• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2321
  • 1837
  • 473
  • 273
  • 153
  • 95
  • 58
  • 45
  • 43
  • 28
  • 24
  • 23
  • 17
  • 17
  • 17
  • Tagged with
  • 6244
  • 1706
  • 811
  • 655
  • 596
  • 523
  • 481
  • 408
  • 403
  • 390
  • 386
  • 345
  • 340
  • 337
  • 337
  • 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.
371

The relationship of ageism and life satisfaction in a large intergenerational group of adults

Davis, Neil Carter. January 2006 (has links)
Thesis (Ed.D.)--University of West Florida, 2006. / Title from title page of source document. Document formatted into pages; contains 95 pages. Includes bibliographical references.
372

Epigenetic effects of learning and memory in the I-Ppo-I mouse

Balta, Ana-Maria 03 November 2016 (has links)
The epigenetics of the aging brain is a growing field of study that holds great promise for the discovery of mechanisms and potential treatments for neurodegenerative diseases. In this current study, a novel, accelerated aging murine model, the I-PpoI/Cre, or ICE (Inducible Changes in the Epigenome) mouse, is studied to test its potential for demonstrating the theory of the rearrangement of chromatin (RCM) as the main cause of aging, and in particular, the mechanism through which the brain ages. Immunohistochemistry and behavioral assays are utilized to determine whether there are morphological changes, inflammatory response, and changes in learning and memory. Results showed a significant increase in microglia and astrocytes, markers of inflammation, in I-PpoI/Cre mice compared to their Cre controls. Long term memory performance was also significantly decreased in the I-PpoI/Cre mice, demonstrated through contextual fear conditioning (CFC) testing, and Morris Water Maze (MWM) testing. Results from this study are in support of the I-PpoI/Cre mouse as a model of accelerated aging of the brain, with deficits in learning and memory. Further studies are needed to further characterize this murine model of accelerated aging.
373

The effects of age and education on selected cognitive tests: the trail making test, the digit symbol sub-test, and the finger tapping test

Stewart, Maureen January 2003 (has links)
Numerous studies have suggested that neuropsychological test performance is affected by demographic variables such as age and education. This study examined the effects of age and education on the Trail Making Test, the Digit Symbol Sub-Test, and the Finger Tapping Test in a non-clinical sample of community dwellers with a relatively low level of education (8 to 12 years) in South Africa. The sample consisted of 161 participants across six age groups: 20-39, 40-59, 69-69, 70-79, 80-89 and 90-95 years. Results were examined for mean age effects and variability trends. Highly significant age effects were present across the age groups for all tests, however, there was no uniform pattern of variability across the tests. The Digit Symbol Substitution Test and the Finger Tapping Tests showed a pattern of increasing variability with increasing age, followed by a decrease in very old age while no trend was evident for the Digit Symbol extensions (the Immediate and Delayed Recall tests). The Trail Making Test, Parts A and B, showed a consistent trend of increasing variability across the age groups. Data from the present study was compared with existing data from two relatively high education samples, with equivalent age groupings, to examine education effects. Results showed an education effect for all tests with the high education groups outperforming the low education groups. Although the effects of education became less potent with advancing age, the mean performance of the oldest (80-89 years) high education age group was superior to that of the equivalent low education age group. Comparison of variability trends across both samples showed that the highest variability (the shuttle bulge) was present at the same point along the age axis, or at a later point, for the low education group, as that for the high education group. This finding is inconsistent with Jordan's (1997) 'shuttle model of variability' which predicts an earlier occurrence of the shuttle bulge (left shuttle shift effect) for a low education sample. This study demonstrated that performance on neuropsychological tests is influenced by age and education and highlighted the dangers inherent in unquestionably applying norms, which have not been corrected for age and education, when assessing the older adult.
374

Inclusive fitness: participatory design approaches for active ageing

Futerman, Rael Glen January 2007 (has links)
Thesis (MTech (Industrial Design))--Cape Peninsula University of Technology, 2007 / This thesis tests the Usability, Safety and Attractiveness Participatory Design model (USAP) in the field of inclusive fitness. The focus is on improving compatibility between elderly people and fitness products. Three participatory design (PO) workshops were carried out with potential users ranging from 20 to 80 years of age. The research not only includes current elderly people but also those who will be entering this age bracket in the next ten years. Although the main focus is on the elderly, younger participants were included, and acted as a transgenerational audit. The first PO session made known possible avenues for exploration; the second session introduced a new group of people to the research and acted as a check to see if a wider audience of older users had similar needs to those uncovered so far; the third session involved middle age participants who will be entering old age in the next ten years. Concepts were generated and participants commented and critiqued them.
375

Non-Poissonian statistics, aging and "blinking'" quantum dots.

