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Instrumentation Of The Universal Clamp And Modeling In Biochemistry, Jiang Wu

Open Access Dissertations

Instrumentation of the universal clamp. Voltage clamp has been an important method for studying current-voltage relationships across membranes of excitable cells such as neurons and muscles. The conventional voltage clamp amplifiers have been based on analog feedback controls. In this study a prototype digital voltage clamp system has been developed, which uses a digital signal processor (DSP) to implement feedback controls. The development was guided by computer simulation of both analog and digital voltage clamps that interact with a neuron model. Feasibility of the digital voltage clamp was demonstrated by its performance in an experiment comparable to that of an …

Examining The Processes Controlling Water Column Variability In Narragansett Bay: Time Series Data And Numerical Modeling, Deanna L. Bergondo

Open Access Dissertations

Narragansett Bay is an important resource to the state of Rhode Island for recreational and commercial use. Eutrophication of coastal waters and its associated oxygen demand are of increasing concern for Narragansett Bay. This project focused on continuous in situ measurements and three-dimensional model simulations to better understand the physical, biological and chemical processes which occur in the Bay. Measurements of temperature, salinity, dissolved oxygen, pH, chlorophyll and depth were obtained to gain insight into the process that contribute to phytoplankton production and hypoxia in the Bay. Six major hypoxic events were captured during the summers of 2001 and 2002. …

Ecomorphology Of The Temperate Scleractinian Astrangia Poculata: Coral-Macroalgal Interactions In Narragansett Bay, Sean Patrick Grace

Open Access Dissertations

Corals and macroalgae often co-occur on temperate reefs, where macroalgae provide a majority of the bio-complexity and small scleractinian corals occur in low abundance. Macroalgae typically outcompete adjacent organisms for resources such as space, light, and nutrients, and one mechanism for this competitive success is abrasion. This study explores factors that may influence the interactions between corals and macroalgae, in particular macroalgal abrasion, on a temperate reef in Narragansett Bay, Rhode Island. Chapter One examines how exposure, depth and orientation influence the abundance and morphology of the coral Astrangia poculata, as well as the percent cover of macroalgae and other …

Culture Of Summer Flounder Paralichthys Dentatus: Environmental And Endocrine Synchronization Of Growth And Settlement In Larvae And Identification Of Stressors In Juveniles, Steven Gavlik

Open Access Dissertations

This dissertation addresses the variability in settlement behavior, growth and development during metamorphosis of summer flounder. There were three objectives: (1) Expand basic knowledge of hormonal and environmental factors that regulate timing of metamorphosis, (2) develop hormonal and environmental techniques that promote synchronization of metamorphic growth and settling behavior in order to eventually reduce cannibalism in juveniles, and (3) identify stressful culture practices and evaluate their long-term effects on growth in juvenile flounder. The first and second objectives were accomplished through manipulations of cortisol and thyroxine and of rearing salinity. Endogenous whole-body cortisol concentrations increased through the late larval stages, …

Essays On Fisheries Management, Ramesh Baskaran

Open Access Dissertations

This dissertation consists of three manuscripts that explore the present issues on both commercial and recreational fishery management in the United States of America. It reviews recent development and different management strategies in fisheries, which shows the need to expand and improve the present fishery management in order to entail sustainability of resources as well as the economic well-being of the fishery participants. The first manuscript is policy oriented and suggests a rights-based cooperative approach may provide an incentive for the rational management of Atlantic sea scallop fishery. Due to excessive harvest capability and regulatory inefficiencies, the sea scallop industry …

Predicting Condition Of Small Estuarine Systems Along The United States' Atlantic Coast, Jeffrey W. Hollister

Open Access Dissertations

Anthropogenic activities are known to degrade the ecological condition of estuaries. Also, numerous studies find links between landscape structure and estuarine condition. From these relationships, it is possible to build predictive models of estuarine condition. In this study, I examined issues of data quality, scale, and statistical approach to developing predictive models of estuarine sediment metal concentrations in the Mid-Atlantic region of the United States. I assessed the accuracy of the National Land Cover Dataset (NLCD) at multiple scales by comparing it with reference data from Rhode Island and Massachusetts. Area of developed lands, agriculture, forest and water had acceptable …

