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PHYSIOLOGICAL CHARACTERISTICS IN COTTON GENOTYPES AS AFFECTED BY PLANT AGE AND PLANTING DENSITIES.MU'ALLEM, ABUBAKER SALEM. January 1987 (has links)
Physiological characteristics of three cotton genotypes were evaluated for their responses to plant aging under high and low planting density (HPD and LPD) treatments. In addition, the relationship of these physiological characteristics to fruit production were determined. Two genotypes are sympodia producing, "Pima S-6" (Gossypium barbadense L.) and "Deltapine 90" (DPL-90) (G. hirustum L.). The third, a "Cluster Selection" (G. barbadense L.) does not produce sympodia. These genotypes were grown on a Gila sandy loam soil at Tucson, Arizona in 1984 and 1985. Plant physiological characteristics were measured under field conditions at 5 intervals. Leaf physiological characteristics were determined at 7 different leaf ages. LPD treatment significantly reduced total dry weight (TDW), fruit dry weight (FDW), and leaf area index (LAI) in each genotype, but reductions were more pronounced in Pima S-6 and Cluster Selection in both seasons. However, LPD treatment significantly increased plant leaf area, but had no effect on specific leaf weight (SLW), petiole nitrate-nitrogen (Petiole NO₃-N) concentration, leaf area ratio (LAR), and fruiting index (FI), for all genotypes in both seasons. The aging patterns of all physiological characteristics were similar in both planting density treatments, regardless of genotype or season. Regression analyses showed that photosynthetic rate was curvilinearly correlated with leaf age (r² = 0.65 to 0.77, P < 0.01). However, petiole NO₃-N concentration decreased linearly with increasing leaf age (r² = 0.90 to 0.91, P < 0.01). Photosynthetic rate increased curvilinearly with increasing petiole NO₃-N concentration (r² = 0.61 to 0.79, P < 0.01). SLW was not correlated with leaf age, or other leaf physiological characteristics regardless of planting density treatment in 1985. TDW, FI, and LAI were directly related, while petiole NO₃-N concentration and LAR were inversely related to fruit production for all genotypes in both seasons. Multiple regression analyses showed that excluding planting density treatment effect, TDW, FI, and LAI were the most important variables incorporated for fruit prediction in both seasons.
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Factors Influencing the Uptake of Community-based Palliative CareDudley, Nancy Elizabeth 09 July 2016 (has links)
<p> Over the past ten years, community-based palliative care (CBPC) has rapidly expanded as older adults are living in the community longer with advanced illness and high symptom burden. Yet there are no models of standardized care for this population. It has been suggested that primary and secondary palliative care be delivered in the primary care setting to address palliative care needs in the community. However, a description of older adults in primary care with advanced illness and symptom burden who would benefit from primary and secondary palliative care, and a description of the process to deliver care are lacking. The aim of this dissertation was to explore the facilitators and barriers to providing palliative care in primary care, and to describe the prevalence of advanced illness and symptoms of older adults in primary care to identify who would benefit from palliative care in primary care. </p><p> Using a grounded theory methodology, twenty semi-structured interviews were conducted with primary care and palliative care providers in academic and community settings. Four major themes emerged from the data that are facilitators and barriers in care coordination: (i) role clarity; (ii) feedback and communication; (iii) time constraint and workforce; (iv) education. </p><p> A secondary analysis was conducted using the National Ambulatory and Hospital Medical Care Surveys 2009-2011 to examine primary care visits. There were more visits by older adults to primary care for advanced illness and symptoms than to non-primary care. More visits were due to advanced COPD, CHF, dementia, pain, depression, anxiety, fatigue, and insomnia compared to non-primary care. This research contributes to our knowledge of the delivery of palliative care in the community and the patient population that could benefit from primary and specialty palliative care. I offer a conceptual model of the process of primary care and specialty palliative care in order to coordinate care for older adults with advanced illness and progressive symptomatology. </p>
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Hypertension, Infection and Inflammation and their Effects on Memory and Visuospatial Skills in AgeingColledge, Alexander January 2016 (has links)
