Current Search: info:fedora/islandora:entityCModel (x) » FAU (x) » Charles E. Schmidt College of Science (x)
View All Items
Pages
- Title
- Ocean Acidification Effects on Photosynthesis in Tropical Marine Macroalgae.
- Creator
- Zweng, Regina C., Koch, Marguerite, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Field data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms,...
Show moreField data from CO2 vents, a current model of future ocean acidification conditions, show a positive correlation between elevated seawater pCO2 and fleshy macroalgal abundance, as well as a negative correlation between elevated seawater pCO2 and calcareous macroalgal abundance on coral reefs. One underlying physiological mechanism for increases of fleshy macroalgae species in response to greater pCO2 could be an increase in their photosynthesis. Furthermore, inorganic carbon use mechanisms, irradiance and depth may influence species-specific responses to ocean acidification. Therefore, this thesis aimed to discern carbon use strategies and photosynthetic responses to elevated pCO2 of dominant tropical fleshy and calcareous macroalgae. All species studied were able to utilize HCO3 - for photosynthesis. 33% of calcifying macroalgae and 80% of fleshy macroalgae had increased photosynthetic rates in response to lower pH. Thus, future conditions of OA may perpetuate or exacerbate the abundance of fleshy seaweeds at the expense of calcareous species.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004879, http://purl.flvc.org/fau/fd/FA00004879
- Subject Headings
- Marine algae--Ecophysiology., Algal communities--Monitoriing., Coral reef ecology.
- Format
- Document (PDF)
- Title
- Deep-Water Biogenic Sediment off the Coast of Florida.
- Creator
- Zuccarelli, Claudio L., Oleinik, Anton E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Biogenic “oozes” are pelagic sediments that are composed of > 30% carbonate microfossils and are estimated to cover about 50% of the ocean floor, which accounts for about 67% of calcium carbonate in oceanic surface sediments worldwide. These deposits exhibit diverse assemblages of planktonic microfossils and contribute significantly to the overall sediment supply and function of Florida’s deep-water regions. However, the composition and distribution of biogenic sediment deposits along these...
Show moreBiogenic “oozes” are pelagic sediments that are composed of > 30% carbonate microfossils and are estimated to cover about 50% of the ocean floor, which accounts for about 67% of calcium carbonate in oceanic surface sediments worldwide. These deposits exhibit diverse assemblages of planktonic microfossils and contribute significantly to the overall sediment supply and function of Florida’s deep-water regions. However, the composition and distribution of biogenic sediment deposits along these regions remains poorly documented. Seafloor surface sediments have been collected in situ via Johnson- Sea-Link I submersible along four of Florida’s deep-water regions during a joint research cruise between Harbor Branch Oceanographic Institute (HBOI) and Florida Atlantic University (FAU). Sedimentological analyses of the taxonomy, species diversity, and sedimentation dynamics reveal a complex interconnected development system of Florida’s deep-water habitats. Results disclose characteristic microfossil assemblages of planktonic foraminiferal ooze off the South West Florida Shelf, a foraminiferal-pteropod ooze through the Straits of Florida, and pteropod ooze deposits off Florida’s east coast. The distribution of the biogenic ooze deposits is attributed to factors such as oceanographic surface production, surface and bottom currents, off-bank transport, and deep-water sediment drifts. The application of micropaleontology, sedimentology, and oceanography facilitate in characterizing the sediment supply to Florida’s deep-water regions.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004857
- Subject Headings
- Marine sediments., Sediment transport., Deep-sea ecology., Ecosystem management., Micropaleontology
- Format
- Document (PDF)
- Title
- Synthesis of Complex Polycyclic Scaffolds Incorporating α-Amino Esters.
- Creator
- Zorc, Stephen A., Samanta, Shyam S., Roche, Stéphane P., Charles E. Schmidt College of Science
- Abstract/Description
-
In order to keep up with the high demand for biologically active molecules, chemists devised several synthetic strategies to access novel chemical spaces. The two main strategies to construct new scaffolds are to revisit underexploited or forgotten reactions or to devise new transformations. We are exploring a unique and underexploited reaction, the Himbert–Henn cycloaddition, to produce complex molecular scaffolds in a single step (strategy 1). In a second novel approach, we are modifying...
