Life Sciences Commons^™

Bone Mineral Density Of The Common Bottlenose Dolphin, Tursiops Truncatus: A Proposed Model For Monitoring Osteological And Ecosystem Health, James Wright Burrus Powell

Dissertations and Theses

Bone mineral density (BMD) in the pectoral flipper of the common bottlenose dolphin, Tursiops truncatus, was examined to address the need to define a comprehensive target site for clinical osteodensitometric assessment and to establish ranges of observed bone density values for this species. Radii were analyzed using dual energy X-ray absorptiometry (DXA), the accepted standard in human medical studies. Multiple loci within the radius were identified and assessed for their correlation to BMD of the entire bone. Radii BMD were also examined for differences based on sex, age, total body length, handedness, geographical affinity, and nutritional status at time …

Tracking Center Of Mass With Limited Inertial Measurement Units, Connor Nathaniel Morrow

Dissertations and Theses

Wearable motion tracking systems pose an opportunity to study and correct human balance and posture during movement. Currently, these observations are either being conducted in laboratories with the use of camera systems and markers placed on the body, or through the use of suits containing large numbers (15-20) of inertial measurement units. However, to aid with rehabilitation of individuals with impaired balance, there needs to be an option to collect these observations outside of clinics and without incurring much cost from the user. I have focused on three inertial measurement units, one placed on each shank and one placed on …

Avian Dispersal Networks, Metacommunity Structure, And Bryophyte Community Assemblages, Matthew Wojciech Chmielewski

Dissertations and Theses

Spatial processes have a profound influence on the structure and function of community assemblages. The dispersal of organisms from their place of origin to the location in which they live out their reproductive life is particularly important for plant communities, which generally cannot adjust their location post-germination. Connection between communities at a landscape scale can also influence species persistence, local and regional diversity, and functional turnover at the metacommunity scale. Animals have been shown to disproportionately deposit propagules in particular microsites in many plant species, facilitating the arrival of plants to appropriate niche-space. Birds are particularly notable seed dispersers, given …

Parr Going The Distance: How Migratory Difficulty Influences Red Muscle Lipid Storage In Juvenile Oncorhynchus Mykiss, Emily Jean Morse

Dissertations and Theses

Adult salmonid populations embarking on difficult migrations have evolved to store more somatic energy prior to river entry. While it is known that lipids are the primary fuel for endurance swimming in fish, uncertainty still surrounds how these mechanisms are utilized by juvenile fish during seaward migration. A key phase in salmonid migration is the preparatory season of feeding and growth before swimming downstream. During this period, juvenile fish build somatic fuel stores through dietary uptake. Intestinal microbiota of steelhead trout (Oncorhynchus mykiss) vary drastically across their geographic range, with significant differences in the coastal and inland subspecies' …

The Fate Of Atmospherically Deposited Mercury In Mountain Lake Food Webs, And Implications For Fisheries Management, Ariana Martos Chiapella

Dissertations and Theses

Mountain lakes are an iconic feature of the landscape in the Mountain West. They hold significant ecological and cultural value, and are important sentinels of environmental change. Despite their pristine image, these remote waterbodies are subjected to numerous anthropogenic stressors. Mountain lakes are naturally fishless systems, but historical fish stocking has led to major changes in mountain lake food web structure, including declines of resident amphibians, large-bodied zooplankton, and emergent insect populations. Atmospherically deposited contaminants, such as mercury, can accumulate in mountain lake food webs, leading to relatively high levels in the fish relative to the water. Managing for these …

Use Of Two-Replisome Plasmids To Characterize How Chromosome Replication Completes, Nicklas Alexander Hamilton

Dissertations and Theses

All living organisms need to accurately replicate their genome to survive. Genomic replication occurs in three phases; initiation, elongation, and completion. While initiation and elongation have been extensively characterized, less is known about how replication completes. In Escherichia coli completion occurs at sites where two replication forks converge and is proposed to involve the transiently bypass of the forks, before the overlapping sequences are resected and joined. The reaction requires RecBCD, and involves several other gene products including RecG, ExoI, and SbcDC but can occur independent of recombination or RecA. While several proteins are known to be involved, how they …

An Examination Of Non-Waged Labor And Local Food Movement Growth In The Southern Appalachians, Amy Kathryn Marion

Dissertations and Theses

Farmers have traditionally depended on their families or paid employees to cover their extensive labor needs. Today, non-waged labor models are gaining popularity, especially among small, ecologically-oriented farms. Apprenticeships and internships can be a primary form of training for a population of new and beginning farmers, many of whom are entering the field without farming backgrounds. However, many question the sustainability and justness of these arrangements. As a new phenomenon, very little research examines the relationship between non-waged labor models like agricultural apprenticeships and alternative food movements. In this exploratory study, the author surveyed nearly 250 farmers growing for local …

