Current Search: info:fedora/islandora:personCModel (x) » Caribbean Area (x) » Department of Educational Leadership and Research Methodology (x)
View All Items
(18,461 - 18,480 of 24,327)
Pages
- Title
- Spatial coherence methods in undersea image formation and detection.
- Creator
- Caimi, F. M., Bailey, B. C., Blatt, J. H., Harbor Branch Oceanographic Institute
- Date Issued
- 1996
- PURL
- http://purl.flvc.org/FCLA/DT/3183697
- Subject Headings
- Underwater imaging systems, Image Quality
- Format
- Document (PDF)
- Title
- SPATIAL ECOLOGY OF BOBCATS (LYNX RUFUS) ON EVERGLADES TREE ISLANDS.
- Creator
- Buckman, Katherine, Dom, Nathan, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Bobcats (Lynx rufos) that inhabit tree islands of the Everglades, an expansive wetland in southern Florida. Bobcats are understudied in Florida and wetland ecosystems, and my objective was to identify factors driving their use of tree islands. I hypothesized that tree island size, distance between islands, and clusters of islands might influence occupancy. Additionally, I tested for effects of water levels and the Burmese Python invasion on bobcat occupancy. I built detection histories using...
Show moreBobcats (Lynx rufos) that inhabit tree islands of the Everglades, an expansive wetland in southern Florida. Bobcats are understudied in Florida and wetland ecosystems, and my objective was to identify factors driving their use of tree islands. I hypothesized that tree island size, distance between islands, and clusters of islands might influence occupancy. Additionally, I tested for effects of water levels and the Burmese Python invasion on bobcat occupancy. I built detection histories using 1,855 bobcat images from camera traps set on 87 tree islands in a -2,350 km2 managed conservation area from 2005-2019 and tested hypotheses about bobcat use relative to habitat and hydrologic covariates. Bobcat occupancy was significantly diminished when Burmese python densities exceeded 2.5 pythons/km2• Occupancy probability also increased with increasing densities of tree islands around the focal island. Effects of high water levels were less clear, but suggested a slight reduction in island occupancy with deeper water in the surrounding wetlands. My results suggest that managing for high tree island density and low densities of Burmese pythons will have stronger effects on bobcat habitat use than specific water levels.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013846
- Subject Headings
- Lynx rufus, Bobcat, Spatial ecology, Everglades (Fla.)
- Format
- Document (PDF)
- Title
- THE SPATIAL FRAMEWORK OF FORM PERCEPTION: INDIVIDUAL DIFFERENCES WITH RESPECT TO PHENOMENAL AND RETINAL DETERMINATION OF SPATIAL REFERENCE.
- Creator
- GOLD, LEON SAMUEL, Florida Atlantic University
- Abstract/Description
-
Rock's procedure for separating the effect of objective and retinal spatial reference by varying stimulus orientation and body posture was used in conjunction with the "same-different" reaction time paradigm. It was predicted that the individual differences in perceptual processing (analytic and structural) obtained by Hock (1973) would involve different determinants of spatial reference, these being retinal reference for analytic processing and objective reference for structural processing....
Show moreRock's procedure for separating the effect of objective and retinal spatial reference by varying stimulus orientation and body posture was used in conjunction with the "same-different" reaction time paradigm. It was predicted that the individual differences in perceptual processing (analytic and structural) obtained by Hock (1973) would involve different determinants of spatial reference, these being retinal reference for analytic processing and objective reference for structural processing. The results show that analytic subjects as hypothesized, referenced perceptual information to a retinal coordinate system. Structural subjects however, seemed to reference perceptual information to both objective and retinal coordinates. The results for structural subjects were attributed to the unexpected finding that subjects who were structural while upright, became analytic when in a reclining position. The latter finding suggested that Rock's methodology for separating the effects of retinal and objective orientation relies on the subjects employing the same mode of processing in all bodily postures.