Show moreIn order to keep up with the high demand for biologically active molecules, chemists devised several synthetic strategies to access novel chemical spaces. The two main strategies to construct new scaffolds are to revisit underexploited or forgotten reactions or to devise new transformations. We are exploring a unique and underexploited reaction, the Himbert–Henn cycloaddition, to produce complex molecular scaffolds in a single step (strategy 1). In a second novel approach, we are modifying the Hantzsch 4-component reaction (4CR) by incorporating an α-amino ester residue to construct new molecules (strategy 2). Both of these reactions have great potential to synthesize novel and chiral molecules from proteinogenic α-amino esters. These unprecedented and complex polycyclic molecules have potential application in medicinal chemistry and natural product synthesis. 4-aza-podophyllotoxins obtained by the Hantzsch-4CR have been proven to be potent as anti-leukemia, anti-colon cancer, and vascular disrupting agents (with nanomolar activity).
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00005218
- Subject Headings
- College students --Research --United States.
- Format
- Document (PDF)
- Title
- High Resolution Population Distribution Estimates for Improved Decision Making, With a Case Study of Sea-Level Rise Vulnerability in Boca Raton, Florida.
- Creator
- Ziegler, Hannes Moritz, Xie, Zhixiao, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Planners and managers often rely on coarse population distribution data from the census for addressing various social, economic, and environmental problems. In the analysis of physical vulnerabilities to sea-level rise, census units such as blocks or block groups are coarse relative to the required decision-making application. This study explores the benefits offered from integrating image classification and dasymetric mapping at the household level to provide detailed small area population...
Show morePlanners and managers often rely on coarse population distribution data from the census for addressing various social, economic, and environmental problems. In the analysis of physical vulnerabilities to sea-level rise, census units such as blocks or block groups are coarse relative to the required decision-making application. This study explores the benefits offered from integrating image classification and dasymetric mapping at the household level to provide detailed small area population estimates at the scale of residential buildings. In a case study of Boca Raton, FL, a sea-level rise inundation grid based on mapping methods by NOAA is overlaid on the highly detailed population distribution data to identify vulnerable residences and estimate population displacement. The enhanced spatial detail offered through this method has the potential to better guide targeted strategies for future development, mitigation, and adaptation efforts.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004670
- Subject Headings
- City planning -- Remote sensing, Community development, Urban -- Florida -- Boca Raton, Geographic information systems, Population -- Geographic information systems -- Florida -- Boca Raton, egional planning -- Florida -- Boca Raton, Spatial analysis (Statistics), Urban geography -- Remote sensing
- Format
- Document (PDF)
- Title
- INTRASEXUAL SELECTION AND THE ELABORATION OF A MATING SIGNAL IN THE BACHMAN’S SPARROW (PEUCEA AESTIVALIS).
- Creator
- Ziadi, Paula, Anderson, Rindy, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Vocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the...
Show moreVocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the evolution of large and complex song repertoires remains an evolutionary puzzle (Byers and Kroodsma 2009). The question is: why do some songbird species produce an elaborate vocal repertoire, while other species carry out courtship and competition with a far smaller and simpler repertoire? In this thesis I examine the adaptive value (social function) of song in malemale competition with an eye toward understanding how intrasexual selection may have driven the elaboration of the male Bachman’s sparrow (Peucea aestivalis) vocal repertoire.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013352
- Subject Headings
- Bachman's sparrow, Songbirds--Behavior, Songbirds--Vocalization, Birds--Sexual behavior
- Format
- Document (PDF)
- Title
- Decay for time-dependent Schroedinger equations.
- Creator
- Zhou, Zhen, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
- Abstract/Description
-
We study the decay in time of solutions of Schrodinger equations of the type du/du=idelta u+iV(t)u, establishing that for small potentials and initial data in L1 the solution u satisfies sup[u(x,t)](x element of R)
Show moreWe study the decay in time of solutions of Schrodinger equations of the type du/du=idelta u+iV(t)u, establishing that for small potentials and initial data in L1 the solution u satisfies sup[u(x,t)](x element of R)Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12463
- Subject Headings
- Mathematics
- Format
- Document (PDF)
- Title
- Synthesis and In Vitro Evaluation of Some Novel Nucleoside analogs and DNA lntercalators as Potential Anticancer or Antiviral Agents.
- Creator
- Zhao, Yuxiang, Florida Atlantic University, Parkanyi, Cyril, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Thiadiazoles can be considered as analogs of pyrimidines because of the well known analogy between a -CH=CH- group in benzenoid hydrocarbons and bivalent sulfur, -S-, in aromatic heterocycles. Therefore, 5-amino-2H-1 ,2,4-thiadiazole-3-one and 5-amino-3H-1 ,3,4-thiadiazole-2-one are the analogs of cytosine. In our first project, the preparation of six thiadiazole nucleoside analogs is reported: 5-diacetylamino-1 ,2,4- thiadiazol-3-one (1), 5-amino-2-(tetrahydrofuran-2-yl)-1 ,2,4-thiadiazol-3...
