Areas Of California Research Articles

The Lau decision and the San Diego National Origin Desegregation Assistance Center

ABSTRACT This article documents the San Diego National Origin Desegregation Assistance Center (NODAC), one of the nine national centers established by the U.S. Office of Education to provide technical assistance to school districts cited under Section 601 of Title VI, from the Office for Civil Rights, to meet the Lau compliance requirement based on the Lau v. Nichols Supreme Court decision (Title VI. 42 U. S. C). Additionally, it provides insights into the ideological and political challenges and triumphs of implementing federal mandates for educational equity. The focus of this article is on the San Diego NODAC which provided technical assistance to the Southern California area consisting of 10 counties with the highest concentration of national origin students in the nation. This evaluation case study documents the work, process, and impact, of the San Diego NODAC and reflects on the enforcement of the Lau Task Force Remedies under the Region IX U.S. Office of Civil Rights, the process used by the NODAC, and the organizational receptivity and perceptions of school districts personnel responsible for coordinating compliance at or beyond minimal compliance. This article concludes with an evaluation process using lessons learned by the NODAC based on more than a decade of work and advocacy for students’ equal access to opportunity, quality bilingual education, and democratic schooling.

Squash vein yellowing virus from California emerged in the Middle East via intragenic and intergeneric recombination events in the hypervariable potyvirus P1 and ipomovirus P1a genes.

We present the complete sequence of the genomic RNA of an isolate of squash vein yellowing virus (Ipomovirus cucurbitavenaflavi) from California (SqVYV-CA) and show it is a recombinant virus with a highly divergent 5' UTR and proximal P1a gene. The evolution of SqVYV-CA involved an intrageneric event between unknown potyviruses, related to isolates of papaya ringspot virus (Potyvirus papayanuli) from the Old World, and an intergeneric event between this recombinant potyvirus (minor parent) and an isolate of SqVYV from Israel (SqVYV-IL) (major parent). These events occurred in mixed infections and in the potyvirus P1 and ipomovirus P1a recombination hotspots and resulted in SqVYV-CA having a potyvirus 5' UTR and chimeric P1-P1a gene/protein and the remainder of the genome from SqVYV-IL. The SqVYV-CA chimeric P1-P1a gene is under positive selection, and the protein is intrinsically disordered and may localize to the nucleus via nuclear localization signals in the P1 part. The C-terminal SqVYV-IL P1a part also diverged but retained the conserved serine protease motif. Furthermore, substantial divergence in SqVYV isolates from the Middle East was associated with genetic drift and a long evolutionary history in this region. The finding that the host range and symptomatology in cucurbits of SqVYV-CA is similar to those of SqVYV from Florida and SqVYV-IL, indicated that the recombinant part of the genome had no obvious effect on the virus-host interaction. A divergent part of the P1 sequence of the SqVYV-CA P1-P1a gene was used to develop a primer pair and RT-PCR test for specific detection of SqVYV-CA. This test was used to detect spread of SqVYV-CA to a new production area of California in 2021 and 2022. Together, these results demonstrate (i) a high level of genetic diversity exists among isolates of SqVYV and involved intra- and intergeneric recombination and genetic drift (mutation), (ii) evidence that SqVYV originated in the Middle East and that there were independent introductions into the New World and (iii) the remarkable genetic flexibility of the 5' proximal genes of these viruses.

Modelo cinemático del control estructural 4D y metalogénesis del distrito auroargentífero Vetas-California (Santander, Colombia)

