Digital Commons Network^™

Bisexuality And Motherhood: An Investigation Of Psychological Distress, Parenting Efficacy, And Self Esteem Through Identity Theory, Laurin B. Roberts

Psychology Theses & Dissertations

Bisexual individuals are more likely to be parenting as compared to other sexual minority individuals, however a review of the current research on sexual minority parenting and families demonstrates a limited understanding of the experiences unique to this population. Furthermore, the socialization of parenthood as both a heterosexual practice, and one that is intertwined with womanhood suggests bisexual mothers may encounter unique challenges and experiences in negotiating these two identities. Therefore the current study seeks to expand upon the literature with a primary aim of understanding the relationship between bisexuality and motherhood identities, psychological distress, parenting efficacy, and self-esteem from …

Design And Implementation Of An Artificial Neural Network Controller For Quadrotor Flight In Confined Environment, Ahmed Mekky

Mechanical & Aerospace Engineering Theses & Dissertations

Quadrotors offer practical solutions for many applications, such as emergency rescue, surveillance, military operations, videography and many more. For this reason, they have recently attracted the attention of research and industry. Even though they have been intensively studied, quadrotors still suffer from some challenges that limit their use, such as trajectory measurement, attitude estimation, obstacle avoidance, safety precautions, and land cybersecurity. One major problem is flying in a confined environment, such as closed buildings and tunnels, where the aerodynamics around the quadrotor are affected by close proximity objects, which result in tracking performance deterioration, and sometimes instability. To address this …

Assessing Phytoplankton Nutritional Status And Potential Impact Of Wet Deposition In Seasonally Oligotrophic Waters Of The Mid-Atlantic Bight, P. N. Sedwick, P. W. Bernhardt, M. R. Mulholland, R. G. Najjar, L. M. Blumen, B. M. Sohst, C. Sookhdeo, Brittany Widner

OES Faculty Publications

To assess phytoplankton nutritional status in seasonally oligotrophic waters of the southern Mid-Atlantic Bight, and the potential for rain to stimulate primary production in this region during summer, shipboard bioassay experiments were performed using natural seawater and phytoplankton collected north and south of the Gulf Stream. Bioassay treatments comprised iron, nitrate, iron + nitrate, iron + nitrate + phosphate, and rainwater. Phytoplankton growth was inferred from changes in chlorophyll a, inorganic nitrogen, and carbon-13 uptake, relative to unamended control treatments. Results indicated the greatest growth stimulation by iron + nitrate + phosphate, intermediate growth stimulation by rainwater, modest growth …

A Comparative Analysis Of Holographic, 3d-Printed, And Computer-Generated Models: Implications For Engineering Technology Students' Spatial Visualization Ability, Petros J. Katsioloudis, Mildred V. Jones

STEMPS Faculty Publications

A number of studies indicate that the use of holographic displays can influence spatial visualization ability; however, research provides inconsistent results. Considering this, a quasi-experimental study was conducted to identify the existence of statistically significant effects on sectional view drawing ability due to the impacts of holographic displays. In particular, the study compared the use of three different types of displays: 3D printed model, computer generated model, and holographic model to determine whether a significant difference exists towards sectional view drawing ability, among engineering technology students. According to the results of this study, it is suggested that the impact of …

Proceedings Of The 96th Annual Virginia Academy Of Science Meeting, 2018, Virginia Academy Of Science

Virginia Journal of Science

Proceedings of the 96th Annual Virginia Academy of Science Meeting, May 23-25, 2018, at Longwood University, Farmville, Virginia.

Biogeochemical Cycling Of Selenium In The Arctic Ocean, Kyle M. Mcquiggan

OES Theses and Dissertations

Changes in the global climate may have a pronounced effect on the biogeochemical cycling of trace elements like selenium (Se) in the Arctic Ocean. This study described the first quantitative examination of the biogeochemical cycle of selenium in the Amerasian Basin, providing the baseline from which future changes can be identified. Aerosol, dissolved and particulate water samples were collected for Se determinations during the U.S. GEOTRACES GN01 Arctic expedition that sampled the two parts of the Amerasian Basin in 2015: The Makarov Basin on the way to the North Pole and the Canada Basin on the return trip to Dutch …

Reproductive Correlates Of A Perineal Gland In The Hispid Cotton Rat, Robert K. Rose, Julie A. Winchell

