The regulation of monooxygenase enzymes has been demonstrated in bacteria that grow on methane and long chain-length alkanes (>C10). Less is known about monooxygenase regulation in short chain alkane oxidizing bacteria that grow on intermediate chain-length alkanes C2-C10. This dissertation focuses on the regulation of butane monooxygenase (BMO) expression and...
This dissertation uses argon geochronology and cosmogenic nuclide surface exposure dating methods to address three research questions. The first question concerns a geomagnetic instability recorded in lava flows on the island of Floreana in the Galapagos Archipelago. Changes in the Earth’s magnetic field (intensity and orientation) occur frequently throughout geologic...
This dissertation presents the results of statistical analyses of large climate datasets from two time intervals – the 20th century instrumental record and the proxy record of the last deglaciation – in order to understand the forcings and mechanisms of past climate variability.
A longstanding question in climate dynamics concerns...
The tosylhydrazones of 2-heptanone, 4,4-dimethy1-2-
heptanone, 6-heptyn-2-one and 4,4-dimethy1-6-heptyn-2-
one were synthesized and decomposed under a variety of
reaction conditions: dry lithium and sodium salt pyrolyses,
sodium methoxide thermolyses in diglyme and photolyses of
the lithium salt in tetrahydrofuran. The saturated analogues
2-heptanone tosylhydrazone and its 4,4-dimethyl
isomer afforded the...
The purpose of this work is to broaden the theoretical foundations of interpolation of spatial data, by showing how ideas and methods from information theory and signal processing are applicable to the the work of geographers. Attention is drawn to the distinction between what we study and how we represent...
The cause of warming in the Southern Hemisphere during the most recent deglaciation remains a matter of debate[superscript 1,2]. Hypotheses for a Northern Hemisphere trigger, through oceanic redistributions of heat, are based in part on the abrupt onset of warming seen in East Antarctic ice cores and dated to 18,000...
Mycobacterium avium is a ubiquitous environmental organism found in both water and soil. It can cause disease in patients with previous pulmonary conditions, as well as immunosupressed patients, with the most prevalent being AIDS patients. Studies have indicated that passage through amoeba, a common environmental protozoa, increases virulence of M....
Methane is a product of biogeochemical processes which respond to changes in climate. The history of atmospheric methane is recorded by ice cores providing insight into past changes in these biogeochemical processes. This dissertation is comprised of three studies which focus on centennial- and millenial-scale variability of methane from ice...
Atmospheric carbon dioxide levels have been steadily increasing from anthropogenic energy production, development and use. Carbon cycling in the terrestrial biosphere, particularly forest ecosystems, has an important role in regulating atmospheric concentrations of carbon dioxide. US West coast forest management policies are being developed to implement forest bioenergy production while...