). The gold and silver deposits of the Vetas-California mining district are hosted in Paleozoic gneisses and Mesozoic granites of the Santander massif in the Eastern Cordillera of Colombia, far from the northern Andean volcanic arc. In the California area, there is ambiguity in defining the epithermal-type metallogenic model with high to intermediate sulfidation due to the presence of Late Triassic-Early Jurassic and Miocene magmatism. The best-known hydrothermal episodes comprise two early porphyritic-style phases: a) characterized by a propylitic alteration with molybdenite of the ~10.1 Ma-old La Mascota breccia, related to granodiorite porphyries and smaller-volume rhyodacitic dykes; and b) attributed to a magmatic-hydrothermal system due to phyllic alteration associated with quartz-pyrite veins with hydrothermal sericite dated at ~3.4 Ma. These two hydrothermal episodes were followed by four epithermal phases related to the development of multiphase hydrothermal breccias and quartz-alunite alteration, defined by bornite, covellite, and chalcopyrite, alongside wolframite, enargite, and sphalerite, with gold and silver mineralization between ~2.6 and ~ 1.6 Ma. To understand the relationship of the emplacement of the porphyries and the subsequent auro-argentiferous enrichments to the deformation front observed in the Pamplona buttress, to the east of the Santander Massif, a 4D structural model of the mineralization is formulated here. This model is based on the spatial analysis of the stresses responsible for the La Baja-Angostura dextral fault in terms of the regional kinematics of the Bucaramanga sinistral fault. It is considered that the SW sector of the deposit area corresponds to a well-defined, tabular, sub-vertical body of the La Mascota breccia. On the other hand, the NE sector in the La Baja-Angostura fault is expressed as a topographically elevated right horsetail splay, which controls the more disseminated distribution of the mineralization by means of veinlet swarms arranged in an ~E-W direction. The disseminated mineralization of Vetas-California was probably favored by late thermal expansion-contraction events in the gneissic sockets, which allowed the accumulation and precipitation of boiling solutions rich in volatiles and elements of economic interest.

Tomato dry farming as an agroecological model for California’s drought resilient future: Farmers’ perspectives and experiences

Small, diversified farms on California’s Central Coast have been dry farming for decades, allowing farmers to use water stored in soils from winter rains to grow tomatoes and other vegetables with little-to-no irrigation in summers without rainfall. As recent water shortages in California have forced a reckoning with the precariousness of the state’s water supply, policy groups and the general public have become increasingly interested in dry farming as a promising means of achieving water conservation goals. Academic research on this practice, however, has been scarce. Amid growing urgency to develop low-water agricultural systems in the state, we interviewed 10 Central Coast dry farmers, representing over half of the commercial dry farm operations in the region where this practice was developed, to collaboratively answer 2 central research questions: (1) What business and land stewardship practices characterize successful tomato dry farming on California’s Central Coast? (2) What is the potential for dry farming to expand beyond its current adoption while maintaining its identity as a diversified practice that benefits small-scale operations? We summarize farmers’ wisdom into 9 themes about current dry farm practice, its potential for expansion and future opportunities. We also synthesize farmer-stated environmental constraints on dry farm feasibility into a map of suitable areas in California. As we consider how dry farming might expand to new areas and operations, we highlight dry farming’s history as an agroecological alternative to industrial farming in the region and the need for careful policy planning to maintain that identity. In examining this California Central Coast dry farming system, we ask if and how it can enhance the viability of nonindustrial farming operations as the food system adapts to less water availability. Because policies that encourage dry farm expansion could change economic landscapes in which dry farming operates, we caution that well-intentioned policies could edge small growers out of dry farm markets if not carefully designed. At the same time, we emphasize the opportunity for dry farm tomato systems to model an agroecological transition toward water savings in California.

In-Vehicle Air Pollutant Exposures from Daily Commute in the San Francisco Bay Area, California

