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All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

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Full-Text Articles in Life Sciences

Biochemical Characterization Of Sac9, A Putative Phosphoinositide Phosphatase In Arabidopsis Thaliana, And Its Role In Cellular Abnormalities, Almut H. Vollmer May 2012

Biochemical Characterization Of Sac9, A Putative Phosphoinositide Phosphatase In Arabidopsis Thaliana, And Its Role In Cellular Abnormalities, Almut H. Vollmer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since the early colonization of land by fungi and plants some 700 million years ago, plants have been continuously faced with changes in their environment. Unlike animals, plants are not free to move about, and can therefore not evade many stress factors. How plants sense and respond to their environment has been of interest not only to scientific research but also in more practical applications such as agriculture.

Signals (such as light or salinity) from the outside of plant cells trigger a flow of information to the inside of the cell. The final target for most of the information is …


Mapping Fire Fuels Through Detection Of Canopy Biomass Loading In Juniper, Sagebrush, And Gambel Oak Communities, Sean Laroy Hammond May 2012

Mapping Fire Fuels Through Detection Of Canopy Biomass Loading In Juniper, Sagebrush, And Gambel Oak Communities, Sean Laroy Hammond

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fire fuel inventory processes are customarily labor intensive endeavors. There is a growing need for an increase in accuracy of these inventories at a landscape level, due in large part to the ever increasing development of Wildland Urban Interface (WUI). More accurate inventory and mapping of wildland fuels will facilitate a more accurate simulation of wildfire behavior and analysis of fire behavior given a myriad of fuels treatments. This paper examines one approach to inventorying fire fuels at a landscape level and developing fuel model maps to be utilized in landscape level fire behavior simulations for use by land managers …


A Case Study Of Professors' And Instructional Designers' Experiences In The Development Of Online Courses, Karl B. Stevens May 2012

A Case Study Of Professors' And Instructional Designers' Experiences In The Development Of Online Courses, Karl B. Stevens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of this study was to examine the experiences of instructional designers and professors during their efforts to develop online courses and to determine what effect their experiences had on the development process. Five professors and five instructional designers at Utah State University participated in this qualitative, single-case study. Participants were purposefully selected as matched pairs of development teams based on their respective levels of expertise in course development.

The ADDIE instructional design model was used as a conceptual framework to which emergent themes were aligned. ADDIE is an acronym for analysis, design, development, implementation, and evaluation. The key …


Social Organization And Decision Making In North American Bison: Implications For Management, Ryan A. Shaw May 2012

Social Organization And Decision Making In North American Bison: Implications For Management, Ryan A. Shaw

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Social organization varies widely among herbivores, and the level of social organization in bison is widely debated. I hypothesized that when mother-daughter relationships are allowed to develop, bison form long-term associations. In my study, 25 treatment mothers were selected from a free-ranging herd and kept together with their calves, while 25 control females had their calves forcefully removed. Treatment mothers and offspring had by far the greatest number of associations with a greater percentage of individuals with a half weight index (HWI) > 0.50. The strongest associations (HWI > 0.31) were among treatment mothers and their offspring. Moreover, these associations persisted over …


Parent Nutrition Education And The Influence On Family Lifestyle Behavior Changes, Kelsey Rich May 2012

Parent Nutrition Education And The Influence On Family Lifestyle Behavior Changes, Kelsey Rich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utah State University in the collaboration with the Supplemental Nutrition Assistance Program-Education (SNAP-Ed) proposes to develop and implement a program to help families develop healthy eating habits and lifestyle behaviors. Recently, childhood overweight and obesity has reached epidemic proportions. The diseases associated with adult obesity are now being seen in the pediatric population; therefore, there is a call for preventative efforts. A diet high in fruits, vegetables, and whole grains in combination with an active lifestyle discourages the presence of obesity. Currently, most childhood obesity prevention efforts have taken place in the school setting and have only had short term …


Livestock Foraging Behavior In Response To Sequence And Interactions Among Alkaloids, Tannins, And Saponins, Tiffanny L. Jensen May 2012

