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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.
351

On the use of modelling, observations and remote sensing to better understand the Canadian prairie soil-crop-atmosphere system

Brimelow, Julian Charles 07 April 2011 (has links)
Thunderstorms have been identified as an important component of the hydrological cycle on the Canadian Prairies, a region that is postulated to have the potential to exert a detectable influence on convective precipitation in the summer. However, very little work has been undertaken exploring and elucidating those aspects of biophysical forcing on the Canadian Prairies that affect lightning activity during the summer months, the constraints under which any linkages operate, and the mechanisms by which surface anomalies modify the structure and moisture content of the convective boundary layer (CBL) so as to modulate lightning activity. Evapotranspiration (ET) from the soil and vegetation canopy is known to be important for modulating the moisture content in the CBL, and this in turn has important implications for the initiation and intensity of deep, moist convection. The Second Generation Prairie Agrometeorological Model (PAMII) of Raddatz (1993) has been used extensively for the purpose of quantifying the evolution of soil moisture and ET in response to atmospheric drivers on the Canadian Prairies. However, the ability of PAMII to simulate the evolution of root-zone soil moisture and ET during the growing season has yet to be verified against a comprehensive set of in-situ observations. In this thesis, we address the above knowledge gaps using unique datasets comprising observed lightning flash data, satellite-derived Normalized Difference Vegetation Index (NDVI) data, observed atmospheric soundings, in-situ soil moisture observations and estimates of daily ET from eddy-covariance systems. A thorough quantitative validation of simulations of root-zone soil moisture and ET from PAMII was undertaken against in-situ soil moisture measurements and ET from eddy-covariance systems at sites on the Canadian Prairies. Our analysis demonstrates that PAMII shows skill in simulating the evolution of bulk root-zone soil moisture content and ET during the growing season, and for contrasting summer conditions (i.e., wet versus dry). As part of the soil moisture validation, a novel multi-model pedotransfer function ensemble technique was developed to quantify the uncertainty in soil moisture simulations arising from errors in the specified soil texture and associated soil hydraulic properties. An innovative approach was used to explore linkages between the terrestrial surface and deep, moist convection on the Canadian Prairies, using datasets which avoid many of the problems encountered when studying linkages between soil moisture and thunderstorm activity. This was achieved using lightning flash data in unison with remotely sensed NDVI data. Specifically, statistical analysis of the data over 38 Census Agricultural Regions (CARs) on the Canadian Prairies for 10 summers from 1999 to 2008 provided evidence for a surface-convection feedback on the Canadian Prairies, in which drought tends to perpetuate drought with respect to deep, moist convection. The constraints in which such a feedback operates (e.g., areal extent and magnitude of the NDVI anomalies) were also identified. For example, our data suggest that NDVI anomalies and lightning duration are asymmetric, with the relationship between NDVI and lightning duration strengthening as the area and amplitude of the negative NDVI anomaly (less vegetation vigour) increases. Finally, we focused on how surface anomalies over the Canadian Prairies can condition the CBL so as to inhibit or facilitate thunderstorm activity, while also considering the role of synoptic-scale forcing on modulating summer thunderstorm activity. We focused on a CAR located over central Alberta for which observed lightning flash data, NDVI data, and in-situ sounding data were available for 11 summers from 1999 to 2009. Our analysis suggests that storms over this region are more likely to develop and are longer-lived or more widespread when they develop in an environment in which the surface and upper-air synoptic-scale forcings are synchronized. On days when a surface or upper-air feature is present, storms are more likely to be triggered when NDVI is much above average, compared to when NDVI is much below average. We propose a conceptual model, based almost entirely on observations, which integrates our findings to describe how a reduction in vegetation vigour modulates the partitioning of available energy into sensible and latent heat fluxes at the surface, thereby modulating the lifting condensation level heights, which in turn affect lightning duration.
352

Cough Reflex Testing in Acute Dysphagia Management: Validity, Reliability and Clinical Application

