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Title: Algebraic and combinatorial aspects of group factorizations.
Creator: Bozovic, Vladimir., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: The aim of this work is to investigate some algebraic and combinatorial aspects of group factorizations. The main contribution of this dissertation is a set of new results regarding factorization of groups, with emphasis on the nonabelian case. We introduce a novel technique for factorization of groups, the so-called free mappings, a powerful tool for factorization of a wide class of abelian and non-abelian groups. By applying a certain group action on the blocks of a factorization, a number...
Show moreThe aim of this work is to investigate some algebraic and combinatorial aspects of group factorizations. The main contribution of this dissertation is a set of new results regarding factorization of groups, with emphasis on the nonabelian case. We introduce a novel technique for factorization of groups, the so-called free mappings, a powerful tool for factorization of a wide class of abelian and non-abelian groups. By applying a certain group action on the blocks of a factorization, a number of combinatorial and computational problems were noted and studied. In particular, we analyze the case of the group Aut(Zn) acting on blocks of factorization of Zn. We present new theoretical facts that reveal the numerical structure of the stabilizer of a set in Zn, under the action of Aut(Zn). New algorithms for finding the stabilizer of a set and checking whether two sets belong to the same orbit are proposed.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/107805
Subject Headings: Physical measurements, Mapping (Mathematics), Combinatorial enumeration problems, Algebra, Abstract
Format: Document (PDF)

Title: Visual discrimination by C57BL/6J mice in water maze tasks: does size really matter?.
Creator: Buerger, Eric D., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: When interpreting how an animal "learns" discrimination tasks, strain capabilities must be considered, and it should be shown that they comprehend the task in a manner consistent with the given interpretation. A novel visual-discrimination (VD) task for relative-size-relations was used to examine visual cue use in C57BL/6J mice, which are shown to have biologically good vision and neurologically intact memory for VD tasks. Results suggest C57BL/6J strain may not be fully capable of relative...
Show moreWhen interpreting how an animal "learns" discrimination tasks, strain capabilities must be considered, and it should be shown that they comprehend the task in a manner consistent with the given interpretation. A novel visual-discrimination (VD) task for relative-size-relations was used to examine visual cue use in C57BL/6J mice, which are shown to have biologically good vision and neurologically intact memory for VD tasks. Results suggest C57BL/6J strain may not be fully capable of relative cue-size associations or even object recognition-based on a water maze VD task. This is in contrast to previous studies suggesting this mice strain is quite strong in visual skills and on VD tasks. Additionally, cue size and/or cue-pairings do appear to influence specific directional preferences or stereotyped behaviors as trainings continued, and these strategies shifted during novel probes. Future studies should assess how mice discriminate between objects and test rat's capabilities on this task.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/165670
Subject Headings: Visual discrimination, Form perception, Animal behavior, Simulation methods, Animals, Adaptation, Simulation methods
Format: Document (PDF)

Title: Choosing and using tools: type of prior experience and task difficulty influence preschoolers' choices and actions.
Creator: Gardiner, Amy K., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Two and 3 year-old children's understanding of tool affordances was investigated by measuring their tool choice decisions and tool use behaviors. Children attempted six toy retrieval tasks of three different levels of structural complexity. Children were assigned to one of four conditions in which exposure to task materials varied according to the way in which the information was presented: no experience / no observation, experience only, observation only, and experience and observation....
Show moreTwo and 3 year-old children's understanding of tool affordances was investigated by measuring their tool choice decisions and tool use behaviors. Children attempted six toy retrieval tasks of three different levels of structural complexity. Children were assigned to one of four conditions in which exposure to task materials varied according to the way in which the information was presented: no experience / no observation, experience only, observation only, and experience and observation. Three year- olds consistently made more correct choices and used more working tools successfully than 2-year-olds. Tool choice was affected primarily by task difficulty and age. Tool use was influenced by task difficulty, order of task difficulty, age, and condition. The observation condition was most beneficial to children, while experience was least helpful, particularly for tasks at the hard level of difficulty.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/165940
Subject Headings: Learning, Psychology of, Developmental psychology, Educational tests and measurements, Constructivism (Education)
Format: Document (PDF)

