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Title: An evaluation of methodology, dispersal and habitat usage of largemouth bass (Micropterus salmoides floridanus) from a supplemental stocking on Lake Okeechobee, Florida.
Creator: Jordan, Alyssa., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The largemouth bass (Micropterus salmoides) fishery was at an all time low on Lake Okeechobee when experimental supplemental stockings were done to try and enhance local bass populations. Largemouth bass had never been stocked on a large lake like Lake Okeechobee. The objectives were to develop a methodology, study dispersal, and compare stocked versus wild bass habitat choices. The methodology underwent considerable changes between studies. Bass dispersed to the edges by the second sampling...
Show moreThe largemouth bass (Micropterus salmoides) fishery was at an all time low on Lake Okeechobee when experimental supplemental stockings were done to try and enhance local bass populations. Largemouth bass had never been stocked on a large lake like Lake Okeechobee. The objectives were to develop a methodology, study dispersal, and compare stocked versus wild bass habitat choices. The methodology underwent considerable changes between studies. Bass dispersed to the edges by the second sampling period, so a larger sampling area may be needed. Water depth and pH were found to be significantly different between wild and stocked bass. Hatchery bass are naèive about predators, which may have resulted in stocked bass not moving to shallower areas like wild bass. The pH was weakly correlated with depth, so differences may be partially due to the fact that as depth increases, pH may also increase.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3342199
Subject Headings: Largemouth bass, Habitat, Largemouth bass, Ecology, Freshwater ecology, Fishery management, Ecology
Format: Document (PDF)

Title: The enumeration of lattice paths and walks.
Creator: Gao, Shanzhen., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: A well-known long standing problem in combinatorics and statistical mechanics is to find the generating function for self-avoiding walks (SAW) on a two-dimensional lattice, enumerated by perimeter. A SAW is a sequence of moves on a square lattice which does not visit the same point more than once. It has been considered by more than one hundred researchers in the pass one hundred years, including George Polya, Tony Guttmann, Laszlo Lovasz, Donald Knuth, Richard Stanley, Doron Zeilberger,...
Show moreA well-known long standing problem in combinatorics and statistical mechanics is to find the generating function for self-avoiding walks (SAW) on a two-dimensional lattice, enumerated by perimeter. A SAW is a sequence of moves on a square lattice which does not visit the same point more than once. It has been considered by more than one hundred researchers in the pass one hundred years, including George Polya, Tony Guttmann, Laszlo Lovasz, Donald Knuth, Richard Stanley, Doron Zeilberger, Mireille Bousquet-Mlou, Thomas Prellberg, Neal Madras, Gordon Slade, Agnes Dit- tel, E.J. Janse van Rensburg, Harry Kesten, Stuart G. Whittington, Lincoln Chayes, Iwan Jensen, Arthur T. Benjamin, and many others. More than three hundred papers and a few volumes of books were published in this area. A SAW is interesting for simulations because its properties cannot be calculated analytically. Calculating the number of self-avoiding walks is a common computational problem. A recently proposed model called prudent self-avoiding walks (PSAW) was first introduced to the mathematics community in an unpublished manuscript of Pra, who called them exterior walks. A prudent walk is a connected path on square lattice such that, at each step, the extension of that step along its current trajectory will never intersect any previously occupied vertex. A lattice path composed of connected horizontal and vertical line segments, each passing between adjacent lattice points. We will discuss some enumerative problems in self-avoiding walks, lattice paths and walks with several step vectors. Many open problems are posted.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3183129
Subject Headings: Combinatorial analysis, Approximation theory, Mathematical statistics, Limit theorems (Probabilty theory)
Format: Document (PDF)

Title: The effects of water depth and vegetation on wading bird foraging habitat selection and foraging succes in the Everglades.
Creator: Lantz, Samantha., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Successful foraging by avian predators is influenced largely by prey availability. In a large-scale experiment at the Loxahatchee Impoundment Landscape Assessment project within the Arthur R. Marshall Loxahatchee National Wildlife Refuge, I manipulated two components of prey availability, water depth and vegetation density (submerged aquatic vegetation and emergent vegetation), and quantified the response by wading birds in terms of foraging habitat selection and foraging success. Manly's...
Show moreSuccessful foraging by avian predators is influenced largely by prey availability. In a large-scale experiment at the Loxahatchee Impoundment Landscape Assessment project within the Arthur R. Marshall Loxahatchee National Wildlife Refuge, I manipulated two components of prey availability, water depth and vegetation density (submerged aquatic vegetation and emergent vegetation), and quantified the response by wading birds in terms of foraging habitat selection and foraging success. Manly's standardized selection index showed that birds preferred shallow water and intermediate vegetation densities. However, the treatments had little effect on either individual capture rate or efficiency. This was a consistent pattern seen across multiple experiments. Birds selected for certain habitat features but accrued little benefit in terms of foraging success. I hypothesize that birds selected sites with shallow water and intermediate vegetation densities because they anticipated higher prey densities, but they did not experience it here because I controlled for prey density.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/2788592
Subject Headings: Water birds, Habitat, Wetland ecology, Habitat selection, Avian ecology, Wildlife management
Format: Document (PDF)