Show moreThiadiazoles can be considered as analogs of pyrimidines because of the well known analogy between a -CH=CH- group in benzenoid hydrocarbons and bivalent sulfur, -S-, in aromatic heterocycles. Therefore, 5-amino-2H-1 ,2,4-thiadiazole-3-one and 5-amino-3H-1 ,3,4-thiadiazole-2-one are the analogs of cytosine. In our first project, the preparation of six thiadiazole nucleoside analogs is reported: 5-diacetylamino-1 ,2,4- thiadiazol-3-one (1), 5-amino-2-(tetrahydrofuran-2-yl)-1 ,2,4-thiadiazol-3-one (2), 5- amino-3-((2' -hydroxyethoxy)methyl)-1 ,3,4-thiadiazol-2-one (3), 5-amino-3-( 4' -hydroxy- 2' -hydroxyrnethyl-butyl)-1 ,3,4-thiadiazole-2-thione ( 4), (R)-5-am ino-3-(2' ,3' - dihydroxypropyl)-1 ,3,4-thiadiazole-2-thione (5), and (S)-5-amino-3-(2' ,3 ' - dihydroxypropyl )-1 ,3,4-thiadiazole-2-thione (6). (R)-5-amino-3-(2' ,3' -dihydroxypropyl)-1,3,4-thiadiazole-2-thione (5) and (S)-5-amino-3-(2' ,3' -dihydroxypropyl)-1 ,3,4- thiadiazole-2-thione (6) are stereoisomers. Their racemic mixture 7 was also prepared and tested. The synthesis, characterization, and properties of these new synthesized thiadiazole derivatives are discussed. A dimerization of 5-amino-3H-1 ,3 ,4-thiadiazole-2- thione (18) to produce di-(5-amino-1 ,3,4-thiadiazol-2-yl) disulfide (23) by sodium nitrite with either acetic acid or stannic chloride is also reported. Preliminary results indicate that 3 and 23 possess antimicrobial activity. In the second project, the synthesis of three series of bis-aminochloropyrimidine derivatives with different types of linkers as potential DNA intercalators is described. The first series are aminochloropyrimidines bridged by polyrnethylene chain linkers with various lengths. The second series are bridged by polyether linkers to lower the lipophilicity. The third series are bridged by linkers containing benzene rings to limit the flexibility. The spectral data and other physical properties of the new compounds are discussed. The preliminary screening results indicate that many new synthesized bisintercalators are biologically active. The relationship between bioactivity and structure is discussed as well.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000886
- Subject Headings
- Biopharmaceutics, Antineoplastic agents--Pharmacodynamics, Nucleosides--Metabolism, Pharmaceutical chemistry, Antiviral agents--Synthesis
- Format
- Document (PDF)
- Title
- Detection of multiple change-points in hazard models.
- Creator
- Zhang, Wei, Qian, Lianfen, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
- Abstract/Description
-
Change-point detection in hazard rate function is an important research topic in survival analysis. In this dissertation, we firstly review existing methods for single change-point detection in piecewise exponential hazard model. Then we consider the problem of estimating the change point in the presence of right censoring and long-term survivors while using Kaplan-Meier estimator for the susceptible proportion. The maximum likelihood estimators are shown to be consistent. Taking one step...
Show moreChange-point detection in hazard rate function is an important research topic in survival analysis. In this dissertation, we firstly review existing methods for single change-point detection in piecewise exponential hazard model. Then we consider the problem of estimating the change point in the presence of right censoring and long-term survivors while using Kaplan-Meier estimator for the susceptible proportion. The maximum likelihood estimators are shown to be consistent. Taking one step further, we propose an counting process based and least squares based change-point detection algorithm. For single change-point case, consistency results are obtained. We then consider the detection of multiple change-points in the presence of long-term survivors via maximum likelihood based and counting process based method. Last but not least, we use a weighted least squares based and counting process based method for detection of multiple change-points with long-term survivors and covariates. For multiple change-points detection, simulation studies show good performances of our estimators under various parameters settings for both methods. All methods are applied to real data analyses.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004173
- Subject Headings
- Problem solving--Data processing., Process control--Statistical methods., Point processes., Mathematical statistics., Failure time data analysis--Data processing., Survival analysis (Biometry)--Data processing.
- Format
- Document (PDF)
- Title
- Detecting essential genes in microarray dataset with unequal number of gene probes.
