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- Title
- Which Way is It? Spatial Navigation and the Genetics of Head Direction Cells.
- Creator
- Lora, Joan C., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
From locating a secure home, foraging for food, running away from predators, spatial navigation is an integral part of everyday life. Multiple brain regions work together to form a three-dimensional representation of our environment; specifically, place cells, grid cells, border cells & head direction cells are thought to interact and influence one another to form this cognitive map. Head direction (HD) cells fire as the animal moves through space, according to directional orientation of the...
Show moreFrom locating a secure home, foraging for food, running away from predators, spatial navigation is an integral part of everyday life. Multiple brain regions work together to form a three-dimensional representation of our environment; specifically, place cells, grid cells, border cells & head direction cells are thought to interact and influence one another to form this cognitive map. Head direction (HD) cells fire as the animal moves through space, according to directional orientation of the animal’s head with respect to the laboratory reference frame, and are therefore considered to represent the directional sense. Interestingly, inactivation of head direction cell-containing brain regions has mixed consequences on spatial behavior. Current methods of identifying HD cells are limited to in vivo electrophysiological recordings in a dry-land environment. We first developed a dry-land version of the MWM in order to carry out behavioral-recording paired studies. Additionally, to learn about HD cells function we quantified expression of neuronal activation marker (c-Fos), and L-amino acid transporter 4 (Lat4) in neurons found within the HD cell dense anterodorsal thalamic nucleus (ADN) in mice after exploratory behavior in an open field, or forward unidirectional movement on a treadmill. We hypothesize that the degree to which ADN neurons are activated during exploratory behavior is influenced by the range of heading directions sampled. Additionally, we hypothesize that c-Fos and Lat4 are colocalized within ADN neurons following varying amounts of head direction exposure. Results indicate that following free locomotion of mice in an open field arena, which permitted access to 360° of heading, a greater number of ADN neurons express c-Fos protein compared to those exposed to a limited range of head directions during locomotion in a treadmill. These findings suggest that the degree of ADN neuronal activation was dependent upon the range of head directions sampled. We observed a high degree of colocalization of c-Fos and Lat4 within ADN suggesting that Lat4 may be a useful tool to manipulate neuronal activity of HD cells. Identifying genetic markers specific to ADN helps provide an essential understanding of the spatial navigation system, and supports development of therapies for cognitive disorders affecting navigation.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004931, http://purl.flvc.org/fau/fd/FA00004931
- Subject Headings
- Psychobiology., Spatial behavior in animals., Mice as laboratory animals., Navigation--Psychological aspects., Computational intelligence.
- Format
- Document (PDF)
- Title
- Use of Ground Penetrating Radar (GPR) in a Study on Beach Morphodynamics at Red Reef Beach, Boca Raton, Florida.
- Creator
- Camara dos Santos Porto, Sabrina, Briggs, Tiffany Roberts, Comas, Xavier, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
The internal architecture of a beach system can provide clues into the processes involved in its formation, including depositional processes, and/or driving mechanisms (Billy et al., 2014). Several unique events such as cold fronts or Hurricane Irma caused conditions that resulted in erosion and accretion changes in Red Reef Beach - Boca Raton, throughout the year of 2017. Since the lateral extent of these changes is difficult to evaluate using traditional methods such as coring, a Ground...
Show moreThe internal architecture of a beach system can provide clues into the processes involved in its formation, including depositional processes, and/or driving mechanisms (Billy et al., 2014). Several unique events such as cold fronts or Hurricane Irma caused conditions that resulted in erosion and accretion changes in Red Reef Beach - Boca Raton, throughout the year of 2017. Since the lateral extent of these changes is difficult to evaluate using traditional methods such as coring, a Ground Penetrating Radar (GPR) was tested, which allows for a good lateral resolution (cm scale), to image the distribution and evolution of these sediments. The objectives of this study were to 1) explore the lateral variability in the internal architecture of sediments in Red Reef beach in Boca Raton (FL) using an array of ground penetrating radar (GPR) measurements constrained with coring and sediment analysis; 2) explore how dynamics of erosion and accretion induced by changes in wave activity and related to tide variation and storm events, may affect surface topography and the sedimentary internal architecture of beach deposits, using RTK GPS and GPR time-lapse measurements; 3) to explore changes in the lateral extent of the freshsaltwater interface along the beach profile in relation to tide variation and storm events. Reflectors identified in the GPR images showed some evidence of erosional and accretionary surfaces preserved in Red Reef beach. These measurements were repeated over time coinciding with certain events (such as Hurricane Irma) to explore their effects in terms of sediment erosion and accretion as reflected in changes in topography (using time-lapse GPS-RTK measurements), and changes in the internal sedimentary architecture (using time-lapse GPR measurements). The datasets collected also revealed the temporal evolution of the salt-freshwater interface, showing how the lateral extent of saltwater saturated sediment (inferred from areas of GPR signal attenuation along the profiles) evolved over time. This study shows the potential of GPR to provide information about beach sediment processes and dynamics at resolutions beyond traditional measurements (such as coring). It also shows the importance of combining methods that are complementary, such as the use of RTK GPS to explore changes in topography, and GPR that provides information on subsurface sedimentary architecture and the mechanism of change such as post-storm recovery. This study has implications for better understanding changes in coastal sedimentary deposits and processes, both at the subsurface, particularly after high-energy events, such as hurricanes, that result in rapid changes in erosion and/or accretion of sediments.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00005947
- Subject Headings
- Dissertations, Academic -- Florida Atlantic University, Beaches--Florida, Ground penetrating radar., Sediments (Geology)--Analysis.