Title: The discrete logarithm problem in non-abelian groups.
Creator: Iliâc, Ivana., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: This dissertation contains results of the candidate's research on the generalized discrete logarithm problem (GDLP) and its applications to cryptology, in non-abelian groups. The projective special linear groups PSL(2; p), where p is a prime, represented by matrices over the eld of order p, are investigated as potential candidates for implementation of the GDLP. Our results show that the GDLP with respect to specic pairs of PSL(2; p) generators is weak. In such cases the groups PSL(2; p) are...
Show moreThis dissertation contains results of the candidate's research on the generalized discrete logarithm problem (GDLP) and its applications to cryptology, in non-abelian groups. The projective special linear groups PSL(2; p), where p is a prime, represented by matrices over the eld of order p, are investigated as potential candidates for implementation of the GDLP. Our results show that the GDLP with respect to specic pairs of PSL(2; p) generators is weak. In such cases the groups PSL(2; p) are not good candidates for cryptographic applications which rely on the hardness of the GDLP. Results are presented on generalizing existing cryptographic primitives and protocols based on the hardness of the GDLP in non-abelian groups. A special instance of a cryptographic primitive dened over the groups SL(2; 2n), the Tillich-Zemor hash function, has been cryptanalyzed. In particular, an algorithm for constructing collisions of short length for any input parameter is presented. A series of mathematical results are developed to support the algorithm and to prove existence of short collisions.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/3356783
Subject Headings: Data encryption (Computer science), Computer security, Cryptography, Combinatorial group theory, Data processing, Mapping (Mathematics)
Format: Document (PDF)

Title: A comparison of stability in swimming loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle posthatchlings.
Creator: Dougherty, Erin., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Posthatchling green (Chelonia mydas) and loggerhead (Caretta caretta) turtles overlap ecologically but differ morphologically. This study compared hydrodynamic stability between the two species during swimming to test for functional differences in body shape. Flipper movement paths, four stability measures (yaw, pitch, heave, and sideslip), and the relative positions of the centers of buoyancy and gravity were compared between species. Both centers of buoyancy and gravity lie in the anterior...
Show morePosthatchling green (Chelonia mydas) and loggerhead (Caretta caretta) turtles overlap ecologically but differ morphologically. This study compared hydrodynamic stability between the two species during swimming to test for functional differences in body shape. Flipper movement paths, four stability measures (yaw, pitch, heave, and sideslip), and the relative positions of the centers of buoyancy and gravity were compared between species. Both centers of buoyancy and gravity lie in the anterior body; their positions relative to one another differed with species, but showed no functional consequences. Neither species demonstrated substantial yaw, sideslip, or pitch. Both experienced upward heave with the flippers' downstroke and downward heave with the upstroke; however phase relationships differed between these limb and body motions. No differences were found between the two species. Despite obvious morphological differences, loggerheads and green turtles were similarly stable during swimming, suggesting that the species use different mechanisms to achieve stability.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/186689
Subject Headings: Sea turtles, Morphology, Sea turtles, Physiology, Animal locomotion, Marine ecology
Format: Document (PDF)

