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

Digital Commons Network™

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

Open Access Dissertations

Discipline
Institution
Keyword
Publication Year

Articles 2611 - 2640 of 3760

Full-Text Articles in Entire DC Network

Study Of Particle Deposition In Human Airway Models, Guosen Yue Jan 2001

Study Of Particle Deposition In Human Airway Models, Guosen Yue

Open Access Dissertations

In this dissertation, the deposition of particles in human airway models is studied. The dissertation consists of three parts: In the first part, an analytical model of particle nasal airway deposition by diffusion considering effects of both laminar and turbulent flows is proposed. It appears in the literature that neither laminar nor turbulent analytical models alone works well for the entire range of diffusion parameters. A simplified turbulent particle diffusion equation is first developed and then a new combined turbulent/laminar diffusion model is proposed. The results predicted from the new model show improved accuracy when compared with available experimental data …

Go to article

Analysis Of A Proposed Model For Detection Of Magnetic Fields By Biological Systems, Su-Hsiu Wu Jan 2001

Analysis Of A Proposed Model For Detection Of Magnetic Fields By Biological Systems, Su-Hsiu Wu

Open Access Dissertations

Numerous reports have indicated that some biological effects of relatively weak alternating magnetic fields depend upon the presence and magnitude of a parallel-directed static magnetic field. One explanation of these phenomena is parametric resonance mechanism, originally proposed by Lednev and also applied in modified form by Blackman and Blanchard. The mechanism, as formulated by Lednev, involves the Zeeman splitting of infrared vibration levels of Ca2+ ions within proteins such as calmodulin. It is shown that this model can be formulated using mostly classical physics. In this formulation the linear vibration path of an oscillating ion is set into uniform rotation …

Go to article

Physicochemical And Microstructural Changes In Minced Fish Muscles As Affected By Cryoprotectants, Peizhi Lian Jan 2001

Physicochemical And Microstructural Changes In Minced Fish Muscles As Affected By Cryoprotectants, Peizhi Lian

Open Access Dissertations

Alginate, carrageenan, soy protein concentrate (SPC), sodium tripolyphosphate (STPP), and sorbitol were chosen as potential cryoprotectants. Their effects on physicochemical and sensory properties of frozen red hake (Urophycis chuss) and Alaska pollock (Theragra chalcogramma ) mince at ˆ’20 °C for 17 weeks were investigated. The mince was mixed with 0.3% STPP, 4% sorbitol and either 0.2-0.4% alginate, 0.2-0.4% iota-carrageenan, or 4% SPC. Changes in texture, microstructure, and profiles of proteins, free amino acids and lipids of fresh and frozen mince were evaluated. The addition of alginate, STPP, and sorbitol significantly improved the dispersibility of uncooked red hake mince with reduced …

Go to article

β-Glucuronidase Assay For The Detection Of Escherichia Coli In Foods, Seref Tagi Jan 2001

β-Glucuronidase Assay For The Detection Of Escherichia Coli In Foods, Seref Tagi

Open Access Dissertations

Enzyme assays were developed for the measurement of β-D-glucuronide (GUS) as a rapid detection method for E. coli in food. A fluorescent assay utilizing 4-methylumbelliferyl-β-D-glucuronide as substrate was optimized and tested with growth cultures of E. coli. A relationship between E. coli and the level of GUS activity was established. A chemiluminescent assay using a 1,2-dioxetene derivative as substrate was compared to the fluorescent assay, and was found to be 10x more sensitive. Anti-E. coli GUS antibodies were covalently immobilized on magnetic beads and used in a 30 min immunocapture method. GUS was recovered from E. coli grown at 37°C …

Go to article

Experimental Studies Of Microstructural Evolution In Mixed Cationic/Anionic Surfactant Systems, Yashen Xia Jan 2001

Experimental Studies Of Microstructural Evolution In Mixed Cationic/Anionic Surfactant Systems, Yashen Xia

