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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.
401

Application of Monitored Natural Attenuation and Risk Assessment at a Chlorinated-compound Contaminated Site for Risk anagement

Tsai, Wei-anne 03 August 2009 (has links)
Contamination by dense non aqueous phase liquids (DNAPLs) [e.g., trichloroethylene (TCE)] in soil and groundwater has become an issue of great concern in many industrialized counties. In this study, a chlorinated-compound spill site was selected as the case study site to evaluate the possible risk to site workers and local residents caused by the contaminated soil and groundwater. The contaminants of concern at this site were TCE and 1,1-Dichloroethylene (1,1-DCE). The detected concentrations for TCE and 1,1-DCE exceeded the control standards of 0.05 and 0.07 mg/L, respectively. In this study, the Risk-based Corrective Action (RBCA) protocol developed by American Society for Testing and Materials (ASTM), health and risk assessment methods for soil and groundwater contaminated sites developed by Taiwan Environmental Protection Administration were applied for risk calculation and quantification. Monte Carlo analysis using @RISK software was applied for uncertainty analysis to calculate the cumulative risk at 95% probability distribution. Moreover, a natural attenuation model (BIOCHLOR) was used to evaluate the effectiveness of natural attenuation mechanisms on the chlorinated compounds. Results from this study show that the occurrence of natural attenuation for the chlorinated compounds was confirmed through the anaerobic biodegradation processes. The calculated cumulative risk at 95% cumulative probability via ingestion route was 2.61¡Ñ10-5 through the Monte Carlo analysis. The calculated cumulative risk at 95% cumulative probability via inhalation route and ambient (outdoor) vapor inhalation diffusion channels were 1.461¡Ñ10-5 and 2.17¡Ñ10-6, respectively. Because the calculated risk levels were higher than the target cancer risk is 1¡Ñ10-6 described in Taiwan¡¦s ¡§Soil and Groundwater Remediation Act¡¨, appropriate remedial actions are required to lower the risk to below the target level. Results also show that the calculated hazard index (HI) values of the contaminated site are lower than the acceptable level (HI < 1) described in the ¡§Soil and Groundwater Remediation Act.¡¨ To meet the target level of cancer risk of 1¡Ñ10-6, TCE contaminated groundwater needs to be remediated to below the site specific target level (SSTL) for inhalation exposure routes in a confined space volume, which is 6.91 ¡Ñ 10-2 mg/L. Based on the results of risk assessment, it is very important for the decision makers to incorporate remedial activities including institutional controls, engineering controls, and remediation programs from RBCA results. This study provides a streamlined process and guidelines of developing the risk-based decision-making strategy for contaminated sites in Taiwan.
402

The relationship between sensitivity to criticism and cognitive distortions in women suffering from bulimia

Demos, Stacy A. January 2000 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 51-58). Also available on the Internet.
403

Modification of the infant contrast sensitivity card procedure /

Drover, James R., January 2000 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Bibliography: leaves 45-57.
404

The relation of anxiety sensitivity and coping strategy to carbon dioxide-induced anxious and fearful responding

Spira, Adam P. January 2001 (has links)
Thesis (M.A.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains v, 51 p. Includes abstract. Includes bibliographical references (p. 37-41).
405

Pay-performance sensitivity during financial distress : Did the financial crisis change payperformance sensitivity?

Nellkrans, Gabriel, Dogan, Seyfi January 2015 (has links)
This study examines the existence of pay-performance sensitivity in total compensation and bonus during the financial crisis, using data between 2007-2010 from Swedish 196 listed firms. We perform panel data regression analysis of CEO compensation on financial performance measured as stock returns. Our results indicate that there is, although not significant, a weak positive relationship between CEO compensation and firm performance during 2007-2010. However during 2009-2010 in a market state defined as post-crisis we find weak negative pay-performance sensitivity at a significance level of 10 %. Nevertheless, as regards to the bonus paid to executives there was a significantly positive relationship relative bonus % and firm performance. These results contribute to our understanding of the pay-performance sensitivity in times of financial disturbance, highly relevant to the existing debate considering CEO compensation.
406

