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

Digital Commons Network™

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

Theses and Dissertations

Theses/Dissertations

2017

Discipline
Institution
Keyword
File Type

Articles 61 - 90 of 3666

Full-Text Articles in Entire DC Network

Portable X-Ray Fluorescence Spectrometer Analysis Of The Pylos Linear B Tablets, Billy B. Wilemon Dec 2017

Portable X-Ray Fluorescence Spectrometer Analysis Of The Pylos Linear B Tablets, Billy B. Wilemon

Theses and Dissertations

This thesis investigates similarities and differences in the chemistry of the Linear B clay tablets and sealings found at the Palace of Nestor in Pylos, located in the western Peloponnese, Greece. Their chemistry provides clues regarding the flow of material goods in and out of the palace and therefore to the degree of centralization of the political-economy. Over a thousand 3,000 year-old clay tablets and sealings currently housed at the National Archaeological Museum in Athens were analyzed using a pXRF over the course of the summers of 2015 and 2016. The chemical compositions were analyzed statistically. Results of the study …

Go to article

A Simulation Of Lfm Pulse-Doppler Radar And An Application Of Cohen-Daubechies-Feauveau Wavelets In Cfar Detection, Aaron Joshua Wright Dec 2017

A Simulation Of Lfm Pulse-Doppler Radar And An Application Of Cohen-Daubechies-Feauveau Wavelets In Cfar Detection, Aaron Joshua Wright

Theses and Dissertations

This thesis presents a simulation of an LFM pulse-Doppler radar for surface-to-air applications and compares the performance of multiple CFAR detectors in processing the resulting range-Doppler maps. Each CFAR detector is reviewed and simulated. Their effectiveness in reducing target masking is analyzed. In addition, a new CFAR detector, the RDWT-CA-CFAR detector, is developed that uses the CDF 5/3 wavelet to decompose the range-data of the range-Doppler map along the range dimension and filter the target data from the reference cells, as a means to reduce or eliminate target masking. The QccPack library is used to perform RDWT functions. It is …

Go to article

Explaining Mental Health Stigma Through Controllability, Just World Beliefs, And Social Dominance Orientation, Katherine F. Peterson Dec 2017

Explaining Mental Health Stigma Through Controllability, Just World Beliefs, And Social Dominance Orientation, Katherine F. Peterson

Theses and Dissertations

Mental illness carries a pervasive stigma. Research uncovered several theories to explain stigma, including the Attribution Theory, the Biological Model, Belief in a Just World (BJW), and Social Dominance Orientation (SDO). Previous research identified a mediational pathway in which BJW influenced SDO, and where SDO predicted stigmatizing beliefs and intent to discriminate. There is a lack of research examining BJW and SDO from within the framework of mental illness controllability. This study attempted to fill in the gap within stigma literature by examining if perceived mental illness controllability influences the BJW-SDO- Stigma model. Analyses failed to replicate the previously found …

Go to article

Factors Influencing The Use Of Consulting Foresters By Non-Industrial Private Forest Landowners In Mississippi, Sagar Godar Chhetri Dec 2017

Factors Influencing The Use Of Consulting Foresters By Non-Industrial Private Forest Landowners In Mississippi, Sagar Godar Chhetri

Theses and Dissertations

This study describes landowners’ willingness to hire consulting foresters and compares forest management expenses between the 1990s (1995-1997) and 2015. Two thousand and ten Mississippi non-industrial private forest (NIPF) landowners were selected randomly from a tax roll mail list maintained by Mississippi State University. Participants were surveyed to identify the characteristics of those landowners willing to hire consultants and compared the landowners’ participation in forestry-related activities during the 1990s and 2015. Results indicated three fourth of the survey participants were not willing to use a consultant to manage their forest land. However, consultant fees have increased from the 1990s to …

Go to article

Feasibility And Marketing Channels Of A Smartphone Application That Brings Nondestructive Techniques To Job Sites, Songyi Han Dec 2017