Title: A test of factors affecting the foraging success of scarlet ibis.
Creator: Stanek, Rebecca A., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Wading bird foraging success is influenced by many different factors. From January to March 2008, I conducted a small-scale experiment with three captive Scarlet Ibis (Eudocimus ruber) at the Palm Beach Zoo, in West Palm Beach, Florida. Prey density and the presence of conspecifics were manipulated to test for a response by ibis in terms of prey capture rate. Mixed model analysis, when one prey type was available, showed that capture rate increased significantly with prey density and...
Show moreWading bird foraging success is influenced by many different factors. From January to March 2008, I conducted a small-scale experiment with three captive Scarlet Ibis (Eudocimus ruber) at the Palm Beach Zoo, in West Palm Beach, Florida. Prey density and the presence of conspecifics were manipulated to test for a response by ibis in terms of prey capture rate. Mixed model analysis, when one prey type was available, showed that capture rate increased significantly with prey density and decreased with the presence of conspecifics. When two prey types were available, prey density and the presence of conspecifics had no effect on the capture rates of either prey type. Selectivity analysis revealed that ibis always selected for crayfish in mixed treatments. I hypothesize that the number of prey types available in a treatment played an important role in determining how fish density and the presence of conspecifics affected ibis foraging success.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/215288
Subject Headings: Scarlet ibis, Food, Birds, Ecology, Birds, Behavior, Wildlife management, Predation (Biology)
Format: Document (PDF)

Title: On the minimal logarithmic signature conjecture.
Creator: Singhi, Nidhi., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: The minimal logarithmic signature conjecture states that in any finite simple group there are subsets Ai, 1 i s such that the size jAij of each Ai is a prime or 4 and each element of the group has a unique expression as a product Qs i=1 ai of elements ai 2 Ai. Logarithmic signatures have been used in the construction of several cryptographic primitives since the late 1970's [3, 15, 17, 19, 16]. The conjecture is shown to be true for various families of simple groups including cyclic groups,...
Show moreThe minimal logarithmic signature conjecture states that in any finite simple group there are subsets Ai, 1 i s such that the size jAij of each Ai is a prime or 4 and each element of the group has a unique expression as a product Qs i=1 ai of elements ai 2 Ai. Logarithmic signatures have been used in the construction of several cryptographic primitives since the late 1970's [3, 15, 17, 19, 16]. The conjecture is shown to be true for various families of simple groups including cyclic groups, An, PSLn(q) when gcd(n; q 1) is 1, 4 or a prime and several sporadic groups [10, 9, 12, 14, 18]. This dissertation is devoted to proving that the conjecture is true for a large class of simple groups of Lie type called classical groups. The methods developed use the structure of these groups as isometry groups of bilinear or quadratic forms. A large part of the construction is also based on the Bruhat and Levi decompositions of parabolic subgroups of these groups. In this dissertation the conjecture is shown to be true for the following families of simple groups: the projective special linear groups PSLn(q), the projective symplectic groups PSp2n(q) for all n and q a prime power, and the projective orthogonal groups of positive type + 2n(q) for all n and q an even prime power. During the process, the existence of minimal logarithmic signatures (MLS's) is also proven for the linear groups: GLn(q), PGLn(q), SLn(q), the symplectic groups: Sp2n(q) for all n and q a prime power, and for the orthogonal groups of plus type O+ 2n(q) for all n and q an even prime power. The constructions in most of these cases provide cyclic MLS's. Using the relationship between nite groups of Lie type and groups with a split BN-pair, it is also shown that every nite group of Lie type can be expressed as a disjoint union of sets, each of which has an MLS.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3172946
Subject Headings: Finite groups, Abelian groups, Number theory, Combinatorial group theory, Mathematical recreations, Linear algebraic groups, Lie groups
Format: Document (PDF)

Title: Investigating maternal health and hatchling mortality in leatherback sea turtles (Dermochelys coriacea v.).
Creator: Perrault, Justin R., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The reproductive success of leatherback turtles (Dermochelys coriacea) is typically the lowest of the seven sea turtle species. Why this vital rate is decreased has remained unanswered for nearly a century. Recently, detailed postmortem examination of leatherback hatchlings identified muscular pathologies that suggested possible selenium deficiency. High bodily burdens of mercury compounds are associated with selenium depletion. Selenium is a necessary detoxifying nutrient that itself can be...
Show moreThe reproductive success of leatherback turtles (Dermochelys coriacea) is typically the lowest of the seven sea turtle species. Why this vital rate is decreased has remained unanswered for nearly a century. Recently, detailed postmortem examination of leatherback hatchlings identified muscular pathologies that suggested possible selenium deficiency. High bodily burdens of mercury compounds are associated with selenium depletion. Selenium is a necessary detoxifying nutrient that itself can be toxic at elevated concentrations. Mercury compounds are toxicants with no known biological function. High bodily concentrations of mercury can be detrimental to marine organismal health, reproduction and survival, both directly and indirectly through inducing selenium depletion. The goals of this dissertation are to evaluate several related hypotheses to explain low leatherback nest success. ... Because leatherbacks take in high volumes of prey, high tissue concentrations of mercury and selenium can result. This study provides the first evidence that chemical contaminants may explain low reproductive success in leatherback sea turtles.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362575
Subject Headings: Selenium, Physiological effect, Predation (Biology), Leatherback turtle, Mortality, Sea turtles, Mortality, Wildlife conservation
Format: Document (PDF)

