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  • 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.
21

Untersuchung der Effekte einer EPO-Therapie auf die kortikale Atrophie bei chronisch-schizophrenen Patienten - eine MRT-volumetrische Studie / Evaluation of cortical effects under EPO-therapy within chronic schizophrenia - a MRT-based study

Maak, Oliver 17 July 2012 (has links)
No description available.
22

Value-based management : an assessment of the application in a mining company / Adrian Pienaar

Pienaar, Adrian Cecil Semino January 2008 (has links)
If a programme which intends to measure performance is to work successfully in an organisation, it is necessary to understand the contingent factors that need to be in place regardless of philosophical beliefs. It must be integrated with the overall strategy of the business; all approaches to performance measurement emphasise the alignment of objectives, measures, strategic decision making and rewards. This is crucial, as it is not possible to measure performance unless it is clear what an organisation is trying to achieve. Value-based management (VBM) is a powerful management framework with the aim to focus all managerial processes on shareholder wealth creation. It therefore encourages all staff levels within the organisation to focus on value creation. Various metrics have been developed to measure the value creation process within the organisation. The application of VBM principles at the lower levels within the organisation is critical to ensure that lower level staff applies value-creating principles in their daily jobs. Anglo Platinum has also adopted VBM, which will help the organisation to enhance decision-making and ensure pursuing strategies that maximise value. Anglo VBM is a management system which will enable the company to significantly improve the quality and speed of decision-making and to drive performance and profitable growth. It requires a detailed understanding of where and why value is created or consumed within the businesses through assembling a comprehensive fact base. A quantitative study was done to collect primary data through the use of standardised questionnaires that were distributed to respondents at Bleskop and Brakspruit shafts as well all the accountants at Rustenburg Platinum Mine, which forms part of Anglo Platinum. The results from this study indicate that there is a low understanding of VBM as well as a strong focus on business unit objectives and on short-term goals. A key recommendation would be to use incentive mechanisms to be aligned to VBM. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2009.
23

Neurofunctional and Neuroanatomical Hippocampal Deficits and Connectivity Differences in Schizophrenia Compared to Healthy Control Participants Tested on a Virtual Reality Navigation Wayfinding Task: An fMRI, VBM and Effective Connectivity Study

Ledoux, Andrée-Anne 24 April 2013 (has links)
Episodic memory is a key feature in learning. One must remember past events to act upon a present situation. Episodic memory has been reported to be impaired in individuals with schizophrenia. In order to have an intact episodic memory the contextual features (context) must be bound to the content of the event; this mechanism is referred to as contextual binding. It is proposed that binding errors during the encoding process are responsible for episodic memory impairments in schizophrenia. Since the hippocampal formation is considered to be the central element for contextual binding, it is hypothesized that the synaptic disorganization described in this condition results in such a deficit. Moreover, the hippocampus mediates and influences other cognitive processes such as learning and executive functioning. Hence, a contextual binding deficit can have important consequences on cognition, behaviour and emotions. The object of this dissertation was to investigate the neurofunctioning, neuroanatomy and neurofunctional connectivity of the hippocampus while performing a task that utilized contextual binding mechanisms. Since spatial relational processing is part of contextual binding and is rooted in the hippocampal regions, visuospatial navigation, more precisely a wayfinding task, was used as a probe to activate the hippocampus and its associated regions in a group of patients with schizophrenia and matched healthy controls. The following dissertation presents three original research papers contributing to our understanding of the contextual binding and hippocampal deficits in schizophrenia. The first paper investigates the neurofunctioning of the hippocampus with a wayfinding task. The second paper investigates the hippocampal structural abnormality in schizophrenia and how it relates to performance during the wayfinding task. The third paper explores effective connectivity of the hippocampus with other brain regions involved in navigation in schizophrenia with a particular interest in the prefrontal cortex. These three studies demonstrate significant neurofunctional, neuroanatomical, and neurofunctional connectivity deficits in the hippocampus of the patients with schizophrenia compared to a healthy control population. Results of all three papers are further discussed in terms of research and clinical implications.
24

Value-based management : an assessment of the application in a mining company / Adrian Pienaar