Aquino, Gerardo 08 1900 (has links)
This dissertation addresses the delicate problem of aging in complex systems characterized by non-Poissonian statistics. With reference to a generic two-states system interacting with a bath it is shown that to properly describe the evolution of such a system within the formalism of the continuous time random walk (CTRW), it has to be taken into account that, if the system is prepared at time t=0 and the observation of the system starts at a later time ta>0, the distribution of the first sojourn times in each of the two states depends on ta, the age of the system. It is shown that this aging property in the fractional derivative formalism forces to introduce a fractional index depending on time. It is shown also that, when a stationary condition exists, the Onsager regression principle is fulfilled only if the system is aged and consequently if an infinitely aged distribution for the first sojourn times is adopted in the CTRW formalism used to describe the system itself. This dissertation, as final result, shows how to extend to the non-Poisson case the Kubo Anderson (KA) lineshape theory, so as to turn it into a theoretical tool adequate to describe the time evolution of the absorption and emission spectra of CdSe quantum dots. The fluorescence emission of these single nanocrystals exhibits interesting intermittent behavior, namely, a sequence of "light on" and "light off" states, departing from Poisson statistics. Taking aging into account an exact analytical treatment is derived to calculate the spectrum. In the regime fitting experimental data this final result implies that the spectrum of the "blinking" quantum dots must age forever.
376

Development and Testing of the Elderly Social Vulnerability Index (ESVI): A Composite Indicator to Measure Social Vulnerability in the Jamaican Elderly Population

Crooks, Donneth 27 February 2009 (has links)
Over the last two decades social vulnerability has emerged as a major area of study, with increasing attention to the study of vulnerable populations. Generally, the elderly are among the most vulnerable members of any society, and widespread population aging has led to greater focus on elderly vulnerability. However, the absence of a valid and practical measure constrains the ability of policy-makers to address this issue in a comprehensive way. This study developed a composite indicator, The Elderly Social Vulnerability Index (ESVI), and used it to undertake a comparative analysis of the availability of support for elderly Jamaicans based on their access to human, material and social resources. The results of the ESVI indicated that while the elderly are more vulnerable overall, certain segments of the population appear to be at greater risk. Females had consistently lower scores than males, and the oldest-old had the highest scores of all groups of older persons. Vulnerability scores also varied according to place of residence, with more rural parishes having higher scores than their urban counterparts. These findings support the political economy framework which locates disadvantage in old age within political and ideological structures. The findings also point to the pervasiveness and persistence of gender inequality as argued by feminist theories of aging. Based on the results of the study it is clear that there is a need for policies that target specific population segments, in addition to universal policies that could make the experience of old age less challenging for the majority of older persons. Overall, the ESVI has displayed usefulness as a tool for theoretical analysis and demonstrated its potential as a policy instrument to assist decision-makers in determining where to target their efforts as they seek to address the issue of social vulnerability in old age. Data for this study came from the 2001 population and housing census of Jamaica, with multiple imputation for missing data. The index was derived from the linear aggregation of three equally weighted domains, comprised of eleven unweighted indicators which were normalized using z-scores. Indicators were selected based on theoretical relevance and data availability.
377

Age and vigilance: The effects of event rate and task pacing

Mohney, Jack D. 01 January 1986 (has links)
No description available.
378

Community acquired bacteraemia in the elderly / Community acquired bacteraemia in the elderly

Whitelaw, D A, Whitelaw, D A 10 July 2017 (has links)
Age affects the human frame at all levels - from the skin which is ravaged by exposure to ultraviolet light and toxic irritants to the immune system which becomes progressively less responsive to antigenic stimuli. Bacteraemia follows a focal infection and thus any change which results in increased infection will result in an increased chance of bacteraemia. Therefore any factors bearing on focal infection will, of necessity influence not only the possibility but also the severity of a bacteraemia.
379

Gut Bacterial Load Associates with Dramatic Declines in Anoxia Tolerance in Young Drosophila melanogaster Adults

January 2020 (has links)
abstract: Anoxia tolerance is strongly correlated with tolerance to heat, desiccation, hyperosmotic shock, freezing, and other general stressors, suggesting that anoxia tolerance is broadly related to stress tolerance. Age affects the capacity of many animals to survive anoxia, but the basis to this ontogenic variation is poorly understood. We exposed adult Drosophila, 1, 3, 5, 7, 9, and 12 days past eclosion, to six hours of anoxia and assessed survival 24-hours post-treatment. Survival of anoxia declined strongly with age (from 80% survival for one-day-old flies to 10% survival for 12 day-old-flies), a surprising result since adult fly senescence in Drosophila is usually observed much later. In anoxia, adenosine triphosphate (ATP) levels declined rapidly (< 30 min) to near-zero levels in both 1 and 12-day old adults; thus the higher anoxia-tolerance of young adults is not due to a better capacity to keep ATP elevated. Relatively few physiological parameters are reported to change over this age range in D. melanogaster, but gut bacterial content increases strongly. As a partial test for a causal link between bacterial load and anoxia tolerance, we replaced food daily, every third day, or every sixth day, and assayed survival of six hours of anoxia and bacterial load at 12 days of age. Anoxia tolerance for 12-day old flies was improved by more food changes and was strongly and negatively affected by bacterial load. These data suggest that increasing bacterial load may play an important role in the age-related decline of anoxia tolerance in Drosophila. / Dissertation/Thesis / Masters Thesis Biology 2020
380

Regulation Of Hematopoietic Stem Cells By Lipid and Mitochondrial Metabolism

Sharma, Devyani 15 June 2020 (has links)
No description available.

Page generated in 0.094 seconds