Livestock Foraging Behavior In Response To Sequence And Interactions Among Alkaloids, Tannins, And Saponins, Tiffanny L. Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

During the past several decades, people worldwide have expressed a growing interest in reconstructing ecosystems to enhance ecological, economic, and social values. Yet, to do so we must find ways to enhance biodiversity, environmental quality and the sustainability of grazing lands. In all these instances, plants are the glue that binds soils, water, herbivores, and people. However, monocultures or simple grass-legume mixtures are not always ideal for intensively managed pastures due to their seasonality, susceptibility to pests, and monotony of plant nutrients and toxins. All plants contain so-called “toxins,” more appropriately referred to as secondary compounds, which are crucial in …


In Vitro And In Vivo Comparison Of The Pathogenicity Of Four Influenza Virus Strains, Brett L. Hurst May 2012

In Vitro And In Vivo Comparison Of The Pathogenicity Of Four Influenza Virus Strains, Brett L. Hurst

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Influenza viruses cause between 3 and 5 million cases of respiratory infection each year and are responsible for between 250 and 500 thousand deaths. Two avenues for the treatment and prevention of influenza virus infections are vaccination and antiviral chemotherapy. Prevention is largely accomplished through vaccination. While vaccines remain the preferred method for controlling the spread of influenza, antiviral treatment is important for severe infections caused by new and emerging virus strains. Occasionally new viruses emerge to which the population has no previous immunity. Such was the case when the pandemic H1N1 influenza virus appeared in 2009. When new viruses …


Use Of Rumen Modifiers To Manipulate Ruminal Fermentation And Improve Nutrient Utilization And Lactational Performance Of Dairy Cows, Christopher M. Dschaak May 2012

Use Of Rumen Modifiers To Manipulate Ruminal Fermentation And Improve Nutrient Utilization And Lactational Performance Of Dairy Cows, Christopher M. Dschaak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of lactation studies reported in this dissertation hypothesized that supplementing different rumen modifiers would have consistent responses on ruminal fermentation and lactational performance under optimal rumen conditions.

The first experiment investigated the influence of magnesium exchanged zeolite on ruminal fermentation and lactational performance. Intake of dry matter (DM), milk yield, milk fat, and feed efficiency were not affected. Milk protein concentration tended (P = 0.15) to be higher for cows fed the zeolite. Ruminal pH tended to increase (P = 0.11) by feeding the sodium bicarbonate or the zeolite.

A second lactation experiment determined …


Caddisfly Larvae (Limnephilidae) As Predators Of Newt (Taricha Granulosa) Eggs: Another Player In The Coevolutionary Arms Race Revolving Around Tetrodotoxin?, Brian G. Gall May 2012

Caddisfly Larvae (Limnephilidae) As Predators Of Newt (Taricha Granulosa) Eggs: Another Player In The Coevolutionary Arms Race Revolving Around Tetrodotoxin?, Brian G. Gall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Some populations of newts (Taricha granulosa) possess large quantities of the neurotoxin tetrodotoxin (TTX) in their skin and eggs. Many populations of garter snake (Thamnophis sirtalis) are resistant to this toxin and can consume large numbers of newts with no negative effects. Despite the wealth of information acquired on the interaction between newts and their predator, garter snakes, very little research has been conducted on possible interactions between newts and other predators. I conducted a suite of experiments examining for the presence of other predators on newts, specifically focusing on predators of their eggs and larvae. …


Productivity Studies Utilizing Recombinant Cho Cells In Stirred-Tank Bioreactors: A Comparative Study Between The Pitch-Blade And The Packed-Bed Bioreactor Systems, Taylor Stephen Hatton May 2012

Productivity Studies Utilizing Recombinant Cho Cells In Stirred-Tank Bioreactors: A Comparative Study Between The Pitch-Blade And The Packed-Bed Bioreactor Systems, Taylor Stephen Hatton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Center for Integrated Biosystems (CIB) at Utah State University proposed to demonstrate the added benefits of bench top stirred-tank bioreactors utilizing the packedbed impeller system in perfusion mode for the production of recombinant proteins. In this study recombinant Chinese Hamster Ovary (CHO) cells were utilized for the production of a secreted protein in two bioreactor types: pitched-blade bioreactor operated in batch mode versus packed-bed bioreactor operated in perfusion mode. Our primary objective was to determine whether the packed-bed bioreactor is superior to a traditional pitched-blade bioreactor for the mass production of cell culture protein products. We hypothesize that the …