- Format
- Document (PDF)
- Title
- Using Low-Cost Multi-Depth Samplers to Characterize the Variability of Specific Conductance in Coastal South Florida Beaches.
- Creator
- Shaver, Kyle David, Root, Tara, Briggs, Tiffany Roberts, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
- Abstract/Description
-
A small body of saline rich water rests in the saturated zone between the foredune and the shoreline at certain beaches. This region is beneath the water table and the top of the fresher groundwater, known as the Upper Saline Plume (USP). The USP is significant because density driven flow and chemical fluxes between freshwater, rainwater, and seawater contribute to biogeochemical processes in the subterranean estuary (Duque et al. 2020). The occurrence of the USP has been observed along...
Show moreA small body of saline rich water rests in the saturated zone between the foredune and the shoreline at certain beaches. This region is beneath the water table and the top of the fresher groundwater, known as the Upper Saline Plume (USP). The USP is significant because density driven flow and chemical fluxes between freshwater, rainwater, and seawater contribute to biogeochemical processes in the subterranean estuary (Duque et al. 2020). The occurrence of the USP has been observed along beaches that have a moderate to gentle slope, fine to medium grain size, and higher wave energy. The goal of this study was to determine if conditions for the presence of USP are consistent throughout different coastal beaches in southeast Florida while mapping the groundwater salinity across the beach. To identify the existence and delimit the boundary interface of the USP in the southeastern coast of Florida, multi–depth samplers were designed, built, and deployed along cross-shore transects at Jupiter and Gulfstream Beaches in Palm Beach County, FL. Groundwater samples were extracted along the transects to measure specific conductance. Although this study did not confirm the existence of the USP in South Florida beaches, an intermediate zone of water that is in-between the specific conductance ranges of relatively freshwater and relatively salty water was identified. Furthermore, the size of this intermediate zone was corresponded with beach slope, showing larger intermediate zones for steeper slopes and vice versa. Finally, temporal changes in the location and morphology of this intermediate zone were also identified in relation to a distinct disturbance event (Hurricane Isaias) which resulted in elevated ocean water levels.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013625
- Subject Headings
- Beaches--Florida, Freshwater, Seawater, Water resources--Management
- Format
- Document (PDF)
- Title
- Inlet-Adjacent Shoreline Behavior at Three Stabilized Inlets in Palm Beach County, FL (USA).
- Creator
- Vandamas, Edward A, Briggs, Tiffany Roberts, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Shorelines are a primary source of attraction for the nearly two million tourists who visit Palm Beach County annually. Many of Palm Beach County beaches are located on barrier islands, separated by a series of inlets which serve as access points to the Intracoastal Waterway. However, inlets are often cited as a source of erosion, through interruption of littoral drift and interaction with nearshore hydrodynamics (e.g., causing wave diffraction or refraction). In an effort to mitigate...
Show moreShorelines are a primary source of attraction for the nearly two million tourists who visit Palm Beach County annually. Many of Palm Beach County beaches are located on barrier islands, separated by a series of inlets which serve as access points to the Intracoastal Waterway. However, inlets are often cited as a source of erosion, through interruption of littoral drift and interaction with nearshore hydrodynamics (e.g., causing wave diffraction or refraction). In an effort to mitigate potential negative impacts of the economically important tidal inlets, Palm Beach County has installed a sand transfer plant (STP) at two inlet locations, the Lake Worth Inlet and the South Lake Worth Inlet. Through analysis of annual aerial photography and beach profile surveys taken between 2000 and 2009, this study will determine what effect, if any, these sand transfer plants are having on the inlet-adjacent shorelines north and south of the two inlets with STP, as well as an inlet without an STP (Boca Inlet). This study hopes to increase the understanding of shoreline dynamics in Palm Beach County, which could recognize important alongshore patterns, such as the occurrence of erosional hot spots, to assist in future mitigation efforts.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004554, http://purl.flvc.org/fau/fd/FA00004554
- Subject Headings
- Beach erosion -- Florida -- Lake Worth Inlet -- Prevention, Beach erosion -- Florida -- South Lake Worth Inlet -- Prevention, Coastal changes -- Florida -- Palm Beach County, Coastal zone management -- Florida -- Palm Beach County, Geodynamics, Soil conservation -- Florida -- Lake Worth Inlet, Soil conservation -- Florida -- South Lake Worth Inlet, Sustainable development
- Format
- Document (PDF)
- Title
- SELECTIVE MODULATION OF SMALL CONDUCTANCE CALCIUM ACTIVATED POTASSIUM CHANNELS IN C57BL/6J MICE RESCUES MEMORY AND ATTENTION DISORDERS IN KETAMINE-INDUCED PSYCHOSIS: A NEW THERAPEUTIC APPROACH.