Virginia Journal of Science

During studies of the annual cycle of reproduction in the hispid cotton rat (Sigmodon hispidus) in southeastern Virginia, we discovered an anal (more specifically, perineal) gland that is present only in males during the breeding season.  The perineal gland encircles the lower end of the rectum and has ductal connections to the urethra, through which its secretions probably are delivered.  This fatty gland is highly developed in breeding males but, like the testes and seminal vesicles, regresses during the winter non-breeding season. The prominence and cyclicity of the perineal gland suggest that it somehow facilitates normal reproduction.  The …

Assessing Trade-Offs In Large Marine Protected Areas, Tammy E. Davies, Graham Epstein, Stacy E. Aguilera, Cassandra M. Brooks, Michael Cox, Louisa S. Evans, Sara M. Maxwell, Mateja Nenadovic, Natalie C. Ban

Biological Sciences Faculty Publications

Large marine protected areas (LMPAs) are increasingly being established and have a high profile in marine conservation. LMPAs are expected to achieve multiple objectives, and because of their size are postulated to avoid trade-offs that are common in smaller MPAs. However, evaluations across multiple outcomes are lacking. We used a systematic approach to code several social and ecological outcomes of 12 LMPAs. We found evidence of three types of trade-offs: trade-offs between different ecological resources (supply trade-offs); trade-offs between ecological resource conditions and the well-being of resource users (supply-demand trade-offs); and trade-offs between the well-being outcomes of different resource users …

Global Conservation Status Of Marine Pufferfishes (Tetraodontiformes: Tetraodontidae), Emilie Stump, Gina M. Ralph, Mia T. Comeros-Raynal, Keiichi Matsuura, Kent E. Carpenter

Biological Sciences Faculty Publications

Puffers are biologically and ecologically fascinating fishes best known for their unique morphology and arsenal of defenses including inflation and bioaccumulation of deadly neurotoxins. These fishes are also commercially, culturally, and ecologically important in many regions. One-hundred-and-fifty-one species of marine puffers were assessed against the International Union for Conservation of Nature (IUCN) Red List Criteria at a 2011 workshop held in Xiamen, China. Here we present the first comprehensive review of puffer geographic and depth distribution, use and trade, and habitats and ecology and a summary of the global conservation status of marine puffers, determined by applying the International Union …

Compositional Changes In Two Small Mammal Communities During Succession In Southeastern Virginia, Robert K. Rose, Robyn M. Nadolny, Jay Kiser, Stephen E. Rice, Heather Green Salamone, Jana Eggleston, Holly D. Gaff

Virginia Journal of Science

Changes in the composition of two small mammal communities were studied during eight and nine years of ecological succession in southern Chesapeake, Virginia. Using monthly live-trapping on grids of similar size and history since their abandonment as agricultural fields, we learned that house mice were early colonists on one grid but not the other.  Two species of herbivorous rodent and the granivorous eastern harvest mouse were numerically dominant on both grids across the study.  Some species disappeared early on one grid but persisted to the end at the other.   The two arboreal small mammals, golden and white-footed mice, were most …

Contextual Framework Of Communications Functions Supporting Complex System Governance, Charles Wesley Chesterman Jr.

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop a systems theory-based contextual framework of communication functions supporting complex system governance using an inductive research design. Communication, as one aspect of Management Cybernetics (communication and control for effective system organization) constructed of channels of communication, provides for the movement of information internally and externally for a system. This flow reflecting new information, decisions, questions, and intelligence is critical for viability of a system. This research looked for communication mechanisms as developed in system theory, communication theory, management theory, and organizational theory. The literature indicates the importance of communications, but a systemic …

The Evaluation Of Enhancing Biological Phosphorus Removal And Improving Settleability Using Mainstream Hydrocyclones For External Selection, Amanda Carrie Ford

Civil & Environmental Engineering Theses & Dissertations

Hydrocyclones, which receive mixed liquor tangentially, separate lighter solids from more dense solids through their tapered shape. Increasing the velocity of liquid as it moves downward allows for the selection of a desired solids fraction. Limited research has been conducted utilizing 20 m³hr^-1 hydrocyclones, with the intent of improving settleability and biological phosphorus removal (Bio-P) for mainstream processes. Improved settleability would allow for increased capacity in the secondary clarifiers which prevents the loss of biomass and subsequent treatment disruption, especially during wet weather scenarios. In addition, treatment intensification can be accomplished by maintaining a higher mixed liquor …

Fishery Interaction Modeling Of Cetacean Bycatch In The California Drift Gillnet Fishery To Inform A Dynamic Ocean Management Tool, Nicholas B. Sisson