Title: Intra and interspecies association patterns of Atlantic spotted dolphins, Stenella frontalis, and Atlantic bottlenose dolphins, Tursiops truncatus, and the effects of demographic changes following two major hurricanes.
Creator: Elliser, Cindy Rogers., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Demographic changes, through immigration/emigration (or death) can affect the social and community structure of a population. This study reports on the effects of demographic changes following 2 intense hurricanes on two sympatric delphinid species: Atlantic bottlenose dolphins, Tursiops truncatus, and Atlantic spotted dolphins Stenella frontalis. Thirty percent of the bottlenose population was lost after the hurricanes, with an influx of roughly the same number of immigrants. The stable...
Show moreDemographic changes, through immigration/emigration (or death) can affect the social and community structure of a population. This study reports on the effects of demographic changes following 2 intense hurricanes on two sympatric delphinid species: Atlantic bottlenose dolphins, Tursiops truncatus, and Atlantic spotted dolphins Stenella frontalis. Thirty percent of the bottlenose population was lost after the hurricanes, with an influx of roughly the same number of immigrants. The stable community split into two cohesive units. Preferences in association in relation to reproductive status and sex remained. Immigrants assimilated well into the population, especially males. There is a conflict of interest between resident males and females in accepting immigrants and often females find more resistance than males. Long-term analysis of spotted dolphins revealed a community structure defined by long-term site fidelity, natal philopatry of both sexes and three social clusters., Female associations were influenced by reproductive status and social familiarity within clusters. Males formed long-term alliances and shorter-term coalitions. Some movement between clusters occurred. Alliance formation crystallized in adulthood. Mating strategies and sex were the primary factors shaping social structure. Thirty-six percent of the spotted dolphin population was lost after the hurricanes with no influx of immigrants. The spotted dolphin community differed little from long-term analysis, including definitive social clusters and sex preferences. Social cohesion increased within units and across age classes. Some juveniles had associations of alliance level. Loss of individuals resulted in subtle changes in social structure. Interspecies associations reveal striking differences in association patterns between species. Group sizes and re-sightings of spotted dolphins were larger than for bottlenose dolphins, particularly for aggressive encounters., Male alliances and coalitions were prevalent for spotted dolphins, but not for bottlenose dolphins. After the hurricanes lower re-sighting and group sizes for spotted dolphin males and less aggressive behavior documented, indicates a re-structuring period of relationships between the species. This study shows that environmental variations may alter the structure of mammal societies through demographic upheaval and survival of populations may depend on their social structure and the social adaptability of the species.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1927313
Subject Headings: Social behavior in animals, Dolphins, Geographical distribution, Population genetics, Weather, Environmental aspects
Format: Document (PDF)

Title: Signature schemes in single and multi-user settings.
Creator: Villanyi, Viktoria., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: In the first chapters we will give a short introduction to signature schemes in single and multi-user settings. We give the definition of a signature scheme and explain a group of possible attacks on them. In Chapter 6 we give a construction which derives a subliminal-free RSA public key. In the construction we use a computationally binding and unconditionally hiding commitment scheme. To establish a subliminal-free RSA modulus n, we have to construct the secret primes p and q. To prove p and...
Show moreIn the first chapters we will give a short introduction to signature schemes in single and multi-user settings. We give the definition of a signature scheme and explain a group of possible attacks on them. In Chapter 6 we give a construction which derives a subliminal-free RSA public key. In the construction we use a computationally binding and unconditionally hiding commitment scheme. To establish a subliminal-free RSA modulus n, we have to construct the secret primes p and q. To prove p and q are primes we use Lehmann's primality test on the commitments. The chapter is based on the paper, "RSA signature schemes with subliminal-free public key" (Tatra Mountains Mathematical Publications 41 (2008)). In chapter 7 a one-time signature scheme using run-length encoding is presented, which in the random oracle model offers security against chosen-message attacks. For parameters of interest, the proposed scheme enables about 33% faster verification with a comparable signature size than a construction of Merkle and Winternitz. The public key size remains unchanged (1 hash value). The main cost for the faster verification is an increase in the time required for signing messages and for key generation. The chapter is based on the paper "A one-time signature using run-length encoding" (Information Processing Letters Vol. 108, Issue 4, (2008)).
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/215289
Subject Headings: Information technology, Security measures, Cryptography, Coding theory, Data encryption (Computer science), DIgital watermarking
Format: Document (PDF)

