CU Dissertations

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KRAS 4B Silent Mutations in NIH/3T3 Cells Lead to a Tumorigenic Phenotype
Degree Awarded: Ph.D. Biology. The Catholic University of America, It has long been assumed that silent mutations do not affect the fate of a particular protein because the amino acid sequence remains unchanged. However, we are learning that redundancies in the genetic code can lead to changes in protein expression and subsequent phenotypic changes. Surprisingly, silent mutations have recently been associated with more than fifty human diseases. KRAS, the most frequently mutated proto-oncogene in human cancers, is often constitutively activated in cancers that are associated with a poor prognosis. While the majority of research on KRAS mutant cancers has focused on missense mutations at G12 (glycine, residue 12), G13 (glycine, residue 13), and Q61 (glutamine, residue 61), there exists a subset of cancer patients with non-random clustering of silent mutations at G12, G13, and G60. The goal of this study was to examine these silent mutations in the human KRAS 4B gene and begin to clarify the role synonymous codons play in conferring tumorigenic phenotypes on mouse NIH/3T3 cells. We present data showing silent mutations in the human KRAS 4B gene at G12, G13, and G60 altered KRAS protein expression levels when expressed in NIH/3T3 cells and affected activation status of RAS-associated signaling pathways. Moreover, NIH/3T3 cells that expressed the human wild-type (WT) KRAS 4B sequence were contact inhibited, whereas some of the cells transfected with silent KRAS mutations resulted in loss of contact inhibition. The KRAS silent mutations also affected proliferation rates, saturation densities, migration, and invasion. This study links silent mutations in the KRAS gene to tumorigenic phenotypes in mammalian cells and uncovers a previously underappreciated aspect of cancer research.
Characterization of the Atmosphere as a Random Bit-Stream Generator in a Weak Turbulence Regime
The purpose of this dissertation is to investigate the extent to which atmospheric turbulence can be exploited as a robust random number generator. Atmospheric turbulence is considered an inherently random process, due to the complex non-homogeneous system composition and its sensitivity to changes in pressure, temperature, humidity, wind speed and direction. This work describes the background theory on atmospheric turbulence, which attempts to describe its dynamic behavior, as well as experimental work. A Mach-Zehnder interferometer was designed, built, and used to characterize the work in this dissertation; this sensor system enables the collection of empirical data of the phase fluctuation in the temporal domain introduced to an optical beam propagating through the atmosphere. The recorded phase fluctuations were converted into bit streams that were further analyzed in order to search for evidence of non-random properties. Empirical data and results, which attempt to characterize the degree of randomness in the noise introduced into the temporal phase component of an optical wave propagating through the atmosphere as a function of the atmospheric turbulence in the weak turbulence regime, are presented here for the first time., Degree awarded: Ph.D. Electrical Engineering and Computer Science. The Catholic University of America
Effects of Near-Fault Translational and Torsional Ground Motions on Dynamic Response of Single-Story Buildings
Rotational components of ground motions, torsion about the vertical axis and rocking about the horizontal axes, have caused significant damage to engineering structures and failures to bridges. Several analytical and experimental studies have been conducted to investigate the effect of these components on structures. Rotational components of ground motions cannot be measured directly and have been measured by rotational sensors only for explosions and by strong motion arrays only for far-field seismic events. Therefore, in the absence of near-fault records of differential ground motions, the characterization, parameterization, modeling and simulation of strain, rocking, and torsional ground motions in the vicinity of the fault, as well as the systematic investigation of their effects on the dynamic response of engineering structures becomes an important issue.In this study, the dynamic ground deformations generated by Mavroeidis and Papageorgiou (2010a) for two well-documented seismic events (i.e. 1979 Imperial Valley and 1999 Izmit earthquakes) based on the discrete wavenumber representation method (Bouchon and Aki, 1977; Bouchon, 1979a) are utilized to obtain torsional and rocking ground motions and their associated distributions on the gridded region in the vicinity of each earthquake. These synthetic ground deformations are used in this study to investigate the effect of the biaxial action of recorded translational ground motions and synthetic torsional ground motions on the response of symmetric and asymmetric structures. In the current seismic deign codes and standards, this torsional ground motion accounts by the shifting of the center of mass to produce the desired results. In order to investigate the effects of torsional motions on the structural responses, a software has been developed to study the linear and nonlinear response of buildings under biaxial and torsional seismic ground excitation. The program is able to perform nonlinear time history analysis based on the force- and displacement-based formulation methods developed by Spacone (1992). The biaxial and uniaxial Smooth Hysteresis Models developed Simeonov et al. (2000) are employed to model the hysteresis behavior of elements in the context of the moment-curvature relationship. The uniaxial and biaxial smooth hysteresis behaviors of the material, similar to the widely used Bouc-Wen model are employed in this research. Various numerical approaches such as the implicit Runge-Kutta, Newton-Raphson and Newmark methods are used to solve the differential equations that govern the dynamic response of the system.Finally, parametric