Show less - Date Issued
- 1974
- PURL
- http://purl.flvc.org/fcla/dt/13649
- Subject Headings
- Form perception, Orientation (Psychology), Recognition (Psychology), Visual perception
- Format
- Document (PDF)
- Title
- SPATIAL NETWORK BIG DATA APPROACHES TO EMERGENCY MANAGEMENT INFORMATION SYSTEMS.
- Creator
- Herschelman, Roxana M., Yang, KwangSoo, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
Emergency Management Information Systems (EMIS) are defined as a set of tools that aid decision-makers in risk assessment and response for significant multi-hazard threats and disasters. Over the past three decades, EMIS have grown in importance as a major component for understanding, managing, and governing transportation-related systems. To increase resilience against potential threats, the main goal of EMIS is to timely utilize spatial and network datasets about (1) locations of hazard...
Show moreEmergency Management Information Systems (EMIS) are defined as a set of tools that aid decision-makers in risk assessment and response for significant multi-hazard threats and disasters. Over the past three decades, EMIS have grown in importance as a major component for understanding, managing, and governing transportation-related systems. To increase resilience against potential threats, the main goal of EMIS is to timely utilize spatial and network datasets about (1) locations of hazard areas (2) shelters and resources, (3) and how to respond to emergencies. The main concern about these datasets has always been the very large size, variety, and update rate required to ensure the timely delivery of useful emergency information and response for disastrous events. Another key issue is that the information should be concise and easy to understand, but at the same time very descriptive and useful in the case of emergency or disaster. Advancement in EMIS is urgently needed to develop fundamental data processing components for advanced spatial network queries that clearly and succinctly deliver critical information in emergencies. To address these challenges, we investigate Spatial Network Database Systems and study three challenging Transportation Resilience problems: producing large scale evacuation plans, identifying major traffic patterns during emergency evacuations, and identifying the highest areas in need of resources.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013576
- Subject Headings
- Emergency management, Big data, Emergency management--Information technology
- Format
- Document (PDF)
- Title
- SPATIAL NETWORK BIG DATABASE APPROACH TO RESOURCE ALLOCATION PROBLEMS.
- Creator
- Qutbuddin, Ahmad, Yang, KwangSoo, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
Resource allocation for Spatial Network Big Database is challenging due to the large size of spatial networks, variety of types of spatial data, a fast update rate of spatial and temporal elements. It is challenging to learn, manage and process the collected data and produce meaningful information in a limited time. Produced information must be concise and easy to understand. At the same time, the information must be very descriptive and useful. My research aims to address these challenges...
Show moreResource allocation for Spatial Network Big Database is challenging due to the large size of spatial networks, variety of types of spatial data, a fast update rate of spatial and temporal elements. It is challenging to learn, manage and process the collected data and produce meaningful information in a limited time. Produced information must be concise and easy to understand. At the same time, the information must be very descriptive and useful. My research aims to address these challenges through the development of fundamental data processing components for advanced spatial network queries that clearly and briefly deliver critical information. This thesis proposal studied two challenging Spatial Network Big Database problems: (1) Multiple Resource Network Voronoi Diagram and (2) Node-attributed Spatial Graph Partitioning. To address the challenge of query processing for multiple resource allocation in preparing for or after a disaster, we investigated the problem of the Multiple Resource Network Voronoi Diagram (MRNVD). Given a spatial network and a set of service centers from k different resource types, a Multiple Resource Network Voronoi Diagram (MRNVD) partitions the spatial network into a set of Service Areas that can minimize the total cycle-distances of graph-nodes to allotted k service centers with different resource types. The MRNVD problem is important for critical societal applications such as assigning essential survival supplies (e.g., food, water, gas, and medical assistance) to residents impacted by man-made or natural disasters. The MRNVD problem is NP-hard; it is computationally challenging due to the large size of the transportation network. Previous work proposed the Distance bounded Pruning (DP) approach to produce an optimal solution for MRNVD. However, we found that DP can be generalized to reduce the computational cost for the minimum cycle-distance. We extend our prior work and propose a novel approach that reduces the computational cost. Experiments using real-world datasets from five different regions demonstrate that the proposed approach creates MRNVD and significantly reduces the computational cost.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013854
- Subject Headings
- Spatial data infrastructures, Big data--Data processing, Resource allocation, Voronoi polygons
- Format
- Document (PDF)
- Title
- Spatial patterns of interracial marriage in the South Atlantic United States.