Structure and Function of Pinniped Vibrissae

Murphy, Christin Taylor 01 January 2013 (has links)
The vibrissal system of pinnipeds relies on sturdy, specialized vibrissae and supporting neural architecture apparently designed for the reception of waterborne disturbances. Although it is known that pinnipeds can use their vibrissae for fine-scale tactile discrimination and hydrodynamic detection, many aspects of vibrissal function remain poorly understood. The present work examined the adaptive significance of vibrissal structure, the sensitivity of the vibrissal system, and the signals received by this system. All of these points were considered with respect to their function in hydrodynamic reception. Four methods of study: laser vibrometry, computed tomography (CT) scanning, psychophysical testing and animal-borne tagging were used to investigate the functioning of this sensory system. Laser vibrometer recordings were used to investigate the effect of vibrissal surface structure and orientation on flow-induced vibrations in excised vibrissae. Vibrations were recorded from the shaft of excised vibrissae exposed to laminar water flow in a flume tank. Samples from three pinniped species were tested: the harbor seal (Phoca vitulina), northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus). The vibrissae of the seals had an undulated surface structure, while the vibrissae of the sea lion had a smooth surface. No significant difference between species, and therefore surface structure, was observed. However, when vibrissae were tested at three angles of orientation to the water flow, a strong effect of orientation on vibration frequency and velocity was observed across species. CT scanning data revealed that the vibrissae of all the species tested had flattened cross-sectional profiles. This cross-sectional flattening could account for the observed orientation effects. Furthermore, this morphological characteristic may represent an adaptation for improved functioning in the aquatic environment by reducing self-induced-noise from swimming and potentially enhancing detection of signals from other planes. Psychophysical testing was conducted with a trained harbor seal in order to investigate the sensitivity of the vibrissal system of this species. A behavioral procedure was used to measure absolute detection thresholds for sinusoidal stimuli delivered to the vibrissae by a vibrating plate. Thresholds were measured at 9 discrete frequencies from 10 to 1000 Hz. The seal's performance in this stimulus detection task showed that the vibrissal array was sensitive to directly coupled vibrations across the range of frequencies tested, with best sensitivity of 0.09 mm/s at 80 Hz. The velocity thresholds as a function of frequency showed a characteristic U-shaped curve with a gradual low-frequency roll-off below 80 Hz and a steeper high-frequency roll-off above 250 Hz. The thresholds measured for the harbor seal in this study were about 100 times more sensitive than previous in-air measures of vibrissal sensitivity for this species. The results were similar to those reported by others for the detection of waterborne vibrations, but show an extended range of frequency sensitivity. Animal-borne tagging methods were used to investigate the signals received by the vibrissae and better understand the relevant signal components involved in hydrodynamic detection. A novel tagging system, wLogger, was developed to record vibrations directly from a vibrissa by means of an accelerometer coupled to the vibrissal shaft. Laboratory testing using excised whiskers in a water flume confirmed that the tag is capable of recording vibrational signals without hampering the natural movement of the vibrissa. In addition, the tag successfully measured vibrations from the vibrissae of a harbor seal during active swimming and hydrodynamic detection. Live animal testing, along with the supplemental recordings from excised vibrissae, revealed that interaction with hydrodynamic disturbances disrupted the vibrational signal received by the whisker. When exposed to a hydrodynamic signal, whisker vibrations increased in bandwidth, spreading energy across a wider range of frequencies. This finding suggests that modulation of the vibrational signal may play a key role in the detection of hydrodynamic stimuli by the seal. The results of this dissertation research provide insight into the functioning of the vibrissal system in pinnipeds and establishes the groundwork for future pathways of investigation. By investigating the vibrissal system from the focal points of structure, sensitivity and received signals, a more comprehensive understanding of this refined sensory modality is emerging.
407

Who am I and where do I belong? Cultural identity conflict, negotiation and intercultural competence among Chinese international students