Open Access Dissertations

Various aqueous mixtures of the oppositely charged surfactants combine to form vesicles at a certain mixing ratio. The evolution of aggregate microstructures as well as the dynamics of the formation of vesicles starting with different surfactant pairs of aqueous solutions based on compositions, different molecular structures, tail lengths and addition of monovalent salt has been investigated. The growth of the aggregates during the first two hours after mixing, measured by dynamic light scattering, was found to be sensitive to compositions, tail structures and tail lengths of surfactant pairs, but not to addition of monovalent salt. The morphology of intermediate state …

Go to article

Anoxia Tolerance And Recovery In Freshwater And Marine Turtles, Malia Lois Schwartz Jan 2001

Anoxia Tolerance And Recovery In Freshwater And Marine Turtles, Malia Lois Schwartz

Open Access Dissertations

Anoxia tolerance and recovery in freshwater and marine turtles were investigated. This study quantified several factors thought to influence anoxia tolerance and recovery, including body size, feeding history, season, the turtle's sex, and repetitive entrapment. In Chrysemys picta bellii, body size had little effect on anoxic metabolism, although small turtles regained normal behavior more rapidly and exhibited no lag in lactate clearance. Feeding history also had little effect on anoxia tolerance, but turtles that had recently fed recovered more slowly than fasted animals. There were no differences between the sexes in anoxia tolerance; however, females recovered faster behaviorally. The lack …

Go to article

Cadmium Toxicity And Random Motility Studies Using Marine Dinoflagellates, Edwin Li Jan 2001

Cadmium Toxicity And Random Motility Studies Using Marine Dinoflagellates, Edwin Li

Open Access Dissertations

The marine biota is exposed to heavy metal residues of industrial and agricultural processes. The effects of these metals on phytoplankton are of particular interest because they represent the first link in the food chain and are able to transfer the metal to higher trophic levels. Members of the phytoplankton population include the diverse community of flagellated unicellular, mostly photosynthetic, microorganisms called dinoflagellates. The effects of cadmium (Cd) on the growth of two marine dinoflagellates Scrippsiella narragansettensis and Heterocapsa triquetra were measured under different medium composition. To investigate the role of metal speciation, experiments were carried out in media prepared …

Go to article

Remote Sensing Of Bio-Optical Water Types, Phytoplankton Seasonality, And Algal Pigments In Ocean Margin Waters, Paula Susan Bontempi Jan 2001

Remote Sensing Of Bio-Optical Water Types, Phytoplankton Seasonality, And Algal Pigments In Ocean Margin Waters, Paula Susan Bontempi

Open Access Dissertations

A frontal edge detection algorithm was applied to remotely sensed ocean color satellite data to identify incorrect retrievals of phytoplankton chl a concentrations, and refine estimates of primary producer abundance in bio-optically complex ocean margin waters. Improvement of the remotely sensed biological signal will facilitate establishment of more accurate daily to decadal phytoplankton spatial patterns in these waters, and enable prediction of phytoplankton blooms or features from space. Spatial patterns of chlorophyll a (chl a) and water-leaving radiance (Lwn) from 1998 SeaWiFS (Sea-Viewing Wide Field-of-View Sensor) images were examined from ocean margin waters off the southeastern continental United States (SEC). …

Go to article

Death And Identity: Consumer Behavior In Asante Death Rituals, Samuel Kwaku Bonsu Jan 2001

Death And Identity: Consumer Behavior In Asante Death Rituals, Samuel Kwaku Bonsu

Open Access Dissertations

Poorer societies have been ignored in scholarly dialogue on consumer behavior and consumption. The globalization of markets and consumption makes it imperative for marketing and consumer researchers to pay attention to these societies. This dissertation, therefore, explored the dynamics of consumer product decisions and how choices are used by the bereaved to negotiate identities for themselves and the deceased among the Asante people of Ghana. The study focused on the increasingly important role of the ritualized consumption of death ritual products among the Asante people of Ghana. West Africa, and examined the socio-cultural sources of influence on death product choices …

