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This capstone project is a completed draft of an illustrated field guide of Southern California seaweeds. The purpose of this was to create a region-specific and user-friendly guide for readers to learn about local seaweeds. This was done by collecting life specimens and illustrating them by hand with watercolor. The illustrations were digitized and put into a draft, along with supporting information about each species. The completed draft will be prepared and submitted for publication in print.

The ability of coyotes (Canis latrans) to exploit resources in human-dominated environments has led them to increasingly come into conflict with people, for example by killing domestic animals or attacking children. Additionally, coyotes in these environments increase their exposure to anthropogenic threats, such as harassment, vehicle mortality, and rodenticides. Effective management of human-coyote conflicts requires a better understanding of how coyotes navigate the developed landscape. As part of a broader study of how the use of urban and suburban areas affects coyotes’ exposure to rodenticides, we examined movements and space use of coyotes across gradients of urbanization in Los Angeles and Orange County, California. We affixed GPS radio-collars to 12 coyotes (nine males, three females) and tracked them between August 2022 and December 2023. Radio-collars recorded location information approximately every 15 min, but we restricted our analyses to hourly locations. We used a 95% minimum-convex polygon (MCP) and 95%-kernel density estimate (KDE) to calculate the area used by each animal. Within each utilization area, we calculated the amount of impervious cover and the relative amount of open space and development, using publicly-available GIS data layers (National Land-Cover Database; U.S. Geological Survey 2021). Additionally, for each coyote, we calculated a measure of movement tortuosity (straightness index, SI; Batschelet 1981) to describe its tendency to take directed, straight-line movements or wander less linearly in the habitat. We calculated SI for nine coyotes for which we had hourly location data during the first 28 days after radio-collar deployment. SI values were calculated separately for diurnal and nocturnal movements of each coyote, and then for movements when it was traveling in areas with low (≤19%) vs. high amounts of impervious cover (Wurth et al. 2020), and in areas classified as open space vs. areas with human development. We used paired t-tests to compare mean SI values because movements and habitat use of individual coyotes were not independent. Utilization areas of coyotes (Table 1) ranged from 0.4 - 136.1 km2 (95% MCP) and 0.4 - 148.2 km2 (95% KDE). Excluding three coyotes that displayed wide-ranging, transient movements and considering only five animals that were tracked intensively (151-313 days) during the breeding and dispersal seasons, mean utilization area (95% MCP) was 2.16 km2 (SD = 1.79), which is our best estimate of home-range size. This estimate is about half the size of that typically reported for urban coyotes elsewhere (approximately 5 km2; Gehrt 2007, Gehrt et al. 2009, Franckowiak et al. 2019), including in the Santa Monica Mountains of southern California (Riley et al. 2003). However, it is similar to the estimate (2.1 km2) of Tigas et al. (2002) for coyotes living in fragmented coastal sage scrub and chaparral habitats in Los Angeles and Ventura County, where the urban landscape resembles our study area. Considering only the five non-transient coyotes that we tracked most intensively, on average, 67.2% of their home range was categorized as open space, whereas 32.8% had some level of human development (low-high intensity categories). On average, 68.3% of their home ranges were in areas with little impervious cover (

Filamentous multicellular cable bacteria perform centimeter-scale electron transport in a process that couples oxidation of an electron donor (sulfide) in deeper sediment to the reduction of an electron acceptor (oxygen or nitrate) near the surface. While this electric metabolism is prevalent in both marine and freshwater sediments, detailed electronic measurements of the conductivity previously focused on the marine cable bacteria (Candidatus Electrothrix), rather than freshwater cable bacteria, which form a separate genus (Candidatus Electronema) and contribute essential geochemical roles in freshwater sediments. Here, we characterize the electron transport characteristics of Ca. Electronema cable bacteria from Southern California freshwater sediments. Current- voltage measurements of intact cable filaments bridging interdigitated electrodes confirmed their persistent conductivity under a controlled atmosphere and the variable sensitivity of this conduction to air exposure. Electrostatic and conductive atomic force microscopies mapped out the characteristics of the cell envelope's nanofiber network, implicating it as the conductive pathway in a manner consistent with previous findings in marine cable bacteria. Four-probe measurements of microelectrodes addressing intact cables demonstrated nanoampere currents up to 200 µm lengths at modest driving voltages, allowing us to quantify the nanofiber conductivity at 0.1 S/cm for freshwater cable bacteria filaments under our measurement conditions. Such a high conductivity can support the remarkable sulfide-to-oxygen electrical currents mediated by cable bacteria in sediments. These measurements expand the knowledgebase of long-distance electron transport to the freshwater niche while shedding light on the underlying conductive network of cable bacteria. [ABSTRACT FROM AUTHOR]

Waterways and water bodies worldwide are impacted by anthropogenic litter (hereafter "litter" or "trash"), generated from nonpoint sources. This study analyzes litter loads across various land uses within two Los Angeles County watersheds: the Ballona Creek and the Los Angeles River. Our objective is to present a methodology to develop buildup and washoff parameters for densely populated urban areas, such as the coastal metropolitan area of Los Angeles, California. An assessment is also made to test how these model parameters perform when applied to another urbanized watershed with similar rainfall and climate patterns (i.e., the San Diego River Watershed in California). Using extensive litter collection data from small drainages (approximately 572 locations, each draining 0.05–8.5 ha), we estimate buildup and washoff model parameters. These parameters are used to simulate the buildup of litter and subsequent washoff (load) of litter in our selected watersheds. Simulated results are validated against observed data from different years in all three watersheds. To date, no study has used litter washoff data to develop these parameters for stormwater models and applied them on a regional scale. We compared linear and nonlinear power functions of litter buildup during interstorm periods. Although there were limited data to develop washoff parameters, an exponential washoff function was used and calibrated to the observed washoff. Generally, storm events with the greatest antecedent dry days had the largest litter loading. Buildup rates varied among land uses, and key calibration parameters included the maximum buildup, buildup rate constant, washoff exponent, and washoff coefficient. A parameter sensitivity analysis was conducted to reveal the washoff exponent as the most sensitive parameter. Annual litter loading estimates were 4.60 kg/ha for the Ballona Creek and 11.50 kg/ha for the Los Angeles River. Litter loading estimates for Ballona Creek were validated and calibrated to align with observed data from the Ballona Creek Trash Interceptor, resulting in an annual washoff load of 2.1 kg/ha. The estimated annual litter loading for the Lower San Diego River was 2.15 kg/ha falling between the mean (0.77 kg/ha) and the maximum (3.56 kg/ha) observed values. When applying model parameters from one watershed to another, models require extensive calibration and validation data, as extrapolating data between watersheds can introduce errors. Practical Applications: This research can inform stormwater modelers about the process for developing parameters to estimate water quality in numerical modeling software. We demonstrate how data from field sampling can be directly used to develop model parameters. Results show that with proper validation data, stormwater models can accurately simulate annual litter loads in modeled watersheds. Future studies can test model parameters in other urbanized watersheds to validate the potential for standardized buildup values. Field studies can be done in conjunction with the results from this survey to investigate and further validate litter loads mobilized by stormwater. This study highlights the need for long-term monitoring to improve and update models in the future. Although there is a risk of inaccurate results when extrapolating model parameters from one watershed to another, this research indicates the potential for developing buildup and washoff parameters that can be used as a starting point for parameter selection across urban watersheds. [ABSTRACT FROM AUTHOR]

Species occupying dryland river ecosystems often experience "boom‐and‐bust" demographic cycles that coincide with shifts in habitat availability. Knowing whether declines are within natural thresholds versus those caused by acute human disturbance is critical for managing protected species. We investigated temporal shifts in abundance and habitat use of an endangered population of the threespine stickleback Gasterosteus aculeatus in southern California, where a Mediterranean climate leads to ephemeral habitat in one of the regions' least hydrologically modified rivers, the Santa Clara River. We conducted population surveys over a period of below‐average rainfall in the upper watershed in Soledad Canyon, with predefined reaches surveyed multiple times per year to capture different hydrologic conditions. Abundances were stable across years but varied significantly depending on location, with some reaches remaining dry and others drying seasonally to varying degrees. Occupancy models showed that the presence of stable perennial reaches, drying regime, and other site‐specific factors were important predictors of habitat use, and that certain reaches may be key to ensuring source‐sink dynamics as flow dissipates over the dry season. Low occupancy in two sections was driven by different predominant mechanisms, one by diel cycles of evapotranspiration and the other by cattails (Typha spp.), with both having greater effects during the hotter, drier parts of the year. As dryland river ecosystems are vulnerable to the effects of anthropogenic‐induced climate change, this study demonstrates how temporal monitoring can delimit dry‐state benchmarks for improving management interventions (i.e., translocation and habitat restoration) for protected species under conditions that are predicted to worsen in the coming years. [ABSTRACT FROM AUTHOR]