linear and nonlinear analyses are performed for a series of symmetric and asymmetric single-story buildings to investigate the influence of the natural and accidental torsional eccentricity on the response of structures. The structural models are subjected to bidirectional recorded translational motions and synthetic low-frequency angular accelerations from the 1979 Imperial Valley and 1999 Izmit earthquakes. In order to examine the response of structures subjected to synthetic torsional motions containing high-frequency components, the bidirectional translational records from the 1986 Taiwan earthquake at FAT-1 station and the associated synthetic torsional motion, generated by the Surface Distribution Method, are also used to conduct parametric nonlinear analysis. The equivalent accidental eccentricity is developed through the mathematical formula for structures subjected to the combination of the bidirectional translational motions and torsional ground motions. The torsional amplifications developed in structures either by accidental torsion or by synthetic ground differential deformations are not significant for the lower periods. The nonlinear behavior of the structure imposed by strength eccentricity is also explored, while the results are displayed in the biaxial Base Shear and Torque (BST) Surface, inferred for the possible collapse mechanisms regardless of the analysis results., Degree awarded: Ph.D. Civil Engineering. The Catholic University of America
Characterization of the Acoustic Field in Marine Environments with Anthropogenic Noise
Most animals inhabit the aquatic environment are acoustical-oriented, due to the physical characteristics of water that favors sound transmission. Many aquatic animals depend on underwater sound to navigate, communicate, find prey, and avoid predators. The degradation of underwater acoustic environment due to human activities is expected to affected these animals' well-being and survival at the population level. This dissertation presents three original studies on the characteristics and behavior of underwater sound fields in three unique marine environments with anthropogenic noises.The first study examines the soundscape of the Chinese white dolphin habitat in Taiwan. Acoustic recordings were made at two coastal shallow water locations, Yunlin and Waisanding, in 2012. Results show that croaker choruses are dominant sound sources in the 1.2-2.4 kHz frequency band for both locations at night, and noises from container ships in the 150-300 Hz frequency band define the relative higher broadband sound levels at Yunlin. Results also illustrate interrelationships among different biotic, abiotic, and anthropogenic elements that shape the fine-scale soundscape in a coastal environment.The second study investigates the inter-pulse sound field during an open-water seismic survey in coastal shallow waters of the Arctic. The research uses continuous acoustic recordings collected from one bottom-mounted hydrophone deployed in the Beaufort Sea in summer 2012. Two quantitative methods were developed to examine the inter-pulse sound field characteristics and its dependence on source distances. Results show that inter-pulse sound field could raise the ambient noise floor by as much as 9 dB, depending on ambient condition and source distance.The third study examines the inter-ping sound field of simulated mid-frequency active sonar in deep waters off southern California in 2013 and 2014. The study used drifting acoustic recorder buoys to collect acoustic data during sonar playbacks. The results show strong band-limited elevation (13-24 dB) of sound pressure levels for over half of the inter-ping intervals above the natural background levels.These three studies provide insights on the dynamics of marine soundscape and how anthropogenic activities can change the acoustic habitat by elevating the overall sound field levels., Degree awarded: Ph.D. Mechanical Engineering. The Catholic University of America
Quantitative Assessment of Optical Coherence Tomography Imaging Performance with Phantom-Based Test Methods and Computational Modeling
Optical coherence tomography (OCT) is a powerful medical imaging modality that uniquely produces high-resolution cross-sectional images of tissue using low energy light. Its clinical applications and technological capabilities have grown substantially since its invention about twenty years ago, but efforts have been limited to develop tools to assess performance of OCT devices with respect to the quality and content of acquired images. Such tools are important to ensure information derived from OCT signals and images is accurate and consistent, in order to support further technology development, promote standardization, and benefit public health. The research in this dissertation investigates new physical and computational models which can provide unique insights into specific performance characteristics of OCT devices.Physical models, known as phantoms, are fabricated and evaluated in the interest of establishing standardized test methods to measure several important quantities relevant to image quality. (1) Spatial resolution is measured with a nanoparticle-embedded phantom and model eye which together yield the point spread function under conditions where OCT is commonly used. (2) A multi-layered phantom is constructed to measure the contrast transfer function along the axis of light propagation, relevant for cross-sectional imaging capabilities. (3) Existing and new methods to determine device sensitivity are examined and compared, to better understand the detection limits of OCT.A novel computational model based on the finite-difference time-domain (FDTD) method, which simulates the physics of light behavior at the sub-microscopic level within complex, heterogeneous media, is developed to probe device and tissue characteristics influencing the information content of an OCT image. This model is first tested in simple geometric configurations to understand its accuracy and limitations, then a highly realistic representation of a biological cell, the retinal cone photoreceptor, is created and its resulting OCT signals studied.The phantoms and their associated test methods have successfully yielded novel types of data on the specific performance parameters of interest, which can feed standardization efforts within the OCT community. The level of signal detail provided by the computational model is unprecedented and gives significant insights into the effects of subcellular structures on OCT signals. Together, the outputs of this research effort serve as new tools in the toolkit to examine the intricate details of how and how well OCT devices produce information-rich images of biological tissue., Degree awarded: Ph.D. Electrical Engineering and Computer Science. The Catholic University of America
