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Laboratory study evaluating electrical resistance heating of pooled trichloroethyleneMartin, Eric John 18 March 2009 (has links)
A laboratory scale study was conducted to evaluate the thermal remediation of trichloroethylene (TCE) in a saturated groundwater system using electrical resistance heating (ERH). Two experiments were conducted using a two-dimensional polycarbonate test cell, the first consisting of a single pool of TCE perched above a capillary barrier, the second consisting of two pools of TCE each perched on separate capillary barriers. Temperature data was collected during the heating process from an array of 32 thermocouples located throughout the test cell. Visualization of the vaporization of liquid phase TCE, as well as the upward migration of the produced vapour was recorded using a digital camera. Chemical testing was performed 48 hours after experiment termination to measure post heating soil concentrations. A co-boiling plateau in temperature was found to be a clear and evident earmark of an ongoing phase change in the pooled TCE. Temperature was found to increase more rapidly in the second experiment that included a fully spanning barrier. As temperatures increased above the co-boiling plateau, vapour rise originating from the source zone was observed, and was found to create a high saturation gas zone beneath the upper capillary barrier when no clear pathway was available for it to escape upwards. When the source zones had reached the target temperature of 100°C and the ERH process stopped, this high saturation gas zone condensed, leading to elevated TCE concentrations below as well as within the capillary barrier itself. The water table within the experimental cell was also noted to drop measurably when the gas zone collapsed. Post-testing chemical analysis showed reductions in TCE concentrations of over 99.04% compared to the source zone, although due to condensation of entrapped gas and convective mixing, there was a net redistribution of TCE within the experimental domain, especially within confined areas below the capillary barriers.
A secondary set of experiments were conducted using a homogenous silica sand pack with no chemical contaminants to determine the effect, if any, of the wave shape of electrical input on the ERH process. It was found that in early time heating, square wave inputs consistently produced a more localized heating pattern when compared to the standard sine wave electrical input. This effect equalized between the two experiments as the ERH process went on, perhaps due to the increased dominance of conduction and convection as the mode of heat transfer in the test cell at higher temperatures. It is believed that the localization of heating in square wave experiments is due to a consistent power supply due to the lack of a sinusoidal ramping in power delivery. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-03-18 14:40:46.019
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Analysis of States Gun Control RestrictionsCheng, Xiaofeng 28 June 2002 (has links)
This thesis analyzes the policy effects of several state gun control restrictions in the United States. The study employs the data of gun related crimes and gun control restrictions from Statistical Abstract of Criminal Justice Handbook through five years (from 1995 to 2000). Although many scholars have studied previously gun control policy effects on crimes, they always focus on the total violence level and ignore to compare the policy effects of different gun control laws. The present study examines intensively gun related crimes and compares several gun control policies.
Pooled data is employed to access the effects of gun control restrictions, and it is another advancement based on previous studies, which always use cross-sectional or time series designs. These findings partially reject the previous conclusions that gun control laws have no effects on violence and for gun related homicides and robberies; several gun control restrictions like registration, license, and waiting period show some significant policy effects. Contrary to the past study, the permit to purchase, which has been regarded as the most efficient law, produces no significant policy effects. Sale report to police and certain firearm prohibited also have no significant effects. Among control variables, race and urban population exert the obvious influences on the gun violence, and specifically, the density of population affects the gun related homicides and high school graduates affects the gun related robberies. Implications of these findings and potential for future research are discussed.
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Essays on financial development and economic growthSamargandi, Nahla January 2015 (has links)
This thesis is based on three empirical essays in financial development and economic growth. The first essay, investigated in the third chapter, the effect of financial development on economic growth in the context of Saudi Arabia, an oil-rich economy. In doing so, the study distinguishes between the effects of financial development on the oil and non-oil sectors of the economy. The Autoregressive Distributed Lag (ARDL) bounds test methodology is applied to yearly data over the period 1968 to 2010. The finding of this study is that financial development has a positive impact on the growth of the non-oil sector. In contrast, its impact on the oil-sector growth and total GDP growth is either negative or insignificant. This suggests that the relationship between financial development and growth may be fundamentally different in resource-dominated economies. The second essay revisited, in the fourth chapter, the relationship between financial development and economic growth in a panel of 52 middle-income countries over the 1980-2008 period. Using pooled mean group estimations in a dynamic heterogeneous panel setting, we show that there is an inverted U-shaped relationship between finance and growth in the long-run. In the short run, the relationship is insignificant. This suggests that too much finance can exert a negative influence on growth in middle-income countries. The finding of a non-monotonic effect of financial development on growth is confirmed by estimating a dynamic panel threshold model. The third essay empirically explores cross-country evidence of the effects of financial development shocks on economic growth. It employs a Global Vector Autoregressive (GVAR) model, which allows us to capture the dynamics of this relationship in a multi-country setting, and connects countries through bilateral international trade. Given the progressive role that Brazil, Russia, India, China and South Africa (BRICS) play in the world economic arena, this essay focuses on whether financial development in one BRICS member state affects economic growth in the other BRICS. To this end, the study finds empirical evidence that credit to the private sector has a positive spillover effect on growth in some of the BRICS countries. However, the results imply that the current level of financial integration among the BRICS countries is still not mature enough to spur economic growth for all the BRICS members.