Go to article

Theoretical And Experimental Study Of Fiber-Optic Fluorescence Immunosensors, He Cao Jan 2001

Theoretical And Experimental Study Of Fiber-Optic Fluorescence Immunosensors, He Cao

Open Access Dissertations

This dissertation investigates the optical detection of antigens (in this case, food pathogens such as Salmonella) with fiber-optic immunosensors. The major techniques used for this optical detection include: (1) Linking the antigens to some physical tracers that can be optically detected; (2) Collecting and transmitting the optical signal to an optical detector. From an optical point of view, the problem is a nonimaging-optics problem to collect a fluorescent signal from an extended Lambertian source and deliver it to an optical detection system with maximum energy transfer and distinct wavelength separation. A raytrace model of the optical detection system was used …

Go to article

Piety And Intolerance: A Rhetorical Inquiry Into The Constituting Of Christian Fundamentalist Identity, Mary K. Cardinale Jan 2001

Piety And Intolerance: A Rhetorical Inquiry Into The Constituting Of Christian Fundamentalist Identity, Mary K. Cardinale

Open Access Dissertations

"Piety and Intolerance: A Rhetorical Inquiry Into the Constituting of Christian Fundamentalist Identity" explores the connection between fundamentalist texts and the promotion of prejudice--prejudice defined as intolerance, discrimination, and "negative intergroup attitude[s]" toward outsiders. Studies suggest a relationship between religious fundamentalism and prejudice; however, no study has found conclusively what links them. In response, this study analyzes and interprets passages from two fundamentalist texts in order to locate link/s between the texts' rhetorical elements and their effects on constituting an exclusive fundamentalist identity that positions outsiders as God's enemies. I argue that epideictic rhetoric and the enthymeme, employed as a …

Go to article

Gender Roles And Science Beliefs And Their Relationship To Science Interest, Judith Jean Paolucci Jan 2001

Gender Roles And Science Beliefs And Their Relationship To Science Interest, Judith Jean Paolucci

Open Access Dissertations

This study investigated adolescents' views about the nature of science (NOS) and conceptions of their gender identities, and revealed whether these conceptions and views are related to their science interest. Participants were 566 high school students enrolled in chemistry courses at three high schools in a New England state. A questionnaire was used to assess participants' science interest, gender role perceptions, and views about science, as well as to provide background and math and science achievement data. The study found that while student scores of NOS understanding did not differ by gender, some significant differences were noted on the student …

Go to article

Development, Validation And Factorial Invariance Of Transtheoretical Model Measures For Recovery From Anorexia Nervosa And Bulimia Nervosa, Patricia Janet Jordan Jan 2001

Development, Validation And Factorial Invariance Of Transtheoretical Model Measures For Recovery From Anorexia Nervosa And Bulimia Nervosa, Patricia Janet Jordan

Open Access Dissertations

The purpose of this study was to advance understanding of the self-change process in recovery from anorexia nervosa (AN) and bulimia nervosa (BN) through: (a) development of a staging instrument for recovery from BN; (b) development of TTM-based measures, including decisional balance, self-efficacy, and processes of change; (c) invariance testing of these measures across AN and BN subsamples; and (d) characteristic description of individuals at each stage of change. The sample (N = 427) was composed of AN subgroup (n = 278) and BN subgroup (n = 149) who completed questionnaires measuring all constructs of the TTM, as well as …

Go to article

Nonviolence Training Program Evaluation, Maram Hallak Jan 2001

Nonviolence Training Program Evaluation, Maram Hallak

Open Access Dissertations

There has been much recent attention given to conflict resolution and nonviolence training programs in the face of problems of violence in our society. The Center for Nonviolence and Peace Studies at the University of Rhode Island was founded to provide nonviolence training to students of the university and community members. The purpose of this study was to evaluate the effectiveness of the Center's Nonviolence Training Program, based on Martin Luther King's approaches, designed to teach participants nonviolence methods as a way of life. A qualitative study gathered information and established the overall expectations of the parties involved. Focus groups …