Feasibility And Marketing Channels Of A Smartphone Application That Brings Nondestructive Techniques To Job Sites, Songyi Han

Theses and Dissertations

This work conducted market research on the use of smartphones and smartphone applications in the forest products industry and academia. This research also attempted to project how likely the industry would be to use an app that measures stiffness of wood. After the review of scholarly literature and existing apps, data was collected via an online survey. Participants were individuals who work with wood or wood-based products. Out of 1,221 invitations, 311 were returned at the response rate of 27.2 percent. Data was analyzed using SPSS statistics. Nearly all of the respondents (95.7%) had smartphones, and over half of them …

Go to article

Finite Element Study On The Influence Of Bone-Implant Interface Condition On Femoral Fracture After Cementless Total Hip Replacement, Caleb Onuh Yenusah Dec 2017

Finite Element Study On The Influence Of Bone-Implant Interface Condition On Femoral Fracture After Cementless Total Hip Replacement, Caleb Onuh Yenusah

Theses and Dissertations

Finite element analysis was performed on an implanted femur, using loads of daily living activities, performed by total hip replacement patients. A probabilistic bone fatigue failure model was utilized to analysis the risk of post-operative femoral fracture in different patient groups, depending on bone fatigue strength for young and elderly patients, and activity levels for normal and active patients. Different bone-implant interface conditions were considered: after surgery, osseointegrated, fibrous tissue covering, and loose. For young patients, the probability of failure is less than 4% for all cases. While in elderly patients, high of 28.2% and 57.9% are reported for normal …

Go to article

Formulation Of Whey Protein Stabilized Multilayered Microemulsion And Nanoemulsion Systems With Hyperoxidative Curcumin, Soma Mukherjee Dec 2017

Formulation Of Whey Protein Stabilized Multilayered Microemulsion And Nanoemulsion Systems With Hyperoxidative Curcumin, Soma Mukherjee

Theses and Dissertations

A primary emulsion with whey protein isolate (WPI) and hexanoic acid was prepared, and chitosan (Ch) (0.01%, 0.02%, and 0.03%) was added to evaluate its impact on particle size distribution of the emulsion. NaCl (0, 20, 40, and 80 mM) was added to increase ionic interactions to stabilize the multilayer emulsion. Lecithin (0.5%, 1%, 2%, 3 %, w/v) was mixed with the primary emulsion in order to form a multilayer, and casein hydrolysate (CH) was used to stabilize the tertiary emulsion system without the use of NaCl for 28 d at 4 °C. Stable O/W nanoemulsions were generated for use …

Go to article

Genome Maintenance By Selenoprotein H In The Nucleolus, Li Zhang Dec 2017

Genome Maintenance By Selenoprotein H In The Nucleolus, Li Zhang

Theses and Dissertations

Selenoprotein H (SELENOH) is a nucleolar oxidoreductase with DNA binding properties whose function is not well understood. To determine the functional and physiological roles of SELENOH, a knockout of SELENOH was generated in cell lines using CRISPR/Cas9-mediated genomic deletion and in mice by targeted disruption. Based on the sequenced genome, the results of deduced protein sequences indicated various forms of mutants in the CRISPR/Cas9-mediated knockout, including a frame-shift by aberrant splicing and truncated SELENOH by early termination of the translation process. Loss of SELENOH in HeLa cells induced slow cell proliferation, the formation of giant multinucleated cells, accumulation of unrepaired …

Go to article

Differences In Survival Of Heat Stress Adapted Cells Of Listeria Monocytogenes Egd (Bug600) In Disinfectants And Essential Oils, Amruta Udaysinh Jadhav Dec 2017

Differences In Survival Of Heat Stress Adapted Cells Of Listeria Monocytogenes Egd (Bug600) In Disinfectants And Essential Oils, Amruta Udaysinh Jadhav

