Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 20 )

2019 ( 229 )

2018 ( 278 )

2017 ( 279 )

Custom range...

Search Results: 1 - 10 of 219604 matches for " C Myburgh "
All listed articles are free for downloading (OA Articles)
Page 1 /219604
Display every page Item
Mountain bike racing - the influence of prior glycogen-inducing exercise and glutamine supplementation on selected stress and immune parameters
C Smith, KH Myburgh
South African Journal of Sports Medicine , 2006,
Abstract: Objective. To investigate the effect of pre-exercise glutamine supplementation and the influence of a prior acute bout of glycogen-reducing exercise on the general stress and immune response to acute high-intensity cycling. Design. Randomised, double-blind, cross-over supplementation study. Setting and intervention. Subjects performed a series of 4 simulated mountain-bike races lasting ≈60 minutes each on separate days 1 week apart, with/ without prior glycogen- reducing exercise on a known outdoor course with/ without pre-exercise glutamine supplementation. Blood samples were collected pre- and immediately post-exercise after each race. Main outcome measures. Circulating concentrations of cortisol (COR) and dehydroepiandrosterone-sulphate (DHEAS) were assessed at all time points, as well as changes in white blood cell (WBC) subpopulation distribution. Results. COR was elevated in all groups post-exercise (p < 0.0001), but neither glycogen reduction, nor glutamine supplementation had any effect. DHEAs increased post-exercise (p < 0.05), with a greater relative increase in glutamine-supplemented subjects (p = 0.07). Total WBC and neutrophil counts in all groups were elevated after exercise (both p < 0.0005). Glutamine supplementation had no effect on differential WBC counts or distribution, but total WBC (p = 0.06) and monocyte (p < 0.05) counts showed greater increases after glycogen reduction. Gluta- mine supplementation was associated with greater postexercise decreases in CD4+ count (p = 0.07) and CD4+: CD8+ ratio (p = 0.01) after glycogen-reducing exercise. Conclusions. We conclude that pre-exercise glutamine supplementation may have an anticortisol effect by enhancing the DHEAS response to exercise stress. The suppressive effect of glutamine supplementation on CD4+: CD8+ ratio and its positive effect on monocyte count after repeated bouts of exercise warrants further investigation. South African Journal of Sports Medicine Vol. 18 (4) 2006: pp. 122-128
Meta-synthesis on learners’ experience of aggression in secondary schools in South Africa
C Myburgh, M Poggenpoel
South African Journal of Education , 2009,
Abstract: This meta-synthesis is on research conducted by different researchers in a team research project on learners’ experience of aggression in secondary schools in South Africa. The objective was to obtain a broader understanding of their experience of aggression in different contexts in South Africa, as well as possible ways to assist learners to address the experienced aggression. Eleven completed research projects were purposively sampled. Data were collected utilising the following headings: objectives, sampling, research design, research method, and research results, and guidelines. At the end of the meta- synthesis process the results are described, with supporting direct quotations from participants and a literature control. Guidelines for learners to cope with aggression are described.
A Low Complexity Hopfield Neural Network Turbo Equalizer
Herman C Myburgh and Jan C Olivier
EURASIP Journal on Advances in Signal Processing , 2013, DOI: 10.1186/1687-6180-2013-15
Abstract: In this paper it is proposed that a Hopfield Neural Network (HNN) can be used to jointly equalize and decode information transmitted over a highly dispersive Rayleigh fading multipath channel. It is shown that a HNN MLSE equalizer and a HNN MLSE decoder can be merged in order to realize a low complexity joint equalizer and decoder, or turbo equalizer, without additional computational complexity due to the decoder. The computational complexity of the Hopfield Neural Network Turbo Equalizer (HNN-TE) is almost quadratic in the coded data block length and approximately independent of the channel memory length, which makes it an attractive choice for systems with extremely long memory. Results show that the performance of the proposed HNN-TE closely matches that of a conventional turbo equalizer in systems with short channel memory, and achieves near-matched filter performance in systems with extremely large memory.
Academic achievement and time concept of the learner
R C Grobler,C PH Myburgh
Health SA Gesondheid , 2001, DOI: 10.4102/hsag.v6i1.60
Abstract: The time concept and academic achievement of a group of high school learners were investigated and the results are described in this article. Opsomming Die tydkonsep en akademiese prestasie van ‘n groep ho rskool leerders is ondersoek en die resultate is beskryf in hierdie artikel. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Low Complexity MLSE Equalization in Highly Dispersive Rayleigh Fading Channels
H. C. Myburgh,J. C. Olivier
EURASIP Journal on Advances in Signal Processing , 2010, DOI: 10.1155/2010/874874
Abstract: A soft output low complexity maximum likelihood sequence estimation (MLSE) equalizer is proposed to equalize M-QAM signals in systems with extremely long memory. The computational complexity of the proposed equalizer is quadratic in the data block length and approximately independent of the channel memory length, due to high parallelism of its underlying Hopfield neural network structure. The superior complexity of the proposed equalizer allows it to equalize signals with hundreds of memory elements at a fraction of the computational cost of conventional optimal equalizer, which has complexity linear in the data block length but exponential in die channel memory length. The proposed equalizer is evaluated in extremely long sparse and dense Rayleigh fading channels for uncoded BPSK and 16-QAM-modulated systems and remarkable performance gains are achieved.
The lived experiences of late-adolescent female suicide survivors: ‘A part of me died’
WA Hoffmann, C Myburgh, M Poggenpoel
Health SA Gesondheid , 2010,
