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Concerted Rattling-Induced Strong Anharmonicity and Phonon Coherence Lead to Ultralow Glasslike Thermal Conductivity in Tlagte
No full textOrdered crystalline compounds exhibiting ultralow and glass-like thermal conductivity are both fundamentally and technologically important, where phonon quasi-particles dominate their heat transport. Understanding the microscopic mechanisms that govern such unusual transport behavior is necessary to unravel the complex interplay of crystal structure, phonons, and collective excitations of these quasi-particles. Here, we use state-of-the-art first-principles calculations based on quantum density functional theory to investigate the origin of experimentally measured unusually low and glassy thermal conductivity in semiconducting TlAgTe that possesses disconnected chains of Tl atoms within its three-dimensional crystalline framework made up of distorted AgTe4 tetrahedra. Utilizing a unifying framework of anharmonic lattice dynamics theory that combine phonon self-energy induced frequency renormalization, particle-like Peierls (κPl ) and wave-like coherent (κCl ) thermal transport contributions including three and four-phonon scattering channels, we successfully explain the experimental results both in terms of magnitude and temperature dependence. Our analysis reveals that TlAgTe exhibits several localized phonon modes arising from concerted rattling-like vibration of Tl atoms, which show strong temperature dependence and enhanced four-phonon scattering rates that are dominated by Umklapp processes, suppressing κPl to ultralow values. The ensuing strong anharmonicity induced by local structural distortions, lone-pair electrons, and rattling-like vibrations of the heavy cations lead to a transition from particle-like behavior to wave-like tunneling characteristics of the phonon modes above 40 cm−1, contributing significantly to κCl which increases with temperature. Our analysis uncovers important structureproperty relationship, which may be used in designing of novel materials with tunable thermal conductivity
An Integrated Multivariate Econometric Modeling Framework for Risky Driving Behavior Related Crashes: Evaluating Crash Risk and Severity Across Zones
No full textRapid advancements in crash modeling have yet to fully integrate multiple behavior-driven crash types and their severity outcomes within a single, scalable framework, specially in a way that captures the sequential nature of these behaviors where one risky action may amplify another. This study proposed an integrated multivariate econometric framework to jointly model crash frequency and severity outcomes for three major behaviorally driven crash types: alcohol-related, distraction-related, and aggressive-driving-related crashes. Specifically, using Oregon\u27s 2022 census block group-level crash data, we propose an Integrated Multivariate Negative Binomial – Generalized Ordered Probit Fractional Split (IMNB–GOPFS) model to analyze these dimensions simultaneously while accounting for the sequential nature of the behavioral crash types. A comparison exercise in terms of model fit and predictive performance reveals the superior performance of the proposed framework over traditional non-integrated approaches, thus highlighting the existence and importance of capturing such interdependencies among behaviorally driven crashes. A brief elasticity assessment further highlights how several variables influence crash outcomes through both direct and behaviorally mediated impacts. Further, we apply the model results to identify high-risk zones and find that census block groups with increased truck exposure, greater rural and freeway road coverage, and larger variations in speed limits are consistently associated with elevated crash occurrences across multiple behavioral crash types. By focusing on the full spectrum of behavior-driven crash types and their severity outcomes, this study offers a comprehensive framework to support data-driven safety planning and proactive crash severity risk assessment at the planning level
The Birnirk to Thule Transition As Viewed from Radiocarbon and Tree-Ring Dating Within Two Adjacent Houses at Cape Espenberg, Northwest Alaska