Polarimetric Radar Scattering Analysis in a Maritime Environment
This dissertation evaluates multiple effects that will cause a satellite borne radar to observe transformation of the transmitted polarization by an ocean surface. Knowing the surface conditions over large swaths of ocean is very important for both global weather prediction and for safety of navigation at sea. Fully polarimetric linearly polarized ocean observation radars use the linear cross-polarized ocean response to obtain an assessment of the surface wind vectors. However, radar technology is evolving. More compact hybrid polarization radars that transmit a single circular polarization, and then simultaneously receive two orthogonal linear polarizations are expected to obtain near fully polarimetric capability with a significant savings in weight, volume, and complexity. The models used by fully polarimetric linearly polarized radars to obtain the surface wind vectors are empirical, and not usable for hybrid compact polarimetric radars. The literature survey indicated two areas needed investigation to develop ocean observation capabilities for hybrid compact polarimetric radar. The first is for antenna cross-polarization isolation models specific to hybrid polarization radars. The second is for improved understanding of the nature of the ocean's polarimetric response to hybrid polarizations. Conclusions include that hybrid polarizations provide opportunities to polarimetrically isolate surface features, including surface roughness, the surface specular response, and breaking waves. These features should provide insight into surface winds, wave steepness, and sea state., Degree awarded: Ph.D. Electrical Engineering and Computer Science. The Catholic University of America
Employing pFUS for Treatment of Peripheral Arterial Disease via Homing of Infused Bone Marrow Stromal Cells
Peripheral artery disease (PAD) manifests from vascular blockage or trauma to a region causing restricted flow of oxygen-rich blood to tissues and organs Treatment options for PAD include lifestyle modification, pharmacotherapy, and revascularization, but they often fail. Clinical data shows that administration of bone marrow stromal cells (BMSC) can provide therapeutic benefits to!promote regeneration of damaged tissue, treat inflammation, and induce angiogenesis. However <<3% of IV-infused cells arrive at the target site. Pulsed focused ultrasound (pFUS) has been used as a noninvasive and nondestructive modality to enhance tissue permeability and retention in drug delivery through physical alterations in tissue. The goal of the proposed research is to employ pFUS exposures to elicit local molecular responses for enhancing homing and retention of BMSC in PAD tissues to improve vascularization and reestablish perfusion blood flow. Hamstrings of healthy mice were treated with pFUS and harvested at various time points to characterize the biological response of tissue. The results demonstrated significant elevations in chemoattractants (homing factor) as early as 10min and subsided by 60hrs post-pFUS. From this data, an optimal time window for maximal BMSC homing to pFUS treated site was suggested. Maximum homing of IV-infused BMSC occurred pre-pFUS and up to 16 post-pFUS demonstrating enhance homing of cells by pFUS. After creation and validation of the PAD model using laser Doppler perfusion imaging, the ischemic limb was treated and harvested at various days after ischemic induction to demonstrate the feasibility of generating a transient inflammatory response outside innate inflammatory response of the disease. Fourteen days after the induction of PAD, the innate inflammatory response had subsided and pFUS was used to stimulate an inflammatory response and enhance cell homing to pFUS treated site. When therapeutic efficacy was tested for 7 weeks in aged (≥12 months) mice with PAD and treatment,(BMSC+pFUS), given 14days after ischemic induction, perfusion blood flow was significantly enhanced in the treatment group versus control. The results demonstrated the therapeutic benefits of combining pFUS and cells that can be translated in other vascular disease models. The implications of this research have the potential to enhance regenerative medicine., Degree awarded: Ph.D. Biomedical Engineering. The Catholic University of America
Ultrasound Mediated lntracellular Drug Delivery in 2D Biological Scaffolds
Successful intracellular drug and gene delivery represents a major goal for medical researchers. Sonoporation (i.e. the formation of pores using sound) is considered one of the most promising techniques, especially since it is non-destructive and as it can be carried out deep inside the body under image guidance. The mechanism of sonoporation is not fully understood. Presently, the vast majority of in vitro sonoporation investigations are carried out on cells in monolayer in plastic dishes. These systems are problematic from a variety of aspects. Ultrasound interaction with the wells, themselves acoustically incompatible, can result in unwanted phenomena such as mode conversion, heat generation, and standing waves. These factors combined can lead to uncertainties of up to 700% in the actual ultrasound exposure experienced by cells. Biological scaffolds can serve as an artificial extra cellular matrix to support different cell processes. Compared to plastic dishes, they more realistically