Resilience In Ex-Refugees From Cambodia And Vietnam, Lynne Ee Lin Yong

Open Access Dissertations

The negative impacts of various forms of trauma on the physical and mental health of victims are well documented, including the experiences of the French Indo-Chinese, who suffered a range of traumatic experiences ranging from displacement to torture. However, a sizable percentage of French Indo-Chinese refugees living in the U.S. do not exhibit psychopathology. Very little is known about the Indo-Chinese refugees who are not seeking services and are doing well in their host country. This study focused on resilient Cambodian and Vietnamese ex-refugees, with the goal of identifying resiliency factors and their underlying processes, in order to inform the …

Suicide Assessment By Psychiatric Mental Health Nurses: A Phenomenographic Study, John M. Aflague

Open Access Dissertations

Suicide is the eleventh leading cause of mortality in the United States. This study explored suicide assessment by psychiatric nurses. The primary aims of this study were to gain an understanding of nurses' conceptions regarding suicide and suicide assessment, describe the strategies of suicide assessment adopted by psychiatric nurses, and contrast these to contemporary standards and practice guidelines of suicide assessment.

The research design was an inductive descriptive phenomenographic study. The nurse participants consisted of a snowball sample of six psychiatric nurses practicing in two psychiatric settings. The data were collected through participant observations of nurses' assessing patients and semi-structured …

Forensic And Biological Applications Of Vibrational Spectroscopy, Edita Botonjic

Open Access Dissertations

Determination of the age of a bloodstain can be used to establish the time when a crime was committed. As blood ages, deoxyhemoglobin (HbO 2) is converted into methemoglobin (MetHb), which is evident by the color change from red to brown. Fluctuations in temperature will cause blood to age at a non-constant rate. It has been shown that higher temperatures cause deoxyhemoglobin to oxidize more rapidly to methemoglobin. Human blood from vein and capillary vessels was used in this investigation. The samples were prepared by placing blood on various substrates such as gauze and watch glasses. Mid-IR and near-IR spectra …

Survivorship Of A Low-Grade Glioma Brain Tumor, Cynthia A. Bautista

Open Access Dissertations

Due to dramatic improvements in diagnosis, treatment options, and improved survival rates, the experience of cancer is changing. Little is known, however, about which factors facilitate positive adaptation for individuals who survive cancer. Research in the area of brain tumor survivorship is limited and provides minimal understanding of the survivor's experience. The purpose of this study was to describe the survivorship experience of adults who were one to four years posttreatment for a low-grade glioma brain tumor and to explore how family, friends, employers, and health care providers had been helpful in the transition back to life after treatment. Eight …

Potential Use Of Nitrogen-15 To Assess Nitrogen Sources And Fate In Narragansett Bay, Joaquin E. Chaves

Open Access Dissertations

Anthropogenic N inputs have been identified as the main source of N to Narragansett Bay, a relatively well-mixed estuary in the northeast coast of the United States. Despite a well constrained N budget high levels of primary production during the summer months, mostly in the form of sporadic "blooms", cannot be explained in terms of current budget estimates. Inputs from the adjacent Rhode Island Sound have been invoked as a potential source of N to account for the Bay's summer production. The dissolved inorganic nitrogen (DIN) from the Rhode Island Sound and the anthropogenic N entering the estuary through the …

Individual, Organizational, And Contextual Determinants Of Realized Strategy In Not-For-Profit Organizations, Henry T. Ulrich

Open Access Dissertations

This study addresses organizational direction form the perspective of organizational strategy. It explores the factors that influence realized strategy and especially the degree to which realized strategy is deliberate or emergent. A model is offered that proposes both direct and indirect factors as determinants of realized strategy. Specific direct and indirect factors are hypothesized and the relationships are statistically examined. The sample is composed of twenty nonprofit organizations with a primary base of operations in southern New England. Data was collected for multiple respondents within each organization representing the various levels of management. Most participating organizations were mid-sized, social service …

