Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 4081 - 4110 of 10994

Full-Text Articles in Entire DC Network

Understanding The Diversification Of Central American Freshwater Fishes Using Comparative Phylogeography And Species Delimitation, Justin C. Bagley Dec 2014

Understanding The Diversification Of Central American Freshwater Fishes Using Comparative Phylogeography And Species Delimitation, Justin C. Bagley

Theses and Dissertations

Phylogeography and molecular phylogenetics have proven remarkably useful for understanding the patterns and processes influencing historical diversification of biotic lineages at and below the species level, as well as delimiting morphologically cryptic species. In this dissertation, I used an integrative approach coupling comparative phylogeography and coalescent-based species delimitation to improve our understanding of the biogeography and species limits of Central American freshwater fishes. In Chapter 1, I conducted a literature review of the contributions of phylogeography to understanding the origins and maintenance of lower Central American biodiversity, in light of the geological and ecological setting. I highlighted emerging phylogeographic patterns, …

Go to article

The Word Problem Factor: Assessing The Ability Of Utah High School Career And Technical Education Students To Do The Math Involved In Formulating And Calculating Energy Cost Factors, Kristen Bentley Dec 2014

The Word Problem Factor: Assessing The Ability Of Utah High School Career And Technical Education Students To Do The Math Involved In Formulating And Calculating Energy Cost Factors, Kristen Bentley

Theses and Dissertations

Much research has been done showing the difficulty people have with word problems. This has been shown to be true for many types of word problems and for different demographics. Questions have remained unanswered regarding the reasons for this difficulty. It has been unclear if the word problems were hard because the people had forgotten or had not yet learned how to do the math calculations involved or for some other reason. This study deals with high school students who are currently in a high school level math class. They were given an assessment involving word problems and number-only problems. …

Go to article

Spatial Heterogeneity Of Ecosystem Metabolism In A Shallow Wetland, Daniel Riley Rackliffe Dec 2014

Spatial Heterogeneity Of Ecosystem Metabolism In A Shallow Wetland, Daniel Riley Rackliffe

Theses and Dissertations

Spatial heterogeneity in ecosystem metabolism may play a critical role in determining ecosystem functions. Variation in ecosystem metabolism between macrophyte patches in shallow wetlands at the extremes of freshwater habitats has not been investigated. We estimated ecosystem metabolism in mesocosms containing different macrophytes using 24-hour oxygen curves to test our hypotheses: (1) net aquatic production (NAP) during spring and summer would be similar among algal patches (metaphyton and Chara), (2) NAP in algal patches would be greater than patches dominated by the vascular plant Potamogeton foliosus, (3) heterotrophy and anaerobiosis would be greatest in patches dominated by Lemna, and (4) …

Go to article

A Molecular Phylogeny Of Lampyridae With Insight Into Visual And Bioluminescent Evolution, Gavin Jon Martin Dec 2014

A Molecular Phylogeny Of Lampyridae With Insight Into Visual And Bioluminescent Evolution, Gavin Jon Martin

Theses and Dissertations

Fireflies are some of the most captivating organisms on the planet. Because of this, they have a rich history of study, especially concerning their bioluminescent and visual behavior. Among insects, opsin copy number variation has been shown to be quite diverse. However, within the beetles, very little work on opsins has been conducted. Here we look at the visual system of fireflies (Coleoptera: Lampyridae), which offer an elegant system in which to study visual evolution as it relates to their behavior and broader ecology. They are the best-known case of a terrestrial organism that communicates through the use bioluminescence. The …

Go to article

The Effects Of Nebulized Saline Treatments On Diphthongal Vowel Production On Female Subjects With Sjögren's Syndrome, Keri Lynn Perry Dec 2014

The Effects Of Nebulized Saline Treatments On Diphthongal Vowel Production On Female Subjects With Sjögren's Syndrome, Keri Lynn Perry

Theses and Dissertations

The purpose of this study was to analyze and quantify the effects of a nebulized saline treatment on speech production in eight females with Primary Sjögren's Syndrome (SS). The duration, formant frequency onset and offset, and slope were measured to determine the quality of participants' production of diphthongal American English vowels. Acoustic data were examined before treatment began, immediately following treatment, and during a one-week follow-up to determine the effects of a laryngeal hydration program that used nebulized saline to increase hydration of structures in the vocal tract. The vowels produced during the initial baseline condition were acoustically relatively similar …