Miles, Anna Clare January 2013 (has links)
Silent aspiration is associated with pneumonia and mortality, and is poorly identified by traditional clinical swallowing evaluation (CSE). Currently, there is no reliable test for detecting silent aspiration during CSE. There is, however, increasing evidence for the validity of cough reflex testing (CRT) for identifying silent aspiration. This test has the potential to significantly improve clinical assessment of dysphagia. The aim of this research programme was to further investigate the validity, reliability and clinical utility of CRT for identifying patients at risk of silently aspirating. Several aspects of CRT were explored during this research programme. Two correlational studies were conducted to validate CRT for identifying silent aspiration against videofluoroscopic swallowing study (VFSS) and flexible endoscopic evaluation of swallowing (FEES). Cough reflex threshold testing was completed on 181 patients using inhaled, nebulised citric acid. Within one hour, 80 patients underwent VFSS and 101 patients underwent FEES. All tests were recorded and analysed by two researchers blind to the result of the alternate test. Significant associations between CRT result and cough response to aspiration on VFSS (p = .003) and FEES (p < .001) were identified. Sensitivity and specificity were optimised at 0.6mol/L in patients undergoing VFSS (71%, 60% respectively) and at 0.4mol/L in patients undergoing FEES (69%, 71% respectively). A concentration of 0.8mol/L had the highest odds ratio (OR) for detecting silent aspiration (8 based on VFSS, 7 based on FEES). Coughing on lower concentrations of citric acid (0.4mol/L compared with 1.2mol/L) was a better predictive measure of silent aspiration. Diminished cough strength has also been associated with aspiration and increased risk of pneumonia. Reflexive cough is our primary defensive mechanism against aspiration and a measure of reflexive cough strength therefore holds greater relevance than one of voluntary cough strength. Despite common use and clinical applicability, the reliability of subjective cough judgements has received little attention. The inter- and intra-rater reliability of subjective judgements of cough in patients following inhalation of citric acid was assessed. Forty-five speech-language therapists (SLTs) were recruited to the first study. Of these, 11 SLTs were currently using CRT in their clinical practice (experienced raters) and 34 SLTs reported no experience with CRT (inexperienced raters). Participants provided a rating of strong, weak or absent to ten video segments of cough responses elicited by inhalation of nebulised citric acid. The same video segments presented in a different sequence were re- evaluated by the same clinicians following a 15-minute break. Inter-rater reliability for experienced raters was calculated with a Fleiss’ generalised kappa of .49; intra-rater reliability was higher with a kappa of .70. Inexperienced raters showed similar reliability with kappa values for inter-rater and intra-rater reliability of .36 and .62, respectively. SLTs demonstrated only fair to moderate reliability in subjectively judging a patient’s cough response to citric acid. Experience in making cough judgements did not improve reliability significantly. In a second study, specific training in cough physiology and cough judgement was provided to 58 trained SLTs. Inter-rater reliability of subjective judgements of cough in patients following inhalation of citric acid was assessed. Participants provided a rating of present or absent, and if present then a rating of strong or weak, to ten video segments of cough responses. Inter-rater reliability for cough presence was calculated with a Fleiss’ generalised kappa of .71 and cough strength was calculated at .61. Years of clinical experience did not improve inter-rater reliability significantly. Experience in using CRT did improve inter-rater reliability. Further validity and reliability research would be beneficial for guiding clinical guidelines and training programmes. By identifying patients at risk of silent aspiration, more informed management decisions can be made that consequently lead to a reduction in preventable secondary complications such as pneumonia. The clinical utility of CRT for reducing pneumonia in acute stroke patients was assessed through a randomised, controlled trial. Three hundred and eleven patients referred for swallowing evaluation were assigned to either 1) a control group receiving standard evaluation or 2) an experimental group receiving standard evaluation with CRT. Participants in the experimental group were administered nebulised citric acid with test results contributing to clinical decisions. Outcomes for both groups were measured by pneumonia rates at three months post stroke and other clinical indices of swallowing management. Analysis of the data identified no significant differences between groups in pneumonia rate (p = .38) or mortality (p = .15). Results of CRT were shown to influence diet recommendations (p < .0001) and referrals for instrumental assessment (p <.0001). Despite differences in clinical management between groups, the end goal of reducing pneumonia in post stroke dysphagia was not achieved. Through this research, the characteristics and outcomes associated with dysphagia secondary to stroke in New Zealand were identified. Baseline characteristics of 311 patients with dysphagia following acute stroke were collected during their hospital stay and outcomes were measured at three months post stroke. Mortality rates were 16% and pneumonia rates 27%. Mean length of stay was 24 days and only 45% of patients were in their own home at three months post stroke. Pneumonia was significantly associated with mortality and increased length of stay. Only 13% of patients received referral for instrumental assessment of swallowing. These data are discussed in reference to the National Acute Stroke Services Audit 2009 and internationally published data. The outcomes for stroke patients with dysphagia in New Zealand are poor with a high risk of pneumonia and long hospital stays when compared internationally. In summary, this research programme has contributed to our understanding of the use of CRT in patients with dysphagia. The addition of a measure of reflexive cough strength may add to clinical assessment but specific training is required to reach adequate reliability. CRT results are significantly associated with aspiration response on instrumental assessment and lower concentrations of citric acid provide a better predictive measure of silent aspiration. CRT can be standardised and therefore is not as susceptible to interpretative variance that plagues much of CSE. Sensitivity and specificity values using this CRT methodology are adequate for CRT to be incorporated into clinical protocols. Inclusion of CRT alone was not shown to be sufficient to change clinical outcomes however integration of CRT into clinical pathways may prove more successful. Further research evaluating the addition of CRT to a comprehensive CSE would add greatly to the field of dysphagia assessment.
353