With urbanization and increased vehicle usage, understanding the exposure to air pollutants inside the vehicles is vital for developing strategies to mitigate associated health risks. In-vehicle air quality influences the comfort of the driver during long commutes and has gained significant interest. This study focuses on studying in-vehicle air quality in the San Francisco Bay Area in California, an urban setting with significant traffic congestion and varied emission sources and road conditions. Each trip is about 80.5 km (50 miles) in length, with commute times of approximately one hour. Two low-cost portable sensors were employed to simultaneously measure in-vehicle pollutants (PM2.5, PM10, and CO2) during morning and evening rush hours from May 2023 to December 2023. Seasonally averaged PM2.5 varied from 5.07 µg/m3 to 6.55 µg/m3 during morning rush hours and from 4.38 µg/m3 to 4.47 µg/m3 during evening rush hours. In addition, the impacts of local PM2.5, vehicle ventilation settings, and speed of the vehicle on in-vehicle PM concentrations were also analyzed. CO2 buildup in vehicles was studied for two scenarios: one with inside recirculation enabled (RC on) and the other with circulation from outside (RC off). With RC off, CO2 concentrations are largely within the 1100 ppm range recommended by many organizations, while the average CO2 concentrations can be three times high under recirculation mode. This research suggests that low-cost sensors can provide valuable insights into the dynamics of air pollution in the in-vehicle microenvironment, which can better help commuters reduce health risks.

Meta-transcriptomic analysis reveals the geographical expansion of known sugarbeet-infecting viruses and the occurrence of a novel virus in sugarbeet in the United States.

In this study, meta-transcriptome sequencing was conducted on a total of 18 sugarbeet (Beta vulgaris L. subsp. vulgaris) sample libraries to profile the virome of field-grown sugarbeet to identify the occurrence and distribution of known and potentially new viruses from five different states in the United States. Sugarbeet roots with symptoms resembling rhizomania caused by beet necrotic yellow vein virus (BNYVV), or leaves exhibiting leaf-curling, yellowing to browning, or green mosaic were collected from the sugarbeet growing areas of California, Colorado, Idaho, Minnesota, and North Dakota. In silico analysis of de novo assembled contigs revealed the presence of nearly full-length genomes of BNYVV, beet soil-borne virus (BSBV), and beet soil-borne mosaic virus (BSBMV), which represent known sugarbeet-infecting viruses. Among those, BNYVV was widespread across the locations, whereas BSBV was prevalent in Minnesota and Idaho, and BSBMV was only detected in Minnesota. In addition, two recently reported Beta vulgaris satellite virus isoforms (BvSatV-1A and BvSatV-1B) were detected in new locations, indicating the geographical expansion of this known virus. Besides these known sugarbeet-infecting viruses, the bioinformatic analysis identified the widespread occurrence of a new uncharacterized Erysiphe necator-associated abispo virus (En_abispoV), a fungus-related virus that was identified in all 14 libraries. En_abispoV contains two RNA components, and nearly complete sequences of both RNA1 and RNA2 were obtained from RNASeq and were further confirmed by primer-walking RT-PCR and Sanger sequencing. Phylogenetic comparison of En_abispoV isolates obtained in this study showed varying levels of genetic diversity within RNA1 and RNA2 compared to previously reported isolates. The undertaken meta-transcriptomic approach revealed the widespread nature of coexisting viruses associated with field-grown sugarbeet exhibiting virus disease-like symptoms in the United States.

Increasing Awareness and Uptake of Connected Insulin Pens for Eligible Patients With Diabetes: A Quality Improvement Success Story.

Quality Improvement Success Stories are published by the American Diabetes Association in collaboration with the American College of Physicians and the National Diabetes Education Program. This series is intended to highlight best practices and strategies from programs and clinics that have successfully improved the quality of care for people with diabetes or related conditions. Each article in the series is reviewed and follows a standard format developed by the editors of Clinical Diabetes. The following article is part of a special article collection from the T1D Exchange Quality Improvement Collaborative. It describes an initiative to increase the use of connected insulin pens in two primary care clinics and one endocrinology clinic serving diverse populations within the Stanford Health Care system in the San Francisco Bay area of California.