resemble the in vivo environment in terms of how ultrasound interacts with cells and the extracellular matrix. The goal of this project was to develop a more biologically and acoustically compatible platform for investigating the process of sonoporation. I have developed a prototypical 2D biological scaffold, based on chitosan and gelatin. Scaffolds formulation was optimized for both cell adhesion and proliferation. I have also designed and custom built an acoustically compatible treatment chamber, where problematic issues of current setup were minimized. The acoustic activity inside the chamber was verified. The acoustic compatibility of the scaffolds was demonstrated using B-mode diagnostic ultrasound imaging and transmission test, compared to traditional culture dish. To study cell survival, sonoporation experiments were carried out over a range of ultrasound intensities and durations in this novel system. High cell survival (i.e. 83%) was achieved at 0.8 w/cm2 for 30 sec. Fluorescent imaging revealed successful intracellular delivery of nanoparticles at this ultrasound exposure. At the same ultrasound exposure, when carried out in a well plate, lower cell survival and higher variability was obtained. Acoustic incompatibility of culture plates produces less predictable results. This new platform was more acoustically compatible, allowing more predictable ultrasound exposures, and more consistent results., Degree awarded: Ph.D. Biomedical Engineering. The Catholic University of America
Literary Structure and Character in Proverbs 30
This dissertation highlights three main points about Proverbs 30, which can be summarized in the following conclusions:1. Proverbs 30 presents a רִיב or "protest" (cf. v. 33) by the "Godly Believer" against the "Ungodly Hypocrite." The "Godly Believer" expresses his objection in words addressing the "Ungodly Hypocrite's" ungodly statement (vv. 1-4), ungodly actions (vv. 11-14) and ungodly authority (vv. 18-20, 21-24). The "Ungodly Hypocrite" is a protester (v. 1) and apostate who feigns to be religious (vv. 5-6, 12). The "Godly Believer" is an epistemologist (vv. 2-3), a religious man (v. 4) and a believer (vv. 4-9). The "Ungodly Hypocrite" is a highly positioned person in society (vv. 1, 10, 27, 30) who, by his ungodliness (v. 1, 11), hypocrisy (vv. 8-9, 12), arrogance (v. 13) and disdain (v. 14) consumes the "Godly Believer" (vv. 11-15a), who is, by virtue of his social position, subservient to the "Ungodly Hypocrite" (vv. 1-2, 10). The "Ungodly Hypocrite" is a predator not only of the "Godly Believer" but also of all God-fearing people (vv. 18-20) and the main reason for an unbalanced and "quaking" society (vv. 21-23). By contrast, the curse proclaimed by the "Godly Believer" invokes the definitive consumption or elimination of the "Ungodly Hypocrite" (vv. 15b-17) and the self-destruction of the ungodly society (vv. 18-20). Besides the curse and destruction of ungodly men, the only possibility to recover a balanced society (vv. 24-28) is the conversion or silencing of the ungodly society represented by the "Ungodly Hypocrite" (vv. 5-6; 32-33). Thus, as the head or ruler of the people (vv. 1, 14, 29-31), he is encouraged to repent (v. 5-6), consolidate his position and perform his duties (vv. 29-31) according to the established statutes of God-fearing people (v. 32-33). 2. The characteristic chiastic formula A ≤ B in vv. 2-3, 4, 11-14, 15b-17; 18-20; 21-23 and 29-31 shows Proverbs 30 to have a chiastic structure, in which the acts of the "Ungodly Hypocrite" are gradually presented and elaborated . The statement of "ungodliness" and the hypothesis of "nothingness" in v. 1 lead to the denial of ungodliness and nothingness in vv. 2-4 and the rebuke of the ungodly society in the contrast to the balanced and sane society in vv. 5-10. Besides the theoretical un godliness cited in v. 1, practical ungodliness is presented in vv. 11-15a, elaborated in vv. 15b-16, and repeated and condemned in v. 17. Ultimately, by the acts of self-destruction in vv. 18-20, the rebuke of the ungodly society is followed by vv. 21-23, with encouraging examples of a balanced and sane society in vv. 24-28, as presented by the affirmation of the king's position in vv. 29-31 and the anticipation of conversion in vv. 32-33. 3. The intention of Proverbs 30 is to silence (v. 33) and put an end to the imbalanced society supported by the ungodly behavior of its ungodly leader, who formally belongs to the God-based society (vv. 1, 5-9) but whose provocation (v. 1) and behavior (vv. 11-14) support the ungodly, hypocritical and arrogant society (vv. 11-14, 21-23) that can only be ended by a curse (vv. 15b-17) and self-destruction (vv. 18-20) or, alternatively, by repentance (vv. 5-6) and conversion (vv. 32-33). The problem of the ungodly society was not as emphasized during the time of the united monarchy of Israel as during Hezekiah's monarchy and the time of Babylonian exile (cf. Ezekiel 20). Since Proverbs 30 belongs with Hezekiah's collection, it may date to the rule of the religious and obedient King Hezekiah and his ungodly and apostate son Manasseh. As for further research, this study has portayd Proverbs 30 as a verbal expression of an objection to the leader's ungodly behavior and actions, encouraging him to take the correct path of life in leading his people. The same idea of leadership is presented in Prov 31:1-9, where a warning and caution to a king are presented. The acrostic hymn about a capable woman in Prov 31:10-31 is a concluding masterpiece alluding to a godly and skillful people under the vassalage of a foreign kingdom, which is compared with a woman. Although subject to and dependent on her husband, she behaves in godly manner. She is prosperous, generous and successful within her family. Her behavior contrasts to that of the ungodly, arrogant, deteriorating, self-destructive and unsuccessful leadership presented in Proverbs 30. The interrelationship between Proverbs 30 and 31 is both remarkable and extensive, which would merit further detailed investigation. Since Proverbs 30 and 31 go together, the next step would be an extensive treatment of Proverbs 31. The themes of Proverbs 30 and 31 are compatible parts of biblical wisdom from the period between and after King Hezekiah and the time of Israel's vassalage and submission to powerful oppressor kingdoms., Degree awarded: S.T.D. Biblical Studies. The Catholic University of America