Title: Spatial and trophic ecology of the sawtooth eel, Serrivomer beanii, a biomass-dominant bathypelagic fish over the northern Mid-Atlantic ridge.
Creator: Geidner, Megan E., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The role of Serrivomer beanii in bathypelagic food webs is poorly known, but abundance and biomass estimates from the 2004 G.O. Sars MAR-ECO Expedition suggest it to have a high level of importance. MAR-ECO, a Census of Marine Life field project, has allowed us to increase our knowledge of S. beanii through spatial analysis, including the congeneric species Serrivomer lanceolatoides, and trophic analysis. Serrivomer beanii abundance and biomass exhibited a decreasing trend along the northern...
Show moreThe role of Serrivomer beanii in bathypelagic food webs is poorly known, but abundance and biomass estimates from the 2004 G.O. Sars MAR-ECO Expedition suggest it to have a high level of importance. MAR-ECO, a Census of Marine Life field project, has allowed us to increase our knowledge of S. beanii through spatial analysis, including the congeneric species Serrivomer lanceolatoides, and trophic analysis. Serrivomer beanii abundance and biomass exhibited a decreasing trend along the northern Mid-Atlantic Ridge from north to south. In terms of size, S. beanii was found to increase as distance from the ridge decreased, suggesting a topographic aggregation strategy. The diet of S. beanii consisted of crustaceans, cephalopods, and teleosts. The trophic results of this study reveal a likely "alternative" trophic pathway in the deep mid-North Atlantic, and perhaps other, bathypelagic ecosystems: higher trophic-level predators are supported by micronektonic invertebrates as primary prey.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/165941
Subject Headings: Plankton, Ecology, Coral reef animals, Ecology, Deep sea biology
Format: Document (PDF)

Title: Molecular mechanisms of neuroprotection in the anoxia tolerant freshwater turtle.
Creator: Kesaraju, Shailaja., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Cardiac ischemia, stroke and some neurodegenerative disorders are all characterized by cell damage and death due to low oxygen levels. Comparative studies show that anoxia tolerant model systems present a unique opportunity to study "survival" instead of death in the complete absence of oxygen. The freshwater turtle (Trachemys scripta elegans) is unique in its ability to survive total oxygen deprivation for hours to days, as well as reoxygenation insult after anoxia. The broad objective of...
Show moreCardiac ischemia, stroke and some neurodegenerative disorders are all characterized by cell damage and death due to low oxygen levels. Comparative studies show that anoxia tolerant model systems present a unique opportunity to study "survival" instead of death in the complete absence of oxygen. The freshwater turtle (Trachemys scripta elegans) is unique in its ability to survive total oxygen deprivation for hours to days, as well as reoxygenation insult after anoxia. The broad objective of this study is to understand the modulation of key molecular mechanisms involving stress proteins and VEGF that offer neuroprotection and enhance cell survival in the freshwater turtle through anoxia and reoxygenation. In vivo analyses have shown that anoxia induced stress proteins (Hsp72, Hsp60, Grp94, Hsp60, Hsp27, HO-1); modest changes in the Bcl2/Bax ratio and no change in cleaved caspase-3 expression suggesting resistance to neuronal damage. These results were corroborated with immunohistochemical evidence indicating no damage in turtle brain when subjected to the stress of anoxia and A/R. To understand the functional role of Hsp72, siRNA against Hsp72 was utilized to knockdown Hsp72 in vitro (neuronally enriched primary cell cultures established from the turtle). Knockdown cultures were characterized by increased cell death associated with elevated ROS levels. Silencing of Hsp72 knocks down the expression of Bcl2 and increases the expression of Bax, thereby decreasing the Bcl2/Bax ratio. However, there was no increase in cytosolic Cytochrome c or the expression levels of cleaved Caspase-3. Significant increase in AIF was observed in the knockdown cultures that increase through anoxia and reoxygenation, suggesting a caspase independent pathway of cell death., Expression of the master regulator of hypoxia, HIF1 alpha and its target gene, VEGF, were analyzed at the mRNA and protein levels. The results showed no significant increase in HIF-1 alpha levels but anoxia VE GF The levels of stress proteins and VEGF returned to control levels during reoxygenation suggesting robust ROS protection mechanisms through reoxygenation. The present study thereby emphasizes Trachemys scripta as an advantageous model to examine anoxia and reoxygenation survival without major damage to the brain due to it's modulation of molecular mechanisms.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/165943
Subject Headings: Turtles, Physiology, Anoxemia, Proteins, Chemical modification, Oxygen, Physiological effect, Molecular neurobiology
Format: Document (PDF)

