UCLA

This dissertation investigates the historical development of Greek syllabification from Mycenaean through the Archaic first-millennium dialects, with particular attention to its implications for the reconstruction of Proto-Indo-European (PIE) syllable structure. It develops a unified account of Greek syllabification by integrating linguistic, orthographic, metrical, and philological evidence within an Optimality-Theoretic (OT) framework.The study draws primarily on Mycenaean and Homeric Greek, the earliest attested stages of the language, while also incorporating comparative Indo-European evidence where relevant. Four complementary sources of evidence are examined: sound changes and synchronic phonological processes sensitive to syllable structure; Linear B orthography and inscriptional practices; metrical evidence from Homeric poetry; and observations preserved in the ancient grammatical tradition. Philological analysis and phonological modeling are employed jointly to reassess longstanding problems concerning Greek and PIE syllable structure.The dissertation reaches four main conclusions. First, a comprehensive reexamination of the evidence shows that Liquid Metathesis was not a productive feature of Mycenaean phonology. Second, the directionality of sonorant vocalization in Mycenaean is demonstrated to be governed by syllable well-formedness rather than occurring in free variation, supporting an analysis in terms of vowel epenthesis conditioned by syllabification. Third, Linear B orthography is shown to be compatible with an independently established account of Greek syllable structure based on cluster heterosyllabicity, allowing both regular spelling conventions and apparent exceptions to be derived within an OT model. Fourth, the comparison between Mycenaean and Homeric Greek indicates that the Greek linking vowel -o- originated as a phonologically conditioned repair strategy before being reanalyzed as a stem-level morphological process. A Stratal OT analysis accounts for this development and relates it to other changes in Greek syllable structure between the second and first millennia BCE.Taken together, these findings reconcile linguistic and orthographic evidence that has traditionally been regarded as contradictory and support a reconstruction of Greek syllable structure based on cluster heterosyllabicity. They further indicate that Mycenaean preserves several properties of PIE syllable structure that predate innovations attested in the first millennium BCE, demonstrating that linguistic, orthographic, metrical, and philological evidence can be integrated within a single account of the early history of Greek phonology.

Proton-exchange-membrane fuel cells (PEMFCs) directly convert chemical energy into electricity with water as the only byproduct, providing a promising pathway toward a zero-emission future. Their commercial success has been demonstrated in light-duty vehicles (LDVs) exemplified by the Toyota Mirai. Compared with battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs) offer distinct advantages for heavy-duty vehicles (HDVs), including shorter refueling time, higher payload capacity, and reduced weight penalty. However, the harsh operating conditions and prolonged service life of HDVs impose stringent requirements on PEMFC durability, while the increasing demand for Pt catalyst calls for reduced Pt utilization and scalable manufacturing. Therefore, developing highly durable, cost-effective, and industrially scalable Pt-based electrocatalysts is critical for the widespread commercialization of PEMFCs in heavy-duty transportation. Chapter 2 presents a graphene-nanopocket protected Pt nanoparticle (Pt@Gnp) that enhances durability by suppressing Pt dissolution, particle coalescence, and ionomer poisoning during accelerated-stress-tests (ASTs). The resulting fuel cell exhibits only 1.1% rated power loss after 90,000 AST cycles, corresponding to a projected lifetime exceeding 200,000 h, more than seven times the U.S. Department of Energy (DOE) ultimate target for heavy-duty applications (30,000 h). Chapter 3 introduces a unique design of Pt nanoparticles embedded with cerium oxide clusters (CeOx@Pt), in which strong CeOx-Pt interactions suppress Pt dissolution, migration, and particle growth. The catalyst satisfies the DOE heavy-duty end-of-life (EOL) performance target of 1.07 A/cm2 at 0.7 V after 90,000 AST cycles at a low total-PGM-loading of approximately 0.1 mgPGM/cm2, reducing Pt cost by 70% relative to the DOE Million-Mile Fuel Cell Truck (M2FCT) Consortium target. Chapter 4 develops a laser ablation-based synthesis strategy for Pt nanocatalysts that increases production throughput by 10-folds compared with conventional wet-chemical synthesis. The rapid heating and cooling inherent to laser ablation also create metastable nanotwinned structures that enhance catalyst durability during fuel cell operation. Overall, the work presented in this dissertation demonstrates complementary catalyst design and synthesis strategies that simultaneously improve durability, reduce Pt utilization, and enable scalable catalyst manufacturing. These advances provide practical pathways toward the commercialization of PEMFCs for heavy-duty transportation and contribute to the broader transition toward sustainable, zero-emission transportation.

