4,972 Works

Classical and quantum dynamics of Bose-Einstein condensates

Ranchu Mathew
After the first experimental realization of a Bose-Einstein condensate (BEC) in 1995, BECs have become a subject of intense experimental and theoretical study. In this dissertation, I present our results on the classical and quantum dynamics of BECs at zero temperature under different scenarios. First, I consider the analog of slow light in the collision of two BECs near a Feshbach resonance. The scattering length then becomes a function of the collision energy. I derive...

SUGARCANE AGRICULTURE AS AN AGENT OF GEOMORPHIC CHANGE AND STREAM DEGRADATION IN BRAZIL

Maira Ometto Bezerra
Intensive agriculture profoundly alters the geomorphology, hydrology and nutrient balances of catchments. The result is the degradation of headwater stream ecosystems via inputs of excess sediments, surface runoff, and nutrients. To mitigate the negative effects on streams, watershed managers can implement riparian buffers, which are designed to intercept, process, store, and remove excess material from upslope agricultural source areas. While extensive research on those topics exists for temperate regions of developed countries, little is known...

WATER IN THE EARLY SOLAR SYSTEM: INFRARED STUDIES OF AQUEOUSLY ALTERED AND MINIMALLY PROCESSED ASTEROIDS

Margaret McAdam
This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their...

REMOTE ESTIMATION OVER USE-DEPENDENT CHANNELS

David Pratt Ward
This dissertation investigates communication and estimation over channels whose transmission characteristics change with previous channel utilization and transmissions. We define three classes of channels: 1) Use-dependent discrete switching channels, 2) Use-dependent packet-drop channels, and 3) Shared-resource multiple packet-drop channels. In each of these classes of channels, there is a channel state that determines the channel's transmission characteristics. For use-dependent discrete switching and packet-drop channels, there is a channel transmission policy that calculates the input to...

Absorption and metabolism of 3-MCPD 1-monopalmitate in rats

Boyan Gao
Fatty acid esters of 3-monochloropropane 1,2-diol (3-MCPD esters) are a group of potential chemical toxicants. Their toxic effects primarily include nephrotoxicity and hepatotoxicity. To understand the toxic mechanisms of 3-MCPD esters, one of the key points is to advance the understanding of their metabolic mechanisms in vivo. This dissertation investigated 1) the absorption and kinetics of 3-MCPD 1-monopalmitate in rats, 2) the possible metabolites of 3- MCPD 1-monopalmitate after oral administration to rats, and 3)...

Benchmarking Charge Exchange Theory in the Dawning Era of Space-Borne High-Resolution X-ray Spectrometers

Gabriele Betancourt-Martinez
Charge Exchange (CX) is a process in which a highly charged ion captures one or more electrons from a neutral atom or molecule into an excited state during a close interaction. The electron's subsequent radiative cascade to the ground state produces diagnostic line emission in the X-ray band. CX with solar wind ions occurs frequently in the solar system, and CX may also occur astrophysically. In order to properly identify CX in astrophysical spectra and...

HYDROLOGY, SOIL REDOX, AND PORE-WATER IRON REGULATE CARBON CYCLING IN NATURAL AND RESTORED TIDAL FRESHWATER WETLANDS IN THE CHESAPEAKE BAY, MARYLAND, USA

Amr El Shahat Sedik Keshta
Tidal freshwater wetlands are key sites for carbon (C) sequestration and main component in the global C budget. The overall research objective of my dissertation was to examine the physical and biogeochemical processes that impact C cycling in tidal freshwater wetlands. One natural and one restored tidal freshwater wetland (salinity < 0.3 ppt) were selected in Maryland, USA along the Patuxent River. Data logging water recorders were installed in wells at each habitat in February...

NARRATIVES OF FIT: UNDERSTANDING WOMEN FACULTY STORIES OF MAKING SENSE AND FINDING PLACE IN GENDERED ORGANIZATIONS

Jessica Bennett
“Fit” is used widely in academia to indicate whether someone is admittable, hirable, or tenurable, despite concerns that fit is poorly defined and could serve as a covering term for bias. The small body of literature on faculty fit focuses primarily on the complementary attributes that exist between research institutions and their academic staff, and the role of fit as a predictor of outcomes such as intention to leave, productivity, stress, vitality, and satisfaction. Little...

