This thesis conducted research on the impact of campaign visits on levels of predicted voter choice within the 2016 U.S. Presidential election. Data on discrete events throughout the campaign were collected to first determine the impact of particular newsworthy events on predicted voter choice. The data show that the impact of these events dissipates prior to Election Day, leading to a minimal impact on voter decision making. Additionally, data were analyzed on the occurrence of both candidate and surrogate visits, attempting to add to the field of research regarding the impact of campaign visits on voters. Throughout the analysis, both safe and swing states were taken into consideration, to determine if campaigns have a similar impact in different types of states. Overall, fourteen individual states were examined, providing a rather small sample size, but focusing on where campaigns were concentrated most. The results showed that the minimal effects hypothesis is still mostly affirmed, but that candidate visits appear to have a greater influence on predicted voter choice than do surrogate visits, regardless of the popularity of the surrogate. / Master of Arts / This thesis conducted research on the impact that candidate visits had on voters. The research focused on the 2016 U.S. Presidential election. In addition to focusing on the role of campaign visits, eight specific events from the campaign were selected to attempt to determine the impact that newsworthy events had on voters. The data show that the impact of these events is not lasting and does not appear to have an impact on the outcome of the election. Additionally, visits by both candidates and surrogates (those visiting on behalf of a candidate) were analyzed in order to determine whether these visits led to a change in voter choice. Throughout the analysis, states favoring one candidate as well as divided or swing states were taken into consideration to determine if campaigns impacted voters in different states in different ways. Overall, fourteen individual states were examined, providing a rather small sample size, but focusing on where campaigning was concentrated most. The results showed that candidate visits have very little impact on whom voters ultimately choose, but that candidate visits appear to have a greater influence on this than do surrogate visits, regardless of the popularity of the surrogate.

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The objective of this study was to identify critical parameters of application for selected harvest and fabrication intervention strategies used to control Escherichia coli O157:H7 and Salmonella. Paired, boneless, beef strip loin (n=120, IMPS 180) were selected at a commercial cow harvest facility, transported to the Food Microbiology Laboratory, Texas A&M University, and inoculated with nonpathogenic, rifampicin-resistant E. coli organisms (ATCC #1427, 1428, 1430) to simulate harvest floor contamination. The beef strip loins were inoculated hot (~30°C) and then subjected to one of three chemical treatments (L-lactic acid, peroxyacetic acid, and acidified sodium chlorite) including subset variations for concentration and pH. Lactic acid was applied warm (~53°C) and at room temperature (~25°C), whereas the peroxyacetic acid, and acidified sodium chlorite were applied at room temperature (~25°C). Lactic acid was applied at concentrations of 2.5% and 5% using different water sources (tap and distilled), and at a common pH of ~2.2 using different water sources (tap and distilled). Peroxyacetic acid was applied at concentrations of 210 ppm and 150 ppm, and acidified sodium chlorite was applied at concentrations of 500 ppm and 1200 ppm. Half of the strip loins received the chemical interventions prior to chilling or “hot” (~25°C), whereas the other half received the interventions after a chilling for ~24 h at ~2°C. When applied to hot strip loins, only the 2.5% and 5% lactic acid treatments resulted in a greater than 1 log reduction, but for chilled strip loins all treatments achieved greater than a 1 log reduction. When tap water was used to prepare the intervention, there was a difference between reductions for hot (0.68 CFU/cm2) and chilled (2.02 CFU/cm2) product, but there were no differences between hot and chilled for distilled water. Also, there were no differences in reductions between using tap and distilled water for hot products or for chilled products. The pH of the meat surface was lowest for the 5.0% lactic acid (3.07) and highest for the 150 ppm peroxyacetic acid (6.07). These data support the significance of conducting in-plant validation studies utilizing the specific parameters used in the plant.

