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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.
1

When prudence is reckless : rethinking the role of project risk management : a 152.785 (25 point) research report presented in partial fulfilment of the requirements for the degree of Master of Management at Massey University

Busch, Adrian Unknown Date (has links)
Despite the widespread use of project risk management, the results of such efforts are often underwhelming. Do project risk management practices somehow miss the point? To explore this idea I use a critical management studies framework to study project risk management. The approach prescribed in the Project Management Institute's Project Management Body of Knowledge is compared to the very different approach of a professional project manager. A theorised analysis of the difference between these approaches finds that they employ the logic of different knowledge-constitutive interests thereby making them suitable for different purposes. The study concludes with a discussion of how the results of this analysis can be presented to practitioners in a way consistent with the emancipatory agenda of critical management studies.
2

Attentional Uncertainty in the Stroop Priming Task

Johnson, Brandy Nicole 01 May 2009 (has links)
There is extensive evidence that structures in the anterior attentional system (i.e. dorsolateral prefrontal cortex and anterior cingulate) are susceptible to normal aging processes, whereas structural changes in the posterior attentional system are minimal. Using the Stroop priming task, we investigated whether reducing the involvement of the anterior attentional system by pre-cuing the location of the target stimulus would eliminate age differences in interference. Older adults continued to be susceptible to interference when the location cue was ambiguous or invalid, but were less susceptible when the target location of a stimulus was presented with a valid cue.
3

Effects of Aging on Adipose Resistance Artery Vasoconstriction: Possible Implications for Orthostatic Blood Pressure Regulation

Ramsey, Michael W., Behnke, Bradley J., Prisby, Rhonda D., Delp, Michael D. 01 November 2007 (has links)
The purpose of this investigation was to determine mean arterial pressure (MAP) and regional vascular conductance responses in young and aged Fisher-344 rats during orthostatic stress, i.e., 70° head-up tilt (HUT). Both groups demonstrated directionally different changes in MAP during HUT (young, 7% increase; aged, 7% decrease). Vascular conductance during HUT in young rats decreased in most tissues but largely remained unchanged in the aged animals. Based on the higher vascular conductance of white adipose tissue from aged rats during HUT, resistance arteries from white visceral fat were isolated and studied in vitro. There was diminished maximal vasoconstriction to phenylephrine and norepinephrine (NE: young, 42 ± 5%; old, 18 ± 6%) in adipose resistance arteries from aged rats. These results demonstrate that aging reduces the ability to maintain MAP during orthostatic stress, and this is associated with a diminished vasoconstriction of adipose resistance arteries. With advancing age the ability to tolerate orthostatic stress (17, 22) and perform exercise (11, 15, 34) is reduced. One possible mechanism for these age-related changes is a diminished arterial vasoconstrictor responsiveness, which could impair redistribution of cardiac output during exercise and limit reductions in vascular conductance during orthostasis. The ability to diminish vascular conductance in nonactive tissue is requisite during orthostasis to maintain mean arterial pressure (MAP) and sustain adequate brain perfusion. However, whether regional vascular conductance during orthostasis is altered by aging remains unknown. Head-up tilt (HUT) has been utilized extensively to study cardiovascular system responsiveness to orthostatic stress in humans and animals (8, 13, 14, 16, 26, 31). Postural changes from the supine position to the upright posture elicit a blood volume shift from the thoracic cavity to the lower limbs (29), which results in reduced venous return and, subsequently, decreased stroke volume. The resultant decrease in cardiac output must be offset by a decrease in peripheral vascular conductance (PVC) to maintain arterial blood pressure (29). Since there is a greater incidence of orthostatic hypotension with advancing age (16, 25, 31, 38), the primary purpose of the present study was to determine whether a diminished ability to maintain MAP during an orthostatic stress is manifest in aged Fischer-344 rats and to identify whether alterations in regional vascular conductance correspond to a putative orthostatic hypotension. Specifically, we hypothesized that with HUT, aged animals will demonstrate a diminished vasoconstriction in some tissues, as evidenced by higher blood flows and vascular conductance relative to that in young adult rats. The results indicated an inability of old rats to diminish vascular conductance in several tissues, including white adipose tissue, during HUT. Therefore, a secondary purpose was to test the hypothesis that aging diminishes myogenic and adrenergic vasoconstriction of resistance vessels from white visceral adipose tissue. The results from this series of experiments may indicate an underlying mechanism for the old age-related orthostatic intolerance. Given that adipose tissue makes up a greater proportion of body composition with aging in rats (7) and humans (1), a reduced vasoconstriction of resistance vessels from this tissue could have significant ramifications on the ability to decrease peripheral vascular conductance during orthostatic challenges and with exercise among the elderly.
4

Cross-sectional and longitudinal analyses of the effects of aging on memory in healthy young, middle-aged, and oldest-old adults : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Pyschology at Massey University, Palmerston North, New Zealand