Theses and Dissertations

The objective of this study was to investigate the differences in survival of L. monocytogenes EGD (Bug600) (serotype 1/2a) in various disinfectants and essential oils after sublethal heat stress at 48°C for 60 min. The survival of heat stressed L. monocytogenes cells was decreased in lethal acid (HCl or H3PO4 pH 2.5), lethal oxidative stress (H2O2 1000 ppm) and lethal quaternary ammonium compounds (QAC 2.5-3.5 ppm) compared to non-stressed control cells. By contrast, the survival of heat stressed L. monocytogenes cells was higher in lethal alkali (NaOH or KOH pH 12) than the control cells. Also, the survival of heat …

Go to article

Ecology And Conservation Of Bird Assemblages In Native And Afforested Environments In The Northern Campos Grasslands Of Uruguay, Juan Andrés Martínez Lanfranco Dec 2017

Ecology And Conservation Of Bird Assemblages In Native And Afforested Environments In The Northern Campos Grasslands Of Uruguay, Juan Andrés Martínez Lanfranco

Theses and Dissertations

Commercial forestry has expanded across the Rio de la Plata Grasslands (RPG) of South America in recent decades. I conducted a resource-use based study on bird communities during the 2013-2014 austral breeding season in northern Uruguay. I assessed relationships between habitat types and bird abundance as a function of vegetation structure. To compare avian responses to treatments, I included native environments, pine and eucalyptus plantations of different ages and thinning regimes. I detected differences in species richness and composition and species-specific responses in abundance along structural gradients sampled. Although poorer in species than native habitat types, tree plantations were extensively …

Go to article

Characterization Of Type Vi Secretion System In Edwardsiella Ictaluri, Safak Kalindamar Dec 2017

Characterization Of Type Vi Secretion System In Edwardsiella Ictaluri, Safak Kalindamar

Theses and Dissertations

Edwardsiella ictaluri causes enteric septicemia of catfish (ESC), which is one of the most important bacterial diseases causing significant economic losses in the US catfish industry. Understanding the virulence mechanisms of E. ictaluri plays a vital role to develop preventives, such as vaccines for the disease. Therefore, further research is necessary to discover the new virulence mechanisms of this pathogen. The long-term goal of our group is to determine the mechanism of E. ictaluri pathogenesis and to develop effective live attenuated vaccines against ESC. The overall goal of this project is to understand the role of Type 6 secretion system …

Go to article

Control Of Görtler Vortices In High-Speed Boundary Layers, Radwa Alaziz Dec 2017

Control Of Görtler Vortices In High-Speed Boundary Layers, Radwa Alaziz

Theses and Dissertations

Görtler vortices develop in boundary layer flows over concave surfaces due to the imbalance between centrifugal forces and the wall-normal pressure gradient. These vortices can be efficient precursors to transition in boundary layers exposed to free-stream disturbance or surface non-uniformities, because they can alter the mean flow causing the laminar flow to breakdown into turbulence. In this thesis, a control technique aimed at reducing the energy associated with Görtler vortices that develop in supersonic boundary layers is introduced and tested. The control algorithm is based on distributed blowing and suction, with sensors placed either in the flow or at the …

Go to article

Occurrence Of Bornean Mammals In Two Commercial Forest Reserves And Characteristics That Influence Their Detectability, Seth Timothy Wong Dec 2017

Occurrence Of Bornean Mammals In Two Commercial Forest Reserves And Characteristics That Influence Their Detectability, Seth Timothy Wong

Theses and Dissertations

The Southeast Asian island of Borneo boasts an incredible diversity of terrestrial mammals which is threatened by habitat loss. Understanding the abundance and distribution of these species is essential for conservation and management. We assessed the occurrence of terrestrial mammals within two commercial forest reserves in Sabah, Malaysian Borneo. In particular, we investigated the habitat associations of the Sunda stink-badger, whose patchy distribution is not well understood. To improve detection probability and precision of model parameters, we deployed 2 camera-traps at sample stations. Our results showed that Sunda stink-badgers are likely dietary and habitat generalists, that may benefit from forest …