The Relationship of Stroke Patients' Functional and Cognitive Status And Caregivers' Resilience to Caregiver Burden
The Relationship of Stroke Patients' Functional and Cognitive StatusAnd Caregivers' Resilience to Caregiver BurdenMargaret D. Nolan, Ph.D.Director: Jean Toth, Ph.D. Currently it is estimated that 795,000 persons experience a stroke every year. Of that number up to one-third of survivors will be permanently disabled. It is neither financially feasible nor desirable to place these disabled stroke survivors in long-term care facilities to provide them with the needed assistance if they can be cared for at home. Frequently, the care of these patients is assumed by family members or friends. However, providing care has been shown to be burdensome for some caregivers of stroke patients (Johnson, 1998; Scholte op Reimer, deHaan, Pijnenborg, Limburg, & van den Bos, 1998a; Van Puymbroeck, Hinojosa, & Rittman, 2008). The factors that contribute to development of caregiver burden have been studied by numerous researchers, but findings are inconclusive (Jeng-Ru, Hills, Kaplan, & Johnson, 1998; McCullagh, Brigstocke, Donaldson, & Kalra, 2005; Nelson, Smith, Martinson, Kind, & Luepker, 2008; Vincent, Desrosiers, Landreville, & Demers, 2009). The contribution of the stroke patients' functional and/or cognitive disabilities to the caregiver's burden level is not clear as a result of contradictory findings in the published research. Further, resilience has not been measured in stroke caregivers and evaluated as a possible mediating factor in burden's development. This study sought to clarify those interrelationships. A descriptive correlational design was used in this study. Fifty-six stroke patient and caregiver dyads were evaluated at least two weeks after the stroke patient returned to the home setting after experiencing an acute stroke. All of the participants were adults who spoke English. Stroke patients were evaluated functionally with the Barthel Index, and cognitively with the Mini-Mental State Exam by the investigator. Caregivers self-administered the Resilience Scale, the modified Zarit Burden Interview, and a demographic data collection tool. Demographic data was evaluated with descriptive statistics and the hypotheses were tested using multiple regression. Regression analysis indicated that the functional status and cognitive status of the stroke patients were not significantly related to the burden level of their caregivers. However, the caregivers' personal resilience level was significantly related to caregiver burden [F (4, 50) = 4.10, p = 0.048]. Demographic data analysis revealed that there was also a significant relationship between the caregivers' perception that their own physical condition made it difficult to provide care and their burden level. This study's findings contribute to the existing body of knowledge regarding caregiver burden in stroke patients. Identification of factors that contribute to or mediate the development of caregiver burden may aid nurses and other health care providers in identifying caregivers who are at risk for developing burden, and ultimately assist in maintaining stroke patients in their home setting long-term., Degree awarded: Ph.D. Nursing. The Catholic University of America
The Theory of the Person in Robert Spaemann's Ethical Assessments
Robert Spaemann has written widely on a variety of philosophical topics and prominent figures in the history of philosophy. He is especially notable for his work in the philosophy of the human person. However, Spaemann has also written on many particular ethical controversies such as abortion, the use of nuclear power, and euthanasia. This dissertation argues that there is a relationship between Spaemann's treatment of particular ethical issues and his philosophical anthropology. In various ways, his ethical assessments are informed by his theory of the human person. The first chapter discusses Spaemann's understanding of the human person as a self-transcendent being. The analysis focuses on Persons, Spaemann's most comprehensive exploration of the subject. The chapter begins by examining Spaemann's three typical ways of speaking about self-transcendence. The individuality and intersubjectivity of the human person are then considered. Finally, the chapter ends with an examination of Spaemann's descriptions of some "ordinary" manifestations of self-transcendence: promising, forgiveness, and death. The second, third, and fourth chapters turn to Spaemann's ethical assessments of six moral controversies. The second chapter considers the issues of genetic manipulation and the use of embryos. The third chapter considers abortion and nuclear power. The fourth chapter considers euthanasia and "brain death." In each case, the methodology is the same: first, Spaemann's primary criticisms of each practice are reviewed; then, the various ways in which his theory of the person enters into and influences the ethical assessment are identified and explained. The dissertation concludes with a more precise statement of the various ways in which Spaemann's ethical assessments draw upon his philosophical anthropology: his assessments are grounded metaphysically, epistemologically, and dialectically in his theory of the person. It is suggested that this theoretic grounding imparts an attractive unity to Spaemann's applied ethics. However, it is also suggested that this grounding makes the persuasiveness of his assessments ultimately dependent upon the cogency of his theory of the person and his understanding of the nature of philosophy., Degree awarded: Ph.D. Philosophy. The Catholic University of America
The Role of Learning in Age-Related Differences in Decision Making under Uncertainty