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Utilisation des analyses en mélanges pour l'évaluation et le suivi du statut sanitaire des troupeaux : application à la paratuberculose des ovins / Use of pooled sample analysis to evaluate and follow-up flocks sanitary status : application to ovine paratuberculosisMathevon, Yoann 12 April 2018 (has links)
La paratuberculose est une maladie enzootique contagieuse des ruminants due à Mycobacterium avium ssp. paratuberculosis (Map). La longue période d'incubation et les faibles performances diagnostiques des tests limitent l'efficacité des plans de maîtrise. Les grands effectifs des troupeaux ovins limitent l'approche par dépistage individuel exhaustif, et les plans de maîtrise s'orientent vers la vaccination, dont les effets n'ont pas été évalués dans les troupeaux français. Á partir d'échantillons de sérum et de fèces de près de 4000 brebis issues de 30 élevages du Lot, les performances diagnostiques de deux trousses sérologiques ELISA et d'une qPCR sur fèces ont été estimées par des modèles à classes latentes bayésiens et fréquentistes. Nos résultats confirment la faible sensibilité et le défaut de spécificité des sérologies ELISA pour la détection des ovins infectés ; la qPCR présentant de meilleures performances diagnostiques. Par ailleurs nous avons évalué les performances diagnostiques relatives des ELISA et de la qPCR appliquées à des mélanges d'échantillons. Dans les deux cas les animaux forts répondeurs étaient détectés de façon systématique, les animaux faiblement positifs étant détectés de façon moins constante. Sur la base de simulations, nous avons évalué les performances des stratégies de dépistage et de suivi basées sur les analyses de mélanges d'échantillons à l'échelle des troupeaux. Alors que la sérologie ELISA est apparue insuffisamment spécifique, l'analyse de mélange de fèces par qPCR semble être une approche prometteuse, permettant de détecter des faibles prévalences d'infection. Enfin les travaux menés dans les troupeaux vaccinés ont précisé dans quelles mesures leur situation épidémiologique pouvait être approchée par l'emploi d'analyses en mélanges. / Paratuberculosis is a contagious enzootic disease in ruminants caused byMycobacteriumavium ssp. paratuberculosis (Map). The long incubation period and the low informative values of antemortem diagnostic tests limit the effectiveness of control plans. In large sheep flocks, exhaustive individual testing is unfeasible and control plansmainly focus on vaccination, the effects of which have not yet been evaluated in French flocks. Using blood and feces samples from nearly 4000 ewes in 30 sheep flocks from the French department of Lot, the diagnostic performances of two serum ELISA and one fecal qPCR kits were estimated using bayesian and frequentist latent class modeling. Our results confirm the low sensitivity and non-perfect specificity of serum ELISA for the detection of subclinically infected animals, while the diagnostic performances of fecal qPCR were better. We also evaluated the relative diagnostic performances of pooled-sample analysis for both tests. Highly qPCR/ELISA positive samples were invariously detected while low positive ones were associated with lower detection rates. The flock-level epidemiological performances of screening strategies based on pooled-sample analysis were evaluated by simulation studies. Pooled serum ELISA appeared lowly specific. Conversely, pooled fecal qPCR appeared promising, allowing the detection of low infection prevalence. Finally, the work carried out in the vaccinated flocks made it possible to better know their epidemiological status and to specify to what extent it could be approached using pooled-sample analysis.
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Optimizing rare variant association studies in theory and practiceWang, Sophie 06 June 2014 (has links)
Genome-wide association studies (GWAS) have greatly improved our understanding of the genetic basis of complex traits. However, there are two major limitations with GWAS. First, most common variants identified by GWAS individually or in combination explain only a small proportion of heritability. This raises the possibility that additional forms of genetic variation, such as rare variants, could contribute to the missing heritability. The second limitation is that GWAS typically cannot identify which genes are being affected by the associated variants. Examination of rare variants, especially those in coding regions of the genome, can help address these issues. Moreover, several studies have recently identified low-frequency variants at both known and novel loci associated with complex traits, suggesting that functionally significant rare variants exist in the human population.