- Creator
- Rice, Claire A., Stackman, Jr. Robert W., Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
- Abstract/Description
-
Small conductance Ca2+-activated K+ (SK) channels are expressed throughout brain regions important for long-term memory. They constrain the intrinsic excitability of neurons by enhancing afterhyperpolarization, shape glutamatergic synaptic potentials and limit induction of NMDA receptor-dependent synaptic plasticity. Behaviorally, SK channels modulate learning and memory encoding. It is hypothesized that SK channels influence cognitive symptoms of psychosis including executive functioning,...
Show moreSmall conductance Ca2+-activated K+ (SK) channels are expressed throughout brain regions important for long-term memory. They constrain the intrinsic excitability of neurons by enhancing afterhyperpolarization, shape glutamatergic synaptic potentials and limit induction of NMDA receptor-dependent synaptic plasticity. Behaviorally, SK channels modulate learning and memory encoding. It is hypothesized that SK channels influence cognitive symptoms of psychosis including executive functioning, working memory, and selective attention. Theories of psychosis currently posit that symptoms of psychosis are a result of dopaminergic hyperfunction, and glutamatergic dysregulation which can be induced following administration of the NMDA receptor antagonist, ketamine. Initial experiments confirmed that sub-chronic treatment with KET produced significant impairment of object recognition memory, trace fear memory, and latent inhibition compared to SAL mice. A comparison of ketamine dosing regimens revealed the necessity for sub-chronic/chronic dosing on a consistent schedule with a wash out period, to obtain long-lasting attention and memory impairment. These experiments revealed for the first time that sub-chronic KET treatment elicited a new phenotype in male C57BL/6J mice: audible vocalizations. KET mice emitted audible vocalizations within 10 min of receiving KET injections, and vocalizations were detected up to 30 min after injection. Experiments conducted to determine the efficacy of SK channel agonists and antagonists on SK channels to modulate attention and memory in the ketamineinduced model of psychosis in C57BL/6J mice demonstrated for the first time that the SK2 channel activator, CyPPA, significantly reduced memory impairment and decreased the attention deficit of KET mice. A new method of analysis for trace fear conditioning freezing responses permitted a more accurate measurement of the ability of mice to discriminate the predicted delivery of shock during trace versus CS intervals. The application of the novel analytical method further demonstrated that KET mice failed to accurately discriminate these intervals, due to their impaired attention and acquisition of the trace conditioned response. This study examined the efficacy of SK channel drugs to rescue cognitive impairments in a pharmacological mouse model of schizophrenia. The results indicate that SK2 subunit activators and blockers, may provide a new therapeutic treatment for memory impairment and attention deficits seen in schizophrenic disorders.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013624
- Subject Headings
- Calcium-activated potassium channels, Calcium-dependent potassium channels, Mice, Ketamine, Psychoses
- Format
- Document (PDF)
- Title
- Storm-Induced Neashore Sediment Transport.
- Creator
- Warren, William F., Briggs, Tiffany Roberts, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Each year storms impact coastal areas, sometimes causing significant morphologic change. Cold fronts are associated with increased wave energy and frequently occur during the winter months along many coasts, such as the Atlantic and Gulf of Mexico. The higher wave energy can be responsible for a large quantity of the sediment transport resulting in rapid morphologic change. Using streamer traps, the vertical distribution of onshore-directed sediment transport during two different cold fronts...