The global population is growing older. In addition to this demographic change, individuals are increasingly being asked to take personal responsibility for their own economic welfare. The confluence of these trends can have profound economic consequences that underscore the importance of understanding decision making in older adults. While the study of decision making and aging has grown in recent years, there have been two important limitations in this work to date. First, researchers often assume that when people make decisions, they calculate the expected value of each option by multiplying the value of each by the probability that it will occur. This overlooks the possibility that people may focus more on value or probability when making decisions. Second, despite the fact that age differences in decision-making have been linked to learning deficits, interpretations in the literature often ignore the influence these deficits have on decisions. To address these limitations, this dissertation focused on the ability of older adults to learn probabilistic relationships, and how this learning influences decision-making behavior. The first study examined learning of stable, or consistent, probabilistic relationships in healthy and young adults. The study revealed age differences in learning, suggesting that young and older adults may use different cognitive systems when learning stable probabilistic relationships. The second study built upon the first by examining age differences in learning both stable and volatile, or unstable, probabilistic relationships. This study revealed that individual differences in learning predict decision-making performance. Specifically, learning stable relationships predicted performance on a stable decision making task while learning volatile relationships predicted performance on a volatile decision making task. Importantly, the converse relationships were not significant, revealing a dissociation between learning of stable and volatile relationships. Collectively, these results support the hypothesis that age-related deficits in learning underlie age differences in decision making and highlight the need to further characterize how learning and decision making interact with the aging process., Degree awarded: Ph.D. Psychology. The Catholic University of America
Rights and the Common Good: An Ethical Evaluation of the Exercise of the Natural Right of HIV/AIDS Patients to Marry in the Light of the Common Good
Rights and the Common Good: An Ethical Evaluation of the Exercise of the Natural Right of HIV/AIDS Patients to Marry in the Light of the Common GoodWilliam Neba, S.T.D.Director: Joseph E. Capizzi, Ph.D.HIV/AIDS can be transmitted through heterosexual intercourse, transfusion of infected blood, and from an infected mother to child through delivery. HIV--a retrovirus--is capable of mutating into various strands, which makes it difficult to develop a vaccine. While this is an on-going concern for the scientific community, another issue is facing the society today--whether an HIV/AIDS carrier can still insist on exercising his natural right to marry (ius connubii), given the risk of exposing an uninfected partner and possible offspring to a mortal, irreversible illness?This project addresses this question by first establishing the general principles pertaining to the meaning of natural rights. It elaborates on what they entail and the obligations that come with their exercise for the common good, and underlines that they can be limited. Then it shows that the Church recognizes the ius connubii and protects its exercise, especially by the sick--lepers and the insane--if they find willing partners. However, the Church also limits the exercise of the ius connubii by establishing impediments when such exercise threatens certain ecclesial goods. Next, the work lays out the data on HIV/AIDS to illustrate how it threatens the exercise of the ius connubii, with particular reference to Cameroon in sub-Saharan Africa. Finally, based on moral-ethical arguments, the project demonstrates that HIV/AIDS carriers that lack adequate access to medical assistance would face difficulties in fulfilling the responsibilities inherent in marriage. Furthermore, the research demonstrates that recent advances in antiretroviral therapy can help HIV/AIDS carriers have a better quality of life and even generate HIV-free children. Thus, the Church cannot establish HIV/AIDS an impediment to marriage, lest she risks unjustly restricting millions of the Christifideles from exercising their natural right to marry--a vocation embraced by the majority of the human race. Thus, this project, based on the weight of the moral-ethical arguments, concludes by proposing solutions to the aforementioned problems, with the aim of fighting this modern evil that has the potential to jeopardize not only the sanctity of marriage and family life, but also the future of the society as a whole., Degree awarded: S.T.D. Moral Theology/Ethics. The Catholic University of America
Polaronic Transport in Phosphate Glasses Containing Transition Metal Ions
The goal of this dissertation is to characterize the basic transport properties of phosphate glassescontaining various amounts of TIs and to identify and explain any electronic phase transitionswhich may occur. The P2O5-V2O5-WO3 (PVW) glass system will be analyzed to find the effectof TI concentration on conduction. In addition, the effect of the relative concentrations ofnetwork forming ions (SiO2 and P2O5) on transport will be studied in the P2O5-SiO2-Fe2O3 (PSF)system. Also presented is a numerical study on a tight-binding model adapted for the purposes ofmodelling Gaussian traps, mimicking TI’s, which are arranged in an extended network. Theresults of this project will contribute to the development of fundamental theories on theelectronic transport in glasses containing mixtures of transition oxides as well as thosecontaining multiple network formers without discernible phase separation.The present study on the PVW follows up on previous investigation into the effect on mixedtransition ions in oxide glasses. Past research has focused on glasses containing transition metalions