Go to article

Microvascular Function In Metabolically Healthy Groups Differing In Bmi And Waist Circumference, Nathan R. Earl Dec 2014

Microvascular Function In Metabolically Healthy Groups Differing In Bmi And Waist Circumference, Nathan R. Earl

Theses and Dissertations

BACKGROUND: Microvascular dysfunction (MD: impaired performance of blood flow, tissue perfusion, blood pressure, etc.) is one of the earliest stages in the progression of various chronic diseases. OBJECTIVE: The aim of this study was to determine if a difference in microvascular function existed between two metabolically healthy groups that differed in BMI and waist circumference. DESIGN: This study employed a causal comparative design, with two groups: I) normal weight (n =14, BMI 28 kg/m2). METHODS: Microvascular function was assessed by measuring skin blood flow (SkBF) using laser Doppler flowmetry during postocclusive reactive hyperemia (PORH). The area under the SkBF time …

Go to article

Studies Of Phou In Escherichia Coli: Metal Binding, Dimerization,Protein/Protein Interactions, And A Signaling Complex Model, Stewart G. Gardner Dec 2014

Studies Of Phou In Escherichia Coli: Metal Binding, Dimerization,Protein/Protein Interactions, And A Signaling Complex Model, Stewart G. Gardner

Theses and Dissertations

Phosphate is an essential nutrient for all forms of life. Escherichia coli has a PhoR/PhoB two component regulatory system that controls the expression of various genes whose products allow the cell to thrive in low phosphate environments. The signaling mechanism of the PhoR/PhoB system has been studied and the phosphorylation cascade that controls gene expression is well understood. What is still unknown is how PhoR senses the phosphate level of the environment. The PstS, PstC, PstA, PstB, and PhoU proteins play a role in this signal sensing. This work confirms the hypothesis that the PstSCAB complex senses the environmental phosphate …

Go to article

Variation In Resource Utilization And Cost Of Reproduction For Two Burying Beetle Species, Peter J. Meyers Dec 2014

Variation In Resource Utilization And Cost Of Reproduction For Two Burying Beetle Species, Peter J. Meyers

Theses and Dissertations

The cost of reproduction hypothesis suggests that allocation into current reproduction constrains future reproduction. How organisms accrue reproductive costs may differ between species and with varying levels of resource quality. Burying beetles are model organisms for testing for the cost of reproduction because of their unique natural history; beetles utilize small vertebrate carcasses for reproduction and they and their offspring feed exclusively on these discrete resources. Burying beetles also can utilize a large range of carcass sizes for reproduction. We tested for the cost of reproduction in two species of burying beetles, Nicrophorus marginatus and Nicrophorus guttula found in Central …

Go to article

Alcohol Modulation Of Dopamine Release, Nathan Dan Schilaty Dec 2014

Alcohol Modulation Of Dopamine Release, Nathan Dan Schilaty

Theses and Dissertations

The mesolimbic dopamine (DA) system projects from the ventral tegmental area (VTA) to structures associated with the limbic system, primarily the nucleus accumbens (NAc). This system has been implicated in the rewarding effects of drugs of abuse. Many drugs of abuse act in the VTA, the NAc, or both. Dopamine neurons in the VTA that project to the NAc, and the GABA neurons that inhibit DA neurons locally in the VTA or project to the NAc, play an important role in mediating addiction to various drugs of abuse, in particular alcohol. There is a growing body of evidence of co-dependence …

Go to article

The Impacts Of Feral Horses On The Use Of Water By Pronghorn On The Sheldon National Wildlife Refuge, Nevada, Amy Marie Gooch Dec 2014

The Impacts Of Feral Horses On The Use Of Water By Pronghorn On The Sheldon National Wildlife Refuge, Nevada, Amy Marie Gooch

