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Title: Identification of proteins regulating VLDL sorting into the VLDL Transport Vesicle (VTV) and involved in the biogenesis of the VTV.
Creator: Tiwari, Samata, Siddiqi, Shadab, Zervos, Antonis, Singla, Dinender, Naser, Saleh, University of Central Florida
Abstract / Description: Increased secretion of very low-density lipoprotein (VLDL), a triglyceride-rich lipoprotein, by the liver causes hypertriglyceridemia, which is a major risk factor for the development of atherosclerosis. The rate of VLDL-secretion from the liver is determined by its controlled transport from the endoplasmic reticulum (ER) to the Golgi. The ER-to-Golgi transport of newly synthesized VLDL is a complex multi-step process and is mediated by the VLDL transport vesicle (VTV). Once a nascent VLDL...
Show moreIncreased secretion of very low-density lipoprotein (VLDL), a triglyceride-rich lipoprotein, by the liver causes hypertriglyceridemia, which is a major risk factor for the development of atherosclerosis. The rate of VLDL-secretion from the liver is determined by its controlled transport from the endoplasmic reticulum (ER) to the Golgi. The ER-to-Golgi transport of newly synthesized VLDL is a complex multi-step process and is mediated by the VLDL transport vesicle (VTV). Once a nascent VLDL particle is synthesized in the lumen of the ER, it triggers the process of VTV-biogenesis and this process requires coat complex II (COPII) proteins that mediate the formation of classical protein transport vesicles (PTV). Even though, both VTV and PTV bud off the same ER at the same time and require the same COPII proteins, their cargos and sizes are different. The VTV specifically exports VLDL to the Golgi and excludes hepatic secretory proteins such as albumin and the size of the VTV is larger (~ 100 -120 nm) than PTV to accommodate VLDL-sized particles. These observations indicate (i) the existence of a sorting mechanism at the level of the ER; and (ii) the involvement of proteins in addition to COPII components. This doctoral thesis is focused on identification of proteins regulating VLDL sorting into the VTV and involved in the biogenesis of the VTV. In order to identify proteins present exclusively in VTV, we have characterized the proteome of VTV, which suggest CideB (cell death-inducing DFF45-like effector b) and SVIP (small VCP/P97 interacting protein) as candidates, present in VTV but excluded from PTV. We further confirmed the finding by performing co-immunoprecipitation studies and confocal microscopy studies. CideB, a 26-kDa protein was found to interact with apolipoprotein B100 (apoB 100), the structural protein of VLDL. Moreover, CideB interacts with two of the COPII components, Sar1 and Sec24. VTV generation was examined after blocking CideB by specific antibodies and by silencing CideB in rat primary hepatocytes. Knockdown of CideB in primary hepatocytes showed significant reduction in VTV generation, however, CideB was concentrated in VTV as compared with the ER suggesting its functional role in the sorting of VLDL into the VTV. SVIP, a small (~ 9-kDa) protein was found to interact with Sar1, a COPII component that initiates the budding of vesicles from ER membrane. SVIP has sites for myristoylation and we found increased recruitment of SVIP on ER membrane upon myristic acid (MA) treatment. Sar1 that lacks sites for myristoylation also is recruited more on ER upon myristoylation indicating that SVIP promotes Sar1 recruitment on ER. Additionally, our data suggest that Sar1 interacts with SVIP and forms a multimer that facilitates the biogenesis of VTV. Interestingly, silencing of SVIP reduced the VTV generation significantly. Conversely, incubation with MA increased the VTV budding, suggesting recruitment of SVIP on ER surface facilitates the VTV budding. We conclude that SVIP recruits Sar1 on ER membrane and makes an intricate COPII coat leading to the formation of a large vesicle, the VTV. Overall, the data presented in this thesis, determines the role of CideB and SVIP in regulating VLDL sorting and VTV biogenesis.
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Date Issued: 2013
Identifier: CFE0005270, ucf:50553
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005270

Title: A THREE-DIMENSIONAL BAY/ESTUARY MODEL TO SIMULATE WATER QUALITY TRANSPORT.
Creator: Yu, Jing, Yeh, Gour-Tsyh, University of Central Florida
Abstract / Description: This thesis presents the development of a numerical water quality model using a general paradigm of reaction-based approaches. In a reaction-based approach, all conceptualized biogeochemical processes are transformed into a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and...
Show moreThis thesis presents the development of a numerical water quality model using a general paradigm of reaction-based approaches. In a reaction-based approach, all conceptualized biogeochemical processes are transformed into a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and erroneous formulation and parameterization of these reactions, and (2) fast reactions and slow reactions are decoupled, which enables robust numerical integrations. The system of species transport equations is transformed to reaction-extent transport equations, which is then approximated with two subsets: algebraic equations and kinetic-variables transport equations. As a result, the model alleviates the needs of using simple partitions for fast reactions. With the diagonalization strategy, it makes the inclusion of arbitrary number of fast and kinetic reactions relatively easy, and, more importantly, it enables the formulation and parameterization of kinetic reactions one by one. To demonstrate the general paradigm, QAUL2E was recasted in the mode of a reaction network. The model then was applied to the Loxahatchee estuary to study its response to a hypothetical biogeochemical loading from its surrounding drainage. Preliminary results indicated that the model can simulate four interacting biogeochemical processes: algae kinetics, nitrogen cycle, phosphorus cycle, and dissolved oxygen balance.
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Date Issued: 2006
Identifier: CFE0001372, ucf:46991
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001372

Title: Implementation Strategies for Real-time Traffic Safety Improvements on Urban Freeways.
Creator: Dilmore, Jeremy, Abdel-Aty, Mohamed, University of Central Florida
Abstract / Description: This research evaluates Intelligent Transportation System (ITS) implementation strategies to improve the safety of a freeway once a potential of a crash is detected. Among these strategies are Variable Speed Limit (VSL) and ramp metering. VSL are ITS devices that are commonly used to calm traffic in an attempt to relieve congestion and enhance throughput. With proper use, VSL can be more cost effective than adding more lanes. In addition to maximizing the capacity of a roadway, a different...
Show moreThis research evaluates Intelligent Transportation System (ITS) implementation strategies to improve the safety of a freeway once a potential of a crash is detected. Among these strategies are Variable Speed Limit (VSL) and ramp metering. VSL are ITS devices that are commonly used to calm traffic in an attempt to relieve congestion and enhance throughput. With proper use, VSL can be more cost effective than adding more lanes. In addition to maximizing the capacity of a roadway, a different aspect of VSL can be realized by the potential of improving traffic safety. Through the use of multiple microscopic traffic simulations, best practices can be determined, and a final recommendation can be made. Ramp metering is a method to control the amount of traffic flow entering from on-ramps to achieve a better efficiency of the freeway. It can also have a potential benefit in improving the safety of the freeway. This thesis pursues the goal of a best-case implementation of VSL. Two loading scenarios, a fully loaded case (90% of ramp maximums) and an off-peak loading case (60% of ramp maximums), at multiple stations with multiple implementation methods are strategically attempted until a best-case implementation is found. The final recommendation for the off-peak loading is a 15 mph speed reduction for 2 miles upstream and a 15 mph increase in speed for the 2 miles downstream of the detector that shows a high crash potential. The speed change is to be implemented in 5 mph increments every 10 minutes. The recommended case is found to reduce relative crash potential from .065 to -.292, as measured by a high-speed crash prediction algorithm (Abdel-Aty et al. 2005). A possibility of crash migration to downstream and upstream locations was observed, however, the safety and efficiency benefits far outweigh the crash migration potential. No final recommendation is made for the use of VSL in the fully loaded case (low-speed case); however, ramp metering indicated a promising potential for safety improvement.
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Date Issued: 2005
Identifier: CFE0000339, ucf:46287
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000339