Impacts of COVID-19 shelter in place across key life domains among immigrant farmworker Latina mothers and young adults

ObjectiveIndividuals and families from racial and ethnic groups experience social and economic disadvantage making them vulnerable to the disproportionate impact of the COVID-19 pandemic. This study sought to capture the impacts of Shelter in Place (SIP) across key life domains including family life, education, work, mental health, and coping strategies among a sample of Mexican-origin mothers who were currently engaged in agricultural work, or whose spouses were engaged in agricultural work, and young adults who had a parent working in agriculture.MethodDuring the summer of 2020, while California was under SIP orders, we conducted three virtual focus groups using Zoom(r). We recruited focus group participants from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), an ongoing, 20-year, longitudinal cohort study of Mexican-origin families in a predominantly agricultural area of California. Three focus groups were conducted with mothers (n = 9), mean age = 48 years, young adult women (n = 8) and young adult men (n = 5), mean age = 18 years, respectively.ResultsMothers reported high levels of stress stemming from fear of Covid-19 infection, work instability and financial concerns, children’s schooling, anxiety about an uncertain future, and the demands of caretaking for dependents. Adverse mental health impacts were particularly pronounced among participants experiencing multiple adversities pre-dating the pandemic, including unemployment, single motherhood, and having undocumented family members. For young adults, work instability and varying work hours were also a source of stress because they made it difficult to make decisions about the future, such as whether to attend college or how many classes to take. Families used coping strategies including expressing gratitude, focusing on what’s under one’s control, familismo, and community engagement to manage mental health challenges during SIP.ConclusionIn the event of future pandemics or disasters, particular attention is needed to those who experience unemployment, are undocumented and/or have undocumented family members, and/or are single parents facing economic adversity. During public health emergencies, action at the local, state, and national level is needed to support farmworkers and other vulnerable groups’ secondary major stressors stemming from inequities in access to affordable housing, childcare, living wages, healthcare, and other benefits.

Spatiotemporal analysis and forecasting of PV systems, battery storage, and EV charging diffusion in California: A graph network approach

Understanding the dynamics of clean energy adoption is crucial for shaping effective energy policies and strategies. To understand the spatiotemporal variability and bottom-up spontaneity of the diffusion of clean energy technologies, this study examined the spatiotemporal diffusion of Photovoltaic (PV) systems, Battery Energy Storage Systems (BESS), and Electric Vehicle Charging Stations (EVCS) across 1773 postcode areas in California over the past 35 years. The Bayesian change point detection algorithm (BCDA) was initially utilized to identify temporal change points in the evolution of these technologies, revealing their diffusion trends over time. Then, the Louvain community detection algorithm (LCDA) was employed to elucidate spatial diffusion patterns across regions, offering insights into the geographic proliferation of clean energy solutions. Furthermore, to forecast future distributions, the spatiotemporal graph convolutional network (STGCN) model was applied, adeptly capturing the multi-stage, nonlinear characteristics of clean energy diffusion marked by significant spatiotemporal interactions. With historical data and spatial proximity, the STGCN model demonstrated fine forecasting precision (R^2 ≥ 0.78). This study validates the effectiveness of a graph network-based approach for analyzing the diffusion of clean energy technologies. It recommends policies tailored to account for technological maturity, geographic disparities, and diffusion stages, aiming for equitable and sustainable clean energy development in the region.

Early impacts of fire suppression in Jeffrey pine – Mixed conifer forests in the Sierra San Pedro Martir, Mexico

Fire exclusion was first implemented across large areas of California and other areas of western North America in the late 19th or early 20th centuries but few studies have investigated how forests in the early decades after this decision were impacted. Jeffrey pine-mixed conifer forests of northern Baja California, Mexico, offer an area where this can be examined since fire suppression did not begin until the early 1970’s. We use repeated forest and fuel measurements taken over a 25-year period (1998–2023) and found significant changes in forest structure and fuel loads (increased tree density, fine fuel loads, large fuel loads, snag density, snag basal area) that together clearly demonstrate the cumulative effects of fire removal. Interestingly, Jeffrey pine became more dominant despite the lack of recent fire, which is counter to the shift towards more shade-tolerant tree species observed in many other fire-suppressed, frequent-fire forests in the western US. Although these changes in Baja California forests point towards increased fire hazard, they are still in relatively low hazard conditions compared to long-fire suppressed forests in the western US. Prescribed fire or managed wildfire could easily be applied to counter the increased fuel loads and tree densities detected in this work, without the need for mechanical manipulation. In addition to maintaining resilient forests, using fire will reduce the risk of losing the large astronomical observatory at this site to wildfire. Restoration and stewardship of resilient forest structures similar to those in Baja California is the only way forward to conserve similar forests of the Sierra Nevada, southern California mountains, and elsewhere in the western US.