Title: Shamir's secret sharing scheme using floating point arithmetic.
Creator: Finamore, Timothy., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: Implementing Shamir's secret sharing scheme using floating point arithmetic would provide a faster and more efficient secret sharing scheme due to the speed in which GPUs perform floating point arithmetic. However, with the loss of a finite field, properties of a perfect secret sharing scheme are not immediately attainable. The goal is to analyze the plausibility of Shamir's secret sharing scheme using floating point arithmetic achieving the properties of a perfect secret sharing scheme and...
Show moreImplementing Shamir's secret sharing scheme using floating point arithmetic would provide a faster and more efficient secret sharing scheme due to the speed in which GPUs perform floating point arithmetic. However, with the loss of a finite field, properties of a perfect secret sharing scheme are not immediately attainable. The goal is to analyze the plausibility of Shamir's secret sharing scheme using floating point arithmetic achieving the properties of a perfect secret sharing scheme and propose improvements to attain these properties. Experiments indicate that property 2 of a perfect secret sharing scheme, "Any k-1 or fewer participants obtain no information regarding the shared secret", is compromised when Shamir's secret sharing scheme is implemented with floating point arithmetic. These experimental results also provide information regarding possible solutions and adjustments. One of which being, selecting randomly generated points from a smaller interval in one of the proposed schemes of this thesis. Further experimental results indicate improvement using the scheme outlined. Possible attacks are run to test the desirable properties of the different schemes and reinforce the improvements observed in prior experiments.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3342048
Subject Headings: Signal processing, Digital techniques, Mathematics, Data encryption (Computer science), Computer file sharing, Security measures, Computer algorithms, Numerical analysis, Data processing
Format: Document (PDF)

Title: Stochastic optimal impulse control of jump diffusions with application to exchange rate.
Creator: Perera, Sandun C., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: We generalize the theory of stochastic impulse control of jump diffusions introduced by Oksendal and Sulem (2004) with milder assumptions. In particular, we assume that the original process is affected by the interventions. We also generalize the optimal central bank intervention problem including market reaction introduced by Moreno (2007), allowing the exchange rate dynamic to follow a jump diffusion process. We furthermore generalize the approximation theory of stochastic impulse control...
Show moreWe generalize the theory of stochastic impulse control of jump diffusions introduced by Oksendal and Sulem (2004) with milder assumptions. In particular, we assume that the original process is affected by the interventions. We also generalize the optimal central bank intervention problem including market reaction introduced by Moreno (2007), allowing the exchange rate dynamic to follow a jump diffusion process. We furthermore generalize the approximation theory of stochastic impulse control problems by a sequence of iterated optimal stopping problems which is also introduced in Oksendal and Sulem (2004). We develop new results which allow us to reduce a given impulse control problem to a sequence of iterated optimal stopping problems even though the original process is affected by interventions.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/3174308
Subject Headings: Management, Mathematical models, Control theory, Stochastic differential equations, Distribution (Probability theory), Optimal stopping (Mathematical statistics), Economics, Mathematical
Format: Document (PDF)

Title: Stability analysis for nonlinear systems with time-delays.
Creator: Tiwari, Shanaz, Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: In this work, we investigate input-to-state stability (ISS) and other related stability properties for control systems with time-delays. To overcome the complexity caused by the presence of the delays, we adopt a Razumikhin approach. The underlying idea of this approach is to treat the delayed variables as system uncertainties. The advantage of this approach is that one works in the more familiar territory of stability analysis for delay-free systems in the context of ISS instead of carrying...
Show moreIn this work, we investigate input-to-state stability (ISS) and other related stability properties for control systems with time-delays. To overcome the complexity caused by the presence of the delays, we adopt a Razumikhin approach. The underlying idea of this approach is to treat the delayed variables as system uncertainties. The advantage of this approach is that one works in the more familiar territory of stability analysis for delay-free systems in the context of ISS instead of carrying out stability analysis on systems of functional differential equations. Our first step is to provide criteria on ISS and input-to-input stability properties based on the Razumikhin approach. We then turn our attention to large-scale interconnected systems. It has been well recognized that the small-gain theory is a powerful tool for stability analysis of interconnected systems. Using the Razumikhin approach, we develop small-gain theorems for interconnected systems consisting of two or more subs ystems with time-delays present either in the interconnection channels or within the subsystems themselves. As an interesting application, we apply our results to an existing model for hematopoesis, a blood cell production process,and improve the previous results derived by linear methods. Another important stability notion in the framework of ISS is the integral ISS (iISS) property. This is a weaker property than ISS, so it supplies to a larger class of systems. As in the case of ISS, we provide Razumikhin criteria on iISS for systems with delays. An example is presented to illustrate that though very useful in practice, the Razumikhin approach only provides sufficient conditions, not equivalent conditions. Finally, we address stability of time-varying systems with delays in the framework of ISS., In particular, we consider Lyapunov-Razumikhin functions whose decay rates are affected by time-varying functions that can be zero or even negative on some sets of non-zero measure. Our motivation is that it is often less demanding to find or construct such a Lyapunov function than one with a uniform decay rate. We also extend our small-gain theorems to the time-varying case by treating the time-varying system as an auxiliary time-invariant system.
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Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352880
Subject Headings: Nonlinear systems, Simulation methods, Control theory, Stability, Mathematical models, Mathematical optimization
Format: Document (PDF)