Blood pressure has previously been associated with decline in memory over time, though the exact mechanism behind this effect is uncertain. Infections, which can lead to systemic inflammation have also been linked to some cardiovascular damage to the brain, known as microbleeds, which have themselves been linked to greater declines in cognition in old age. The present study investigates whether blood pressure, a self-reported history of infection, and an indirect measure of inflammation known as the erythrocyte sedimentation rate have any association with on episodic and semantic memory and visuospatial skills in the Betula study, a Swedish longitudinal population study. The effect of elevated blood pressure (over 140 mm Hg systolic and/or 90 mm Hg diastolic), high blood sedimentation (top 33% against bottom 33% of participants), and self-reported infection were all found to not have any significant effect on episodic memory, semantic memory or visuospatial skills. Some of the possible explanations are elaborated in the discussion. / Högt blodtryck har associerats med minnesnedsättning men den exakta mekanismen hur ett samband kan förstås är dock oklar. Infektioner har visat sig ge systematiska inflammationer och har också satts i samband med vissa kardiovaskulära förändringar i hjärnan, så kallade mikroblödningar, vilka i sig har associerats med ökad risk för kognitive nedsättning i hög ålder. Denna uppsats syftar till att undersöka om blodtryck och infektion (självrapporterad infektion samt infektion indirekt mätt genom sänkereaktion) kan relateras till episodiskt och semantisk minne samt visuospatial förmåga i Betula studien, som är en svensk longitudinell populationsbaserad studie. Resultatet visade att varken högt blodtryck (över 140 mm Hg systoliskt eller 90 mm Hg diastoliskt), hög sänkereaktion (de 33 % med högst värde jämfört med de 33 % med lägst värde) eller självrapporterad infektion hade någon signifikant effekt för episodiskt minne, semantiskt minne eller visuospatial förmåga. Några möjliga förklaringar till detta resultat utvecklas i diskussionen. / The Betula Study
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Heterochronic Parabiosis Studies of the Aging Immune SystemDavies, John Stephen January 2016 (has links)
Parabiosis is the surgical union of two organisms resulting in the development of a single, shared circulatory system. When animals of different ages are conjoined (i.e. heterochronic parabiosis), blood-borne factors from the parabionts can affect the physiology of the other parabiont. This is manifested sometimes by beneficial, rejuvenating impact upon the older animal's tissues and organs (anti-geronic effect), and sometimes by younger animal's tissues regressing and appearing old-like (pro-geronic effect). These effects, and the ability to identify individual factors that could recapitulate pro- and anti-geronic effects, have made heterochronic parabiosis a very attractive approach to studying biology of aging and rejuvenation.cHowever, heterochronic parabiosis has not been widely used to investigate the aged immune system. An important question to be answered is whether the cellular defects involved in the aged immune system are due to intrinsic defects or if they can be rescued by extrinsic factors. Heterochronic parabiosis is ideal to test cellular migration patterns, interrogate the mechanisms driving migration defects that occur with aging, establish if these defects can be rejuvenated and identify molecules that are targets for intervention. Here, we provide evidence of the importance of reducing differences in the background genetics of different C57BL/6 substrains prior to parabiosis. This improvement allowed us to improve survival and confirm robust lymphocyte equilibration across secondary, but not primary, lymphoid tissues. We found no evidence for rejuvenation of the old immune cells, whereas results suggested that adult peripheral lymph nodes (pLN) lost mass and cellularity, potentially indicating the presence of a pro-geronic factor(s) in the old circulation that affects pLN function. Adult and old immune cells were present in equal frequencies in both adult and old secondary lymphoid tissues, indicating that there was no restriction of cellular migration due to the age of the cell or age of the tissue. The propensity of adult immune cells (i.e. large naïve compartment) to occupy lymph nodes and old immune cells (i.e. large memory compartment) to occupy bone marrow was retained following heterochronic parabiosis. Finally, parabiosis separation experiments illuminated the peripheral survival advantage of old T cells over adult T cells. These results highlight the power of heterochronic parabiosis in studying immune aging and provide hypothesis-generating data for future mechanistic studies of peripheral T cell maintenance with aging.