Go to article

The Global Stability, Boundedness, And Periodicity Character Of Certain Difference Equations, Michael Alexander Radin Jan 2001

The Global Stability, Boundedness, And Periodicity Character Of Certain Difference Equations, Michael Alexander Radin

Open Access Dissertations

We study the global stability, the boundedness nature, and the periodic character of the positive solutions of the difference equation [special characters omitted]where the parameters α and β are positive real numbers and the initial conditions x−1 and x0 are arbitrary non-negative real numbers. This problem was proposed by Dr. Richard Levins of the Harvard School of Public Health as a population model in Mathematical Biology. We consider α to be the immigration rate and β to be the population growth rate. We will also investigate the periodic character and the boundedness nature of all positive solutions of following two …

Go to article

Aspects Of The Physiology Of Early Juvenile Cod (Gadus Morhua L.) And Haddock (Melanogrammus Aeglefinus L.), Myron Arms Peck Jan 2001

Aspects Of The Physiology Of Early Juvenile Cod (Gadus Morhua L.) And Haddock (Melanogrammus Aeglefinus L.), Myron Arms Peck

Open Access Dissertations

In this research, the effects of temperature, body size, and/or feeding level on a variety of bioenergetic parameters in early (age-0) juveniles of both Atlantic cod (Gadus morhua L.) and haddock (Melanogrammus aeglefinus L.) were quantified. Bioenergetic parameters were measured at temperatures (5, 8, 12, and 15°C) experienced by field fish, using a range in fish sizes (3 to 13 cm TL) encompassing the first year of juvenile growth. In the first study, the relationship between cod and haddock growth rate (GI) and feeding-level (C) was quantified at different temperatures. The shape of the GI - C relationship and growth …

Go to article

Honey Amylase And The Effect In Starch-Containing Foods, Sibel Babacan Jan 2001

Honey Amylase And The Effect In Starch-Containing Foods, Sibel Babacan

Open Access Dissertations

Honey amylase was evaluated for potential to degrade food starch and cause viscosity loss. Honey was assayed for amylase activity with diastase number (DN). A viscosity assay, developed with unmodified waxy maize starch, measured rate of viscosity decrease (RVD) by honey amylase. The relationship between DN and RVD was linear (R2 = 0.98). Modified waxy maize starches showed resistance to honey amylase. Heat treatment at 85 °C reduced the amylase activity in honey, but confirmed enzyme heat resistance. Optimum pH for honey amylase was confirmed at pH 5.3-5.6. Lower pH was effective at decreasing enzyme activity in both pure starch …

Go to article

Optimal Exploitation Of Atlantic Herring Stocks In United States Of America: Bioeconomic Model For Atlantic Herring, Jung-Hee Cho Jan 2001

Optimal Exploitation Of Atlantic Herring Stocks In United States Of America: Bioeconomic Model For Atlantic Herring, Jung-Hee Cho

Open Access Dissertations

The Atlantic herring, Clupea harengus, is a pelagic species widely distributed in continental shelf waters along the Atlantic coast from the Gulf of Maine to Cape Hatteras. Even though the herring fishery is a relatively small portion of the East coast fishing industry, herring is important as bait for lobster fisheries and a component of the food web of the Northwest Atlantic Ocean. Currently, the herring resource is in an under-exploited state and catches are less than one-third of Maximum Sustainable Yield. The herring fishery is reviewed in term of markets, resource, and management. Because herring is very vulnerable to …

Go to article

A Synthetic Approach To Forecasting Fleet Costs And Earnings In The Northeast Regions Of The United States, Philippe D. Lallemand Jan 2001

A Synthetic Approach To Forecasting Fleet Costs And Earnings In The Northeast Regions Of The United States, Philippe D. Lallemand