PROCESS OPTIMIZATION AND VALIDATION OF AN ASSAY FOR HIGH-THROUGHPUT SCREENING

Ravindranath, Padma Priya 01 January 2006 (has links)
A biological assay is designed to set up a rapid and robust drug-screening system on a small scale. An assay is considered as a single unit of a platform to screen various compounds for aiding in drug discovery. Each assay is carried out in a 96-well plate, each of whose wells consists of the biological component called the Spheroids. The value of each assay lies in it facilitating for versatile screening applications. The spheroid is considered as a micro-structural product. And the addition of various compounds for testing is performed in each well (consisting of the spheroids). The focus has been to put forth the production principles and validation strategies to run the biological assay and test its efficacy to be used for screening in high volumes. The assay development illustrates processing and validation techniques. The goal is to develop optimized standards to process the assay, addressing various quality control issues, from the raw material to the end-product stage. Such an approach also brings interesting analogies of biological process in a manufacturing scenario. The developed system incorporates a value stream approach, by pulling the product from the customer end. The process involves simply encapsulating HUVECs (Human Umbelical Vein Endothelial cells) from the raw material stage, culturing to form the spheroid and transferring the component to assemblage in a 96-well format undergoing stages of heat treatments. The small scale screening system allows the use of small amounts of drug, which is especially essential for new drug synthesis or in rapid decision making to find out any unknown potent compounds. The design of optimal processes in product development of the spheroid assay is illustrated. Thus in light of the value of this assay, developing the production system has been pivotal so as to produce quality spheroids in the 96-well plate formats. The quantification of the stimulatory and inhibitory effects of the different agents is required to help understand the complex biological behavior involved. The goal is to validate the data using image analysis software. The image analysis helps determine the quantification to be accurate, objective, and consistent. The quality of the product is tested by the reproducibility and robustness of the assay.
354

TESTING AND VALIDATION OF A CORRELATION BASED TRANSITION MODEL USING LOCAL VARIABLES

Likki, Srinivas Reddy 01 January 2004 (has links)
A systematic approach of testing and validating transition models is developed and employed in testing of a recently developed transition model. The testing methodology uses efficient computational tools and a wide range of test cases. The computational tools include a boundary layer code, single zone Navier Stokes solver, and a multi-block Navier Stokes solver which uses MPI and is capable of handling complex geometries and moving grids. Test cases include simple flat plate experiments, cascade experiments, and unsteady wake/blade interaction experiments. The test cases are used to test the predicting capabilities of the transition model under various effects such as free stream turbulence intensity, Reynolds number variations, pressure gradient, flow separation, and unsteady wake/blade interaction. Using the above test cases and computational tools a method is developed to validate transition models. The transition model is first implemented in boundary layer code and tested for simple flat plate cases. Then the transition model is implemented in single zone Navier Stokes solver and tested for hysteresis effects for flat plate cases. Finally the transition model is implemented in multi zone Navier Stokes solver and tested for compressor and turbine cascade cases followed by unsteady wake/blade interaction experiments. Using the method developed a new correlation based transition model (Menter et al. 2004) which uses local variables is tested and validated. The new model predicted good results for high free stream turbulence and high Reynolds number cases. For low free stream turbulence and low Reynolds number cases, the results were satisfactory.
355