Go to article

Effect Of Water Temperature, Angling Time, And Dissolved Oxygen Concentration On The Survival Of Angled And Tournament-Handled Largemouth Bass, Kevin Randy Keretz Dec 2017

Effect Of Water Temperature, Angling Time, And Dissolved Oxygen Concentration On The Survival Of Angled And Tournament-Handled Largemouth Bass, Kevin Randy Keretz

Theses and Dissertations

Largemouth Bass Micropterus salmoides is the most sought after species by recreational anglers in the United States. Survival of angled and tournament-handled Largemouth Bass is related to numerous factors; however, the independent effects of water temperature, angling time, and live well dissolved oxygen concentration on survival have not been measured. Survival was evaluated in simulated catch and release and tournament trials over the range of temperatures encountered by Largemouth Bass anglers (17-33°C) while also testing independent effects of angling time, live well temperature, and live well dissolved oxygen treatments. Caught-and-released Largemouth Bass experienced 100% survival at temperatures ≤33°C after 1 …

Go to article

Effects Of Temperature And Hydrology On Growth And Recruitment Of Shovelnose Sturgeon In The Lower Mississippi River, Jared Mccarty Porter Dec 2017

Effects Of Temperature And Hydrology On Growth And Recruitment Of Shovelnose Sturgeon In The Lower Mississippi River, Jared Mccarty Porter

Theses and Dissertations

I evaluated the effects of thermal and hydrologic conditions on growth and recruitment of Shovelnose Sturgeon (Scaphirhynchus platorynchus) in the lower Mississippi River and assessed mortality. Duration of water temperatures 12-24°C had a positive influence and temperatures below 11°C had a negative influence on annual growth. Duration of water temperatures above 28°C, duration of floodplain inundation, duration of low water, and minimum and maximum river stage did not influence annual growth. Duration of water temperatures 18-20°C and 18-24°C had a positive influence on recruitment, and duration of temperatures at and below 10°C had a negative influence on recruitment. Duration of …

Go to article

Efficacy Of Novel Pyridinium Oximes In Preventing Neural Damage, Charles Andrew Leach Dec 2017

Efficacy Of Novel Pyridinium Oximes In Preventing Neural Damage, Charles Andrew Leach

Theses and Dissertations

Organophosphates are neurotoxic compounds that inhibit acetylcholinesterase producing excess cholinergic stimulation. This produces various toxic signs including excitotoxic neuronal damage. Oximes can be used as a treatment for organophosphate poisoning by reactivating inhibited acetylcholinesterase. Traditional oximes do not penetrate the blood-brain barrier, limiting protection of the central nervous system. Novel, brain-penetrating oximes have the potential to protect the brain from organophosphate induced damage. Adult male rats were used to examine the ability of model organophosphates to produce neuropathology and the ability of novel oximes to prevent this damage. Additionally, adult male rats were used to examine changes in gene expression …

Go to article

Hypervelocity Impact Of Spherical Aluminum 2017-T4 Projectiles On Aluminum 6061-T6 Multi-Layered Sheets, Michael Deivi Marroquin Salvador Dec 2017

Hypervelocity Impact Of Spherical Aluminum 2017-T4 Projectiles On Aluminum 6061-T6 Multi-Layered Sheets, Michael Deivi Marroquin Salvador

Theses and Dissertations

With the growing threat of orbital debris impacts to space structures, the development of space shielding concepts has been a critical research topic. In this study, numerical simulations of the hypervelocity impact response of stacked aluminum 6061-T6 sheets were performed to assess the effects of layering on penetration resistance. This work was initially motivated by set of experimental tests where a stack of four aluminum sheets of equal thickness was observed to have a higher hypervelocity ballistic resistance than a monolithic aluminum sheet with the same total thickness. A set of smoothed particle hydrodynamic simulations predicted a 40% increase in …

Go to article

Spatiotemporal Variation In Space Use By Eastern Wild Turkeys In Mississippi, Ryo Ogawa Dec 2017