from the 3d row. The inclusion of tungsten, a 5d transition metal, adds a layer of complexitythrough the mismatch of the energies of the orbitals contributing to localized states. The datahave indicated that a transition reminiscent of a metal-insulator transition (MIT) occurs in thissystem as the concentration of tungsten increases. As opposed to some other MIT-like transitionsfound in phosphate glass systems, there seems to be no polaron to bipolaron conversion. Instead,the individual localization parameter for tungsten noticeably decreases dramatically at thetransition point as well as the adiabaticity.Another distinctive feature of this project is the study of the PSF system, which contains two truenetwork formers, phosphorous pentoxide (P2O5) and silicon dioxide (SiO2). It is not usuallypossible to do a reliable investigation of the conduction properties of such glasses because thetwo network formers will tend to separate into different phases, making it difficult to obtainhomogenous samples. The PSF system proved easier to study than other systems. The hopping inthis system seems to be dominated by the Greaves mid-range mechanism. In addition, in samplescontaining the same proportion of iron, conductivities were found to not depend noticeably oncomposition, supporting the use of models focusing on the transition metal ions in calculatingconductivity. Despite ostensibly changing the structural and metrical properties of the network,the ratio of the concentration of the network formers only appears to have an effect on theconductivity through changing the inter-atomic distance of iron.The numerical model adds to the evidence for the dominating contribution on the nearestneighborordering of TI ions on the electrical properties of a glass; especially interesting is thereproducibility of the mixed-transition ion effect (MTE) in a numerical model where ensembleaverages are taken over possible arrangements. It was also determined that the disorder arisingfrom the spread between two types of traps can lead to a MIT as function of population.Finally, an outline of the notion of invariance in TI glasses is extended from work done by otherauthors, creating an opportunity for further research., Degree awarded: Ph.D. Physics. The Catholic University of America
The Ritual Dimension of John Cassian's Asceticism
John Cassian's two ascetic treatises were certainly influential in the history of the western monasticism. Scholarship on Cassian, often by necessity, focuses on Cassian’s sources in the desert tradition or his contemplative insight. The former, exemplified in the work of Robert Taft, approaches Cassian as a witness, albeit not wholly reliable, to the Egyptian practices. The difficulty with such an approach is obvious. Cassian’s account was not composed as objective history. In fact, Cassian himself noted that he wrote his two works in order to reorient the practices of the monasteries in Gaul. The second approach, exemplified in the work of Columba Stewart, while treating Cassian’s literary sources, focuses specifically on Cassian’s understanding of contemplation. These two methodologies, understandable given that Cassian treated the topic across The Institutes and The Conferences, has obscured the integral relationship between liturgical and contemplative prayer. The present study explores this relationship, especially within the frame of Cassian’s ascetic vision. After establishing Cassian’s life and writings, this study turns to outline Cassian’s ascetic vision. That is to say that Cassian wrote to establish an ascetic culture in which the inner and outer life of the monk were cultivated by the performances of the monastic community to receive the contemplative vision of God. The third chapter, then, turns specifically to Cassian’s depiction of prayer, both liturgical and contemplative. The final chapter explores two key themes within the discussion of Cassian’s theological influence, grace and spiritual knowledge. While the first is more contested, the latter has been influential in the history of biblical interpretation. Yet, both topics reveal how the contemplative goal and experience shaped Cassian’s understanding of significant theological topics. It is argued, then, that Cassian’s ascetic vision defied an easy distinction between the inner and outer monk, solitary and community life, grace and works, ritual and pure prayer., Degree awarded: Ph.D. Church History. The Catholic University of America
Augustine the Preacher and the Judgment of God
Although the judgment of God is a dominant theme in Augustine’s Sermones ad populum, it has not yet been studied effectively. The problem is that modern scholarship strives to relate the judgment of God to other aspects of Christian teaching, or to understand its place in Augustine’s own thought, without consideration of its relevance for the life of the individual members of the Christian community. Not enough has been said about Augustine’s concrete exposition and application of this teaching, that is, his efforts to bring the judgment of God to bear on individual behaviors, and thereby to establish a dynamic link between personal life experience and ultimate human destiny. This study provides a comprehensive overview of Augustine’s homiletic application of the various teachings that are associated with divine judgment. These include original sin; divine mercy and justice; God’s activity in the world; his desire for the salvation of sinners; the incomprehensibility of divine election; the need for faith, love, and repentance to be saved; divine displeasure with sins and approval of works of charity; the divinely appointed means for receiving the forgiveness of sins in the one true Church; God’s judgment on those who unworthily partake in Christian sacraments and rituals; the mixture and separation of the good and the bad; various elements of the last judgment of Christ; and the timing of the last day. All of this amounts to what God has revealed in scripture and commanded his bishops to preach concerning the path of salvation. This is a contextualized study of the sermons, in which Augustine is portrayed as more than a thinker or a theologian. He is also a bishop, a shepherd of souls and a watchman over his flock, ever vigilant against the real dangers – both internal and external – that jeopardize the eternal welfare of his people. The same teachings are therefore applied differently in different sermons, which are distinct in their time, place, and audience. The content and style of Augustine’s preaching depends on his perception of what his listeners most need to hear., Degree awarded: Ph.D. Greek and Latin. The Catholic University of America
