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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.
141

A preliminary study on the effect of selective serotonin reuptake inhibitors on peripheral and lower brainstem auditory processing.

Carney, Lara E. 05 1900 (has links)
This study compared auditory behavioral and physiologic measures in normal control subjects and subjects prescribed with a selective serotonin reuptake inhibitor (SSRI) who were yet to take the drug and those currently taking an SSRI. Test measures used were pure tone averages (PTA), acoustic reflex thresholds, uncomfortable loudness levels (UCL), otoacoustic emissions, masking level difference, temporal integration, amplitude resolution, and Beck Depression Inventory-II (BDI-II) scores. Results indicated that there was a significant difference in the amplitude resolution of the unmedicated group when compared to the medicated and the control group. There was also a significant positive correlation between dynamic range (difference between UCL and PTA) and amplitude resolution. The BDI-II revealed a significant difference between the scores of the unmedicated and the control group as well as the medicated and the control group. Although other test measures indicated differences between the groups, the differences were not statistically significant.
142

The kinetics of the work capacity above critical power

Skiba, Philip Friere January 2014 (has links)
The critical power (CP) model includes two constants: the CP and the W′ [P = W′ / t) + CP]. The W′ is the finite work capacity available above CP. Power output above CP results in depletion of the W′; complete depletion of the W′ results in exhaustion. It is possible to model the charge and discharge of the W′ during intermittent exercise using a novel integrating model (the W′BAL model), and to generate a function describing a curvilinear relationship between time constants of reconstitution of the W′ in terms of the difference between recovery power and CP (DCP) (r2 = 0.77). The depletion of the W′ as predicted by the W′BAL model during intermittent exercise is linearly related to the rise in V ̇O_2 above exercise baseline (r2 = 0.82 – 0.96). During intermittent exercise, the W′BAL model is generally robust with respect to the length of work and recovery interval, yielding a mean under-prediction of the W′BAL of only -1.6 ±1.1 kJ. The amount of W′ remaining after a period of intermittent exercise correlates with the difference between the subject’s V ̇O_2 at that time (V ̇O_2START) and V ̇O_2PEAK (DVO2) (r = 0.79, p < 0.01). Moreover, the W′BAL model also performs well in the field, permitting accurate estimation of the point at which an athlete becomes exhausted during hard training or competition (mean W′BAL at exhaustion = 0.5 ± 1.3 kJ (95% CI = 0 – 0.9 kJ). The W′BAL model meets the mathematical criteria of an excellent diagnostic test for exhaustion (area under ROC curve = 0.91). 31P magnetic resonance spectroscopy during single leg extensor exercise revealed a correlation between the recovery of the W′BAL model and recovery of creatine phosphate ([PCr]) after a bout of exhaustive single leg extensor exercise (r = 0.99, p < 0.01). The W′BAL model also accurately predicted recovery of the W′ in this setting (r = 0.97, p < 0.05). However, a complete understanding of the relationship between the depletion and recovery of [PCr] and the depletion and recovery of the W′ remains elusive. Muscle carnosine content is curvilinearly related to the rate of W′BAL recovery, with higher muscle carnosine associated with faster recovery, with implications for muscle buffering capacity and calcium handling. The W′BAL model may be recast in the form of a differential equation, permitting definition of the time constant of recovery of the W′BAL in terms of the subject’s known W′ and the DCP. This permits the scaling of the model to different muscle groups or exercise modalities. Moreover, modifications to this mathematical form may help explain some of the variability noted in the model in earlier studies, suggesting novel avenues of research. However, the present formulation of the W′BAL model is mathematically robust and represents an important addition to the scientific armamentarium, which may aid the understanding the physiology of human performance.
143

Earlier snowmelt reduces atmospheric carbon uptake in midlatitude subalpine forests

