Physical Sciences and Mathematics Commons^™

Goal-Oriented Job Scheduling For Parallel Computer Systems, Sangsuree Vasupongayya

Dissertations and Theses

System administrators for parallel computers face many difficulties when managing job scheduling systems. First, current production job schedulers use many parameters, which seem flexible but it is highly challenging to configure and tune these parameters. Second, fair share is an important scheduling goal, but it is not clear what kind of fair share can be expected under current schedulers and how fair share impacts scheduling performance. Third, several job runtime prediction methods were proposed to improve inaccurate user-estimated runtimes, but these methods could under-estimate runtimes by a large amount and it is not clear whether they are practical for use …

The Characterization Of Trna Modifying Enzymes S-Adenosylmethionine : Trna Ribosyltransferase-Isomerase (Quea) And A Novel Type I Gtp Cyclohydrolase, Shilah Amal Bonnett

Dissertations and Theses

Queuosine is a hypermodified nucleoside located in the wobble position of bacterial and eukaryotic tRNAs coding for Asp, Tyr, His and Asn. The biosynthesis involves the participation of S-adenosyl-methionine:tRNA ribosyltransferase-isomerase (QueA) and a GTP Cyclohydrolase-I. QueA catalyzes the transfer and isomerization of the ribosyl moiety from AdoMet to preQ1 modified tRNA. Substrate analogs of AdoMet were used to elucidate important substrate-enzyme interactions and to test key steps in the proposed chemical mechanism. Replacing AdoMet with SeAdoMet had little effect upon substrate binding but exhibited 30-fold reduction in kcat, consistent with deprotonation at C-5' as the first catalytic step. 7-deazaAdoMet failed …

Biosedimentology Of Thermal Features In The Uzon Caldera, Kamchatka, Russia : Implications For Biosignature Formation, Jessica Christine Goin

Dissertations and Theses

Modern hot springs serve as a habitat for microorganisms similar in metabolism, morphology, and cellular structure to the microbes that existed relatively early in Earth history. To maximize our ability to interpret evidence for these microorganisms and their communities in the rock record, we need to understand how their biosignatures form and become preserved.

This biosedimentological study of four thermal features in the Uzon Caldera (K4 Well, Ochki Pool, Thermophile Spring, and Zavarzin Pool) focused on identifying how chemical, physical and biological inputs contribute to the characteristics of sinter biofabrics. The biofabrics of K4 Well outflow channel were studied in …

Graduate Teaching Assistants' Statistical Knowledge For Teaching, Jennifer Ann Noll

Dissertations and Theses

This dissertation explores graduate teaching assistants’ (TAs’) statistical knowledge for teaching. Data collection methods that enabled the exploration of TA s’ statistical knowledge for teaching include: (a) a task-based web survey administered to 68 TAs from 18 universities across the United States; and, (b) a series of three taskbased interviews with a subset of five TAs from the larger survey population. Through and Strauss, 1967), I investigated the ways in which TAs reason about sampling tasks, and how they think about teaching and student learning in relation to sampling ideas. Building on past research in statistics education on K-12 and …

A Qualitative Analysis Of Hybrid Control Systems, Anca Georgeta Williams

Dissertations and Theses

Hybrid Control Systems are increasingly investigated as models for control systems where the interaction between continuous and discrete processes is tightly integrated. As yet, there is no general agreement as to what constitutes a canonical hybrid system. Rather various subclasses of systems combining continuous evolution and discrete event characteristics are analyzed for each application. In this dissertation we first unify the presentation of hybrid systems with a rich model which encompasses most examples of interest. We classify the available results and show how they fit together within the different subcategories. In the main part of the dissertation we prove that …

The Effects Of Coypu Myocaster Coypus (Nutria) Trapping On The Water Quality Of South Johnson Creek, Beaverton, Oregon, Deborah Jean Frankel

Dissertations and Theses

Nutria are semi-aquatic rodents, non-native to Oregon. They are an invasive species that damage stream banks with burrowing and cause destruction of native vegetation; activity that may cause deterioration of stream water quality. I hypothesized that my study's duration and pattern of nutria trapping along South Johnson Creek would be sufficient to lead to a significant change in turbidity, dissolved oxygen (DO), total dissolved solids (TDS), total solids (TS), and total suspended solids (TSS).