Title: The Impact of Homelessness and Remaining in School of Origin on the Academic Achievement of Fourth Through Eighth Grade Students in Brevard County Public Schools.
Creator: Dunkel, Richard, Murray, Barbara, Murray, Kenneth, Doherty, Walter, Thedy, Elizabeth, University of Central Florida
Abstract / Description: This study examined the impact of homelessness and the ability of homeless students to remain in their school of origin on the academic achievement of fourth through eighth grade students in Brevard County, Florida. To determine effects of homelessness, homeless students were compared to non-homeless students who qualified for free lunch utilizing developmental scale scores and learning gains from 2011 FCAT Reading and Mathematics. To determine effects of remaining in school of origin,...
Show moreThis study examined the impact of homelessness and the ability of homeless students to remain in their school of origin on the academic achievement of fourth through eighth grade students in Brevard County, Florida. To determine effects of homelessness, homeless students were compared to non-homeless students who qualified for free lunch utilizing developmental scale scores and learning gains from 2011 FCAT Reading and Mathematics. To determine effects of remaining in school of origin, homeless students who changed schools were compared to homeless students who did not change schools utilizing the same assessment data. Independent t-tests and chi-square tests of association were used with .05 significance levels.Findings showed that homeless and non-homeless students had no significant differences in reading scores, and homeless students had significantly higher mathematics scores. However, significantly fewer homeless students made an annual learning gain in reading and math learning gains were statistically equal. Remaining in school of origin also had no significant impact on reading and math developmental scale scores, but a significantly lower percentage of homeless students who changed schools made annual learning gains in reading and mathematics.These results led the researcher to develop a theory called the Weighted Saddle Effect, caused by homeless mobility, to describe the difficulty homeless students had in making annual learning gains commensurate with their developmental scale scores.Recommendations for policy included school districts ensuring transportation to school of origin was available for all homeless students as mandated by the McKinney-Vento Act.
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Date Issued: 2012
Identifier: CFE0004531, ucf:49232
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004531

Title: MASS CONSERVATION ANALYSIS FOR THE LOWER ST. JOHNS RIVER USING CONTINUOUS AND DISCONTINUOUS GALERKIN FINITE ELEMENT METHODS.
Creator: Thomas, Lillie, Hagen, Scott, University of Central Florida
Abstract / Description: This thesis provides a mass conservation analysis of the Lower St. Johns River for the purpose of providing basis for future salinity transport modeling. The analysis provides an assessment of the continuous (CG) and discontinuous (DG) Galerkin finite element methods with respect to their mass conservation properties. The following thesis also presents a rigorous literature review pertaining to salinity transport in the Lower St. Johns River, from which this effort generates the data used to...
Show moreThis thesis provides a mass conservation analysis of the Lower St. Johns River for the purpose of providing basis for future salinity transport modeling. The analysis provides an assessment of the continuous (CG) and discontinuous (DG) Galerkin finite element methods with respect to their mass conservation properties. The following thesis also presents a rigorous literature review pertaining to salinity transport in the Lower St. Johns River, from which this effort generates the data used to initialize and validate numerical simulations. Two research questions are posed and studied in this thesis: can a DG-based modeling approach produce mass conservative numerical solutions; and what are the flow interactions between the river and the marshes within the coastal region of the Lower St. Johns River? Reviewing the available data provides an initial perspective of the ecosystem. For this, salinity data are obtained and assembled for three modeling scenarios. Each scenario, High Extreme, Most Variable, and Low Extreme, is 30 days long (taken from year 1999) and represents a unique salinity regime in the Lower St. Johns River. Time-series of salinity data is collected at four stations in the lower and middle reaches of the Lower St. Johns River, which provides a vantage point for assessing longitudinal variation of salinity. As an aside, precipitation and evaporation data is presented for seven stations along the entire St. Johns River, which provides added insight into salinity transport in the river. A mass conservation analysis is conducted for the Lower St. Johns River. The analysis utilizes a segmentation of the Lower St. Johns River, which divides the domain into sections based on physical characteristics. Mass errors are then calculated for the CG and DG finite element methods to determine mass conservative abilities. Also, the flow interactions (i.e., volume exchange) between the river and marshes are evaluated through the use of tidal prisms. The CG- and DG- finite element methods are then tested in tidal simulation performance, which the results are then compared to observed tides and tidal currents at four stations within the lower portion of the Lower St. Johns River. Since the results show that the DG model outperforms the CG model, the DG model is used in the tidally driven salinity transport simulations. Using four stations within the lower and middle part of the Lower St. Johns River, simulated and observed water levels and salinity concentrations are compared.
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Date Issued: 2011
Identifier: CFE0003736, ucf:48797
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003736