Biological Sciences Theses & Dissertations

Understanding the drivers that lead to interaction between target species in a fishery and marine mammals is a critical aspect in efforts to reduce bycatch. In the California drift gillnet fishery static management approaches and gear changes have reduced bycatch but neither measure ascertains the underlying dynamics causing bycatch events. To avoid further potentially drastic measures such as hard caps, dynamic management approaches that consider the scales relevant to physical dynamics, animal movement and human use could be implemented. A key component to this approach is determining the factors that lead to fisheries interactions. Using 25 years (1990-2014) of National …

Tracing Actin Filament Bundles In Three-Dimensional Electron Tomography Density Maps Of Hair Cell Stereocilia, Salim Sazzed, Junha Song, Julio Kovacs, Willi Wriggers, Manfred Auer, Jing He

Computer Science Faculty Publications

Cryo-electron tomography (cryo-ET) is a powerful method of visualizing the three-dimensional organization of supramolecular complexes, such as the cytoskeleton, in their native cell and tissue contexts. Due to its minimal electron dose and reconstruction artifacts arising from the missing wedge during data collection, cryo-ET typically results in noisy density maps that display anisotropic XY versus Z resolution. Molecular crowding further exacerbates the challenge of automatically detecting supramolecular complexes, such as the actin bundle in hair cell stereocilia. Stereocilia are pivotal to the mechanoelectrical transduction process in inner ear sensory epithelial hair cells. Given the complexity and dense arrangement of actin …

Prediction Of Lncrna-Disease Associations Based On Inductive Matrix Completion, Chengqian Lu, Mengyun Yang, Feng Luo, Fang-Xiang Wu, Min Li, Yi Pan, Yaohang Li, Jianxin Wang

Computer Science Faculty Publications

Motivation: Accumulating evidences indicate that long non-coding RNAs (lncRNAs) play pivotal roles in various biological processes. Mutations and dysregulations of lncRNAs are implicated in miscellaneous human diseases. Predicting lncRNA–disease associations is beneficial to disease diagnosis as well as treatment. Although many computational methods have been developed, precisely identifying lncRNA–disease associations, especially for novel lncRNAs, remains challenging.

Results: In this study, we propose a method (named SIMCLDA) for predicting potential lncRNA– disease associations based on inductive matrix completion. We compute Gaussian interaction profile kernel of lncRNAs from known lncRNA–disease interactions and functional similarity of diseases based on disease–gene and gene–gene onotology …

Anthropomorphically Inspired Design Of A Tendon-Driven Robotic Prosthesis For Hand Impairments, Manali Bapurao Bhadugale

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents the design of a robotic prosthesis, which mimics the morphology of a human hand. The primary goal of this work is to develop a systematic methodology that allows a custom-build of the prosthesis to match the specific requirements of a person with hand impairments. Two principal research questions are addressed toward this goal: 1) How do we cater to the large variation in the distribution of overall hand-sizes in the human population? 2) How closely do we mimic the complex morphological aspects of a biological hand in order to maximize the anthropomorphism (human-like appearance) of the robotic …

A Dual Resonant Transformer And A Dielectric Antenna For Picosecond Pulse Radiation, Khiem Huynh

Electrical & Computer Engineering Theses & Dissertations

This thesis discusses the development of a pulsed power system for high power picosecond pulse radiation. In the system, a charging transformer, which generates a high voltage pulse of ~100 kV, can be used for charging a transmission line in less than 100 ns. Such a short pulse could cause a peak gap switch to break down and generate a picosecond pulse transient for radiation. A dielectric antenna, if fed with the high voltage picosecond pulses, can radiate them to targets made of high dielectric materials. Biological tissues, for instance, can be targeted for electrostimulation.

The transformer was designed considering …

3d Bioprinting Systems For The Study Of Mammary Development And Tumorigenesis, John Reid

Electrical & Computer Engineering Theses & Dissertations

Understanding the microenvironmental factors that control cell function, differentiation, and stem cell renewal represent the forefront of developmental and cancer biology. To accurately recreate and model these dynamic interactions in vitro requires both precision-controlled deposition of multiple cell types and well-defined three-dimensional (3D) extracellular matrix (ECM). To achieve this goal, we hypothesized that accessible bioprinting technology would eliminate the experimental inconsistency and random cell-organoid formation associated with manual cell-matrix embedding techniques commonly used for 3D, in vitro cell cultures. The first objective of this study was to adapt a commercially-available, 3D printer into a 3D bioprinter. Goal-based computer simulations were …