Sensors And Portable Instruments For Postharvest Agriculture, Ryan M. Lerud

Dissertations and Theses

The sensing needs for the fresh produce industry can be split into two primary stages: during maturation in the field, also referred to as Precision Farming, and during storage and transport of the produce, or Postharvest Storage. This work seeks to improve the accuracy and reliability of commercially available electrochemical and spectroscopic sensors tailored to the sensing needs of the fresh produce industry. For electrochemical sensing, this study proposes the use of an inline filter to remove polar organic compounds, which can interfere with the readings of a platinum-based electrochemical sensor. A 50% improvement in measurement accuracy was achieved when …

Application Of Single Particle Electron Microscopy To Native Lens Gap Junctions And Intrinsically Disordered Signaling Complexes, Janette Bernadette Myers

Dissertations and Theses

Gap junctions are a class of membrane proteins that facilitate cell-to-cell communication by forming channels that directly couple the cytoplasm of neighboring cells. The channels are composed of monomers called connexins. Humans express 21 connexin isoforms in a cell-type specific fashion, and each isoform has distinct mechanisms of permeation and regulation. Co-assembly of multiple isoforms into a single intercellular channel can change channel properties, such as conductance and selectivity to substrates (e.g., ions, metabolites and signaling molecules). However, the mechanistic basis for this functional diversity has remained poorly understood. This lack of mechanistic insight has been due in large part …

A Mendelian Randomization Study Of Coronary Artery Disease And Three Amino Acids: Alanine, Glycine, And Glutamine, Allan Uribe

Dissertations and Theses

Cardiovascular disease is the leading cause of death worldwide. Coronary Artery Disease (CAD) accounts for the majority of those deaths. Observational studies have identified risk factors that have been helpful in lowering the death rate, including hypertension, high cholesterol, diabetes, smoking, physical inactivity and poor diet. The effects of these risk factors on CAD remain unclear. To clarify the effect of three amino acids, alanine, glutamine, and glycine on CAD I applied a two sample Mendelian randomization analysis to extensively genotyped observational data. In a sample with up to 184,000 individuals and approximately 60,000 controls, SNPs that reached genome wide …

Tree Canopy Cover And Potential In Portland, Or: A Spatial Analysis Of The Urban Forest And Capacity For Growth, Jeff Ramsey

Dissertations and Theses

Urban forests have positive impacts on human and ecosystem health, reduce stress on aging stormwater infrastructure, increase property values, and reduce energy consumption. The scale of these benefits ranges from the hyper-local to the global. While the benefits of urban forests can extend well beyond the boundaries of cities, they often do not reach all residents of the city equally. Urban forest policies do not adequately address environmental equity or employ planting strategies with knowledge of the social and political factors that determine the spatial variations of tree canopy extent in cities. Chapter I analyzes the determinants of current canopy …

Snowy Plover Demography In Oregon, Eleanor Prindiville Gaines

Dissertations and Theses

A thorough understanding of demographic parameters and their contribution to overall population growth is fundamental to effective conservation of small populations, but this information is often lacking. The Pacific Coast population of the Western Snowy Plover (Charadrius nivosus nivosus) is listed as threatened and has been the target of long-term, multi-pronged management in Oregon. The Oregon coastal population has been intensively monitored since 1990, and over 80% of the population is color banded, but a comprehensive analysis of demographic parameters and the effect of management on vital rates and population growth has been unavailable until now. Here, the …

Isoprene Emission In Polytrichaceae Mosses, Timea Deakova

Dissertations and Theses

Our first aim was to identify and quantify Biological Volatile Organic Compound (BVOC) emissions, specifically emissions of isoprene, from the moss Polytrichum juniperinum during its earliest stage of life. Isoprene emission from mosses could be a significant component of the total global budget of BVOC emissions. Data concerning the spatial and temporal variability of these emissions are lacking due to poor characterization of the physical and biological factors controlling isoprene synthesis in both vascular and non-vascular plants. We found that P. juniperinum in its early life stage (protonema) can emit isoprene at detectable levels at day five after spore germination. …

The Interactive Effect Of Temperature And Salinity In The Nile Tilapia (Oreochromis Niloticus), Rachel Marie Palmer

Dissertations and Theses

Frequent measures that aim to identify the tolerance of an organism to various environmental conditions rely on the mortality of said organism. However, the effects of sub-lethal stress can be just as important to consider as they may give rise to how an organism may live in such an environment (growth, reproduction, etc.). Coping with changes in environmental conditions can have a high energy cost. Even starting a cellular stress response alone has proven to be costly. It is therefore reasonable that organisms in stressful situations will dedicate energy sources to survival mechanisms, and downregulate non-necessary activities like growth, and …

The Influence Of Hibernation Temperature On Deiodinase 2 In Red-Sided Garter Snakes (Thamnophis Sirtalis Parietalis), Kalera Stratton