Title: Integrated Sustainability Assessment Framework for the U.S. Transportation.
Creator: Onat, Nuri, Tatari, Omer, Nam, Boo Hyun, Oloufa, Amr, Pazour, Jennifer, University of Central Florida
Abstract / Description: This dissertation aims to investigate the sustainability impacts of alternative vehicle technologies and develop comprehensive sustainability assessment frameworks to analyze potential impacts of these vehicles in the U.S. In order to assess sustainability impact of vehicle alternatives, life-cycle based models has been extensively used in the literature. Although life cycle-based models are often used for environmental impacts of alternative vehicles, analysis of social and economic impacts...
Show moreThis dissertation aims to investigate the sustainability impacts of alternative vehicle technologies and develop comprehensive sustainability assessment frameworks to analyze potential impacts of these vehicles in the U.S. In order to assess sustainability impact of vehicle alternatives, life-cycle based models has been extensively used in the literature. Although life cycle-based models are often used for environmental impacts of alternative vehicles, analysis of social and economic impacts of these vehicles has gained a tremendous interest. In this regard, there is a growing interest among the international platform and academia to use the Life Cycle Sustainability Assessment framework to have more informed sustainable products, material and technology choices by considering the environmental, as well as social and economic impacts. The Life Cycle Sustainability Assessment framework is still under development and there is an ongoing research to advance it for future applications. In this dissertation, current and future needs of sustainability assessment frameworks and the U.S. transportation are identified and addressed. The major research gaps are identified as follows: (1) there has been small emphasis on effects of spatial and temporal variations on the sustainability impacts of alternative vehicle technologies, (2) no national research efforts as of now have been directed specifically toward understanding the fundamental relationship between the adoption of electric vehicles and water demand, (3) there has been a lack of understanding the dynamic complexity of transportation sustainability, encompassing feedback mechanisms, and interdependencies, for the environmental, social, and economic impacts of alternative vehicles, and (4) there is no emphasis on addressing uncertainties inherent to the U.S. transportation and its complex relationships with the environment, society, and economy.The environmental, economic, and social impacts of alternative vehicles are highly critical for truly assessing and understanding the long-term sustainability of vehicles and propose economically viable, socially acceptable, and environmentally-friendly transportation solutions for U.S. passenger transportation. This dissertation provides a more comprehensive sustainability assessment framework by realizing following objectives: (1) inclusion of spatial and temporal variations when quantifying carbon, energy, and water footprints of alternative vehicle technologies, (2) quantifying environmental, social, and economic impacts of alternative vehicle technologies, (3) capturing the dynamic relations among the parameters of U.S. transportation system, environment, society, and the economy, (4) dealing with uncertainties inherent to the U.S. transportation sector considering the complexity of the system and dynamic relationships. The results of this dissertation reveal that the results with consideration of uncertainties, temporal and spatial variations, and dynamic complex relationships among the system variables can be significantly different than those of without consideration of those. Therefore, when developing policies the robustness of proposed scenarios should be valuated with consideration of uncertainties, temporal and spatial variations as well as the dynamic feedback mechanisms. The outcomes of this study can pave the way for advancement in the state-of-the-art and state-of-the-practice in the sustainability research by presenting novel approaches to deal with uncertainties and complex systems.
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Date Issued: 2015
Identifier: CFE0005857, ucf:50904
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005857

Title: Applied Error Related Negativity: Single Electrode Electroencephalography in Complex Visual Stimuli.
Creator: Sawyer, Benjamin, Karwowski, Waldemar, Hancock, Peter, Xanthopoulos, Petros, University of Central Florida
Abstract / Description: Error related negativity (ERN) is a pronounced negative evoked response potential (ERP) that follows a known error. This neural pattern has the potential to communicate user awareness of incorrect actions within milliseconds. While the implications for human-machine interface and augmented cognition are exciting, the ERN has historically been evoked only in the laboratory using complex equipment while presenting simple visual stimuli such as letters and symbols. To effectively harness the...
Show moreError related negativity (ERN) is a pronounced negative evoked response potential (ERP) that follows a known error. This neural pattern has the potential to communicate user awareness of incorrect actions within milliseconds. While the implications for human-machine interface and augmented cognition are exciting, the ERN has historically been evoked only in the laboratory using complex equipment while presenting simple visual stimuli such as letters and symbols. To effectively harness the applied potential of the ERN, detection must be accomplished in complex environments using simple, preferably single-electrode, EEG systems feasible for integration into field and workplace-ready equipment. The present project attempted to use static photographs to evoke and successfully detect the ERN in a complex visual search task: motorcycle conspicuity. Drivers regularly fail to see motorcycles, with tragic results. To reproduce the issue in the lab, static pictures of traffic were presented, either including or not including motorcycles. A standard flanker letter task replicated from a classic ERN study (Gehring et al., 1993) was run alongside, with both studies requiring a binary response. Results showed that the ERN could be clearly detected in both tasks, even when limiting data to a single electrode in the absence of artifact correction. These results support the feasibility of applied ERN detection in complex visual search in static images. Implications and opportunities will be discussed, limitations of the study explained, and future directions explored.
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Date Issued: 2014
Identifier: CFE0005885, ucf:50886
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005885

Title: Electrostatic control over temperature-dependent tunneling across single-molecule junctions.
Creator: Rodriguez Garrigues, Alvar, Del Barco, Enrique, Flitsiyan, Elena, Ishigami, Masa, Hernandez, Eloy, University of Central Florida
Abstract / Description: The aim of the present dissertation is to improve the understanding and methodology of temperature-dependent tunnel conduction through individual molecules by single-electron transport spectroscopy. New advances in electrochemistry present individual molecular diodes as a realistic option for the implementation on molecular circuits thanks to their high current rectification ratios. Therefore, a major requisite in this field is to understand and control the conduction behaviors for a large...
Show moreThe aim of the present dissertation is to improve the understanding and methodology of temperature-dependent tunnel conduction through individual molecules by single-electron transport spectroscopy. New advances in electrochemistry present individual molecular diodes as a realistic option for the implementation on molecular circuits thanks to their high current rectification ratios. Therefore, a major requisite in this field is to understand and control the conduction behaviors for a large variety of conditions. This work focuses on the electric conduction through ferrocene-based molecules as a function of temperatures within a wide range of bias and gate voltages by means of three-terminal electromigrated-broken single-electron transistors (SETs).The results show that the temperature dependence of the current (from 80 to 260 K) depends strongly on the bias and gate voltages, with areas in where the current increases exponentially with temperature (at the Coulomb blockade regimes), and others where the increase of the temperature makes the current only to vary slightly (at resonance) or to decrease monotonically (at the charge degeneracy points). These different observed behaviors of the tunneling current with increasing temperatures can be well explained by a formal single-level coherent tunneling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads. The model portraits the molecule as a localized electrostatic level capacitively coupled to the transistor leads, and the electrical conduction through the junction as coherent sequential tunneling.
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Date Issued: 2016
Identifier: CFE0006171, ucf:51132
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006171