Title: Studies on the role of vitamin D in asthma patients from a South Florida pulmonary practice.
Creator: Munim, Amjad., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Vitamin D insufficiency/deficiency is widespread in asthma, and epidemiological studies point to an association between low serum 25-hydroxyvitamin D level and poor asthma control and increased severity. In humans. Vitamin D is principally derived from sunlight induced cutaneous conversion of 7-dehydrocholesterol to vitamin D and oral supplementation. We sought to determine if established and chronic-persistent adult asthma patients from a South-Florida pulmonary patient population, with...
Show moreVitamin D insufficiency/deficiency is widespread in asthma, and epidemiological studies point to an association between low serum 25-hydroxyvitamin D level and poor asthma control and increased severity. In humans. Vitamin D is principally derived from sunlight induced cutaneous conversion of 7-dehydrocholesterol to vitamin D and oral supplementation. We sought to determine if established and chronic-persistent adult asthma patients from a South-Florida pulmonary patient population, with abundant sunshine availability and oral vitamin D supplementation exhibit vitamin D insufficiency/deficiency. A trend to vitamin D insufficiency was observed in approximately 65% of both adult asthma patients and apparently healthy (non-asthmatic) volunteers. . The transcription factors required for Th9 conversion, PU.1 and IRF-4, were down-regulated by vitamin D. The generation of Th9 cells was inhibited equally by vitamin D and dexamethasone when used alone, but the effect was additive when both steroids were used in combination. Our studies using non-specifically stimulated cells were extended by analyzing the effect of vitamin D on allergen specific stimulation. The response of CD4+ T cells obtained from the blood of house dust mite positive asthmatics was studied. House dust mite allergen elicited a classical Th2 phenotype response (IL-4, IL-5, IL-9, and IL-13 cytokine profile) and vitamin D effectively inhibited those key Th2 cytokines. We conclude that vitamin D appears to be of significant clinical benefit in our cohort of patients, i.e., established chronic adult human asthma, by down-regulating key immune cells including Th9, Th17, and Th2 involved in this disorder.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3360948
Subject Headings: Vitamin D, Health aspects, Vitamin D, Physiological effect, Vitamin D, Therapeutic use, Vitamin D, Physiology, Vitamin D in human nutrition, Lungs, Etiology
Format: Document (PDF)

Title: Sun compass orientation in juvenile green sea turtles (Chelonia mydas).
Creator: Mott, Cody Robert., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Recent studies show that sea turtles use both magnetic and visual cues to successfully orient. Juvenile green sea turtles from the near shore reefs of Palm Beach County, Florida were brought to the lab to determine whether the sun could serve as a visual orientation cue. When tethered during the day in a large outdoor tank west of the ocean, the turtles oriented east to northeast. To determine whether the sun's position was used to maintain their heading, I altered the turtles' perception of...
Show moreRecent studies show that sea turtles use both magnetic and visual cues to successfully orient. Juvenile green sea turtles from the near shore reefs of Palm Beach County, Florida were brought to the lab to determine whether the sun could serve as a visual orientation cue. When tethered during the day in a large outdoor tank west of the ocean, the turtles oriented east to northeast. To determine whether the sun's position was used to maintain their heading, I altered the turtles' perception of time by entraining them to a light cycle advanced by 7 h relative to the natural cycle. When tested afterward in the same outdoor tank the turtles oriented northwest, the predicted direction after compensating for the sun's movement over 7 h across the sky. Orientation was unchanged when the turtles bore magnets that negated the use of magnetic cues. These results are consistent with the hypothesis that the turtles used the sun for orientation.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2705073
Subject Headings: Animal orientation, Adaptation (Biology), Animal navigation, Sea turtles, Migration
Format: Document (PDF)