Houston, you have a problem: How large cities accommodate more housing

AbstractWe document how a select set of large and growing metropolitan areas have accommodated growth in their housing supply over 40 years. In particular, we examine how housing provision has evolved for the largest four metropolitan statistical areas (MSAs) in California and Texas. Despite differences in their topographies and regulatory environments, we find several common dynamics. As these MSAs grow, we see that fewer new net units are built at the periphery and a smaller share of the new units are built as single‐family detached houses. As a greater share of new net units are built in infill locations, more units are built using higher‐density—and more costly—multifamily housing construction techniques. Interestingly, we see these housing supply patterns in both “pro‐growth” MSAs and “highly regulated” MSAs. Among all of our sample MSAs, we also find a declining share of Census tracts that participate in accommodating growth. Our results are consistent with the existence of a convex housing supply curve. We believe that this secular trend will pose genuine challenges to many urban housing policies aimed at improving affordability.

Regional-scale fault-to-structure earthquake simulations with the EQSIM framework: Workflow maturation and computational performance on GPU-accelerated exascale platforms

Continuous advancements in scientific and engineering understanding of earthquake phenomena, combined with the associated development of representative physics-based models, is providing a foundation for high-performance, fault-to-structure earthquake simulations. However, regional-scale applications of high-performance models have been challenged by the computational requirements at the resolutions required for engineering risk assessments. The EarthQuake SIMulation (EQSIM) framework, a software application development under the US Department of Energy (DOE) Exascale Computing Project, is focused on overcoming the existing computational barriers and enabling routine regional-scale simulations at resolutions relevant to a breadth of engineered systems. This multidisciplinary software development—drawing upon expertise in geophysics, engineering, applied math and computer science—is preparing the advanced computational workflow necessary to fully exploit the DOE’s exaflop computer platforms coming online in the 2023 to 2024 timeframe. Achievement of the computational performance required for high-resolution regional models containing upward of hundreds of billions to trillions of model grid points requires numerical efficiency in every phase of a regional simulation. This includes run time start-up and regional model generation, effective distribution of the computational workload across thousands of computer nodes, efficient coupling of regional geophysics and local engineering models, and application-tailored highly efficient transfer, storage, and interrogation of very large volumes of simulation data. This article summarizes the most recent advancements and refinements incorporated in the workflow design for the EQSIM integrated fault-to-structure framework, which are based on extensive numerical testing across multiple graphics processing unit (GPU)-accelerated platforms, and demonstrates the computational performance achieved on the world’s first exaflop computer platform through representative regional-scale earthquake simulations for the San Francisco Bay Area in California, USA.

Analysis of Trends in the Distance of Wildfires from Built-Up Areas in Spain and California (USA): 2007–2015

Wildfires present a significant risk to societies globally due to population growth, concentrated activities, climate change, and extreme environmental conditions. To establish effective fire suppression and management policies, it is crucial to determine whether the distance between ignition points and urban areas is increasing or decreasing. This study analyzes 101,597 fires in Spain and California between 2007 and 2015, where ignition points and all built-up areas were precisely geolocated in 2014. The study employs the Mann–Kendall test to determine trends and analyze the relative distance of wildfires to human buildings over time. The results indicate that wildfires are becoming statistically significantly closer in several areas. It is also observed that the majority of wildfires are moving away from buildings, although this is not a significant finding. These results suggest the possibility of further research into the reasons behind these observations and possible future developments and their consequences.