Theses and Dissertations

Feral horses occupy 31.6 million acres throughout western North America. Feral horses share similar habitats with a wide range of animal species, including pronghorn. Since horses are larger and often more aggressive than other animals of this region, they are generally socially dominant over all other native ungulate species. Pronghorn share water sources with horses in areas where both occur. In situations where horses exclude pronghorn from water, pronghorn fitness may be impaired, especially during the hottest months of the year when water is limited. The purpose of this study was to investigate interference competition between pronghorn and feral horses …

Go to article

Enhancing Protein And Enzyme Stability Through Rationally Engineered Site-Specific Immobilization Utilizing Non-Canonical Amino Acids, Jeffrey Chun Wu Dec 2014

Enhancing Protein And Enzyme Stability Through Rationally Engineered Site-Specific Immobilization Utilizing Non-Canonical Amino Acids, Jeffrey Chun Wu

Theses and Dissertations

The demand for economical, efficient protein production, reuse, and recovery has never been greater due to their versatility in a large variety of applications ranging from industrial chemical manufacturing to pharmaceutical drug production. The applications for naturally and artificially produced proteins include protein drugs and other pharmaceutical products, as biocatalysts in environmentally friendly chemical manufacturing, as enzymes for food processing purposes, and as an essential component in many biomedical devices. However, protein production suffers from many challenges, which include the cost of production, protein stability especially under harsh conditions, and recoverability and reusability of the proteins. The combination of two …

Go to article

Attachment, Vagal Tone, And Co-Regulation During Infancy, Jessica Chloe Hansen Dec 2014

Attachment, Vagal Tone, And Co-Regulation During Infancy, Jessica Chloe Hansen

Theses and Dissertations

This study examined the development of attachment as it relates to co-regulation and vagal tone over the second half of the first year of life. Links to infants' attachment and developmental status were also examined. Symmetrical and unilateral co-regulated patterns of interactions at 6 months demonstrated significant linkages with attachment. Developmental status did not show direct linkages with attachment. Direct links between vagal tone and attachment were also not identified. Correlations between co-regulation and vagal tone at the 6 month time point were identified. Findings suggest an important role of co-regulation as it relates to attachment development. Future studies may …

Go to article

Optimized Photogrammetric Network Design With Flight Path Planner For Uav-Based Terrain Surveillance, Ivan Yair Rojas Dec 2014

Optimized Photogrammetric Network Design With Flight Path Planner For Uav-Based Terrain Surveillance, Ivan Yair Rojas

Theses and Dissertations

This work demonstrates the use of genetic algorithms as a stochastic optimization technique for developing a camera network design and the flight path for photogrammetricapplications using Small Unmanned Aerial Vehicles. This study develops a Virtual Optimizer for Aerial Routes (VOAR) as a new photogrammetric mapping tool for acquisition of images to be used in 3D reconstruction. 3D point cloud models provide detailed information on infrastructure from places where human access may be difficult. This algorithm allows optimized flight paths to monitor infrastructure using GPS coordinates and optimized camera poses ensuring that the set of images captured is improved for 3D …

Go to article

Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor Dec 2014

Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor

Theses and Dissertations

The introduction and establishment of exotic species can profoundly alter ecosystems. Two exotic species drastically changing the landscape of deserts in western North America are Bromus tectorum L. and Bromus rubens L. Through the buildup of biomass and slow decomposition rates in deserts these two exotic annual grasses can alter fire regimes that change the plant and animal community dynamics in the ecosystems. To better understand the ecological mechanisms that could restrict or alter the patterns of invasive plant establishment we established a replicated full factorial experiment in the Great Basin and Mojave Desert. The combinations of factors being manipulated …

Go to article

The Interaction Of Aeolian And Fluvial Processes In Dry Washes On The Colorado Plateau, Usa, Beau Jensen Walker Dec 2014

The Interaction Of Aeolian And Fluvial Processes In Dry Washes On The Colorado Plateau, Usa, Beau Jensen Walker

Theses and Dissertations

In the past decade there has been a call for integrated studies that examine the interaction of fluvial and aeolian processes (Belnap et al., 2011; Bullard and Livingstone, 2002). In this study, we examined the role of land-use, weather, and soil type on the flux of aeolian material into dry washes on the Colorado Plateau in central Utah, USA, and western Colorado, USA. Our goal was to quantify the impact of individual deposition and erosion events by correlating weather and land-use data with a combination of measurement methods including dust collection via dust traps, GPS surveying, and close-range photogrammetry. Our …