Spatiotemporal Variation In Space Use By Eastern Wild Turkeys In Mississippi, Ryo Ogawa

Theses and Dissertations

Spatiotemporal variation in animal space use is critical for understanding how individual animals respond to changes in resource availability across space and time. My study was aimed to: 1) determine functional responses of habitat selection by eastern wild turkeys (Meleagris gallopavo silvestris) across 7 study sites in Mississippi; and 2) determine the effect of temporal vegetation variation on order-II habitat selection by wild turkeys over 12 years. I developed resource selection functions using radio telemetry location data. Individual-specific coefficients of order-III habitat selection for forest were related inversely to forest availability in meta-regressions. Yearly coefficients of order-II habitat selection for …

Go to article

Stratigraphic Variability Of The Desmoinesian Marmaton Group Across The Lips Fault System In The Texas Panhandle Granite Wash, Southern Anadarko Basin, Patrick Daniel Jordan Dec 2017

Stratigraphic Variability Of The Desmoinesian Marmaton Group Across The Lips Fault System In The Texas Panhandle Granite Wash, Southern Anadarko Basin, Patrick Daniel Jordan

Theses and Dissertations

The Desmoinesian Marmaton Group, along the southern portion of the Anadarko Basin in the Granite Wash, comprises over 2,000 feet of stacked tight sandstones and conglomerates, containing unconventional reservoirs. Uncertainty around facies variability and lateral continuity of these reservoirs represents challenges to accurate reservoir characterization due to laterally restricted submarine fan systems, and mountainront faulting. This study examines 206 wire-line well-log suites and nine ice-house flooding surfaces across an 810-square mile study area to frame fine-scale sequences, track facies changes, and estimate fault timing and duration. This high-resolution stratigraphic framework comprises a hierarchy of cycles: one third-order, three fourth-order, and …

Go to article

Student Loan Debt For Community College Transfer Students And How Debt Information Letters Impact Future Borrowing Decisions, Kenneth Paul Mckinney Dec 2017

Student Loan Debt For Community College Transfer Students And How Debt Information Letters Impact Future Borrowing Decisions, Kenneth Paul Mckinney

Theses and Dissertations

There has been a proliferation of student loan debt over the past decade. The indebtedness that students incur while attending college reduces their discretionary income once they enter repayment after graduation. For graduates, there is an opportunity cost along with personal and professional life decisions being made based on this debt. For example, some students are choosing the enter the workforce after obtaining their undergraduate degree instead of pursuing a graduate degree. The purpose of this study was to examine the decisions that currently enrolled undergraduate students are making about obtaining student loans based on information supplied to them about …

Go to article

Student Perceptions Of The Impact Of Participation In Community College Mental Health Counseling On Retention, Graduation, And Transfer, Matt Jordan Quin Dec 2017

Student Perceptions Of The Impact Of Participation In Community College Mental Health Counseling On Retention, Graduation, And Transfer, Matt Jordan Quin

Theses and Dissertations

This dissertation examined community college transfer students’ perceptions of how mental health concerns interfere with academics, the ability to stay in school, graduate, and transfer to a 4-year university. The study also examined if community college transfer students perceive that mental health counseling improves their ability to stay in college, graduate from community college, and overcome barriers that interfere with the ability to transfer to a 4-year university. The study employed descriptive statistics and one-way between subjects ANOVAs to examine the effects of demographic characteristics and presenting mental health concerns on the ability to remain in community college, graduate from …

Go to article

Improved Heuristic Search Algorithms For Decision-Theoretic Planning, Ibrahim Abdoulahi Dec 2017

Improved Heuristic Search Algorithms For Decision-Theoretic Planning, Ibrahim Abdoulahi

Theses and Dissertations

A large class of practical planning problems that require reasoning about uncertain outcomes, as well as tradeoffs among competing goals, can be modeled as Markov decision processes (MDPs). This model has been studied for over 60 years, and has many applications that range from stochastic inventory control and supply-chain planning, to probabilistic model checking and robotic control. Standard dynamic programming algorithms solve these problems for the entire state space. A more efficient heuristic search approach focuses computation on solving these problems for the relevant part of the state space only, given a start state, and using heuristics to identify irrelevant …