A Case Study and Numerical Modeling of Post-Wildfire Debris Flows in Montecito, California

Wildfires and their long-term impacts on the environment have become a major concern in the last few decades, in which climate change and enhanced anthropogenic activities have gradually led to increasingly frequent events of such hazards or disasters. Geological materials appear to become more vulnerable to hazards including erosion, floods, landslides and debris flows. In the present study, the well-known 2017 wildfire and subsequent 2018 debris flows in the Montecito area of California are examined. It is found that the post-wildfire debris flows were initiated from erosion and entrainment processes and triggered by intense rainfall. The significant debris deposition in four major creeks in this area is investigated. Numerical modeling of the post-wildfire debris flows is performed by employing a multi-phase mass flow model to simulate the growth in the debris flows and eventual debris deposition. The debris-flow-affected areas estimated from the numerical simulations fairly represent those observed in the field. Overall, the simulated debris deposits are within 7% error of those estimated based on field observations. A similar simulation of the pre-wildfire scenario indicates that the debris would be much less significant. The present study shows that proper numerical simulations can be a promising tool for estimating post-wildfire erosion and the debris-affected areas for hazard assessment and mitigation.

545 Factors that impact the success of community-engaged research: perspectives from experienced researchers and community partners

OBJECTIVES/GOALS: Involving community partners in translational research improves impact. Yet, community-engaged research is challenging, and teams vary in their success. This study builds the evidence of key barriers and facilitators to effective community-engaged team science by drawing on the perspectives of seasoned researchers and community partners. METHODS/STUDY POPULATION: We conducted 3 focus groups with academic researchers (n=9) and 2 focus groups with community research partners (n=8). All participants were adults from the Southern California area, and had experience working on research teams that included academics and community partners. The focus group guide included questions about the participant’s experience with community-engaged research, including the value of these partnerships, examples of success and challenges, and opportunities for improvement. Transcriptions of the focus group recordings were analyzed to identify key themes and insights, and to explore similarities and differences between academic and community participant perspectives. RESULTS/ANTICIPATED RESULTS: Both researchers and community partners saw the potential value of participating in community-engaged research. However, they identified challenges to address, including: 1) Community partners should be invited to participate in early stages of the research process as equal partners to help frame the objectives. 2) Community partner’s knowledge should be valued through the use of their ideas and input, and providing monetary compensation for their time. 3) Academic researchers should aim to build long-term meaningful relationships with the community and build cultural competency (language, culture, and trust). 4) Community partners should be closely involved with the interpretation of results to confirm accuracy and identify valuable insights, and these contributions should be acknowledged. DISCUSSION/SIGNIFICANCE: Community partners being undervalued is a central challenge of community-engaged research teams. Greater adoption of best practices in team science could empower community partners and increase the value of this research. Structural barriers related to research funding and academic promotion should align to support these efforts.

Investigation of the use of topographic data derived from Pléiades imagery for high-resolution hillslope-scale morphometry

Obtaining accurate representations of the Earth surface topography is paramount in many geomorphological investigations. While regional scale studies use Digital Elevation Models (DEM) with resolution of the order of 10–100 m, in many applications resolution <5 m are mandatory to appropriately represent landforms and processes of interest. In particular, hillslopes, which cover the most of continental surfaces, have typical length of the order of 100 m. For that reason, high resolution topographic data are mandatory to correctly represent their morphology. The massive use of higher resolution topographic data has been enabled by a vast array of methodological developments, among which terrestrial and airborne Light Detection And Ranging (LiDAR) or uncrewed aerial vehicle-based photogrammetric approaches are the most commonly used. However, such techniques might be difficult to deploy and not cost-effective, to cover large areas in remote locations.In this study, we present an exploration of the potential of topographic data derived from Pléiades imagery for the characterizing hillslope morphology. We focus on the Gabilan Mesa area in California, where a LiDAR DEM is available and is used as a benchmark. We systematically compare Pléiades-derived topographic data with the DEM constructed from LiDAR data, starting from simple elevation analysis and then using topographic derivatives, such as slope or curvature, which are commonly used in morphometric studies. Finally, we take advantage of the high resolution of the datasets to extract and compare hillslope-scale morphometric parameters, such as length, relief, or hilltop curvature. While some particular situations, such as planar and horizontal surfaces, requires specific attention in terms of the relative differences between the two type of data, the absolute values for the metrics are in good agreement over their relevant range of utilization for hillslope-scale geomorphology.

