Search

Daniela Ponce,1 Welder Zamoner,1 Luis Eduardo Magalhães,1 Paula Gabriela Sousa de Oliveira,1 Patricia Polla,2 Alexandre Naime Barbosa,3 Marjorie de Assis Golim,2 André Luís Balbi Snr1 1Department of Internal Medicine, University Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil; 2Clinical Hospital of Botucatu Medical School, Botucatu, São Paulo, Brazil; 3Department of Infectious Disease, University Estadual Paulista (UNESP), Botucatu, São Paulo, BrazilCorrespondence: Daniela Ponce, Department of Internal Medicine – UNESP, Univ Estadual Paulista, Rubião Jr, s/n, Botucatu, SP, 18.618-970, Brazil, Tel/Fax +55 14 3811-6000, Email daniela.ponce@unesp.brBackground: In the absence of direct therapy for COVID-19, extracorporeal blood treatment (EBT) could represent an option for cytokine removal.Objective: This study aimed to describe and compare cytokine removal during intermittent haemodialysis (IHD) and continuous renal replacement therapy (CRRT) in COVID-19 patients with Acute Kidney Injury (AKI).Methods: It was a cohort study that studied patients with COVID-19-related AKI according to KDIGO criteria and admitted at Intensive Care Unit (ICU). Blood samples were collected at the start and end of both IHD using high flux (HF) membranes (10 patients) and continuous venovenous haemodiafiltration (CVVHDF:10 patients) in two sessions for measuring 13 different plasma interleukins and calculating the cytokine removal rate.Results: There was no difference between the two groups regarding mechanical ventilation, vasoactive drug, age or prognostic scores. Patients treated by CRRT presented higher levels of IL-2 and IL-8 than patients treated by IHD at dialysis start. Cytokine removal ranged from 9% to 78%. Patients treated by CRRT presented higher cytokine removal for IL-2, IL-6 IL-8, IP-10 and TNF. The removal rates of IL-4, IL-10, IL-17A, IFN, MCP-1 and TGF-B1 were similar in two groups. After one session of CVVHDF (24 h), IL-2 and IL-1β levels did not vary significantly, whereas IL-4, IL-6, IL-8, IL-10, IL-17A, TNF, IFN, IP-10, MCP-1, IL-12p70 and TGF-B1 decreased by 33.8– 76%, and this decrease was maintained over the next 24 h. In IHD groups, IL-2, IL-6, TNF, IP-10 and IL-1β levels did not decrease significantly whereas IL-4, IL-8, IL-10, IL-17A, IFN, MCP-1, IL-12p70 and TGF-B1 decreased by 21.8– 72%; however, cytokine levels returned to their initial values after 24 h.Conclusion: Cytokine removal is lower in IHD using HF membranes than in CVVHDF, and in IHD the removal is transient and selective, which can be associated with mortality during cytokines storm-related COVID-19.Keywords: cytokine storm, removal, EBP

Daniela Ponce,1,2 Welder Zamoner,2 Vanessa Addad,1 Marci Maria Batistoco,2 André Balbi1,2 1Internal Department, University State of Sao Paulo- UNESP, Botucatu, Sao Paulo, Brazil; 2Clinical Hospital of Botucatu Medical School, Botucatu, Sao Paulo, BrazilCorrespondence: Daniela Ponce Email daniela.ponce@unesp.brIntroduction: Acute renal replacement therapy (RRT) is indicated when metabolic and fluid demands exceed total kidney capacity, and demand for kidney function is determined by non-renal comorbidities, severity of acute disease and solute and fluid burden; therefore, the criteria for commencing RRT and dialysis in intensive care units (ICUs) may be different to those outside ICUs.Objective: We investigated whether criteria for commencing acute RRT and dialysis outside ICU were different to those in ICU and whether these differences affected patient mortality in either setting.Methods: We performed a retrospective observational study evaluating acute kidney injury (AKI), Kidney Disease Improving Global Outcome 3 (KDIGO3) in adult patients undergoing RRT “in and outside” ICU from 2012 to 2018, in a Brazilian teaching hospital.Results: We evaluated 913 adults with AKI KDIGO3 undergoing RRT; 629 (68.9%) outside ICU and 284 (31.1%) in ICU. Infections were the main cause of hospitalisation (34.4%). Septic and ischaemic AKI were the main aetiologies of AKI (50.8% and 32.9%, respectively), metabolic and fluid demand to capacity imbalance were the main indications for dialysis (69.7%), and intermittent haemodialysis (IHD) was the primary dialysis method (59.2%). The general mortality rate after 30 days was 59%. There were no differences in gender, age and main diagnosis between groups. Both groups were different in acute tubular necrosis index specific scores (ATN-ISS), AKI aetiology, elderly population, indications for dialysis, dialysis methods and mortality rates. In ICU, patients older than 65 years old, with septic AKI were more prevalent (49.1 versus 41.4%, and 55.1 versus 37.5%, respectively), while ischaemic and nephrotoxic AKI were less frequent (24.3 versus 37 and 10.2 versus 16.3%, respectively), and ATN-ISS was higher (0.74 ± 0.31 versus 0.58 ± 0.16). Similarly, metabolic and fluid demand to capacity imbalance as an indication for acute RRT, prolonged intermittent haemodialysis (PIRRT) and continuous renal replacement therapy (CRRT) were more frequent, while peritoneal dialysis (PD) was less frequent (74.6 versus 69.7%, 31.6 versus 22.4%, and 5.3 versus 17.8%, respectively), and mortality was higher (69 versus 54.7%, respectively). Logistic regression revealed that age, septic AKI and being “in” ICU were factors associated with death.Conclusion: The criteria for commencing RRT and dialysis in ICU were different to those outside ICU; however, they did not impact on patient outcomes.Keywords: acute kidney injury, acute dialysis, mortality