Pienaar, Adrian Cecil Semino January 2008 (has links)
If a programme which intends to measure performance is to work successfully in an organisation, it is necessary to understand the contingent factors that need to be in place regardless of philosophical beliefs. It must be integrated with the overall strategy of the business; all approaches to performance measurement emphasise the alignment of objectives, measures, strategic decision making and rewards. This is crucial, as it is not possible to measure performance unless it is clear what an organisation is trying to achieve. Value-based management (VBM) is a powerful management framework with the aim to focus all managerial processes on shareholder wealth creation. It therefore encourages all staff levels within the organisation to focus on value creation. Various metrics have been developed to measure the value creation process within the organisation. The application of VBM principles at the lower levels within the organisation is critical to ensure that lower level staff applies value-creating principles in their daily jobs. Anglo Platinum has also adopted VBM, which will help the organisation to enhance decision-making and ensure pursuing strategies that maximise value. Anglo VBM is a management system which will enable the company to significantly improve the quality and speed of decision-making and to drive performance and profitable growth. It requires a detailed understanding of where and why value is created or consumed within the businesses through assembling a comprehensive fact base. A quantitative study was done to collect primary data through the use of standardised questionnaires that were distributed to respondents at Bleskop and Brakspruit shafts as well all the accountants at Rustenburg Platinum Mine, which forms part of Anglo Platinum. The results from this study indicate that there is a low understanding of VBM as well as a strong focus on business unit objectives and on short-term goals. A key recommendation would be to use incentive mechanisms to be aligned to VBM. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2009.
25

Gêmeos monozigóticos discordantes para transtorno de identidade de gênero : um estudo da espessura cortical e de morfometria baseada em voxels através de imagens de ressonância magnética estrutural

Picon, Felipe Almeida January 2012 (has links)
O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.
26

Gêmeos monozigóticos discordantes para transtorno de identidade de gênero : um estudo da espessura cortical e de morfometria baseada em voxels através de imagens de ressonância magnética estrutural

Picon, Felipe Almeida January 2012 (has links)
O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.
27

Gêmeos monozigóticos discordantes para transtorno de identidade de gênero : um estudo da espessura cortical e de morfometria baseada em voxels através de imagens de ressonância magnética estrutural

Picon, Felipe Almeida January 2012 (has links)
O transtorno de identidade de gênero (TIG) carateriza-se pela persistente convicção de pertencer ao sexo oposto. Apesar das diferentes abordagens metodológicas e de inúmeros estudos, sua etiologia ainda permanece desconhecida. Sabe-se da influência de fatores ambientais, hormonais, genéticos e de alterações neuroanatômicas. A literatura em neuroimagem ainda é extremamente restrita, e estudos com foco em espessura cortical inexistem. Achados neuroanatômicos de morfometria baseada em voxels com maior volume de massa cinzenta já foram relatados em regiões ligadas ao circuito neural da senso-percepção. Hipotetizamos que diferenças de espessura cortical estariam localizadas nas regiões desse circuito. Estudamos um par de gêmeos monozigóticos masculinos discordantes para TIG (masculino-para-feminino) aplicando VBM e SBM (FreeSurfer). Evidenciamos maior volume de substância cinzenta e maior espessura cortical na junção tempo-parietal direita, córtex frontal inferior direito e córtex da insula direito no gêmeo TIG-MTF em relação ao seu irmão. O presente estudo agrega o achado de espessura cortical na caracterização das alterações neuroanatômicas do TIG. / Gender Identity Disorder (GID) is characterized by the persistent conviction of belonging to the opposite sex. Despite all the different technical approaches and the several studies performed, its etiology still remains unknown. There is knowledge about the influence of environmental hormonal, genetic and neuroanatomic factors involved. The literature about GID neuroimaging is extremely restrict and there are no studies focusing on cortical thickness. The neuroanatomical findings from Voxel-Based Morphometry (VBM) have reported regions within the sense-perception network with increased grey matter volume. We hypothesized that differences of cortical thickness would be found in the cortical areas of this network. Thus we studied a male monozigotic twin pair discordant for GID (male-to-female) using VBM and SBM (FreeSurfer). We found increased grey matter volume and thicker cortex in the right temporo-parietal junction, right inferior frontal cortex and right insular cortex in the affected twin in comparison to his brother. The present study adds the findings on cortical thickness to the characterization of the neuroanatomic alterations in Gender Identity Disorder.
28