No full textThe transformation of the Birnirk culture into the Thule culture is essential in reconstructing the emergence of modern Inuit across Alaska and the larger Bering Strait. To this end, two adjacent semi-subterranean houses of late Birnirk and early Thule affiliation, respectively, at the Rising Whale (KTZ-304) site at Cape Espenberg were recently excavated and dated by radiocarbon and tree-ring measurements. We present the Bayesian analysis of the resulting large series of dates, demonstrating the lack of contemporaneity between the two features: the Birnirk house was occupied in the late twelfth to early thirteenth centuries AD, whereas the occupation of the Thule house occurred in the second half of the thirteenth into the early fourteenth century. With the increased precision made possible by coupling dendrochronology with radiocarbon, our results place the Birnirk-Thule transition more that 200 years later than the generally accepted date of AD 1000. A transition in the second half of the thirteenth century has major implications for the timing of Thule presence along the coast of Alaska and for their migration into the Alaska interior. It aligns with a thirteenth-century migration into the western Canadian Arctic and farther east and a brief early or “initial” Thule period
Population Observations and Microhabitat Use of Isthmohyla Tica (anura: Hylidae) in San Ramón, Costa Rica
No full textIsthmohyla tica, the Tica Frog, is a critically endangered species endemic to Costa Rica and supposedly Panama that has only been seen in a few sites in recent decades. To aid in its conservation, we assessed the population status and microhabitat preferences of this frog in a section of the Danta stream at Rancho Alegre farm, San Ramón, Costa Rica. We conducted 18 nocturnal surveys and collected data on perch types, vegetation associations, stream characteristics, and environmental variables for each sighting of the Tica Frog. To identify potential microhabitat preferences, we compared these features between sites with or without frogs as well as between sites with juvenile or adult individuals. We recorded 13 individuals, comprising three juveniles and 10 adults. Nine adults were male and one female, with the disparity likely due to the conspicuous vocalizations of males. Juvenile and adult frogs occupied areas with similar stream widths (t = 0.91; p = 0.38). However, juveniles were found closer to the water (t = 5.14, p = 0.01) and adjacent to shallower areas of the stream compared to adults (t = 2.50, p = 0.03). Frogs predominantly perched on Piper sp. (30.7%) and on the upper surface of leaves (69.2%). The height at which the Tica Frog was recorded (0.1 to 2.2 m) was similar for both age groups (t = 0.86, p = 0.44). We did not find significant differences in canopy cover (average = 74.6%), diameter at breast height (≤ 3.14 cm), vegetation density (5.0 plants/m2), or plant richness (1–4 species) between juveniles and adults. Similarly, we did not observe differences in environmental variables between these groups. Furthermore, vegetation characteristics and environmental variables did not differ between sites with the Tica Frog and nearby sites without them. Our findings suggest that the measured variables do not significantly influence the microhabitat selection of the Tica Frog. This novel information on the population status and microhabitat use of I. tica is needed for the development of management strategies for the conservation of this critically endangered species
Orphan Basalts: Understanding the Origins of Unassigned Eastern Oregon Basalts
No full textFor more than a century, scientists have studied the geologic stratigraphy of eastern Oregon, which chronicles a rich history of volcanic activity spanning millions of years. Recent and ongoing geologic mapping of the northeastern Harney Basin -- along a corridor east of Highway 395 between the towns of Burns and John Day -- provides a more detailed understanding of an area originally mapped only in reconnaissance during the 1960s. At that time, geologic units were poorly delineated, often with entire quadrangles mapped as a single unit. For example, over 90% of the Calamity Butte quadrangle was previously mapped as \u27Tba\u27 (Tertiary basalt and andesite), and similarly substantial portions of the adjacent Jump-off Joe Mountain quadrangle were mapped as \u27Ts\u27 (Strawberry Volcanics). This area lies at the intersection of two of the oldest formations of the Columbia River Basalt Group (CRBG) – the Picture Gorge Basalt (PGB) and Steens Basalt – as well as just south of the younger Strawberry Volcanics (SVB). Accurately assigning newly mapped basalt units is therefore critical to refining the regional volcanic framework.
Geochemical, petrographic, and age data from 48 unassigned basalt samples, mapped and collected during this study as well as compiled from recent quadrangle maps, were compared with regional basalt lava members and classified using machine learning algorithms. These models predicted that the samples corresponded to one of the following three units: (1) Picture Gorge Basalt (PGB), as suggested by Cahoon et al. ; (2) Steens Basalt, as suggested by Camp et al. ; or (3) Strawberry Volcanics Basalt (SVB). While these units are compositionally similar, distinct differences appear in bivariate plots of key major oxides (TiO₂, Al₂O₃, P₂O₅), trace elements (V, Zn, La, Ba, Th, Nb, Y, Hf, Ta, Sr, Sc, Zr), and elemental ratios (TiO₂/P₂O₅, Cr/Ni, La/Nb, La/Yb, Ba/Nb, Zr/Y, Tb/Yb).