Sociocultural Contexts Of Asian American/Pacific Islander Women's Hiv Risk Enhancing/Reducing Responses, Jennifer C. Huang

Open Access Dissertations

HIV prevention issues for Asian American and Pacific Islander (API) women are complex and multifaceted. Comprehending the risk enhancing/reducing responses of API women in heterosexual relationships requires an examination of various sociocultural influences, such as gender roles, cultural expectations, community, economic conditions, acculturation and public policies that shape API women's decision-making and HIV risk enhancing/reducing responses. In order to address these issues, a mixed method study (i.e., qualitative and quantitative) was conducted to elucidate these sociocultural factors. Additionally, this study sought to investigate the various ecological levels that are associated with API women's sexual risk enhancing and reducing behaviors. Participants …

Determination Of Chlorophyll A Concentrations And Phytoplankton Primary Production In New England Estuarine Waters Using Ocean Color Remote Sensing From Low-Flying Aircraft, Darryl Joel Keith

Open Access Dissertations

The response of coastal systems to the addition of nutrients (especially nitrogen) is generally to stimulate phytoplankton biomass, measured using the concentration of chlorophyll a as a surrogate. However, the concentration and distribution of chlorophyll in the aquatic environment is variable in space and time. Historically, random to systematic design strategies have collected samples from specific locations in space (i.e. a point measurement). These strategies also are limited in sampling intra-annual, seasonal, and episodic events. Therefore, in order to sample on all time scales of interest over large geographic areas, a large number of point measurements and resources are required. …

Preparation Of Optically Pure Anti-Diolepoxides Of 2-Fluorobenzo[A]-Pyrene And Their Dna Adducts, Tianle Yang

Open Access Dissertations

Benzo[a]pyrene (BP) is a prototypical PAH and undergoes metabolic activation in vivo to highly mutagenic/carcinogenic diol epoxide derivatives (BPDE) that bind to DNA, ultimately initiating sequence-specific mutations. Structural studies indicate that BPDE-modified DNA exist in three major conformations: base-displacement, minor-groove, and classical intercalation. The relative conformeric ratios of these structures are known to vary depending on the modified base and the base sequences surrounding the lesion site. Our long-term research goal is to investigate the sequence dependent conformational heterogeneity of BP-DNA adducts with 19F NMR technique, which then requires preparation of (+)-and (−)-anti-2-fluorobenzo[a]pyrene diol epoxides (2-FBPDE) as 19F NMR probes. …

The Economic Consequences Of Fish Habitat Conservation And Management, Harold Frank Upton

Open Access Dissertations

Economic considerations can play a critical role in decisions regarding habitat alteration and protection. Yet the Essential Fish Habitat provisions of the Magnuson-Stevens Act are silent on the role of economic analysis in efforts to identify and protect marine fish habitat. On the federal level, actions taken to amend Fishery Management Plans (FMPs) or implement other regulations governing these fisheries must meet the requirements of Federal Laws and regulations, many of which address economic concerns. Perhaps of greater importance is the consideration of changes in social welfare associated with habitat management alternatives. Economic analysis can provide decision makers with information …

Transboundary Impacts Of Fishing Activities Along The Northeast Continental Shelf, Mark Lucas Soboil

Open Access Dissertations

In Manuscript I, I construct a stylized conceptual model to evaluate the international trade of the Atlantic groundfish fishery between the US and Canada. The model incorporates both the biological and economic components of the fishery, and explores the environmental, economic and some welfare implications through trade. First I explore the consequence of each country imposing a different fishery management regime. Second, I incorporate the spatial dynamics of the stock into this framework. Third, I use the conceptual model to discover the effects this may have on international trade. And finally I include the spatial dynamics of the stock into …