The cooling effect of the ocean on the Southern California coastal zone is investigated using a high‐resolution (4‐km) gridded surface meteorological data set (gridMET) of daily maximum temperature (Tmax), with focus on summer mean conditions, taken as the July–August–September (JAS) average. An empirical orthogonal function analysis reveals a coastal mode of JAS temperature covariability, distinct from a more energetic inland mode, that captures Tmax averaged across the Southern California coastal plain. The coastal mode temperature correlates significantly with, and has similar amplitude to, regional sea surface temperature (SST). High (low) summer land and sea surface temperatures, as well as inversion layer temperature differences, are associated with decreases (increases) of northerly coastal wind speeds and coastal cloudiness. The number of extreme heat days on land increases as regional SST increases (4.3 days °C−1), with heat wave days 10 times more likely during peak warm versus cool coastal mode years. The coastal zone was notably warmer and heat wave days peaked during the well documented marine heat wave events of 2014/15 and 2018 off Southern California. The marine variability associated with the coastal mode also has strong expression off the Baja California peninsula, presumably due to strong covarying winds in that area. As in previous studies, higher ocean temperatures are attributed to weaker summer winds, with associated reductions in ocean surface heat loss, coastal upwelling, and cloudiness. Plain Language Summary: Summer land temperatures across the Southern California coastal plain are moderated by proximity to the ocean, yet connections between year‐to‐year changes in summer land and ocean temperatures have not been fully quantified. Averages of July–September temperatures across the coastal plain are well described by a single mode of variability, which contributes to the number of extreme heat days in a given summer. Anomalously warm coastal land conditions are associated with reduced wind speeds and cloud/fog coverage and, most notably, warmer sea surface temperatures over the Southern California Bight and extending southward along the Baja California peninsula. Weak summer winds bring a reduction in ocean surface heat loss, coastal upwelling, and cloudiness, which contribute to higher sea surface temperatures. Strong winds lead to the opposite effect. This study highlights the multiple connections between marine and land heat waves in the SoCal region. Key Points: Summer‐averaged daily maximum land temperatures exhibit coherent spatial variations across the Southern California coastal plainCoastal land temperatures covary with regional ocean temperatures at a similar amplitude, as well as with surface winds and cloud coverThe number of extreme temperature days in the coastal zone varies with ocean conditions, notably during recent marine heat waves [ABSTRACT FROM AUTHOR]

Background Adolescents and young adults frequently receive chemotherapy near death. We know less about the use of targeted agents and immunotherapy or trends over time. Methods We conducted a retrospective cohort study of 1836 adolescents and young adults with cancer who died between 2009 and 2019 after receiving care at 1 of 3 sites (Dana-Farber Cancer Institute, Kaiser Permanente Northern California, and Kaiser Permanente Southern California). We reviewed electronic health data and medical records to examine use of cancer-directed therapy in the last 90 days of life, including chemotherapy, targeted therapy, immunotherapy, and investigational drugs. Results Over the study period, 35% of adolescents and young adults received chemotherapy in the last 90 days of life; 24% received targeted therapy, 7% immunotherapy, and 5% investigational drugs. Additionally, 56% received at least 1 form of systemic cancer-directed therapy in the last 90 days of life. After adjustment for patient sex, race, ethnicity, age, site of care, diagnosis, and years from diagnosis to death, the proportion of adolescents and young adults receiving targeted therapy (odds ratio [OR] = 1.05 per year of death, 95% confidence interval [CI] = 1.02 to 1.10; P  = .006), immunotherapy (OR = 1.27, 95% CI = 1.18 to 1.38; P  < .0001), and any cancer-directed therapy (OR = 1.04, 95% CI = 1.01 to 1.08; P  = .01) in the last 90 days of life increased over time. Conclusions More than half of adolescents and young adults receive cancer therapy in the last 90 days of life, and use of novel agents such as targeted therapy and immunotherapy is increasing over time. Although some adolescents and young adults may wish to continue cancer therapy while living with advanced disease, efforts are needed to ensure that use of cancer-directed therapy meets preferences of adolescents and young adults approaching death. [ABSTRACT FROM AUTHOR]

Large and diverse Eocene otolith assemblages have been described from the US Gulf and Atlantic coastal plains, various basins in Europe, and New Zealand. Here we described a highly diverse otolith association from the middle Eocene (Lutetian and Bartonian) strata of southern California, San Diego County, which was retrieved from the heritage of John E. Fitch (1918-1982) in the archives of the Ichthyology Department of the Natural History Museum of Los Angeles County, Los Angeles, Califronia. The collection represents the first Eocene otolith assemblage described from the Northeastern Pacific and stems from two localities: the Ardath Shale at Black’s Beach in the Torrey Pines Park just south of Black’s Canyon Road and north of the Salk Fault on the Pacific shore face, and the MissionValley Formation from the west-facing graded hill just east of the Miramar Water Treatment Plant near the southern shore of Miramar Reservoir. The Ardath Shale was deposited on the deep shelf and continental slope while the Mission Valley Formation represent an inland, nearshore environment during times of the maximum transgression. A total of more than15,000 otoliths were found representing 96 species of which 53 are described as new and 12 remain in open nomenclature. The fauna of the Ardath Shale is distinctly richer containing 88 species while the one from the Miramar Reservoir site yielded 38 species. The low diversity at the Miramar Reservoir site is thought to be related to the shallow-water environment in which it was deposited whereas the high diversity at Black’s Beach reflects a mixture of shelf and bathyal fishes. In addition, 24 new otolith-based genera are established, four of which are in the category “incertae sedis”. Furthermore, five new species are described from a comparative otolith collection from the US Gulf Coast Eocene and one new species from a comparative collection from the Lutetian of Balegem in Belgium. The Eocene otolith-based fish fauna from California is assessed for its paleoecological, paleobiogeographic and evolutionary significance. Particular emphasis is directed towards the elucidation of the evolution of the early Ophidiiformes, which during the early Paleogene were predominantly adapted to warm, clastic shallow-water environments and there were competing in abundance and diversity with other percomorphs (e.g., perciforms s.l.). A warm Eocene paleobioprovince is proposed for the Californian fish fauna which is not related to today’s endemic Northwest Pacific fish fauna along the regime of the cold-water California Current. [ABSTRACT FROM AUTHOR]

Multiculturalism has emerged in the last half-century as a leading if often embattled ideological stance celebrating the ethnic and racial diversity of the United States. One common interpretation traces it to the 1970s, acknowledging a minor precursor in the "cultural pluralism" advanced by intellectuals in the 1910s but casting multiculturalism itself as fundamentally new. Yet this depiction has been challenged by scholars re-examining American pluralist ideologies between World War I and the 1960s, finding that they had wider popularity, stronger institutional roots, and, at times, a role in shaping post-1970 multiculturalism. This new history puts that multiculturalism in a very different light. It is both new and old, a project that has broken with earlier pluralist projects in its broader reach and expanded categories of difference, but one that shares with them an inclusive approach to non-European groups, an institutional base, therapeutic interventions to improve intergroup relations, and a mass audience. This review essay examines the work of two groups of such historians. The first has located vibrant strands of pluralism in American civic culture from the 1920s into the 1960s and the footing they gained in schools, advocacy organizations, and the federal state. The second group has underlined the regional dimension of American pluralism in unearthing pluralist languages and movements in Southern California dating to the 1930s—projects that reflected that region's extraordinary diversity in their focus on multiple groups defined in terms of color. [ABSTRACT FROM AUTHOR]

Urbanization presents a natural evolutionary experiment because selection pressures in cities can be strongly mismatched with those found in species' historic habitats. However, some species have managed to adapt and even thrive in these novel conditions. When a species persists across multiple cities, a fundamental question arises: do we see similar traits evolve in similar novel environments? By testing if and how similar phenotypes emerge across multiple urban populations, we can begin to assess the predictability of population response to anthropogenic change. Here, we examine variation within and across multiple populations of a songbird, the dark-eyed junco (Junco hyemalis). We measured morphological variations in juncos across urban and nonurban populations in Southern California. We investigated whether the variations we observed were due to differences in environmental conditions across cities. Bill shape differed across urban populations; Los Angeles and Santa Barbara juncos had shorter, deeper bills than nonurban juncos, but San Diego juncos did not. On the other hand, wing length decreased with the built environment, regardless of the population. Southern Californian urban juncos exhibit both similarities and differences in morphological traits. Studying multiple urban populations can help us determine the predictability of phenotypic evolutionary responses to novel environments. [ABSTRACT FROM AUTHOR]

Justice-impacted persons may inconsistently access HIV testing. This cross-sectional secondary analysis investigates lifetime HIV testing prevalence among adults with prior histories of incarceration in Southern California, United States, participating in health-focused programming (n = 3 studies). Self-reported demographic and lifetime HIV testing data were collected between 2017–2023; descriptive analyses were conducted. Across the three samples, at least 74% of participants were male; Latino and African American individuals accounted for nearly two-thirds of participants. Lifetime HIV testing ranged from 72.8% to 84.2%. Males were significantly more likely than females to report never being tested in two samples and accounted for >95% of those never tested. No statistically significant differences in testing were observed by race/ethnicity. Single young adults (ages 18–26) were less likely than their partnered peers to report testing. HIV testing is critical for ensuring that individuals access prevention and treatment. HIV testing among justice-impacted adults in this study was higher than in the general population, potentially due to opt-out testing in correctional settings. Nevertheless, these findings underscore the importance of implementing targeted interventions to reduce structural (e.g., health insurance, access to self-testing kits) and social barriers (e.g., HIV stigma) to increase HIV testing among justice-impacted males and single young adults. [ABSTRACT FROM AUTHOR]

The unculturable bacterium 'Candidatus Liberibacter soianacearum' (CLso) is responsible for a growing number of emerging crop diseases. However, we know little about the diversity and ecology of CLso and its psyllid vectors outside of agricultural systems, which limits our ability to manage crop disease and understand the impacts this pathogen may have on wild plants in natural ecosystems. In North America, CLso is transmitted to crops by the native potato psyllid (Bactericera cockerelli). However, the geographic and host plant range of the potato psyllid and CLso beyond the borders of agriculture are not well understood. A recent study of historic herbarium specimens revealed that a unique haplotype of CLso was present infecting populations of the native perennial Solanum umbelliferum in California decades before CLso was first detected in crops. We hypothesized that this haplotype and other potentially novel CLso variants arc still present in S. umbelliferum populations. To test this, we surveyed populations of S'. umbelliferum in Southern California for CLso and potato psyllid vectors. We found multiple haplotypes of CLso and the potato psyllid associated with these populations, with none of these genetic variants having been previously reported in California crops. These results suggest that CLso and its psyllid vectors are much more widespread and diverse in North American natural plant communities than suggested by data collected solely from crops and weeds in agricultural fields. Further characterization of these apparently asymptomatic haplotypes will facilitate comparison with disease-causing variants and provide insights into the continued emergence and spread of CLso. [ABSTRACT FROM AUTHOR]