Winchell, Taylor S., Barnard, David M., Monson, Russell K., Burns, Sean P., Molotch, Noah P. 16 August 2016 (has links)
Previous work demonstrates conflicting evidence regarding the influence of snowmelt timing on forest net ecosystem exchange (NEE). Based on 15years of eddy covariance measurements in Colorado, years with earlier snowmelt exhibited less net carbon uptake during the snow ablation period, which is a period of high potential for productivity. Earlier snowmelt aligned with colder periods of the seasonal air temperature cycle relative to later snowmelt. We found that the colder ablation-period air temperatures during these early snowmelt years lead to reduced rates of daily NEE. Hence, earlier snowmelt associated with climate warming, counterintuitively, leads to colder atmospheric temperatures during the snow ablation period and concomitantly reduced rates of net carbon uptake. Using a multilinear-regression (R-2=0.79, P<0.001) relating snow ablation period mean air temperature and peak snow water equivalent (SWE) to ablation-period NEE, we predict that earlier snowmelt and decreased SWE may cause a 45% reduction in midcentury ablation-period net carbon uptake.
144

Comparative Phyto-uptake Across Distribution Coefficients of Pharmaceutical Compounds and Aquatic Macrophytes: Carbamazepine and Amiodarone Uptake in Lemna Spp

Woodard, Jennifer Kristin 08 1900 (has links)
Few studies have been conducted on the effectiveness of phytoremediation of pharmaceutical compounds, although the persistent and non-acutely toxic nature of many of these compounds in today's water bodies may yield an ideal application for this practice. To quantify the potential effectiveness of plant uptake, kinetic and proportional bioconcentration factors (BCFk, and BCFp, respectively) in nanograms (ng) carbamazepine and amiodarone per gram (g) wet weight plant tissue for Lemna spp. were determined utilizing a 14-day continuous flow-through study. Samples were analyzed using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) running in positive ion mode. Kinetic BCF was estimated at 0.538, while proportional BCF was estimated at 0.485. Kinetic BCF for the amiodarone study was estimated at 23.033, whereas proportional BCF was estimated at 41.340. Possible contamination of the C18 column and peristaltic pump failure may have impacted uptake results. In light of variability and current lack of research in the field, this work should be considered exploratory rather than conclusive.
145

Warming and water deficit impact the nutritional performance of a C4 and C3 tropical grass /

Viciedo, Dilier Olivera January 2019 (has links)
Orientador: Renato de Mello Prado / Abstract: Global warming is predicted to increase the intensity and duration of extreme weather events, such as droughts, heat waves, and floods, especially in tropical regions. Climate change affect growth of forage species. However, information regarding the effects of global climate change on the nutritional performance of tropical pastures is lacking, especially under field conditions. We, thus, conducted two field experiment with Panicum maximum and Stylosanthes capitata using a temperature free-air controlled enhancement system and evaluated the effects of two temperature conditions, ambient temperature and moderate warming (2°C above ambient canopy temperature), and two levels of water availability, irrigated and non-irrigated, on nutrients accumulation, nutrient use efficiency (NUE), the stoichiometric patterns of C:N:P and leaf biomass production. Both experiments was conducted using a randomized complete block design in a factorial arrangement. Our findings revealed in plants of P. maximum (C4- grass) that the N and P leaf concentration greatly decreased under water-stressed, which increased the C:N and C:P ratios, while warming increased the N:P ratio. Leaf biomass production was impaired by up to 16% under water stress and ambient temperature conditions, but the biomass production was improved by 20% under warming and irrigated conditions. Our results also showed that homeostatic instability under rainfed conditions resulted in decreased leaf biomass production, and it was ... (Complete abstract click electronic access below) / Resumo: Prevê-se que o aquecimento global aumente a intensidade e a duração dos eventos climáticos extremos, como secas, ondas de calor e inundações, especialmente nas regiões tropicais. Mudanças climáticas afetam o crescimento de espécies forrageiras. No entanto, faltam informações sobre os efeitos das mudanças climáticas globais no desempenho nutricional de pastagens tropicais, especialmente em condições de campo. Nós, assim, conduzimos dois experimento em campos com as forrageiras Panicum maximum e Stylosanthes capitata utilizando um sistema de temperatura controlada do aquecimento do ar (T-Face) e avaliou-se os efeitos de duas condições de temperatura, (temperatura ambiente) e aquecimento moderado (2°C acima da temperatura ambiente) e dois níveis de disponibilidade hídrica, (irrigada e não irrigados), no acúmulo de nutrientes, eficiência de uso de nutrientes (NUE), nos padrões estequiométricos de C:N:P e na produção de biomassa foliar. Ambos experimentos foram conduzidos utilizando um delineamento de blocos completos casualizados em arranjo fatorial. Nossos resultados revelaram que em plantas de P. maximum (pastagem C4) a concentração foliar de N e P diminuiu sob estresse hídrico, o que aumentou as relações C:N e C:P, enquanto o aquecimento aumentou a relação N:P. A produção de biomassa foliar foi prejudicada em até 16% sob condições de estresse hídrico e temperatura ambiente, mas a produção de biomassa foi melhorada em 20% sob condições de aquecimento e irrigação. Nossos resulta... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor
146

