Mixed-Effects Location-Scale Models for Conditionally Normally Distributed Repeated-Measures Data

Hypotheses about psychological processes are most frequently dedicated to individual mean differences, but individual differences in variability are likely to be important as well. The mixed-effects location-scale model estimates individual differences in both mean level and variability in a single model, and represents an important advance in testing variability-related hypotheses. However, the mixed-effects location-scale model remains relatively novel to empirical scientists as statistical software is often handicapped by more complex models and a paucity of methodological studies exist examining the statistical properties of this model. This dissertation investigates the mixed-effects location-scale model through the development of open-source software for its estimation and through simulation and empirical studies. First, the theoretical framework for the mixed-effects location-scale model is presented followed by a description of the Metropolis-Hastings algorithm developed to estimate this model. Then, two simulation studies are presented evaluating the power to detect and predict individual differences in variability as well as identify the consequences of model misspecification. Finally, results of an empirical analysis examining individual differences in mean level and variability of unstructured movements from a sample of older adults with and without probable mild Alzheimer’s disease is presented. Results of the power investigation simulation study indicated that the power to detect the scale-model random intercept variance and the effect of an individual-level predictor of residual variability increased with greater numbers of individuals and occasions, and that failing to detect the scale-model random intercept variance essentially precluded the detection of systematically varying fixed effects for an individual-level predictor of residual heterogeneity. Results of the misspecification simulation study indicated that misspecifying the location model and/or scale model for the residual variance had consequences only for fixed and random effects on the same side of the model. Finally, results of the empirical data analysis indicated individuals with probable mild Alzheimer’s disease averaged less movement compared to healthy individuals, but did not differ in the variability of their unstructured movements. In sum, this dissertation provides information useful to empirical scientists as they progress from study design through analysis, interpretation, and reporting for publication. Advisors: Lesa Hoffman & Jonathan Templi

China: Do the Uighurs represent a serious threat?

The People’s Republic of China’s (PRC) utilization of harsh ethnic control policies coupled with extreme and violent enforcement by the People’s Armed Police (PAP) will likely drive the Uighurs to become a security threat to the PRC and disrupt international relationships. The Uighurs do not currently constitute a security threat to the PRC based on their limited connection to terrorist organizations and attacks. Due to several underlying factors, the Uighurs represent a political concern to the PRC and the conflict between the PRC and the Uighurs is fueled by ethnic tensions. Ongoing security operations in the Uighurs’ home province of Xinjiang exacerbate tensions as the PAP enforce harsh ethnic control policies. As the international community is becoming increasingly aware of the situation in Xinjiang, the PRC has come under pressure to explain its actions. These underlying forces could plausibly drive the Uighurs to become a security threat to the PRC in the future

Ideology, Qualifications, and Covert Senate Obstruction of Federal Court Nominations

Scholars, policymakers, and journalists have bemoaned the emphasis on ideology over qualifications and party over performance in the judicial appointment process. Though, for years, the acrimony between the two parties and between the Senate and President remained limited to appointments to the United States Supreme Court, the modern era of judicial appointments has seen the so-called “appointments rigor mortis” spread throughout all levels of judicial appointments. A host of studies have examined the causes and consequences of the growing acrimony and obstruction of lower federal court appointments, but few rely on archival data and empirical evidence to examine the underlying friction between the parties and the two branches. In a unique study, the authors examine archival data to determine the conditions under which Senators obstruct judicial nominations to lower federal courts. More specifically, the authors examine one form of Senate obstruction — the blue slip — and find that Senators use their blue slips to block ideologically distant nominees as well as unqualified nominees. More importantly, however, the authors find that among nominations to federal circuit courts, Senators block highly qualified nominees who are ideologically distant from them just as often as they block unqualified nominees who are ideologically distant from them. That is, stellar qualifications do not appear to mitigate the negative effects of ideological distance. The fact that blue slips occur in private, away from public view, allows Senators to block nominees entirely on ideological grounds, without fear of individualized public retribution. Senators, in short, have taken an aggressive role in blocking highly qualified nominees who would otherwise make significant — but opposing — policy and who might one day become credible nominees to the Supreme Court were their nominations to move forward. By killing these nominations in the cradle, and outside the public view, Senators can block or delay the confirmation of judges with whom they disagree ideologically. The authors point out that policymakers and scholars who seek to reform the judicial appointment process must therefore be very clear about their goals. If a reform’s goal is to minimize the role of Senate ideology in the appointment process, then proposals that insulate the process from the public eye are likely to backfire. For, as the data show, Senators take advantage of insulation to achieve ideological goals. On the other hand, if a reform’s goal is to maximize the role of Senate ideology — perhaps to offset the President’s first mover advantage or to recognize and directly address the fact that courts are policymaking bodies — then proposals that insulate the process from the public eye are likely to accomplish that goal