Lamont, Allison Unknown Date (has links)
While a growing body of research indicates that older adults typically perform more poorly on many types of memory tasks than do younger adults, relatively little research has addressed the question of whether this trend continues unchanged into the late ninth and tenth decades of life. Such decrements in memory have been reported as linear declines from early adulthood up until about 80 years of age. Questions arise as to whether such memory declines slow or accelerate in very advanced aging, and to what extent differences are due to aging, per se, or variables that intervene between age and memory.To address these two questions, six memory types - verbal recall, nonverbal recall, short-term memory, working memory, face recognition, and prospective memory - were examined using both cross-sectional and longitudinal methodologies. The six types of memory and the influence of verbal processing speed, nonverbal processing speed, and intelligence were examined in mixed-gender groups of 20 - 40 (n = 40, M = 30.7, SD = 5.52), 50 - 70 (n = 44, M = 59.2, SD = 4.94), and 85+ year olds (n = 42, M = 87.8, SD = 2.43), at two points, the second occurring two years after the first. Each participant completed tests of word recall, geometric shapes recall, short-term memory (digit span), working memory (letter-number sequencing), face recognition, and prospective memory. Additionally, there were two processing speed tasks (Identical Pictures and Finding As), and the National Adult Reading Test of verbal fluency was used to estimate intelligence. The Mini-Mental State Examination and the Beck Depression Inventory (BDI-II) were used to screen for dementia and depression, respectively.At Time 1 testing the 85+ participants showed declines in all memory types (compared to the 20 - 40 year olds). Nonverbal recall (66.2% lower than the young group), working memory (46.2%), verbal recall (45%), and prospective memory (38.2%) produced the largest differences, short-term memory (12.3%) and face recognition (14.7%) the least. Two years later, the 85+ years old participants had shown further declines, relative to the 20 - 40 years group. Nonverbal recall (72.3% lower than the young group), prospective memory (63.2%), working memory (55.3%), and verbal recall (54.7%) continued to produce the largest decrements, with short-term memory (18.9%) and face recognition (19.8%) the least. The results for the young and middle participants did not change appreciably between Time 1 and Time 2. The difference between unadjusted scores and scores adjusted for intelligence, verbal processing speed, and nonverbal processing speed, increased markedly between Time 1 and Time 2 testing for the oldest-old participants.These findings support the view that while memory declines may be approximately linear from age 20 to 80 years, there is a sharp decline in most types of memory after the age of 85 years, recall and working memory suffering the most. Intelligence and processing speed have an effect on some types of memory, but age is by far the largest contributor to memory decline. Furthermore, as expected, all memory types declined over the two-year period, with prospective memory, verbal recall, nonverbal recall, and working memory showing the greatest declines. Short-term memory and face recognition declined at a noticeably slower rate.
5

An fMRI comparison between younger and older adults of neural activity associated with recognition of familiar melodies

Sikka, Ritu 16 September 2013 (has links)
We investigated age-related differences in neural activation associated with recognition of familiar melodies, a process that requires retrieval from musical semantic memory and leads to a feeling of familiarity. We used sparse sampling fMRI to determine the neural correlates of melody processing and familiarity by comparing activation when listening to melodies versus signal-correlated noise, and to familiar versus unfamiliar melodies, respectively. Overall, activity in the bilateral superior temporal gyrus correlated well with melody processing. Familiarity was associated with several frontal regions (bilateral inferior frontal gyrus, superior frontal gyrus, and precentral gyrus; left insular cortex), right superior temporal gyrus; left supramarginal gyrus and cingulate gyrus; bilateral putamen and thalamus; cerebellum and brainstem. No significant differences were found between younger and older adults for either melody processing or familiarity based activation. Assessment of familiarity-related group differences using less stringent criteria identified plausible areas; greater activation was seen bilaterally in the superior temporal gyrus in younger adults and in some left parietal regions in older adults. This study adds to the knowledge of musical semantic memory with results based on a large sample (N = 40) that includes older adults. Our findings for activation associated with melody processing and familiarity support some, but not all, previous results of related studies. We were unable to find conclusive evidence of age-related differences in neural correlates of musical semantic memory, while also being the first study (to the best of our knowledge) to search for these differences. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-09-16 12:38:10.757
6

An fMRI comparison between younger and older adults of neural activity associated with recognition of familiar melodies

Sikka, Ritu 16 September 2013 (has links)
We investigated age-related differences in neural activation associated with recognition of familiar melodies, a process that requires retrieval from musical semantic memory and leads to a feeling of familiarity. We used sparse sampling fMRI to determine the neural correlates of melody processing and familiarity by comparing activation when listening to melodies versus signal-correlated noise, and to familiar versus unfamiliar melodies, respectively. Overall, activity in the bilateral superior temporal gyrus correlated well with melody processing. Familiarity was associated with several frontal regions (bilateral inferior frontal gyrus, superior frontal gyrus, and precentral gyrus; left insular cortex), right superior temporal gyrus; left supramarginal gyrus and cingulate gyrus; bilateral putamen and thalamus; cerebellum and brainstem. No significant differences were found between younger and older adults for either melody processing or familiarity based activation. Assessment of familiarity-related group differences using less stringent criteria identified plausible areas; greater activation was seen bilaterally in the superior temporal gyrus in younger adults and in some left parietal regions in older adults. This study adds to the knowledge of musical semantic memory with results based on a large sample (N = 40) that includes older adults. Our findings for activation associated with melody processing and familiarity support some, but not all, previous results of related studies. We were unable to find conclusive evidence of age-related differences in neural correlates of musical semantic memory, while also being the first study (to the best of our knowledge) to search for these differences. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2013-09-16 12:38:10.757

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