- Creator
- Kokoros, Sophia., Florida Atlantic University, Lee, David R.
- Abstract/Description
-
Using Census data, regression analyses were performed at the state level for the South Atlantic region of the U.S. and at the Public Use Microdata Area (PUMA) level for the state of Florida to evaluate possible relationships between the dependent variable, the percentage married households interracial, and several independent variables. Only two of the independent variables examined at the state level were statistically significant: the percent black and the percentage of the population that...
Show moreUsing Census data, regression analyses were performed at the state level for the South Atlantic region of the U.S. and at the Public Use Microdata Area (PUMA) level for the state of Florida to evaluate possible relationships between the dependent variable, the percentage married households interracial, and several independent variables. Only two of the independent variables examined at the state level were statistically significant: the percent black and the percentage of the population that reside in metropolitan areas. No significant relationships could be found at the PUMA level of analysis. Spatial patterns of interracial marriage were evaluated as well. The northernmost states and Florida had the highest percentage of married households interracial. West Virginia and the Carolinas had the lowest rate of intermarriage. PUMAs containing military bases, major universities or those to the South, influenced by migrations from Latin America and the Caribbean, had the greatest percentage of married households interracial.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15694
- Subject Headings
- Interracial marriages--United States.
- Format
- Document (PDF)
- Title
- SPATIAL PROXIMITY, OBJECT FORMATION, AND SELECTIVE ATTENTION.
- Creator
- LALOMIA, MARY JEAN, Florida Atlantic University
- Abstract/Description
-
In these studies subjects judged the curvature direction of one of a pair of parentheses. In one condition the pair of parentheses formed a single object and in a second condition the parentheses formed two objects. The one- and two-object conditions were used to examine the contrasting positions of mental spotlight and object-based theories of attention. Mental spotlight theory holds that attention is allocated to regions in visual space, whereas object-based theory states that attention is...
Show moreIn these studies subjects judged the curvature direction of one of a pair of parentheses. In one condition the pair of parentheses formed a single object and in a second condition the parentheses formed two objects. The one- and two-object conditions were used to examine the contrasting positions of mental spotlight and object-based theories of attention. Mental spotlight theory holds that attention is allocated to regions in visual space, whereas object-based theory states that attention is allocated to objects in visual space. To evaluate the positions of these theories, the retinal proximity between the parentheses was varied. Mental spotlight theory predicts that performance differences, due to the changes of retinal proximity, should be the same regardless of whether the stimuli form one or two objects. Object-based theory predicts that retinal proximity facilitates performance for the one-object condition and retards performance for the two-object condition. The results indicated that retinal proximity facilitated performance for the one-object parentheses but retarded performance for the two-object parentheses. These results support the view that attention is allocated to objects rather than regions in visual space.
Show less - Date Issued
- 1985
- PURL
- http://purl.flvc.org/fcla/dt/14249
- Subject Headings
- Attention--Testing, Attention--Experiments
- Format
- Document (PDF)
- Title
- SPATIAL TRANSFORMATIONS AND SELF-INITIATED ACTIVE MOVEMENT: A DEVELOPMENTAL STUDY.
- Creator
- SULLIVAN, MARJORIE ANN., Florida Atlantic University
- Abstract/Description
-
A spatial transformation task was administered to two groups of children under one of three conditions: active subject-movement, passive subject-movement and stimulus array-rotation. In the younger group (5-7 years) subjects did significantly better in the active subject-movement than in the array-rotation condition. The active-passive distinction was not significant. Performance improved significantly with age. While there were no statistically significant differences between conditions in...