Regulation Of Cra, A Regulatory Gene Of Glycolytic And Gluconeogenic Pathways In Salmonella Enterica Serovar Typhimurium, James H. Allen

Open Access Dissertations

The Cra protein is a global regulator of carbon and energy metabolism for glycolysis and gluconeogenesis. The live oral vaccine candidate, Salmonella typhimurium SR-11 Fad, is unable to utilize gluconeogenic substrates as sole carbon sources and is avirulent and protective in BALB/c mice. Furthemore, the era gene is interrupted in this strain of Salmonella. The cra gene was suspected to be regulated by another global regulator, acetyl phosphate. To further investigate the regulation of the cra gene and to determine if gluconeogenesis is linked to virulence, mutations in the gluconeogenic genes fbp (fructose-1,6-bisphosphatase), maeB (NADP-dependent malic enzyme), and sfcA …

Organizational Climate For Diversity, Cultural Comfort, And Professional Relationships: Predicting Perceptions Of The Workplace Among Employees Of Color, Ivory Roberts-Clarke

Open Access Dissertations

Very little empirical research has been conducted to understand the unique experiences of employees of color. This study analyzed the perceptions that employees of color have about their places of employment. The total sample included 204 participants, 83 African Americans, 51 Caribbean/West Indians, 32 Latinos/Latinas, 15 Asians, 12 Africans, 8 Multi-ethnic individuals, 1 Native/Indigenous Subgroup, and 1 Middle Eastern. There were 133 women, 70 men, and 1 participant who did not identify his or her gender. Participants were recruited at professional conferences and via the internet where they anonymously completed a questionnaire at a website that was created for this …

The Birth Of Bizdames: A Rupture In The Conversation, Engaging The Body In Decision-Making, Kathleen Mallon

Open Access Dissertations

Organizational studies consistently find that managers spend more time talking than any other activity (Mintzberg, 1973; Simon, 1945), that strategic decisions are developed and enacted through interactive talk (Perlow, 2003; Shaw, 2002), and that a diversity of perspectives has a positive effect on decision-making and organizational performance (Agyris, 1977). Conversely, the evidence suggests that cultures that perpetuate silence are less effective (Bourgeois, 1985; Enz & Schwenk, 1991; Morrison & Milliken, 2000; Ryan & Oestreich, 1991). Thus, knowledge about the inter-relationship of the micro-mechanisms of silence and talk and their effect on organizational performance is critical to management theory and practice …

Revaluing The Literary Naturalist: John Burroughs's Emotive Environmental Aesthetics, Stephen Mark Mercier

Open Access Dissertations

This dissertation widens the circle of environmental aesthetics and ecocriticism by considering the role of the emotive in "appreciation." I demonstrate that emotion is a central feature in the literary naturalism of John Burroughs (1837-1921). Burroughs's model for environmental aesthetics combines narrative knowledge, sensory immersion, and emotional responses. Furthermore, I argue that Burroughs's "sentimental" emotions perform crucial roles in politics and therefore have serious implications for environmental consciousness. The rhetorical strategies inherent in Burroughs's paradigm for environmental aesthetics is essential to contemporary efficacious environmental discourse. This dissertation reclaims the importance of emotional affiliation with creatures, particularly birds, and their habitats. …

Macrozooplankton And Micronekton In The Arabian Sea Oxygen Minimum Zone, Mary Rapien

Open Access Dissertations

As part of the U.S. Joint Global Ocean Flux Study, zooplankton were collected day and night in vertically stratified MOCNESS net tows at six stations, during four seasonal cruises in the Arabian Sea. Organisms comprising the large size fraction, primarily fish, shrimp, amphipods, and euphausiids (macrozooplankton and micronekton), were identified and enumerated, and their abundance and distributions from 300-1000 m were examined in relation to environmental factors including the OMZ and the monsoon cycle. Contributions to carbon cycling were also estimated for several taxa. Few animals showed significant seasonal differences in abundance. Abundances and distributions of many taxa varied geographically, …