Modeling Freshwater Mussel Distribution In Relation To Biotic And Abiotic Habitat Variables In The Middle Fork John Day River, Oregon, Ericka E. Hegeman May 2012

Modeling Freshwater Mussel Distribution In Relation To Biotic And Abiotic Habitat Variables In The Middle Fork John Day River, Oregon, Ericka E. Hegeman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Freshwater mussels are the most threatened taxonomic group in North America with extinction rates that exceed those of many species found in both terrestrial and freshwater ecosystems including fish, birds, and amphibians. Part of the reason that mussels are so threatened is because their larvae are parasitic on fish, making the completion of their life cycle dependent upon healthy fish populations. The imperilment of freshwater mussels is a cause for concern because of the benefits that mussels provide to freshwater ecosystems including habitat enhancement, substratum stabilization, nutrient cycling, and water clarification. Restoration and conservation efforts targeting western freshwater mussels have …


Drivers Of Nest Success And Stochastic Population Dynamics Of The Common Eider (Somateria Mollissima), David Thomas Iles May 2012

Drivers Of Nest Success And Stochastic Population Dynamics Of The Common Eider (Somateria Mollissima), David Thomas Iles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human-caused climate alterations to Arctic ecosystems have resulted in a constellation of impacts on the biological relationships within them, yet the consequences of these changes on the population dynamics of many species are poorly understood. Thus, an understanding of the drivers of variation in population performance is needed to inform the management and conservation of imperiled species. Here, we use a long-term dataset for the common eider, an Arctic-breeding sea duck, to examine the drivers of annual variation in nest survival, and evaluate the effects of variation in vital rates on population growth. Our chapter 2 results suggested that increased …


Identifying And Quantifying Sediment Sources And Sinks In The Root River, Southeastern Minnesota, Justin Collin Stout May 2012

Identifying And Quantifying Sediment Sources And Sinks In The Root River, Southeastern Minnesota, Justin Collin Stout

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fine sediment, normally understood to refer to sand, silts, and clays; is a natural constituent in all rivers. When in excess this fine sediment can degrade the habitat for aquatic life in these rivers, and carry with it many pollutants and nutrients which can cause adverse effects on wildlife and human populations.

Understanding how this fine sediment moves through a river system, from erosion off of hillslopes, transport through the river, and finally export from the mouth of the system is vital part to land and river management. However, predicting how fine sediment moves through a system is a difficult …


Orchard Floor Management, Marc A. Rowley Dec 2011

Orchard Floor Management, Marc A. Rowley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Managing fruit orchards involves both the management of the orchard trees, and the orchard floor. Orchard floor management is vital to tree health, yield and fruit quality. Current standard management practices include maintaining a vegetation free tree row and a grass-covered alleyway. This system effectively controls weeds and creates a favorable environment for the fruit trees. However, limitations to standard orchard floor practices are that the grass alleyway provides no nutrient benefit, and current practices do not readily lend themselves to organic management. Alternative in-row and alleyway systems are requisite to creating improved orchard floor management systems.

Three different approaches …


Seasonal Transport Of Suspended Solids And Nutrients Between Bear River And Bear Lake, Cody M. Allen Dec 2011

Seasonal Transport Of Suspended Solids And Nutrients Between Bear River And Bear Lake, Cody M. Allen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I measured inflows and outflows of nutrients and suspended solid through the wetland complex, known as Dingle Marsh, at the Bear River Migratory Bird Refuge between October 2007 and September 2008. My analysis of changes throughout the year will help Dingle Marsh managers adjust the timing and volume of water movement between Bear River and Bear Lake to meet defined refuge goals, such as improving bird or other animal habitat. These results could also be used to protect Bear Lake’s water quality.