Open Access Dissertations

This study describes the New England Otter Trawl Fishery between 1982 and 1998 and the potential economic impacts of regulations on the Northeastern Multispecies Groundfish Fishery (MGF). The study uses primary data collected by the author and secondary data obtained from the National Marine Fisheries Service (NMFS). This research required extensive econometric analysis of both value landed and cost data. The landed value is influenced by the vessel's physical characteristics, port of landing, seasonal choices of fishing gear-species combinations, days at sea and distance from shore, and the captain's skill (also referred to as the "skipper effect"). The vessel-cost model …

Go to article

Impedance Analysis Of An Enhanced Piezoelectric Biosensor, Gi-Ho Kim Jan 2001

Impedance Analysis Of An Enhanced Piezoelectric Biosensor, Gi-Ho Kim

Open Access Dissertations

This study investigated the usefulness and characteristics of a five-megahertz quartz crystal resonator oscillating in a thickness-shear mode as a sensor of biological pathogens such as Salmonella typhimurium . An impedance analyzer measured the impedance of the oscillating quartz crystal, which determined all mechanical properties of the oscillating quartz and its immediate environment. In this study, the impedance behavior of the bare crystal was characterized in air and in potassium phosphate buffer solution. The potassium phosphate buffer was a Newtonian liquid. The resonance frequency of the oscillating quartz shifted down about 900 Hz by contacting with the buffer. An immobilized-antibody …

Go to article

Contaminants In Narragansett Bay Sediments, Paul Christian Hartmann Jan 2001

Contaminants In Narragansett Bay Sediments, Paul Christian Hartmann

Open Access Dissertations

Three interrelated studies using sediment samples collected at 41 stations in 1997-98 and sediment trap samples collected from 14 stations in 2000 are presented. The concentration of LABs, PAHs, TPHs, PCBs, DDTs, and chlordanes in the surface sediments (top 2 cm) were highest in the urban rivers at the head of the bay and decreased down the East and West Passages. Overall, the data indicate that sediment PAHs, PCBs and DDTs may have a significant impact on the benthos of Narragansett Bay. The ratio of PAH to TPH, as well as the alkyl homolog distribution for PAHs, indicates that petrogenic …

Go to article

Numerical Modeling Of Estuarine Transport, Water Quality, And The Impact Of Shrimp Mariculture In The Rio Chone Estuary, Ecuador, Diana Lynn Stram Jan 2001

Numerical Modeling Of Estuarine Transport, Water Quality, And The Impact Of Shrimp Mariculture In The Rio Chone Estuary, Ecuador, Diana Lynn Stram

Open Access Dissertations

The Rio Chone estuary in Ecuador has been heavily impacted by a range of anthropogenic impacts, particularly the conversion of mangrove forests to shrimp mariculture ponds. The combination of seasonal river flow, climate forcing and the influx of highly saline pond effluents have created a slow circulation regime in the estuary, especially during the dry season when the estuary can undergo a salinity inversion from mouth to head. Both shrimp production and water quality in the estuary have declined, specifically in the upper regions of the estuary where low dissolved oxygen is often a problem. A combined physical and biological …

Go to article

Cultural Conditioning And Mother/Daughter Conflicts In The Development Of Identity And Voice: The Autobiographical Fiction Of Dorothy Allison, Wan-So Pak, And Maxine Hong Kingston, Eunjoo Woo Jan 2001

Cultural Conditioning And Mother/Daughter Conflicts In The Development Of Identity And Voice: The Autobiographical Fiction Of Dorothy Allison, Wan-So Pak, And Maxine Hong Kingston, Eunjoo Woo

Open Access Dissertations

This dissertation examines the fictionalized autobiographies of three women writers from different cultures and ethnicities and analyzes the development of female identity, subjectivity, and voice through the mother/daughter relationships in Dorothy Allison's Bastard Out Of Carolina, Wan-So Pak's The Naked Tree and Mother's Stake 1, and Maxine Hong Kingston's The Woman Warrior. These three women writers introduce the mother/daughter conflicts and suggest ways to reconcile with each other or to solve their problems in their particular and cultural contexts. Also, in spite of their cultural differences, all three women writers share their belief that the process of the daughter's search …