Title: Studies of specific gene expression of phosphate transporters in sawgrass (Cladium jamaicense crantz) and cattail (Typha domingensis pers.).
Creator: Lin, Li, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: In the Florida Everglades, sawgrass has been displaced by cattail, predominantly resulting from phosphate enrichment. It has been found that phosphate transporters and arbuscular mycorrhizal (AM) fungi play an important role in phosphate uptake in the plants. This study aimed to reveal the symbiosis between AM fungi and sawgrass and cattail and identify the phosphate transporters, especially AM-specific phosphate transporters in these two species. AM colonization was only found in sawgrass...
Show moreIn the Florida Everglades, sawgrass has been displaced by cattail, predominantly resulting from phosphate enrichment. It has been found that phosphate transporters and arbuscular mycorrhizal (AM) fungi play an important role in phosphate uptake in the plants. This study aimed to reveal the symbiosis between AM fungi and sawgrass and cattail and identify the phosphate transporters, especially AM-specific phosphate transporters in these two species. AM colonization was only found in sawgrass roots, not cattail, at low phosphate concentrations in lab and field samples by trypan blue staining. AM fungi could increase sawgrass growth and had little effect on cattail growth. Four phosphate transporters were identified in sawgrass. CjPT1, CjPT2 and CjPT3 were expressed in roots and shoots independent of AM fungi and phosphate availability, while CjPT4 appeared to be an AM regulated phosphate transporter gene and its expression was induced by AM fungi.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1930493
Subject Headings: Phosphorus, Physiological transport, Soil stabilization, Vegetation dynamics, Ecosystem management, Soil mineralogy, Plant physiology
Format: Document (PDF)

Title: Studies on the mechanism by which sulindac sensitizes cancer cells to oxidative stress.
Creator: Kreymerman, Alexander, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Sulindac is a known NSAID that has also been shown to have anti-cancer activity that is not related to its ability to inhibit COX 1 and 2. During the past 15 years there have been a large number of studies attempting to elucidate its mechanism of action. Our laboratory has shown that sulindac can both protect normal cells and enhance the killing of cancer cells under oxidative stress from H2O2 and TBHP. However, except for mitochondrial dysfunction and ROS production, the mechanism by which...
Show moreSulindac is a known NSAID that has also been shown to have anti-cancer activity that is not related to its ability to inhibit COX 1 and 2. During the past 15 years there have been a large number of studies attempting to elucidate its mechanism of action. Our laboratory has shown that sulindac can both protect normal cells and enhance the killing of cancer cells under oxidative stress from H2O2 and TBHP. However, except for mitochondrial dysfunction and ROS production, the mechanism by which sulindac sensitized the cancer cells to oxidative stress remains unknown. Results of this research project suggest that the effect of sulindac and oxidative stress not only involves mitochondrial ROS production, but also aspects of the preconditioning response. In normal cells this leads to survival by a preconditioning pathway, likely involving PKCε. . However, cancer cells react by initiating a pathway leading to apoptosis involving PKCδ.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3183124
Subject Headings: Proteins, Chemical modification, Cellular signal transduction, Biochemical markers, Diagnostic use, Drug resistance in cancer cells, Oxidation-reduction reaction
Format: Document (PDF)

Title: Regional differences in migratory activity by hatchling loggerhead sea turtles (Caretta caretta): effect of reciprocal nest translocations.
Creator: Guertin, Jeffrey, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: There are four distinct subpopulations of loggerhead sea turtles (Caretta caretta) in Florida as determined behaviorally by geographic fidelity, and genetically by mitochondrial haplotypes. The South Florida subpopulation consists of females nesting on the southeastern and southwestern coasts of Florida and their offspring. Previous research shows that west coast hatchlings exhibit higher levels of nocturnal swimming during the postfrenzy period than east coast hatchlings. This study...
Show moreThere are four distinct subpopulations of loggerhead sea turtles (Caretta caretta) in Florida as determined behaviorally by geographic fidelity, and genetically by mitochondrial haplotypes. The South Florida subpopulation consists of females nesting on the southeastern and southwestern coasts of Florida and their offspring. Previous research shows that west coast hatchlings exhibit higher levels of nocturnal swimming during the postfrenzy period than east coast hatchlings. This study attempted to determine how these differences in migratory behavior develop. A reciprocal translocation experiment was conducted to distinguish between environmental and genetic factors. No consistent differences in hatchling swimming behavior were seen based on geography. Movement of nests resulted in lower levels of nocturnal swimming behavior in hatchlings compared to hatchlings that emerged from natural nests, suggesting that the relocation of nests may not provide a natural incubation environment for developing hatchlings.
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Date Issued: 2010
PURL: http://purl.flvc.org/FAU/1927867
Subject Headings: Predation (Biology), Sea turtles, Migration, Animal migration, Animal orientation
Format: Document (PDF)