Automated samplers took readings of dissolved oxygen, turbidity, pH and water temperature every 30 minutes. These values were …


Genetic Status Of Isolated Populations Of Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus) In The North Fork Little Snake River Drainage, Wyoming, Rachel Van Horne Dec 2011

Genetic Status Of Isolated Populations Of Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus) In The North Fork Little Snake River Drainage, Wyoming, Rachel Van Horne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Over the last century native cutthroat trout populations have declined in the western United States. Habitat fragmentation is one of the main causes for this decline. Human actions such as the construction of roads, weirs, dams, and water diversions intersect streams and prevent the natural movement of fish. In many cases native cutthroat trout are now confined to headwater streams above human-created barriers. These barriers not only fragment the populations but also increase the risk of individual population extinction.

This study established a baseline genetic structure for nine isolated populations of Colorado River cutthroat trout in the North Fork Little …


The Biogeography Of Marbled Godwit (Limosa Fedoa) Populations In North America, Bridget E. Olson Dec 2011

The Biogeography Of Marbled Godwit (Limosa Fedoa) Populations In North America, Bridget E. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mission of the U.S. Fish and Wildlife Service (USFWS) is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. Toward fulfillment of that mission, a priority of the USFWS is conservation and management of migratory birds. Effective conservation actions to ensure the continued existence of a species on the landscape cannot be designed without first understanding basic life history characteristics of a species. It is common in the case of migratory birds, that we lack understanding of some of their elemental biological traits.

The Marbled Godwit, …


Effect Of Voluntary Exercise And Diet On The Unfolded Protein Response In The Brain Of Mice, Yu Ho Kim Dec 2011

Effect Of Voluntary Exercise And Diet On The Unfolded Protein Response In The Brain Of Mice, Yu Ho Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The medical costs for many chronic diseases are increasing dramatically and placing a major financial burden on nations and individuals in both developed and developing countries. A number of chronic diseases, such as obesity, type 2 diabetes and some neurodegenerative diseases are all attenuated by a history of physical activity suggesting that they may be interconnected in some way. It has been suggested that cellular stress is a major factor promoting these chronic diseases.

Cellular stress occurs in a specific compartment within the cell, the endoplasmic reticulum, whose normal function is in the synthesis and folding of proteins into the …


Relative Importance Of Environmental Variables For Spawning Cues And Tributary Use By An Adfluvial Lake Sucker, Brian A. Hines Dec 2011

Relative Importance Of Environmental Variables For Spawning Cues And Tributary Use By An Adfluvial Lake Sucker, Brian A. Hines

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The endangered June sucker (Chasmistes liorus mictus), which is only found in Utah Lake, UT, historically spawned in all streams flowing into the lake, but due to human-caused changes their spawning is restricted to the Provo River. The purpose of this study was to gain a better understanding of the spawning and early life-history of the
June sucker for recovery purposes. My specific objectives were to determine:

  1. what environmental factors attract or deter June suckers to certain Utah Lake tributaries for spawning,
  2. what cues June suckers to migrate upstream to spawn,
  3. if June suckers use more than one …


Effects Of Tannin-Containing Feed On Haemonchous Contortus In Sheep And Its Behavioral Implications, Jessica A. Juhnke Dec 2011

Effects Of Tannin-Containing Feed On Haemonchous Contortus In Sheep And Its Behavioral Implications, Jessica A. Juhnke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Herbivores prefer foods that supply required nutrients and avoid those with excess nutrients and plant secondary compounds (PSC). Nevertheless, PSC such as condensed tannins can provide beneficial medicinal effects to herbivores. The objectives of this study were to determine: 1) if parasitized lambs increased preference for a tannin-rich food after they experienced the beneficial antiparasitic effects of tannins relative to parasitized lambs that did not experience such benefits, 2) if preference for the tannin-containing food in the former group decreased when parasite burdens subsided, and 3) if the tannin-enriched food decreased parasitic burdens.