Correlates of contraceptive non-use among married women in Nigeria.

Fisayo, Popoola Titilope 05 September 2014 (has links)
Contraceptive non-use by women has been linked to negative reproductive health outcomes such as obstetric complications, abortions, and maternal morbidity and mortality. These poor outcomes mostly arise from unintended pregnancies. With focus on married women non-users, this study examined the factors influencing non-use of contraception in Nigeria. The research identified a number of important characteristics which could predispose married women in Nigeria to non-use of contraceptive. Data from the 2008 Nigeria Demographic and Health Survey (NDHS) was utilized. The target population comprised all females aged 15-49 years who were interviewed and responded to questions on contraceptive use. The sample size was 23,954 which were made up of all married women in the country except for infecund, pregnant and sterilized women. The outcome variable was measured using current contraceptive use which was dichotomized: not using contraceptive coded as (1) and using contraceptive coded as (0). Logistic regression was used for the analysis. 20,983 married women (88% of the study population) reported that they are contraceptive non-users. Of these, the following characteristics of married women had higher odds of contraceptive non-use. Women who want more children within 2years, unsure of timing and undecided had higher odds (2.17) of contraceptive non-use, women who are 35 years and above (1.80), women who are from North West, North East and North Central (5.35, 2.95, 1.64, respectively), women who are Muslims (1.43) had higher odds of contraceptive non-use in Nigeria. The association remained statistically significant for women’s wealth index, number of living children, occupation, and place of residence, partner’s education and educational level of women. And all these were also observed to have effect on the non-use of contraceptive. Non-use of contraceptive among married women in Nigeria differs between women possibly because of region, religion, fertility intention, and age difference. These findings indicate areas that reproductive health policies and programmes should focus on in order to increase contraceptive uptake among married women in Nigeria. .
147