Neurofunctional and Neuroanatomical Hippocampal Deficits and Connectivity Differences in Schizophrenia Compared to Healthy Control Participants Tested on a Virtual Reality Navigation Wayfinding Task: An fMRI, VBM and Effective Connectivity Study

Ledoux, Andrée-Anne January 2013 (has links)
Episodic memory is a key feature in learning. One must remember past events to act upon a present situation. Episodic memory has been reported to be impaired in individuals with schizophrenia. In order to have an intact episodic memory the contextual features (context) must be bound to the content of the event; this mechanism is referred to as contextual binding. It is proposed that binding errors during the encoding process are responsible for episodic memory impairments in schizophrenia. Since the hippocampal formation is considered to be the central element for contextual binding, it is hypothesized that the synaptic disorganization described in this condition results in such a deficit. Moreover, the hippocampus mediates and influences other cognitive processes such as learning and executive functioning. Hence, a contextual binding deficit can have important consequences on cognition, behaviour and emotions. The object of this dissertation was to investigate the neurofunctioning, neuroanatomy and neurofunctional connectivity of the hippocampus while performing a task that utilized contextual binding mechanisms. Since spatial relational processing is part of contextual binding and is rooted in the hippocampal regions, visuospatial navigation, more precisely a wayfinding task, was used as a probe to activate the hippocampus and its associated regions in a group of patients with schizophrenia and matched healthy controls. The following dissertation presents three original research papers contributing to our understanding of the contextual binding and hippocampal deficits in schizophrenia. The first paper investigates the neurofunctioning of the hippocampus with a wayfinding task. The second paper investigates the hippocampal structural abnormality in schizophrenia and how it relates to performance during the wayfinding task. The third paper explores effective connectivity of the hippocampus with other brain regions involved in navigation in schizophrenia with a particular interest in the prefrontal cortex. These three studies demonstrate significant neurofunctional, neuroanatomical, and neurofunctional connectivity deficits in the hippocampus of the patients with schizophrenia compared to a healthy control population. Results of all three papers are further discussed in terms of research and clinical implications.
29

A Multimodal Magnetic Resonance Study of the Effects of Childhood Lead Exposure on Adult Brain Structure

Brubaker, Christopher John 15 September 2009 (has links)
No description available.
30

The Neural Correlates of Auditory Processing in Adults and Children who Stutter

Beal, Deryk Scott 05 August 2010 (has links)
This dissertation is comprised of four studies investigating the hypothesis that adults and children who stutter differ from their same-age fluent peers in the neuroanatomy and neurophysiology underlying auditory speech processing. It has been consistently reported that adults who stutter demonstrate unique functional neural activation patterns during speech production, including reduced auditory activation, relative to nonstutterers. The extent to which these functional differences are accompanied by abnormal morphology of the brain in stutterers is unclear. The first study in this dissertation examined the neuroanatomical differences in speech-related cortex between adults who do and do not stutter using magnetic resonance imaging and voxel-based morphometry analyses. Adults who stutter were found to have localized grey matter volume increases in auditory and motor speech related cortex. The second study extended this line of research to children who stutter, who were found to have localized grey matter volume decreases in motor speech related cortex. Together, these studies suggest an abnormal trajectory of regional grey matter development in motor speech cortex of people who stutter. The last two studies investigated the mechanism underlying the repeated findings of reduced auditory activation during speech in people who stutter in more detail. Magnetoencephalography was used to investigate the hypothesis that people who stutter have increased speech induced suppression of early evoked auditory responses. Adults and children who stutter demonstrated typical levels of speech induced suppression relative to fluent peers. However, adults and children who stutter showed differences from peers in the timing of cortical auditory responses. Taken together, the studies demonstrate structural and functional abnormalities in brain regions related to auditory processing and point to the possibility that people who stutter have difficulty forming the neural representations of speech sounds necessary for fluent speech production.

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