Title: Theoretical Studies of Nanostructure Formation and Transport on Surfaces.
Creator: Aminpour, Maral, Rahman, Talat, Stolbov, Sergey, Roldan Cuenya, Beatriz, Blair, Richard, University of Central Florida
Abstract / Description: This dissertation undertakes theoretical and computational research to characterize and understand in detail atomic configurations and electronic structural properties of surfaces and interfaces at the nano-scale, with particular emphasis on identifying the factors that control atomic-scale diffusion and transport properties. The overarching goal is to outline, with examples, a predictive modeling procedure of stable structures of novel materials that, on the one hand, facilitates a better...
Show moreThis dissertation undertakes theoretical and computational research to characterize and understand in detail atomic configurations and electronic structural properties of surfaces and interfaces at the nano-scale, with particular emphasis on identifying the factors that control atomic-scale diffusion and transport properties. The overarching goal is to outline, with examples, a predictive modeling procedure of stable structures of novel materials that, on the one hand, facilitates a better understanding of experimental results, and on the other hand, provide guidelines for future experimental work. The results of this dissertation are useful in future miniaturization of electronic devices, predicting and engineering functional novel nanostructures. A variety of theoretical and computational tools with different degrees of accuracy is used to study problems in different time and length scales. Interactions between the atoms are derived using both ab-initio methods based on Density Functional Theory (DFT), as well as semi-empirical approaches such as those embodied in the Embedded Atom Method (EAM), depending on the scale of the problem at hand. The energetics for a variety of surface phenomena (adsorption, desorption, diffusion, and reactions) are calculated using either DFT or EAM, as feasible. For simulating dynamic processes such as diffusion of ad-atoms on surfaces with dislocations the Molecular Dynamics (MD) method is applied. To calculate vibrational mode frequencies, the infinitesimal displacement method is employed. The combination of non-equilibrium Green's function (NEGF) and DFT is used to calculate electronic transport properties of molecular devices as well as interfaces and junctions.
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Date Issued: 2013
Identifier: CFE0005298, ucf:50504
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005298

Title: Validation of a novel hypothesis of generating foam cells by its use to study reverse cholesterol transport.
Creator: Sengupta, Bhaswati, Parthasarathy, Sampath, Singla, Dinender, Jewett, Mollie, Rohde, Kyle, University of Central Florida
Abstract / Description: Generation of foam cells, an essential step for reverse cholesterol transport (RCT) studies, uses the technique of receptor dependent macrophage loading with radiolabeled acetylated Low Density Lipoprotein (Ac-LDL). In this study, we used the ability of a biologically relevant detergent molecule, Lysophosphatidylcholine (Lyso PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabelled cholesterol / Lyso PtdCho...
Show moreGeneration of foam cells, an essential step for reverse cholesterol transport (RCT) studies, uses the technique of receptor dependent macrophage loading with radiolabeled acetylated Low Density Lipoprotein (Ac-LDL). In this study, we used the ability of a biologically relevant detergent molecule, Lysophosphatidylcholine (Lyso PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabelled cholesterol / Lyso PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4(&)deg;C and retained the solubilized cholesterol during one month storage. Macrophages incubated with cholesterol or CE (unlabeled, fluorescently labeled or radiolabeled) / Lyso PtdCho mixed micelles accumulated CE as documented by microscopy, lipid staining, labeled oleate incorporation, and by thin layer chromatography (TLC). Such foam cells unloaded cholesterol when incubated with high density lipoprotein (HDL) and not with oxidized HDL (Ox-HDL). We propose that stable cholesterol or CE / Lyso PtdCho micelles would offer advantages over existing methods.Oxidative stress is associated with heart failure (HF). Previously our research group observed that the patients with low left-ventricular ejection fraction showed accumulation of high level of oxidized LDL (Ox-LDL) when compared with the heart failure patients with normal range of ejection fraction (EF). HDL is known to be atheroprotective and one of its important antioxidative functions is to protect LDL from oxidative modifications. However, HDL itself undergoes oxidation and Ox-HDL becomes functionally poor. It is expected to have a diminished ability to promote reverse cholesterol transport. Therefore, it was hypothesized that the quality of HDL present in the patients with EF would more compromised than those present in the patients with normal EF. Functionality of HDL was evaluated by measuring its cholesterol efflux capacity from foam cells generated in vitro. Functionality of HDL, which is strongly related to the oxidative modifications of HDL was further estimated by measuring paraoxonase 1 (PON1) enzyme activity associated with HDL. Higher the PON1 activity and RCT ability, better is the functionality of HDL.
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Date Issued: 2014
Identifier: CFE0005250, ucf:50596
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005250

Title: Fusing Freight Analysis Framework and Transearch Data: An Econometric Data Fusion Approach.
Creator: Momtaz, Salah Uddin, Eluru, Naveen, Abdel-Aty, Mohamed, Anowar, Sabreena, Zheng, Qipeng, University of Central Florida
Abstract / Description: A major hurdle in freight demand modeling has always been the lack of adequate data on freight movements for different industry sectors for planning applications. Freight Analysis Framework (FAF), and Transearch (TS) databases contain annualized commodity flow data. The primary motivation for our study is the development of a fused database from FAF and TS to realize transportation network flows at a fine spatial resolution (county-level) while accommodating for production and consumption...
Show moreA major hurdle in freight demand modeling has always been the lack of adequate data on freight movements for different industry sectors for planning applications. Freight Analysis Framework (FAF), and Transearch (TS) databases contain annualized commodity flow data. The primary motivation for our study is the development of a fused database from FAF and TS to realize transportation network flows at a fine spatial resolution (county-level) while accommodating for production and consumption behavioral trends (provided by TS). Towards this end, we formulate and estimate a joint econometric model framework grounded in maximum likelihood approach to estimate county-level commodity flows. The algorithm is implemented for the commodity flow information from 2012 FAF and 2011 TS databases to generate transportation network flows for 67 counties in Florida. The data fusion process considers several exogenous variables including origin-destination indicator variables, socio-demographic and socio-economic indicators, and transportation infrastructure indicators. Subsequently, the algorithm is implemented to develop freight flows for the Florida region considering inflows and outflows across the US and neighboring countries. The base year models developed are employed to predict future year data for years 2015 through 2040 in 5-year increments at the same spatial level. Furthermore, we disaggregate the county level flows obtained from algorithm to a finer resolution - statewide transportation analysis zone (SWTAZ) defined by the FDOT. The disaggregation process allocates truck-based commodity flows from a 79-zone system to an 8835-zone system. A two-stage factor multiplication method is proposed to disaggregate the county flow to SWTAZ flow. The factors are estimated both at the origin and destination level using a random utility factional split model approach. Eventually, we conducted a sensitivity analysis of the parameterization by evaluating the model structure for different numbers of intermediate stops in a route and/or the number of available routes for the origin-destinations.
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Date Issued: 2018
Identifier: CFE0007763, ucf:52384
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007763