Title: Dispositionally speaking, what you see is what you get.
Creator: Shuhi, Robert P., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Many studies have been devoted to investigating the process by which individuals make dispositional attributions about the people that they encounter. Typically, individuals are more likely to seek future interactions with target individuals if those target individuals have a positive or rewarding disposition. Interactions with target individuals possessing negative or punishing dispositions reduce the likelihood that target individual will be selected for future interactions. An initial...
Show moreMany studies have been devoted to investigating the process by which individuals make dispositional attributions about the people that they encounter. Typically, individuals are more likely to seek future interactions with target individuals if those target individuals have a positive or rewarding disposition. Interactions with target individuals possessing negative or punishing dispositions reduce the likelihood that target individual will be selected for future interactions. An initial false positive trait ascription will be self-correcting with future interactions. An initial false negative trait label will likely remain stable if future interactions are not forced. The importance of quick accurate disposition identification carries important evolutionary implications as well as normal-life implications. Results from an experiment support the ability of subjects to accurately identify the true trait of target individuals with limited dispositional information.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/165945
Subject Headings: Attribution (Social psychology), Interpersonal communication, Philosophy, Social interaction, Social perception
Format: Document (PDF)

Title: No bones about it (or are there?): evaluating markedness constraints on structural representations of the phonology skeleton.
Creator: Causey, Kayla B., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Linguistic research suggests that speakers represent syllable structure by a CV-frame. CVC syllables are more frequent than VCC ones. Further, the presence of VCC syllables in a language asymmetrically implies the presence of CVC syllables. These typological facts may reflect grammatical constraints. Alternatively, people's preferences may be due solely to their sensitivity to the statistical properties of sound combinations in their language. I demonstrate that participants in an auditory...
Show moreLinguistic research suggests that speakers represent syllable structure by a CV-frame. CVC syllables are more frequent than VCC ones. Further, the presence of VCC syllables in a language asymmetrically implies the presence of CVC syllables. These typological facts may reflect grammatical constraints. Alternatively, people's preferences may be due solely to their sensitivity to the statistical properties of sound combinations in their language. I demonstrate that participants in an auditory lexical decision task reject VCC nonwords faster than CVC nonwords, suggesting that the marked VCC syllables are dispreferred relative to CVC syllables. In a second experiment, I show that people are also sensitive to the distribution of these frames in the experiment. Findings indicate that syllable structure is represented at the phonological level, that individuals have preferences for certain syllables, and that these preferences can not be accounted for by the statistical properties of the stimuli.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/166449
Subject Headings: Grammar, Comparative and general, Phonology, Phonetics, Computational linguistics, Universals (Linguistics), Learning, Psychology of
Format: Document (PDF)

Title: Discounting the role of causal attributions in the ANOVA model of attribution.
Creator: Hakala, Kori A., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: For years attribution research has been dominated by the ANOVA model of behavior which proposes that people construct their dispositional attributions of others by carefully comparing and weighing all situational information using mental computations similar to the processes used by researchers to analyze data. A preliminary experiment successfully determined that participants were able to distinguish differences in variability assessed across persons (high vs. low consensus) and across...
Show moreFor years attribution research has been dominated by the ANOVA model of behavior which proposes that people construct their dispositional attributions of others by carefully comparing and weighing all situational information using mental computations similar to the processes used by researchers to analyze data. A preliminary experiment successfully determined that participants were able to distinguish differences in variability assessed across persons (high vs. low consensus) and across situations (high vs. low distinctiveness). Also, it was clear that the subjects could evaluate varying levels of situational constraint. A primary experiment administered to participants immediately following the preliminary study determined that participants grossly under-utilized those same variables when making dispositional attributions. Results gave evidence against the use of traditional ANOVA models and support for the use of the Behavior Averaging Principle of Attribution.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/166450
Subject Headings: Social sciences, Statistical methods, Analysis of variance, Data processing, Mathematical statistics, Attribution (Social psychology)
Format: Document (PDF)