Understanding emotion dynamics is important in order to ascertain transdiagnostic mechanisms underlying anxiety and mood disorders. Emotional inertia, the stability of emotion over time, and emotion network density, a measure of the interconnectedness of emotions, both represent the persistence of emotions over time. Previous literature suggests that emotional persistence, particularly of negative emotions, is related to depression, anxiety, and difficulty with emotion regulation. However, this research is limited in that studies examining idiographic network density, longitudinal relationships, and transdiagnostic, continuous, or objective outcome measures are scarce. Additionally, existing studies present mixed findings on the implications of positive emotional persistence. This dissertation contains three studies designed to address these shortcomings and examine relationships among emotional persistence and transdiagnostic psychological well-being in adults with moderate-to-severe depression, with the ultimate goal of illuminating mechanisms underlying anxiety and depressive disorders such that current treatments may be improved.Study 1 examined both cross-sectional and longitudinal relationships among emotional inertia, emotion network density, and self-reported well-being. Inertia and density were both calculated using self-reported affect ratings from ecological momentary assessment (EMA) surveys administered five times per day in two eight-day epochs. Inertia and density were calculated separately for negative and positive affect. Positive contemporaneous network density was positively associated with well-being six weeks later. Positive emotional inertia was inversely associated with well-being six weeks later. Neither negative inertia nor negative network density was associated with subsequent well-being, and emotional persistence was not related to concurrent reports of well-being.Study 2 examined cross-sectional associations between emotional persistence and heart-rate variability. Inertia and density were again calculated using EMA surveys, this time from three eight-day epochs. Heart-rate variability was measured via Apple Watch both during the day and at bedrest throughout all three epochs. Negative contemporaneous network density was inversely associated with both median daytime and median bedrest heart-rate variability. That is, participants with more densely connected negative emotions demonstrated lower heart-rate variability. Positive emotional persistence was not related to heart-rate variability.Study 3 examined relationships between emotional persistence and linguistic indicators of well-being. Measures of emotional persistence were the same as in Study 2. Natural linguistic processing was used to analyze transcripts of a ten-minute structured interview where participants answered questions about their previous week. Probability of both positive and negative sentiment was obtained using natural linguistic processing, and tendency towards positive sentiment was operationalized as the participants’ average difference between probability of positive and negative sentiment. Tendency towards positive sentiment was examined in relation to positive and negative emotional persistence. No metric of emotional persistence was associated with linguistic sentiment. However, participants who reported higher levels of average positive affect via EMA demonstrated higher tendency towards positive sentiment during the interview.Taken together, these findings provide insight into the implications of positive and negative emotional persistence. Emotional inertia and emotion network density seem to represent different, and at times opposing, presentations of emotional persistence. Broadly, this dissertation supports the literature suggesting that denser negative emotion networks are maladaptive and denser positive emotions reflect better psychological well-being. Contrasting results for negative and positive emotional persistence suggest that persistence of differently valenced emotions may relate to different components of psychological and physiological well-being. This study also highlights the methodological challenges of using objective measures of emotional functioning such as natural linguistic processing. Future research should continue to address these methodological limitations and investigate the mechanisms underlying the relationship between emotional persistence and psychological well-being to inform clinical interventions.