Less is more: Fewer attract-and-kill sites improve the male annihilation technique against Bactrocera dorsalis (Diptera: Tephritidae).

The Male Annihilation Technique (also termed the Male Attraction Technique; "MAT") is often used to eradicate pestiferous tephritid fruit flies, such as Bactrocera dorsalis (Hendel). MAT involves the application of male-specific attractants combined with an insecticide in spots or stations across an area to reduce the male population to such a low level that suppression or eradication is achieved. Currently, implementations of MAT in California and Florida targeting B. dorsalis utilize the male attractant methyl eugenol (ME) accompanied with a toxicant, such as spinosad, mixed into a waxy, inert emulsion STATIC ME (termed here "SPLAT-MAT-ME"). While highly effective against ME-responding species, such applications are expensive owing largely to the high cost of the carrier matrix and labor for application. Until recently the accepted protocol called for the application of approximately 230 SPLAT-MAT-ME spots per km2; however, findings from Hawaii suggest a lower density may be more effective. The present study adopted the methods of that earlier work and estimated kill rates of released B. dorsalis under varying spot densities in areas of California and Florida that have had recent incursions of this invasive species. Specifically, we directly compared trap captures of sterilized marked B. dorsalis males released in different plots under three experimental SPLAT-MAT-ME densities (50, 110, and 230 per km2) in Huntington Beach, CA; Anaheim, CA; and Sarasota-Bradenton, FL. The plots with a density of 110 sites per km2 had a significantly higher recapture proportion than plots with 50 or 230 sites per km2. This result suggests that large amounts of male attractant may reduce the ability of males to locate the source of the odor, thus lowering kill rates and the effectiveness of eradication efforts. Eradication programs would directly benefit from reduced costs and improved eradication effectiveness by reducing the application density of SPLAT-MAT-ME.

Data-driven identification of earthquake clusters: Clusters before the 2010 El mayor-Cucapah earthquake MW 7.1, Baja California, Mexico

Seismic clusters in background seismicity have been associated with high stress levels and can be an important precursor to large earthquakes, but there is not a unanimous concept of cluster and most cluster identification methods are cumbersome and involve a priori assumptions. We propose a simple definition of seismic cluster and a straightforward method of identification involving a minimum of parameters that can be objectively determined in a data-driven way according to a principle of low random occurrence. As an illustration, definition and method were applied to the identification of cluster activity from October 1979 to March 2010 in northern Baja California, Mexico, between 118°W to 113°W and 30°N to 33°N, a tectonically complex seismic region with several fault systems. Twenty-one clusters were identified, of which 17 located around the places at the northeastern corner of the study area that would be ruptured on April 4, 2010 by the El Mayor-Cucapah Mw 7.1 earthquake, the largest recorded earthquake in Baja California, Mexico, and the four others occurred within 9 km from its epicenter. Clustering also became slightly more frequent as the time of the earthquake approached, so that if the clustering survey had been carried out before the whole northern Baja California area, the clustering might have identified the future epicentral region as a region of interest to be closely monitored (this earthquake featured foreshock activity starting some 15 days before the main event). Although the reliability of clusters as precursors to large earthquakes is still to be studied, it is certainly useful to have a reliable and simple method to identify and characterize them.