Title: Differentiating decomposition rates within the ridge-slough microtopography of the central Florida Everglades.
Creator: Van der Heiden, Sheryl R., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The relative rates of detrital decomposition in four vegetation communities within the Everglades' ridge-slough microtopography were evaluated during two trials. Litterbags with community-specific detritus in proportion to each community's composition were put into the four communities; namely, submerged marsh, emergent marsh, short Cladium ridge, and tall Cladium ridge. These litterbags were paired with litterbags containing control leaf litter from Chrysobalanus icaco and Salix caroliniana...
Show moreThe relative rates of detrital decomposition in four vegetation communities within the Everglades' ridge-slough microtopography were evaluated during two trials. Litterbags with community-specific detritus in proportion to each community's composition were put into the four communities; namely, submerged marsh, emergent marsh, short Cladium ridge, and tall Cladium ridge. These litterbags were paired with litterbags containing control leaf litter from Chrysobalanus icaco and Salix caroliniana during the wet and dry season trials, respectively. No regional differences in decomposition were shown, but there were significant differences across communities, attributed to the initial C:N ratio of the detritus, with the fastest decomposition occurring in the deepest submerged marsh followed by emergent marsh, and the shallower ridge communities had equally slower decomposition. Additionally, both controls followed the same pattern. Thus, decomposition contributes to an active self-maintenance mechanism within the vegetation communities which ultimately helps to conserve the ridges and sloughs.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/166456
Subject Headings: Biogeochemistry, Surfaces (Technology), Measurement, Vegatation dynamics, Mathematical models, Wetland ecology
Format: Document (PDF)

Title: Selection of canals and ditches as foraging habitat by wood s7374torks (Mycteria americana).
Creator: Van Os, Eleanor K., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: A challenge to ensure the health of wading bird populations is to have a better understanding of the altered habitats that we must now consider part of their natural history. Throughout their range endangered Wood Storks (Mycteria americana) have been reported to forage in ditches, a disparate category of linear man-made waterways. In a 52-kmP 2 P study area on the east coast of central Florida, the characteristics of hydrologically diverse ditches were quantified, and their use by Wood...
Show moreA challenge to ensure the health of wading bird populations is to have a better understanding of the altered habitats that we must now consider part of their natural history. Throughout their range endangered Wood Storks (Mycteria americana) have been reported to forage in ditches, a disparate category of linear man-made waterways. In a 52-kmP 2 P study area on the east coast of central Florida, the characteristics of hydrologically diverse ditches were quantified, and their use by Wood Storks documented during their non-breeding season. Logistic regression analyses were carried out using the ditch characteristics as independent variables and Wood Stork presence/absence as the dependent variable. This study confirms the use of these marginal wetlands, and identifies the significance of emergent vegetation on the foraging habitat selection of Wood Storks in the dry season.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/166457
Subject Headings: Water birds, Habitat, Florida, Habitat selection, Animal behavior, Wetland ecology
Format: Document (PDF)

Title: Subjecting the CHIMERA supernova code to two hydrodynamic test problems, (i) Riemann problem and (ii) Point blast explosion.
Creator: Ahsan, Abu Salah M., Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: A Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea...
Show moreA Shock wave as represented by the Riemann problem and a Point-blast explosion are two key phenomena involved in a supernova explosion. Any hydrocode used to simulate supernovae should be subjected to tests consisting of the Riemann problem and the Point-blast explosion. L. I. Sedov's solution of Point-blast explosion and Gary A. Sod's solution of a Riemann problem have been re-derived here from one dimensional fluid dynamics equations . Both these problems have been solved by using the idea of Self-similarity and Dimensional analysis. The main focus of my research was to subject the CHIMERA supernova code to these two hydrodynamic tests. Results of CHIMERA code for both the blast wave and Riemann problem have then been tested by comparing with the results of the analytic solution.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/172665
Subject Headings: Mathematical physics, Continuum mechanics, Number theory, Supernovae, Data processing, Shock waves, Fluid dynamics
Format: Document (PDF)