Welder Zamoner,1 Isabella Gonçalves Pierri,1 Karina Zanchetta Cardoso Eid,1 Lais Maria Bellaver de Almeida,1 Adriano dos Santos,2 André Luís Balbi,1 Daniela Ponce1 1Botucatu School of Medicine, São Paulo State University - UNESP, Botucatu, São Paulo, Brazil; 2Clinics Hospital Pharmacy, Botucatu School of Medicine, Botucatu, São Paulo 18618-970, BrazilCorrespondence: Welder Zamoner Tel +55 14 9821 72334Email welder.zamoner@unesp.brIntroduction and Aim: There have been few studies to evaluate the monitoring of plasmatic concentrations of vancomycin in septic patients and their association with acute kidney injury (AKI) and death. This study aimed to evaluate the prevalence of adequate, subtherapeutic, and toxic serum concentrations of vancomycin in hospitalized septic patients and to associate the adequacy of therapeutic monitoring with clinical outcomes.Methodology: This was a cohort-unicentric study that evaluated septic patients aged > 18 years using vancomycin admitted to clinical and surgical wards of a Brazilian university center from August 2016 to July 2017 in a daily and uninterrupted way. We excluded patients with AKI prior to the introduction of vancomycin or with AKI development < 48 hours after use, patients with AKI of other etiologies, stage V chronic kidney disease, and pregnant women.Results: We evaluated 225 patients, and 135 were included. Evaluation of serum concentration of vancomycin was realized in 94.1%, and of those, 59.3% presented toxic concentrations. The prevalence of AKI was 27.4% and happened on average on the ninth day of vancomycin usage. Between the fourth and sixth days, vancomycin serum concentration of > 21.5 mg/L was a predictor of AKI, with area under the curve of 0.803 (95% CI 0.62– 0.98, p=0.005), preceding the diagnosis of AKI by at least 3 days. Of these patients, 20.7% died, and serum concentrations of vancomycin between the fourth and sixth days were identified as risk factors associated with negative outcomes.Conclusion: Serum concentration of vancomycin is an excellent predictor of AKI in patients admitted to wards, preceding the diagnosis of AKI by at least 72 hours. Toxic concentrations of vancomycin are associated with AKI, and AKI was a risk factor for death. Also, serum concentration of vancomycin > 21.5 mg/L was the only variable associated with death in the Cox model.Keywords: sepsis, acute kidney injury, vancomycin, nephrotoxicity