Show moreA spatial transformation task was administered to two groups of children under one of three conditions: active subject-movement, passive subject-movement and stimulus array-rotation. In the younger group (5-7 years) subjects did significantly better in the active subject-movement than in the array-rotation condition. The active-passive distinction was not significant. Performance improved significantly with age. While there were no statistically significant differences between conditions in the older group (8-9 years), a trend toward reversal in level of difficulty between the array-rotation and subject-move conditions was noted. These findings were related to possible differences between young, pre-operational children who depend on topological cues and a stable relationship between the stimulus and the external background context and older, concrete operational children for whom spatial concepts are internalized such that actual movement might compete with imagined movement. Significant sex differences, favoring boys, emerged in the older group.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13897
- Subject Headings
- Space perception in children
- Format
- Document (PDF)
- Title
- SPATIAL VARIATIONS IN MORTGAGE LENDING IN BROWARD COUNTY, FLORIDA.
- Creator
- PHILLIPS, JULIE A., Florida Atlantic University, Schultz, Ronald R., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
An analysis of five loan types from twenty-six lending institutions in 125 census tracts of Broward County revealed that lending was concentrated in coastal and western tracts, less in central tracts. Western tract loan activity was greater than average because this area is undergoing conversion from agricultural to urban land uses. Coastal tracts had greater than average rates because of continued expansion of condominium development. Central tracts are mainly commercial, industrial or lower...
Show moreAn analysis of five loan types from twenty-six lending institutions in 125 census tracts of Broward County revealed that lending was concentrated in coastal and western tracts, less in central tracts. Western tract loan activity was greater than average because this area is undergoing conversion from agricultural to urban land uses. Coastal tracts had greater than average rates because of continued expansion of condominium development. Central tracts are mainly commercial, industrial or lower value single-family dwellings and have large black populations. High positive correlations were found among lending rates and income; moderate positive correlations with age and household size; moderate negative with percent black. Geographic discrimination in lending ("redlining") may be suspected, but insufficient quality and quantity of data render such conclusions tentative.
Show less - Date Issued
- 1983
- PURL
- http://purl.flvc.org/fcla/dt/14156
- Subject Headings
- Mortgage loans--Florida--Broward County
- Format
- Document (PDF)
- Title
- Spatial, temporal, and dietary overlap of leatherback sea turtles (Dermochelys coriacea) and ocean sunfishes (family Molidae).
- Creator
- Desjardin, Nicole A., Florida Atlantic University, Wyneken, Jeanette
- Abstract/Description
-
Investigation of the spatio-temporal movements of leatherback sea turtles (Dermochelys coriacea) and ocean sunfishes (family Molidae), as well as analyses of their prey, support the hypothesis that they may occupy similar ecological niches. This study examined the spatial and temporal occurrences of sunfishes (Mola mola and Masturus lanceolatus) and leatherbacks in the western Atlantic Ocean and assessed dietary overlap. Analyses of leatherback and sunfish distributions, estimated from aerial...
Show moreInvestigation of the spatio-temporal movements of leatherback sea turtles (Dermochelys coriacea) and ocean sunfishes (family Molidae), as well as analyses of their prey, support the hypothesis that they may occupy similar ecological niches. This study examined the spatial and temporal occurrences of sunfishes (Mola mola and Masturus lanceolatus) and leatherbacks in the western Atlantic Ocean and assessed dietary overlap. Analyses of leatherback and sunfish distributions, estimated from aerial surveys, showed greater spatial and temporal overlap along the Northeast coast of North America than in the Gulf of Mexico. Both species co-occur more often during warmer months. Pelagic longline fisheries bycatch data and aerial survey data revealed slightly different trends in spatio-temporal distributions. Nematocysts found within gastrointestinal tract contents of stranded animals indicate that they may feed on similar prey, including cnidarians in the classes Scyphozoa, Hydrozoa, and Cubozoa.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13225
- Subject Headings
- Freshwater fishes--Atlantic Coast (U S )--Geographical distribution, Sea turtles--Atlantic Coast (U S )--Geographical distribution, Animal behavior
- Format
- Document (PDF)
- Title
- Spatially variant and coherent illumination method for undersea object detection and recognition.