Go to article

Childhood Trauma, Family Functioning And Adult Health: Protective Factors As Mediating Variables, Jennifer Ann Morrow Jan 2001

Childhood Trauma, Family Functioning And Adult Health: Protective Factors As Mediating Variables, Jennifer Ann Morrow

Open Access Dissertations

The current study looked at the plausibility of two theories: Social Cognitive Theory and Survivor Theory to explain the interrelationships between childhood trauma, family functioning, protective factors, and adult health. The interrelationships among these constructs were explored with a sample of 451 undergraduate students . Structural equation models revealed that there is a mediational relationship between childhood trauma and health through social support. This relationship was similar for men and women. Cluster analysis and multivariate analysis of covariance revealed that individuals with high levels of all the childhood traumas (physical, psychological, and sexual abuse) have significantly more physical and psychological …

Go to article

Biological Vibrational Spectroscopy: From A Cellular To A Sub-Cellular Level, Scott Wade Huffman Jan 2001

Biological Vibrational Spectroscopy: From A Cellular To A Sub-Cellular Level, Scott Wade Huffman

Open Access Dissertations

The prevention of fatality from disease has long been a goal of medical and food sciences. In the field of cervical cancer research, the early detection of cancerous cells via Pap smear screening has proven to be an effective tool in combating cancer related deaths. However the sheer magnitude of Pap smears needing diagnosis has led to a decrease in efficiency and accuracy. In a different field, a similar problem persists. The goal of food science is to provide mass quantities of food that is safe for consumption. The amount of food prepared for dispersal is staggering in that it …

Go to article

Hypoglycemic Drug Utilization And Adherence To Prescribed Regimens: A Pharmacoepidemiologic Study Using Retail Pharmacy Data, Stephen Jon Kogut Jan 2001

Hypoglycemic Drug Utilization And Adherence To Prescribed Regimens: A Pharmacoepidemiologic Study Using Retail Pharmacy Data, Stephen Jon Kogut

Open Access Dissertations

Diabetes mellitus is a highly prevalent condition, afflicting an estimated 6% of the United States adult population. It is also a complex condition to manage. Dietary, exercise, and drug therapies are essential for reducing the risk of various neurologic and vascular diseases related to disease progression. Tight control of blood glucose as achieved through intensive pharmacologic therapy has been shown to decrease the risk of developing several types of diabetic complications. Success in achieving tight blood glucose control is contingent upon adherence to the prescribed hypoglycemic drug regimen , a behavior known to often be sub-optimal. The objectives of this …

Go to article

Patterns And Correlates Of Landscape Change In Northern Thailand, Jarunee Nugranad Jan 2000

Patterns And Correlates Of Landscape Change In Northern Thailand, Jarunee Nugranad

Open Access Dissertations

No abstract provided.

Go to article

Studies On The Pedal Gland And Pedal Epithelium Of The Protobranchiate Bivalvia, Heather Bennett Jan 2000

Studies On The Pedal Gland And Pedal Epithelium Of The Protobranchiate Bivalvia, Heather Bennett

Open Access Dissertations

No abstract provided.

Go to article

Relating Objective And Subjective Measures Of Water Quality In The Travel Cost Method: An Application To The Peconic Estuary System, Jerry Diamantides Jan 2000

Relating Objective And Subjective Measures Of Water Quality In The Travel Cost Method: An Application To The Peconic Estuary System, Jerry Diamantides

Open Access Dissertations

No abstract provided.

Go to article

Systematics, Ecology, Feeding Biology, And Reproduction Of Polydorids (Polychaeta: Spionidae) Associated With Hermit Crabs From The Indo-West Pacific, Jason D. Williams Jan 2000

Systematics, Ecology, Feeding Biology, And Reproduction Of Polydorids (Polychaeta: Spionidae) Associated With Hermit Crabs From The Indo-West Pacific, Jason D. Williams

Open Access Dissertations

No abstract provided.

Go to article

First Prev Next Last