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Free-Form Dithering
No full textIn this paper, we will present free-form dithering, a function-based dithering parallel dithering framework. The free-form dithering framework is appropriate to use in real-time applications it is straightforward to implement its parallel algorithms with GPU-based shader languages. This framework is implicit based on the sense that we construct hatching curves by altering the shapes of hatching curves using isocurves that are defined by type distance functions. Using distance functions allows us to precisely control the frequency of isocurves
Spectroscopic Studies of Stars and Black Holes Across Cosmic Time
No full textIn this work, I present my spectroscopic studies of galaxy evolution across a large majority of cosmic time (0 ��� z ��� 9). My career to this point has two distinct phases: pre-JWST, when I utilized spectroscopy from HST to study star formation, dust attenuation, and accreting black holes out to the peak of cosmic star formation rate and active supermassive black hole density (cosmic noon; z ��� 2), and post-JWST, where my focus shifted to this new observatory to push the study of galaxy evolution to some of the earliest known galaxies at z ��� 8.
In the pre-JWST era, I used HST grism spectroscopy to study star formation rates and histories as well as dust attenuation by using the near-IR Paschen lines of hydrogen. Emission from Paschen lines indicates near-instantaneous star formation, while probing regions inaccessible to UV or optical star formation tracers due to dust attenuation.
I also used HST grism spectroscopy to probe galaxies around cosmic noon which exhibit the extremely-high-ionization [Ne V] line. This spectral feature is a strong tracer of an ionizing spectrum powered by an accreting black hole, at least in this epoch of cosmic time.
These studies serve as optimal pilot campaigns for the JWST era, where JWST spectroscopy can probe these features out to much earlier epochs of cosmic time. I discuss the implications of JWST studies of Paschen-line star formation rates and dust attenuation out to cosmic noon, and studies of high-ionization emission lines in the epoch of Reionization.
Using early JWST spectroscopy in conjunction with HST spectroscopy and photoionization models, I develop a novel diagnostic to trace ionization from different sources at all epochs of cosmic time. This is designed specifically with elusive objects in the early Universe in mind, including Population III stars and accreting intermediate-mass black holes, in an effort to study the earliest stages of star formation and black hole growth.
We stand at the beginning of a new era in the study of galaxy evolution. With the incredible capabilities of JWST, we can study the physical mechanisms governing galaxies across cosmic time like never before
Modulating the Tumor Microenvironment via Plga-Mno2 Nanoparticle Mediated Hypoxia Reduction Leads to Increased Immune Responses Against Bone Metastases
No full textBone metastases result in a stark decrease in survivability in cancer cases, with most treatment options focusing on palliative care. Newer therapies, such as immunotherapies, use the patient���s immune cells to target tumors, sometimes to great effect. Though immunotherapies have been effective against some advanced-stage tumors, there has been limited success with bone metastases. Persistent hypoxia in the bone, necessary to maintain the hematopoietic stem cells, induces an immunosuppressive microenvironment that blunts the activity of cytotoxic immune cells against bone metastases. To address this, we have developed a nanoparticle capable of modulating the bone metastasis microenvironment to improve the antitumoral immune response. In this study, we use manganese dioxide nanoparticles (MnO2 NP) to catalyze the degradation of tumor-produced hydrogen peroxide, thereby generating oxygen. For improved biocompatibility and modulation of oxygen production, the MnO2 NPs were encapsulated into poly lactic-co-glycolic acid (PLGA-MnO2 NPs) to produce particles provide sustained high oxygen tension. The PLGA-MnO2 NPs were biocompatible, reduced hypoxia after penetration into the core of cancer spheroids, and decreased hypoxia-induced factor 1 alpha expression. Reducing hypoxia in the spheroid resulted in a decrease in adenosine, and lactate, immunosuppressive metabolites. Notably, the spheroids��� microenvironment changes enhanced NK cells' cytotoxicity, which obliterated the spheroids. Then, to address chronic hypoxia, we then developed altered the PLGA formulation to create poly lactic(50)-co-glycolic(50) (50:50 PLGA), poly lactic(75)-co-glycolic(25) (75:25 PLGA) and poly lactic acid (PLA) encapsulated MnO2 NPs. We then analyzed the oxygen kinetics due to each polymer type and showed that the 50:50 PLGA-MnO2 NPs exhibited the best short- and long-term control of hypoxia in cancer spheroids and the PLA-MnO2 NPs possessing the slowest O2 generation kinetics. In vivo, the 50:50 PLGA-MnO2 showed greater accumulation in the long bones and pelvis, common sites for bone metastases. The NPs decreased hypoxia in bone metastases and decreased regulatory T cell levels, resulting in enhanced survival of mice with established bone metastases
R.M. Pitts field not book: Pitts_4727-6208_assorted.pdf
No full textEach page/AK number corresponds to a karyotype slide data and/or unique specimen.Data pages for Pitts_4727-6208_assorted corresponding to unique identifiers of specimens/samples examined for biological research. Specimens are primarily housed at Texas A&M University; Biodiverstiy Research and Teaching Collection
The Role of Reactive Oxygen Species in Response to Chronic Ischemia and Exercise Training Within the Coronary Microcirculation of Swine
No full textThe overall goal of this thesis was to explore adaptations in the contribution of reactive oxygen species (ROS) to coronary microvascular function in response to chronic ischemia and exercise training. The main hypothesis of this study was that superoxide and NADPH oxidase (NOX)-derived ROS would contribute to vasodilation of coronary arterioles and that the contributions of these ROS would be impaired by chronic ischemia and ameliorated with exercise training. These studies utilized a swine model of chronic ischemia via occlusion of the proximal portion of the left circumflex artery with an ameroid occluder while exercise adaptations were examined via the completion of a 14-week progressive (5 days/week) treadmill regimen. Functional pressure myography experiments were performed on isolated arterioles from occluded and nonoccluded regions of sedentary and exercise-trained swine. Additionally, microvascular endothelial cells and arterioles were isolated for high performance liquid chromatography (HPLC) to examine superoxide anion levels and immunoblot to evaluate protein levels of superoxide dismutase (SOD), p22phox, and NOX isoforms.
