Current Search:  Dissertations, Academic -- Florida Atlantic University (x) » Department of Biological Sciences (x)

View All Items

  • CSV Spreadsheet
(1 - 5 of 5)
Cellular Computation in Primary Visual Cortex
Title
Cellular Computation in Primary Visual Cortex.
Creator
Wilson, Daniel E., Fitzpatrick, David, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Individual neurons in the primary visual cortex respond selectively to different features of visual stimuli, such as spatial orientation or direction of motion. A longstanding goal in systems neuroscience has been to understand the transformations single cells perform as they integrate synaptic inputs to generate spiking output. Recent technological developments have facilitated these lines of investigation by enabling direct measurement of the functional properties of single synaptic inputs...
Show moreIndividual neurons in the primary visual cortex respond selectively to different features of visual stimuli, such as spatial orientation or direction of motion. A longstanding goal in systems neuroscience has been to understand the transformations single cells perform as they integrate synaptic inputs to generate spiking output. Recent technological developments have facilitated these lines of investigation by enabling direct measurement of the functional properties of single synaptic inputs to neurons in the neocortex. It remains an outstanding question as to whether the tuning of single neocortical neurons can be predicted by their excitatory synaptic inputs. Here, I show that excitatory synaptic inputs exhibit significant functional diversity with respect to orientation and direction selectivity. I show that cells can use at least two strategies to overcome this functional diversity to achieve selective responses in the face of broadly tuned excitatory input: enhancing responses to the preferred stimuli and suppressing responses to the non-preferred stimuli. In the case of orientation selectivity, synaptic inputs cluster according to orientation preference and evoke local dendritic nonlinearities, thereby enhancing somatic responses to the preferred direction. For direction selectivity, cells receive excitatory synaptic inputs tuned to the preferred and null directions, but selectively suppress inputs tuned for the null direction to enhance direction selectivity. This suppression comes from direction-tuned GABAergic interneurons that make longrange, intercolumnar projections to enhance direction selectivity.
Show less
Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00004994
Subject Headings
Dissertations, Academic -- Florida Atlantic University
Format
Document (PDF)
A Survey of Gopherus polyphemus Intestinal Parasites in South Florida
Title
A Survey of Gopherus polyphemus Intestinal Parasites in South Florida.
Creator
Huffman, Jessica, Frazier, Evelyn, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Gopherus polyphemus populations are diminishing throughout their range due to urbanization, fragmentation, and poor management of habitats. Increased population densities, poor habitat quality, and lack of fire may influence disease transmission. Parasite roles within wild tortoise populations are largely unknown, despite evidence these pathogens may pose health risks. This study provides a baseline of gopher tortoise endoparasites across South Florida and reports on how varying environmental...
Show moreGopherus polyphemus populations are diminishing throughout their range due to urbanization, fragmentation, and poor management of habitats. Increased population densities, poor habitat quality, and lack of fire may influence disease transmission. Parasite roles within wild tortoise populations are largely unknown, despite evidence these pathogens may pose health risks. This study provides a baseline of gopher tortoise endoparasites across South Florida and reports on how varying environmental and tortoise characteristics may affect endoparasite species prevalence, approximate loads, and overall distributions. Tortoise fecal samples were taken from five differing SF habitats. Seven species of intestinal parasites were discovered from 123 tortoises. Identified parasites include endo-helminths such as cyathostomes, pinworms, ascarids, flukes, and protozoans including Eimeria, Cryptosporidium, and Amoeba species. Significant differences in parasite prevalence and loads were seen between sampling years, seasons, size classes, and sites, however, overall parasite distributions suggest parasitism remains relatively ubiquitous throughout most host and site characteristics.
Show less
Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00005933
Subject Headings
Dissertations, Academic -- Florida Atlantic University, Gopherus polyphemus, Gopher tortoise., Parasites., Florida.
Format
Document (PDF)
Beach dynamics, beachfront development, and climate change: Interactions that impact sea turtle nesting beaches
Title
Beach dynamics, beachfront development, and climate change: Interactions that impact sea turtle nesting beaches.
Creator
Bladow, Rachel A., Milton, Sarah L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Climate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher...