Speakers of American Sign Language use surrogates and tokens throughout their discourse. Surrogates allow signers to shift roles (or perspectives) and “become” a character or other entity in their discourse. Tokens allow them to miniaturize entities and bring them into a smaller signing space. Scott Liddell claims that surrogates and tokens cannot interact or converse with one another. He states that because surrogates are in the “here and now” and tokens are not, they are unable to interact with each other. He also claims that surrogates and tokens are unable to enter each other’s signing spaces. In this research project, I explore examples that show otherwise. I have found examples where surrogates and tokens would be able to converse with one another, should the need arise. I have also found examples of tokens entering surrogate space, giving them the “here and now” feature Liddell says they do not possess. / May 2016

A suite of tools to reduce the computational effort in groundwater modeling validation and testing has been developed. The work herein explores reduction of computational effort via smart adaptivemeshing, optimization techniques, which require fewer model calls, and the development of surrogate models. Adaptive meshing reduces the computational domain by allowing for mesh refinement in areas of interest determined dynamically by the model through error indicators instead of requiring a priori knowledge or a posteriori determination and rebuilding of the computational domain. As the areas of interest change with the physics, the refinement is removed to lower computational time by using unrefinement. The computational time for dynamic mesh adaption versus uniform refinement is orders of magnitudes smaller. Further reduction in computational time may be required especially when using parameter estimation techniques that require on the order of 2n computations, where n is the number of parameters being estimated. A demonstration of the usefulness of parameter estimation techniques is given, followed by a discussion of methods to further reduce computational time. It may also be necessary to look at reduced physics-type methods to further reduce computational time for the physics-based model. Surrogate models, such as proper orthogonal decomposition (POD), greatly reduce the computational time while maintaining the most important aspects of the physics being solved. The idea here is to run the full model, create the PODs basis, then use this basis to run parameter estimation. Once a better fit has been determined, the full model is run again to capture the full-physics results. The technique is repeated as necessary to capture the “best” parameters to numerically represent the observed behavior.

Nanoparticles (NPs) have attracted considerable attention in the field of separation science, especially in filtration studies for direct membrane integrity tests, investigating pore-size distribution, and their potential to be used as surrogates for various types of viruses encountered in water treatment and bioprocessing applications. Although the effect of adding surfactants to stabilize NP suspension have been explored for a number of different applications, there is significant variation in the amounts and types of surfactants used in filtration studies. This study used three different sizes (59, 188, and 490 nm) of fluorescent polystyrene nanoparticles (PNPs) to mimic the length, width, and aggregates of Rhabdovirus Maraba, a bullet-shape envelope virus. The PNPs were suspended in solutions with varying concentrations of the nonionic surfactant Tween 20 (0.0005% to 0.1% (v/v) in the carbonate buffer feed solution) and were tested in constant-flux filtration studies using two commercial microfiltration (MF) membranes (Durapore PVDF and MiniSart PES) with 0.22 micron pore size ratings. Results clearly demonstrate that adding a nonionic surfactant to a PNP solution will cause a shift from full retention to complete transmission during the dead-end MF of PNPs that are smaller than the pore size of an MF membrane. In a separate study, in order to have a better resemblance of virus particles in terms of surface properties, 188 nm PNPs were coated with different (lysozyme, α -lactalbumin and bovine serum albumin) proteins in order to gain similar surface properties to actual virus particles. Filtration results with one type of commercial MF membranes (Durapore PVDF) 0.22 μm pore size, clearly indicate that the transmission behavior of PNPs strongly depends on their surface properties. PNPs fully covered with BSA and α–lactalbumin could completely pass through the membranes while uncovered or partially covered PNPs resulted in no transmission or partial transmission. / Thesis / Master of Applied Science (MASc) / Nanoparticles (NPs) has been employed enormously in various applications for a variety of purposes. One of the areas that have been greatly influenced by NPs, is the field of separation science. In the pharmaceutical industry, purification of therapeutics involves a sequence of filtration and in this step, therapeutic virus filtration, sterile filtration, in particular, have been poorly studied. There is also a growing interest in the use of engineered viruses for cancer treatment due to its magnificent implication on human health. However, there are significant challenges in running filtration experiments with pathogenic substances. Therefore it has been determined that a detailed and comprehensive study of sterile filtration of virus-size NPs can benefit this area. In this work, fluorescently-labeled NPs has been used as surrogates of oncolytic viruses to extract fundamental aspects affecting the transmission of virus-sized particles through commercial microfiltration sterilizing grade membranes.