About 2.7% of the 187 years spent researching ozone are encapsulated in this dissertation. The main goal of the research conducted was to improve dealkenylation, an emerging organic chemistry method for synthesis through C(sp3)–C(sp2) bond scission. The first generation of dealkenylation required the use of ozone to generate a high-energy peroxide intermediate which enabled radical cascades to break bonds and create new, valuable products. A second generation was developed through this work to bypass the ozone requirement and thereby diversify the chemical space available to dealkenylation. Not only did this second generation solve issues regarding incompatibilities of alkenes with ozone, but also it broadened the products available after radical functionalization. Further research into the ozonolysis reaction led to the development of a predictive tool to quantify the dealkenylation peroxide intermediate and provide a more complete understanding of the overall transformation. Additionally, two new transformations involving ozone were uncovered. The first applies dealkenylation to cycloalkanones to access their 1-carbon deleted analoges. Samarium iodide was the key to both initiate the radical cascade and to reform the ring after carbon excision. The second is the ozonolysis of a C–C sigma-bond. The bridging C–C sigma-bond of a bicyclo[1.1.0]butane and a bicyclo[2.1.0]pentane was activated to enable radical addition of ozone. Computational studies predicted two mechanistic pathways, of which the major supports the formation of a 1,2,3-trioxane, which has never been realized in a flask. Chapters one, two, and four originate from review articles that provide background on the field of peroxide chemistry (chapter one), and present day dealkenylation (chapter two and chapter four). Chapters two and four are each included with permission from the first authors. Chapter three introduces the second generation of ozone-free dealkenylation. Chapter five offers solutions to enable ozonation of some compound classes previously thought to be incompatible. Chapter six discusses the experimental work completed to generate the dataset for the machine learning model to quantify ozonolysis products. Chapter seven provides a proof of concept for the dealkenylative ring contraction strategy. Finally, chapter eight reveals the first ozonolysis of C–C sigma-bonds. Overall, this research advances the dealkenylation methodology, expanding into ozone-free techniques, predictive tools, and new atom-editing strategies. This work culminates with the discovery of C–C sigma-bond ozonolysis.

Accumulating evidence suggests a neuroinflammatory subtype of psychotic illness. Magnetic resonance spectroscopy (MRS) can indirectly assess neuroinflammation via measurements of neurometabolite biomarkers: myo-inositol (mI) for glia; choline (Cho) for membrane turnover; creatine (Cr) for energy metabolism; N-acetylaspartate (NAA) for neural integrity; and glutamate and glutamine (Glx) for glutaminergic neurotransmission. Previous MRS studies of psychoses show mixed findings, which could reflect most: 1) only comparing metabolite levels between cases and controls rather than also examining associations with symptoms and cognitive deficits; 2) intermixing different psychoses (e.g., schizophrenia vs. affective psychoses) rather than stratifying them, a common research practice that echoes transdiagnostic approaches like NIMH’s Research Domain Criteria (RDoC), which posits similar cellular pathologies across diagnostic categories for deficits with neurobehavioral functions. The present study used hippocampal proton magnetic resonance spectroscopic imaging (¹H-MRSI) and measured correlations of neurometabolite concentrations with MATRICS cognitive scores and symptom levels (five-factor PANSS and Hamilton Depression and Young Mania Scales) in 26 healthy, 22 non-psychotic affective, and 33 psychotic participants (including 20 schizophrenia and 13 affective psychosis). Despite similar metabolite levels across groups, affective psychosis showed a strong association between increased mI (glia) and worse attention (ρ=-.847, p=.016), and a moderate association between increased Cho (membrane turnover) and mania (ρ=.654, p=.015). In schizophrenia, elevated levels of PANSS activation (behavioral dyscontrol) factor were related to reductions in all neurometabolites (NAA, Cr, Cho, mI, Glx) (p’s<.05), robustly for mI (ρ=-.842, p=.0002). Between-group comparisons suggested distinct cellular abnormalities across diagnostic categories for social cognition and reasoning deficits, activation, and mood symptoms, but similar abnormalities for negative symptoms and PANSS autistic preoccupation (disorganized) factor. These findings suggest neuroinflammatory underpinnings for attention deficits and manic symptoms in affective psychosis patients with greater severity of these clinical features. Results in schizophrenia indicate a process causing widespread multisystem cellular deficits and substantial glial loss for patients with higher levels of activation. Both distinct and similar cellular pathologies were suggested for cognitive and symptom domains across psychotic vs. non-psychotic disorders and affective vs. non-affective psychoses. The differences support categorizing disorders and stratifying different psychoses in research rather than fully abandoning diagnostic labels for transdiagnostic approaches.

Boundaries and defects host localized interactions of the dynamic degrees of freedom and provide the certain conditions on the field at the location of them. In guage theories and gravity, the dynamics of the large gauge degrees of freedom is localized on the boundary and are best described within the covariant phase space formalism using the symplectic form and boundary action. When the gravitational effects are strong, these large gauge degrees of freedom dress the on-shell matter action, which can be described using Hamiltonian formulation by integrating out these edge modes. We present the two efficient methods of computing the symplectic form associated with the boundary degrees of freedom. We then consider the near-extremal charged black holes in 4d, where the gravitational effects are enhanced at low temperature and study the Hawking radiation at near-horizon AdS2 using the Hamiltonian formulation, with emphasis on comparing this to the JT gravity. Extending this perspective to study of defects, we develop a Lagrangian based method for computing the higher structure of non-invertible defects and compute the associators of the duality and triality defects in the 4d Maxwell theory. We then consider a family of codimension-1 non-conformal defects in the free non-compact boson theory and relate the two descriptions—localized interaction and discontinuous relations and study its scaling behavior and effects in spectrum.