Go to article

Fabrication, Characterization, Optimization And Application Development Of Novel Thin-Layer Chromatography Plates, Supriya Singh Kanyal Dec 2014

Fabrication, Characterization, Optimization And Application Development Of Novel Thin-Layer Chromatography Plates, Supriya Singh Kanyal

Theses and Dissertations

This dissertation describes advances in the microfabrication of thin layer chromatography (TLC) plates. These plates are prepared by the patterning of carbon nanotube (CNT) forests on substrates, followed by their infiltration with an inorganic material. This document is divided into ten sections or chapters. Chapter 1 reviews the basics of conventional TLC technology. This technology has not changed substantially in decades. This chapter also mentions some of the downsides of the conventional approach, which include unwanted interactions of the binder in the plates with the analytes, relatively slow development times, and only moderately high efficiencies. Chapter 2 focuses primarily on …

Go to article

Role Of Epistasis In Alzheimer's Disease Genetics, Mark T. Ebbert Dec 2014

Role Of Epistasis In Alzheimer's Disease Genetics, Mark T. Ebbert

Theses and Dissertations

Alzheimer's disease is a complex neurodegenerative disease whose basic etiology and genetic structure remains elusive, despite decades of intensive investigation. To date, the significant genetic markers identified have no obvious functional effects, and are unlikely to play a role in Alzheimer's disease etiology, themselves. These markers are likely linked to other genetic variations, rare or common. Regardless of what causal mutations are found, research has demonstrated that no single gene determines Alzheimer's disease development and progression. It is clear that Alzheimer's disease development and progression are based on a set of interactions between genes and environmental variables. This dissertation focuses …

Go to article

Targeted Sequencing Of Plant Genomes , Mark D. Huynh Dec 2014

Targeted Sequencing Of Plant Genomes , Mark D. Huynh

Theses and Dissertations

Next-generation sequencing (NGS) has revolutionized the field of genetics by providing a means for fast and relatively affordable sequencing. With the advancement of NGS, whole- genome sequencing (WGS) has become more commonplace. However, sequencing an entire genome is still not cost effective or even beneficial in all cases. In studies that do not require a whole-genome survey, WGS yields lower sequencing depth and sequencing of uninformative loci. Targeted sequencing utilizes the speed and low cost of NGS while providing deeper coverage for desired loci. This thesis applies targeted sequencing to the genomes of two different, non-model plants, Artemisia tridentate (sagebrush) …

Go to article

Extent Of Cysteine Modification Of Snap-25 In Vitro, Alex Mcgregor Dabell Dec 2014

Extent Of Cysteine Modification Of Snap-25 In Vitro, Alex Mcgregor Dabell

Theses and Dissertations

Exocytosis, the fusion of a vesicle to a cellular membrane, involves a protein named SNAP-25. This protein, containing two alpha helices connected with a linker region, is localized to the cell membrane via palmitic acids attached to the cysteine residues of its linker region in a process called palmitoylation. Are cysteine residues of the SNAP-25 linker region palmitoylated in an ordered manner and to a particular extent? The answer to this question may give insight into the regulated nature of exocytosis. While it is generally accepted that SNAP-25 must be palmitoylated in order to perform its exocytotic functions, the details …

Go to article

Nonlinear Modeling, Estimation And Predictive Control In Apmonitor, John Hedengren, Reza Asgharzadeh Shishavan, Kody M. Powell, Thomas F. Edgar Nov 2014

Nonlinear Modeling, Estimation And Predictive Control In Apmonitor, John Hedengren, Reza Asgharzadeh Shishavan, Kody M. Powell, Thomas F. Edgar

Faculty Publications

This paper describes nonlinear methods in model building, dynamic data reconciliation, and dynamic optimization that are inspired by researchers and motivated by industrial applications. A new formulation of the ℓ1-norm objective with a dead-band for estimation and control is presented. The dead-band in the objective is desirable for noise rejection, minimizing unnecessary parameter adjustments and movement of manipulated variables. As a motivating example, a small and well-known nonlinear multivariable level control problem is detailed that has a number of common characteristics to larger controllers seen in practice. The methods are also demonstrated on larger problems to reveal algorithmic …