Study Of Abc Membrane Transporters In Single Live Cells, Preeyaporn Songkiatisak

Chemistry & Biochemistry Theses & Dissertations

The multidrug ATP-binding cassette (ABC) membrane transporters (efflux pumps) are found in both prokaryotes and eukaryotes and they can extrude diverse structurally unrelated substrates, such as antibiotics and chemotherapeutic agents out of the cells. The efflux pumps are responsible for multidrug resistance (MDR) and the failure of numerous treatments in infections and cancers. All ABC membrane transporters share a common modular topology containing two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs). The underlying molecular mechanisms regarding how the similar structural ABC membrane transporters could selectively extrude a wide variety of substrates and cause MDR, are not yet fully …

Psychosocial Determinants Of Medication Adherence Among Hiv-Positive Individuals In Mexico City, Anthony Vajda

Counseling & Human Services Theses & Dissertations

This dissertation examined the relationships among disclosure, social support, exposure to violence, impulsivity, depression, stressors, and medication adherence, using a correlational design and a sequential logistic regression. The researcher used two samples of 146 from an archival data set of participants to create two subsets of the data (Data Set 1 & Data Set 2). These participants had been diagnosed with a mental illness and were prescribed a medication regimen for HIV treatment at the time of intake in a specialized clinic in Mexico City. Archival data was obtained through a demographic intake questionnaire and the use of valid and …

Policing The Drinking Community: An Assessment Of The Criminal Justice Response To Drunk Driving And Alcohol Related Crashes (1985 -2014), Richard James Stringer

Sociology & Criminal Justice Theses & Dissertations

The objective of this study was to analyze the relationships among arrests, informal alcohol related social norms, and alcohol related fatal crashes in the U.S. from 1985-2014. Despite inexorable efforts to eliminate drunk driving, approximately twenty percent of the population drives after drinking (Drew, 2010). Although law enforcement arrests play a key part in policies to deter drunk driving, enforcement of DUI laws varies widely across the country (Erickson et al., 2015). However, no project has explored the relationship between structural factors related to community norms, enforcement, and automobile crashes. Thus, this project adds to the literature and understanding of …

The Relationship Between Course Delivery Mode And Location With Course Success For Dual Enrolled Students, Dean Morris Roughton

Educational Leadership & Workforce Development Theses & Dissertations

High school dual enrollment has increased dramatically in recent years, growing 75% nationally between academic years 2002-03 and 2010-11 (Borden, Taylor, Park, & Seiler, 2013). Proponents of dual enrollment programs cite long-term, positive student outcomes for dual enrollment students: higher GPAs in college as adults (Allen & Dadgar, 2012; Jones, 2014; Karp, Calcagno, Hughes, Jeong, & Bailey, 2007), higher first year persistence rates in college (Jones, 2014; Karp et al., 2007), faster time to degree completion (Allen & Dadgar, 2012; Ganzert, 2014; Hughes, 2016), and higher college graduation rates (Ganzert, 2014; Hughes, 2016). However, very little research has focused on …

Non-Invasive Picosecond Pulse System For Electrostimulation, Ross Aaron Petrella

Electrical & Computer Engineering Theses & Dissertations

Picosecond pulsed electric fields have been shown to have stimulatory effects, such as calcium influx, activation of action potential, and membrane depolarization, on biological cells. Because the pulse duration is so short, it has been hypothesized that the pulses permeate a cell and can directly affect intracellular cell structures by bypassing the shielding of the membrane. This provides an opportunity for studying new biophysics. Furthermore, radiating picosecond pulses can be efficiently done by a compact antenna because the antenna size is comparable to the pulse width. However, all of the previous bioelectric studies regarding picosecond pulses have been conducted in …

Current Radiation Safety Practices Of United States Dental Hygienists, Kimberly Lintag

Dental Hygiene Theses & Dissertations

Problem: The purpose of this study was to determine licensed dental hygienists’ current radiation safety practices.

Methods: Data was collected with a 22 item, IRB exempt online survey administered to a sample of 1,500 U.S. dental hygienists who were subscribers of a professional journal. Questions focused on respondents’ use of ADA selection criteria guidelines, policies implemented by their dental practice, and hand-held portable x-ray device use and training. A response rate of 38% (N=566) was obtained. Cross tabulations were obtained using logistic regression and general linear models for significance at a 0.05 level.

