Physical Sciences and Mathematics Commons^™

Photoadaptation Rate Of Synechococcus Wh7803 Cultures At Two Iron Concentrations, Jon Daniel Moulton

Dissertations and Theses

The marine cyanobacterium Synechococcus WH7803 adapts to changes in light intensity by changing its photosynthetic physiology. This work is a study o f the rate o f photoadaptation of Synechococcus WH7803 in laboratory cultures. Cultures were shifted from constant 8 µEm^-2s^-1 light to constant 80 µEm^-2s^-1 light, from constant 80 µEm^-2s^-1 light to 8 µEm^-2s^-1 light and from different light regimes to a single fluctuating light regime. The response of high iron cultures grown in modified aquil culture medium at 5*10^-6M Fe was compared with the …

Spectroscopy Of Charge-Coupled Devices, Lars Mündermann

Dissertations and Theses

A systematic study of persistent, or residual, images occurring in CCD imagers and a systematic study of dark current generation in CCD imagers are presented. These effects are a source of unwanted signal in frames, and should be considered where very exact, low light-level signal processing is necessary. For both studies explanatory models and statistical analysis techniques have been developed which enable the derivation of the densities and the characteristic energies. Furthermore the importance of understanding these phenomena in the context of today's low light-level imaging is discussed.

Impurity sites are found to be responsible for residual images. Photoelectrons are …

Specification-Driven Optimization, Sheena Day

Dissertations and Theses

Traditionally, optimizing transformations have been built into compilers. The end-user has little or no control over guiding any optimizations that may be applied by the compiler. Moreover, the compiler-writer does not have a simple way to direct the optimizations. Thus, many potentially beneficial opportunities for code optimization may be lost. We have built a system that allows the user to participate in guiding source-to-source transformations via the specification of rewrite rules. A clean separation of the rules from the strategy of applying them makes the system easier to use and modify, compared to other integrated systems. This is especially relevant …

The Green Dyadic Formulation For Radiation Problems With Arbitrary Sources Embedded In Stratified Multi-Layer Structures : Application To Molecular Fluorescence Problems, Robert Lyle Hartman

Dissertations and Theses

The Green Dyadic method for computing fields due to current sources between parallel interfaces of dielectric materials is studied. Computer implementation of the method as presented in a well-known article leads to the conclusion that significant errors are present. Two dissimilar methods of solution lead to corrected formulations which are shown to be equivalent. The same correction is found in the research literature. For confirmation, computations are performed in examples involving an emitting dipole by both the Green dyadic method and Sommerfeld' s Hertz vector method. Finally, the computational examples are used to compute fluorescence decay rates for emitting dipoles …

High Resolution Seismic Reflection Interpretations Of The Hood Canal-Discovery Bay Fault Zone, Puget Sound, Washington, Brian J. Haug

Dissertations and Theses

The north-northeast trending Hood Canal is an elongate 75 km long, 2-5 km wide, maximum 190 m deep glacial trough that represents the western limit of Washington's Puget Sound estuary complex and eastern boundary of the Olympic Peninsula. Airgun seismic reflection data were collected in Hood Canal April 4-5, 1994 onboard the University of Washington's R. V. Thomas G. Thompson for the purpose of defining the enigmatic and relatively unstudied Hood Canal-Discovery Bay fault zone (HDF). This fault zone parallels western Hood Canal, is obscured by marine waters and thick late Quaternary glacio-marine sediments, and is defined locally by gravity …

Usability Of Visual Basic For Parallel Programming On Windows Nt, James Scott Barker

Dissertations and Theses

Visual Basic is a very popular language. Many hardware engineers have learned Visual Basic because of its simplicity, but have never learned C or C++. Furthermore, people are choosing not to use C or C++ for business software development, but instead are embracing languages such as Visual Basic. Since one of the goals of the parallel programming community has been to encourage more widespread use of parallelism in software, this body of programming talent needs to be addressed. This thesis intends to prove that Visual Basic can be used for parallel programming, that using it is at least as easy …

Paramagnetic Nuclear Magnetic Resonance (Nmr) Studies On The Calcium Binding Site Of [Alpha]-Lactalbumin, Thomas Kurt Ritter

Dissertations and Theses

Paramagnetic NMR has drawn interest as a technique for extending the range of systems that can be investigated. The purpose of this study was to determine whether a combination of paramagnetic two-dimensional and relaxation techniques allows for assigning resonances corresponding to residues forming the metal binding site of proteins in which the metal is coordinated exclusively by amino acid side chains and which have been previously inaccessible to assignment.

α-Lactalbumin (LA) is a calcium binding protein with relatively broad NMR signals; this broadness has prevented complete assignment. LA has been the subject of many studies, because it can form a …

The Synthesis And Characterization Of A Porphyrin Oligomer As A Potential Antenna For Light Harvesting Solar Cells, Tristan Timothy Jenkins

Dissertations and Theses

Mankind's attempts to harvest the sun have resulted in photocells with about 15% overall energy conversion efficiency. The best of these cells consist of a light-sensitive dye attached to a semiconductor. Absorbed light energy is transferred to the semiconductor via the delivery of an excited electron from the dye. Dye electrons are replenished with a redox solution, coupling the dye to the counter electrode.

This research was the beginning of an exploration into some potential improvements in the cell. First of all, the redox solution is a corrosive liquid, and leaks present a problem. A porphyrin oligomer with a TCPP …

Xanthones As Antimalarial Agents : Binding Interactions Between Heme Analogues And Xanthones, Jane Xu Kelly

Dissertations and Theses

Human falciparum malaria is caused by Plasmodium falciparum parasite, which digests host hemoglobin within its food vacuole, releasing toxic heme. P. falciparum detoxifies free heme to hemozoin by polymerization. This process is believed to be the target of most successful antimalarial drugs, chloroquine and quinine, which are now losing their effectiveness due to the spread of multi-drug resistant strains. Xanthones were recognized in the laboratory of Dr. M. Riscoe (Portland VA Medical Center) to bind to heme, preventing heme polymerization [Ignatushchenko, M., Winter R., and Riscoe, M. (1997) FEBS Letters 409, 67].

This thesis reports a study of the interactions …