Twenty-two lambs were familiarized with beet pulp …


Molecular Interactions Of Salmonella With The Host Epithelium In Presence Of Commensals, Prerak T. Desai Dec 2011

Molecular Interactions Of Salmonella With The Host Epithelium In Presence Of Commensals, Prerak T. Desai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Food-borne infections are a major source of mortality and morbidity. Salmonella causes the highest number of Food-borne bacterial infections in the US. This work contributes towards developing strategies to control Salmonella by (a) defining receptors used by Salmonella to adhere to and invade the host epithelium; (b) developing a host receptor based rapid detection method for the pathogen in food matrix; (C) and defining mechanisms of how probiotics can help alleviate Salmonella-induced cell death in the host epithelium.

We developed a cell-cell crosslinking method to discover host-microbe receptors, and discovered three new receptor-ligand interactions. Interaction of Salmonella Ef-Tu with …


Have Introduced Brown Trout (Salmo Trutta) Affected Native Aquatic Vertebrates In Western United States Streams?, Nora K. Burbank Dec 2011

Have Introduced Brown Trout (Salmo Trutta) Affected Native Aquatic Vertebrates In Western United States Streams?, Nora K. Burbank

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The introduction of exotic species to areas outside of their native range is one of the greatest threats to the biodiversity of native freshwater organisms. Exotic species have outcompeted native species for resources such as food and shelter, and in some cases these interactions have resulted in local extinctions or reductions in abundance of those native species. Brown trout are native to Eurasia, but have been introduced to much of the rest of the world, including the United States. In some parts of their introduced range, brown trout have substantially reduced the abundance and home ranges of some native fish …


Characterizing Water And Nitrogen Dynamics In Urban/Suburban Landscapes, Hongyan Sun Dec 2011

Characterizing Water And Nitrogen Dynamics In Urban/Suburban Landscapes, Hongyan Sun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigated the water use of different plant types in urban landscapes, nitrogen (N) and water transport in turf, and potential N leaching from urban landscapes to ground water. In the first study, three landscape treatments integrating different types of plants—woody, herbaceous perennial, turf—and putative water use classifications—Mesic, Mixed, Xeric—were grown in large drainage lysimeters. Each landscape plot was divided into woody, turf, and herbaceous perennial plant hydrozones and irrigated for optimum water status over two years, with water use measured using a water balance approach. For woody plants and herbaceous perennials, canopy cover, rather than plant type or …


Isotopic Tracer Reveals Depth-Specific Water Use Patterns Between Two Adjacent Native And Non-Native Plant Communities, Clémence Pascale Warren Dec 2011

Isotopic Tracer Reveals Depth-Specific Water Use Patterns Between Two Adjacent Native And Non-Native Plant Communities, Clémence Pascale Warren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-native plants have invaded over 100 millions of acres of western arid land in the US and dramatically altered nutrient cycling rates. Changes in water cycling caused by invasive species are of particular interest because primary production in the Western US is typically limited by water availability and aquifer recharge reflects plant demand. Large-scale invasions can, therefore, be expected to cause large-scale changes in hydrological cycles, but until recently, there have been considerable limitations in the ability to measure the timing, location, and extent of water use. Here we injected a tracer, deuterated water (D2O), into five soil …


An Assessment Of Vegetation Metrics And Plot Types To Measure Seasonal Variation And Grazing Effects On Riparian Plant Communities, Caroline M. Laine Dec 2011

An Assessment Of Vegetation Metrics And Plot Types To Measure Seasonal Variation And Grazing Effects On Riparian Plant Communities, Caroline M. Laine

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Monitoring changes in vegetation is important on public lands. Observing how plant communities respond to changes in land management can give insightful information about which management practices are sustainable. Because water is scarce in the western United States, many land managers focus their monitoring efforts along streams. However, monitoring streamside vegetation is challenging due to a variety of factors and can be confounded by factors such as seasonal climate variation and management activities, like cattle grazing.