Title: Hierarchical resource selection and movement of two wading bird species with divergent foraging strategies in the Everglades.
Creator: Beerens, James M., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Seasonal variation in food availability is one of the primary limitations to avian populations, particularly during the breeding season. However, the behavioral responses between species may differ based on foraging strategies. I examined the influence of food availability on landscape-level habitat selection, patch-level habitat selection, and movements of two wading bird species with divergent foraging strategies, the Great Egret and White Ibis. On a landscape scale, there appeared to be a...
Show moreSeasonal variation in food availability is one of the primary limitations to avian populations, particularly during the breeding season. However, the behavioral responses between species may differ based on foraging strategies. I examined the influence of food availability on landscape-level habitat selection, patch-level habitat selection, and movements of two wading bird species with divergent foraging strategies, the Great Egret and White Ibis. On a landscape scale, there appeared to be a relationship among resource availability, the temporal scale of the independent variable, and whether the response was similar or different between species. At the patch level, results demonstrated a relationship between resource availability and the spatial scale of the independent variables selected by birds. Species movements were consistent with the differing strategies. This study is the first to make the link between landscape hydrology patterns, prey availability, and responses in wading bird habitat selection at multiple spatial scales.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/172667
Subject Headings: Water birds, Habitat, Habitat selection, Bird populations, Wetland ecology
Format: Document (PDF)

Title: Mapping urban growth in Boca Raton Florida, over a thirty year period.
Creator: Breary, Gillian., Charles E. Schmidt College of Science, Department of Geosciences
Abstract/Description: The rapid increase of urban growth is a major issue for many regions around the world, which result in astounding loss in farmlands and increase in population densities. It important that urban growth be monitored as it will aid the local government in implementing the appropriate measures for a growing population. The city of Boca Raton, Florida, is the case study for this research. A multi-temporal analysis is done of five Landsat satellite images over a thirty year time period, 1973-2002....
Show moreThe rapid increase of urban growth is a major issue for many regions around the world, which result in astounding loss in farmlands and increase in population densities. It important that urban growth be monitored as it will aid the local government in implementing the appropriate measures for a growing population. The city of Boca Raton, Florida, is the case study for this research. A multi-temporal analysis is done of five Landsat satellite images over a thirty year time period, 1973-2002. Textural analysis was performed on each of the images, to delineate the urban areas. Three by-products resulted from the textural analysis: time series tinted overlays, dasymetric mapping and a series of animated maps, showing the movement of growth across the landscape through time. All the resulting products of the time series analysis were used to show the magnitude and direction of growth over time.
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Date Issued: 2008
PURL: http://purl.flvc.org/fcla/dt/172668
Subject Headings: Urbanization, Cities and towns, Community development, Urban, Regional planning
Format: Document (PDF)

Title: The impacts of harmful algal blooms on a Florida reef fish community.
Creator: Baumberger, Rex E., Jr., Charles E. Schmidt College of Science, Biology
Abstract/Description: Coral reefs worldwide are threatened by many environmental disturbances including harmful algal blooms (HABs) which have been increasing on Florida coasts over the past decade. Research has mainly focused on HAB identification, percent cover and other effects on the benthos but the relationship of HABs with upper trophic levels has received less attention. To study this relationship, a two-year investigation on a 10-m deep reef off of Hallandale Beach, was conducted. Stationary fish census...
Show moreCoral reefs worldwide are threatened by many environmental disturbances including harmful algal blooms (HABs) which have been increasing on Florida coasts over the past decade. Research has mainly focused on HAB identification, percent cover and other effects on the benthos but the relationship of HABs with upper trophic levels has received less attention. To study this relationship, a two-year investigation on a 10-m deep reef off of Hallandale Beach, was conducted. Stationary fish census coupled with benthic transect videos were conducted quarterly between April 2005-July 2007. A significant correlation between Lyngbya sp. blooms and alterations in fish assemblages was observed. Lyngbya had a negative interaction with fish species and abundance; additionally, HAB sample periods were significantly different from low algal abundance periods. Blooms of Dictyota sp. had no measurable relationship with the fish assemblage indicating HABs may have variable impacts on fishes depending on family, species and chemistry of the algae.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186286
Subject Headings: Toxic algae, Environmental aspects, Algal blooms, Environmental aspects, Water quality biological assessment, Coral reef ecology
Format: Document (PDF)

