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Statistical Methods for Joint Outcome Modeling and Dynamic Assessment of Recurrent Events
No full textRecurrent event data frequently arise in clinical studies where individuals experience repeated, possibly related, events over time. These data are often accompanied by sparse and irregular longitudinal measurements, creating challenges for traditional joint modeling approaches that struggle to account for time-dependent associations and within-subject correlations. We propose FRAILTY (Functional Regression with AutoRegressIve fraiLTY), a novel two-step framework that integrates functional principal component analysis (PACE) with a dynamic frailty model featuring autoregressive structure. FRAILTY accommodates both scalar and functional predictors and captures within-subject dependence across recurrent events. To further extend its utility, we develop a multivariate joint modeling framework that simultaneously characterizes multiple types of recurrent events along with a terminal event, leveraging a shared structured frailty component. This extension enables more flexible modeling of interdependencies between different recurrent processes and the risk of terminal events, particularly in the presence of time-varying covariate effects derived from longitudinal trajectories. Estimation is carried out via an EM algorithm combined with Gaussian quadrature for efficient likelihood maximization under informative censoring. Simulation studies demonstrate that FRAILTY and its multivariate extension outperform existing methods in estimation accuracy, robustness under data sparsity, and predictive performance. Applications to the SPRINT and MSTONE studies illustrate its capacity to uncover clinically relevant patterns in complex event histories. To assess predictive performance, we also develop a weighted concordance index for recurrent event data subject to induced dependent censoring. Using inverse censoring probability weighting, our estimator reduces bias and mean squared error compared to existing C-index estimators. Application to the MSTONE dataset illustrates its utility in real-world predictive evaluation
Portfolio Dynamics and the Supply of Safe Securities
No full textI study dynamic portfolio rebalancing in Collateralized Loan Obligations (CLOs) by developing an industry equilibrium model of nonbank lending, in which CLOs and loan funds arise endogenously in response to a premium for safe securities. When loans deteriorate after issuance, CLOs rebalance their portfolios to maintain collateral quality, which protects senior tranches at the expense of equity investors. This self-healing mechanism lowers CLOs\u27 ex-ante funding costs by enabling the issuance of larger safe tranches. As more lenders operate CLOs, their portfolio rebalancing generates greater non-fundamental price pressures, incentivizing other lenders to operate loan funds. Overall, portfolio dynamics facilitate risk sharing across nonbank lenders and increase both total lending and the supply of safe securities relative to static portfolios
Oxytocin\u27s Role in Feelings of Social Connection and Loneliness
Full text linkThis study investigated the role of oxytocin (OT) in feelings of social connectedness. Healthy male and female participants (N=138) were exposed to a task designed to elicit feelings of social connectedness to close others (i.e., the Social Connection Task); participants’ salivary OT levels were measured in response to this task. Using ecological momentary assessment (EMA), data were collected on participants’ feelings of social connectedness in daily life. Results from the current study showed that, among male participants, OT levels decreased in response to the Social Connection Task, while no change in OT was observed among female participants. OT reactivity to the task (indexed as the area under the curve with respect to increase; AUCi) was not significantly associated with levels of trait loneliness. EMA data, however, revealed a significant association between OT reactivity and feelings of social connectedness in daily life – specifically among male participants. Overall, participants reported feeling more socially connected when they were around others compared to when they were alone. For male participants, however, OT reactivity played a significant role in the strength of this effect. Those with higher levels of OT reactivity experienced a more pronounced increase in social connectedness when around others, compared to when they were alone. In other words, the impact of being with others (versus being alone) was stronger for male participants with higher levels of OT reactivity. For female participants, on the other hand, OT reactivity did not significantly impact feelings of social connectedness when around others (versus when alone). These results provide preliminary evidence for theoretical models implicating the OT system in individuals’ social sensitivity to social experiences
Farming with data: tracing critical tensions using data science for food justice
Full text linkIn this manuscript, we explore the intersection of artificial intelligence (AI) and equitable learning in higher education, focusing on data science as a subset of AI and social justice as the core theme of equity. Our investigation sheds light on the nuanced tensions inherent in employing data science for social justice. Rooted in situated perspectives of learning and consequential learning, our study employs an instrumental case-study methodology and analysis techniques from interaction and conversation analysis. Collaborating with three undergraduate students and an urban farm, the students used data science practices to highlight inequities surrounding food justice and access to food. Our findings reveal three key tensions: (1) the undergraduates\u27 discourse on simplicity versus complexity in utilizing data science for social justice, (2) the challenges of balancing data science with social justice imperatives, and (3) the successful application of data science by the students in their food justice project, culminating in a presentation of their findings to the farm\u27s director. We conclude by discussing implications for research and the use of data science in social justice project
Shutting Down the Supply Chain Pipeline of Counterfeit Goods Running From Alibaba to Amazon
Full text linkAn immense supply chain pipeline constantly funnels millions of counterfeit goods from Alibaba’s e-commerce sites in China to third party sellers who sell these goods on Amazon to U.S. consumers. Amazon has acknowledged that it has a problem with counterfeits on its e-commerce sites, but its current responses to counterfeiting are primarily performative and intended to pacify disgruntled brand owners and frustrated consumers. Amazon’s responses will likely have little or no effect on counterfeits on its websites. This Article sets forth a direct and straightforward method for shutting down or seriously disrupting this pipeline based on using China’s existing laws. This method involves using verification methods required by China’s laws to ensure that only lawful and legitimate businesses, not counterfeiters, can open online accounts on Alibaba and other Chinese e-commerce platforms. Unless these steps are taken, counterfeits sold on Amazon and other e-commerce platforms will likely continue to plague brand owners, consumers, and the general public in the United States for the foreseeable future
AI-Powered Unobtrusive Sensing for Advancing Social Good
No full textSmart devices are becoming increasingly integrated into our daily lives, offering convenience and immersive experiences. However, the existing authentication methods for these devices are insecure and vulnerable to various attacks. For example, traditional biometric authentication methods (such as Face ID, fingerprint, and hand biometrics) can be easily forged using advanced 3D technologies and leveraged for replay attacks. Beyond security, smart devices also pose significant safety risks. For example, while smartphones enable easy communication, the constant need to check notifications distracts drivers, creating dangerous driving conditions. Moreover, although smart devices like smartphones and smartwatches are widely used in healthcare, they often require active user input, which can limit their effectiveness in continuous monitoring scenarios. While Artificial Intelligence (AI) has made significant contributions across various societal domains, effectively applying it to solve real-world problems for the greater social good remains a challenge. My research focuses on combining the power of AI with unobtrusive sensing technologies to address this gap. Specifically, I aim to enhance security, improve safety, and make smart devices more seamless and user-friendly in healthcare applications
Drip Hoses and Discipleship: Rethinking the Future of Theological Education with Justo González
No full textIn early February 2020 I spent a day with Justo González at his home in Decatur, Georgia, to discuss the future of theological education. The following piece showcases the disciplined imagination of one of the greatest church historians of our generation as he explains how drip hoses, worship, baptism, online learning, and more could guide the next generation of theological educators. In what follows, the reader will get a sense for why González thinks theological education is in a place of promise rather than peril.