Error and occurrence analysis of Stanfins redesign at Computer Sciences Corporation

Khan, Irshad A. January 1990 (has links)
At Ball State University Dr. Wayne Zage and Professor Dolores Zage are working on a Design metrics project to develop a metrics approach for analyzing software design.The purpose of this thesis is to test the hypotheses of this metric by calculating the De external design component, and to show the correlation of errors and stress points in the design phase for a large Ada Software, professionally developed at Computer Sciences Corporation.From these studies we can relatively conclude that De does indicate the error-prone module. Since the D(G) is comprised of an internal and external component it is necessary to evaluate Di to support this hypothesis on a large project. Just by viewing the external complexity, the metric does a relatively good job of pointing out high error modules, with only viewing 10% of the modules we found 33% of the errors.Comparing the results of STANFINS-R and the results of the BSU projects, the BSU projects did better in finding the errors 33% verus 53%. However in the STANFINS project, we had a better success rate of finding the error modules. Of the modules highlighted 72% did contain errors. Thus if we loosened the criteria for selection of error prone modules we might have had a large percentage of the errors captured. / Department of Computer Science
356

Validation of the Canadian Precipitation Analysis (CaPA) for Hydrological Modelling in the Canadian Prairies

Zhao, KuangYin 27 November 2013 (has links)
Traditional hydrological model inputs are often deemed inadequate in areas where stations are sparse, such as the northern extents of the Canadian Prairie basins. The Canadian Precipitation Analysis (CaPA) combines GEM (Global Environmental Multi-scale model) data and available observation data to provide enhanced precipitation estimates. The CaPA analysis has recently been extended to produce high-resolution precipitation data over the Canadian Prairies, encompassing the Nelson-Churchill River Basin. Manitoba Hydro and other water practitioners in Manitoba have expressed interest in potentially using CaPA precipitation as hydrological model forcing for Prairie watersheds. A three step validation approach was designed and applied to assess CaPA for hydrologic modelling applications in the Nelson-Churchill River basin. Results of validation show that the quality of CaPA data varies among regions and seasons, with CaPA proving beneficial in both data-sparse regions and winter seasons most prominently. Overall, CaPA shows promise for water resource application in the Canadian Prairies.
357

Employee Engagement Construct and Instrument Validation

Witemeyer, Hazen A 11 May 2013 (has links)
Employee engagement is a relatively new construct in academic literature and an increasingly popular idea in practice. Proponents of employee engagement claim a strong positive relationship between engagement and business success, both at the firm and individual levels, and outcomes including retention, productivity, profitability, and customer loyalty and satisfaction. Despite numerous academic and practitioner publications on employee engagement, no consistently-accepted conceptualization of the construct or its sub-dimensions exists, and there is an ongoing debate regarding whether the employee engagement construct is a new idea or a re-hashing of old ideas. Similarly, no consistently-accepted tool to measure employee engagement exists. In the absence of consistent conceptualization and measurement, relationships between employee engagement and its antecedents and outcomes cannot be empirically tested. Drawing on prior literature and practitioner interviews, the present study defines employee engagement as an attitude towards one’s work at one’s company, comprising feelings of vigor, dedication, and absorption; cognitive appraisals of psychological empowerment; and motivation to act, both within role and extra role, in the service of the organization’s goals. In addition, the present study validates a self-report instrument to measure this conceptualization of employee engagement, using construct and scale validation procedures accepted in marketing and information systems literature.
358

On the use of modelling, observations and remote sensing to better understand the Canadian prairie soil-crop-atmosphere system