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Health Literacy Among Elderly Hispanics and Medication UsageParker, Wilda Y. 04 June 2016 (has links)
<p> Health literacy among the elderly Hispanics is a problem for 44% who read at the lowest level due to issues with recognition, cognition, or vision. The purpose of this study was to determine the extent that elderly Hispanics have problems with medication adherence due to health literacy. The social cognitive theory was the framework for this study. Inclusion criteria consisted of being 65-75 years of age, and speaking and/or reading English and/or Spanish. Questionnaires from 156 individuals were completed in Cobb County/Atlanta GA and analyzed using multiple regression to determine the relationship between health literacy and medication usage. Medication adherence was the dependent variable and independent variables were gender, age, Hispanic origin, education, income, income means, health insurance, health literacy, and medication usage. Statistical significance was noted in medication adherence, health literacy, and working full-time. Results were based on the correct answers from health literacy questions, which showed an association between medication adherence and health literacy and a reduction in medication adherence problems among elderly Hispanics who worked full-time. These findings showed a significant association between medication adherence and health literacy level among elderly Hispanics. No medication adherence problems were noted among participants who had good health literacy, unlike participants with poor health literacy. A larger ethnic group may show a variation of problems in future studies. Implications for social change could include recommendations for the use of Spanish language hotlines and reading materials to provide care, knowledge, and medication information assistance.</p>
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Modeling Non-Linear Relationships Between DNA Methylation And Age: The Application of Regularization Methods To Predict Human Age And The Implication Of DNA Methylation In ImmunosenescenceJohnson, Nicholas 13 May 2016 (has links)
Background: Gene expression is regulated via highly coordinated epigenetic changes, the most studied of which is DNA methylation (DNAm). Many studies have shown that DNAm is linearly associated with age, and some have even used DNAm data to build predictive models of human age, which are immensely important considering that DNAm can predict health outcomes, such as all-cause mortality, better than chronological age. Nevertheless, few studies have investigated non-linear relationships between DNAm and age, which could potentially improve these predictive models. While such investigations are relevant to predicting health outcomes, non-linear relationships between DNAm and age can also add to our understanding of biological responses to late-life events, such as diseases that afflict the elderly.
Objectives: We aim to (1) examine non-linear relationships between DNAm and age at specific loci on the genome and (2) build upon regularization methods by comparing prediction errors between models with both non-transformed and square-root transformed predictors to models that include only non-transformed predictors. We used both the sparse partial least squares (SPLS) regression model and the lasso regression model to make our comparisons.
Results: We found two age-differentially methylated sites implicated in the regulation of a gene known as KLF14, which could be involved in an immunosenescent phenotype. Inclusion of the square-root transformed variables had little effect on the prediction error of the SPLS model. On the other hand, the prediction error increased substantially in the lasso regression model, particularly when few predictors (70) were included.
Conclusion: The growing amount and complexity of biological data coupled with advances in computational technology are indispensable to our understanding of biological pathways and perplexing biological phenomena. Moreover, high-dimensional biological data have enormous implications for clinical practice. Our findings implicate a possible biological pathway involved in immunosenescence. While we were unable to improve the predictive models of human age, future research should investigate other possible non-linear relationships between DNAm and human age, considering that such statistical methods can improve predictions of health outcomes.