Upending a Global Debate: An Empirical Analysis of the U.S. Supreme Court’s Use of Transnational Law to Interpret Domestic Doctrine,

Over the last ten years, judges, scholars, and policymakers have argued — quite vehemently at times — about whether U.S. courts should use transnational sources of law to interpret domestic legal doctrine. All eyes in this debate focus on the U.S. Supreme Court and its use, misuse, and alleged use of transnational law. And almost all the debates are normative. Some scholars and judges argue the Court is correct to use transnational law. Others believe to do so is constitutional apostacy. Still, the controversy seems to have generated more heat than light. Among the clamor can be found little empirical work on the conditions under which Supreme Court Justices actually use transnational law. Is it in fact the case that only liberal Justices employ transnational law — or do conservatives as well? In addition, there is little work on which countries Justices cite when they do use transnational law. Do they cherry pick whichever country works best in the given case, or is there a lower bound of plausibility when selecting countries to examine and cite? The authors provide the most systematic empirical exploration of the Court’s use of transnational law to date. Their results challenge conventional wisdom and prove to upend the existing debates over transnational law. The data show that Justices are more likely to reference transnational law when they exercise judicial review and when they overturn precedent, which likely explains much of the controversy around the practice. Importantly, the data show, further, that all Justices cite transnational law. Liberals cite transnational law when they render liberal decisions, and conservatives cite transnational law when they render conservative decisions. Liberals and conservatives alike employ such law because they are both ideologically conscious, strategic judicial actors who seek to support their decisions with as much persuasive material as possible. Finally, the results suggest that Justices cite countries with regard to their political and legal characteristics. They cite what the public would consider to be among the most legitimate countries across the globe. In other words, on the whole, Justices seem to borrow from countries most like the U.S. Whether these results are good or bad is unclear; what is clear, however, is that the normative debate over using transnational law must take a turn and address the authors’ findings

Collegiate Football Player Suffering from Non-Traumatic Hemoptysis

In volume 4, Issue 1 of the JSMAHS you will find Professional Research Abstracts, as well as Bachelor Student Research Abstracts and Case Reports. Thank you for viewing this 4th Annual OATA Special Editio

Bioluminescent Magnetic Nanoparticles as Potential Imaging Agents for Mammalian Spermatozoa

Background: Nanoparticles have emerged as key materials for developing applications in nanomedicine, nanobiotechnology, bioimaging and theranostics. Existing bioimaging technologies include bioluminescent resonance energy transfer-conjugated quantum dots (BRET-QDs). Despite the current use of BRET-QDs for bioimaging, there are strong concerns about QD nanocomposites containing cadmium which exhibits potential cellular toxicity. Results: In this study, bioluminescent composites comprised of magnetic nanoparticles and firefly luciferase (Photinus pyralis) are examined as potential light-emitting agents for imaging, detection, and tracking mammalian spermatozoa. Characterization was carried out using infrared spectroscopy, TEM and cryo-TEM imaging, and ζ-potential measurements to demonstrate the successful preparation of these nanocomposites. Binding interactions between the synthesized nanoparticles and spermatozoon were characterized using confocal and atomic/magnetic force microscopy. Bioluminescence imaging and UV–visible-NIR microscopy results showed light emission from sperm samples incubated with the firefly luciferase-modified nanoparticles. Therefore, these newly synthesized luciferase-modified magnetic nanoparticles show promise as substitutes for QD labeling, and can potentially also be used for in vivo manipulation and tracking, as well as MRI techniques. Conclusions: These preliminary data indicate that luciferase-magnetic nanoparticle composites can potentially be used for spermatozoa detection and imaging. Their magnetic properties add additional functionality to allow for manipulation, sorting, or tracking of cells using magnetic techniques