Title: Roles of troponin I in heart development and cardiac function.
Creator: Du, Jianfeng., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Two major troponin I (TnI) genes, fetal TnI (ssTnI) and adult TnI (cTnI), are expressed in the mammalian heart under the control of a developmentally regulated program. In this study, the up-stream domain (~1,800 bp) of mouse fetal TnI gene has been cloned and characterized. There is a high homology of this region among mouse, rat and human. Transfection assays indicated that conserved GA-rich sequences, CREB and a CCAAT box within the first 300 bp upstream of the transcription start site...
Show moreTwo major troponin I (TnI) genes, fetal TnI (ssTnI) and adult TnI (cTnI), are expressed in the mammalian heart under the control of a developmentally regulated program. In this study, the up-stream domain (~1,800 bp) of mouse fetal TnI gene has been cloned and characterized. There is a high homology of this region among mouse, rat and human. Transfection assays indicated that conserved GA-rich sequences, CREB and a CCAAT box within the first 300 bp upstream of the transcription start site were critical for the gene expression. Electrophoretic mobility shift assays (EMSAs) and chromatin immunoprecipitation (ChIP) assays revealed binding proteins to CREB site in nuclear extracts from myocardial cells. Thyroid hormone (T3) caused a significant inhibitory effect on ssTnI expression in myocardial cells. Cardiac troponin I (cTnI) mutations have been linked to the development of restrictive cardiomyopathy (RCM) in human patients. We modeled one mutation in human cTnI Cv terminus, arginine1 92 histidine (R192H) by cardiac specific expression of the mutated protein (cTnI193His in mouse sequence) in transgenic mice. The main functional alteration detected in cTnI193His mice by ultrasound cardiac imaging examinations was impaired cardiac relaxation manifested by a decreased left ventricular end diastolic dimension (LVEDD) and an increased end diastolic dimension in both atria. Echocardiography revealed a series of changes on the transgenic mice including a reversed E-to-A ratio, increased deceleration time, and prolonged isovolumetric relaxation time. At the age of 12 months, cardiac output in cTnI193His mice was significantly declined, and some transgenic mice showed congestive heart failure. The negative impact of cTnI193His on ventricular contraction and relaxation was further demonstrated in isolated mouse working heart preparations., Dobutamine stimulation increased heart rate in cTnI193His mice but did not improve CO.The cTnI193His mice had a phenotype similar to that in human RCM patients carrying the cTnI mutation. The results demonstrate a critical role of the COOH-terminal domain of cTnI in the diastolic function of cardiac muscle. This mouse model provides us with a tool to further investigate the pathophysiology and the development of RCM.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186287
Subject Headings: Mice as laboratory animals, Biochemical markers, Diagnostic use, Heart, Diseases, Molecular diagnosis, Cardiovascular system, Pathophysiology
Format: Document (PDF)

Title: Mechanisms of protection against ischemic damage in the heart.
Creator: Moench, Ian, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Heart disease including ischemic heart disease is the highest contributor to death and morbidity in the western world. The studies presented were conducted to determine possible pathways of protection of the heart against ischemia/reperfusion. We employed adenovirus mediated over-expression of Methionine sulfoxide reductase A (MsrA) in primary neonatal rat cardiac myocytes to determine the effect of this enzyme in protecting against hypoxia/reoxygenation. Cells transfected with MsrA encoding...
Show moreHeart disease including ischemic heart disease is the highest contributor to death and morbidity in the western world. The studies presented were conducted to determine possible pathways of protection of the heart against ischemia/reperfusion. We employed adenovirus mediated over-expression of Methionine sulfoxide reductase A (MsrA) in primary neonatal rat cardiac myocytes to determine the effect of this enzyme in protecting against hypoxia/reoxygenation. Cells transfected with MsrA encoding adenovirus and subjected to hypoxia/reoxygenation exhibited a 45% decrease in apoptosis as compared to controls. Likewise total cell death as determined by levels of Lactate Dehydrogenase (LDH) release was dramatically decreased by MsrA overexpression. The initial hypothesis that led to our testing sulindac was based on the fact that the S epimer of sulindac was a substrate for MsrA and that this compound might function as a catalytic anti-oxidant based on a reaction cycle that involved reductio n to sulindac sulfide followed by oxidation back to sulindac. To test this we examined the protective effect of sulindac in hypoxia re-oxygenation in both cardiac myocytes in culture and using a Langendorff model of myocardial ischemia. Using this model of myocardial ischemia we showed that pre-incubation of hearts with sulindac, or the S and R epimers of sulindac resulted in protection against cell death. We present several lines of evidence that the protective effect of sulindac is not dependent on the Msr enzyme system nor does it involve the well established role of sulindac as a Cyclooxygenase (COX) inhibitor. Numerous signaling pathways have been implicated in myocardial protective mechanisms, many of which require fluctuations in ROS levels as initiators or mediators., Sulindac shows very good potential as a preconditioning agent that could induce tissue protection against oxidative damage.Blocking of preconditioning pathways by administration of the PKC blocker chelerythine abrogated the ischemic protection afforded by sulindac. Secondly, an end-effector of preconditioning, inducible nitric oxide synthase (iNOS),was found to be induced by greater than 5 fold after 48 h prior feeding sulindac.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186291
Subject Headings: Biochemical markers, Diagnostic use, Cardiovascular system, Diseases, Diagnosis, Heart, Diseases, Molecular aspects, Medical care, Quality control, Coronary heart disease, Prevention, Apoptosis, Myocardial infarction, Prevention
Format: Document (PDF)