- Creator
- Zhang, Wei, Qian, Lianfen, Charles E. Schmidt College of Science, Department of Mathematical Sciences
- Abstract/Description
-
Microarray technology is a powerful approach for genomic research, which allows the monitoring of expressing profiles for tens of thousands genes in parallel and is already producing huge amounts of data. This thesis is motivated by a special microarray dataset for the bacteria Yersinia Pestis. It contains more than four thousands genes and each gene has different number of observations. The main purpose of this thesis is to detect essentially functional genes. Gene level adjusted multiple t...
Show moreMicroarray technology is a powerful approach for genomic research, which allows the monitoring of expressing profiles for tens of thousands genes in parallel and is already producing huge amounts of data. This thesis is motivated by a special microarray dataset for the bacteria Yersinia Pestis. It contains more than four thousands genes and each gene has different number of observations. The main purpose of this thesis is to detect essentially functional genes. Gene level adjusted multiple t‐test is proposed to handle the problem of unequal number of observations. Furthermore, a comparation study of our method with two other existing methods (Behrens‐Fisher method and Hotelling t‐square method) are presented. The comparison results show that our proposed methods is the best for identifying essential genes.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/fau/fd/FA00004261
- Format
- Document (PDF)
- Title
- The Coordination Dynamics of Multiple Agents.
- Creator
- Zhang, Mengsen, Tognoli, Emmanuelle, Kelso, J. A. Scott, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
A fundamental question in Complexity Science is how numerous dynamic processes coordinate with each other on multiple levels of description to form a complex whole - a multiscale coordinative structure (e.g. a community of interacting people, organs, cells, molecules etc.). This dissertation includes a series of empirical, theoretical and methodological studies of rhythmic coordination between multiple agents to uncover dynamic principles underlying multiscale coordinative structures. First,...
Show moreA fundamental question in Complexity Science is how numerous dynamic processes coordinate with each other on multiple levels of description to form a complex whole - a multiscale coordinative structure (e.g. a community of interacting people, organs, cells, molecules etc.). This dissertation includes a series of empirical, theoretical and methodological studies of rhythmic coordination between multiple agents to uncover dynamic principles underlying multiscale coordinative structures. First, a new experimental paradigm was developed for studying coordination at multiple levels of description in intermediate-sized (N = 8) ensembles of humans. Based on this paradigm, coordination dynamics in 15 ensembles was examined experimentally, where the diversity of subjects movement frequency was manipulated to induce di erent grouping behavior. Phase coordination between subjects was found to be metastable with inphase and antiphase tendencies. Higher frequency diversity led to segregation between frequency groups, reduced intragroup coordination, and dispersion of dyadic phase relations (i.e. relations at di erent levels of description). Subsequently, a model was developed, successfully capturing these observations. The model reconciles the Kuramoto and the extended Haken-Kelso-Bunz model (for large- and small-scale coordination respectively) by adding the second-order coupling from the latter to the former. The second order coupling is indispensable in capturing experimental observations and connects behavioral complexity (i.e. multistability) of coordinative structures across scales. Both the experimental and theoretical studies revealed multiagent metastable coordination as a powerful mechanism for generating complex spatiotemporal patterns. Coexistence of multiple phase relations gives rise to many topologically distinct metastable patterns with di erent degrees of complexity. Finally, a new data-analytic tool was developed to quantify complex metastable patterns based on their topological features. The recurrence of topological features revealed important structures and transitions in high-dimensional dynamic patterns that eluded its non-topological counterparts. Taken together, the work has paved the way for a deeper understanding of multiscale coordinative structures.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013111
- Subject Headings
- Complexity science, Coordination dynamics, Nonlinear Dynamics, Nonlinear systems and complexity
- Format
- Document (PDF)
- Title
- Isolation and Structural Elucidation of Novel Bioactive Natural Products from Marine Organisms of the Western Atlantic Ocean.
- Creator
- Zhang, Long, West, Lyndon, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The aim of this dissertation was to elaborate the exploration of biologically active secondary metabolites from the marine sponge Cacospongia cf. linteiformis collected from the Bahamas and the soft coral Briareum asbestinum collected from two different sites in Florida State, Boca Raton and Dry Tortugas. In chapter one, a review on previous chemical and biological studies of the marine sponge C. cf. linteiformis and soft coral B. asbestinum is provided. Particular attention is given to...