Go to article

In Vitro And In Vivo Effects Of An Encapsulated Butyric Acid And A Lactic Acid Producing Bacteria Used Alone Or In Combination, Dana Kristen Dittoe Dec 2017

In Vitro And In Vivo Effects Of An Encapsulated Butyric Acid And A Lactic Acid Producing Bacteria Used Alone Or In Combination, Dana Kristen Dittoe

Theses and Dissertations

Lactic acid producing bacteria (LAB) and organic acids have been proposed as effective alternatives to antibiotics, however there is limited literature concerning their combination. Thus, the objective of this thesis was to investigate the effects of LAB, encapsulated butyric acid (EBA), and their combination. Under challenged conditions, the in vitro study demonstrated that both EBA and LAB were capable of reducing pathogen proliferation over time, with greater efficacy at lower initial concentration. However, EBA demonstrated a greater effectiveness on pathogen reduction. Under challenged conditions, the results of the in vivo study indicated that birds fed LAB performed comparatively to that …

Go to article

Introducing New Energy Dissipation Mechanisms For Steel Fiber Reinforcement In Ultra-High Performance Concrete, Dylan Andrew Scott Dec 2017

Introducing New Energy Dissipation Mechanisms For Steel Fiber Reinforcement In Ultra-High Performance Concrete, Dylan Andrew Scott

Theses and Dissertations

By adding annealed plain carbon steel fibers and stainless steel fibers into Ultra-High Performance Concrete (UHPC), we have increased UHPC’s toughness through optimized thermal processing and alloy selection of steel fiber reinforcements. Currently, steel fiber reinforcements used in UHPCs are extremely brittle and have limited energy dissipation mainly through debonding due to matrix crumbling with some pullout. Implementing optimized heat treatments and selecting proper alternative alloys can drastically improve the post-yield carrying capacity of UHPCs for static and dynamic applications through plastic deformations, phase transformations, and fiber pullout. By using a phase transformable stainless steel, the ultimate flexural strength increased …

Go to article

Investigating Extra Hepatic Steroid And Eicosanoid Metabolizing Enzymes In Cattle, Megan Pauline Theresa Owen Dec 2017

Investigating Extra Hepatic Steroid And Eicosanoid Metabolizing Enzymes In Cattle, Megan Pauline Theresa Owen

Theses and Dissertations

Steroid and eicosanoid metabolism occurs in two phases and primarily within hepatic tissues, but localized metabolism has been examined in several extra-hepatic tissues in humans and rodents. Phase I of metabolism is performed by Cytochrome P450s (CYP) that add hydroxyl groups to the carbon ring structure which is further metabolized by phase II UDP-glucuronosyltransferase (UGT). The overall objectives of the following experiments were to: 1) determine the amount of extra-hepatic steroid metabolism within reproductive tissues of cattle across the estrous cycle; 2) determine the amount of extra-hepatic steroid metabolism and an oxylipin profile within reproductive tissues of cattle based on …

Go to article

Investigation Of The Directed Self-Assembly Process In Bacteriophage Virus Structures Using The Discrete Element Method, David Peter Mcinnis Dec 2017

Investigation Of The Directed Self-Assembly Process In Bacteriophage Virus Structures Using The Discrete Element Method, David Peter Mcinnis

Theses and Dissertations

Current researchers have looked to nature to learn how self-assembly processes occur. By understanding the self-assembly process, designers can begin to build strong structural materials that are extremely light weight. The discrete element modeling method was used to gain a better understanding of the directed self-assembly of M13 bacteriophage. This model was parameterized from molecular dynamics simulations at the nanometer scale. Three types of functionalized bacteriophage were studied: Wild-type, 4E, and CLP8. Results showed that Wild-type phage are attracted in a head-to-tail orientation, but repelled in head-to-head orientation. The 4E bacteriophage behaved similarly with a stronger bond in the head-to-tail …

