Although much progress has been made in the United States, childhood lead poisoning remains a critical environmental health problem. Lead causes many problems such as learning disabilities, coma, and even death. Many studies have focused on these problems in the last three decades, but Geographic Information System (GIS) technology has only been employed since the 1990s. In addition, no research has examined the differences among the models based on the different geographic locations and size of cities. In this study, screening results of childhood lead levels in Indiana are evaluated based on a census tract geography. The relationship between the number of children less than six years old with elevated Blood Lead Levels (BLLs) and social-economic factors such as percentage of children in poverty and age of housing stock are examined for selected urban areas in Indiana. Stepwise and backward elimination are used to choose the independent variables and least squares regression methods are used to build evaluation models according to the location and size of urban areas in Indiana. Finally, a comparison is made among these models to examine whether there is any difference according to city size and location, and whether a state level model would be suitable for the selected urban areas. The results show that backward elimination is a better way to select the independent variables in most of the models. The census tracts with high value of residuals are located in the outer periphery of most urban areas. For some models, the residuals are lower in the census tracts with a high ratio of children screened. The results also manifest that some of the same parameters exist in the models of the same urban size or location in Indiana and geographic factors could be potential elements in building model for children’s EBLLs. None of the models have exactly the same parameters. In addition, the comparison shows that the state model is not as accurate as the urban area models. How to balance the weakness of both state model and urban area model could be an extension for further study. / Department of Geography

Graduation date: 1993

This thesis investigates the use of single Cooper-pair transistor (SCPT) for fast and sensitive detection of quasiparticle dynamics. This investigation is motivated by the possibility of quantum information processing using superconducting nanoscale circuits, such as the SCPT and the Cooper-pair-box (CPB). In the SCPT coherent charge transport can be temporarily halted due to quasiparticle tunnelling, known as quasiparticle poisoning. Quasiparticle poisoning can be reduced by the use of engineered island and lead gap energies. The thesis begins by reporting measurements of the superconducting gap in aluminium - aluminium-oxide - aluminium tunnel junctions, as a function of film thickness. We have observed an increase in the superconducting energy gap of aluminium with decreasing film thickness. This method is used to engineer the island and gap energies in a SCPT and consequently we observe reduced poisoning and a modification of the thresholds for finite bias transport processes. Radio-frequency reflectometry is used to perform high-bandwidth measurements of quasiparticle tunnelling in a gap engineered SCPT. A model for the radio-frequency (rf) operation of the SCPT is presented and shows close agreement with experiment. Thermal activation of the quasiparticle dynamics is investigated, and consequently, we are able to determine energetics of the poisoning and unpoisoning processes. This enables an effective quasiparticle temperature to be determined, allowing the poisoning to be parametrised. An investigation of the use of normal metal quasiparticle traps for suppression of quasiparticle poisoning in SCPT devices is performed. To date, there has been little quantitative information about the behaviour of quasiparticle traps even though they have been used extensively. The work presented serves to clarify the nature of quasiparticle trap performance. Finally the single-quasiparticle sensitivity of the SCPT is employed to directly probe a few quasiparticle gas in a small superconducting volume. The quasiparticle population is monitored both in the steady-state and under non-equilibrium conditions of injection. In the non-equilibrium regime the quasiparticle recombination time is accessed from the response of the SCPT to pulsed injection. Agreement to previous experimental studies of recombination times in aluminium is found.

Thesis (PhD (Paraclinical Sciences))--University of Pretoria, 2006. / Includes bibliographical references.

Thesis (M.Sc.)--Victoria University of Wellington, 2008. / Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Dept. of Anthropology, 2007. / Includes bibliographical references.

Thesis (Ph.D.) -- University of Rhode Island, 2008. / Typescript. Includes bibliographical references (leaves 141-159).

Mémoire (M.Ress.Renouv.)-- Université du Québec à Chicoutimi, 1993. / Document électronique également accessible en format PDF. CaQCU

Thesis (Ph.D.)--The Ohio State University, 2007. / Adviser: Timothy Haab. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1995. / Added t.p. with thesis statement inserted.