Show moreThe aim of this dissertation was to elaborate the exploration of biologically active secondary metabolites from the marine sponge Cacospongia cf. linteiformis collected from the Bahamas and the soft coral Briareum asbestinum collected from two different sites in Florida State, Boca Raton and Dry Tortugas. In chapter one, a review on previous chemical and biological studies of the marine sponge C. cf. linteiformis and soft coral B. asbestinum is provided. Particular attention is given to spongianolides and briarellins, two important classes of compounds isolated from C. cf. linteiformis and B. asbestinum, respectively, and their structural features and diverse bioactivities. In chapter two, the isolation and relative configuration determination of four epimeric sesterterpenoids, spongianolides E & F (18c, 18d, 19c, 19d) from C. cf. linteiformis collected from the Bahamas are discussed. Thanks to chemical modification (acetylation), diastereomeric 18c&18d and 19c&19d, respectively, were able to be isolated using chromatographic techniques for the first time, and then the relative configurations of 18c, 18d, 19c, 19d were determined based on NOESY NMR experiments. The bioactivity of mixture of compounds 18c, 18d, 19c, 19d were tested and it exhibited inhibition against Schnurri-3 (a regulator of postnatal bone mass). In chapter three, the isolation and structural elucidation of four new compounds, florellins A-D (49-52), from B. asbestinum collected off the coast of Boca Raton, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Compounds 49-52 are the first briarellins containing an acyl group at C-13, while 49 and 50 are the first briarellins possessing acylation at C-15. Florellins A–C (49-51) were screened and found cytotoxic against three human cell lines, BT474, WM266−4 and HEK293. In chapter four, the isolation and structural elucidation of four new compounds, florellins E-H (57-60), from B. asbestinum collected in Dry Tortugas, FL are discussed. The molecular structures of these compounds were established by spectroscopic analysis. Florellins F (58) and H (60) were screened against three human cell lines, BT474, WM266−4 and HEK293, but no cytotoxicity was exhibited. In chapter five, all the experimental procedures are described, including analytical instruments, animal materials, extraction and isolation processes, spectroscopic data and protocols of bioassays.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004850, http://purl.flvc.org/fau/fd/FA00004850
- Subject Headings
- Pharmacognosy., Natural products--Analysis., Marine pharmacology., Marine biotechnology., Marine algae--Biotechnology., Bioactive compounds.
- Format
- Document (PDF)
- Title
- A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING.
- Creator
- Zhang, Ke, Christie, Jason, Dawson-Scully, Ken, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Performance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to...
Show morePerformance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to alter behavior. Molecular layer interneurons (MLIs) inhibit Purkinje cells to modulate dendritic excitability and action potential output. How MLIs contribute to the regulation and encoding of climbing fiber-evoked adaptive movements remains poorly understood. In this dissertation, I used genetic tools to manipulate the activity of MLIs while monitoring Purkinje cell dendritic activity during a cerebellum-dependent motor learning task with different contexts to evaluate how MLIs are involved in this process. The results show that by suppressing dendritic Ca2+ signals in Purkinje cells, MLI activity coincident with climbing fiber-mediated excitation prevents the occurrence of learning when adaptation is not necessary. On the other hand, with error signals present, disinhibition onto Purkinje cells, mediated by MLI-MLI microcircuit, unlocked the ability of climbing fibers to induce plasticity and motor learning.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013526
- Subject Headings
- Cerebellum, Interneurons, Purkinje cells, Dendrites, Sensorimotor integration, Neuroplasticity
- Format
- Document (PDF)
- Title
- OPTIMAL PORTFOLIO FOR THE INFORMED INVESTOR IN MISPRICED LEVY MARKET WITH STOCHASTIC VOLATILITY AND POWER UTILITY.
- Creator
- Zephirin, Duval, Long, Hongwei, Florida Atlantic University, Department of Mathematical Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
We consider a portfolio optimization problem in stochastic volatility jump-diffusion model. The model is a mispriced Lévy market that contains informed and uninformed investors. Contrarily to the uninformed investor, the informed investor knows that a mispricing exists in the market. The stock price follows a jump-diffusion process, the mispricing and volatility are modelled by Ornstein-Uhlenbeck (O-U) process and Cox-Ingersoll-Ross (CIR) process, respectively. We only present results for the...
Show moreWe consider a portfolio optimization problem in stochastic volatility jump-diffusion model. The model is a mispriced Lévy market that contains informed and uninformed investors. Contrarily to the uninformed investor, the informed investor knows that a mispricing exists in the market. The stock price follows a jump-diffusion process, the mispricing and volatility are modelled by Ornstein-Uhlenbeck (O-U) process and Cox-Ingersoll-Ross (CIR) process, respectively. We only present results for the informed investor whose goal is to maximize utility from terminal wealth over a finite investment horizon under the power utility function. We employ methods of stochastic calculus namely Hamilton-Jacobi-Bellman equation, instantaneous centralized moments of returns and three-level Crank-Nicolson method. We solve numerically the partial differential equation associated with the optimal portfolio. Under the power utility function, analogous results to those obtain in the jump-diffusion model under logarithmic utility function and deterministic volatility are obtained.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00014040
- Subject Headings
- Investments, Portfolio, Lévy processes, Utility functions
- Format
- Document (PDF)
- Title
- Passive acoustics as a monitoring tool for evaluating oyster reef restoration.