Abstract: People’s thoughts often focus on the suicide victim immediately after a completed suicide. Yet, the real victims of such an event are those individuals who are left behind to cope with the aftermath of the suicide. This phenomenological psychological study explored the lived experiences of lateadolescent suicide survivors, particularly those negative experiences that seemed to worsen in the weeks and months after a significant other’s completed suicide. The research participants were five female late-adolescents (aged 17–22 years) who were recruited by means of purposive sampling at a South African tertiary institution and at youth camps. Data collection consisted of collagefacilitated, face-to-face phenomenological interviews. In addition, some participants provided documentary material in the form of personal diaries, letters and poems. The data analysis was conducted according to Giorgi’s phenomenological method. The following salient experiences emerged during the data analysis: guilt, self-blame, blaming others or God, anger, loss or restriction of ‘self’, depression, suboptimal behavioural coping patterns, changes in relationship dynamics, and suicidality. The results of this study can be used by mental health professionals and caregivers to support adolescent suicide survivors effectively, in the midst of their mourning.
The effect of a professional cricket match schedule on selected immune parameters
AW Williams, KH Myburgh, C Smith
South African Journal of Sports Medicine , 2004,
Abstract: Objective. The impact of a professional cricket match schedule on white blood cell (WBC) distribution and lymphocyte activation (CD69 expression) was investigated. Methods. After a 3-month pre-season training period, physical and immune parameters were determined in 14 male cricketers before (B) and after (A) an intensive 5- week match schedule. Results. Exercise test results were unchanged from B to A. Total WBC counts were similar, but total lymphocyte and lymphocyte subpopulation counts decreased significantly. The CD4:CD8 ratio did not change. After in vitro stimulation, percentage CD4+CD69+ cells increased (B: 54.4 ± 9.7%, A: 64.0 ± 8.5%, p < 0.01), but absolute CD4+CD69+ cell counts did not change from B to A. In contrast, both the %CD8+CD69+ cells and absolute CD8+CD69+ cell count remained similar. Conclusion. A strenuous, interregional, professional cricket match schedule resulted in a decreased number of lymphocytes, but relatively increased in vitro reactivity of CD4+ cells, thus maintaining the absolute capacity of the CD4+ cells to become activated on stimulation. In cricketers who suffered upper respiratory tract symptoms during the match schedule (N = 7), none of the immune parameters investigated differed significantly from the others at B or A. SA Sports Medicine Vol.16(2) 2004: 22-27
The relationship between the perception of own locus of control and aggression of adolescent boys
L Breet, C Myburgh, M Poggenpoel
South African Journal of Education , 2010,
Abstract: Aggression is increasingly seen in most parts of South African society. Aggressive behaviour of boys in secondary school often results from frustrations caused by perceived high expectations of others regarding the role, locus of control, and personality of boys. Locus of control plays an important role in a person’s perception concerning a situation and possible reactions to what is happening, or should be happening. A 56-item questionnaire, based on Rotter’s “Locus of control” questionnaire, and the DIAS Scale were used. The questionnaire was completed by 440 boys in Grades 9, 10, and 11. Various factor, item and differential statistical analyses were conducted. Three constructs were identified, i.e. physical, verbal, and indirect aggression. Results indicated that locus of control has a significant influence on verbal and indirect aggression. The differential analysis indicated that contextual variables (language of tuition, age, and grade) play a significant, but not substantial, role in aggression. Furthermore, boys with an internal locus of control are significantly and substantially less aggressive than boys with an external locus of control, with respect to physical, verbal and indirect aggression.
Multivariate differential analyses of adolescents’ experiences of aggression in families
C Myburgh, M Poggenpoel, D Du Plessis
South African Journal of Education , 2011,
Abstract: Aggression is part of South African society and has implications for the mental health of persons living in South Africa. If parents are aggressive adolescents are also likely to be aggressive and that will impact negatively on their mental health. In this article the nature and extent of adolescents’ experiences of aggression and aggressive behaviour in the family are investigated. A deductive explorative quantitative approach was followed. Aggression is reasoned to be dependent on aspects such as self-concept, moral reasoning, communication, frustration tolerance and family relationships. To analyse the data from questionnaires of 101 families (95 adolescents, 95 mothers and 91 fathers) Cronbach Alpha, various consecutive first and second order factor analyses, correlations, multiple regression, MANOVA, ANOVA and Scheffè/ Dunnett tests were used. It was found that aggression correlated negatively with the independent variables; and the correlations between adolescents and their parents were significant. Regression analyses indicated that different predictors predicted aggression. Furthermore, differences between adolescents and their parents indicated that the experienced levels of aggression between adolescents and their parents were small. Implications for education are given.
The effect of pyridoxal-5-phosphate on serum alanine aminotransferase activity in dogs suffering from canine babesiosis
E.C. Myburgh,A. Goddard
Onderstepoort Journal of Veterinary Research , 2010, DOI: 10.4102/ojvr.v76i3.38
Abstract: Accurate measurements of serum aminotransferase (ALT) activity in dogs relies on the endogenous pro-enzyme pyridoxal 5-phosphate (P5P). The purpose of this study was to determine whether the exclusion of P5P from the analytical method causes an underestimation of serum ALT activity in dogs suffering from babesiosis and in those manifesting evidence of hepatocellular damage, and to determine if anorexia causes sufficient P5P depletion to affect in vitro serum ALT activity. One-hundred-and-twenty healthy control dogs and 105 Babesia-infected dogs were included in the study. Two methods for ALT measurement were used: Method 1 included P5P, and Method 2 excluded P5P from the reaction mixture. Higher serum ALT activity was measured with Method 1 in the Babesia-infected dogs (P < 0.001), as well as in 14 dogs with suspected hepatocellular damage (P = 0.03). Duration of anorexia had no effect, irrespective of the method used. Although inclusion of P5P to the reaction mixture consistently resulted in higher measured serum ALT activity, the differences were too small to have led to incorrect diagnoses in the Babesia-infected dogs suspected of liver disease.
Page 1 /219604
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.