Antimicrobial interventions implemented in slaughter establishments for the reduction of enteric pathogens on beef carcasses must be validated to demonstrate efficacy under commercial operation conditions. Validation studies can be conducted using surrogates which are nonpathogenic organisms that respond to a particular treatment in a manner equivalent to a target pathogen. The purpose of this study was to identify surrogates for enteric pathogens to validate antimicrobial interventions on beef carcasses. The growth, attachment, resistance properties as well as the response to interventions on beef carcasses of nonpathogenic fluorescent protein-marked E. coli strains were evaluated and compared to E. coli O157:H7 and Salmonella strains. Growth curves were performed in tryptic soy broth at 37°C and it was demonstrated that in general, growth parameters were not different among surrogates and target pathogens. Thermal resistance was compared in phosphate buffered saline (PBS) at 55, 60 and 65°C; D-values of surrogates were not different or were higher than those of target pathogens. The acid resistance of surrogates was not different to that of E. coli O157:H7 in PBS acidified with lactic acid at pH 2.5, 3.0 and 3.5. Some Salmonella serotypes were found to be less acid resistant than the surrogates. Survival of surrogates after storage at low temperatures (4°C and -18°C) was not different or was longer than survival of E. coli O157:H7 and Salmonella. Additionally, the cell surface hydrophobicity and attachment to beef carcasses surfaces was not different among surrogates and pathogens. Antimicrobial interventions were applied on carcass surfaces under laboratory controlled conditions. After application of hot water washes, D-values were not different among surrogates and pathogens, while no differences were observed in log reductions (CFU/cm2) among surrogates and pathogens when 2% L-lactic acid sprays at 25 and 55°C were applied, regardless of the temperature and volume of the acid solution. The response of surrogates to water washes and lactic acid sprays on beef carcasses was also evaluated in commercial slaughter facilities. Reductions of surrogates were not different to those of aerobic plate count, coliforms and E. coli. However, the surrogates showed less variation and provided more consistent results than traditional indicators.

The killing effectiveness of electron beam irradiation has not been completely characterized. The type of microorganisms and the composition of food have a direct effect on the efficiency of this technology. The objectives of this study were to select a surrogate suitable for use in electron beam irradiation studies of fruits and to evaluate the effect of sugar content on the kinetics of microbial damage and recovery. A 2.0 MeV Van de Graaff linear accelerator was used to apply irradiation (up to 5.0 kGy), using different configurations, on gelatin-based systems with the addition of sugars. The systems were inoculated with pathogenic and non-pathogenic bacteria strains (surrogates). Initial studies showed that Escherichia coli K-12 MG1655 is a suitable surrogate that represents the damage induced to common fruit pathogens by irradiation. The reduction in bacteria population can be maintained by storing samples at 4°C. An increase in temperature up to 20°C was enough for the damaged population to recover in 48 hours. Gelatin-based systems proved to be a simple and inexpensive medium to evaluate the effects of irradiation (up to 5.0 kGy) on selected bacteria. Reduction of the system dimensions and their positioning related to the beam source were key factors in increasing the killing effectiveness of irradiation. The sugar levels (up to 8 %) used to mimic the maturity of cantaloupes had no effect on the radiation D10 values and the recovery of the surrogate population quantified as Generation Times. The resistance of the surrogate to irradiation was validated in an optimum configuration and in cantaloupes. Temperature and sugar content caused significantly higher changes to the physical structure of the gel-based systems than irradiation (1.0 kGy). Plate counts and light microscopy techniques demonstrated that the structure of the gelatin-based systems allow for motility of the bacteria in a 3-D array (length, width and depth). When little information was available about the effectiveness of using a low energy linear accelerator, the inoculation of gelatin-based systems proved to be a reliable method to select a suitable surrogate and to predict the effects of irradiation on bacteria as a function of sugar content.