Yu, Yiting January 2015 (has links)
In order to improve international student enrolment, universities have to tackle challenges of ensuring satisfying experience of enrolled international students that is perceived to greatly impact future recruitment. Accordingly, this research aims to provide valuable insights into Chinese international students’ cultural identity conflict that hinders their obtainment of a positive overseas experience. An online survey assessing a range of predictors of cultural identity conflict involving personality traits, ethnic and host cultural identity strength, intergroup factors and strategies of negotiating ethnic and host cultures, and how identity conflict and various identity negotiation strategies influence intercultural competence, was distributed to the entire pool of Chinese students enrolled in a New Zealand university and an Australian university. A total of 255 students completed the survey. Multiple regression analysis revealed that conscientiousness, secure attachment, commitment to ethnic identity, low perceived discrimination, easy access to academic activities with host students significantly protected Chinese students from experiencing cultural identity conflict, whereas preoccupied and fearful attachment, assimilation strategy increased the risk of identity conflict. Additionally, Alternation between cultural demands as one of variations of integration strategy was surprisingly found to exacerbate identity conflict and led to lower levels of intercultural sensitivity, while the other variation, blending strategy significantly resulted in greater intercultural sensitivity. Managerial implications for educational institutions were discussed based on these results. To advance this field of study, limitations of the current research and future research avenues were also presented.
408

The effects of prolonged sitting and acute exercise on postprandial plasma triglyceride concentration

Kim, Il-Young, 1973- 31 January 2012 (has links)
These studies investigated the effect of physical inactivity (prolonged sitting) and physical activity (walking, standing, and moderate intensity exercise) on postprandial plasma triglyceride concentration (PPTG). In the first study, we evaluated the effect of low intensity intermittent walking at ~25% VO₂max (WALK) and energy-matched moderate intensity running at ~65% VO₂max (RUN) on PPTG, compared to a sitting control (SIT). RUN reduced incremental area under the curves for plasma triglyceride concentration (TG AUC[subscript I]), compared to WALK by 17.3% (p = 0.04) and SIT by 27% (p [less than] 0.001). The reduced TG AUC[subscript I] in RUN was accompanied by enhanced whole body insulin sensitivity, compared to WALK and SIT (for both, p [less than] 0.05). Whole body postprandial fat oxidation at rest following a high fat test meal intake was enhanced in RUN by 31% (P [less than] 0.001) and to a lesser extent in WALK by 8.4% (p [less than] 0.005), compared to SIT. In the second study, we evaluated 1) the effect of 2 days of prolonged sitting on PPTG, and 2) the effect of 4 days of SIT on the ability of an acute bout of exercise to reduce PPTG, compared to the same days of active walking and standing with calorically balanced diet (WALK+B). To distinguish the effect of prolonged sitting from the excess calorie effect, we had a sitting condition with calorically balanced diet (SIT+B) in addition to a sitting condition with hypercaloric diet (SIT+H). Following 2 days of respective food and activity control, WALK+B was lower in TG AUC[subscript T] by 21.3% and AUC[subscript I] by 17.4%, compared to SIT+H (for both, p [less than] 0.005). WALK+B was lower than SIT+B for TG AUC[subscript T] by 17.7% (p = 0.165) and AUC[subscript I] by 23.5% (p = 0.145) although statistical significance was not achieved. Remarkably, an acute exercise following 4 days of either SIT+H or SIT+B failed to reduce both TG AUC[subscript T] and AUC[subscript I], compared to SIT+B in HFTT1. The same exercise following 4 days of WALK+B, however, reduced both TG AUC[subscript T] by 29% and TG AUC[subscript I] by 32% in HFTT2, compared to SIT+B in HFTT1 (for both, p [less than] 0.02). Further, both SIT conditions reduced relative whole body fat oxidation in favor of increases in carbohydrate oxidation, compared to WALK+B by more than 40% in both HFTT1 and HFTT2. Taken together, our data suggest that 1) exercise intensity plays an independent role with higher intensity being more effective than lower intensity exercise in reducing PPTG, and 2) prolonged sitting with excess energy intake amplifies PPTG and prolonged sitting impairs the ability of an acute bout of moderate intensity exercise to reduce PPTG. This emphasizes the importance of regular participation in moderate-to-vigorous intensity exercise and reducing sitting time by increasing non-exercise physical activities (i.e., walking and standing) for the favorable postprandial metabolic health from the individual and public health perspectives. / text
409