Using these diagnostic geochemical attributes and machine learning results, 31 unassigned basalts were classified as PGB, 6 as Steens Basalt, and 11 as SVB. This new dataset highlights unique characteristics among regional basalt lava members, extends the known distributions of PGB, Steens Basalt, and SVB, and enhances our understanding of the diverse volcanic history of eastern Oregon
oxygen is Not for the Dead : Critical and Radical Social Work in Palestine
No full textPalestinian poet and novelist Hiba Abu Nada, who was killed by an Israeli airstrike in Gaza on October 20, 2023, at the age of 32, taught us that “Oxygen is not for the dead.” Hiba Abu Nada’s (2017) poem, entitled “Our Loneliness,”1 recognizes survivance (Vizenor, 2010)—that is, the active sense of presence and presencing as an endeavor of creating the future (Simpson, 2017)—and asserts Palestinian embodied connections (Shalhoub-Kevorkian, 2024) to land/life (Khoury, 2019 [2016])
The Effects of Family Cohesion on the Relationship Between Trauma and State-Level Social Policy Provision in the United States
No full textThis dissertation examines how childhood trauma and family cohesion interact to shape state-level social policy generosity in the United States. The study begins with a multilevel quantitative analysis using data from the National Survey of Children’s Health and the State Safety-Net Generosity Index to assess how individual-level experiences of trauma and family support relate to state-level welfare generosity. Two trauma indices--one focused on adverse childhood experiences and bullying, and the other on food-related hardship--are used to explore how trauma influences attitudes toward public assistance, and whether family cohesion moderates this relationship. Results from marginal effects analyses indicate that family cohesion, particularly in low-trauma contexts, is associated with a slight reduction in support for generous policy, suggesting a complex and context-dependent moderating effect. Following the quantitative analysis, a qualitative comparative analysis (QCA) is conducted using most similar and most different systems design to identify combinations of factors--such as family cohesion, trauma prevalence, party control, and cultural conditions--that produce high or low levels of policy generosity across states. The QCA findings reinforce the importance of family cohesion while highlighting the interplay of structural and ideological factors. Together, these methods offer a multidimensional understanding of how relational and institutional forces shape social welfare generosity in the American federal system
Welcoming Historically Under-Represented Groups in Higher Education Through Awareness of Standard English Ideology
Get PDFIn the context of changing demographics at regional universities (including our own), we highlight an ongoing project at our university that addresses the last area of acceptable bias in English-medium higher education: bias against speakers of other languages and non-standard dialects of English. We discuss the hegemonic aspect of the Standard Academic English used by default at most US institutions of higher education and its role in potential discrimination against users of languages other than English and dialects other than the Standard. Data from over 2000 surveys, 55 follow up interviews, and three focus groups from faculty, staff and students in the university community are being analyzed. Preliminary findings show pervasive ignorance of the nature of language variation and how that plays a role in continuing discrimination against those who use other languages and diverse varieties of English even in our very multilingual setting. We conclude by outlining next steps, including the development of onboarding materials for new faculty, staff, and students
Begin Again: blooming
No full textBegin Again: blooming is a poetry thesis that explores the complexities of trauma, recovery, and identity through a feminist lens. Drawing from the lyric tradition, each poem serves as an emotional excavation, using voice, fragmentation, and address to create intimacy while resisting linear narrative and traditional poetic conventions.
The collection examines how pain imprints itself on the body and memory, with pieces like Dear Dad, Clean, and My Baby demonstrating the tension between tenderness and pain. Visually experimental and emotionally charged, these poems refuse erasure, reclaiming agency through raw articulation and form. Rather than seeking resolution, the speaker circles truth, inviting the reader into a space where confession is both act and artifact.
Begin Again: blooming asserts that healing is nonlinear—that to bloom is to survive and return to oneself again and again
More Than Hormones: Psychological Consequences of the Medicalized Menopausal Experience
No full textMenopause, a transitional period that roughly half the population may experience, has a high degree of variability in onset and intensity of symptoms, one of which is depression. It is also a period in which the lives of those transitioning are highly medicalized. This literature review investigates how medicalization has increased since the term was created, and how it impacts perimenopause, menopause, and mental health