Abstract Seismicity in the Los Angeles metropolitan area has been primarily attributed to the regional stress loading. Below the urban areas, earthquake sequences have occurred over time showing migration off the faults and providing evidence that secondary processes may be involved in their evolution. Combining high-frequency seismic attenuation with other geophysical observations is a powerful tool for understanding which Earth properties distinguish regions with ongoing seismicity. We develop the first high-resolution 3D seismic attenuation models across the region east of downtown Los Angeles using 5,600 three-component seismograms from local earthquakes recorded by a dense seismic array. We present frequency-dependent peak delay and coda-attenuation tomography as proxies for seismic scattering and absorption, respectively. The scattering models show high sensitivity to the seismicity along some of the major faults, such as the Cucamonga fault and the San Jacinto fault zone, while a channel of low scattering in the basement extends from near the San Andreas fault westward. In the vicinity of the Fontana seismic sequence, high absorption, low scattering, and seismicity migration across a fault network suggest fluid-driven processes. Our attenuation and fault network imaging characterize near-fault zones and rock-fluid properties beneath the study area for future improvements in seismic hazard evaluation.

Understanding the generation of damaging, high‐frequency ground motions during earthquakes is essential both for fundamental science and for effective hazard preparation. Various theories exist regarding the origin of high‐frequency ground motions, including the standard paradigm linked to slip heterogeneity on the rupture plane, and alternative perspectives associated with fault complexity. To assess these competing hypotheses, we measure ground motion amplitudes in different frequency bands for 3 ≤ M ≤ 5.8 earthquakes in Southern California and compare them to empirical ground motion models. We utilize a Bayesian inference technique called the Integrated Nested Laplace Approximation (INLA) to identify earthquake source regions that produce higher or lower ground motions than expected. Our analysis reveals a strong correlation between fault complexity measurements and the high‐frequency ground motion event terms identified by INLA. These findings suggest that earthquakes on complex faults (or fault networks) lead to stronger‐than‐expected ground motions at high frequencies. Plain Language Summary: An important and unresolved question in earthquake science is how damaging, rapid ground shaking is generated during an earthquake. Various ideas currently exist to explain the cause of such ground motions, with the standard view attributing strong ground motion to frictional variations on the fault plane that ruptures during an earthquake. However, recent studies have also indicated that geometric complexities within fault networks may likewise influence the strong ground shaking. To help resolve this conundrum, we analyzed the ground motions produced by earthquakes in Southern California to assess the dependence of these ground motions to the complex fault networks on which the earthquakes occur. Our findings indicate that complex fault network systems have a substantial influence on how damaging earthquake ground shaking could be. These results have broad implications for our understanding of the physics of earthquakes and have important implications for earthquake hazards. Key Points: We investigate the influence of fault network complexity on the high‐frequency ground motions of earthquakes in CaliforniaWe observe a strong correlation between fault complexity and residual ground motions at high frequenciesThe correlation is frequency‐dependent, with stronger correlations observed at frequencies above 2 Hz [ABSTRACT FROM AUTHOR]

The Superstition Hills Fault (SHF) exhibits a rich spectrum of slip modes, including M 6+ earthquakes, afterslip, quasi‐steady creep, and both triggered and spontaneous slow slip events (SSEs). Following 13 years of quiescence, creepmeters recorded 25 mm of slip during 16–19 May 2023. Additional sub‐events brought the total slip to 41 mm. The event nucleated on the northern SHF in early‐May and propagated bi‐laterally at rates on the order of kilometers per day. Surface offsets reveal a bi‐modal slip distribution, with slip on the northern section of the fault being less localized and lower amplitude compared to the southern section. Kinematic slip models confirm systematic variations in the slip distribution along‐strike and with depth and suggest that slip is largely confined to the shallow sedimentary layer. Observations and models of the 2023 SSE bear a strong similarity to previous slip episodes in 1999, 2006, and 2010, suggesting a characteristic behavior. Plain Language Summary: Studying the mechanical properties and behavior of faults is essential for understanding earthquake ruptures. In this study, we investigate a recent slip event on the Superstition Hills Fault (SHF), which has a well‐documented record of slip. A notable aspect of the SHF is that it periodically undergoes "slow slip events" (SSEs), where the fault slips and releases energy without any accompanied ground shaking. During May‐July 2023, the SHF experienced a major SSE for the first time in 13 years. Our analysis shows that it was the largest documented SSE on the SHF and released equivalent energy to a magnitude 4.5 earthquake. We also find that the spatial pattern of fault slip is very similar to several previous slip events in 1999, 2006, and 2010, suggesting that the SHF has a tendency to slip in a characteristic manner. Key Points: We document a recent spontaneous slow slip event (SSE) on the Superstition Hills Fault using creepmeter, Interferometric Synthetic Aperture Radar, Global Navigation Satellite System, and field measurementsOver 41 mm of slip occurred from mid‐May to mid‐July 2023, with moment release corresponding to a Mw 4.5 earthquakeThe kinematics of the 2023 event are remarkably similar to several previous SSEs, suggesting a characteristic rupture process [ABSTRACT FROM AUTHOR]

Background: Patient participation in treatment decision making is a pillar of recovery-oriented care and is associated with improvements in empowerment and well-being. Although demand for increased involvement in treatment decision-making is high among veterans with serious mental illness, rates of involvement are low. Collaborative decision skills training (CDST) is a recovery-oriented, skills-based intervention designed to support meaningful patient participation in treatment decision making. An open trial among veterans with psychosis supported CDST's feasibility and demonstrated preliminary indications of effectiveness. A randomized control trial (RCT) is needed to test CDST's effectiveness in comparison with an active control and further evaluate implementation feasibility. Methods: The planned RCT is a hybrid type 1 trial, which will use mixed methods to systematically evaluate the effectiveness and implementation feasibility of CDST among veterans participating in a VA Psychosocial Rehabilitation and Recovery Center (PRRC) in Southern California. The first aim is to assess the effectiveness of CDST in comparison with the active control via the primary outcome, collaborative decision-making behavior during usual care appointments between veterans and their VA mental health clinicians, and secondary outcomes (i.e., treatment engagement, satisfaction, and outcome). The second aim is to characterize the implementation feasibility of CDST within the VA PRRC using the Practical Robust Implementation and Sustainability Model framework, including barriers and facilitators within the PRRC context to support future implementation. Discussion: If CDST is found to be effective and feasible, implementation determinants gathered throughout the study can be used to ensure sustained and successful implementation at this PRRC and other PRRCs and similar settings nationally. Trial registration: ClinicalTrials.gov NCT04324944. Registered on March 27, 2020. Trial registration data can be found in Appendix 1. [ABSTRACT FROM AUTHOR]

The association between SARS-CoV-2 humoral immunity and post-acute sequelae of COVID-19 (long COVID) remains uncertain. The objective of this population-based cohort study was to assess the association between SARS-CoV-2 seropositivity and symptoms consistent with long COVID. English and Spanish-speaking members ≥ 18 years old with SARS-CoV-2 serologic testing conducted prior to August 2021 were recruited from Kaiser Permanente Southern California and Kaiser Permanente Colorado. Between November 2021 and April 2022, participants completed a survey assessing symptoms, physical health, mental health, and cognitive function consistent with long COVID. Survey results were linked to SARS-CoV-2 antibody (Ab) and viral (RNA) lab results in electronic health records. Weighted descriptive analyses were generated for five mutually exclusive patient groups: (1) +Ab/+RNA; (2) +Ab/- or missing RNA; (3) -Ab/+RNA; (4a) -Ab/-RNA reporting no prior infection; and (4b) -Ab/-RNA reporting prior infection. The proportions reporting symptoms between the +Ab/+RNA and -Ab/+RNA groups were compared, adjusted for covariates. Among 3,946 participants, the mean age was 52.1 years old (SD 15.6), 68.3% were female, 28.4% were Hispanic, and the serologic testing occurred a median of 15 months prior (IQR = 12–18). Three quarters (74.5%) reported having had COVID-19. Among people with laboratory-confirmed COVID-19, there was no association between antibody positivity (+Ab/+RNA vs. -Ab/+RNA) and any symptoms, physical health, mental health, or cognitive function. As expected, physical health, cognitive function, and fatigue were worse, and palpitations and headaches limiting the ability to work were more prevalent among people with laboratory-confirmed prior infection and positive serology (+Ab/+RNA) compared to those without reported or confirmed prior infection and negative serology (-Ab/-RNA/no reported COVID-19). Among people with laboratory-confirmed COVID-19, SARS-CoV-2 serology from practice settings were not associated with long COVID symptoms and health status suggesting limited utility of serology testing for long COVID. [ABSTRACT FROM AUTHOR]