Brimelow, Julian Charles 07 April 2011 (has links)
Thunderstorms have been identified as an important component of the hydrological cycle on the Canadian Prairies, a region that is postulated to have the potential to exert a detectable influence on convective precipitation in the summer. However, very little work has been undertaken exploring and elucidating those aspects of biophysical forcing on the Canadian Prairies that affect lightning activity during the summer months, the constraints under which any linkages operate, and the mechanisms by which surface anomalies modify the structure and moisture content of the convective boundary layer (CBL) so as to modulate lightning activity. Evapotranspiration (ET) from the soil and vegetation canopy is known to be important for modulating the moisture content in the CBL, and this in turn has important implications for the initiation and intensity of deep, moist convection. The Second Generation Prairie Agrometeorological Model (PAMII) of Raddatz (1993) has been used extensively for the purpose of quantifying the evolution of soil moisture and ET in response to atmospheric drivers on the Canadian Prairies. However, the ability of PAMII to simulate the evolution of root-zone soil moisture and ET during the growing season has yet to be verified against a comprehensive set of in-situ observations. In this thesis, we address the above knowledge gaps using unique datasets comprising observed lightning flash data, satellite-derived Normalized Difference Vegetation Index (NDVI) data, observed atmospheric soundings, in-situ soil moisture observations and estimates of daily ET from eddy-covariance systems. A thorough quantitative validation of simulations of root-zone soil moisture and ET from PAMII was undertaken against in-situ soil moisture measurements and ET from eddy-covariance systems at sites on the Canadian Prairies. Our analysis demonstrates that PAMII shows skill in simulating the evolution of bulk root-zone soil moisture content and ET during the growing season, and for contrasting summer conditions (i.e., wet versus dry). As part of the soil moisture validation, a novel multi-model pedotransfer function ensemble technique was developed to quantify the uncertainty in soil moisture simulations arising from errors in the specified soil texture and associated soil hydraulic properties. An innovative approach was used to explore linkages between the terrestrial surface and deep, moist convection on the Canadian Prairies, using datasets which avoid many of the problems encountered when studying linkages between soil moisture and thunderstorm activity. This was achieved using lightning flash data in unison with remotely sensed NDVI data. Specifically, statistical analysis of the data over 38 Census Agricultural Regions (CARs) on the Canadian Prairies for 10 summers from 1999 to 2008 provided evidence for a surface-convection feedback on the Canadian Prairies, in which drought tends to perpetuate drought with respect to deep, moist convection. The constraints in which such a feedback operates (e.g., areal extent and magnitude of the NDVI anomalies) were also identified. For example, our data suggest that NDVI anomalies and lightning duration are asymmetric, with the relationship between NDVI and lightning duration strengthening as the area and amplitude of the negative NDVI anomaly (less vegetation vigour) increases. Finally, we focused on how surface anomalies over the Canadian Prairies can condition the CBL so as to inhibit or facilitate thunderstorm activity, while also considering the role of synoptic-scale forcing on modulating summer thunderstorm activity. We focused on a CAR located over central Alberta for which observed lightning flash data, NDVI data, and in-situ sounding data were available for 11 summers from 1999 to 2009. Our analysis suggests that storms over this region are more likely to develop and are longer-lived or more widespread when they develop in an environment in which the surface and upper-air synoptic-scale forcings are synchronized. On days when a surface or upper-air feature is present, storms are more likely to be triggered when NDVI is much above average, compared to when NDVI is much below average. We propose a conceptual model, based almost entirely on observations, which integrates our findings to describe how a reduction in vegetation vigour modulates the partitioning of available energy into sensible and latent heat fluxes at the surface, thereby modulating the lifting condensation level heights, which in turn affect lightning duration.
359