Generation of high fidelity covariance data sets for the natural molybdenum isotopes including a series of molybdenum sensitive critical experiment designs

Van der Hoeven, Christopher Ainslie 15 October 2013 (has links)
Quantification of uncertainty in computational models of nuclear systems is required for assessing margins of safety for both design and operation of those systems. The largest source of uncertainty in computational models of nuclear systems derives from the nuclear cross section data used for modeling. There are two parts to cross section uncertainty data: the relative uncertainty in the cross section at a particular energy, and how that uncertainty is correlated with the uncertainty at all other energies. This cross section uncertainty and uncertainty correlation is compiled as covariance data. High fidelity covariance data exists for a few key isotopes, however the covariance data available for many structural materials is considered low fidelity, and is derived primarily from integral measurements with little meaningful correlation between energy regions. Low fidelity covariance data is acceptable for materials to which the operating characteristics of the modeled nuclear system are insensitive. However, in some cases, nuclear systems can be sensitive to isotopes with only low fidelity covariance data. Such is the case for the new U(19.5%)-10Moly foil fuel form to be produced at the Y-12 National Security Complex for use in research and test reactors. This fuel is ten weight percent molybdenum, the isotopes of which have only low fidelity covariance data. Improvements to the molybdenum isotope covariance data would benefit the modeling of systems using the new fuel form. This dissertation provides a framework for deriving high fidelity molybdenum isotope covariance data from a set of elemental molybdenum experimental cross section results. Additionally, a series of critical experiments featuring the new Y-12 fuel form was designed to address deficiencies in the critical experiment library with respect to molybdenum isotopes. Along with existing molybdenum sensitive critical experiments, these proposed experiments were used as a basis to compare the performance of the new high fidelity molybdenum covariance data set with the existing low fidelity covariance data set using the nuclear modeling code SCALE. The use of the high fidelity covariance data was found to result in reduced overall bias, reduced bias due to the molybdenum isotopes, and improved goodness-of-fit of computational results to experimental results. / text
410

Parametric uncertainty and sensitivity methods for reacting flows

Braman, Kalen Elvin 09 July 2014 (has links)
A Bayesian framework for quantification of uncertainties has been used to quantify the uncertainty introduced by chemistry models. This framework adopts a probabilistic view to describe the state of knowledge of the chemistry model parameters and simulation results. Given experimental data, this method updates the model parameters' values and uncertainties and propagates that parametric uncertainty into simulations. This study focuses on syngas, a combination in various ratios of H2 and CO, which is the product of coal gasification. Coal gasification promises to reduce emissions by replacing the burning of coal with the less polluting burning of syngas. Despite the simplicity of syngas chemistry models, they nonetheless fail to accurately predict burning rates at high pressure. Three syngas models have been calibrated using laminar flame speed measurements. After calibration the resulting uncertainty in the parameters is propagated forward into the simulation of laminar flame speeds. The model evidence is then used to compare candidate models. Sensitivity studies, in addition to Bayesian methods, can be used to assess chemistry models. Sensitivity studies provide a measure of how responsive target quantities of interest (QoIs) are to changes in the parameters. The adjoint equations have been derived for laminar, incompressible, variable density reacting flow and applied to hydrogen flame simulations. From the adjoint solution, the sensitivity of the QoI to the chemistry model parameters has been calculated. The results indicate the most sensitive parameters for flame tip temperature and NOx emission. Such information can be used in the development of new experiments by pointing out which are the critical chemistry model parameters. Finally, a broader goal for chemistry model development is set through the adjoint methodology. A new quantity, termed field sensitivity, is introduced to guide chemistry model development. Field sensitivity describes how information of perturbations in flowfields propagates to specified QoIs. The field sensitivity, mathematically shown as equivalent to finding the adjoint of the primal governing equations, is obtained for laminar hydrogen flame simulations using three different chemistry models. Results show that even when the primal solution is sufficiently close for the three mechanisms, the field sensitivity can vary. / text

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