Title: Community Participation and Travel Choice: An Analysis of Central Florida New Urban and Conventional Suburban Residents.
Creator: Mikovsky, Laura, Korosec, Ronnie, Hawkins, Christopher, Knox, Claire, Beitsch, Owen, University of Central Florida
Abstract / Description: Previous research has demonstrated a relationship between the built environment and social and transportation outcomes when comparing traditional and conventional suburban neighborhoods, but much remains to be learned about whether New Urbanism can produce similar results. Among studies where new urban neighborhoods have been assessed, most have centered on regions with highly-utilized public transit systems and with climates that are amenable to utilitarian physical activity. This research...
Show morePrevious research has demonstrated a relationship between the built environment and social and transportation outcomes when comparing traditional and conventional suburban neighborhoods, but much remains to be learned about whether New Urbanism can produce similar results. Among studies where new urban neighborhoods have been assessed, most have centered on regions with highly-utilized public transit systems and with climates that are amenable to utilitarian physical activity. This research sought to build on the existing research base through direct comparison of new urban and conventional suburban neighborhoods in central Florida, a region with an under-developed transit system and a climate that renders utilitarian physical activity impractical. Further, this research sought to lend greater insights into neighborhood selection factors across neighborhood types.(<)p(>)(<)p(>)A mixed-methods, single-case design was utilized to evaluate one new urban and one conventional suburban neighborhood in the central Florida region. Regional new urban neighborhoods were subjectively rated for adherence to tenets of the Charter of the New Urbanism, with the neighborhood (Celebration, in Osceola County, FL) found to most closely adhere to these tenets selected as the experimental group for the study. A socio-demographically comparable conventional suburban neighborhood (Sweetwater, in Seminole County, FL) was selected as the control group. Quantitative methods consisted of a household survey issued to 250 randomly- and convenience-sampled addresses in each neighborhood, followed by regression analysis to evaluate study hypotheses. Qualitative methods employed analysis of open-ended survey responses, detailed case studies of selected neighborhoods, and resident interviews. The household survey yielded net response rates of 15.79 percent and 25.50 percent for experimental and control neighborhoods, respectively, and a mean cross-neighborhood response rate of 20.64 percent. Twenty resident interviews (10 per neighborhood) were conducted. Quantitative and qualitative findings were compared to collectively address research questions.(<)p(>)(<)p(>)Regression results indicated no statistically significant difference between neighborhoods in attitudinal and behavioral components of community participation, in vehicle miles driven per week, or utilitarian physical activity frequency. However, results indicated that new urban residents had more positive attitudes toward utilitarian physical activity than conventional suburban residents and that attitudes toward community participation and utilitarian physical activity were positively correlated with associated behaviors. Qualitative findings provided substantial individual- and environmental-level insights to factors impacting evaluated attitudes and behaviors, and supported some quantitative findings while not aligning with others. Neighborhood selection factors were found to be quite different across neighborhoods: Celebration residents identified neighborhood social atmosphere and connection to the Walt Disney Company brand as top contributors to their selection decision, while Sweetwater residents expressed that access to quality schools was the most important factor in their selection decision. Qualitative findings indicated that car culture and climate within the central Florida region diminished both attitudinal and behavioral components of utilitarian physical activity across neighborhood types.(<)p(>)(<)p(>)This research expanded the understanding of the social and transportation outcomes of New Urbanism, particularly with respect to the central Florida region. While case and quantitative limitations may have impeded the ability of this study to draw decisive conclusions about research questions, distinctive themes regarding social and transportation outcomes were identified. Findings of this research supported those of some prior studies while contradicting others, indicating that further exploration is needed to establish a firm understanding of the capabilities of new urban development to achieve desired outcomes, and of regional characteristics that may influence these outcomes.
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Date Issued: 2012
Identifier: CFE0004413, ucf:49376
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004413

Title: Effects of Signal Probability on Multitasking-Based Distraction in Driving, Cyberattack (&) Battlefield Simulation.
Creator: Sawyer, Benjamin, Karwowski, Waldemar, Hancock, Peter, Xanthopoulos, Petros, University of Central Florida
Abstract / Description: Multitasking-based failures of perception and action are the focus of much research in driving, where they are attributed to distraction. Similar failures occur in contexts where the construct of distraction is little used. Such narrow application was attributed to methodology which cannot precisely account for experimental variables in time and space, limiting distraction's conceptual portability to other contexts. An approach based upon vigilance methodology was forwarded as a solution, and...
Show moreMultitasking-based failures of perception and action are the focus of much research in driving, where they are attributed to distraction. Similar failures occur in contexts where the construct of distraction is little used. Such narrow application was attributed to methodology which cannot precisely account for experimental variables in time and space, limiting distraction's conceptual portability to other contexts. An approach based upon vigilance methodology was forwarded as a solution, and highlighted a fundamental human performance question: Would increasing the signal probability (SP) of a secondary task increase associated performance, as is seen in the prevalence effect associated with vigilance tasks? Would it reduce associated performance, as is seen in driving distraction tasks? A series of experiments weighed these competing assumptions. In the first, a psychophysical task, analysis of accuracy and response data revealed an interaction between the number of concurrent tasks and SP of presented targets. The question was further tested in the applied contexts of driving, cyberattack and battlefield target decision-making. In line with previous prevalence effect inquiry, presentation of stimuli at higher SP led to higher accuracy. In line with existing distraction work, performance of higher numbers of concurrent tasks tended to elicit slower response times. In all experiments raising either number of concurrent tasks or SP of targets resulted in greater subjective workload, as measured by the NASA TLX, even when accompanied by improved accuracy. It would seem that (")distraction(") in previous experiments has been an aggregate effect including both delayed response time and prevalence-based accuracy effects. These findings support the view that superior experimental control of SP reveals nomothetic patterns of performance that allow better understanding and wider application of the distraction construct both within and in diverse contexts beyond driving.
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Date Issued: 2015
Identifier: CFE0006388, ucf:51522
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006388