Collaborative supply chain modelling and performance measurement

Angerhofer, Bernhard J. January 2002 (has links)
For many years, supply chain research focused on operational aspects and therefore mainly on the optimisation of parts of the production and distribution processes. Recently, there has been an increasing interest in supply chain management and collaboration between supply chain partners. However, there is no model that takes into consideration all aspects required to adequately represent and measure the performance of a collaborative supply chain. This thesis proposes a model of a collaborative supply chain, consisting of six constituents, all of which are required in order to provide a complete picture of such a collaborative supply chain. In conjunction with that, a collaborative supply chain performance indicator is developed. It is based on three types of measures to allow the adequate measurement of collaborative supply chain performance. The proposed model of a collaborative supply chain and the collaborative supply chain performance indicator are implemented as a computer simulation. This is done in the form of a decision support environment, whose purpose is to show how changes in any of the six constituents affect collaborative supply chain performance. The decision support environment is configured and populated with information and data obtained in a case study. Verification and validation testing in three different scenarios demonstrate that the decision support environment adequately fulfils it purpose.
360

Antihistamininių vaistų (klemastino fumarato, loratadino, desloratadino) mišinio išskyrimas iš kraujo plazmos ir identifikavimas efektyviosios skysčių chromatografijos metodu / Antihistamines (clemastine fumarate, loratadine, desloratadine) extraction from human plasma and identification using high performance liquid chromatography

Zdanytė, Birutė 30 June 2014 (has links)
Darbo tikslas: optimizuoti metodiką, kuria būtų galima atlikti antihistamininių vaistų mišinio, sudaryto iš klemastino fumarato, loratadino ir desloratadino, ekstrakciją iš kraujo plazmos ir kokybinį nustatymą efektyviosios skysčių chromatografijos metodu. Darbo uždaviniai: Atlikti mokslinės literatūros analizę siekiant įvertinti antihistamininių vaistų savybes ir pasirinktų junginių ekstrakcijos iš kraujo plazmos ir tapatybės nusatymo metodikas. Optimizuoti ir validuoti ESC metodiką kokybiniam pasirinktų preparatų mišinio nustatymui iš kraujo plazmos. Parinkti klemastino fumarato, loratadino ir desloratadino skysčių – skysčių ekstrakcijos iš kraujo plazmos sąlygas. Apibendrinti gautus ekstrakcijos ir ESC rezultatus. Metodai: skysčių – skysčių ekstrakcija ir ESC. Tyrimo objektas: kraujo plazma, į kurią įterpti antihistamininiai vaistai klemastino fumaratas, loratadinas, desloratadinas ir jų mišinys. Rezultatai: tiriamųjų medžiagų sulaikymo laikai: desloratatadino apie – 5,9 min, loratadino – apie 11,4 min, klemastino fumarato – apie 13,2 min. Validuota ESC atlikimo metodika. Atliekant ekstrakciją su trichlormetanu neišsiekstrahavo nei vienas tiriamasis junginys, su dichlormetanu – loratadinas, su dietileteriu ir cikloheksanu – visi trys tiriamieji junginiai. Išvados: 1. Atlikta mokslinės literatūros analizė, apžvelgiant antihistamininių vaistų savybes, ekstrakcijos iš kraujo plazmos būdus bei identifikavimo metodus, didžiausią dėmesį skiriant efektyviajai skysčių... [toliau žr. visą tekstą] / Aim: to optimise a method, by which mixture of antihistamines containing clemastine fumarate, loratadine and desloratadine could be extracted from human plasma and qualitative determination using high performance liquid chromatogrophy could be made. Tasks: to carry out analysis of scientific literature and evaluate characteristics of antihistamines and methods of chosen compounds extraction from human plasma and identity determination. Optimise and validate HPLC method for qualitative determination of chosen medicines. Select conditions suitable for chosen antihistamines liquid – liquid extraction from human plasma. Carry out qualitative determination of clemastine fumarate, loratadine and desloratadine in human plasma using validated HPLC method. Summarize results of extraction and HPLC. Methods: liquid – liquid extraction and HPLC. Object: human plasma with embedded antihistamines: clemastine fumarate, loratadine, deloratadine and their mixture. Results: retention times of test substances: desloratadine – 5,9 min, loratadine – 11,4 min, clemastine fumarate – 13,2 min. HPLC method was validated. None of the compounds were extracted using trichlormethan. Only loratadine was extracted using dichlormethan. All three compounds were extracted using diethyl ether and cyclohexane. Conclusions: 1. Analysis of scientific literature was caried out, characteristics of antihistamines, methods of extraction from human plasma and identity determination of chosen compounds were overviewed... [to full text]

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