Curva de crescimento e acúmulo de nutrientes em híbridos de cebola /

Noda, Sayuri Beatriz Hara, 1993. January 2018 (has links)
Orientador: Dirceu Maximino Fernandes / Coorientador: Ricardo Lima dos Santos / Banca: Roberto Lyra Villas Bôas / Banca: Camila Paula Rossetto Pescatori Jacon / Resumo: As curvas de absorção de nutrientes e o acúmulo de matéria seca em função da idade da planta possibilitam conhecer os períodos de maior exigência dos nutrientes e de produção de massa de matéria seca, obtendo-se informações seguras quanto às épocas mais convenientes de aplicação de fertilizantes. Frequentemente, empresas privadas, empresas públicas e cooperativas estão desenvolvendo novos híbridos e cultivares de cebola adaptadas às variadas condições climáticas, com diferentes exigências nutricionais. Desse modo, são necessários estudos envolvendo as curvas de absorção de nutrientes dos diversos genótipos lançados, no sentido de aprimorar as recomendações de calagem e adubação. O objetivo do projeto foi obter a curva de absorção de nutrientes em híbridos de cebola em condições de campo. O projeto foi desenvolvido em parceria com a empresa Sakata Seed Sudamerica Ltda que forneceu o material utilizado para o experimento. As plantas amostradas periodicamente foram analisadas para os teores de macro e micronutrientes seguindo metodologia descrita na literatura. Os resultados dos teores de nutrientes foram multiplicados pela massa seca da parte aérea, bulbos e raízes, para gerar a quantidade de nutrientes contida nas plantas de cebola e assim, poder gerar a curva de absorção. Além disso, os bulbos colhidos foram analisados quanto às características físicas e químicas para fins de caracterização do material. De modo geral ambos os materiais se comportaram de modo semelhante quanto... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The absorption march of nutrients and the accumulation of dry matter through plant's growth stages provide information about periods of highest nutrient demand and dry mass production, obtaining reliable data on the most advantageous moment of application of fertilizers. Often, private companies, public companies and co-ops develop new onion hybrids and cultivars adapted to varied climate conditions with different nutritional requirements. Thus, researches about the nutrients absorption march of different cultivars are essential, in order to improve the liming and fertilization recommendations and to increase the onion yield. The purpose of this study was to determine the growth and nutrients uptake by two different onion hybrid plants under field conditions. The project was developed in partnership with the company Sakata Seed Sudamerica Ltda that provided the material used in the experiment and location. The plants collected were analyzed for macronutrients and micronutrients contents according to methodology described in literature. The analyses were done by the University's laboratory. The results of the analyses were multiplied by the dry matter of leaves, bulbs and roots, in order to obtain the amount of nutrients in the onion plants. Further, the harvested bulbs were analyzed for physical and chemical characteristics to characterization purposes. In general, both genotypes behaved similarly to nutrient accumulation. The amount of extraction presented relevant data for the management of the fertilization of the studied hybrids. The exported quantities showed that both materials were efficient in converting nutrients to bulb ... / Mestre
148

Effects of metal speciation on metal plant dynamics in the presence of plant growth promoting bacteria

Adele, Nyekachi Chituru January 2017 (has links)
Excessive metal deposition in soil is of major concern to the environment due to the toxicity of metals to animals and plants. Since metals do not degrade, reducing risk of exposure relies in either removing the metals from soil, or changing their speciation which leads to changes in bioavailability, mobility and toxicity. Plants have been shown to provide a cheap alternative to chemical methods for both removing and changing metal speciation, particularly when augmented with plant growth promoting bacteria. The focus of this thesis was to investigate whether the form (speciation) in which a metal contaminant is introduced to soil affects both plant health and the efficiency of metal remediation by the plant, using the well-known hyperaccumulator Brassica juncea (L.) Czern and zinc (Zn) as the metal contaminant. This study also examined the role of plant growth promoting bacteria in changing metal speciation, impact on metal toxicity and phytoremediation efficiency. Brassica juncea was grown in pots containing soil spiked with equal amounts (600 mg Zn kg-1) of soluble Zn (ZnSO4) and nanoparticulate ZnS and ZnO. Plant height, number of leaves, root length, plant biomass and chlorophyll content of Brassica juncea were used to assess Zn toxicity. Zn localisation and speciation in soil and plant tissues was studied using transmission electron microscopy (TEM), synchrotron micro-X-ray fluorescence elemental mapping (μXRF) and synchrotron X-ray absorption spectroscopy (XAS). Growth parameters showed that ZnSO4 was the most toxic form of Zn whilst ZnS and ZnO effects were not statistically different. These differences were linked to differences in Zn content in root and shoot biomass, which was higher in ZnSO4 treatments. Inoculation with Rhizobium leguminosarum and Pseudomonas brassicacearum enhanced plant growth, Zn concentration in plant biomass and translocation of Zn in all Zn treatments. XAS analysis showed that Zn speciation was altered in roots of plants inoculated with bacteria, with Zn cysteine as the most dominant form of Zn in all inoculated Zn treatments, suggesting a role for cysteine in ameliorating Zn toxicity. By also assessing Zn speciation changes across the soilrhizosphere- plant interface, this study established that Rhizobium leguminosarum modified Zn speciation at the rhizosphere. Through this thesis work, metal speciation is a major factor in determining the efficiency of metal phytoremediation and plant tolerance. Hence, this research provides useful information on Zn speciation which will contribute to effective implementation of Zn phytoremediation.
149