Queer Times: Christopher Isherwood's Modernity, Jamie M. Carr

Open Access Dissertations

This dissertation maps Christopher Isherwood's intellectual and aesthetic reflections from the late 1930s through the late 1970s. Drawing on the queer theory of Eve Sedgwick and the ethical theory of Michel Foucault, I illuminate Isherwood's post-war development of a queer ethos through his focus on the aesthetic, social, and historical politics of the 1930s in his novels Prater Violet (1945), The World in the Evening (1954), and Down There on a Visit (1962), and in his memoir, Christopher and His Kind: 1929-1939 (1976). Though he was a leftist writer in the 1930s, after this decade Isherwood comes to reflect on …

Older Lesbian Perspectives On Advance Care Planning For The End Of Life, Jean W. Powell

Open Access Dissertations

This study used grounded theory methodology and in-depth interviews with 12 older lesbians to investigate three research questions: (1) How do participants define and engage in the process of end-of-life planning? (2) Are there special issues associated with end-of-life planning that participants believe are different from those faced by heterosexual women? and (3) How do participants describe a good death and what steps might make a good death more likely? The participants consisted of an ethnically diverse sample of 12 self-identified lesbian women between 60 and 80 years of age. Each participant responded to semi-structured interview questions. Each interview was …

The Pros And Cons Of The Learned Helplessness Construct And The Battered Woman Syndrome: A Critical Analysis And Possible Reformulation, Lucille Andreozzi Stern

Open Access Dissertations

Two prevailing, contrasting theories, learned helplessness and health psychogenesis, have been proposed to describe and explain the battered woman's experience and response to domestic violence. This research examined the status (scientific adequacy) of each theory's database to determine where the preponderance of evidence lies.

The investigator articulated nine factors that differentiate the two theories. Trained independent raters then rated study outcomes as falling into one of three categories: pro-learned helplessness, pro-health psychogenesis, or supportive of both theories. Studies of two research samples (shelter and community) were identified and assessed (rated) along four methodological dimensions (sample, instrumentation, statistical analysis, and hypothesis …

Spatial Diffusion Model For Simulation Of Urban Land Cover Change, Yuming Wen

Open Access Dissertations

Spatial diffusion is a stochastic spatio-temporal process. Spatial diffusion phenomena occur because of the existence of a concentration gradient of information or material flow. At a regional level, most human-induced land-use and land-cover change, including urban land-cover change, can be considered as a spatial diffusion process. In this research, a spatial diffusion (SDIF) model has been developed to simulate urban land cover change at a regional level. This research aims to establish a theoretical framework for spatial diffusion modeling and build a spatial diffusion modeling system for simulation of urban land-cover change. The Chicago metropolitan region was selected as the …

Ecological Determinants Of Lyme Disease In An Endemic Community, Neeta N. Pardanani

Open Access Dissertations

We investigated potential risk factors for Lyme disease at the level of a southern Rhode Island community where vector ticks ( Ixodes scapularis Say) and human Lyme disease are endemic. We recruited homeowners with and without household histories of Lyme disease that would permit sampling of ticks and small mammals around the wooded edge of their properties. Entomologic factors including nymphal tick abundance, rates of tick infection with Lyme disease-causing bacteria (Borrelia burgdorferi ), and the density of infected nymphs were measured. We evaluated the relationship between these variables and the history of Lyme disease cases within households. The relationship …

Microstructure Studies In Surfacant Systems, Vivek Agarwal

Open Access Dissertations

Microstructures in two mixed surfactants systems that show novel transformations as a function of composition and temperature have been explored. Indirect imaging methods like Small Angle Neutron Scattering (SANS) along with direct imaging methods like Cryogenic Transmission Electron Microscopy (Cryo-TEM) and recently developed Freeze Fracture Direct Imaging (FFDD have been used extensively to characterize and identify the changes in the microstructures in the mixed surfactant systems as a function of composition, temperature and external force fields.