Recent studies on the experiences of gay Asian men demonstrate that members of these groups experience both subtle and blatant forms of racism within lesbian, gay, bisexual, transgender, and queer/questioning (LGBTQ) communities. This study expands on previous research by examining how gay Vietnamese American men experience racism within the gay community of Southern California, how racism affects members of this group mentally and emotionally, and their responses when facing racism. Based on 17 semi-structured, in-depth interviews with self-identified gay Vietnamese American men living in Southern California, this study found that they experienced racism similarly to other gay Asian men. Race and racism shape the everyday experiences of gay Vietnamese American men through the racial paradox of gay desire as they are either deemed undesirable and rejected as a potential sexual and romantic interest, or they are racially fetishized. However, members of this group do not experience racism passively but actively respond through various acts of resistance and intra-racial and ethnic community-building. [ABSTRACT FROM AUTHOR]

Warming in southern California during the 21st century is unprecedented in the instrumental record. To place this warming in a multi-century historical context, we analyzed tree ring data sampled from Jeffrey pine (Pinus jeffreyi) and sugar pine (Pinus lambertiana) collected from minimally disturbed, old-growth high-elevation forests within Mt. San Jacinto State Park California, USA. Based on a calibration/verification period of 1960–2020 between earlywood radial growth and California Climate Division 6 climate data, we reconstructed annual (November–October) minimum temperature (Tmin) from 1658 to 2020. During the 61-year calibration/verification period, instrumental Tmin increased (r = 0.69, p < 0.01) and was positively associated with annual radial growth (r = 0.71, p < 0.01). Using regime shift analysis, we found that the 363-year reconstruction revealed Tmin stability until 1958 and then decreased until 1980, followed by the two warmest regimes (1981–2007, 2008–2020) on record. The last 13-year period was 0.77 °C warmer than the multi-century average with nine of the ten warmest years in the reconstruction recorded. These results suggest that 21st century warming in southern California is unique in the context of the past four centuries, indicating the rarity of exceptional warmth captured in the tree ring record. [ABSTRACT FROM AUTHOR]

Graduate students of color have been entering graduate schools at unprecedented rates, yet these programs and institutions are not ready to fully support their unique needs. Using Yosso's Community Cultural Wealth framework, we showcase how graduate students of color utilize their cultural capital to succeed during their first year of graduate studies. We interviewed 10 graduate students from various graduate programs in Southern California and found that graduate students of color activated all six forms of cultural capital to persist through the challenges of their first year in graduate education. As graduate students of color used various forms of cultural capital to combat oppressive systems and structures during their first year, we call on graduate school programs and institutions to restructure and reimagine what support looks like for first-year graduate students of color by using an assets-based approach. [ABSTRACT FROM AUTHOR]

Background: Cisgender women account for 1 in 5 new HIV infections in the United States, yet remain under-engaged in HIV prevention. Women experiencing violence face risk for HIV due to biological and behavioral mechanisms, and barriers to prevention, such as challenges to Pre-Exposure Prophylaxis for HIV Prevention (PrEP) adherence. In this analysis, we aim to characterize intimate partner violence (IPV) among cisgender heterosexual women enrolled in a PrEP demonstration project and assess the associations with PrEP adherence. Methods: Adherence Enhancement Guided by Individualized Texting and Drug Levels (AEGiS) was a 48-week single-arm open-label study of PrEP adherence in HIV-negative cisgender women in Southern California (N = 130) offered daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC). From 6/2016 to 10/2018, women completed a survey reporting HIV risk behavior and experiences of any IPV (past 90-days) and IPV sub-types (past-year, lifetime) and biological testing for HIV/STIs at baseline, and concentrations of tenofovir-diphosphate (TFV-DP) in dried blood spots at weeks 4, 12, 24, 36, and 48. Outcomes were TFV-DP concentrations consistent with ≥ 4 or ≥ 6 doses/week at one or multiple visits. Multivariable logistic regression models were conducted to examine associations. Results: Past-90-day IPV was reported by 34.4% of participants, and past-year and lifetime subtypes reported by 11.5-41.5%, and 21.5-52.3%, respectively. Women who engaged in sex work and Black women were significantly more likely to report IPV than others. Lifetime physical IPV was negatively associated with adherence at ≥ 4 doses/week at ≥ 3 of 5 visits, while other relationships with any IPV and IPV sub-types were variable. Conclusion: IPV is an indication for PrEP and important indicator of HIV risk; our findings suggest that physical IPV may also negatively impact long-term PrEP adherence. Clinical Trials Registration: NCT02584140 (ClinicalTrials.gov), registered 15/10/2015. [ABSTRACT FROM AUTHOR]

The epidemic type aftershock sequence (ETAS) model is used as a baseline model both for earthquake clustering and earthquake prediction. In most forecast experiments, the ETAS parameters are estimated based on a short and local catalog, therefore the model parameter optimization carried out by means of a maximum likelihood estimation may be not as robust as expected. We use Bayesian forecast techniques to solve this problem, where non-informative flat prior distributions of the parameters is adopted to perform forecast experiments on 3 mainshocks occurred in Southern California. A Metropolis–Hastings algorithm is employed to sample the model parameters and earthquake events. We also show, through forecast experiments, how the Bayesian inference allows to obtain a probabilistic forecast, differently from one obtained via MLE. [ABSTRACT FROM AUTHOR]

Background and aims: Population-based screening for gastric cancer (GC) in low prevalence nations is not recommended. The objective of this study was to develop a risk-prediction model to identify high-risk patients who could potentially benefit from targeted screening in a racial/ethnically diverse regional US population. Methods: We performed a retrospective cohort study from Kaiser Permanente Southern California from January 2008-June 2018 among individuals age ≥50 years. Patients with prior GC or follow-up <30 days were excluded. Censoring occurred at GC, death, age 85 years, disenrollment, end of 5-year follow-up, or study conclusion. Cross-validated LASSO regression models were developed to identify the strongest of 20 candidate predictors (clinical, demographic, and laboratory parameters). Records from 12 of the medical service areas were used for training/initial validation while records from a separate medical service area were used for testing. Results: 1,844,643 individuals formed the study cohort (1,555,392 training and validation, 289,251 testing). Mean age was 61.9 years with 53.3% female. GC incidence was 2.1 (95% CI 2.0–2.2) cases per 10,000 person-years (pyr). Higher incidence was seen with family history: 4.8/10,000 pyr, history of gastric ulcer: 5.3/10,000 pyr, H. pylori: 3.6/10,000 pyr and anemia: 5.3/10,000 pyr. The final model included age, gender, race/ethnicity, smoking, proton-pump inhibitor, family history of gastric cancer, history of gastric ulcer, H. pylori infection, and baseline hemoglobin. The means and standard deviations (SD) of c-index in validation and testing datasets were 0.75 (SD 0.03) and 0.76 (SD 0.02), respectively. Conclusions: This prediction model may serve as an aid for pre-endoscopic assessment of GC risk for identification of a high-risk population that could benefit from targeted screening. [ABSTRACT FROM AUTHOR]

Where's Whaledo is a software toolkit that uses a combination of automated processes and user interfaces to greatly accelerate the process of reconstructing animal tracks from arrays of passive acoustic recording devices. Passive acoustic localization is a non-invasive yet powerful way to contribute to species conservation. By tracking animals through their acoustic signals, important information on diving patterns, movement behavior, habitat use, and feeding dynamics can be obtained. This method is useful for helping to understand habitat use, observe behavioral responses to noise, and develop potential mitigation strategies. Animal tracking using passive acoustic localization requires an acoustic array to detect signals of interest, associate detections on various receivers, and estimate the most likely source location by using the time difference of arrival (TDOA) of sounds on multiple receivers. Where's Whaledo combines data from two small-aperture volumetric arrays and a variable number of individual receivers. In a case study conducted in the Tanner Basin off Southern California, we demonstrate the effectiveness of Where's Whaledo in localizing groups of Ziphius cavirostris. We reconstruct the tracks of six individual animals vocalizing concurrently and identify Ziphius cavirostris tracks despite being obscured by a large pod of vocalizing dolphins. Author summary: Reconstructing the movement of animals from their vocalizations is a powerful method to observe their behavior in situations where visual monitoring is impractical. Arrays of acoustic recording devices can be used to determine the location of vocalizing animals and a series of locations can be linked to form tracks. However, reconstructing tracks requires methods of determining which animal in a group is vocalizing, finding the same vocalization on multiple recording devices, and determining the most likely location of the animal based on the relative times the sound arrived at various recording devices. We have developed a toolkit called Where's Whaledo to assist researchers in reconstructing the behavior of these animals using arrays of acoustic recording devices. This toolkit greatly accelerates the process of reconstructing their tracks using a combination of automated processes and user interfaces. We use Where's Whaledo to reconstruct the tracks of deep-diving beaked whales (Ziphius cavirostris). We successfully reconstruct tracks of groups of up to five whales vocalizing concurrently. [ABSTRACT FROM AUTHOR]