- Creator
- Zenil Becerra, Hilde P., Charles E. Schmidt College of Science, Center for Environmental Studies
- Abstract/Description
-
Oyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and...
Show moreOyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and restored oyster reefs, with special attention on snapping shrimp (Alpheus spp.) snap sounds, in the St. Lucie Estuary, Florida over a one year period. Season, estuary region, habitat and day period had an effect on sound production. Passive acoustic monitoring of snapping shrimp sound production may be a useful non-destructive technique for monitoring the progress of oyster reef restoration projects once further correlations are established between environmental effects and sound production.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3352882
- Subject Headings
- American oyster, Ecosystem management, Restoration ecology, Aquatic ecology, Underwater acoustics
- Format
- Document (PDF)
- Title
- Neural Correlates of Auditory Perception, Attention and Expectation.
- Creator
- Zanto, Theodore P., Florida Atlantic University, Large, Edward W., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
This dissertation examined the neural correlates of auditory perception, attention and expectation in three experiments. Experiment 1 analyzed neural correlates of auditory perception and expectation in an electroencephalography (EEG) experiment using a temporally perturbed metronome to establish an expectation for auditory events, then violate and reestablish that expectation. High frequency evoked (phase-locked) gamma band activity (GBA) was observed to follow the onset of tones whereas...
Show moreThis dissertation examined the neural correlates of auditory perception, attention and expectation in three experiments. Experiment 1 analyzed neural correlates of auditory perception and expectation in an electroencephalography (EEG) experiment using a temporally perturbed metronome to establish an expectation for auditory events, then violate and reestablish that expectation. High frequency evoked (phase-locked) gamma band activity (GBA) was observed to follow the onset of tones whereas induced (nonphase- locked) GBA reached maximum power simultaneously with the occurrence oftone onset. Moreover, the latency of induced GBA was perturbed after an expectancy violation and relaxed back into synchrony as the expectation was reestablished. Experiment 2 was a methodological study to compare two functional magnetic resonance imaging (fMRJ) scanning techniques and assess their influence on auditory processing. Subjects passively listened to isochronous tone sequences at three rates while sparse or continuous scanning was employed. Sparse and continuous scanning was observed to yield comparable fMRI data, however, continuous scanner notse was observed to perturb known EEG evoked response potentials. Moreover, high frequency evoked activity, as identified by spectral analysis, was attenuated in the presence of continuous fMRl noise. Experiment 3 was conducted to study auditory expectancy and attention. First, subjects were tested behaviorally to determine their ability to tap the beat of ten highly syncopated patterns. Subjects were asked to return for one EEG and one fMRl session. In these sessions, they were instructed to attend to a syncopated pattern, mentally rehearse the pattern, and then reproduce the pattern. During the control condition, subjects heard the auditory patterns, however, they were instructed to study a list of words, remember the words during the retention interval, and then recall as many words as possible. Brain activity was localized to frontal and auditory regions when attending to the patterns and occipital-auditory areas when attending to the words. Evoked activity was shown to reflect the subject's anticipation of the beat and was attenuated when ignoring the auditory stimulus. Taken together, these results suggest that GBA indexes auditory perception, attention and expectation. The current results suggest that attention and task engagement may elicit stronger neural phase locking.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fau/fd/FA00000885
- Subject Headings
- Electrophysiology, Auditory evoked response, Electroencephalography, Auditory perception, Intersensory effects, Auditory pathways
- Format
- Document (PDF)
- Title
- Photodegradation of 2-mercaptobenzothiazole disulfide and related benzothiazoles.
- Creator
- Zajickova, Zuzana, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Benzothiazoles are heterocyclic compounds used predominantly as rubber vulcanization accelerators. The overall goal of our research was to investigate the photodegradation behavior of 2-mercaptobenzothiazole disulfide, its degradation product 2-mercaptobenzothiazole, and further degradation product benzothiazole. Modern analytical techniques were utilized to follow photodegradation process at arbitrary intervals. A chromatographic method using reverse phase liquid chromatography was developed...
