Barrett, The Honors College Thesis/Creative Project Collection

Heliobacteria are an anaerobic phototroph that require carbon sources such as pyruvate, <br/>lactate, or acetate for growth (Sattley, et. al. 2008). They are known for having one of the <br/>simplest phototrophic systems, the central component of which is a Type I reaction center (RC) <br/>that pumps protons to generate the electrochemical gradient for making ATP. Heliobacteria <br/>preform cyclic electron flow (CEF) with the RC in the light but can also grow chemotropically in <br/>the dark. Many anaerobes like heliobacteria, such as other members of the class Clostridia, <br/>possess the capability to produce hydrogen via a hydrogenase enzyme in the cell, as protons can <br/>serve as an electron acceptor in anaerobic metabolism. However, the species of heliobacteria <br/>studied here, H. modesticaldum have been seen to produce hydrogen via their nitrogenase <br/>enzyme but not when this enzyme is inactive. This study aimed to investigate if the reason for <br/>their lack of hydrogen production was due to a lack of an active hydrogenase enzyme, possibly <br/>indicating that the genes required for activity were lost by an H. modesticaldum ancestor. This <br/>was done by introducing genes encoding a clostridial [FeFe] hydrogenase from C. thermocellum<br/>via conjugation and measuring hydrogen production in the transformant cells. Transformant cells <br/>produced hydrogen and cells without the genes did not, meaning that the heliobacteria ferredoxin <br/>was capable of donating electrons to the foreign hydrogenase to make hydrogen. Because the <br/>[FeFe] hydrogenase must receive electrons from the cytosolic ferredoxin, it was hypothesized <br/>that hydrogen production in heliobacteria could be used to probe the redox state of the ferredoxin <br/>pool in conditions of varying electron availability. Results of this study showed that hydrogen <br/>production was affected by electron availability variations due to varying pyruvate <br/>concentrations in the media, light vs dark environment, use acetate as a carbon source, and being <br/>provided external electron donors. Hydrogen production, therefore, was predicted to be an <br/>effective indicator of electron availability in the reduced ferredoxin pool.

This paper will cover a variety of stable isotope systems, both light and heavy, that are used to interpret isotopic analysis in two different disciplines: bioarchaeology and forensic anthropology. To begin, I will give short histories of both bioarchaeology and forensic anthropology, including what is considered to be the beginning of the disciplines as well as the founders of said disciplines. Following the histories of the disciplines, there will be a short background in isotopes and isotopic analysis, including an introduction to isoscapes and how isotopic data can be collected for further interpretation. There will then be an introduction to light isotopes, focusing on the ones used for this thesis, which will lead into the background of each light isotope. Following the light isotopes is an introduction to the heavy isotopes and the backgrounds of each of the heavy isotopes. Finally, this thesis will end in the conclusions section.

Water heaters that are manufactured for swimming pools come in several forms, most of which require an electrical input for a source of power. Passive-circulation systems, however, require no electrical power input because fluid circulation occurs as a result of thermal gradients. In solar-based systems, thermal gradients are developed by energy collected from sunlight. The combination of solar collection and passive circulation yields a system in which fluids, particularly water, are heated and circulated without need of assistance from external mechanical or electrical sources. The design of such a system was adapted from that of forced-circulation solar collector systems, as were the equations describing its thermodynamic properties. The design was developed based on such constraints as material corrosion resistance, overall system cost, and location-controlled size limitations. The thermodynamic description of the designed system was adjusted on the basis of the designed system’s physical aspects, such as the configuration and material of each component within the solar collector. Numerical analysis performed with the altered thermodynamic equations projected a total energy gain of 7.39 W between 9:00 and 10:00 A.M. and a total energy gain of 13.12 W between 4:00 and 5:00 P.M. The temperature of heated water exiting the collector system was projected to be 17.62°C in the morning and 25.56°C in the afternoon. The morning projection utilized an initial fluid temperature of 12°C and an ambient air temperature of 13°C, while the afternoon projection utilized an initial fluid temperature of 17°C and an ambient air temperature of 22°C. Field testing of the designed passive thermosyphon solar collector system was performed over a period of about one month with one temperature measurement taken at the collector outlet in the morning and another taken in the afternoon. For an ambient air temperature of 13°C, the linear regression developed from the morning dataset yielded an outlet water temperature of 20°C and that for the afternoon dataset yielded an outlet water temperature of 39°C for an ambient air temperature of 17°C. The percentage error between the projected and measured results was 13.51% for the morning period and 52.58% for the afternoon period. Numerical simulation and field data demonstrated that while the collector system operated successfully, its effects were limited to the volume of water immediately surrounding the outlet of the system; the rate of circulation within the system was too low for there to be a meaningful increase in the temperature of the water body at large. The stated results demonstrate that while the particular configuration of passive circulation solar collection technology developed in this instance is capable of transferring solar thermal energy to water without additional energy sources, significant modifications are necessary in order to improve the effectiveness of the technology. Such changes may come from improvements in material availability or alterations to the configuration of components of the collector system.