Show moreEach year storms impact coastal areas, sometimes causing significant morphologic change. Cold fronts are associated with increased wave energy and frequently occur during the winter months along many coasts, such as the Atlantic and Gulf of Mexico. The higher wave energy can be responsible for a large quantity of the sediment transport resulting in rapid morphologic change. Using streamer traps, the vertical distribution of onshore-directed sediment transport during two different cold fronts on two low-wave energy beaches (i.e., along the northern Yucatan and southeast Florida) were compared with the resulting morphologic change. The objectives of this study are to: 1) analyze the grain size distribution (statistics) of sediment transported during a cold front, 2) compare the vertical sediment distribution throughout the water column, and 3) compare characteristics of bed sediment to the sediment within the water column. Understanding the changing grain size distribution of bottom sediments in comparison to directional transport (throughout the water column) should help determine the sediment fraction(s) being eroded or deposited, which could greatly improve predictions of storm-induced morphology change.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004830, http://purl.flvc.org/fau/fd/FA00004830
- Subject Headings
- Coast changes--Mathematical models., Coastal zone management., Geomorphology., Sediment transport--Analysis., Coastal engineering--Mathematical models.
- Format
- Document (PDF)
- Title
- Selective Activation of the SK1 Subtype of Small Conductance Ca2+ Activated K+ Channels by GW542573X in C57BL6J Mice Impairs Hippocampal-dependent Memory.
- Creator
- Rice Kuchera, Claire A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
SK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal...
Show moreSK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal-dependent object memory, contextual and cued conditioning, and trace fear conditioning was examined. The results demonstrated that pre- but not post-training systemic administration of GW542573X impaired object memory and trace fear memory in mice 24 h after training. Contextual and cued fear memory were not disrupted. These current data suggest that activation of SK1 subtype-containing SK channels impairs long-term memory. These results are consistent with converging evidence that SK channel activation suppressed behaviorally triggered synaptic plasticity necessary for encoding hippocampal-dependent memory.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004541, http://purl.flvc.org/fau/fd/FA00004541
- Subject Headings
- Cellular control mechanisms, Cognitive neuroscience, Cognitive psychology, Hippocampus (Brain), Mice as laboratory animals, Neurotransmitter receptors
- Format
- Document (PDF)
- Title
- Mapping the Fresh-Saltwater Transition Zone Across the Beach Environment Using Ground-Penetrating Radar (GPR).
- Creator
- Becker, Joseph Michael, Roberts Briggs, Tiffany, Comas, Xavier, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
As sea level rises, saltwater migration can threaten coastal ecosystems and beach-dune environments, which negatively impacts coastal flora. This study uses ground penetrating radar (GPR) to evaluate the spatiotemporal variability of saltwater migration in the near shore at high lateral resolution (i.e. cm) by using daily micro tidal cycles as analogs to infer saltwater migration. Time-lapse GPR profiles were collected at low and high tide capturing phase lags of the tidal flux through...
Show moreAs sea level rises, saltwater migration can threaten coastal ecosystems and beach-dune environments, which negatively impacts coastal flora. This study uses ground penetrating radar (GPR) to evaluate the spatiotemporal variability of saltwater migration in the near shore at high lateral resolution (i.e. cm) by using daily micro tidal cycles as analogs to infer saltwater migration. Time-lapse GPR profiles were collected at low and high tide capturing phase lags of the tidal flux through different substrates. GPR measurements were collected at two sites in Miami with contrasting lithologies: a) Crandon Park, composed of unconsolidated sand; and b) the Barnacle Historic State Park, composed of the Miami Limestone Formation. Laboratory-scale GPR measurements were collected over samples mimicking field conditions. The results may be helpful to identify regions vulnerable to saltwater migration in the near shore based on lithological variability, and to mitigate negative impacts for flora in beach-dune habitats during sea level rise.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013183
- Subject Headings
- Ground penetrating radar, Saltwaters, Seashore ecology, Coastal ecology
- Format
- Document (PDF)
- Title
- Hippocampal CA1 activation during object memory encoding in the novel object recognition task.
- Creator
- Cinalli, David A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal...
Show moreTranscription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004436, http://purl.flvc.org/fau/fd/FA00004436
- Subject Headings
- Association of ideas, Cellular control mechanisms, Cellular signal transduction, Episodic memory, Hippocampus (Brain) -- Physiology, Human information processing, Mice as laboratory animals
- Format
- Document (PDF)
- Title
- Hurricane Irma Impact and Post-Storm Beach Morphology Evolution in Boca Raton, FL.
- Creator
- Hart, Richard M., III, Roberts Briggs, Tiffany, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
Beach morphology changes naturally with seasonal and event-driven variability in the wave climate, as well as due to anthropogenic activities such as erosion mitigation efforts. In 2017, category four Hurricane Irma caused beach erosion and dune overwash in Boca Raton, FL. Immediate post-storm perigean spring tides coupled with typical winter high-wind conditions imposed a regime of spatially and temporally extended meteorologic and morphologic variability. This study evaluates the...