Treatment engagement challenges are among the most persistent barriers to effective youth mental health treatment, with a substantial proportion of youth and families terminating services before achieving expected clinical gains (Becker & Chorpita, 2023). Despite growing recognition of the multidimensional, dynamic, and transactional nature of treatment engagement, relatively little is known about the within-session therapist behaviors that may occur in the context of and inadvertently contribute to engagement challenges. This dissertation examined therapist “missteps,” or inadvertent, less optimal, or noncollaborative therapist behaviors, across two studies using observational data from the Reaching Families Study, a multisite cluster-randomized trial focused on improving use of evidence to target low treatment engagement in publicly funded youth mental health settings (Chorpita et al., 2025). Study 1 sought to first understand how therapists misstep by examining the occurrence of missteps across several key contextual factors, including session composition, the recipient of the misstep, and the surrounding in-session therapist behaviors. Therapist missteps were prevalent, occurring in over half of recorded therapy sessions with an average of approximately 2.5 missteps per session. In family sessions, missteps were most frequently directed at the youth. Advice-giving emerged as the most prevalent type of therapist misstep to occur across all session types. Descriptively, approximately 38.1% of observed missteps occurred following another misstep occurrence (10.6%) or in the absence of an identifiable evidence-based technique (27.5%). These findings suggest that missteps may be a common occurrence when delivering care, particularly in the context of engagement challenges, and may be more vulnerable to occur during unstructured or uncertain moments in a session. The first study also sought to examine when therapists may misstep by examining associations between misstep occurrences and factors related to therapist preparedness. Findings suggest that neither the timing of supervision relative to treatment nor the presence and quality of a treatment plan established for the session were credibly associated with total misstep frequency. These findings converge with later findings in Study 2, which indicated that the presence of a treatment plan did not appear to moderate the relationship between misstep frequency and average practice extensiveness, an aggregate indicator of the overall quality of treatment delivered in the session. Together, these findings suggest that identifying what to do in the next session alone may not be sufficient in supporting therapists from engaging in inadvertent missteps. However, provision of comprehensive, coordinated decision-making supports for the detection, identification, and targeted intervention of engagement challenges (i.e., the Coordinated Knowledge System, CKS) was associated with substantially lower expected misstep rates in Study 1. This robust effect remained in exploratory analyses even after accounting for the therapist’s optimal practice quality in the session (i.e., the maximum practice extensiveness across all practices delivered in the session). Study 2 extended these findings by examining what happens in the therapy session when missteps occur. Misstep frequency was credibly associated (i.e., in Bayesian estimation, displaying sufficient evidence that the effect is real and in a consistent direction given the posterior distribution of the parameter) with the therapist’s overall treatment quality for the session (i.e., average practice extensiveness) in the originally proposed analyses, however, the credible interval marginally excluded zero and should be interpreted with caution. Exploratory analyses using the therapist’s maximum practice extensiveness revealed a credible association with misstep occurrences, in which increases in the therapist’s practice quality were associated with decreases in misstep occurrences in the session. Misstep occurrences were also credibly associated with a modest decrease in session-level engagement for both youth and caregivers, after accounting for baseline engagement challenges, maximum practice extensiveness, site, and study condition. Variance decomposition of youth and caregiver session-level engagement also revealed that although the therapist level accounted for significant variance (23.0%) in youth session engagement, caregiver session engagement was more organized at the client level (22.3%). Together, these findings reinforce the conceptualization of engagement as a dynamic, state-like phenomenon that is co-constructed within the session rather than trait-like features of clients, and position therapist behaviors as an important component of session-to-session engagement. Overall, these studies found that therapist missteps occur routinely in youth publicly funded mental health settings and are associated with measurable changes in session-level engagement. Additionally, provision of coordinated clinical supports aimed at supporting therapists with navigating well-documented “blind curves” when delivering care in complex contexts, as well as extensive delivery of an evidence-based practice, were associated with expected decreases in misstep occurrences. These findings continue to support the theoretical framing of therapist missteps as predictable features of treatment delivery and center a locus of intervention that shifts away from the therapist’s intrinsic traits and qualities and towards scaffolding flexible, matched, and coordinated clinical decision-making supports to improve care for youth and families.