Functional microvascular studies demonstrated that exercise training produced a rightward shift in vasodilation to the endothelium-dependent agonist, bradykinin, when scavenging superoxide with tempol, independent of occlusive treatment. Further experiments with the NOX1/4 inhibitor, GKT136901, revealed attenuated dilation after exercise training plus occlusion, but not with either exercise or occlusion alone. HPLC revealed that there were no differences in the basal or bradykinin-stimulated production of superoxide anion, regardless of occlusion or exercise. Furthermore, immunoblot analyses revealed decreased NOX2 protein after exercise with no differences found in NOX1, NOX4, p22phox, or SOD protein levels.
Together, these studies demonstrate that exercise-training stimulates independent contributions of both superoxide and NOX1/4-derived ROS to endothelium-dependent, bradykinin-mediated dilation of swine coronary arterioles. It is evident that exercise training produces cellular adaptations within the coronary microcirculation resulting in the contribution of ROS to vasodilation, and subsequently, increases in coronary blood flow. While we determined that ROS play a role in exercise-induced adaptations in the coronary microcirculation, additional study of specific sources and downstream effectors of these ROS are warranted
The How and Why of Realness: Reconceptualizing Identity Management and Examining Relationships with Authenticity and Motivation in a U.S.-Based LGBTQ2+ Sample
No full textIn this dissertation I examined whether the relationship between the identity management behaviors of LGBTQ+ employees and workplace outcomes (work engagement and affective well-being) is mediated by authenticity. Furthermore, I considered whether autonomous and controlled motivations for identity management behaviors moderate this relationship. In doing so, I add to identity management research that presumes but rarely tests the mediating effects of authenticity and I question the presumption that LGBTQ+ employees are always motivated to share their identities for autonomous reasons and hide them for controlled reasons. Additionally, I explored an alternative approach to measuring identity management behaviors, dividing them into verbal and nonverbal behaviors. Using a correlational design, I collected survey-based quantitative data from 456 LGBTQ+ identifying workers through the online data collection platform Prolific during the months of October and November 2023. Analyses conducted using the PROCESS macros indicated that the relationship between closed communication (e.g., verbal concealment and nonverbal suppression) and outcomes was mediated by authenticity, but this was not the case for open communication (e.g., verbal disclosure and nonverbal expression). There was an interaction effect between autonomous motivation and identity communication behaviors, such that for individuals with lower levels of autonomy, engaging in more open communication behaviors and/or more closed communication behaviors predicted diminished feelings of authenticity as well as reduced outcomes. Based on exploratory path analyses, the division of open communication into verbal and nonverbal behaviors better represented the true population model than combining these behaviors into one variable, however, there was no difference in model fit when closed communication was divided into verbal and nonverbal behaviors compared to a single-variable measure. I conclude by discussing theoretical and practical implications of these findings and propose future directions for this research
When Modes of Learning Shift Unexpectedly: How Instructors Choose Online Teaching Strategies
No full textThis study examined how in-person instructors selected online teaching and learning strategies when shifting to a different mode of learning during the COVID-19 pandemic. As many in-person instructors have little to no experience with online learning or instructional design, examining how strategies were selected during this time provides an understanding of what strategies worked, the challenges in shifting to a different mode of learning, and practices that were retained moving back to in-person instruction. The findings revealed that instructors selected strategies during these shifts through adapting existing in-person instructional strategies to address the changing circumstance
Essays on Social Preferences
No full textThis dissertation includes three essays in the field of behavioral economics, with a special focus on social preferences using laboratory experiments. The first essay investigates the influence of patient autonomy on doctors��� performance. Using a theory-driven laboratory experiment, I find that when the patient is not able to assess the doctor���s diagnostic precision, for those patients who are not fully compliant with doctors��� advice, doctors will reduce their investment of effort in the diagnosis. This reduction is the largest among those doctors who prioritize patients��� well-being. The experiment also investigates two institutional changes, communication and reputation, which both effectively improve patients��� well-being. This study contributes to experimental health economics by uncovering the potential detrimental effect of patient autonomy on a doctor���s performance and the patient���s health status.