Show moreBeach morphology changes naturally with seasonal and event-driven variability in the wave climate, as well as due to anthropogenic activities such as erosion mitigation efforts. In 2017, category four Hurricane Irma caused beach erosion and dune overwash in Boca Raton, FL. Immediate post-storm perigean spring tides coupled with typical winter high-wind conditions imposed a regime of spatially and temporally extended meteorologic and morphologic variability. This study evaluates the morphologic evolution and post-storm recovery in the first year following Hurricane Irma. Time-series topographic surveys and surface sediment samples were collected. Patterns of accretion and erosion were evaluated with regionally measured water and wind levels. Recovery morphology was generally through berm-building, but lacked shoreline stability. Storm impact regime, mitigation structures, and sediment transport patterns drove the recovery. Total volume lost above the 0 m contour due to the storm was not fully recovered within the year, with a large volume measured in the south.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013213
- Subject Headings
- Hurricane Irma, 2017, Boca Raton (Fla.), Beach erosion
- Format
- Document (PDF)
- Title
- Commercialization of high-resolution earth observation satellite remote sensing.
- Creator
- Jarica, Cornelia Christa, Florida Atlantic University, Tata, Robert J., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
The imminent availability of high resolution satellite imagery is causing a paradigm shift in remote sensing. Detente brought about new policy directives in the U.S. and abroad, which opened up for civilian use former Earth observation spy technology down to one meter resolution, previously considered classified and strictly used by the intelligence communities for national security. This study describes a number of new ventures in the private sector which have been formed to launch...
Show moreThe imminent availability of high resolution satellite imagery is causing a paradigm shift in remote sensing. Detente brought about new policy directives in the U.S. and abroad, which opened up for civilian use former Earth observation spy technology down to one meter resolution, previously considered classified and strictly used by the intelligence communities for national security. This study describes a number of new ventures in the private sector which have been formed to launch commercial high resolution systems. The satellites' technical capabilities are analyzed, and application development options for the new imagery are discussed in detail. This new remote sensing data source is also seen within the framework of the larger GeoTechnology Industry to which it belongs, and the author proposes appropriate business strategies for successful commercialization.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15321
- Subject Headings
- Earth resources technology satellites, Remote sensing, Remote-sensing images, Geographic information systems
- Format
- Document (PDF)
- Title
- THE EFFECT OF TEMPERATURE, HYDROGEN ION AND CERTAIN GROWTH SUBSTRATES ON THE ACTIVITY OF THE CELLULOLYTIC ENZYME COMPLEX IN SELECTED MARINE FUNGI.
- Creator
- JENSEN, JAMES ROBERT, Florida Atlantic University, Sguros, Peter L., Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Halosphaeria mediosetigera and Culcitalna achraspora have been studied to elucidate the mechanism by which they degrade cellulosic materials in the sea. H. mediosetigera (700 LC 1), a C1-less variant, was also employed in this work. Standardized shake-cultures were grown on cellulose and cellulose derivatives supplemented with NH4N03, tris(hydroxymethyl)aminomethane and yeast extract in artificial sea water (Lyman and Fleming), pH 7.5, at 25 C. Induced C1 and Cx enzyme and cellobiase...
Show moreHalosphaeria mediosetigera and Culcitalna achraspora have been studied to elucidate the mechanism by which they degrade cellulosic materials in the sea. H. mediosetigera (700 LC 1), a C1-less variant, was also employed in this work. Standardized shake-cultures were grown on cellulose and cellulose derivatives supplemented with NH4N03, tris(hydroxymethyl)aminomethane and yeast extract in artificial sea water (Lyman and Fleming), pH 7.5, at 25 C. Induced C1 and Cx enzyme and cellobiase activities were determined calorimetrically by correlation with cotton fiber weight loss, by the formation of reducing sugars from carboxymethylcellulose and by Glucostat, respectively. Optimum pH values for both Cx enzyme and cellobiase of C. achraspora were 6.0 at 37 C while those for H. mediosetigera (700 LC 1) were 5.0 and 6.0, respectively, at 37 C. In both cultures, Cx enzymes had a variable optimum temperature ( 37-50 C) at pH 6.0, depending on the length of the incubation period, while cellobiases had the same optimum temperature (50 C) at pH 6.0. Thermostability observations on Cx enzyme and cellobiase of C. achraspora showed almost complete deactivation at 100 C in 15 min for the former and 50 C in 15 min for the latter. Thermostability observations on Cx enzyme and cellobiase of H. mediosetigera (700 LC 1) showed almost complete deactivation at 45 C in 15 min for the former and at 50 C in 15 min for the latter. Data indicate that at least three enzymatic functions are involved in cellulose breakdown by these cultures.
Show less - Date Issued
- 1971
- PURL
- http://purl.flvc.org/fcla/dt/13434
- Subject Headings
- Marine fungi, Cellulose--Biodegradation
- Format
- Document (PDF)
- Title
- PLANNING IMPLICATIONS OF THE DIFFERENCES AMONG SQUATTER SETTLEMENTS: THECASE OF THE CARACAS BARRIOS.