Title: The effectiveness of Child Restraint and Bicycle Helmet Policies to Improve Road Safety.
Creator: Bustamante, Claudia, Abdel-Aty, Mohamed, Eluru, Naveen, Lee, JaeYoung, University of Central Florida
Abstract / Description: Analyzing the effect of legislation in children's safety when they travel as motor-vehicle passengers and bicycle riders can allow us to evaluate the effectiveness in transportation policies. The Child Restraint Laws (CRL) and Bicycle Helmet Laws (BHL) were studied by analyzing the nationwide Fatality Analysis Reporting System (FARS) to estimate the fatality reduction as well as drivers' decisions to use Child Restraint Systems (CRS) and bicycle helmets respectively. Differences in...
Show moreAnalyzing the effect of legislation in children's safety when they travel as motor-vehicle passengers and bicycle riders can allow us to evaluate the effectiveness in transportation policies. The Child Restraint Laws (CRL) and Bicycle Helmet Laws (BHL) were studied by analyzing the nationwide Fatality Analysis Reporting System (FARS) to estimate the fatality reduction as well as drivers' decisions to use Child Restraint Systems (CRS) and bicycle helmets respectively. Differences in legislation could have different effects on traffic fatalities. Therefore, this study presents multiple methodologies to study these effects. In the evaluation of traffic safety issues, several proven statistical models have shown to be effective at estimating risky factors that might influence crash prevention. These proven models and predictive data analysis guided the process to attempt different models, leading to the development of three specific models used in this study to best estimate the effectiveness of these laws. Then, it was found that legislation in Child Safety Policy has consequences in traffic fatalities. A negative binomial model was created to analyze the CRL influence at the state-level in fatal crashes involving children, and showed that legislating on CRS can reduce the number of fatalities by 29% for children aged 5 to 9. Additionally, at the drivers-level a logistic regression model with random effects was used to determine the significant variables that influence the driver's decision to restrain his/her child. Such variables include: driver's restraint use, road classification, weather condition, number of occupants in the vehicle, traffic violations and driver's and child's age. It was also shown that drivers from communities with deprived socio-economic status are less likely to use CRS. In the same way, a binary logistic regression model was developed to evaluate the effect of BHL in bicycle helmet-use. Findings from this model show that bicyclists from states with the BHL are 236 times more likely to wear a helmet compared to those from states without the BHL. Moreover, the bicyclist's age, gender, education, and income level also influences bicycle helmet use. Both studies suggest that enacting CRL and BHL at the state-level for the studied age groups can be combined with education, safety promotion, enforcement, and program evaluation as proven countermeasures to increase children's traffic safety. This study evidenced that there is a lack of research in this field, especially when policy making requires having enough evidence to support the laws in order to not become an arbitrary legislation procedure affecting child's protection in the transportation system.
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Date Issued: 2017
Identifier: CFE0006571, ucf:51315
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006571

Title: Modeling social norms in real-world agent-based simulations.
Creator: Beheshti, Rahmatollah, Sukthankar, Gita, Boloni, Ladislau, Wu, Annie, Swarup, Samarth, University of Central Florida
Abstract / Description: Studying and simulating social systems including human groups and societies can be a complex problem. In order to build a model that simulates humans' actions, it is necessary to consider the major factors that affect human behavior. Norms are one of these factors: social norms are the customary rules that govern behavior in groups and societies. Norms are everywhere around us, from the way people handshake or bow to the clothes they wear. They play a large role in determining our behaviors....
Show moreStudying and simulating social systems including human groups and societies can be a complex problem. In order to build a model that simulates humans' actions, it is necessary to consider the major factors that affect human behavior. Norms are one of these factors: social norms are the customary rules that govern behavior in groups and societies. Norms are everywhere around us, from the way people handshake or bow to the clothes they wear. They play a large role in determining our behaviors. Studies on norms are much older than the age of computer science, since normative studies have been a classic topic in sociology, psychology, philosophy and law. Various theories have been put forth about the functioning of social norms. Although an extensive amount of research on norms has been performed during the recent years, there remains a significant gap between current models and models that can explain real-world normative behaviors. Most of the existing work on norms focuses on abstract applications, and very few realistic normative simulations of human societies can be found. The contributions of this dissertation include the following: 1) a new hybrid technique based on agent-based modeling and Markov Chain Monte Carlo is introduced. This method is used to prepare a smoking case study for applying normative models. 2) This hybrid technique is described using category theory, which is a mathematical theory focusing on relations rather than objects. 3) The relationship between norm emergence in social networks and the theory of tipping points is studied. 4) A new lightweight normative architecture for studying smoking cessation trends is introduced. This architecture is then extended to a more general normative framework that can be used to model real-world normative behaviors. The final normative architecture considers cognitive and social aspects of norm formation in human societies. Normative architectures based on only one of these two aspects exist in the literature, but a normative architecture that effectively includes both of these two is missing.
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Date Issued: 2015
Identifier: CFE0005577, ucf:50244
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005577

Title: A NEW PARADIGM OF MODELING WATERSHED WATER QUALITY.
Creator: Zhang, Fan, Yeh, Gour-Tsyh, University of Central Florida
Abstract / Description: Accurate models to reliably predict sediment and chemical transport in watershed water systems enhance the ability of environmental scientists, engineers and decision makers to analyze the impact of contamination problems and to evaluate the efficacy of alternative remediation techniques and management strategies prior to incurring expense in the field. This dissertation presents the conceptual and mathematical development of a general numerical model simulating (1) sediment and reactive...
Show moreAccurate models to reliably predict sediment and chemical transport in watershed water systems enhance the ability of environmental scientists, engineers and decision makers to analyze the impact of contamination problems and to evaluate the efficacy of alternative remediation techniques and management strategies prior to incurring expense in the field. This dissertation presents the conceptual and mathematical development of a general numerical model simulating (1) sediment and reactive chemical transport in river/stream networks of watershed systems; (2) sediment and reactive chemical transport in overland shallow water of watershed systems; and (3) reactive chemical transport in three-dimensional subsurface systems. Through the decomposition of the system of species transport equations via Gauss-Jordan column reduction of the reaction network, fast reactions and slow reactions are decoupled, which enables robust numerical integrations. Species reactive transport equations are transformed into two sets: nonlinear algebraic equations representing equilibrium reactions and transport equations of kinetic-variables in terms of kinetically controlled reaction rates. As a result, the model uses kinetic-variables instead of biogeochemical species as primary dependent variables, which reduces the number of transport equations and simplifies reaction terms in these equations. For each time step, we first solve the advective-dispersive transport of kinetic-variables. We then solve the reactive chemical system node by node to yield concentrations of all species. In order to obtain accurate, efficient and robust computations, five numerical options are provided to solve the advective-dispersive transport equations; and three coupling strategies are given to deal with the reactive chemistry. Verification examples are compared with analytical solutions to demonstrate the numerical accuracy of the code and to emphasize the need of implementing various numerical options and coupling strategies to deal with different types of problems for different application circumstances. Validation examples are presented to evaluate the ability of the model to replicate behavior observed in real systems. Hypothetical examples with complex reaction networks are employed to demonstrate the design capability of the model to handle field-scale problems involving both kinetic and equilibrium reactions. The deficiency of current practices in the water quality modeling is discussed and potential improvements over current practices using this model are addressed.
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Date Issued: 2005
Identifier: CFE0000448, ucf:46405
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000448