A Comprehensive Assessment of Submarine Landslides and Mass Wasting Processes Offshore Southern California

AbstractIt is critical to characterize submarine landslide hazards near dense coastal populations, especially in areas with active faults, which can trigger slope failure, subsequent tsunamis, and damage seabed infrastructure during earthquake shaking. Offshore southern California, numerous marine geophysical surveys have been conducted over the past decade, and high‐resolution bathymetric and subsurface data now cover about 60 percent of the total region between Point Conception and the United States‐Mexico border from the California coast out to the base of Patton Escarpment ∼200 km offshore. In a comprehensive compilation and interpretive mapping effort, we find evidence of seafloor failure throughout offshore southern California with nearly 1,500 submarine landslide‐related features, including 63 discrete slide deposits with debris and &gt;1,400 slide‐related scarps. In our analysis, we highlight new mapping of submarine landslides in Catalina Basin, the Del Mar slide, the San Gabriel slide complex, and the 232 km2 San Nicolas slide, the largest area of any known submarine landslide mass offshore southern California. Analysis of the spatial distribution of submarine landslide features suggests that most mapped slide features are located relatively near coastal sediment sources, particularly during sea‐level lowstand conditions, which underscores the importance of sediment supply and sediment accumulation on low‐gradient slopes as failure preconditioning processes. Tectonically driven uplift at shelf edges and along basin flanks is another key preconditioning factor, and our results also suggest that earthquakes along active faults trigger mass wasting, especially for repeated, small‐scale failures on tectonically steepened slopes.

Revisiting day-of-week ozone patterns in an era of evolving US air quality

Abstract. Past work has shown that traffic patterns in the USA and resulting NOx emissions vary by day of week, with NOx emissions typically being higher on weekdays than weekends. This pattern of emissions leads to different levels of ozone on weekends versus weekdays and can be leveraged to understand how local ozone formation changes in response to NOx emission perturbations in different urban areas. Specifically, areas with lower NOx but higher ozone on the weekends (the weekend effect) can be characterized as NOx-saturated and areas with both lower NOx and ozone on weekends (the weekday effect) can be characterized as NOx-limited. In this analysis, we assess maximum daily 8 h average (MDA8) ozone weekend–weekday differences across 51 USA nonattainment areas using 18 years of observed and modeled data from 2002–2019, using the following two metrics: mean MDA8 ozone and percentage of days with MDA8 ozone &gt; 70 ppb (parts per billion). In addition, we quantify the modeled and observed trends in these weekend–weekday differences across this period of substantial NOx emission reductions in the USA. The model assessment is carried out using U.S. Environmental Protection Agency (EPA)'s Air QUAlity TimE Series Project (EQUATES) Community Multiscale Air Quality (CMAQ) model dataset. We identify three types of MDA8 ozone trends occurring across the USA, namely transitioning chemical regime, disappearing weekday effect, and no trend. The transitioning chemical regime trend occurs in a subset of large urban areas that were NOx-saturated (i.e., volatile organic compound (VOC)-limited) at the beginning of the analysis period but transitioned to mixed chemical regimes or NOx-limited conditions by the end of the analysis period. Nine areas have strong transitioning chemical regime trends using both modeled and observed data and with both metrics indicating strong agreement that they are shifting to more NOx-limited conditions: Milwaukee, Houston, Phoenix, Denver, the Northern Wasatch Front, the Southern Wasatch Front, Las Vegas, Los Angeles – San Bernardino County, Los Angeles – South Coast, and San Diego. The disappearing weekday effect was identified for multiple rural and agricultural areas of California which were NOx-limited for the entire analysis period but appear to become less influenced by local day-of-week emission patterns in more recent years. Finally, we discuss a variety of reasons why there are no trends in certain areas including complex impacts of heterogeneous source mixes and stochastic impacts of meteorology. Overall, this assessment finds that the EQUATES modeling simulations indicate more NOx-saturated conditions than the observations but do a good job of capturing year-to-year changes in weekend–weekday MDA8 ozone patterns.