A better understanding and control of internal combustion engine pollutants require more insightful investigation of gasoline oxidation chemistry. An oxidation study has been done on n-heptane, iso-octane, their binary mixtures (Primary Reference Fuel, (PRF)), and nine hydrocarbon mixtures which represent the second generation of gasoline surrogates (multi-component surrogates). This study aims to develop a better understanding of the combustion reaction by studying the oxidation reaction of different fuels inside a jet-stirred reactor and numerically simulating the reaction using different models under the following conditions: pressure 1 bar, temperature 500-1050K, residence time 1.0 and 2.0s, and two fuel-to-oxygen ratios (ϕ=0.5 and 1.0). Intermediate and product species mole fractions versus temperature profiles were experimentally measured using a GC (gas chromatograph). The experiment was performed within the high and low-temperature regions, where the high-temperature oxidation showed similar behavior for different compositions but the low-temperature oxidation showed significant dependence on the composition of the surrogates. Additionally, the effect of octane number on oxidation chemistry has been investigated and it was found that the low octane number surrogates were more reactive than high octane number surrogates during the low temperature regime. Furthermore, Kinetic analysis was conducted to provide insightful understanding of different factors of fuel reactivity. In addition, the pyrolysis of two TPRF, (Toluene primary reference fuels) mixtures (TPRF70 and TPRF97.5), representing low octane (research octane number 70) and high octane (research octane number 97.5) gasoline, was also studied in jet-stirred reactor coupled with gas chromatography (GC) analysis to investigate the formation of soot and polycyclic aromatic hydrocarbons (PAH) formation.

In der vorliegenden Arbeit wird die Wiederkehr im Phasenraum ausgenutzt. Dabei werden drei Hauptresultate besprochen. 1. Die Wiederkehr erlaubt die Vorhersagbarkeit des Systems zu quantifizieren. 2. Die Wiederkehr enthaelt (unter bestimmten Voraussetzungen) sämtliche relevante Information über die Dynamik im Phasenraum 3. Die Wiederkehr erlaubt die Erzeugung dynamischer Ersatzdaten. / Recurrence plots, a rather promising tool of data analysis, have been introduced by Eckman et al. in 1987. They visualise recurrences in phase space and give an overview about the system's dynamics. Two features have made the method rather popular. Firstly they are rather simple to compute and secondly they are putatively easy to interpret. However, the straightforward interpretation of recurrence plots for some systems yields rather surprising results. For example indications of low dimensional chaos have been reported for stock marked data, based on recurrence plots. In this work we exploit recurrences or ``naturally occurring analogues'' as they were termed by E. Lorenz, to obtain three key results. One of which is that the most striking structures which are found in recurrence plots are hinged to the correlation entropy and the correlation dimension of the underlying system. Even though an eventual embedding changes the structures in recurrence plots considerably these dynamical invariants can be estimated independently of the special parameters used for the computation. The second key result is that the attractor can be reconstructed from the recurrence plot. This means that it contains all topological information of the system under question in the limit of long time series. The graphical representation of the recurrences can also help to develop new algorithms and exploit specific structures. This feature has helped to obtain the third key result of this study. Based on recurrences to points which have the same ``recurrence structure'', it is possible to generate surrogates of the system which capture all relevant dynamical characteristics, such as entropies, dimensions and characteristic frequencies of the system. These so generated surrogates are shadowed by a trajectory of the system which starts at different initial conditions than the time series in question. They can be used then to test for complex synchronisation.