Title: Computing topological dynamics from time series.
Creator: Wess, Mark., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: The topological entropy of a continuous map quantifies the amount of chaos observed in the map. In this dissertation we present computational methods which enable us to compute topological entropy for given time series data generated from a continuous map with a transitive attractor. A triangulation is constructed in order to approximate the attractor and to construct a multivalued map that approximates the dynamics of the linear interpolant on the triangulation. The methods utilize...
Show moreThe topological entropy of a continuous map quantifies the amount of chaos observed in the map. In this dissertation we present computational methods which enable us to compute topological entropy for given time series data generated from a continuous map with a transitive attractor. A triangulation is constructed in order to approximate the attractor and to construct a multivalued map that approximates the dynamics of the linear interpolant on the triangulation. The methods utilize simplicial homology and in particular the Lefschetz Fixed Point Theorem to establish the existence of periodic orbits for the linear interpolant. A semiconjugacy is formed with a subshift of nite type for which the entropy can be calculated and provides a lower bound for the entropy of the linear interpolant. The dissertation concludes with a discussion of possible applications of this analysis to experimental time series.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186294
Subject Headings: Algebraic topology, Graph theory, Fixed point theory, Singularities (Mathematics)
Format: Document (PDF)

Title: Engineered and natural TIMP mutations.
Creator: Hamze, Asmaa Bilal., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Tissue inhibitors of metalloproteinases (TIMPs) comprise a family of four proteins in humans that modulate the turnover of the extracellular matrix by regulating the activities of endopeptidases that catalyze its degradation, especially the matrix metalloproteinases (MMP). In general, the four TIMPs are broad-spectrum tight binding inhibitors of MMPs with individual differences in specificity. In this study, we attempted to understand the basis of such variation by using membrane type-1 MMP ...
Show moreTissue inhibitors of metalloproteinases (TIMPs) comprise a family of four proteins in humans that modulate the turnover of the extracellular matrix by regulating the activities of endopeptidases that catalyze its degradation, especially the matrix metalloproteinases (MMP). In general, the four TIMPs are broad-spectrum tight binding inhibitors of MMPs with individual differences in specificity. In this study, we attempted to understand the basis of such variation by using membrane type-1 MMP (MT1-MMP) as a model, since it is inefficiently inhibited by TIMP-1 in contrast with the other TIMPs. We designed and engineered mutations in the N-domain of TIMP-1, based on current knowledge of TIMP interactions. By measuring inhibition levels of each mutant against several MMPs, including MT1-MMP, we were able to obtain a triple mutant with an vii improved affinity for MT1-MMP., Our results, along with previous data, confirm that multiple residues in the critical interface segments between TIMPs and MMPs, namely at positions 2, 4, 5, 6, and 98, are key in determining the basic interaction between the two molecules. The second part of this work focused on naturally occurring mutations in TIMP-3 which cause an early form of macular degeneration called Sorsby's Fundus Dystrophy (SFD). The TIMP-3 mutants identified so far share certain features but the mechanism by which they result in macular disease is not yet understood. As an initial step, we expressed recombinant TIMP-3 carrying a truncation mutation, glutamic acid 139 to a stop codon (E139X), and assessed its activity towards representative MMPs and tumor necrosis factor-(Sa (Bconverting enzyme, another metalloproteinase normally inhibited by TIMP-3. Our results indicate that this mutation does not impair the inhibitory activity of TIMP-3., Expression of this mutant in mammalian retinal cells revealed a difference in localization between wild-type and E139X mutant TIMP-3. Therefore, we concluded that the SFD mutations may actually influence the processing and/or binding properties of TIMP-3 in the retina.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186296
Subject Headings: Proteolytic enzymes, Extracellular matrix proteins, Metalloproteinases, Inhibitors, Apoptosis, Retinal degeneration, Research
Format: Document (PDF)

