Physical Sciences and Mathematics Commons^™

A Model Study Of The Copper River Plume And Its Effects On The Northern Gulf Of Alaska, Yuan Wang

Electronic Theses and Dissertations

Using a three-level nested Regional Ocean Modeling System coupled with the Carbon, Silicate, Nitrogen Ecosystem model, this study examined the seasonal evolution of the Copper River (CR) plume and how it influences the along- and across-shore transport in the northern Gulf of Alaska (NGoA). A passive tracer was introduced in the model to delineate the growth and decay of the plume and to diagnose the spread of the CR discharge in the shelf, into Prince William Sound (PWS) and offshore. Furthermore, a model experiment with doubled discharge was conducted to investigate potential impacts of accelerated glacier melt in future climate …

Developing An Acoustic Method For Reducing North Atlantic Right Whale (Eubalaena Glacialis) Ship Strike Mortality Along The United States Eastern Seaboard, Kaitlyn Allen Mullen

Electronic Theses and Dissertations

North Atlantic right whales (Eubalaena glacialis) are among the world’s most endangered cetaceans. Although protected from commercial whaling since 1949, North Atlantic right whales exhibit little to no population growth. Ship strike mortality is the leading known cause of North Atlantic right whale mortality. North Atlantic right whales exhibit developed auditory systems, and vocalize in the frequency range that dominates ship acoustic signatures. With no behavioral audiogram published, current literature assumes these whales should be able to acoustically detect signals in the same frequencies they vocalize. Recorded ship acoustic signatures occur at intensities that are similar or higher to those …

Identifying Productive Resources In Secondary School Students' Discourse About Energy, Benedikt Walter Harrer

Electronic Theses and Dissertations

A growing program of research in science education acknowledges the beginnings of disciplinary reasoning in students’ ideas and seeks to inform instruction that responds productively to these disciplinary progenitors in the moment to foster their development into sophisticated scientific practice. This dissertation examines secondary school students’ ideas about energy for progenitors of disciplinary knowledge and practice. Previously, researchers argued that students’ ideas about energy were constrained by stable and coherent conceptual structures that conflicted with an assumed unified scientific conception and therefore needed to be replaced. These researchers did not attend to the productive elements in students’ ideas about energy. …

Contextual Analysis Of Large-Scale Biomedical Associations For The Elucidation And Prioritization Of Genes And Their Roles In Complex Disease, Jeremy J. Jay

Electronic Theses and Dissertations

Vast amounts of biomedical associations are easily accessible in public resources, spanning gene-disease associations, tissue-specific gene expression, gene function and pathway annotations, and many other data types. Despite this mass of data, information most relevant to the study of a particular disease remains loosely coupled and difficult to incorporate into ongoing research. Current public databases are difficult to navigate and do not interoperate well due to the plethora of interfaces and varying biomedical concept identifiers used. Because no coherent display of data within a specific problem domain is available, finding the latent relationships associated with a disease of interest is …

Using Hydrologic Measurements To Investigate Free Phase Gas In A Maine Peatland, Usa, Christiaan Bon

Electronic Theses and Dissertations

Northern Peatlands cover more than 350 million ha (~3 percent of Earth’s surface) and are an important source of methane (CH4) and other biogenic gases contributing to climate change. Free phase gas (FPG) accumulation and episodic release has recently been recognized as an important mechanism for biogenic gas flux from peatlands. It is likely that gas production and groundwater flow are interconnected in peatlands: groundwater flow influences gas production by regulating geochemical conditions and nutrient supply available for methanogenesis while FPG influences groundwater flow through a reduction in peat permeability and by creating excess pore fluid pressures. Water samples collected …

Improving The Performance Of The Parallel Ice Sheet Model On A Large-Scale, Distributed Supercomputer, Timothy J. Morey

Electronic Theses and Dissertations

In this thesis, we describe our work to understand and improve the performance and scalability of the Parallel Ice Sheet Model (PISM) on the Ranger supercomputer. PISM enables the simulation of large-scale ice sheets, such as those found in Greenland and Antarctica, which are of particular interest to climate scientists due to their potential to contribute to sea-level rise.

PISM has a unique parallel architecture that is designed to take advantage of the computational resources available on state-of-the-art supercomputers. The problem, however, is that even though PISM can run without modifcation on a supercomputer, it is generally unable to do …

Holocene Glacial History Of Renland, East Greenland Reconstructed From Lake Sediments, Aaron Medford

Electronic Theses and Dissertations

The Arctic is responding to the modern increase in temperature, resulting in ice loss and consequent sea-level rise. In order to understand present-day changes, we need to understand how the Arctic has reacted in the past to natural variations in climate forcing. To begin to identify the mechanisms behind climate change, I produced a Holocene glacial and climate record for the Renland Ice Cap, Scoresby Sund, East Greenland, from sediments in glacially fed lakes. I cored Rapids and Bunny Lakes, which are fed by meltwater from the Renland Ice Cap, as well as Raven Lake, which does not receive glacial …