Title: Polynomials that are integer valued on the image of an integer-valued polynomial.
Creator: Marshall, Mario V., Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description: Let D be an integral domain and f a polynomial that is integer-valued on D. We prove that Int(f(D);D) has the Skolem Property and give a description of its spectrum. For certain discrete valuation domains we give a basis for the ring of integer-valued even polynomials. For these discrete valuation domains, we also give a series expansion of continuous integer-valued functions.
Date Issued: 2009
PURL: http://purl.flvc.org/FAU/216411
Subject Headings: Polynomials, Ring of integers, Ideals (Algebra)
Format: Document (PDF)

Title: Regulation of rapid signaling at the cone ribbon synapse via distinct pre- and postsynaptic mechanisms.
Creator: Rowan, Matthew JM., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Background: Light-adaptation is a multifaceted process in the retina that helps adjust the visual system to changing illumination levels. Many studies are focused on the photochemical mechanism of light-adaptation. Neural network adaptation mechanisms at the photoreceptor synapse are largely unknown. We find that large, spontaneous Excitatory Amino Acid Transporter (EAATs) activity in cone terminals may contribute to cone synaptic adaptation, specifically with respect to how these signals...
Show moreBackground: Light-adaptation is a multifaceted process in the retina that helps adjust the visual system to changing illumination levels. Many studies are focused on the photochemical mechanism of light-adaptation. Neural network adaptation mechanisms at the photoreceptor synapse are largely unknown. We find that large, spontaneous Excitatory Amino Acid Transporter (EAATs) activity in cone terminals may contribute to cone synaptic adaptation, specifically with respect to how these signals change in differing conditions of light. EAATs in neurons quickly transport glutamate from the synaptic cleft, and also elicit large thermodynamically uncoupled Cl- currents when activated. We recorded synaptic EAAT currents from cones to study glutamate-uptake events elicited by glutamate release from the local cone, and from adjacent photoreceptors. We find that cones are synaptically connected via EAATs in dark ; this synaptic connection is diminished in light-adapted cones. Methods: Whole-cell patch-clamp was performed on dark- and transiently light-adapted tiger salamander cones. Endogenous EAAT currents were recorded in cones with a short depolarization to -10mV/2ms, while spontaneous transporter currents from network cones were observed while a local cone holding at -70mV constantly. DHKA, a specific transporter inhibitor, was used to identify EAAT2 currents in the cone terminals, while TBOA identified other EAAT subtypes. GABAergic and glycinergic network inputs were always blocked with picrotoxin and strychnine. Results: Spontaneous EAAT currents were observed in cones held constantly at -70mV in dark, indicating that the cones received glutamate inputs from adjacent photoreceptors. These spontaneous EAAT currents disappeared in presence of a strong light, possibly because the light suppressed glutamate releases from the adjacent photoreceptors. The spontaneous EAAT currents were blocked with TBOA, but not DHKA, an inhibitor for EAAT2 subtype, suggesting that a, non-EAAT 2 subtype may reside in a basal or perisynaptic area of cones, with a specialized ability to bind exocytosed glutamate from adjacent cones in dark. Furthermore, these results could be artificially replicated by dual-electrode recordings from two adjacent cones. When glutamate release was elicited from one cone, the TBOA-sensitive EAAT currents were observed from the other cone. Conclusions: Cones appear to act like a meshwork, synaptically connected via glutamate transporters. Light attenuates glutamate release and diminishes the cone-cone synaptic connections. This process may act as an important network mechanism for cone light adaptation.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3337186
Subject Headings: Synapses, Neural transmission, VIsual perception, Presynaptic receptors, Molecular neurobiology, Glutamic acid, Neural receptors, Cellular signal transduction, Retina, Cytology
Format: Document (PDF)

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