Go to article

Leadership Frames In Comprehensive Community Colleges: Implications For The Market-Responsive College, David Layne Campbell Dec 2017

Leadership Frames In Comprehensive Community Colleges: Implications For The Market-Responsive College, David Layne Campbell

Theses and Dissertations

Market-responsive college leaders are challenged to navigate external relationships with business and industry, government officials, and community leaders, as well as the resulting pressures of multiple missions of the comprehensive community college. The leaders are faced with three predominant issues involving the market-responsive college and its relationship to the overall comprehensive college. These issues include: (a) its relationship to the transfer role, (b) difficulty of defining and measuring its success, and (c) its placement within the organization. Bolman and Deal’s (2013) leadership frames provide a model to understand how framing by market-responsive college leaders influences their organizations. A qualitative case …

Go to article

Listeria Monocytogenes Response To Sublethal Sodium Hypochlorite Induced Oxidative Stress On Its Biofilm Forming Ability And Antibiotic Resistance, Mohit Bansal Dec 2017

Listeria Monocytogenes Response To Sublethal Sodium Hypochlorite Induced Oxidative Stress On Its Biofilm Forming Ability And Antibiotic Resistance, Mohit Bansal

Theses and Dissertations

Listeria monocytogenes response to oxidative stress by sublethal sodium hypochlorite was investigated in this study. Continuous exposure of sublethal chlorine influenced biofilm formation and stress adaptation (homologous and heterologous) in L. monocytogenes. The biofilm forming ability of oxidative stress adapted and control cells were investigated on polystyrene surface at 22°C and 37°C. The oxidative stress adapted cells were found to form less biofilm in the presence of chlorine (p < 0.10) when compared to non-treated control cells at both the temperatures. In addition, the biofilm forming ability of L. monocytogenes was reduced significantly at higher sublethal chlorine concentrations (p < 0.10). In conclusion, oxidative stress adapted L. monocytogenes has developed tolerance to chlorine and some of the antibiotics. However, oxidative stress those cells did demonstrate an antibiofilm effect. This demonstrates that oxidative stress reduces L. monocytogenes biofilm formation but can also increase antibiotic resistance.

Go to article

Long-Term Effects Of Post-Fire Forest Structure On Understory Vegetation In Larch Forests Of The Siberian Arctic, Homero Pena Dec 2017

Long-Term Effects Of Post-Fire Forest Structure On Understory Vegetation In Larch Forests Of The Siberian Arctic, Homero Pena

Theses and Dissertations

Climate warming is increasing fire severity in boreal forests and can alter forest structure and carbon (C) dynamics in Cajander larch (Larix cajanderi) forests of Siberia, which occur over C and ice-rich yedoma permafrost. Altered forest structure may impact understory vegetation through changing canopy cover, permafrost thaw depth, and soil temperatures. The primary objective of this study was to assess the long-term impacts of fire-driven changes in tree density on understory composition, diversity, and C pools and the underlying soil organic layer (SOL). Shrubs dominated low density stands, likely from reduced canopy cover and thaw depth, while mosses dominated high …

Go to article

Micromechanical Modeling Of Shear Banding In Granular Media, Charles Clayton Goodman Dec 2017

Micromechanical Modeling Of Shear Banding In Granular Media, Charles Clayton Goodman

Theses and Dissertations

Shear banding is a commonly observed yet complex form of instability in granular media by which the deformation is localized in a narrow zone along a certain path. The aim of this study is to investigate the micromechanics of shear banding using the discrete element method (DEM). For this purpose, a model was developed and calibrated to simulate the macroscale behavior of sand under plane strain conditions. Upon validation against laboratory experiments, two types of confining boundaries, displacement- and force-controlled, were examined to study the kinematics of shear bands. A constant volume test was then used to investigate the evolution …

Go to article

First Prev Next Last