Microbial Biosignatures In High-Iron Thermal Springs, Mary Nichole Parenteau

Dissertations and Theses

Debate exists regarding whether abiotic or biotic mechanisms were responsible for the oxidation of Fe²+ and the subsequent accumulation of ferric (Fe³+) iron assemblages in Precambrian Banded Iron Formations (BIFs). Direct paleontological evidence for a microbial role in the deposition of BIFs has been sought in the occurrence of microfossils and lipid biomarkers in these structures.

This study has characterized the formation of such biosignatures in modern iron deposits. The metabolic impact of microbes on Fe2+ oxidation in this system has previously been described (Pierson et al., 1999; Pierson and Parenteau, 2000). Cyanobacterial and filamentous anoxygenic …

Thin Film Solar Cells Using Zno Nanowires, Organic Semiconductors And Quantum Dots, Kaitlyn Vansant

Dissertations and Theses

A thin film organic/ inorganic hybrid solar cell was fabricated by incorporating ZnO nanowires, n- and p-type organic semiconductors and inorganic quantum dots. The basic cell design involved the electrodeposition of ZnO nanowires grown on a substrate coated with a transparent conductive oxide. The ZnO nanowires were coated with a thin layer of an organic n-type material, followed by a deposition of inorganic quantum dots. A p-type polymer layer was subsequently deposited and the sample was then contacted with gold to form a quantum dot layer sandwiched between a p-n junction of organic conductive materials.

Various materials and processing methods …

Selected Chemistry Of Biologically-Active Thiols : N-Acetylpenicillamine And 2-Mercaptobenzothiazole In Nitrosothiol Formation And Role In Allergic Contact Dermatitis Respectively, Itai Chipinda

Dissertations and Theses

Two biologically-active thiols, N-acetylpenicillamine (NAP) and 2-mercaptobenzothiazole (MBT), were studied in this thesis. NAP is known to combine with nitric oxide (NO) to produce S-nitroso-N-acetylpenicillamine (SNAP) and MBT is a known allergen.

The formation, reaction dynamics, and detailed kinetics and mechanism of the reaction between nitrous acid (HNO2), prepared in situ, and NAP to produce SNAP were studied. The reaction is first order in nitrite, NAP and acid in pH conditions at or slightly higher than the pKa of HNO2. Both HPLC and quadrupole time-of-flight mass spectrometry techniques confirmed the formation of SNAP and the absence of any other products. …

Seasonal Changes In Allocation, Growth, And Photosynthetic Responses Of The Submersed Macrophyte Egeria Densa Planch. (Hydrocharitaceae) From Oregon And California, Toni Garrett Pennington

Dissertations and Theses

Many rooted macrophytes form a dense canopy on the water surface that is detrimental to aquatic organisms, water quality, navigation, and recreation. Control of invasive macrophytes may be improved when management activities are linked to the plant's biology. The purpose of this research was to evaluate seasonal changes in the morphology, growth rates, allocation patterns and photosynthetic responses of a clonal submersed macrophyte. Egeria densa Planch. (Hydrocharitaceae) is highly invasive in the USA where it forms dense surface canopies in freshwater ecosystems. Using E. densa the following hypotheses were evaluated: (1) flowering stems have reduced capacity for vegetative growth as …

Using Building Energy Simulation And Geospatial Modeling Techniques In Determine High Resolution Building Sector Energy Consumption Profiles, Shem C. Heiple

Dissertations and Theses

A technique is presented for estimating hourly and seasonal energy consumption profiles in the building sector at spatial scales down to the individual taxlot or parcel. The method combines annual building energy simulations for cityspecific prototypical buildings and commonly available geospatial data in a Geographical Information System (GIS) framework. Hourly results can be extracted for any day and exported as a raster output at spatial scales as fine as an individual parcel (