Seismic moment accumulation rate is a fundamental parameter for assessing seismic hazard. It can be estimated geodetically from either fault‐based modeling, or strain rate‐based calculations, where fault‐based models largely depend on the rheological layering and the number of faults. The strain‐rate method depends on an unknown (Kostrov) thickness used to convert strain rate into moment rate. In Part 1 of this study, we use three published fault‐based models from southern California to establish the value of the Kostrov thickness such that the total moment from the strain‐rate approach, calculated from the fault model‐predicted strain rate, matches the fault‐based approach. Constrained thickness estimates of 7.3, 9.7, and 11.5 km (6.4–13.0 km, including uncertainties) suggest that the 11 km value used in previous studies may be too large and a lower value may be more accurate. In Part 2 we use calibrated values of Kostrov thickness, along with the latest compilation of GNSS velocity data, to partition moment rate into on‐fault and off‐fault moment rate, where off‐fault varies from 32%–43% of the total moment rate. The largest uncertainty is related to the method used to interpolate sparse GNSS data. Lastly, we compare our estimates of total moment rate (mean: 2.13 ± 0.42 × 1019 Nm/yr) with the historical seismic catalog. Results suggest that including uncertainties in Kostrov thickness brings fault‐based geodetic moment rate closer to the seismic moment release (particularly when aseismic afterslip is accounted for), while the (uncertain) values of off‐fault moment rate push geodetic moment rates to be larger than seismic moment rates. Plain Language Summary: One commonly‐used method of evaluating the future earthquake potential of a known fault is to estimate the moment rate accumulating along that fault. In other words, one can estimate how much earthquake energy is accumulating over time, caused by the forces that propel plate boundary motion along fault systems. Two ways to do this are: (a) using detailed fault models of plate boundary motion, which are constrained by satellite‐based measurements of surface motion or (b) using those satellite‐based measurements directly through the estimation of regional strain rate. Here, we investigate the uncertainties present in the latter method by comparing previously published estimates of fault‐based moment rate, with their equivalent strain rate‐based versions. We estimate uncertainties related to the strain‐rate based method, which can lead to an over‐ or under‐estimation of earthquake potential on a given fault system. In addition, we explore the off‐fault moment rate accumulation in southern California which can help identify areas of enhanced moment accumulation and thus increased seismic hazard. Key Points: Previously published fault‐based models can constrain a Kostrov thickness range of 6.4–13.0 km, including uncertaintiesDifferences between strain rate moment estimates and fault‐based estimates suggest 32%–43% off‐fault moment rate in southern CaliforniaThe largest uncertainty in estimating moment rate from strain rate is the degree of smoothing used to estimate strain from geodetic data [ABSTRACT FROM AUTHOR]

Pica, the urge to consume items generally not considered food, such as dirt, raw starch, and ice, are particularly common among pregnant women. However, the biology of pica in pregnancy is not well understood. Therefore, this study aimed to assess how pica relates to endocrine stress and immune biomarkers in a cohort of pregnant Latina women in Southern California. Thirty‐four women completed a structured pica questionnaire. Maternal urinary cortisol and plasma cytokine levels were measured between 21 and 31 weeks' gestation. Associations between pica during pregnancy and biomarkers were assessed using linear regression models adjusting for gestational age. Twelve (35.3%) of the pregnant women reported pica (geophagy and amylophagy) during pregnancy. In multivariate models, those who engaged in pica had higher levels of cortisol (β: 0.37, 95% CI: 0.01, 0.073) and lower levels of IL‐1β (β: −0.06, 95% CI: −0.11, −0.02), IL‐8 (β: −0.30, 95% CI: −0.56, −0.05), IL‐21 (β: −0.35, 95% CI: −0.63, −0.08), and type‐1 inflammation composite (β: −0.29, 95% CI: −0.44, −0.14) than women who did not engage in pica. These results suggest that biological stress and immune response differ for women with pica compared to those without. This study suggests novel physiological covariates of pica during pregnancy. Further research is needed to better understand the mechanisms and temporality underlying the observed associations between pica and endocrine and immune biomarkers. [ABSTRACT FROM AUTHOR]

Purpose: Magnetic resonance imaging has been recommended as a primary imaging modality among high-risk individuals undergoing screening for pancreatic cancer. We aimed to delineate potential precursor lesions for pancreatic cancer on MR imaging. Methods: We conducted a case–control study at Kaiser Permanente Southern California (2008–2018) among patients that developed pancreatic cancer who had pre-diagnostic MRI examinations obtained 2–36 months prior to cancer diagnosis (cases) matched 1:2 by age, gender, race/ethnicity, contrast status and year of scan (controls). Patients with history of acute/chronic pancreatitis or prior pancreatic surgery were excluded. Images underwent blind review with assessment of a priori defined series of parenchymal and ductal features. We performed logistic regression to assess the associations between individual factors and pancreatic cancer. We further assessed the interaction among features as well as performed a sensitivity analysis stratifying based on specific time-windows (2–3 months, 4–12 months, 13–36 months prior to cancer diagnosis). Results: We identified 141 cases (37.9% stage I-II, 2.1% III, 31.4% IV, 28.6% unknown) and 292 matched controls. A solid mass was noted in 24 (17%) of the pre-diagnostic MRI scans. Compared to controls, pre-diagnostic images from cancer cases more frequently exhibited the following ductal findings: main duct dilatation (51.4% vs 14.3%, OR [95% CI]: 7.75 [4.19–15.44], focal pancreatic duct stricture with distal (upstream) dilatation (43.6% vs 5.6%, OR 12.71 [6.02–30.89], irregularity (42.1% vs 6.0%, OR 9.73 [4.91–21.43]), focal pancreatic side branch dilation (13.6% vs1.6%, OR 11.57 [3.38–61.32]) as well as parenchymal features: atrophy (57.9% vs 27.4%, OR 46.4 [2.71–8.28], focal area of signal abnormality (39.3% vs 4.8%, OR 15.69 [6.72–44,78]), all p < 0.001). Conclusion: In addition to potential missed lesions, we have identified a series of ductal and parenchymal features on MRI that are associated with increased odds of developing pancreatic cancer. [ABSTRACT FROM AUTHOR]

Three years after the 2015 collapse of the northern stock of Pacific Sardine that is predominantly located off the west coast of the United States, acoustic‐trawl (A‐T) surveys documented an increase in the presence and persistence of the southern stock off coastal Southern California. Then in 2020, the biomass of Sardine that was landed in Mexico and attributed to the northern stock exceeded the estimated biomass for the entire northern stock. To investigate if the landings were incorrectly classified, we revisit a model of northern‐stock potential habitat and the associated range of sea‐surface temperature (SST) used to apportion the A‐T survey data and monthly fishery landings to the two stocks, respectively. We update the probabilistic model of potential habitat with data on sardine‐egg presence and absence and concomitant satellite‐sensed SST and chlorophyll‐a concentration through 2019 and apply the new model to more accurately attribute the A‐T observations and fishery landings data to the northern or southern stock. The addition of recent data, with increased coverage in SSTs between 15°C and 17°C, improves the model accuracy and spatial precision of the stock attribution. The attribution accuracy is critically dependent on the temporal and spatial coincidence of the environmental and survey or landings data and should be corroborated with other characteristics indicative of biological isolation such as spatial separation, distinct spawning areas and seasons, and uncorrelated demographics. [ABSTRACT FROM AUTHOR]

We apply the Ralph et al. scaling method to a reanalysis dataset to examine the climatology and variability of landfalling atmospheric rivers (ARs) along the western North American coastline during 1980–2019. The local perspective ranks AR intensity on a scale from 1 (weak) to 5 (strong) at each grid point along the coastline. The object-based perspective analyzes the characteristics of spatially independent and temporally coherent AR objects making landfall. The local perspective shows that the annual AR frequency of weak and strong ARs along the coast is highest in Oregon and Washington and lowest in Southern California. Strong ARs occur less frequently than weak ARs and have a more pronounced seasonal cycle. If those ARs with integrated water vapor transport (IVT) weaker than 250 kg m−1 s−1 are included, there is an enhanced seasonal cycle of AR frequency in Southern California and a seasonal cycle of AR intensity but not AR frequency in Alaska. The object-based analysis additionally indicates that strong ARs at lower latitudes are associated with stronger wind than weak ARs but similar moisture, whereas strong ARs at higher latitudes are associated with greater moisture than weak ARs but similar wind. For strong ARs, IVT at the core is largest for ARs in Oregon and Washington and smaller poleward and equatorward. Both IVT in the AR core and cumulative IVT along the coastline usually decrease after the first day of landfall for weak ARs but increase from the first to second day for strong ARs. [ABSTRACT FROM AUTHOR]

Facilitative associations between the foundational shrub species Ephedra californica and local vertebrate species can drive positive interactions within desert ecosystems that influence diversity and assembly processes. These foundational shrubs can contribute to the structural heterogeneity of ecosystems for plants and animals including variation in temperature profiles, refuge from predation, and habitat for foraging. Artificial structures can also influence fine‐scale ecological and micro‐environmental dynamics. We tested the hypothesis that artificial shrubs (mimics) positively influence desert vertebrate association through facilitative interactions, similar to foundational shrub species. Mimics were deployed at four distinct sites within the central deserts of Southern California. A combination of camera traps and temperature pendants were utilized to measure the association patterns of vertebrate species and the microclimatic variation at mimic, open, and shrubs. A total of 21 species were observed in this study. Mimics had a significantly higher vertebrate abundance and richness than open microsites and functioned similarly to shrubs. These findings suggest that mimics can be utilized as a stop‐gap replacement for foundational shrub species as they can act as a novel fine‐scale habitat for many desert vertebrate species. [ABSTRACT FROM AUTHOR]