Title: Microscopic Assessment of Transportation Emissions on Limited Access Highways.
Creator: Abou-Senna, Hatem, Radwan, Ahmed, Abdel-Aty, Mohamed, Al-Deek, Haitham, Cooper, Charles, Johnson, Mark, University of Central Florida
Abstract / Description: On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have...
Show moreOn-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such as VISSIM) with MOVES allows one to obtain precise and accurate emissions estimates. The new United States Environmental Protection Agency (USEPA) mobile source emissions model, MOVES2010a (MOVES) can estimate vehicle emissions on a second-by-second basis creating the opportunity to develop new software (")VIMIS 1.0(") (VISSIM/MOVES Integration Software) to facilitate the integration process. This research presents a microscopic examination of five key transportation parameters (traffic volume, speed, truck percentage, road grade and temperature) on a 10-mile stretch of Interstate 4 (I-4) test bed prototype; an urban limited access highway corridor in Orlando, Florida. The analysis was conducted utilizing VIMIS 1.0 and using an advanced custom design technique; D-Optimality and I-Optimality criteria, to identify active factors and to ensure precision in estimating the regression coefficients as well as the response variable.The analysis of the experiment identified the optimal settings of the key factors and resulted in the development of Micro-TEM (Microscopic Transportation Emissions Meta-Model). The main purpose of Micro-TEM is to serve as a substitute model for predicting transportation emissions on limited access highways to an acceptable degree of accuracy in lieu of running simulations using a traffic model and integrating the results in an emissions model. Furthermore, significant emission rate reductions were observed from the experiment on the modeled corridor especially for speeds between 55 and 60 mph while maintaining up to 80% and 90% of the freeway's capacity. However, vehicle activity characterization in terms of speed was shown to have a significant impact on the emission estimation approach.Four different approaches were further examined to capture the environmental impacts of vehicular operations on the modeled test bed prototype. First, (at the most basic level), emissions were estimated for the entire 10-mile section (")by hand(") using one average traffic volume and average speed. Then, three advanced levels of detail were studied using VISSIM/MOVES to analyze smaller links: average speeds and volumes (AVG), second-by-second link driving schedules (LDS), and second-by-second operating mode distributions (OPMODE). This research analyzed how the various approaches affect predicted emissions of CO, NOx, PM and CO2. The results demonstrated that obtaining accurate and comprehensive operating mode distributions on a second-by-second basis improves emission estimates. Specifically, emission rates were found to be highly sensitive to stop-and-go traffic and the associated driving cycles of acceleration, deceleration, frequent braking/coasting and idling. Using the AVG or LDS approach may overestimate or underestimate emissions, respectively, compared to an operating mode distribution approach.Additionally, model applications and mitigation scenarios were examined on the modeled corridor to evaluate the environmental impacts in terms of vehicular emissions and at the same time validate the developed model (")Micro-TEM("). Mitigation scenarios included the future implementation of managed lanes (ML) along with the general use lanes (GUL) on the I-4 corridor, the currently implemented variable speed limits (VSL) scenario as well as a hypothetical restricted truck lane (RTL) scenario. Results of the mitigation scenarios showed an overall speed improvement on the corridor which resulted in overall reduction in emissions and emission rates when compared to the existing condition (EX) scenario and specifically on link by link basis for the RTL scenario.The proposed emission rate estimation process also can be extended to gridded emissions for ozone modeling, or to localized air quality dispersion modeling, where temporal and spatial resolution of emissions is essential to predict the concentration of pollutants near roadways.
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Date Issued: 2012
Identifier: CFE0004777, ucf:49788
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004777

Title: Shock Tube Investigations of Novel Combustion Environments Towards a Carbon-Neutral Future.
Creator: Barak, Samuel, Vasu Sumathi, Subith, Kapat, Jayanta, Ahmed, Kareem, University of Central Florida
Abstract / Description: Supercritical carbon dioxide (sCO2) cycles are being investigated for the future of power generation. These cycles will contribute to a carbon-neutral future to combat the effects of climate change. These direct-fired closed cycles will produce power without adding significant pollutants to the atmosphere. For these cycles to be efficient, they will need to operate at significantly higher pressures (e.g., 300 atm for Allam Cycle) than existing systems (typically less than 40 atm). There is...
Show moreSupercritical carbon dioxide (sCO2) cycles are being investigated for the future of power generation. These cycles will contribute to a carbon-neutral future to combat the effects of climate change. These direct-fired closed cycles will produce power without adding significant pollutants to the atmosphere. For these cycles to be efficient, they will need to operate at significantly higher pressures (e.g., 300 atm for Allam Cycle) than existing systems (typically less than 40 atm). There is limited knowledge on combustion at these pressures or at the high dilution of carbon dioxide. Nominal fuel choices for gas turbines include natural gas and syngas (mixture of CO and H2). Shock tubes study these problems in order to understand the fundamentals and solve various challenges. Shock tube experiments have been studied by the author in the sCO2 regime for various fuels including natural gas, methane and syngas. Using the shock tube to take measurements, pressure and light emissions time-histories measurements were taken at a 2-cm axial location away from the end wall. Experiments for syngas at lower pressure utilized high-speed imaging through the end wall to investigate the effects of bifurcation. It was found that carbon dioxide created unique interactions with the shock tube compared to tradition bath gasses such as argon. The experimental results were compared to predictions from leading chemical kinetic mechanisms. In general, mechanisms can predict the experimental data for methane and other hydrocarbon fuels; however, the models overpredict for syngas mixtures. Reaction pathway analysis was evaluated to determine where the models need improvements. A new shock tube has been designed and built to operate up to 1000 atm pressures for future high-pressure experiments. Details of this new facility are included in this work. The experiments in this work are necessary for mechanism development to design an efficient combustor operate these cycles.
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Date Issued: 2019
Identifier: CFE0007781, ucf:52359
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007781

Title: Alpha-Tocopherol Reduces VLDL Secretion Through Modulation of the VLDL Transport Vesicle.
Creator: Clay, Ryan, Siddiqi, Shadab, Altomare, Deborah, Masternak, Michal, University of Central Florida
Abstract / Description: The liver distributes serum triacylglycerol (TAG) via the very low-density lipoprotein (VLDL), and an increase in VLDL production may result in hyperlipidemia. VLDL synthesis consists of lipidation of Apolipoprotein B100 (ApoB) as it is co- translationally translocated across the endoplasmic reticulum (ER) membrane, and this nascent VLDL particle must undergo subsequent maturation and post-translational modification in the Golgi. The ER-to-Golgi trafficking of VLDL represents the rate...
Show moreThe liver distributes serum triacylglycerol (TAG) via the very low-density lipoprotein (VLDL), and an increase in VLDL production may result in hyperlipidemia. VLDL synthesis consists of lipidation of Apolipoprotein B100 (ApoB) as it is co- translationally translocated across the endoplasmic reticulum (ER) membrane, and this nascent VLDL particle must undergo subsequent maturation and post-translational modification in the Golgi. The ER-to-Golgi trafficking of VLDL represents the rate-limiting step in VLDL secretion and is mediated by the VLDL Transport Vesicle (VTV). Many in vivo studies have indicated that vitamin E (alpha-tocopherol) supplementation protects against atherosclerosis and can reduce hepatic steatosis in nonalcoholic fatty liver disease (NAFLD), but its effects at the molecular level on hepatic lipid metabolism are poorly understood. To investigate the effects of alpha-tocopherol on hepatic VLDL secretion and cellular lipid retention, we performed several experiments in HepG2 (human) and McARH- 7777 (rat) hepatoma cell lines including pulse-chase experiments using 3H-oleic acid (3H- OA), confocal microscopy with BODIPY lipid droplet staining, and an in vitro VTV budding assay. Our results demonstrate a significant reduction of 3H-TAG secretion and ApoB media expression in response to 100 uM alpha-tocopherol, with a corresponding decrease in markers of VTV biogenesis in western blots of whole cell lysates (WCL) and retention of ApoB within the cell, indicating disruption of an early step in VLDL biogenesis. Further evidence indicates an increase in size and lipidation of the VTV and VLDL particle. BODIPY staining as well as 3H-TAG retention in WCLs was also sharply reduced. Overall, these results indicate that alpha-tocopherol reduces VLDL secretion, partially disrupts hepatic VLDL synthesis and VTV biogenesis, increases the lipidation of remaining VLDL particles, and diminishes overall cellular lipid droplet retention.
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Date Issued: 2019
Identifier: CFE0007617, ucf:52538
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007617