- Creator
- Caimi, F. M., Bailey, B. C., Blatt, J. H., Harbor Branch Oceanographic Institute
- Date Issued
- 1998
- PURL
- http://purl.flvc.org/FCLA/DT/3183708
- Subject Headings
- Underwater imaging systems, Underwater light
- Format
- Document (PDF)
- Title
- Spatio-temporal dynamics in the SEIRS epidemic model.
- Creator
- Mei, Lei, Florida Atlantic University, Wille, Luc T.
- Abstract/Description
-
The Susceptible-Exposed-Infected-Recovered-Susceptible (SEIRS) spatial epidemic model is governed by non-linear equations with several parameters related to birth and death, contact rate, disease latency, infectious period, and recycle rate. Both continuum results and lattice results show the existing of disease persistence and critical density. The upper limit of birth and death rate is observed, power spectrum with 1/f profile is discussed. Some other models, as limiting cases of the SEIRS...
Show moreThe Susceptible-Exposed-Infected-Recovered-Susceptible (SEIRS) spatial epidemic model is governed by non-linear equations with several parameters related to birth and death, contact rate, disease latency, infectious period, and recycle rate. Both continuum results and lattice results show the existing of disease persistence and critical density. The upper limit of birth and death rate is observed, power spectrum with 1/f profile is discussed. Some other models, as limiting cases of the SEIRS model, are also studied. Lower limit of birth and death rate for the models without recycle rate has also obtained. Finally two general rules governing epidemic models are summarized. Visualization is available on our web site http://www.cse.fau.edu/~lmei/simulation.html
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15633
- Subject Headings
- Epidemiology--Mathematical models, Demography, Epidemics--Computer simulation
- Format
- Document (PDF)
- Title
- Spatio-temporal modeling of seed dispersal and aquatic plant community restoration in the Kissimmee River floodplain.
- Creator
- Kennard, Stevee., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
This study created an ecological spatial model, using a geographic information system, to visualize the influence of hydrochory on restoration of the three dominant wetland communities of broadleaf marsh, wetland shrub, and wet prairie across the floodplain of the Kissimmee River. Primary parameters incorporated into the model included floodplain hydrology, seed characteristics of buoyancy and dispersal rates, and species flood tolerance. S²rensen's similarity index, comparing spatial...
Show moreThis study created an ecological spatial model, using a geographic information system, to visualize the influence of hydrochory on restoration of the three dominant wetland communities of broadleaf marsh, wetland shrub, and wet prairie across the floodplain of the Kissimmee River. Primary parameters incorporated into the model included floodplain hydrology, seed characteristics of buoyancy and dispersal rates, and species flood tolerance. S²rensen's similarity index, comparing spatial agreement among model output and observed community data, resulted in values of BLM-BB = 0.10, BLM = 0.07, WS = 0.21, and WP = 0.36. The significant discrepancies between modeled and observed community spatial coverage indicated a need for incorporation of more stochastic variables of climatic disturbances, nutrient availability, and soil characteristics. More research on species flood tolerance across smaller spatial scales is also needed, and base data incorporated into the model should also be reliable and consistent if accuracy is to be achieved.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3360797
- Subject Headings
- Seeds, Dispersal, Floodplain ecology, Wetland restoration, Restoration ecology
- Format
- Document (PDF)
- Title
- Spatiotemporal beanformer analysis of neuromagnetic activity in sensorimotor cortex: rhythmic perception, production and sensorimotor coordination.
- Creator
- Ferrari, Paul., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
Research presented in this dissertation has the central aim of applying a novel method of source localization called beamforming to neuromagnetic recordings for characterizing dynamic spatiotemporal activity of sensorimotor brain processes in subjects during rhythmic auditory stimulation, self-paced movement, and two sensorimotor coordination (synchronization and syncopation) tasks known to differentiate on the basis of behavioral stability. Each experimental condition was performed at...