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The Impact of EU Accession on Trade : The case of Poland, Romania and CroatiaRudelyte, Kotryna, Bertilsson, Maja January 2020 (has links)
One of the main reasons to why a membership in the European Union (EU) is so attractive for prospect countries are the free trade agreements the membership entails. The free trade agreements mean that the whole EU opens up as one big market, where tariffs and tolls are no longer an obstacle to trade for its members. Therefore, this thesis analyses whether EU membership actually yields a positive effect on member’s trade. The time series analysis is based on a three-country sample consisting of Poland, Romania, and Croatia during the time period from 2001 to 2018. By applying multiple and Chow’s breakpoint tests, and country-wise and a pooled cross-section analysis model, we examine if the accession to EU impacts each country’s trade volumes. The results indicate that becoming a member of the European Union does not necessarily have a significant effect on Poland’s, Romania’s, or Croatia’s trade even if it is positive.
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Pennies for Pre-Schoolers: The Role of Foundations in Pre-School Programs, Policies, and ResearchJanuary 2019 (has links)
abstract: The lasting benefits of high-quality early childhood programs are widely understood. These benefits and the well-documented return on investments are among the factors that have shaped executives at philanthropic foundations’ grant making in support of early childhood programs, policies, and research in the United States. Yet little is known about the investments they are making in the field of early childhood. Drawing from a conceptual framework that combines types of philanthropic investment with the concepts of accountability and transparency, I conducted a comparative case study of the Buffett Early Childhood Fund, George Kaiser Family Foundation, and Bill & Melinda Gates Foundation, all of which began financially supporting early childhood between 2000 and 2005. I attempted to understand how and why philanthropic foundations and pooled funding organizations have supported early childhood from the late 1990s through 2018.
Based on my analysis of 32 semi-structured interviews with current and former early childhood philanthropic foundation, pooled funding, and operating organization executives, I found that each foundation independently determines their investment decision processes and invests a disparate amount of money in early childhood. In addition, philanthropic foundations gain programmatic and legislative power by leveraging funds and partnering with additional foundations and businesses. With the inclusion of early childhood programs in K-12 education systems and the decrease in national and state education funding from those same budgets, it is critical to understand how philanthropic foundations have supported early childhood education and some of the implications of their support both locally and nationally. / Dissertation/Thesis / Doctoral Dissertation Educational Policy and Evaluation 2019
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Stock Returns by Sector and Industries in a Year into the COVID-19 PandemicCasas, Simon Alvin A 01 January 2021 (has links)
In the COVID-19 stock market industries reacted and were affected in different ways. This paper will use Standard Industrial Classification (SIC) codes to look at how sectors and selected industries fared after a whole year in a pandemic. This will be accomplished by comparing 2019 stock returns to 2020 stock returns with a t-test and estimating the effect of COVID-19 positive case and death increases using a pooled OLS regression. All SIC sectors A-J were analyzed as well as 18 selected industries such as food stores, real estate, oil and gas extraction, health services, and communications. Results show a significant variation in the monthly returns of 2019 and 2020. Regression results show that there is a small but positive correlation of sector and industry returns to COVID-19 positive case and death increases. This contrary result can confirm the short influential window of COVID-19 outcomes on the stock market as shown in related research. This also confirms that regardless of the continued escalation of the pandemic, the stock market follows sentiment, not substance. This paper will contribute to the existing literature by conducting a yearlong event study of the United States' sectors and industries during the COVID-19 pandemic.
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The Relationship Between Internet Connectivity and Labor Productivity : A study on the correlation between Internet connectivity and labor productivity in the European UnionAgbakwuru, Blaise, Jiang, Ruiyang January 2022 (has links)
The level of labor productivity differs among the European Union countries, especially when you compare a developing country to a more developed country in the EU. This is an issue because the achievement of high labor productivity is a necessary stipulation for a developing economy to realize economic growth and more economic development. On the other hand, the more individuals in an economy with access to the internet (internet connectivity) depicts how developed the economy is in terms of information and communication technology (ICT). Accordingly, the purpose of this paper is to ascertain whether there is a positive relationship between countries having high internet connectivity and labor productivity in the EU. In doing so, Political and entrepreneurial decision-makers can use these findings to decide how much attention or budget to put on the ICT sector to improve labor productivity. To understand the factors that affect labor productivity, Adam Smith and Karl Marx’s theory on labor productivity is used to gain a better understanding. A panel data analysis using a fixed-effect model and pooled OLS regression model is applied in the study to predict the relationship. The result of the study indicates that internet connectivity does not have a significant impact on Labour productivity, or there was not enough evidence showing that they are positively correlated with each other.
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Does Combing Eptifibatide with rt-PA Improve Outcome after Stroke? A Pooled Analysis and Propensity-score Matched AnalysisCornwall, Danielle M. January 2016 (has links)
No description available.
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