Assessing the co-occurrence of multiple health risk factors in coastal ecosystems is challenging due to the complexity of multi-factor interactions and limited availability of simultaneously collected data. Understanding co-occurrence is particularly important for risk factors that may be associated with, or occur in similar environmental conditions. In marine ecosystems, the co-occurrence of harmful algal bloom toxins and bacterial pathogens within the genus Vibrio may impact both ecosystem and human health. This study examined the co-occurrence of Vibrio spp. and domoic acid (DA) produced by the harmful algae Pseudo-nitzschia by (1) analyzing existing California Department of Public Health monitoring data for V. parahaemolyticus and DA in oysters; and (2) conducting a 1-year seasonal monitoring of these risk factors across two Southern California embayments. Existing public health monitoring efforts in the state were robust for individual risk factors; however, it was difficult to evaluate the co-occurrence of these risk factors in oysters due to low number of co-monitoring instances between 2015 and 2020. Seasonal co-monitoring of DA and Vibrio spp. (V. vulnificus or V. parahaemolyticus) at two embayments revealed the co-occurrence of these health risk factors in 35% of sampled oysters in most seasons. Interestingly, both the overall detection frequency and co-occurrence of these risk factors were considerably less frequent in water samples. These findings may in part suggest the slow depuration of Vibrio spp. and DA in oysters as residual levels may be retained. This study expanded our understanding of the simultaneous presence of DA and Vibrio spp. in bivalves and demonstrates the feasibility of co-monitoring different risk factors from the same sample. Individual programs monitoring for different risk factors from the same sample matrix may consider combining efforts to reduce cost, streamline the process, and better understand the prevalence of co-occurring health risk factors. [ABSTRACT FROM AUTHOR]

While juvenile white sharks (JWS) can display regional endothermy, the need to maintain internal temperatures within an energetically favorable range likely drives thermoregulatory movements to maximize growth and foraging efficiency. Many JWS from the northeastern Pacific population aggregate seasonally in nearshore nursery habitats throughout the Southern California Bight and historic data show that inter-seasonal movement patterns may be heavily dependent on ambient water temperature. However, the degree to which micro-scale (e.g., ~10 m²) water temperature heterogeneity influences JWS three-dimensional movement within nearshore aggregation sites is unknown. High-resolution temperature and passive acoustic-telemetry geo-positional data were used to quantify how temperature and vertical thermal stratification influenced JWS movement using several modeling approaches. JWS selected for water temperatures between 16 - 22°C and depths shallower than 2 m. Sharks occupied deeper waters during dawn and dusk periods, and their distance from the seafloor and spatial orientation of their depth distribution was significantly related to the thermal structure of the water column across the monitored area. Tagged sharks remained above a 16°C thermal threshold and altered their horizontal and vertical distributions accordingly. While high-resolution movement and environmental data provide improved predictability of microscale habitat use and distribution, other variables such as prey distribution, behavior, and competition would further improve habitat use models for this highly mobile species. [ABSTRACT FROM AUTHOR]

We develop basin-depth-scaling models (i.e. "basin terms") from the long-period (T ≥ 2 s) simulated ground motions of the Southern California Earthquake Center (SCEC) CyberShake project for use in seismic hazard analyses at sites within the sedimentary basins of southern California. Basin terms use the Next Generation Attenuation (NGA)-West-2 ground-motion models (GMMs) as reference models and use their functional forms with slight modifications. We investigate the use of two approaches to incorporate the time-averaged shear-wave velocity in the upper 30 m ( V S 30 ) in these calculations and find that the use of site-specific and uniform V S 30 has minor effects on the resulting basin terms for this data set. By centering the simulated ground motions on the basin terms, we separate the information from the simulations about absolute ground-motion level from information relating to the relative amplifications, such as the differences between shallow- and deep-basin sites. Recent observations from sedimentary basins of southern California indicate that additional amplification effect may persist at relatively shallow basin depths (i.e. the GMM basin terms should have positive values when differential depths, δ Z 1 , are near zero), and we present models for "centered" and "adjusted" basin-depth scaling models that reflect this potential. The simulation-modified GMMs are appropriate for crustal sources and for deep-basin sites (δ Z 1 > 0) within basins of the Greater Los Angeles region, for the magnitudes and distances defined by each of the reference NGA-West-2 GMMs. [ABSTRACT FROM AUTHOR]

Background: Epidemiological findings regarding the association of particulate matter ≤2.5 μm (PM2.5) exposure with hypertensive disorders in pregnancy (HDP) are inconsistent; evidence for HDP risk related to PM2.5 components, mixture effects, and windows of susceptibility is limited. We aimed to investigate the relationships between HDP and exposure to PM2.5 during pregnancy. Methods and findings: A large retrospective cohort study was conducted among mothers with singleton pregnancies in Kaiser Permanente Southern California from 2008 to 2017. HDP were defined by International Classification of Diseases-9/10 (ICD-9/10) diagnostic codes and were classified into 2 subcategories based on the severity of HDP: gestational hypertension (GH) and preeclampsia and eclampsia (PE-E). Monthly averages of PM2.5 total mass and its constituents (i.e., sulfate, nitrate, ammonium, organic matter, and black carbon) were estimated using outputs from a fine-resolution geoscience-derived model. Multilevel Cox proportional hazard models were used to fit single-pollutant models; quantile g-computation approach was applied to estimate the joint effect of PM2.5 constituents. The distributed lag model was applied to estimate the association between monthly exposure and HDP risk. This study included 386,361 participants (30.3 ± 6.1 years) with 4.8% (17,977/373,905) GH and 5.0% (19,381/386,361) PE-E cases, respectively. In single-pollutant models, we observed increased relative risks for PE-E associated with exposures to PM2.5 total mass [adjusted hazard ratio (HR) per interquartile range: 1.07, 95% confidence interval (CI) [1.04, 1.10] p < 0.001], black carbon [HR = 1.12 (95% CI [1.08, 1.16] p < 0.001)] and organic matter [HR = 1.06 (95% CI [1.03, 1.09] p < 0.001)], but not for GH. The population attributable fraction for PE-E corresponding to the standards of the US Environmental Protection Agency (9 μg/m3) was 6.37%. In multi-pollutant models, the PM2.5 mixture was associated with an increased relative risk of PE-E ([HR = 1.05 (95% CI [1.03, 1.07] p < 0.001)], simultaneous increase in PM2.5 constituents of interest by a quartile) and PM2.5 black carbon gave the greatest contribution of the overall mixture effects (71%) among all individual constituents. The susceptible window is the late first trimester and second trimester. Furthermore, the risks of PE-E associated with PM2.5 exposure were significantly higher among Hispanic and African American mothers and mothers who live in low- to middle-income neighborhoods (p < 0.05 for Cochran's Q test). Study limitations include potential exposure misclassification solely based on residential outdoor air pollution, misclassification of disease status defined by ICD codes, the date of diagnosis not reflecting the actual time of onset, and lack of information on potential covariates and unmeasured factors for HDP. Conclusions: Our findings add to the literature on associations between air pollution exposure and HDP. To our knowledge, this is the first study reporting that specific air pollution components, mixture effects, and susceptible windows of PM2.5 may affect GH and PE-E differently. Yi Sun and colleagues investigate the association between hypertensive disorders in pregnancy and particulate air pollution. Author summary: Why was this study done?: Although previous studies have explored the associations of particulate matter ≤2.5 μm (PM2.5) exposure with hypertensive disorders in pregnancy (HDP), earlier findings are inconclusive. Several unaddressed issues remain, such as lack of simultaneous consideration of PM2.5 constituents, mixture effects, windows of susceptibility, and levels of disease severity. What did the researchers do and find?: A retrospective cohort study (N = 386,361) was conducted using electronic health records from Kaiser Permanente Southern California (2008 to 2017) to examine the associations between HDP (mild HDP: gestational hypertension (GH) versus severe HDP: preeclampsia and eclampsia (PE-E)) and exposure to PM2.5, and identify windows of susceptibility to PM2.5 during pregnancy. We found higher risks for PE-E associated with exposures to PM2.5 total mass, organic matter, and black carbon, but not for GH. The main effect of increased PE-E risk was driven by PM2.5 black carbon (71%) and PM2.5 organic matter (26%). The most influential time windows of PM2.5 exposure associated with HDP are the late first trimester and second trimester. Hispanic and African American mothers and mothers who live in low- to middle-income neighborhoods may be more vulnerable to air pollution on HDP risk. What do these findings mean?: Our findings suggest that different PM2.5 chemical constituents and critical exposure windows may affect GH and PE-E differently. Our work highlights the need for further research to investigate different components of air pollutants, levels of disease severity, and various susceptible windows, which is important to better understand the underlying mechanisms between air pollution and HDP and develop corresponding interventions. [ABSTRACT FROM AUTHOR]

Across the Western United States, human development into the wildland urban interface (WUI) is contributing to increasing wildfire damage. Given that natural disasters often cause greater harm within socio-economically vulnerable groups, research is needed to explore the potential for disproportionate impacts associated with wildfire. Using Zillow Transaction and Assessment Database (ZTRAX), hereafter "Zillow", real estate data, we explored whether lower-priced structures were more likely to be damaged during the most destructive, recent wildfires in Southern California. Within fire perimeters occurring from 2000–2019, we matched property price data to burned and unburned structures. To be included in the final dataset, fire perimeters had to surround at least 25 burned and 25 unburned structures and have been sold at most seven years before the fire; five fires fit these criteria. We found evidence to support our hypothesis that lower-priced properties were more likely to be damaged, however, the likelihood of damage and the influence of property value significantly varied across individual fire perimeters. When considering fires individually, properties within two 2003 fires–the Cedar and Grand Prix-Old Fires–had statistically significantly decreasing burn damage with increasing property value. Occurring in 2007 and later, the other three fires (Witch-Poomacha, Thomas, and Woolsey) showed no significant relationship between price and damage. Consistent with other studies, topographic position, slope, elevation, and vegetation were also significantly associated with the likelihood of a structure being damaged during the wildfire. Driving time to the nearest fire station and previously identified fire hazard were also significant. Our results suggest that further studies on the extent and reason for disproportionate impacts of wildfire are needed. In the meantime, decision makers should consider allocating wildfire risk mitigation resources–such as fire-fighting and wildfire structural preparedness resources–to more socioeconomically vulnerable neighborhoods. [ABSTRACT FROM AUTHOR]