In vegetation assessment, there are a variety of measurements that are taken to glean valuable information. Some attributes of interest include how much vegetation …


Analysis Of Food Web Effects Of Non-Native Fishes And Evaluation Of Stream Restoration Potential For The San Rafael River, Utah, Timothy E. Walsworth Dec 2011

Analysis Of Food Web Effects Of Non-Native Fishes And Evaluation Of Stream Restoration Potential For The San Rafael River, Utah, Timothy E. Walsworth

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Native fishes of the Colorado River Basin have experienced dramatic reductions in range and abundance as a result of extensive human alterations to the basin’s waterways. Many of these native fishes are federally listed under the Endangered Species Act, while several others are subject to range-wide conservation agreements between state and federal management agencies. Three of the native species subject to range-wide conservation agreements are the flannelmouth sucker, bluehead sucker, and roundtail chub (hereafter, the “three species”). Each of the “three species” is still found in the San Rafael River of southeastern Utah, which has experienced habitat degradation and non-native …


Assessment Of Colorado’S Wilderness Areas: Manager Perceptions And Remoteness Modeling, Gary D. Vaughn Dec 2011

Assessment Of Colorado’S Wilderness Areas: Manager Perceptions And Remoteness Modeling, Gary D. Vaughn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study assessed visitor use levels and resource and social conditions in wilderness areas across the State of Colorado using existing and collected spatial data. This is the first attempt to spatially assess wilderness conditions at the state level. A state-wide assessment of wilderness conditions allows local and regional managers to make informed regional decisions and to prioritize and direct their time and energy efficiently. This assessment clarifies the recreational use and impacts across the state. This study consists of two projects: 1) managers’ perceptions of the location and extent of resource and social condition problems; and 2) a geographic …


Using Species Distribution Models To Assess Invasion Theory And Provide Management Recommendations For Riparian Areas In The Eastern Columbia And Western Missouri River Basins, Diane R. Menuz Dec 2011

Using Species Distribution Models To Assess Invasion Theory And Provide Management Recommendations For Riparian Areas In The Eastern Columbia And Western Missouri River Basins, Diane R. Menuz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Globalization has created opportunities for plant and animal species to be transported to novel ecosystems. A subset of these species become invasive species, which are able to persist and spread rapidly to become influential components in their new ecosystems. Invasive species are often able to out-compete co-occurring native species and can alter fundamental ecosystem properties, such as soil nutrient availability or time between wildfires in a region. The United States is estimated to lose $34 billion per year to invasive plant species through costs to control unwanted species and lowered crop and forage production.

We used statistical models to better …


Reconstructing The Holocene Arroyo History Of The Upper Escalante River, Southern Utah, Using Optically Stimulated Luminescence (Osl) And Radiocarbon Dating, Anne E. Hayden Dec 2011

Reconstructing The Holocene Arroyo History Of The Upper Escalante River, Southern Utah, Using Optically Stimulated Luminescence (Osl) And Radiocarbon Dating, Anne E. Hayden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Arroyos are steep-walled, entrenched, typically ephemeral streams commonly found in dryland river systems that form when streams incise into previously deposited alluvial fill. Arroyos in the southwestern U.S. have been studied extensively following the historic period of arroyo cutting in the late 1800s and early 1900s A.D. The upper Escalante River in south-central Utah similarly began incising in 1909, and records evidence for past cut and fill cycles in well-exposed walls along the now continuous arroyo.

Establishing robust geochronologies of past arroyo cycles in these fluvial settings has been difficult. Recent improvements in accelerator mass spectrometry (AMS) radiocarbon (14 …


Rotating Algal Biofilm Reactors: Mathematical Modeling And Lipid Production, Paul A. Woolsey Dec 2011

Rotating Algal Biofilm Reactors: Mathematical Modeling And Lipid Production, Paul A. Woolsey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Harvesting of algal biomass presents a large barrier to the success of biofuels made from algae feedstock. Small cell sizes coupled with dilute concentrations of biomass in lagoon systems make separation an expensive and energy intense-process. The rotating algal biofilm reactor (RABR) has been developed at USU to provide a sustainable technology solution to this issue. Algae cells grown as a biofilm are concentrated in one location for ease of harvesting of high density biomass. A mathematical model of this biofilm system was developed based on data generated from three pilot scale reactors at the City of Logan, Utah wastewater …