- Creator
- CAMPBELL, MARIA INES., Florida Atlantic University, Tata, Robert J., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
This thesis analyzes the characteristics of squatter settlements in Latin America and their potential for improvement. Some of the extensive literature on this subject is reviewed with the purpose of achieving insights into the special case of the Caracas barrios (Venezuelan low-income settlements, in their majority populated by squatters). An empirical analysis is carried out of several variables relating to physical development characteristics of the barrios. A Principal Components...
Show moreThis thesis analyzes the characteristics of squatter settlements in Latin America and their potential for improvement. Some of the extensive literature on this subject is reviewed with the purpose of achieving insights into the special case of the Caracas barrios (Venezuelan low-income settlements, in their majority populated by squatters). An empirical analysis is carried out of several variables relating to physical development characteristics of the barrios. A Principal Components technique with Varimax rotation combined with regression analysis shows the diversity of the barrios and the importance of government approval in the upgrading of housing in these urban areas. These findings are important to planners for the prioritization and allocation of resources.
Show less - Date Issued
- 1984
- PURL
- http://purl.flvc.org/fcla/dt/14209
- Subject Headings
- City planning--Case studies, Squatter settlements--Venezuela--Caracas, Caracas (Venezuela)--Poor
- Format
- Document (PDF)
- Title
- POLARIZED CRYSTAL SPECTRA OF QUADRATE CHROMIUM(III) COMPLEXES.
- Creator
- KLEIN, ROBERT LEWIS, JR., Florida Atlantic University, Perumareddi, Jayarama R., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The polarized crystal spectra of a series of tetragonal trans- diacidobis (ethylenediamine) chromium (III) complexes, trans-[Cr(en)2XY], where X= Y = Br-, H2O, F-, Cl- and X= H2O, Y = OH-, F-, have been measured at liquid nitrogen temperature, achieving better resolution of the split components of the cubic spin-allowed bands, and also definite energy level assignments. The observed band positions have been fitted with the predicted transition energies by the use of the appropriate energy...
Show moreThe polarized crystal spectra of a series of tetragonal trans- diacidobis (ethylenediamine) chromium (III) complexes, trans-[Cr(en)2XY], where X= Y = Br-, H2O, F-, Cl- and X= H2O, Y = OH-, F-, have been measured at liquid nitrogen temperature, achieving better resolution of the split components of the cubic spin-allowed bands, and also definite energy level assignments. The observed band positions have been fitted with the predicted transition energies by the use of the appropriate energy equations for d^3 configuration immersed in tetragonal fields with full configuration interaction. The ligand field parameters, which include the cubic and axial, and the electron correlation parameter B have been evaluated by such a fitting. The derived parameters have been analyzed and their significance discussed. Using thick crystals, we have uncovered a rich doublet structure in some of the complexes and tentative values of the electron correlation parameter C have been obtained for all the complexes.
Show less - Date Issued
- 1971
- PURL
- http://purl.flvc.org/fcla/dt/13454
- Subject Headings
- Chromium
- Format
- Document (PDF)
- Title
- GEOGRAPHIC FACTORS INFLUENCING PUBLIC ACQUISITION OF BEACHFRONT LANDS AS ILLUSTRATED IN PALM BEACH COUNTY, FLORIDA.
- Creator
- FLANAGAN, ROBERT LAWRENCE., Florida Atlantic University, Latham, James P., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
This study evaluates the influence that several geographic factors have upon the public acquisition of beachfront lands. It demonstrates that they have a continuing and very important impact upon efforts to establish public beaches. Factors were analyzed to reveal differing aspects of their influence upon such acquisition, and particularly how they differ in various locations. The analyses illustrate spatial interrelationships that exist among geographic factors relating to the beach lands:...
Show moreThis study evaluates the influence that several geographic factors have upon the public acquisition of beachfront lands. It demonstrates that they have a continuing and very important impact upon efforts to establish public beaches. Factors were analyzed to reveal differing aspects of their influence upon such acquisition, and particularly how they differ in various locations. The analyses illustrate spatial interrelationships that exist among geographic factors relating to the beach lands: physiography, patterns of settlement, political fragmentation, ownership, access, coastal economics, groups and individuals, and governmental roles. The influence of geographic principles are also illustrated by the study. It is demonstrated that awareness of the geographic influences involved in a public beach acquisition program could permit a more knowledgeable analysis of a beach area; thereby contributing to the possibilities for a better program and increased success in acquiring public beaches.
Show less - Date Issued
- 1975
- PURL
- http://purl.flvc.org/fcla/dt/13755
- Subject Headings
- Land use--Florida--Palm Beach County, Beaches--Florida--Palm Beach County, Public lands--Florida--Palm Beach County--Recreational use
- Format
- Document (PDF)
- Title
- New Geometric Large Sets.