Introduction: The Coronavirus Disease 2019 (COVID-19) pandemic posed critical challenges in providing care to ovarian cancer (OC) patients, including delays in OC diagnosis and treatment initiation. To accommodate for delays in OC surgery, the Society of Gynecologic Oncology (SGO) recommended preferential use of neoadjuvant chemotherapy during the pandemic. The purpose of this study was to assess the association of the COVID-19 pandemic with neoadjuvant chemotherapy use in patients diagnosed with OC. Methods: This retrospective cohort study included patients diagnosed with stage II-IV ovarian cancer of epithelial subtype between 01/01/2017-06/30/2021 at Kaiser Permanente Southern California (KPSC), a large integrated healthcare system in the United States. Ovarian cancer patients diagnosed between 2017-2020 were identified from KPSC's Surveillance, Epidemiology, and End Results (SEER)-affiliated cancer registry. Patients diagnosed in 2021 were identified from the electronic medical records (EMR) using ICD-10 diagnosis codes, followed by medical chart review to validate diagnosis and extract information on histology and stage at diagnosis. March 4, 2020 was used as the cut-off to define prepandemic and pandemic periods. Patients diagnosed with COVID-19 between OC diagnosis and treatment completion were excluded. Data on neoadjuvant chemotherapy use were extracted from the cancer registry and EMR, supplemented by chart review. Modified Poisson regression was used to evaluate the association of the pandemic with neoadjuvant chemotherapy use. Results: Of 566 OC patients, 160 (28.3%) were diagnosed in the pandemic period. Patients diagnosed in the pandemic period were slightly younger (mean age 62.7 vs 64.9 years, p=0.07) and had a higher burden of Charlson comorbidities (p=0.05) than patients diagnosed in pre-pandemic period. No differences in time to treatment initiation were observed by pandemic periods. Neoadjuvant chemotherapy use was documented in 58.7% patients during the pandemic period compared to 47.3% in pre-pandemic period (p=0.01). After adjusting for covariates, patients diagnosed in the pandemic period were 29% more likely to receive neoadjuvant chemotherapy than patients diagnosed in pre-pandemic period [RR(95%CI): 1.29(1.12-1.49)]. Discussions: Ovarian cancer patients diagnosed in the COVID-19 pandemic were more likely to receive neoadjuvant chemotherapy than patients diagnosed before the pandemic. Future research on patient outcomes and trends in the post-pandemic period are warranted. [ABSTRACT FROM AUTHOR]

Background: In patients with new-onset heart failure (HF), coronary artery disease (CAD) testing remains underutilized. Whether widespread CAD testing in patients with new-onset HF leads to improved outcomes remains to be determined. Objective: We sought to examine whether CAD testing, and its timing, among patients hospitalized with new-onset HF with reduced ejection fraction (HFrEF), is associated with improved outcomes. Design: Retrospective cohort study. Participants: Adult (≥ 18 years) non-pregnant patients with new-onset HFrEF hospitalized within one of 15 Kaiser Permanente Southern California medical centers between 2016 and 2021. Key exclusion criteria included history of heart transplant, hospice, and a do-not-resuscitate order. Main Measures: Primary outcome was a composite of HF readmission or all-cause mortality through end of follow-up on 12/31/2022. Key Results: Among 2729 patients hospitalized with new-onset HFrEF, 1487 (54.5%) received CAD testing. The median age was 66 (56–76) years old, 1722 (63.1%) were male, and 1074 (39.4%) were White. After a median of 1.8 (0.6–3.4) years, the testing group had a reduced risk of HF readmission or all-cause mortality (aHR [95%CI], 0.71 [0.63–0.79]). These results were consistent across subgroups by history of atrial fibrillation, diabetes, renal disease, myocardial infarction, and elevated troponin during hospitalization. In a secondary analysis where CAD testing was further divided to early (received testing before discharge) and late testing (up to 90 days after discharge), there was no difference in late vs early testing (0.97 [0.81–1.16]). Conclusions: In a contemporary and diverse cohort of patients hospitalized with new-onset HFrEF, CAD testing within 90 days of hospitalization was associated with a lower risk of HF readmission or all-cause mortality. Testing within 90 days after discharge was not associated with worse outcomes. [ABSTRACT FROM AUTHOR]

A new species of leptostracan of the genus Nebalia, N. holothurophila, is described from southern California. The new species appears closely associated with the warty sea cucumber, Apostichopus parvimensis (H. L. Clark, 1913), although the exact nature of the relationship is unclear. The leptostracans were found in "transfer tubs" after the sea cucumbers were removed from artificial tidepools and placed in fresh seawater within these tubs. The new species differs from other leptostracans in southern California in having a combination of features not shared by any other species. [ABSTRACT FROM AUTHOR]

Positive interactions are underrepresented in marine ecology but have a substantial impact on biodiversity and ecosystem stability. Here, we showcase a previously undescribed commensal relationship between two temperate rocky reef fishes in sandy bottom habitats: the rock wrasse (Halichoeres semicinctus) and round stingray (Urobatis halleri). Using snorkel surveys in Big Fisherman's Cove on Santa Catalina Island, we showed that rock wrasse abundances were positively associated with the presence of round stingrays and that round stingrays significantly altered rock wrasse behavior. Specifically, rock wrasse within a 1 m radius of a feeding round stingray spent approximately 40% and 35% more time feeding compared to rock wrasse in proximity of a resting round stingray or a sandy bottom control, respectively. The positive effect of feeding round stingrays on rock wrasse feeding behavior is in response to stingrays disturbing sand as they eat, uncovering small invertebrates for the wrasses to prey on. As round stingrays are one of the most common fishes in southern California, they may impact the fitness of rock wrasses. [ABSTRACT FROM AUTHOR]

Southern California experienced unprecedented megadrought between 2012 and 2018. During this time, Malosma laurina, a chaparral species normally resilient to single‐year intense drought, developed extensive mortality exceeding 60% throughout low‐elevation coastal populations of the Santa Monica Mountains. We assessed the physiological mechanisms by which the advent of megadrought predisposed M. laurina to extensive shoot dieback and whole‐plant death. We found that hydraulic conductance of stem xylem (Ks, native) was reduced seven to 11‐fold in dieback adult and resprout branches, respectively. Staining of stem xylem vessels revealed that dieback plants experienced 68% solid‐blockage, explaining the reduction in water transport. Following Koch's postulates, persistent isolation of a microorganism in stem xylem of dieback plants but not healthy controls indicated that the causative agent of xylem blockage was an opportunistic endophytic fungus, Botryosphaeria dothidea. We inoculated healthy M. laurina saplings with fungal isolates and compared hyphal elongation rates under well‐watered, water‐deficit, and carbon‐deficit treatments. Relative to controls, we found that both water deficit and carbon‐deficit increased hyphal extension rates and the incidence of shoot dieback. Summary statement: We conclude that the ultimate cause of mortality of Malosma laurina in field populations was megadrought and that the proximal cause of mortality was the transition of endemic Botryosphaeria dothidea to an opportunistic pathogen that amplified protracted water stress through physical blockage of xylem water transport. [ABSTRACT FROM AUTHOR]

α-Dicarbonyls are significant degradation products resulting from the Maillard reaction during food processing. Their presence in foods can indicate the extent of heat exposure, processing treatments, and storage conditions. Moreover, they may be useful in providing insights into the potential antibacterial and antioxidant activity of U.S. honey. Despite their importance, the occurrence of α-dicarbonyls in honey produced in the United States has not been extensively studied. This study aims to assess the concentrations of α-dicarbonyls in honey samples from different regions across the United States. The identification and quantification of α-dicarbonyls were conducted using reverse-phase liquid chromatography after derivatization with o-phenylenediamine (OPD) and detected using ultraviolet (UV) and mass spectrometry methods. This study investigated the effects of pH, color, and derivatization reagent on the presence of α-dicarbonyls in honey. The quantification method was validated by estimating the linearity, precision, recovery, method limit of detection, and quantification using known standards for GO, MGO, and 3-DG, respectively. Three major OPD-derivatized α-dicarbonyls including methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG), were quantified in all the honey samples. 3-Deoxyglucosone (3-DG) was identified as the predominant α-dicarbonyl in all the U.S. honey samples, with concentrations ranging from 10.80 to 50.24 mg/kg. The total α-dicarbonyl content ranged from 16.81 to 55.74 mg/kg, with the highest concentration measured for Southern California honey. Our results showed no significant correlation between the total α-dicarbonyl content and the measured pH solutions. Similarly, we found that lower amounts of the OPD reagent are optimal for efficient derivatization of MGO, GO, and 3-DG in honey. Our results also indicated that darker types of honey may contain higher α-dicarbonyl content compared with lighter ones. The method validation results yielded excellent recovery rates for 3-DG (82.5%), MGO (75.8%), and GO (67.0%). The method demonstrated high linearity with a limit of detection (LOD) and limit of quantitation (LOQ) ranging from 0.0015 to 0.002 mg/kg and 0.005 to 0.008 mg/kg, respectively. Our results provide insights into the occurrence and concentrations of α-dicarbonyl compounds in U.S. honey varieties, offering valuable information on their quality and susceptibility to thermal processing effects. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change has increased the frequency of drought, wildfire, and invasions of non‐native species. Although high‐severity fires linked to drought can inhibit recovery of native vegetation in forested ecosystems, it remains unclear how drought impacts the recovery of other plant communities following wildfire. We leveraged an existing rainfall manipulation experiment to test the hypothesis that reduced precipitation, fuel load, and fire severity convert plant community composition from native shrubs to invasive grasses in a Southern California coastal sage scrub system. We measured community composition before and after the 2020 Silverado wildfire in plots with three rainfall treatments. Drought reduced fuel load and vegetation cover, which reduced fire severity. Native shrubs had greater prefire cover in added water plots compared to reduced water plots. Native cover was lower and invasive cover was higher in postfire reduced water plots compared to postfire added and ambient water plots. Our results demonstrate the importance of fuel load on fire severity and plant community composition on an ecosystem scale. Management should focus on reducing fire frequency and removing invasive species to maintain the resilience of coastal sage scrub communities facing drought. In these communities, controlled burns are not recommended as they promote invasive plants. [ABSTRACT FROM AUTHOR]