Show moreResearch presented in this dissertation has the central aim of applying a novel method of source localization called beamforming to neuromagnetic recordings for characterizing dynamic spatiotemporal activity of sensorimotor brain processes in subjects during rhythmic auditory stimulation, self-paced movement, and two sensorimotor coordination (synchronization and syncopation) tasks known to differentiate on the basis of behavioral stability. Each experimental condition was performed at different rates resulting in 26 experimental runs per subject. Event-related neural responses were recorded with a whole-head MEG system and characterized in terms of their phase-locked (evoked) and non-phase-locked (induced) activity within the brain using both whole-brain analysis and region of interest (ROI) analysis. The analysis of the auditory conditions revealed that neural activity within extraauditory areas throughout the brain, including sensorimotor cortex, is modulated by rhythmic auditory stimulation. Additionally, the temporal profile of this activity was markedly different between sensorimotor and auditory cortex, possibly revealing different physiological processes, entrained within a common network for representing isochronic auditory events. During self-paced movements cycle-by-cycle dynamics of induced neural activity was measured and consistent neuro-modulation in the form of event-related desynchronization (ERD) and synchronization (ERS) was observed at all rates investigated (0.25 - 1.75Hz). ERD and ERS modulations exhibited dynamic scaling properties on a cycle-by-cycle basis that depended on the period of movement. Activity in the beta- and mu-bands also exhibited patterns of phase locking between sensorimotor locations. Phase locking patterns exhibited abrupt decreases with increases in movement rate., During sensorimotor coordination tasks, the effect of temporal positioning of the auditory stimulus was apparent within sensorimotor cortical sites. This finding offers direct source level support for previous sensor level analysis revealing a differentiation of functional specificity for mu- and beta-band activity (Chen, Ding, Kelso, 2003; Jantzen, Fuchs, Mayville et al., 2001; Mayville, Fuchs, Ding et al., 2001), and may be reflective of specific coupling mechanisms between auditory and sensorimotor networks. The beamformer analysis applied within this dissertation successfully characterized large-scale neural networks during a variety of rhythmic perceptual, motor, and sensorimotor tasks resulting in the general message that information processes across disparate parts of the brain from different sensory, motor, and cognitive modalities appear to have the ability for widespread integration.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/228770
- Subject Headings
- Sensorimotor integration, Perceptual-motor processes, Auditory provoked response, Brain mapping
- Format
- Document (PDF)
- Title
- Spatiotemporal brain dynamics of the resting state.
- Creator
- Rho, Young-Ah., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
Traditionally brain function is studied through measuring physiological responses in controlled sensory, motor, and cognitive paradigms. However, even at rest, in the absence of overt goal-directed behavior, collections of cortical regions consistently show temporally coherent activity. In humans, these resting state networks have been shown to greatly overlap with functional architectures present during consciously directed activity, which motivates the interpretation of rest activity as day...
Show moreTraditionally brain function is studied through measuring physiological responses in controlled sensory, motor, and cognitive paradigms. However, even at rest, in the absence of overt goal-directed behavior, collections of cortical regions consistently show temporally coherent activity. In humans, these resting state networks have been shown to greatly overlap with functional architectures present during consciously directed activity, which motivates the interpretation of rest activity as day dreaming, free association, stream of consciousness, and inner rehearsal. In monkeys, it has been shown though that similar coherent fluctuations are present during deep anesthesia when there is no consciousness. These coherent fluctuations have also been characterized on multiple temporal scales ranging from the fast frequency regimes, 1-100 Hz, commonly observed in EEG and MEG recordings, to the ultra-slow regimes, < 0.1 Hz, observed in the Blood Oxygen Level Dependent (BOLD) signal of functi onal magnetic resonance imaging (fMRI). However, the mechanism for their genesis and the origin of the ultra-slow frequency oscillations has not been well understood. Here, we show that comparable resting state networks emerge from a stability analysis of the network dynamics using biologically realistic primate brain connectivity, although anatomical information alone does not identify the network. We specifically demonstrate that noise and time delays via propagation along connecting fibres are essential for the emergence of the coherent fluctuations of the default network. The combination of anatomical structure and time delays creates a spacetime structure in which the neural noise enables the brain to explore various functional configurations representing its dynamic repertoire., Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the generation o f the slow coherent fluctuations. We find that these fluctuations in the BOLD signal are significantly correlated with the level of neural synchrony implicating that transient interareal synchronizations are the mechanism causing the emergence of the ultra slow coherent fluctuations in the BOLD signal.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/367762
- Subject Headings
- Brain mapping, Sensorimotor integration, Perceptual-motor processes, Intersensory effects, Movement sequences
- Format
- Document (PDF)
- Title
- SPATIOTEMPORAL DYNAMICS OF THE FLORIDA BAY ECOSYSTEM IN RELATION TO CLIMATE CHANGE AND EVERGLADES RESTORATION.