Military Family Functioning Post 9/11
Background: Military families Post-9/11 have been taxed by lengthy and frequent deployments and physical and mental injuries. Despite the clear importance of understanding the impact of deployments and service member injuries on family relationships, there are substantial gaps in the limited research literature on post 9/11 military families. Objective: To provide an in-depth understanding of the impact of military life on family functioning through descriptive accounts and comparing experiences of post 9/11 military families from normative active duty (AD) and non-normative wounded warrior (WW) perspectives. Method: To gain detailed insight and understanding into participants' thinking and perceptions of military life, four semi-structured focus groups were conducted with two groups of spouses, 13 AD and 12 WW. Interpretative phenomenological analysis was utilized to construct meaning from the information gathered in the focus groups. This was accomplished by categorizing the data into themes identified from participants' descriptions of the issues, events, and expressed feelings. Results: A number of themes emerged from the detailed narrative accounts of the two groups. Superordinate themes for AD spouses include the general military experience and deployments with themes related to support, children and identity. Superordinate theme for WW spouses included the impact of the injury with themes related to the medical experience, impact on children, support, and identity. Conclusions: Consistent with previous research, normative military experiences for AD families (frequent moves, being away from family, and the deployment cycle) strain the marriage, negatively affect the wellbeing of the non-military spouse, and impact children's adjustment. Also in line with past research, spouses in WW families exhibit feelings of guilt, social isolation, confusion, lower marital quality, negative impact on wellbeing, role strain, and caregiver burden in relation to the non-normative experience of war-related injuries. However, findings from this research demonstrate that both groups experience growth in phases in relation to their adaptation to military life; experiencing anger, grief, letting go, and acceptance. Furthermore, despite a number of challenging experiences, flexibility and a positive mental outlook contribute to success in a military marriage and lead to resilience for spouses in general, and those navigating the terrain of war-related injuries., Degree awarded: Ph.D. Psychology. The Catholic University of America
Reclaiming Hans Urs von Balthasar's Theodramatic Eschatology: Revisions from Jacques Maritain, Joseph Ratzinger, and Bernard Lonergan
This dissertation takes up the problem of Hans Urs von Balthasar's purported resolution to the aporia between God's infinite love and the reality of eternal damnation, namely, his trinitarian theodramatic eschatology. Instead of being preoccupied with interpretive questions, I examine the logical rigor and precision of Balthasar's arguments, principally in his Theodramatik, in comparison to that found in Maritain, Ratzinger, Lonergan, and other Thomists. I also evaluate the arguments of some who have already criticized his work from one angle or another. Thorough analysis of Balthasar's fundamental claims yields the conclusion that his theological anthropology, in particular, his understanding of the grace-freedom dynamic, is lacking and detrimentally affects his eschatology. His eschatological position that all men may in fact be saved is a result, primarily, of the simplistic view of grace and freedom that he unwittingly assumes. His theology of the descent, while at points rhetorically excessive, represents a legitimate development and does not necessarily entail universalism. Furthermore, while his trinitarian theory at times borders on the mythological (thanks to Adrienne von Speyr), his understanding of divine suffering may be appropriated in dialogue with Jacques Maritain and Joseph Ratzinger, with whom he is closely allied on many fronts. But in order to reclaim Balthasar's theodramatic approach from its tendency toward universalism (following Karl Barth), attention must be given to the twentieth century developments in the Catholic theology of grace, attention which he did not wish to pay to such purportedly "neo-scholastic" debates. The growing consensus that has been emerging, at least among Thomists, concerning the question of the divine permission of moral evil, fills a lacuna in Balthasar's project, derailing it from the path of universalism and setting it on track toward a more robust theological anthropology. A critique of his monumental work along these lines yields a more balanced approach to the task of reconciling God's infinite mercy with the persistent reality of moral evil. The unbounded power of God's grace is not undermined by recognizing the possibility of created freedom to refuse His glory definitively; rather, the natural integrity of human freedom is slighted by an over-emphatic anti-Pelagian view of grace as either inherently irresistible or predetermined to be impotent. The intrinsic efficacy of divine grace and the natural integrity of human freedom together must be affirmed. The eschatological consequence of such a moderate view is precisely a more modest proposal for how in the end God may be "omnia in omnibus" (1 Cor 15:28)., Degree awarded: Ph.D. Historical Systematic Theology. The Catholic University of America

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