Fronting of the vowels /u, ʊ, o/ is observed throughout most North American English varieties, but has been analyzed mainly in terms of acoustics rather than articulation. Because an increase in F2, the acoustic correlate of vowel fronting, can be the result of any gesture that shortens the front cavity of the vocal tract, acoustic data alone do not reveal the combination of tongue fronting and/or lip unrounding that speakers use to produce fronted vowels. It is furthermore unresolved to what extent the articulation of fronted back vowels varies according to consonantal context and how the tongue and lips contribute to the F2 trajectory throughout the vowel. This paper presents articulatory and acoustic data on fronted back vowels from two varieties of American English: coastal Southern California and South Carolina. Through analysis of dynamic acoustic, ultrasound, and lip video data, it is shown that speakers of both varieties produce fronted /u, ʊ, o/ with rounded lips, and that high F2 observed for these vowels is associated with a front-central tongue position rather than unrounded lips. Examination of time-varying formant trajectories and articulatory configurations shows that the degree of vowel-internal F2 change is predominantly determined by coarticulatory influence of the coda. [ABSTRACT FROM AUTHOR]

Hot droughts, droughts attributed to below-average precipitation and exceptional warmth, are increasingly common in the twenty-first century, yet little is known about their effect on coniferous tree growth because of their historical rarity. In much of the American West, including California, radial tree growth is principally driven by precipitation, and narrow ring widths are typically associated with either drier or drought conditions. However, for species growing at high elevations (e.g., Larix lyalli, Pinus albicaulis), growth can be closely aligned with above-average temperatures with maximum growth coinciding with meteorological drought, suggesting that the growth effects of drought span from adverse to beneficial depending on location. Here, we compare radial growth responses of three high-elevation old-growth pines (Pinus jeffreyi, P. lambertiana, and P. contorta) growing in the San Jacinto Mountains, California, during a twenty-first-century hot drought (2000–2020) largely caused by exceptional warmth and a twentieth-century drought (1959–1966) principally driven by precipitation deficits. Mean radial growth during the hot drought was 12% above average while 18% below average during the mid-century drought illustrating that the consequences of environmental stress exhibit spatiotemporal variability. We conclude that the effects of hot droughts on tree growth in high-elevation forests may produce responses different than what is commonly associated with extended dry periods for much of western North America's forested lands at lower elevational ranges and likely applies to other mountainous regions (e.g., Mediterranean Europe) defined by summer-dry conditions. Thus, the climatological/biological interactions discovered in Southern California may offer clues to the unique nature of high-elevation forested ecosystems globally. [ABSTRACT FROM AUTHOR]

Inclusion of affordable housing in transit-oriented developments (TODs) is necessary for addressing the mobility and shelter needs of transit-dependent and low-income populations. Affordable housing in TODs, however, remains scarce despite state-level policies, interest group advocacy, and developer enthusiasm. We used a multiple case study method and focused on TOD areas in communities with disadvantaged populations in Southern California to examine barriers to and opportunities for affordable housing. We examined the contents of specific plans adopted by local governments to facilitate TODs around 10 selected transit stations in Los Angeles and Orange counties and conducted interviews with planners, policymakers, and developers involved in achieving affordable housing. Our findings indicated that although TOD specific plans permitted higher-density developments, they neither prioritized affordable housing nor presented a coherent vision for an inclusive transit community that would address the needs of different types of households. Moreover, onerous requirements for securing subsidies, patchwork financing, uncertainties in the approval process, and competition from market-rate housing inhibited affordable housing development. Although we did not analyze community opposition to TODs, it was hinted at by our interviewees. Targeting affordable housing in TODs, providing incentives, and strengthening the institutional framework are critical to achieving inclusive transit communities. The development of TODs in a politically fragmented region like Southern California necessitates a lead organization to procure affordable housing investments and strengthen the housing–transportation nexus. We note broader implications of the findings beyond California. [ABSTRACT FROM AUTHOR]

Infragravity (IG) waves are low-frequency water waves, which can propagate into harbors and estuaries, affecting currents and sediment transport processes. Understanding and predicting IG oscillations inside harbors and estuaries is critical to coastal management and estimating future resilience to climate change impacts. High-resolution water level and flow velocity observations collected within Seal Beach Wildlife Refuge in Southern California are analyzed for IG energy related to atmospheric parameters, water levels, and offshore wave conditions. A proof of concept approach for predicting infragravity oscillations within an estuary using machine learning (ML) is presented. [ABSTRACT FROM AUTHOR]

The global emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a critical public healthcare concern due to treatment challenges and high mortality. In recent years, there has been an increase in cases of CRKP co-producing New Delhi metallo-β-lactamases (NDM) and oxacillinase 48 (OXA-48)-like carbapenemases in the US. The aim of this study was to correlate the clinical and genomic characteristics of CRKP co-producing NDM and OXA-48-like carbapenemases isolated from patients in Southern California since 2016. Whole-genome sequencing was performed on clinical isolates obtained from various sources, including blood, abdominal fluid, wounds, and urine. Genetic diversity was observed in these CRKP, including ST-14, ST-16, ST-167, ST-437, ST-2096, and ST-2497 lineages. Phylogenetic analysis revealed two closely related clusters (ST-14 and ST-2497), with single nucleotide polymorphism (SNP) differences ranging from 0 to 36, suggesting a possible local spread of these CRKP. Significant antimicrobial resistance (AMR) genes were identified in these CRKP, including blaNDM-1, blaNDM-5, blaOXA-232, blaOXA-181, blaCTX-M-15, armA, tet(A), and tet(D). Moreover, pColKP3-type and Inc-type plasmids known to harbor AMR genes were also detected in these isolates. Most of the patients infected with this rare type of CRKP died, although their severe comorbidities also played important roles in their demise. Our study highlighted the extremely limited treatment options and poor clinical outcomes associated with these dual-carbapenemase-producing CRKP. Real-time genomic surveillance of these unusual and deadly CRKP can provide critical information for infection prevention and treatment guidance.

The southern California coast is well known for its surfing, beachfront towns, and high marine biodiversity. Humans share these coastal regions with species such as the green sea turtle (Chelonia mydas; hereafter referred to as “green turtle”). Over the last two decades, East Pacific (EP) green turtles have undergone substantial population recovery. As a result of improved protection efforts at nesting beaches and foraging areas in Michoacán, Mexico beginning in 1979 green turtles have been spotted in more areas and in greater numbers than before since 2014.1 An analysis of existing stranding and sighting data is necessary to protect the growing EP green turtle population and ensure their continued population recovery in highly populated areas along the California coast. While the existing green turtle recovery plan (completed in 1998) addresses EP green turtles, it is dated and does not specifically address current known threats to this population, particularly in southern California. 2 Therefore, this report and accompanying StoryMap (link: https://arcg.is/0eX1zK) provide analyses on time-relevant and local scales. With the support of experts from the National Oceanic and Atmospheric Administration’s (NOAA), National Marine Fisheries Service (NMFS), and the University of California San Diego, I review existing literature, analyze stranding and sighting data, and propose recommendations that could help reduce the human impacts on green turtles in the southern California region if implemented.Storymap for this project can be viewed here: https://storymaps.arcgis.com/stories/391c53f931dd45619347177810259dd3

BackgroundRecent evidence links ambient air pollution to COVID-19 incidence, severity, and death, but few studies have analyzed individual-level mortality data with high quality exposure models.MethodsWe sought to assess whether higher air pollution exposures led to greater risk of death during or after hospitalization in confirmed COVID-19 cases among patients who were members of the Kaiser Permanente Southern California (KPSC) healthcare system (N=21,415 between 06-01-2020 and 01-31-2022 of whom 99.85 % were unvaccinated during the study period). We used 1 km resolution chemical transport models to estimate ambient concentrations of several common air pollutants, including ozone, nitrogen dioxide, and fine particle matter (PM2.5). We also derived estimates of pollutant exposures from ultra-fine particulate matter (PM0.1), PM chemical species, and PM sources. We employed Cox proportional hazards models to assess associations between air pollution exposures and death from COVID-19 among hospitalized patients.FindingsWe found significant associations between COVID-19 death and several air pollution exposures, including: PM2.5 mass, PM0.1 mass, PM2.5 nitrates, PM2.5 elemental carbon, PM2.5 on-road diesel, and PM2.5 on-road gasoline. Based on the interquartile (IQR) exposure increment, effect sizes ranged from hazard ratios (HR) = 1.12 for PM2.5 mass and PM2.5 nitrate to HR ∼ 1.06-1.07 for other species or source markers. Humidity and temperature in the month of diagnosis were also significant negative predictors of COVID-19 death and negative modifiers of the air pollution effects.InterpretationAir pollution exposures and meteorology were associated the risk of COVID-19 death in a cohort of patients from Southern California. These findings have implications for prevention of death from COVID-19 and for future pandemics.