- Creator
- Smith, Mason J., Markwith, Scott H., Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
- Abstract/Description
-
One of the largest restoration programs in the world, the Comprehensive Everglades Restoration Plan (CERP) aims to restore freshwater flows to the Everglades and Florida Bay estuary. Coupled with climate change, future changes from restoration highlight the need to implement an ecosystem-based fisheries management (EBFM) approach in Florida Bay. The Ecopath framework was used to develop and apply a mass-balanced food web model to the spatiotemporal dynamics of hydrological restoration and...
Show moreOne of the largest restoration programs in the world, the Comprehensive Everglades Restoration Plan (CERP) aims to restore freshwater flows to the Everglades and Florida Bay estuary. Coupled with climate change, future changes from restoration highlight the need to implement an ecosystem-based fisheries management (EBFM) approach in Florida Bay. The Ecopath framework was used to develop and apply a mass-balanced food web model to the spatiotemporal dynamics of hydrological restoration and climate change through time. Results suggest Florida Bay is stabilized through large detrital energy pathways and low nutrient inputs, but subject to species distribution shifts due primarily to sea-level rise and salinity variation. A suite of winners and losers predicted provide an opportunity to ensure management strategies are designed appropriately to best achieve desired results for the future of the Florida Bay ecosystem.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013913
- Subject Headings
- Florida Bay (Fla.), Restoration ecology, Climate change
- Format
- Document (PDF)
- Title
- Spatiotemporal dynamics of the human brain associated with transitions in coordination timing.
- Creator
- Wallenstein, Gene Vincent, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
Recent studies have demonstrated that the strategy an individual uses to synchronize motor behavior (e.g. finger flexions) with externally delivered, periodic stimuli depends, in part, on the stimulus presentation rate (Mates, Muller, Radil, and Poppel, 1994; Engstrom, Kelso, and Holroyd, 1995). At rates slower than approximately 0.5 Hz, subjects typically exhibit a reactive-type coordination pattern where the response follows the stimulus by an order of magnitude consistent with typical...
Show moreRecent studies have demonstrated that the strategy an individual uses to synchronize motor behavior (e.g. finger flexions) with externally delivered, periodic stimuli depends, in part, on the stimulus presentation rate (Mates, Muller, Radil, and Poppel, 1994; Engstrom, Kelso, and Holroyd, 1995). At rates slower than approximately 0.5 Hz, subjects typically exhibit a reactive-type coordination pattern where the response follows the stimulus by an order of magnitude consistent with typical response times (i.e. 150-250 milliseconds). At faster rates, however, subjects typically anticipate the impending stimulus in order to synchronize movement with it. In the present study, scalp electroencephalographic (EEG) signals (61 channels) were recorded during a sensorimotor task designed to investigate transitions from one coordination mode to another. We found that subjects exhibited a spontaneous transition from reactive to anticipatory behavior as the stimulus presentation rate increased past some critical frequency. A spatiotemporal analysis of the EEG signals accompanying this task revealed: (1) a widespread frequency component in the EEG matching that of both the stimulus and movement; (2) peak spectral power density over central and antero-central regions in both men and women during reactive behavior; (3) an additional bilaterally distributed frontal component at the most anterior portion of the scalp in men during anticipatory behavior; (4) an additional left fronto-central component which extended posteriorly toward antero-central regions in women during anticipatory behavior; (5) fluctuation enhancement in both the EEG spectral power density and the time lag ($\tau$) between the movement and stimulus accompanying the transition from reactive to anticipatory behavior; (6) that the spectral power density patterns obtained in the primary experimental condition (REACTIVE) were more similar in terms of their spatial distribution with a control condition in which subjects were asked to produce rhythmic movements without benefit of an external stimulus (MOTOR-ONLY) than with a control condition in which subjects passively watched a periodic visual stimulus (STIMULUS-ONLY); (7) that the spectral power density patterns obtained during reactive behavior in the primary experimental condition were more similar spatially to the MOTOR-ONLY condition than du ring anticipatory behavior; and finally (8) that the spectral power density patterns obtained during the experimental condition are not completely accounted for in terms of purely motor- or stimulus-related components. These results are discussed within a common framework of pattern formation instigated by dynamic instabilities in the human brain and behavior.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/12436
- Subject Headings
- Biology, Neuroscience, Psychology, Psychobiology
- Format
- Document (PDF)
- Title
- Spatiotemporal expression of histone acetyltransferases, p300 and CBP, in developing embryonic hearts.