Digital anti-Black girlhood is a complex form of multi-layered oppression enacted in digital spaces deeply rooted in sexist and racist stereotypes specifically targeting adolescent Black girls. Black teenage girls are subjected to experiencing digital anti-Black girlhood through posts, comments, and direct messages from peers, adults, and strangers, which may negatively shape their wellness, self-perception, and self-esteem. Although growing research focuses on online racism, there is minimal empirical research investigating gendered racism intersectionally on social media experienced by Black girls qualitatively. Thus, it is imperative to explore gendered racism in online spaces. This qualitative study employed constructivist grounded theory, photovoice, and Black Girl Youth Participatory Action Research (BGYPAR) to explore their experiences and implications of racialized sexism on social media. One-on-one virtual semi-structured interviews were conducted with a diverse sample of N=41 Black girls and non-binary individuals in the U.S., ages 14-18. Data was analyzed inductively via initial and post- coding memos, open coding, focused coding, analytic memos, and team discussions. Digital anti-Black girlhood is detrimental to the well-being and development of Black girls. Identifying how racialized sexism emerges for teenage Black girls is an initial step to dismantling it. Social work practitioners and scholars can combat gendered racism in digital spaces by developing interventions, policies, and educating youth and adults about this form of online violence. Furthermore, social workers can develop tools to support youth in pathways to socio-emotionally responding to and processing distress stemming from digital anti-Black girlhood.

Background: Depression is highly prevalent among Korean Americans, and stigma continues to contribute to delayed help-seeking and persistent symptoms. Help-seeking behaviors are often influenced by family members and social networks. Culturally tailored, evidence-based interventions targeting these groups remain limited. Objectives: This quality improvement project aimed to evaluate the impact of a single-session, culturally tailored, Korean-language psychoeducation program in reducing depression stigma among Korean American caregivers, family members, and friends of individuals with depression. Methods: The quality improvement project used a one-group pretest–posttest design. The psychoeducational program was delivered across four cohorts, with two cohorts participating in in-person sessions and two cohorts participating in virtual sessions. Korean American adults aged 18 years and older who self-identified as caregivers, family members, or friends of someone with depression were invited to participate through a Korean church in Los Angeles. Participant demographic data included self-reported history of depression, with 35.5% of participants reporting a personal history of depression. The 90-minute session included education on depression and culturally relevant myths, supportive communication practice, and small-group discussion. Depression stigma was measured using the Depression Stigma Scale (DSS; personal and perceived subscales). Pre–post changes in DSS scores were analyzed with paired t tests. Results: Personal stigma scores decreased following the intervention (mean difference = 6.6, SD = 4.4, p < .001, Cohen's d = 1.5), and perceived stigma scores also showed a reduction (mean difference = 3.2, SD = 6.6, p = .012, Cohen's d = 0.5). Conclusion: The culturally tailored psychoeducational program was associated with reductions in both personal and perceived depression stigma among the social networks of Korean Americans with depression. The findings suggest that a brief, community-based, and culturally relevant approach may offer a feasible approach to addressing stigma-related attitudes, which has been identified as one contributor to delayed help-seeking among Korean Americans. The initial results support the importance of future initiatives with larger samples and longer follow-up to assess whether observed changes are sustained and whether the program can be implemented successfully in other community settings.

Wetlands are the largest natural contributor of methane, a potent greenhouse gas, to the atmosphere. The anaerobic oxidation of methane (AOM) is a major sink to methane in coastal wetland sediments and is typically sulfate-dependent. Anthropogenic activity may feed nitrogen pollution into nearby coastal wetlands yet its effect on AOM is poorly understood. This study utilized isotope-labeling experiments with in vitro sediment (0–3 cm) slurry incubations to identify how nitrate in nitrogen pollution may affect coastal wetland AOM. Nitrate generally suppressed AOM, but its effect was pathway-specific: while sulfate-dependent AOM was suppressed, nitrate/nitrite and sulfate-independent AOM (e.g. iron and humics substances-dependent AOM) was not. Overall, nitrate/nitrite and sulfate-independent AOM potentially accounted for over half of AOM across the nitrate-amended incubations. Contrary to prior assumptions that sulfate-dependent AOM dominates in coastal wetland sediments, these findings suggest that nitrate pollution may shift dominant AOM pathways to nitrate/nitrite and sulfate-independent AOM.