Show moreClimate change will expose sea turtle nests to higher temperatures and more storms; both may negatively impact sea turtle nest success. In this study, unhatched eggs were collected from the Boca Raton, Florida beach and developmental stage at embryonic death determined. Elevated nest temperatures increased embryonic mortality, and the most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34°C. Loggerhead turtles exhibited higher rates of mortality compared to green turtles at temperatures above 34°C. Only loggerhead nests were exposed to inundation, but embryonic mortality did not differ from noninundated nests. Beach profiles across the nesting season were also determined. A major storm altered the beach more in areas of coastal development; however, this was impacted by a nourishment project and the presence of a structured inlet. Future management strategies may need to protect sea turtle nests from extended periods at elevated temperatures.
Show less
Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00005926
Subject Headings
Dissertations, Academic -- Florida Atlantic University, Sea turtles--Ecology., Loggerhead turtle--Florida., Sea turtles--Nests., Climate change
Format
Document (PDF)
An Assessment of Fecal Pollution in the St. Lucie Estuary and Indian River Lagoon
Title
An Assessment of Fecal Pollution in the St. Lucie Estuary and Indian River Lagoon.
Creator
Perricone, Carlie S., McCarthy, Peter J., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Contamination of recreational waters with fecal waste, indicated by the presence of enterococci, can have consequences for human and ecosystem health. The difficulty in determining the extent and origin of fecal pollution in dynamic estuarine systems is compounded by contributions from sources including septic tanks and agricultural runoff. This study investigated fecal pollution at five sites with variable hydrological conditions in the St. Lucie Estuary and Indian River Lagoon. The...
Show moreContamination of recreational waters with fecal waste, indicated by the presence of enterococci, can have consequences for human and ecosystem health. The difficulty in determining the extent and origin of fecal pollution in dynamic estuarine systems is compounded by contributions from sources including septic tanks and agricultural runoff. This study investigated fecal pollution at five sites with variable hydrological conditions in the St. Lucie Estuary and Indian River Lagoon. The distribution and occurrence of enterococci was assessed using traditional cultivation. A human-associated microbial source tracking assay was validated and applied in these estuaries using qPCR. Results demonstrated a correlation between enterococci concentrations, rainfall, and salinity. The human-associated assay was sensitive and specific in the lab; however, human fecal pollution was not detected in the field even though samples contained high levels of enterococci. This study highlights the importance of expanding the range of water quality assessment.
Show less
Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00005023, http://purl.flvc.org/fau/fd/FA00005932
Subject Headings
Dissertations, Academic -- Florida Atlantic University, Indian River (Fla. : Lagoon), Saint Lucie River Estuary (Fla.), Enterococcus., Fecal matter., Estuarine pollution.
Format
Document (PDF)
Population Structure and Gene Expression of the Coral Montastraea cavernosa in the Northern Florida Reef Tract
Title
Population Structure and Gene Expression of the Coral Montastraea cavernosa in the Northern Florida Reef Tract.
Creator
Dodge, Danielle, Voss, Joshua, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Coral reefs on Florida’s Reef Tract (FRT) are susceptible to many anthropogenic influences including controlled freshwater discharges and agricultural runoff as well as high natural environmental variability from seasonal rainfall, runoff and upwelling. To better understand coral population structure and responses to sublethal stressors, populations of the scleractinian coral Montastraea cavernosa in the northern FRT were examined using a combination of genomic and transcriptomic techniques....
Show moreCoral reefs on Florida’s Reef Tract (FRT) are susceptible to many anthropogenic influences including controlled freshwater discharges and agricultural runoff as well as high natural environmental variability from seasonal rainfall, runoff and upwelling. To better understand coral population structure and responses to sublethal stressors, populations of the scleractinian coral Montastraea cavernosa in the northern FRT were examined using a combination of genomic and transcriptomic techniques. Microsatellite genetic markers identified high local retention among sites and a slight southward gene flow. An in-situ temporal gene expression analysis utilizing a tag-based sequencing transcriptomic approach was used to analyze baseline coral health at St. Lucie Reef (SLR), off Stuart, FL. Temporal variation had the greatest influence of differential gene expression among M. cavernosa at SLR. Results will be shared with local resource managers and coupled with a complementary ex-situ experimental trial.
Show less
Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00005920
Subject Headings
Dissertations, Academic -- Florida Atlantic University, Montastraea, Coral reef ecology--Florida., Corals--Effect of stress on, Gene expression--Analysis.
Format
Document (PDF)