- Creator
- Hurley, Michael Robert, Magliveras, Spyros S., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
- Abstract/Description
-
Let V be an n-dimensional vector space over the field of q elements. By a geometric t-[q^n, k, λ] design we mean a collection D of k-dimensional subspaces of V, called blocks, such that every t-dimensional subspace T of V appears in exactly λ blocks in D. A large set, LS [N] [t, k, q^n], of geometric designs is a collection on N disjoint t-[q^n, k, λ] designs that partitions [V K], the collection of k-dimensional subspaces of V. In this work we construct non-isomorphic large sets using...
Show moreLet V be an n-dimensional vector space over the field of q elements. By a geometric t-[q^n, k, λ] design we mean a collection D of k-dimensional subspaces of V, called blocks, such that every t-dimensional subspace T of V appears in exactly λ blocks in D. A large set, LS [N] [t, k, q^n], of geometric designs is a collection on N disjoint t-[q^n, k, λ] designs that partitions [V K], the collection of k-dimensional subspaces of V. In this work we construct non-isomorphic large sets using methods based on incidence structures known as the Kramer-Mesner matrices. These structures are induced by particular group actions on the collection of subspaces of the vector space V. Subsequently, we discuss and use computational techniques for solving certain linear problems of the form AX = B, where A is a large integral matrix and X is a {0,1} solution. These techniques involve (i) lattice basis-reduction, including variants of the LLL algorithm, and (ii) linear programming. Inspiration came from the 2013 work of Braun, Kohnert, Ostergard, and Wassermann, [17], who produced the first nontrivial large set of geometric designs with t ≥ 2. Bal Khadka and Michael Epstein provided the know-how for using the LLL and linear programming algorithms that we implemented to construct the large sets.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004732, http://purl.flvc.org/fau/fd/FA00004732
- Subject Headings
- Group theory., Finite groups., Factorial experiment designs., Irregularities of distribution (Number theory), Combinatorial analysis.
- Format
- Document (PDF)
- Title
- Contrast Effects as a Function of Differential Preadaptation.
- Creator
- Henke, Peter G., Adamson, Robert E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
The purpose of this study was to determine the extent to which preadaptation to differential brightness magnitude affects responses to a constant postadaptation stimulus. Twenty-four male albino rats, one hundred and tweny days old, were divided into four groups and differentially preadapted in Skinner-boxes to 236.90, 77.25, 22.87, and 1.27 apparent foot-candles for 10 minutes, without access to a bar. Immediately following this period the Ss were allowed to respond under continuous...
Show moreThe purpose of this study was to determine the extent to which preadaptation to differential brightness magnitude affects responses to a constant postadaptation stimulus. Twenty-four male albino rats, one hundred and tweny days old, were divided into four groups and differentially preadapted in Skinner-boxes to 236.90, 77.25, 22.87, and 1.27 apparent foot-candles for 10 minutes, without access to a bar. Immediately following this period the Ss were allowed to respond under continuous reinforcement to a postadaptation stimulus of 236.90 apparent foot-candles. Measurement in terms of bar pressing indicated that the four groups extinguished differentially over six days. The control group, for whom the discrepancy bwtween preadaptation magnitude and postadaptation stimulus remained zero, was found most resistant to extiction during this period. Additionally, increases in the discrepancy between the pre- and postadaptation magnitudes led to experimental groups. The implications of these data for the proposition of stimulus definitions in terms of behaviorally effective magnitudes were discussed.
Show less - Date Issued
- 1967
- PURL
- http://purl.flvc.org/fau/fd/FA00012588
- Subject Headings
- Adaptability (Psychology), Extinction (Psychology), Psychophysiology
- Format
- Document (PDF)
- Title
- Contrast Effects: Shifts in Work Load.
- Creator
- Gunn, Diana H., Adamson, Robert E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
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The observation of contrast effects (CE) in response to differential relnforcenent has subsequently elicited a diversity of experimental results and theoretical interpretations. Adaptation Level (AL ) concepts have provided a mechanism for integrating such data within a psychophysical frame-of-reference approach. The application of this approach to the somewhat neglected area of response-produced stimuli associated with effort, suggests that proprioceptive stimuli may be effectively evaluated...