Show moreBenzothiazoles are heterocyclic compounds used predominantly as rubber vulcanization accelerators. The overall goal of our research was to investigate the photodegradation behavior of 2-mercaptobenzothiazole disulfide, its degradation product 2-mercaptobenzothiazole, and further degradation product benzothiazole. Modern analytical techniques were utilized to follow photodegradation process at arbitrary intervals. A chromatographic method using reverse phase liquid chromatography was developed for the separation of benzothiazoles in the irradiated mixture. Direct photolysis of benzothiazole and 2-mercaptobenzothiazole in methanol at 253.7 and 313 nm in the presence or absence of oxygen was investigated at first. Benzothiazole was found to undergo photodimerization into 2,2'-bibenzothiazole, and in the presence of oxygen to give two additional photoproducts - 2-hydroxybenzothiazole and 2-methylbenzothiazole. The major degradation products of 2-mercaptobenzothiazole are benzothiazole and 2-benzothiazolesulfonic acid, with 2,2'-thiobisbenzothiazole, 2,x'-thiobisbenzothiazole (x = 4, 5, 6, 7), and 2-mercaptobenzothiazole disulfide as the minor degradation products. Direct photolysis of 2-mercaptobenzothiazole disulfide was investigated in four different solvents, at two different wavelengths (253.7 and 313 nm) and concentrations in the presence or absence of oxygen. In all cases 2-mercaptobenzothiazole and 2,x'-thiobisbenzothiazole were detected as the degradation products and in acetonitrile 2-thiocyanatobenzothiazole was also detected. A mechanism is proposed to rationalize the formation of photodegradation products. The effects of solvent, irradiation wavelength, and duration of irradiation time, concentration of the starting material and presence or absence of oxygen are summarized as well. It was observed that photodecomposition at 253.7 nm occurred at a much faster rate than at 313 nm and that less concentrated solutions decomposed faster. At higher concentration of 2-mercaptobenzothiazole its disulfide was detected as one of the degradation products. Methylated products were detected in methanol and acetonitrile and photoreaction took longer in polar protic solvents. Oxygenated products were formed in presence of oxygen and the photoreaction was slower as well in comparison to degassed solutions.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/12219
- Subject Headings
- Chemistry, Analytical, Chemistry, Physical
- Format
- Document (PDF)
- Title
- Attitudes and perspectives about backyard food gardening: a case study in South Florida.
- Creator
- Zahina-Ramos, John G., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
As cities grew throughout the past century, the availability of locally grown food declined, mostly because urban expansion occurred at the expense of adjacent agricultural land. As a result, city dwellers turned to commercial food market systems that import food from distant production areas. Private greenspace, which is one of the largest land cover types in cities, offers the potential for substantial agricultural production. Because urban food production on private land, such as backyards...
Show moreAs cities grew throughout the past century, the availability of locally grown food declined, mostly because urban expansion occurred at the expense of adjacent agricultural land. As a result, city dwellers turned to commercial food market systems that import food from distant production areas. Private greenspace, which is one of the largest land cover types in cities, offers the potential for substantial agricultural production. Because urban food production on private land, such as backyards, requires the willing participation of landowners, resident's feelings about and experience with food growing are important to understand. The demographic groups that were most likely to food garden were those in long-term relationships, higher income brackets, those with college education and residents over 50 years old. Incentives and programs focused on producing more from existing gardens may be most appropriate for people in these demographic groups, while other groups will most require basic food growing information. Study participants highly valued intangible benefits of food gardening (e.g., relaxation, feelings of happiness and satisfaction), often more than the provision of food. Most barriers and problems with backyard food growing, such as a lack of space and the need for gardening information, were similar for those who food garden and those who do not. Results from this study indicate that traditional agricultural incentives and perspectives must be rethought if they are to be applied in urban settings. By creating incentives and initiatives that reflect the needs and challenges faced by urban growers, urban agriculture will become an integrated part of the community, improving food quantity and quality while enriching residents' lives.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3361258
- Subject Headings
- Backyard gardens, Food chains (Ecology), Garden ecology, Green movement, Sustainable development
- Format
- Document (PDF)
- Title
- Genetic and Neural Mechanisms Regulating the Interaction Between Sleep and Metabolism in Drosophila Melanogaster.
- Creator
- Yurgel, Maria E., Keene, Alex C., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Dysregulation of sleep and metabolism has enormous health consequences. Sleep loss is linked to increased appetite and insulin insensitivity, and epidemiological studies link chronic sleep deprivation to obesity-related disorders. Interactions between sleep and metabolism involve the integration of signalling from brain regions regulating sleep, feeding, and metabolism, as well as communication between the brain and peripheral organs. In this series of studies, using the fruit fly as a model...