As water is added to a solution of an anionic surfactant, AOT (2 ethylhexyl sodium sulfosuccinate) and a zwitterionic surfactant, lecithin (phosphatidylcholine) in isooctane, …

Isolation Of Marine Metabolites From Symbiodinium Species Of Dinoflagellates, Katherine Evelyn Drainville-Higgins

Open Access Dissertations

The initial scope of this project was to determine if the symbiotic dinoflagellate, Symbiodinium sp., produces palytoxin, the highly lethal and complex compound originally found in the zoanthid, Palythoa spp. Through the examination of cell extracts made, this compound was not found. Instead, other secondary metabolites were isolated and their structures elucidated. The following is a summary of accomplishments. (1) The conditions to grow several strains of Symbiodinium organisms were investigated for the necessary extensive culturing required for cellular extraction. As a result, an isolate from Palythoa sp. obtained in Puerto Rico was successfully cultured. Previously, sustaining cultures of Palythoa …

Intracellular Dynamics Of Lead And Calcium In Lead-Exposed Cultured Neurons Of Aplysia Californica (Mollusca: Opisthobranchia), Catherine T. Tamse

Open Access Dissertations

The neurotoxin lead (Pb2+) is a continuing health and environmental problem. However, its neurotoxic mechanism remains unclear. Since calcium (Ca2+) is vital in cellular processes and with Pb2+ reported to interfere with Ca2+-mediated processes, the hypothesis that Pb2+ subverts Ca2+ homeostasis by entering cells through Ca2+ transport pathways and displacing intracellular Ca2+ ([Ca2+] i) was investigated. A multi-technique approach tested this hypothesis. Using cultured Aplysia bag cell neurons, changes in transmembrane Ca2+ flux after Pb2+ exposure were directly measured with the Ca2+-selective self-referencing electrode. Cumulative concentrations of extracellular Pb2+ produced a corresponding and significant (P < 0.05) increase in Ca 2+ efflux, independent of time exposure. Ca2+ channel blockers Co2+, La3+, and verapamil inhibited Pb2+-induced flux. The sarco/endoplasmic reticulum Ca 2+-ATPase pump inhibitors, thapsigargin and cyclopiazonic acid, both elicited a Ca2+ efflux reflecting inhibition of ER pumps and [Ca2+]i release. Furthermore, Pb2+ evoked a moderate and sustained elevation in thapsigargin-stimulated Ca 2+ efflux. For morphological evidence that Pb2+ can mobilize [Ca 2+]i, potassium pyroantimonate (KPA) cytochemistry of bag cells were analyzed. 2% KPA resulted in widespread electron-dense precipitates. 10 mM EGTA + KPA or 200 μM Pb2+ + KPA both produced marked reductions of precipitates in neurons. X-ray microanalysis confirmed antimony (Sb) in precipitates but could not separate the overlapping Ca2+-Sb spectral peaks. However, reduced precipitates in EGTA-incubated cells indicate presence of Ca2+ in intracellular precipitates observed. No apparent pathological changes were correlated to Pb2+ exposure. The effects of Pb2+ on [Ca2+]i using the fluorescent Ca2+ indicator, chlortetracycline (CTC), was examined. Control neurons incubated in 10 μM CTC demonstrated extensive yellow-green fluorescence while reduced fluorescence intensities were seen in cells exposed to 200 μM Pb2+. Multi-sized punctate fluorescence were observed along the perimeter and sometimes, throughout the soma. No neuronal autofluorescence nor neuritic fluorescence in control and Pb2+-exposed cells were detected. Average fluorescence intensities between control and Pb2+-exposed neurons were statistically significant (P < 0.0005). Collectively, these results are consistent with the hypothesis that Pb 2+ perturbs Ca2+ homeostasis via mobilization of [Ca 2+]i. Pb2+ operates through Ca2+ transport pathways as shown by changes in transmembrane Ca 2+ flux, in KPA precipitate reactions, and in CTC fluorescence.