Show moreThe observation of contrast effects (CE) in response to differential relnforcenent has subsequently elicited a diversity of experimental results and theoretical interpretations. Adaptation Level (AL ) concepts have provided a mechanism for integrating such data within a psychophysical frame-of-reference approach. The application of this approach to the somewhat neglected area of response-produced stimuli associated with effort, suggests that proprioceptive stimuli may be effectively evaluated in a simllar manner. Following shifts in the amount of effort required to produce a constant reward magnitude, performance measures demonstrated positive and negative contrast effects (PCE; NCE) in relation to an appropriate control performance. Data analysis suggested that the combined effects of greater effort and shift conditions tended to increase resistance to extinction. The findings are not consistent Kith traditional (e. g., Hull, Spence) concepts with regard to CE and the influence of effort on performance. It is suggested that such effects are more consistent with a contextual, or frame-of- reference, viewpoint.
Show less - Date Issued
- 1967
- PURL
- http://purl.flvc.org/fau/fd/FA00012587
- Subject Headings
- Performance, Reinforcement (Psychology), Reward (Psychology)
- Format
- Document (PDF)
- Title
- DEFENSIBLE SPACE IN A PRIVATELY-OWNED HOUSING PROJECT.
- Creator
- VANHORN, SHARYN J., Florida Atlantic University, Tata, Robert J., Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
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This paper analyzes a high density housing project in terms of its defensible space. The behavior of residents of Citrus Park Homes was seen as indicative of tenant attitudes toward their home project, its sense of community, of safety and security, and pride of ownership. Analysis of this privately-owned project includes a description of the physical structure, spatial characteristics, tenant characteristics and tenant attitudes, as evidenced in interviews with 83 adult residents. Where poor...
Show moreThis paper analyzes a high density housing project in terms of its defensible space. The behavior of residents of Citrus Park Homes was seen as indicative of tenant attitudes toward their home project, its sense of community, of safety and security, and pride of ownership. Analysis of this privately-owned project includes a description of the physical structure, spatial characteristics, tenant characteristics and tenant attitudes, as evidenced in interviews with 83 adult residents. Where poor spatial design and physical structure are evidenced by poor behavior and attitude (lack of recognition or acceptance of territory) changes in the spatial or architectural design were suggested.
Show less - Date Issued
- 1973
- PURL
- http://purl.flvc.org/fcla/dt/13618
- Subject Headings
- Human territoriality, Geographical perception
- Format
- Document (PDF)
- Title
- The Limbic Thalamus.
- Creator
- Hoover, Walter Boyd III, Florida Atlantic University, Vertes, Robert P., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
The thalamus has been traditionally viewed as a structural relay to specific cortical areas behaviorally associated with sensory or motor functions, and thalamic nuclei that function in this manner are referred to as 'relay nuclei·. However. the parts of the thalamus interconnecting limbic association cortices (functionally involved in memory. reward, emotion. and decision making) comprise the midline and intralaminar nuclei. The midline thalamus has not been examined fully at the anatomical,...
Show moreThe thalamus has been traditionally viewed as a structural relay to specific cortical areas behaviorally associated with sensory or motor functions, and thalamic nuclei that function in this manner are referred to as 'relay nuclei·. However. the parts of the thalamus interconnecting limbic association cortices (functionally involved in memory. reward, emotion. and decision making) comprise the midline and intralaminar nuclei. The midline thalamus has not been examined fully at the anatomical, physiological. or behavioral level, and may serve as an important relay between cortical and subcortical structures and the limbic system. The work incorporated into this dissertation included five axonal tract tracing projects that were conducted in the rat. to explore and test the hypothesis that the midline thalamus serves as an important interface between limbic structures including the amygdala. nucleus accumbens. medial prefrontal cortex and hippocampal formation. An important finding was the demonstration of a closed anatomical loop between the hippocampal formation, the ventral medial prefrontal cortex and the ventral midline thalamus: CA 1/subiculum > PLIIL > RE > CA 1/subiculum. Another finding was that 1) the hippocampal formation innervates the entire medial prefrontal cortex; and 2) the hippocampal formation projects more heavily to ventral as compared to dorsal cortices in the mPFC. The paraventricular, parataenial, rhomboid and reuniens nuclei of the midline thalamus were shown to distribute to limbic structures important for cognitive processing: the amygdala, nucleus accumbens, hippocampal formation, parahippocampal cortex, and the prefrontal cortex. Present results demonstrate that the ventral midline nuclei (reuniens and rhomboid) extensively innervate limbic cortical structures (the medial prefrontal cortex and hippocampal formation) whereas dorsal midline nuclei (paraventricular and parataenial) distribute more heavily to subcortical limbic structures (the amygdala and the nucleus accumbens). These midline nuclei may, therefore, relay information between these limbic areas. This connectivity suggests that the midline nuclei could further be subdivided from the intralaminar and relay groups. The midline thalamic nuclei would, therefore, comprise the limbic thalamus.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000861
- Subject Headings
- Neuroanatomy, Limbic system--Physiology, Prefrontal cortex--Physiology, Thalamus--Physiology, Neurotransmitter receptors
- Format
- Document (PDF)