The second essay explores the effectiveness of two punishment strategies for addressing the free-rider problem in public goods production. By varying the timing of punishment in a public good game, we differentiate between the Post-Punishment rule, expected to induce emotional arousal, and the Pre-Punishment rule, aimed at strategic considerations with minimal emotional impact. Pupil dilation data from eye trackers support our hypotheses, revealing that the Post-Punishment rule���s success relies on negative emotions, while the Pre-Punishment rule does not. This study sheds light on the role of negative emotions in punishment efficacy and introduces a novel punishment rule that operates independently of negative emotional responses within a group.
The third essay examines the trade-offs individuals make between money, honesty, and altruism through a sender-receiver game that allows truth-telling, selfish lies, and altruistic lies. We propose a theoretical model identifying five unique types of senders. Experimental findings show prevalent yet diverse patterns of trade-offs among these three domains of concern. This research adds to the literature on lying behavior by revealing varied preferences across moral domains and a widespread
propensity for costly altruistic lies
Neoconservatives and Taiwan: Adherents of Conservative Precedent or Advocates for Liberal Interventionism?
No full textDuring the 1990s neoconservatives grew concerned over a burgeoning People���s Republic of China (PRC) threatening the newly democratic government of Taiwan. They wanted the United States to bolster Taiwan���s standing in the international community, commit to defend Taiwan, end strategic ambiguity, prevent further entrenchment of the PRC in international organizations, and push for closer if not official relations between the United States and Taiwan. Neoconservatives frequently employed Wilsonian rhetoric to shore up support for Taiwan. Despite this liberal notion, their foreign policy positions and thinking built on the likes of the China Lobby and New Right. By analyzing neoconservative viewpoints on U.S. policy towards Taiwan one can see how evolved earlier conservative positions despite accusations that they carried on liberal tenets in foreign policy
Thermal Lethality Validation for Human Pathogenic Salmonella enterica on Chicken Feathers and Blood During Simulated Low-Temperature Rendering
No full textPoultry carcass offal rendering is the process in which poultry inedible and carcass waste materials are converted into high-quality protein meals such as poultry, feather, and blood meal, and other commercial byproducts through physical and chemical transformation using sustained heat application, moisture extraction, and fat separation. Nevertheless, the presence of pathogens in animal feed that have been linked to ingredients obtained from rendered products has raised concerns over the process���s capability to reduce food safety hazards to acceptable levels that might be transmitted to animal feeds. This study was conducted to validate the inactivation, and determine the death kinetics, of a thermotolerant human pathogenic Salmonella enterica in chicken feathers and blood during simulated low-temperature dry rendering conditions. Chicken feathers and blood were inoculated with Salmonella enterica serovar Senftenberg 775W and heated to 60, 70, or 80 ��C for 60, 20, and 5 min, respectively. Complete block design experiments were conducted and three samples for each product were processed at each time point and replicated three times (N=3). After thermal treatment, samples were serially diluted and selectively enumerated after incubating for 24 h at 37��C. Experimental data were log-transformed and the Geeraerd non-linear inactivation model was used for curve and data fitting with the Microsoft Excel Add-In software toolkit GInaFiT. The data analysis showed D-values and observed shoulder periods decreased with increase in processing temperature for both feathers and blood. D-values were 2.23��0.045, 0.66��0.135, and 0.29��0.0225 min for chicken feathers and 2.22��0.2, 0.46��0.0175, and 0.27��0.05 min for chicken blood at 60,70, and 80 ��C respectively. Secondary model analysis showed that the maximum inactivation rate was positively correlated with the processing temperature. Model predicted Kmax values calculated per minute were 1.05��0.07, 3.63��0.20, and 8.37��0.67 for chicken feathers, and 1.06��0.10, 5.06��0.20, and 8.53��1.10 for chicken blood at 60, 70, and 80 oC respectively. Study findings validated ability of low-temperature rendering conditions to significantly reduce Salmonella in poultry rendered product to below detectable values. They also provide rendering industry a supporting tool for food safety validation and food safety regulatory standards compliance