Show moreDysregulation of sleep and metabolism has enormous health consequences. Sleep loss is linked to increased appetite and insulin insensitivity, and epidemiological studies link chronic sleep deprivation to obesity-related disorders. Interactions between sleep and metabolism involve the integration of signalling from brain regions regulating sleep, feeding, and metabolism, as well as communication between the brain and peripheral organs. In this series of studies, using the fruit fly as a model organism, we investigated how feeding information is processed to regulate sleep, and how peripheral tissues regulate sleep through the modulation of energy stores. In order to address these questions, we performed a large RNAi screen to identify novel genetic regulators of sleep and metabolism. We found that, the mRNA/DNA binding protein, Translin (trsn), is necessary for the acute modulation of sleep in accordance with feeding state. Flies mutant for trsn or selective knockdown of trsn in Leucokinin (Lk) neurons abolishes starvation-induced sleep suppression. In addition, genetic silencing of Lk neurons or a mutation in the Lk locus also disrupts the integration between sleep and metabolism, suggesting that Lk neurons are active during starvation. We confirmed this hypothesis by measuring baseline activity during fed and starved states. We found that LHLK neurons, which have axonal projections to sleep and metabolic centers of the brain, are more active during starvation. These findings suggest that LHLK neurons are modulated in accordance with feeding state to regulate sleep. Finally, to address how peripheral tissues regulate sleep, we performed an RNAi screen, selectively knocking down genes in the fat body. We found that knockdown of Phosphoribosylformylglycinamidine synthase (Ade2), a highly conserved gene involved the biosynthesis of purines, regulates sleep and energy stores. Flies heterozygous for two Ade2 mutations are short sleepers and this effect is partially rescued by restoring Ade2 to the fly fat body. These findings suggest Ade2 functions within the fat body to promote both sleep and energy storage, providing a functional link between these processes. Together, the experimental evidence presented here provides an initial model for how the peripheral tissues communicate to the brain to modulate sleep in accordance with metabolic state.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013163
- Subject Headings
- Drosophila melanogaster, Sleep, Metabolism
- Format
- Document (PDF)
- Title
- Role of Attachment Orientation in the Perception of Support Provision.
- Creator
- Yurchyshyn, Liliya, Maniaci, Michael, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
- Abstract/Description
-
We examined how adult attachment styles influence human perception of support provision. We invited 119 couples to the lab, where they performed an exploration task. We also used pre- and post-exploration measures, including assessing adult attachment styles and partners' perception of support provided during the task. Three independent coders watched the videos of couples interacting and rated partners' support provision behavior. We utilized West and Kenny's (2011) truth and bias model to...
Show moreWe examined how adult attachment styles influence human perception of support provision. We invited 119 couples to the lab, where they performed an exploration task. We also used pre- and post-exploration measures, including assessing adult attachment styles and partners' perception of support provided during the task. Three independent coders watched the videos of couples interacting and rated partners' support provision behavior. We utilized West and Kenny's (2011) truth and bias model to compare judgments (partners' perception of support received during the exploration task) with so-defined truth (combined rankings from coders). We used regression analysis to investigate how attachment orientation moderates the perception of support provision. On average, individuals tended to over-perceive helpfulness and under-perceive intrusiveness. Attachment avoidance was not a significant predictor of directional bias for helpfulness and intrusiveness. Results for the second exploratory hypothesis show those higher on attachment anxiety to have a weaker bias in underperceiving intrusiveness.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00014039
- Subject Headings
- Attachment behavior, Bias, Perception
- Format
- Document (PDF)
- Title
- Visual wavelength discrimination by the loggerhead turtle, Caretta caretta.
- Creator
- Young, Morgan, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Little is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles...
Show moreLittle is known about the visual capabilities of marine turtles. The ability to discriminate between colors has not been adequately demonstrated on the basis of behavioral criteria. I used a three-part methodology to determine if color discrimination occurred. FIrst, I exposed naèive, light-adapted hatchlings to either a blue, green or yellow light. I manipulated light intensity to obtain a behavioral phototaxis threshold to each color, which provided a range of intensities we knew turtles could detect. Second, I used food to train older turtles to swim toward one light color, and then to discriminate between the rewarded light and another light color ; lights were presented at intensities equally above the phototaxis threshold. Lastly, I varied light intensity so that brightness could not be used as a discrimination cue. Six turtles completed this task and showed a clear ability to select a rewarded over a non-rewarded color, regardless of stimulus intensity. Turtles most rapidly learned to associate shorter wavelengths (blue) with food. My results clearly show loggerheads have color vision. Further investigation is required to determine how marine turtles exploit this capability.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3352879
- Subject Headings
- Color vision, Visual discrimination, VIsual perception, Selectivity (Psychology), Photoreceptors, Loggerhead turtle, Orientation, Sea turtles, Orientation, Animal navigation
- Format
- Document (PDF)