COLD WAR II: UKRAINIAN SOVEREIGNTY AND IDENTITY

Thomas Laurence McCloskey
Ukraine’s 2014 Revolution of Dignity showcases tensions between nationalism and internationalism in a post-Cold War era. Ukraine’s political leaders and ordinary citizens express opposing views about the identity and sovereignty of their nation, as some want closer ties with the European Union, while others seek closer relations with the Russian Federation. The myths and memories of Ukraine’s Cossack past, as well as its time in the former Soviet Union, animate discourses throughout the conflict. These...

Not your terrorist: Case studies examining the intersectional identities and aspirations of Arab American Muslim middle school boys

Dina Shafey
Arab Muslim boys living in the United States have experienced varying levels of public scrutiny since 9/11 and prior to. Public perceptions of these experiences are centered on media-driven representations; often inaccurate depictions of the nuanced lives of these boys. While Arab Muslims have lived in the United States more than a century, their lived experiences, particularly experiences while in school are missing. This research study examined how Arab American Muslim Middle School boys perceived...

A Proposed Index to Detect Relative Item Performance when the Focal Group Sample Size is Small

Kari Hansen
When developing educational assessments, ensuring that the test is fair to all groups of examinees is an essential part of the process. The primary statistical method for identifying potential bias in assessments is known as differential item functioning (DIF) analysis, where DIF refers to differences in performance on a specific test item between two groups assuming that the two groups have an overlap in their ability distribution. However, this requirement may be less likely to...

TEACHERS’ PERCEPTIONS OF THE IMPACT OF iPAD© USE IN THE CLASSROOM ON THEIR INSTRUCTIONAL PRACTICE

As technology devices, access, and availability continue to grow exponentially in our society, school systems need to align their educational resources, tools and professional growth programs to have a positive effect on teaching and learning in today’s 21st century classroom. Studies have shown the integration of technology in the classroom can have a positive influence on teaching and learning. The purpose of this study was to investigate teachers’ perceptions of the impact that one device,...

LONGITUDINAL DYE DISPERSION AND SALT FLUX IN ESTUARIES

Wei Liu
Estuarine dispersion plays an important role in determining the fate of waterborne materials. It is a long-standing question in estuarine dynamics that is still not well understood. This dissertation revisits this problem by utilizing two tracers: dye and salt. Dye-release experiments and numerical modeling are conducted to investigate horizontal dispersion in a partially mixed estuary. Longitudinal dispersion of a dye patch shows strong flood-ebb asymmetry at early times after a dye release, with most of...

Electrically Induced Gelation, Rupture, and Adhesion of Polymeric Materials

Ankit Gargava
There has been considerable interest in developing stimuli-responsive soft materials for applications in drug delivery, biosensing, and tissue engineering. A variety of stimuli have been studied so far, including temperature, pH, light, and magnetic fields. In this dissertation, we explore the use of electric fields as a stimulus for either creating new soft materials or for rupturing existing ones. Our materials are based typically on biocompatible polymers such as the polysaccharides alginate, chitosan, and agarose....

Electroosmotic Soft Actuators

Deepa Sritharan
This dissertation details the research involved in creating the first paper-based soft actuator driven by electroosmosis. To accomplish this, research breakthroughs were made in the fields of electrokinetic pumping and device manufacturing using soft materials. Electroosmosis is an electrically induced microfluidic flow phenomenon. When an electric field is applied to the fluid, across the microchannels, electroosmotic flow occurs in the direction of the applied electric field. In this work, liquid was electroosmotically displaced within a...

Phantom Futures: The Cultural Politics of Education-Related Debt

Jaime Madden
My dissertation examines the cultural politics of education-related debt. In a time of spiraling higher education costs, I focus on students who face challenges repaying debts and participating productively in the market economy. Taking on debt in college orients students towards a supposedly “better future.” But what happens to those who are unable or unwilling to realize these better futures? This is the broad question that motivated my dissertation. The students I interviewed often complicated...