Go to article

First Record Of Leucism In The Genus Peromyscus (Mammalia: Rodentia), Issac Camargo, Evelyn Rios, Cristian Cornejo-Latorre, Sergio Ticul Álvarez-Castañeda Nov 2014

First Record Of Leucism In The Genus Peromyscus (Mammalia: Rodentia), Issac Camargo, Evelyn Rios, Cristian Cornejo-Latorre, Sergio Ticul Álvarez-Castañeda

Western North American Naturalist

Leucism is a partial hypopigmentary congenital disorder previously recorded in several species of mammals. This abnormal coloration is unusual in the wild. In August 2013, in the Baja California State, México, we collected two Peromyscus fraterculus (one female and one male) exhibiting leucism. Leucism has not been reported before ingenus Peromyscus, therefore, we documented the first known record. Leucism is a reflex of low levels of genetic diversity in natural populations. It may increase selective pressure on individuals.

Go to article

Estimating The Ages Of Mountain Sucker Catostomus Platyrhynchus From The Black Hills: Precision, Maturation, And Growth, Jason J. Breeggemann, Cari-Ann Hayer, Jacob Krause, Luke D. Schultz, Katie N. Bertrand, Brian D. S. Graeb Nov 2014

Estimating The Ages Of Mountain Sucker Catostomus Platyrhynchus From The Black Hills: Precision, Maturation, And Growth, Jason J. Breeggemann, Cari-Ann Hayer, Jacob Krause, Luke D. Schultz, Katie N. Bertrand, Brian D. S. Graeb

Western North American Naturalist

Mountain Sucker Catostomus platyrhynchus is considered secure across its range, it has been declining in parts of its range, and is listed as a species of greatest conservation need in South Dakota. To our knowledge, no research has identified which calcified structure yields the most precise age estimates for Mountain Sucker and little is known about Mountain Sucker population dynamics. We compared scales, sectioned fin rays, whole otoliths, and polished otoliths to identify which structure provided the most precise age estimates for Mountain Sucker in the Black Hills of South Dakota. Additionally, we quantified recruitment, growth, age and size at …

Go to article

Home-Range Size And Subadult Dispersal Of Black Bears In The Cascade Range Of Western Oregon, Dave Immell, Dewaine H. Jackson, Margaret C. Boulay Nov 2014

Home-Range Size And Subadult Dispersal Of Black Bears In The Cascade Range Of Western Oregon, Dave Immell, Dewaine H. Jackson, Margaret C. Boulay

Western North American Naturalist

Knowledge of home range size and subadult dispersal activity of North American black bears is essential for understanding the complexity of how bears interact within populations and the environment. During 1993-98, we monitored 96 radiocollared black bears (Ursus americanus) in the Cascade Range of western Oregon to estimate home range and dispersal movements. Composite fixed-kernel home ranges were calculated for 37 bears. Mean home range size differed between sexes (189.7 km2 for males and 33.6 km2 for females); however, there was no difference between subadult and adult male or subadult and adult female mean home range …

Go to article

Rediscovered Populations Of The Idaho Point-Headed Grasshopper, Acrolophitus Pulchellus (Bruner), 1890 (Orthoptera: Acrididae), Beth A. Waterbury Nov 2014

Rediscovered Populations Of The Idaho Point-Headed Grasshopper, Acrolophitus Pulchellus (Bruner), 1890 (Orthoptera: Acrididae), Beth A. Waterbury

Western North American Naturalist

The Idaho point-headed grasshopper, Acrolophitus pulchellus, is a rare endemic of the Sinks Drainages of east-central Idaho. Past collections were infrequent and found few specimens. Searches in 1993 failed to find specimens, leading to speculaton that A. pulchellus was extinct. I report rediscovered populations of A. pulchellus based on 55 capture records (10 collected); describe distribution, habitat, morphological, and life history information; and present the first photos of live adult specimens.