Results: A majority of respondents had an …

Investigation Of Microfluidic Kelvin Water Dropper And Its Applications In Contact And Contactless Electrowetting, Elias Yazdanshenas

Mechanical & Aerospace Engineering Theses & Dissertations

A typical Kelvin water dropper is a device that can convert gravitational potential energy to a high voltage electrostatic. This device consists of two inductors, two collectors, tubes, and electrical connections. A Kelvin water dropper is able to generate extremely high voltage by separating ions using two positive feedback loops. A Kelvin water dropper provides a low cost solution for the applications in which high voltage is needed. In the present research, low cost Microfluidic Kelvin Water Droppers (MKWDs) were developed and built in house for electrowetting applications. Two MKWDs with different tube inner diameters (254 and 508 μm) were …

Instructional Designer Awareness And Application Of Strategies To Manage Cognitive Load, Justin A. Sentz

STEMPS Theses & Dissertations

This study examined how practicing instructional designers manage cognitive load in a standardized scenario as they select and implement instructional strategies, message design, content sequencing, and delivery media within various domains with learners at different levels of expertise. The study employed a quasi-experimental, mixed methods design to gain insight into how practicing instructional designers perceive their awareness of strategies to manage cognitive load and implement those strategies within a standardized design scenario. The research design involved the collection of quantitative data from the participants during an initial web-based questionnaire and a second collection of both quantitative and qualitative data as …

Understanding The Mechanical Behavior Of Costal Cartilage At Their Curved Exterior Surface Via A Tactile Sensor With A Built-In Probe For Distributed-Deflection Detection, Jiayue Shen

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation is aimed to determine the mechanical properties at the exterior surface of costal cartilages (CC) and examine how they vary with the cartilage length and the anatomical sites of CC in the ribcage via conformal indentation testing which is built upon a tactile sensor for distributed-deflection detection. The sensor entails a rectangular Polydimethylsiloxane (PDMS) microstructure sensing-plate integrated with a 5 ×1 transducer array with 0.75mm spatial resolution underneath and a built-in probe of 0.5mm×5mm×3mm above. By pressing the sensor against the exterior surface of a CC tissue with a pre-defined indentation pattern, the sensor conforms to the curved …

The Effect Of The Behavioral Analysis Feedback Model On Improving Performance Of Nursing Students During Clinical Rotations, Melanie Elizabeth Ross

STEMPS Theses & Dissertations

This study explored the effects the Behavioral Analysis Feedback (BAF) Model had on improving nursing student’s performance. Research studies surrounding feedback primarily centered on frameworks designed as models for delivering feedback as well as the timing for delivering feedback. In addition, past research has also focused on individual elements that affect performance with little regard to environmental elements. The BAF Model was conceptualized based on the importance of providing feedback to nursing students while emphasizing three individual and three environmental elements that have the potential to influence behavior.

This multiple measure, single-case study utilized a quasi-experimental pre-post intervention study design. …

Modeling Effects Of Rainwater Harvesting Systems On Water Yield Increase And Non-Beneficial Evaporation Reduction To Sustain Agriculture In A Water-Scarce Region Of China, Tennille Wade

Civil & Environmental Engineering Theses & Dissertations

The northwestern region of China, which has an arid/semiarid climate, relies heavily on agriculture to provide food for the growing population. Climate change is affecting water availability in the region, causing long periods of drought and water scarcity followed by shorter periods of heavy rainfall and excess water availability. The ridge and furrow rainwater harvesting systems (RFRWHS) are a means of solving the problem of water scarcity; the systems can replenish soil moisture, reduce non-beneficial evaporation from bare soils, and increase surface water yield. In such a region, the hydrologic cycle is dominated by soil evaporation, leading to minimal surface …

Reimagining The Chalk Talk: Animated Handwriting As A Social Cue To Improve Motivation In Multimedia Video Lessons, Hillary C. Kaplowitz

STEMPS Theses & Dissertations

Animated handwriting in multimedia video lessons, such as those popularized by the Khan Academy, has reimagined the classic teaching technique of writing on a chalkboard while lecturing for online delivery. This digital chalk talk effect mimics classroom lectures where words are written letter by letter on a chalkboard as they are spoken. Low-cost applications, tablets, and document cameras allow instructors at all levels to easily create their own animated handwritten videos. As adoption increases, it is important to understand the effects of this strategy.

This study employed a true experimental, between-subjects, posttest design that compared multimedia lessons with different text …