The current study examines the effects that college students' personal characteristics, such as age, sex, gender, or race/ethnicity, have on students’ perceptions of perceived victim blameworthiness. This study also examines how college students’ perceptions of blameworthiness change after being exposed to real life sexual assault vignettes that tap into issues surrounding rape myths. Specifically, I assess blameworthiness perceptions surrounding rape myths regarding clothing, drinking, and various situational characteristics. Blameworthiness perceptions were examined through a survey with pre-test and post-test questions that occurred before and after the student reviewed different sexual assault vignettes. Descriptive statistics show that the majority of college students, after being introduced to the vignettes, reduced their blameworthiness beliefs. Results from the regression analysis show that few individual characteristics are associated with changes in blameworthiness beliefs. Overall, these findings suggest that exposure to sexual assault vignettes have an effect on how individuals perceive victim blameworthiness.

Humans use emotions to communicate social cues to our peers on a daily basis. Are we able to identify context from facial expressions and match them to specific scenarios? This experiment found that people can effectively distinguish negative and positive emotions from each other from a short description. However, further research is needed to find out whether humans can learn to perceive emotions only from contextual explanations.

Police use of force is a controversial practice on both the political stage and by scholars of criminal justice. Scholarly research has highlighted best practice for police departments’ use of force policies. Diverging from these policies may produce ineffective and harmful use of force practices within departments. Because of these potential consequences of police departments diverging from research-based evidence, it is necessary to identify when recommended policy is not being utilized. The purpose of this study is to identify whether there are points of dissent or congruence between criminal justice scholars and police departments with regards to use of force policy. Efforts have been made to empirically identify best practices of use of force policy. The findings of this study indicate that points of dissent do exist in the policies of police departments in the U.S. and the policy recommendations of criminal justice scholars. The implications of these findings include reform to the use of force policies of police departments to more accurately reflect the policies recommended by scholars in the use of force.

Water quality and accessibility can impact most aspects of life such as hygiene, medicine, thermal comfort, sewage disposal, and health, to name a few. Rising concerns related to the quality of drinking water in the United States caused by municipal water utility failures such as in Texas or in Michigan has led to an inquiry into the root cause of how a supply-chain for a basic necessity such as water can run into issues. After initial research and investigation, one hypothesis for this was the nature of how recyclable materials in a linear economy eventually run into production or storage problems as exhaustible resources (or space) become less accessible over time. To remedy this issue, LifeGear360 is introduced to allow individual users the liberty to treat their water directly if needed, while also remaining in a circular economy for the lifecycle of the product. As a backpack with water treatment capabilities, natural plant fibers are used to ensure a renewable cycle of production while also redefining the traditional “plastic-taste” characteristics many people associate with water pouches to a smoother, cleaner taste. Engineering, sustainability, and business and public service practice have been used in an interdisciplinary way to prepare this product for its intended use such as in school, for travel, and for the outdoors. According to the collected outreach, many indicated that they feel as though there is a need for a product that allows for the feeling of water security which can include carrying any personal belongings as well. Marketing strategies such as logo creating and online outreach continually influence product design, up until production would take place following the finalized design.

Is there a mismatch between urban farmers’ perceptions of their farm’s environmental sustainability and its actual environmental impact? Focusing on the use of water and nutrients on each farm as described by the farmers through interviews, it is evident that there is some level of disconnect between ideals and practices. This project may aid in bridging the gap between the two in regard to the farmers’ sustainability goals. This project will move forward by continuing interviews with farmers as well as collecting soil and water from the farms in order to more accurately quantify the sustainability of the farms’ practices. This project demonstrates that there is some degree of misalignment between perception and reality. Two farms claimed they were sustainable when their practices did not reflect that, while 2 farms said they were not sure if they were sustainable when their practices indicated otherwise. Samples from two farms showed high concentrations of nutrients and salts, supporting the idea that there may be a mismatch between perceived and actual sustainability.

Police use of force is a controversial practice on both the political stage and by scholars of criminal justice. Scholarly research has highlighted best practice for police departments’ use of force policies. Diverging from these policies may produce ineffective and harmful use of force practices within departments. Because of these potential consequences of police departments diverging from research-based evidence, it is necessary to identify when recommended policy is not being utilized. The purpose of this study is to identify whether there are points of dissent or congruence between criminal justice scholars and police departments with regards to use of force policy. Efforts have been made to empirically identify best practices of use of force policy. The findings of this study indicate that points of dissent do exist in the policies of police departments in the U.S. and the policy recommendations of criminal justice scholars. The implications of these findings include reform to the use of force policies of police departments to more accurately reflect the policies recommended by scholars in the use of force.

An in depth look at the rhetoric behind the campus carry debate at the University of Texas at Austin. This thesis researched and examined primary sources from The Daily Texan and The Austin-American Statesman attempting to analyze what was at stake for both sides of the argument and what the most effective rhetorical tool was.