An investigation into the use of selective serotonin reuptake inhibitors for improving low lung function and pulmonary exacerbations

Armstrong, Hilary Farrar January 2018 (has links)
Chronic obstructive pulmonary disease (COPD) is characterized by periodic episodes of worsening symptom (e.g., shortness of breath, irregular breathing, and worse coughing with increased phlegm production), also called pulmonary exacerbations. Inflammation is an important cause of reduced lung function as inflammation contributes to airflow obstruction in the small airways and lung parenchyma. Even in individuals with mild COPD, inflammation reduces lung function, accelerates decline in lung function overtime, and increases the risk for respiratory exacerbations. Agents that reduce systemic inflammation are hypothesized to decrease the inflammation in the lungs, resulting in improvements in lung function and a decrease in exacerbation frequency. We hypothesize that antidepressants have a beneficial effect on lung function. In addition to having anti-inflammatory properties, antidepressants act upon serotonin, which is integral in central breathing control. The combination of the anti-inflammatory and serotonergic effects may provide users of selective serotonin reuptake inhibitors with a lung function benefit while avoiding the side effects of steroids. This dissertation assesses whether selective serotonin reuptake inhibitors increase concurrent lung function and reduce the risk for respiratory exacerbations. It consists of three parts: a systematic literature review and two analytic papers using large prospective databases. The systematic review of the literature identified limitations concerning the effect of selective serotonin reuptake inhibitors on lung function. Overall, the analytic papers found no support for a beneficial association between selective serotonin reuptake inhibitors and spirometry, dyspnea or pulmonary exacerbations; indeed the association was in the opposite direction as hypothesized. In addition, there was no support for meaningful mediation by inflammatory markers. Further research is needed to determine if selective serotonin reuptake inhibitors have a harmful effect on lung function and pulmonary exacerbations.
150

Role of OCRL1 in zebrafish early development and kidney function

Pietka, Grzegorz January 2013 (has links)
Mutations of the gene encoding the inositol polyphosphate 5-phosphatase OCRL1 are responsible for causing two disorders in humans: Lowe syndrome and type 2 Dent's disease (Dent-2). Lowe syndrome (oculocerebrorenal syndrome of Lowe) is an X-linked genetic disorder that causes multisystem defects affecting predominantly the eyes, brain and kidneys. Dent-2 disease is very similar to Lowe syndrome, but it affects primarily the kidneys with little or no symptoms in the brain and eyes. The enzymatic activity, structure and binding partners of the OCRL1 protein have been described and progress on the cellular functions of OCRL1 has been made. However the studies to date have not provided the necessary insight to explain the tissue-specific defects observed in Lowe syndrome and Dent-2 patients. In order to investigate the role of OCRL1 and the consequences of its deficiency in a physiological context an animal model is required. We have chosen the zebrafish for this study due to its suitability for investigating vertebrate early development and the abundance of research techniques available for this model organism. We have studied the expression of OCRL1 in zebrafish and its role in the early embryonic development. We have also investigated its role in the endocytic function of the zebrafish larval pronephric kidney. Finally we have investigated its role in ciliogenesis and function of pronephric cilia. Our studies show that OCRL1 depletion does not cause gross developmental defects, nor affects the development of pronephros, but impairs their endocytic activity. We have also shown, that efficient pronephric uptake requires OCRL1 interactions with clathrin, Rab GTPase family proteins, APPL1 and IPIP27A/B. Our studies link the reduced uptake with lowered levels of megalin receptor, which is responsible for the bulk of protein reabsorption in the kidney. Together our results strongly suggest that defects in this process are responsible for low molecular weight proteinuria present in Lowe syndrome and Dent-2 patients and zebrafish is a suitable model to study the renal aspect of these diseases.

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