Title: System justification requires psychological proximity.
Creator: Martens, Nicholas J., Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: System justification theorists have proposed that people will defend one's circumstances, even if they inflict psychological and material costs. This tendency has been found to extend even to outcomes that have not yet been decided, but are perceived as being likely; however, this research has only examined outcomes that will be decided on in the near future. According to Construal Level Theory (CLT), distant future events are represented primarily according to their essential features, while...
Show moreSystem justification theorists have proposed that people will defend one's circumstances, even if they inflict psychological and material costs. This tendency has been found to extend even to outcomes that have not yet been decided, but are perceived as being likely; however, this research has only examined outcomes that will be decided on in the near future. According to Construal Level Theory (CLT), distant future events are represented primarily according to their essential features, while thoughts about temporally near events are more concrete and contextual. We hypothesized that system justification results from the motivational impact of low-level thinking, and so would be expected to occur for near-future, but not distant-future, outcomes. Consistent with our hypothesis, our Main Study found evidence of system justification only when outcomes were to be decided in the near future. Distant future outcomes, in contrast, were viewed as being more undesirable as they became increasingly likely.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186299
Subject Headings: Motivation (Psychology), Social service, Psychological aspects, Resilience (Personality trait), Affect (Psychology), Study and teaching
Format: Document (PDF)

Title: A role for polynucleotide phosphorylase in protecting cells and controlling RNA quality under oxidative stress.
Creator: Wu, Jinhua., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: RNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG...
Show moreRNA damage occurring under oxidative stress has been shown to cause RNA dysfunction and must be detrimental to cells and organisms. We propose that damaged RNA can be removed by specific RNA surveillance activities. In this work, we investigated the role of polynucleotide phosphorylase (PNPase), a 3'->5' exoribonuclease, in protecting the cells against oxidative stress and eliminating oxidatively-damaged RNA. Previously, it was reported that E. coli PNPase has a higher affinity to poly(8-oxoG:A). We further confirmed that E. coli PNPase can specifically bind to an oxidized RNA with a high affinity. An E. coli strain deficient in PNPase (pnp) is hypersensitive to hydrogen peroxide (H2O2). Importantly, the level of H2O2-induced RNA damage, measured by the content of 8-hydroxyguanosine, increases significantly in the pnp mutant cells. Consistent with the notion that PNPase plays a direct role in these processes, introduction of the pnp gene encoding E. coli PNPase can restore the viability and RNA oxidation level of the pnp mutant cells in response to H2O2 treatment. Interestingly, degradosome-association is not required for PNPase to protect cell against oxidative stress. PNPase is evolutionary conserved in most of organisms of all domains of life. The human polynucleotide phosphorylase (hPNPase) localizes mainly in mitochondria and plays pleiotropic roles in cell differentiation and has been previously shown to bind 8- oxoG-RNA with a high affinity. Here we show that similar to E. coli PNPase, hPNPase plays an indispensable role in protecting HeLa cells against oxidative stress. The viability in HeLa cell and 8-oxoG levels in RNA are inversely correlated in response to H2O2- treatment. After removal of oxidative challenge, the elevated level of 8-oxoG in RNA decreases, suggesting the existence of surveillance mechanism(s) for cleaning up oxidized RNA., We have shown that hPNPase may be responsible for the surveillance of oxidized RNA in mammalian cells.Overexpresion of hPNPase reduces RNA oxidation and increases HeLa cell viability against H2O2 insult. Conversely, hPNPase knockdown decreases the viability and increases 8-oxoG level in HeLa cells exposed to H2O2. Taken together, our results suggest that RNA oxidation is a challenging problem for living organisms, and PNPase may play an important role in protecting both prokaryotic and eukaryotic cells by limiting damage to RNA under oxidative stress.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/186302
Subject Headings: RNA, Metabolism, Biopolymers, Physiological transport, Bacterial genetics, Proteins, Synthesis, Cellular signal transduction
Format: Document (PDF)

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