A principios de febrero de 2020, pasé un día con Justo González en su casa en Decatur, en Georgia (USA), para hablar sobre el futuro de la educación teológica. El siguiente articulo muestra la disciplinada imaginación de uno de los más grandes historiadores de la iglesia de nuestra generación mientras explica cómo las mangueras de irrigación, la adoración, el bautismo, el aprendizaje en línea y más podrían guiar a la próxima generación de educadores teológicos. En lo que sigue, el lector tendrá una idea de por qué González cree que la condición de la educación teológica es más prometedora que peligrosa
Recollections of a Tejana Life
No full textThis thesis encompasses the life of a young woman navigating life in Texas through various political and social barriers. My interdisciplinary practice analyzes the historical context of Mexicans in Texas from its Revolutionary period into current injustices. Through fiber, printmaking, and photography I create a visual diary to illustrate what the political has made personal. These works display the beauty of Tejano culture, but also the power struggles that threaten communities I care for, as well as my own existence that persists against far-right wing agendas.
Current politics and government leadership in Texas have inspired me to make artwork calling out ongoing xenophobia and the whitewashing of a state that has deep Mexican lineage and once belonged to my people despite the pressure to push us out and silence us. It is crucial for me to vocalize issues many Tejanos face today.
In a society plagued by capitalism, misogyny, xenophobia, and governmental overreach, I use photography, silkscreen prints, sewing, and hand embroidered work to combat harmful rhetoric and propaganda. I address my choices in materiality and how the topics such as immigration, labor, reproductive justice, and environmentalism have been addressed.
The body of work expresses the experiences I face as a Gen-Z Tejana woman living in the 21st century and in a country on the brink of a cultural collapse. Recollections of a Tejana Life recognizes Texas history’s role in shaping the state today in addition to emerging threats to Mexicans, women, and everyday Texans. My art affirms Tejanos/as belongingness in visual culture and historical narratives that make Texas vibrant, diverse, and a home worth saving
The Tenth Anniversary of Marriage Equality: How Traditional Marriage Law Led to Constitutional Protection for Same-Sex Marriage
No full textThis essay explores how the history of interstate marriage recognition law was central to the Supreme Court’s recognition of constitutional protection for the right of same-sex couples to marry. Prior to the 1990s, there were essentially no laws on same-sex marriage in the United States. That changed in the 1990s, when the Hawaii Supreme Court issued a ruling in Baehr v. Lewin that made authorization of same-sex marriage seem inevitable in that state. The threat fueled the adoption first of the federal Defense of Marriage Act (DOMA) in 1996 and then mini-DOMAs in most states. Those laws were broad and unprecedented. DOMA singled out one type of marriage for nonrecognition under any federal law or program, while most federal laws do not provide definitions of marriage, even where marital status is highly relevant such as in eligibility for spousal Social Security benefits. Rather, Congress has traditionally deferred to state law determinations of personal status when applying federal laws. State DOMAs prohibited the celebration of same-sex marriages within their borders and recognition of those celebrated elsewhere. These laws were also unprecedented in that they barred interstate recognition of all same-sex marriages without any consideration of the common-law rules that usually drove such determinations. The departures from the usual approach to federal-state and interstate marriage recognition provided a doctrinal hook for constitutional protection. Although the Supreme Court recognized the right of same-sex couples to marry in Obergefell v. Hodges in 2015, the key inroad was its decision in Windsor v. United States, two years earlier. In Windsor, the Court struck down the federal law provision of DOMA based on the idea that discrimination of an unusual character raises the specter of animus—and animus cannot be the sole justification for a valid governmental action, even when the targeted group has not been recognized as a suspect or quasi-suspect class. The same argument was then used to attack the state DOMAs. The “discrimination of an unusual character” was the legislatures’ blunt and categorical non-recognition of same-sex marriages, despite strong histories in most states of granting recognition to marriages that were validly celebrated elsewhere despite strong opposition within the state. The opponents of same-sex marriage unwittingly undermined their own cause by enacting such unprecedented and unforgiving nonrecognition laws