Dissertations and Theses

Environmental cues such as day length and temperature contribute to timing of biological rhythms in seasonal breeders. Life-history transitions such as spring emergence from hibernation, migration, or mating must be coordinated with environmental conditions or survival is compromised. Therefore, there must be chemical signaling pathways in the brain that transduce seasonally-changing sensory inputs into signals that initiate a hormonal cascade, culminating in reproductive behavior. The relative importance of environmental cues to reproductive timing varies with species, time of year, and sex, and the mechanisms driving these differences remain unknown. The role of photoperiod in regulating reproductive behavior has been explored …

Symbiosis In Archaea: Functional And Phylogenetic Diversity Of Marine And Terrestrial Nanoarchaeota And Their Hosts, Emily Joyce St. John

Dissertations and Theses

The Nanoarchaeota are an enigmatic lineage of Archaea found in deep-sea hydrothermal vents and geothermal springs across the globe. These small (~100-400 nm) hyperthermophiles live ectosymbiotically with diverse hosts from the Crenarchaeota. Despite their broad distribution in high-temperature environments, very few Nanoarchaeota have been successfully isolated in co-culture with their hosts and nanoarchaeote genomes are poorly represented in public databases. However, the Nanoarchaeota provide unique insights into the structure and function of symbiosis in the archaeal domain. This study describes novel nanoarchaeotes from multiple geothermal habitats, using a combination of direct cultivation techniques and genomic analysis. A new nanoarchaeote …

Scientists, Uncertainty And Nature, An Analysis Of The Development, Implementation And Unintended Consequences Of The Northwest Forest Plan, Gilbert David Miller

Dissertations and Theses

The conflict in the Pacific Northwest between competing visions of how federal forests should be managed resulted in a political stalemate in the early 1990s. The Northwest Forest Plan (NWFP) was initiated to resolve the demands for maintaining ecosystem processes and biological diversity with the social and economic needs for timber harvest. The foundation for the plan rested with the development of ecosystem management. The intent of this research is to explore the events which led up to the adoption of the NWFP, how it was implemented by the US Forest Service and Bureau of Land Management and the subsequent …

The Effect Of Dynamic Kinetic Selection On An Evolving Ribozyme Population, Patrick David Poletti

Dissertations and Theses

Dynamic Kinetic Selection (DKS) suggests that kinetic, rather than thermodynamic, stability will dictate the composition of a replicating population of biomolecules. Here, the results obtained from a series of five related reactions involving gradually increasing percentages of randomly-mutated substrate fragments to generate variants of full-length Azoarcus group I intron through an autocatalytic self-assembly reaction involving a series of recombination events, showed DKS as a driving factor in dictating the population composition of full-length product assembled from substrates that had fewer positions available to randomization.

In trying to elucidate a plausible scheme for the origins of complex biomolecules on the prebiotic …

Mechanisms Of Microglia Mediated Apolipoprotien E Neurotoxicity, Pardeep Singh

Dissertations and Theses

No abstract provided.

Using Fundamental Properties Of Light To Investigate Photonic Effects In Condensed Matter And Biological Tissues, Laura A. Sordillo

Dissertations and Theses

Light possesses characteristics such as polarization, wavelength and coherence. The interaction of light and matter, whether in a semiconductor or in a biological sample, can reveal important information about the internal properties of a system. My thesis focuses on two areas: photocarriers in gallium arsenide and biomedical optics. Varying the excitation wavelength can be used to study both biological tissue and condensed matter. I altered the excitation wavelengths to be in the longer near-infrared (NIR) optical windows, in the shortwave infrared (SWIR) range, a wavelength region previously thought to be unusable for medical imaging. With this method, I acquired high …

Multi-Locus Phylogenetic Inference Of The Howler Monkey (Alouatta) Radiation In South America., Esmeralda Ferreira

Dissertations and Theses

Abstract

Howler monkeys (Alouatta) are the most widely distributed New World primates, ranging from southern Mexico to northern Argentina. They occur in tropical rain forests, flooded and gallery forests, and deciduous and semi-deciduous environments. Despite their importance as seed dispersers, howlers have also been known to be ecological indicators. Available phylogenetic hypotheses for this genus have used chromosomal characters, morphological characteristics, and a limited number of molecular markers and specimens. In spite of these analyses, branching patterns among howler species lineages conflict between studies or remain unresolved. Using 14 unlinked non-coding intergenic nuclear regions under both a concatenated …

Do Saproxylic Curculionids Affect The Fitness Of Co-Occurring Cerambycids?, Sheila R. Heath

Dissertations and Theses

Saproxylic insects sometimes coexist in incredibly high numbers under bark and share common resources. Thus, interactions between species are possible and could even explain their coexistence. This study investigates evidence of negative or positive effects of curculionid beetles (Coleoptera: Curculionidae) on cerambycid beetles (Coleoptera: Cerambycidae) that coexisted in dead tree branches in Costa Rica. Co-occurrence analysis and generalized regressions were used to test associations between cerambycid and curculionid species. Three cerambycid species that each co-occurred with a curculionid species were selected to measure fitness. Fitness measures of the cerambycid were compared with abundance of the co-occurring curculionid to assess the …