Title: Multi-Level Safety Performance Functions for High Speed Facilities.
Creator: Ahmed, Mohamed, Abdel-Aty, Mohamed, Radwan, Ahmed, Al-Deek, Haitham, Mackie, Kevin, Pande, Anurag, Uddin, Nizam, University of Central Florida
Abstract / Description: High speed facilities are considered the backbone of any successful transportation system; Interstates, freeways, and expressways carry the majority of daily trips on the transportation network. Although these types of roads are relatively considered the safest among other types of roads, they still experience many crashes, many of which are severe, which not only affect human lives but also can have tremendous economical and social impacts. These facts signify the necessity of enhancing the...
Show moreHigh speed facilities are considered the backbone of any successful transportation system; Interstates, freeways, and expressways carry the majority of daily trips on the transportation network. Although these types of roads are relatively considered the safest among other types of roads, they still experience many crashes, many of which are severe, which not only affect human lives but also can have tremendous economical and social impacts. These facts signify the necessity of enhancing the safety of these high speed facilities to ensure better and efficient operation. Safety problems could be assessed through several approaches that can help in mitigating the crash risk on long and short term basis. Therefore, the main focus of the research in this dissertation is to provide a framework of risk assessment to promote safety and enhance mobility on freeways and expressways. Multi-level Safety Performance Functions (SPFs) were developed at the aggregate level using historical crash data and the corresponding exposure and risk factors to identify and rank sites with promise (hot-spots). Additionally, SPFs were developed at the disaggregate level utilizing real-time weather data collected from meteorological stations located at the freeway section as well as traffic flow parameters collected from different detection systems such as Automatic Vehicle Identification (AVI) and Remote Traffic Microwave Sensors (RTMS). These disaggregate SPFs can identify real-time risks due to turbulent traffic conditions and their interactions with other risk factors.In this study, two main datasets were obtained from two different regions. Those datasets comprise historical crash data, roadway geometrical characteristics, aggregate weather and traffic parameters as well as real-time weather and traffic data.At the aggregate level, Bayesian hierarchical models with spatial and random effects were compared to Poisson models to examine the safety effects of roadway geometrics on crash occurrence along freeway sections that feature mountainous terrain and adverse weather. At the disaggregate level; a main framework of a proactive safety management system using traffic data collected from AVI and RTMS, real-time weather and geometrical characteristics was provided. Different statistical techniques were implemented. These techniques ranged from classical frequentist classification approaches to explain the relationship between an event (crash) occurring at a given time and a set of risk factors in real time to other more advanced models. Bayesian statistics with updating approach to update beliefs about the behavior of the parameter with prior knowledge in order to achieve more reliable estimation was implemented. Also a relatively recent and promising Machine Learning technique (Stochastic Gradient Boosting) was utilized to calibrate several models utilizing different datasets collected from mixed detection systems as well as real-time meteorological stations. The results from this study suggest that both levels of analyses are important, the aggregate level helps in providing good understanding of different safety problems, and developing policies and countermeasures to reduce the number of crashes in total. At the disaggregate level, real-time safety functions help toward more proactive traffic management system that will not only enhance the performance of the high speed facilities and the whole traffic network but also provide safer mobility for people and goods. In general, the proposed multi-level analyses are useful in providing roadway authorities with detailed information on where countermeasures must be implemented and when resources should be devoted. The study also proves that traffic data collected from different detection systems could be a useful asset that should be utilized appropriately not only to alleviate traffic congestion but also to mitigate increased safety risks. The overall proposed framework can maximize the benefit of the existing archived data for freeway authorities as well as for road users.
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Date Issued: 2012
Identifier: CFE0004508, ucf:49274
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004508

Intelligent Transportation Systems (7)	+ -
transportation (7)	+ -
electron transport (5)	+ -
VLDL (4)	+ -
Sustainable Transportation (3)	+ -

Transportation (3)	+ -
VTV (3)	+ -
Variable Speed Limits (3)	+ -
graphene (3)	+ -
transport (3)	+ -
ApoB (2)	+ -
Charge Transport (2)	+ -
Cholesterol (2)	+ -
Fast/ Equilibrium Reactions (2)	+ -
Finite Element Method (2)	+ -
Fully-implicit (2)	+ -
Kinetic-Variable (2)	+ -
Lagrangian-Eulerian approach (2)	+ -
Life Cycle Sustainability Assessment (2)	+ -
Modeling (2)	+ -
Operator-splitting (2)	+ -
Polyamines (2)	+ -
Predictor-corrector (2)	+ -
Reactive Chemical Transport (2)	+ -
SVIP (2)	+ -
Safety (2)	+ -
Slow/Kinetic Reactions (2)	+ -
System Dynamics (2)	+ -
Traffic Simulation (2)	+ -
Transportation Engineering (2)	+ -

ETD Collection (78)	+ -
Honors Collection (7)	+ -

University of Central Florida (84)	+ -
Abdel-Aty, Mohamed (12)	+ -
Eluru, Naveen (6)	+ -
Al-Deek, Haitham (5)	+ -
Khondaker, Saiful (5)	+ -

Oloufa, Amr (5)	+ -
Radwan, Ahmed (5)	+ -
Siddiqi, Shadab (5)	+ -
Uddin, Nizam (5)	+ -
Xanthopoulos, Petros (5)	+ -
Del Barco, Enrique (4)	+ -
Leuenberger, Michael (4)	+ -
Naser, Saleh (4)	+ -
Radwan, Essam (4)	+ -
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