Go to article

New Vascular Plant Floristic Records For The Dakotas, Karen Meyer Walker, Ashley Pemberton, Tyler Grassrope, Kayla Gravatt, Sunshine Claymore, Wendy L. Applequist Nov 2014

New Vascular Plant Floristic Records For The Dakotas, Karen Meyer Walker, Ashley Pemberton, Tyler Grassrope, Kayla Gravatt, Sunshine Claymore, Wendy L. Applequist

Western North American Naturalist

Recent collections of vascular plants on the Crow Creek Indian Reservation in central South Dakota include 64 new county records for Hughes County, 72 for Buffalo County, and 1 for Hyde County. Additionally, 2 new county records are reported for Sioux County in southern North Dakota.


Las recientes colectas de plantas vasculares en la Reserva Indie Crow Creek en el centro de Dakota del Sur incluyen: 64 nuevos registros en el Condado Hughes, 72 en el Condado Buffalo y uno en el Condado Hyde. Además, se reportaron dos nuevos registros en al Condado Sioux, en el sur de Dakota del …

Go to article

Front Matter, Vol. 74 No. 3 Nov 2014

Front Matter, Vol. 74 No. 3

Western North American Naturalist

No abstract provided.

Go to article

End Matter, Vol. 74 No. 3 Nov 2014

End Matter, Vol. 74 No. 3

Western North American Naturalist

No abstract provided.

Go to article

Demographic Monitoring And Population Viability Analysis Of Two Rare Beardtongues From The Uinta Basin, Rebecca M. Mccaffery, Rita Reisor, Kathryn Irvine, Jessi Brunson Nov 2014

Demographic Monitoring And Population Viability Analysis Of Two Rare Beardtongues From The Uinta Basin, Rebecca M. Mccaffery, Rita Reisor, Kathryn Irvine, Jessi Brunson

Western North American Naturalist

Energy development, in combination with other environmental stressors, poses a persistent threat to rare species endemic to the energy-producing regions of the Western United States. Demographic analyses of monitored populations can provide key information on the natural dynamics of threatened plant and animal populations, and how they might be affected by ongoing and future development. In the Uinta Basin in Utah and Colorado, Graham’s beardtongue (Penstemon grahamii) and White River beardtongue (Penstemon scariosus var. albifluvis) are two rare endemic wildflowers that persist on oil shale habitats heavily impacted by current energy exploration and development, and slated …

Go to article

The Plecoptera And Trichoptera Of The Arctic North Slope Of Alaska, Michael R. Kendrick, Alexander D. Huryn Nov 2014

The Plecoptera And Trichoptera Of The Arctic North Slope Of Alaska, Michael R. Kendrick, Alexander D. Huryn

Western North American Naturalist

The Arctic is currently experiencing changes in climate more rapid than any other biome. This warming trend has resulted in significant abiotic changes to the seasonal patterns of freshwater ecosystems. Thorough inventories of freshwater insect communities are required to provide benchmarks allowing for the detection of range shifts in response to a warming climate. While statewide studies have been conducted for Trichoptera and Plecoptera, species accounts for these orders in Arctic Alaska have received relatively little attention. We surveyed Plecoptera and Trichoptera of Alaska’s Arctic North Slope at a variety of habitat types over an 11 year period. We document …

Go to article

Influence Of Nonnative And Native Ungulate Biomass And Seasonal Precipitation On The Vegetation Production In A Great Basin Ecosystem, Linda C. Zeigenfuss, Kathryn A. Schoenecker, Jason I. Ransom, Drew A. Ignizio, Tracy Mask Nov 2014

Influence Of Nonnative And Native Ungulate Biomass And Seasonal Precipitation On The Vegetation Production In A Great Basin Ecosystem, Linda C. Zeigenfuss, Kathryn A. Schoenecker, Jason I. Ransom, Drew A. Ignizio, Tracy Mask

Western North American Naturalist

The negative effects of equid grazers in semi-arid ecosystems of the American West has been considered to be disproportionate to the influence of native ungulates in these systems because of their large body size, hoof shape, and short history on the landscape relative to native grazers. Tools which can model the degree of influence of various grazers in an ecosystem and separate these effects from those caused by other variables (climate, anthropomorphic disturbances) can be useful to managers in determining location of non-native grazer impacts and assessing the effect of management actions targeted at different grazer populations. We used remotely …

Go to article

First Prev Next Last