and inflammation. The decreased monocyte counts will reduce blood vessel permeability and swelling, fewer pain receptors will be stimulated because of lower PGE2 levels associated with decreased monocyte activation. Secondary, muscle damage that can amongst others be associated with increased monocytic activity, will be limited. Additional blood tests and performance testing are needed to confirm and substantiate the findings of the research. / Dissertation (MA (Human Movement Sciences)--University of Pretoria, 2007. / Biokinetics, Sport and Leisure Sciences / unrestricted
1199

Apneic Bradycardia : terrestrial and aquatic responses in man under working conditions

Manley, Elizabeth January 1989 (has links)
The focus of this research was the reappraisal in physiological and psychophysical terms of current equivocal theories regarding the onset, course and termination of apneic bradycardia. Sixteen healthy male subjects participated in four separate testing sessions . Maximal oxygen consumption (VO₂ max) was measured on land and underwater using an identical direct, continuous progressive cycle ergometer test. On each of two other occasions subjects exercised in either environment at 50, 70 and 90% of the appropriate VO₂ max, during which time heart rate was continuously recorded. An initial apneic bout at each exercise intensity was followed by performance of the same workload without apnea for an equivalent period of time. Ratings of perceived exertion (RPE) were also monitored. While apneic bradycardia occurred at each exercise intensity studied underwater, it was apparent only at 50% VO₂ max on land. With the exception of between 50 and 90% VO₂ max on land, the mean apneic heart rates did not differ with varying exercise intensity (p<0.05); nor did the lowest heart rate recorded, although this was lower underwater than on land. Apart from 70% VO₂ max on land, apneic heart rates were lower than the equivalent values measured during exercise without apnea. Land and underwater heart rates during apneic and non-apneic conditions did not differ until 90% VO₂ max. The effects of increasing exercise intensity upon the onset of bradycardia were evident in that it occurred earlier at 50% VO₂ max underwater than at the heavier workloads, and only at 50% VO₂ max on land. The mean breath-hold duration did not differ between the land and underwater environments, nor was it affected by increasing exercise intensity. The order in which breath-holds was performed did not alter the length of apnea. Land and underwater RPE did not differ and increased with increasing exercise intensity in both environments. During apneic exercise RPE was greater than the equivalent exercise without apnea. Twelve of the original 16 subjects were divided equally into two groups on the basis of vital capacity expressed relative to body surface area. Vital capacity was measured during the first laboratory session. Neither the mean heart rate response to apneic exercise at 50% V0₂ max in both environments, nor the lowest heart rates recorded differed between groups, prompting the conclusion that lung volume did not affect apneic bradycardia. Despite a longer breath-hold duration for Group A (large relative lung volume) than Group B (small relative lung volume), the onset point of bradycardia was the same for either group when expressed relative to total breath-hold duration
1200

An investigation into control mechanisms of driving performance : resource depletion and effort-regulation

Louw, Tyron Linton January 2013 (has links)
Driver fatigue is a complex phenomenon that has a range of causal factors including sleeprelated and task-related factors. These manifest as different safety and performance outcomes. Extensive research has been applied to linking these factors to performance impairment. However, little research focuses on the mechanisms by which this link exists. This research project therefore focuses on the processes underlying how driving performance is controlled and maintained during the development on non-sleep-related driver fatigue. The main aim was to establish whether progressive impairment of driving control over a prolonged drive could be attributed to a depletion of attentional resources, as proposed by Resource Theory, or to a withdrawal of effort, as proposed by Effort-Regulation Theory. As a multicomponent skill, driving requires perception, cognition and motor output. The secondary aim of this research was therefore to assess whether a prolonged drive impairs stage-specific information processing. Participants (n=24) in three experimental groups performed a 90-minute simulated drive wherein they were expected to keep the bonnet of a car on a lane (tracking task). The three groups differed in terms of lane width: small, medium and large, corresponding to low, medium, and high task-demand, respectively. To assess the impacts of this task on stagespecific information processing, participants performed a set of resource specific tests before and after the prolonged drive. Each task had two difficulty variations to ensure that performance decrement was due not only to the task-characteristic, but specifically to resource depletion. The tests probing information processing were: a modified Fitts' tapping task for motor programming, a digit recall task for perception, and an object recognition reading task for cognition. Performance was measured as lateral deviation of the car. Physiological measures included heart rate frequency (HR) and various time- and frequencydomain heart rate variability (HRV) parameters, eye blink frequency and duration. The Borg CR-10 scale was used to evaluate subjective effort and fatigue during the task. Driving control declined over time and was supplemented by HR, HRV, blink frequency and duration, indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Driving control declined to a greater extent in the large road width group and reflected a lower parasympathetic activity, whereas the inverse was observed for the small road width group. Resource tests reveal a non-specific impairment of information processing following the prolonged drive. However, this was accompanied by an increase in parasympathetic activity. Overall, results indicate that Effort-Regulation Theory better accounts for the impairment of driving control in prolonged driving than does Resource Theory. This suggests that the impact of fatigue is guided more by task goals and intrinsic motivation than by the manner in which the fatigue state developed. Moreover, performance impairment by effort-regulation is dependant more on time on task than on task-demand

Page generated in 0.0595 seconds