- Creator
- Chen, Guozhen, Zhu, Jing, Lv, Tiewei, Wu, Gang, Sun, Hui-Chao, Huang, Xupei, Tian, Jie
- Date Issued
- 2009
- PURL
- http://purl.flvc.org/fau/fd/FAUIR000153
- Format
- Citation
- Title
- Spatiotemporal patterns of neural fields in a spherical cortex with general connectivity.
- Creator
- Tayefeh, Vahid, Fuchs, Armin, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
- Abstract/Description
-
The human brain consists of billions of neurons and these neurons pool together in groups at different scales. On one hand, these neural entities tend to behave as single units and on the other hand show collective macroscopic patterns of activity. The neural units communicate with each other and process information over time. This communication is through small electrical impulses which at the macroscopic scale are measurable as brain waves. The electric field that is produced collectively...
Show moreThe human brain consists of billions of neurons and these neurons pool together in groups at different scales. On one hand, these neural entities tend to behave as single units and on the other hand show collective macroscopic patterns of activity. The neural units communicate with each other and process information over time. This communication is through small electrical impulses which at the macroscopic scale are measurable as brain waves. The electric field that is produced collectively by macroscopic groups of neurons within the brain can be measured on the surface of the skull via a brain imaging modality called Electroencephalography (EEG). The brain as a neural system has variant connection topology, in which an area might not only be connected to its adjacent neighbors homogeneously but also distant areas can directly transfer brain activity [16]. Timing of these brain activity communications between different neural units bring up overall emerging spatiotemporal patterns. The dynamics of these patterns and formation of neural activities in cortical surface is influenced by the presence of long-range connections between heterogeneous neural units. Brain activity at large-scale is thought to be involved in the information processing and the implementation of cognitive functions of the brain. This research aims to determine how the spatiotemporal pattern formation phenomena in the brain depend on its connection topology. This connection topology consists of homogeneous connections in local cortical areas alongside the couplings between distant functional units as heterogeneous connections. Homogeneous connectivity or synaptic weight distribution representing the large-scale anatomy of cortex is assumed to depend on the Euclidean distance between interacting neural units. Altering characteristics of inhomogeneous pathways as control parameters guide the brain pattern formation through phase transitions at critical points. In this research, linear stability analysis is applied to a macroscopic neural field in a one-dimensional circular and a twodimensional spherical model of the brain in order to find destabilization mechanism and subsequently emerging patterns.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013119
- Subject Headings
- Cerebral cortex, Neural circuitry, Electroencephalography, Neural fields, Spatiotemporal patterns
- Format
- Document (PDF)
- Title
- Spawning aggregation of beardfish Polymixia lowei, in adeep-water sinkhole off the Florida Keys.
- Creator
- Baumberger, Rex E., Jr., Brown-Peterson, N. J., Reed, John K., Gilmore, R. G.
- Date Issued
- 2010
- PURL
- http://purl.flvc.org/fau/fd/FA00007111
- Subject Headings
- Florida Keys (Fla.), Beardfishes, Polymixiidae, Spawning, Sinkholes, Johnson-Sea-Link II (Submarine)
- Format
- Document (PDF)