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Age-related deficits in inhibition in figure-ground assignmentAnderson, John A. E., Healey, M. Karl, Hasher, Lynn, Peterson, Mary A. 06 May 2016 (has links)
We assessed age differences in the ability to resolve competition for figural status in stationary displays using small, enclosed, symmetrical silhouettes that participants classified as depicting "novel'' or "familiar'' shapes. The silhouettes were biased such that the inside was perceived as the shaped figure, and the outside was perceived as a shapeless ground. The critical manipulation was whether a portion of a meaningful object was suggested on the outside of the border of some of the novel silhouettes but not others M(+)Ground and M-Ground novel silhouettes, respectively). This manipulation was intended to induce greater inhibitory competition for figural status from the groundside in M(+)Ground silhouettes than M(-)Ground silhouettes. In previous studies, young adults classified M(+)Ground silhouettes as "novel'' faster than M(-)Ground silhouettes (Trujillo, Allen, Schnyer, & Peterson, 2010), suggesting that young adults may recruit more inhibition to resolve figure-ground when there is more competition. We replicated this effect with young adults in the present study, but older adults showed the opposite pattern and were less accurate in classifying M(+)Ground than M(-)Ground silhouettes. These results extend the evidence for inhibitory deficits in older adults to figure assignment in stationary displays. The (M(+)Ground - M(-)Ground) RT differences were evident in observers' longest responses, consistent with the hypothesis that inhibitory deficits are evident when the need for inhibition is substantial.
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African American grandparents residing in a nursing facility| Perceptions of influence with their grandchildren, family, and communityBester, Monica 21 May 2015 (has links)
<p> African American older adults have historically been identified as vital members of the African American family and community (Hill, 1972; Cox, 2002; Waites, 2008). Unfortunately, research has shown an increasing number of older African Americans are being admitted into nursing facilities (Paul, 2004; Feng et al., 2011). Between the years of 1998-2008, it was projected African Americans living in nursing homes increased by 10.8% (Feng et al., 2011). This study explores the intergenerational relationships of older African American adults with their grandchildren, family, and community through the lens of Intergenerational Family Systems Theory. By viewing this qualitative study through the lens of Intergenerational Family Systems Theory, changes in the older adults’ kinscripts were analyzed to obtain a greater understanding of affects associated with nursing home relocation and the older adults’ relationship with their grandchildren, family, and communities since being admitted. By utilizing a grounded theory approach, this study has found key areas to influence future social work practice and research.</p>
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The influence of lipid rafts on aging and immunologyFeng, Haoqi 2009 August 1900 (has links)
Lipid rafts are operationally defined as cholesterol-rich membrane microdomains resistant to solubilization in nonionic detergents at low temperatures. Lipid rafts, which are quite different in lipid composition from the surrounding membranes, are of great importance to signal transduction, protein sorting and membrane transport. They have been implicated in a range of biosynthetic and endocytic processes and systems-signaling, molecular trafficking, diseases as well as being involved in the immune, vascular, digestive and reproductive systems. Dietary nutrients like fatty acids and vitamins of different types also play a critical and decisive role in the regulation of lipid rafts. / text
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Speaking through the “open-ers” : how age feminizes Chaucer’s ReeveWaymack, Anna Fore 08 October 2014 (has links)
The Reeve’s Prologue in Chaucer’s Canterbury Tales represents one of the most prominent medieval narratives of old age. In his bitter tirade the Reeve emphasizes the topics of impotence, sexuality, power and voice through a series of metaphors involving horses, leeks, coals, and medlar fruit. Though the Prologue itself has been extensively discussed, little of the discussion has been in the context of age studies. Nor have scholars paid much attention to the medlar, called by its colloquial name “open-ers.” The Reeve chooses to describe himself and other older men through this unmistakably sexualized and repulsive term, raising paradoxical issues of rottenness and ripeness. He uses the medlar to resist fourteenth-century age culture and reconfigure his identity into a submissive, open one. Where impotence has removed agency and voice, this new identity enables a feminized voice, a claim to desire, and an ability to quyte the Miller for what the Reeve perceived as an ageist story meant to mock him. However, a Lacanian reading suggests that in grappling with his impotence, the Reeve has come to realize the futility of signifying and the difficulties of expressing desire. The Reeve’s Prologue thus exposes the breakdown of desire in the Reeve’s Tale and raises larger questions about the influence of older age on tale-telling, especially in a masculine register. / text
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