DEMONSTRATION OF A QUANTUM GATE WITH ULTRAFAST LASER PULSES

Jaime David Wong Campos
One of the major problems in building a quantum computer is the development of scalable and robust methods to entangle many qubits. Quantum computers based on trapped atomic ions are one of the most mature and promising platforms for quantum information processing, exhibiting excellent coherence properties, near-perfect qubit detection efficiency, and high-fidelity entangling gates. Entangling operations between multiple ions in a chain typically rely on qubit state-dependent forces that modulate their Coulomb-coupled normal modes of...

An Evaluation of Clustering Algorithms for Modeling Game-Based Assessment Work Processes

William Austin Fossey
Game-based assessments (GBAs) use game design elements to make assessments more engaging for students and capture response data about work processes. GBA response data are often too complex to plan for every potential response pattern, so some researchers have turned to exploratory cluster analysis to classify students’ work processes. This paper identifies the design elements specific to GBAs and investigates how well k-means, self-organizing maps (SOM), and robust clustering using links (ROCK) clustering algorithms group...

TEMPORAL DISTRIBUTION OF PRACTICE AND INDIVIDUAL DIFFERENCES IN THE ACQUISITION AND RETENTION OF L2 MANDARIN TONAL WORD PRODUCTION

Man Li
This dissertation investigated the effects of temporal distribution of practice (relatively massed vs. distributed) on the learning and retention of oral Mandarin tonal word production by native English-speaking adults within the theoretical framework of skill acquisition and retention theories. The present study focused on oral production of Mandarin two-syllable words as a function of temporal distribution of practice. It also explored whether the effects of this distribution differ depending on the type of knowledge to...

Asian Studies Scholars and Their Research at the University of Maryland

Cynthia Sorrell & Yukako Tatsumi
Report documenting research practices and needs of Asian Studies faculty at a public university.

Development of Management Thought: Volume 1 (1978, 2017)

Richard Hoffman
This collection of articles and summaries of the work of early management thinkers and practitioners was completed as part of a doctoral seminar on Management Thought History & Development (W605) I took in the Spring, 1978 at the Graduate School of Business at Indiana University-Bloomington with Dr. John F. Mee (PhD Ohio State). At that time Dr. Mee was the Mead Johnson Professor of Management at Indiana and former president of the Academy of Management....

The Relationships Between Racial Discrimination, Gender Discrimination, Childhood Socialization Messages, and the Self-Esteems of Professional Black Women

Jacqueline Finney Brown
This study investigated the relationships between perceived racial discrimination, perceived gender discrimination, childhood socialization messages and the global and situational self-esteems of Professional Black women. The sample population was 119 Professional Black women. The Tennessee Self-Concept Scale Form C was used to measure global self-esteem. The Survey of Black Women's Perceptions was used to measure degree of self-esteem enhancement of childhood socialization messages, levels of success related to the Life Tasks of Work, Love, Friendship,...

The Relationship of Self-Esteem, Racial Identity, and Membership in an Africentric Organization to Academic Achievement Among African-Americans

Shirley Y. Jennings
Non-cognitive variables have been found to be better predictors of academic achievement than traditional cognitive-based test scores or high school graduation rank for African-American students. Studies by Tracey and Sedlacek (1984 and 1985) have indicated that non-cognitive variables such as self-esteem, understanding racism, having a supportive network, and possessing other social skills can predict persistence and achievement of African-American university students. This study has examined the relationship among non-cognitive variables of self-esteem, racial identity, and...

The intersection of urban-rural divisions and the enumerator effect on Malian opinions of Western military presence

J.T. Stanley
Hello I had reached out to Patti Cossard about my delayed letter of support and she said to submit my project even though my Letter of Support will come next week.

The Effects of Listening to Certain Kinds of Music On Test Performance and Test Anxiety on a Special Education Student

Elena Storey
This paper focuses on the effects of listening to certain kinds of music on test anxiety and test performance for a Special Education student. The researcher explored classical music as the focus.

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