Laís Gabriela Yokota,1 Beatriz Mota Sampaio,1 Erica Pires Rocha,1 André Luís Balbi,1 Iara Ranona Sousa Prado,1 Daniela Ponce1,2 1Botucatu School of Medicine, São Paulo State University (UNESP), Sao Paulo, Brazil; 2Course of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil Abstract: Acute kidney injury (AKI) is characterized by a sudden renal dysfunction with consequent increase of nitrogenous products, hydroelectrolytic and acid–base disorders. Its prevalence is high in hospitalized populations (4.9%–7.2%), especially in intensive care units (ICUs). Despite all the technical and therapeutic advances that have occurred in the last few decades, the overall mortality of AKI patients remains high, reaching 80% in ICU patients. Several conditions predispose a patient to progress with AKI, including age, sepsis, surgeries, and comorbidities, such as systemic arterial hypertension, diabetes mellitus, heart disease, neoplasia, and chronic renal disease. Among these risk factors, age is emphasized, since, due to advances in the health area, there has been an increase in life expectancy, hence an increase in the demand of the elderly population for health services. At the same time, the elderly present a greater predisposition to the development of AKI, either due to kidney senility, or because of the high prevalence of comorbidities present, and medical interventions such as the use of contrasts and medications, which can also trigger AKI. Considering the relevance of the social role of the elderly and the scarcity of studies on AKI in the elderly admitted to the ICU, further studies are needed. This review article was elaborated considering the purpose: to assess incidence, risk factors, and mortality of AKI in elderly patients admitted to ICUs. Published studies were collected using the following inclusion criteria: be accessible in online databases (Lilacs, Scielo, and PubMed), have been published since 2000 and written in English, Portuguese, or Spanish. The descriptors used for the survey were “Acute Kidney Injury”, “Aging”, and “Elderly”. All items that did not fit in the above inclusion criteria were discarded. We have also presented a synthesis of the knowledge acquired during this review. Keywords: comorbidities, risk factors, elderly, acute kidney injury, mortality, intensive care unit

Occurrences of alkaline and carbonatite rocks with high concentrations of rare earth elements (REE) are a defining feature of Precambrian geology in the Mojave Desert of southeastern California. The most economically important occurrence is the carbonatite stock at Mountain Pass, which constitutes the largest REE deposit in the United States. A central scientific goal is to understand the genesis of the carbonatite ore body in the context of widespread REE‐rich igneous activity. A swarm of mafic alkaline (shonkinite) dikes has been mapped and sampled at Bobcat Hills, 65 km southeast of the Mountain Pass mine. Whole‐rock geochemistry and zircon geochronology demonstrate a clear affinity to the ca. 1.4 Ga Mountain Pass intrusive system. Bobcat Hills dikes have comparably high REE concentrations (La ∼1,000× chondritic) and an error‐weighted mean 207Pb/206Pb zircon crystallization age of 1,426 ± 2 Ma (2σ). Unlike the alkaline intrusions at Mountain Pass, which have abundant inherited zircon from Paleoproterozoic basement rocks and crustally influenced oxygen isotope compositions (δ18Ozircon = 6.5–7.5‰), the Bobcat Hills dikes lack any evidence of crustal assimilation and have oxygen isotope values that overlap a mantle range (Bobcat Hills average δ18Ozircon = 5.6 ± 0.3‰). The dikes were a high‐temperature, early center of mafic alkaline magmatism in the Mojave Desert that serve as a snapshot of melt generation from a spatially extensive, metasomatized mantle source. We propose that modification of the crust over many tens of Myr at Mountain Pass created an environment that favored crustal assimilation and enabled ascent of late‐stage, REE‐rich carbonatite magmas. Key Points: The Bobcat Hills site expands the distribution of REE‐rich mafic alkaline magmatism 65 km southeast of the Mountain Pass mineShonkinite dikes at Bobcat Hills are physically and chemically similar to mafic intrusions at Mountain Pass and have comparably high REEBobcat Hills was an early center of REE‐rich magmatism in the Mojave Desert, with a zircon U‐Pb crystallization age of 1,426 ± 2 Ma [ABSTRACT FROM AUTHOR]

Laís Gabriela Yokota, Beatriz Motta Sampaio, Erica Rocha, André Luís Balbi, Daniela Ponce Internal Medicine Department, University São Paulo State-UNESP, Distrito de Rubiao Junior, Botucatu, Sao Paulo, Brazil Aim: The elderly are at high risk of acute kidney injury (AKI) because of structural and functional degeneration over time and with the aging of the population, the demand for intensive care unit (ICU) admission for older patients has risen recently. However, data from developing countries are scarce. This study aimed to describe the incidence of AKI in elderly patients admitted to ICU from a developing country, to determine the most frequent etiologies for renal impairment and identify its risk factors and outcome. Methods: All patients admitted to the ICU at a Brazilian teaching hospital for 12 consecutive months were followed prospectively from the time of admission until ICU discharge. Elderly was defined as aged >60 years and AKI was defined according to the Kidney Disease Improving Global Outcomes 2012 criteria. Multivariable logistic regression was used to adjust confounding and selection bias. Results: Two hundred elderly patients were included in the study. AKI incidence was 27% and the main etiology was sepsis (48.1%). At logistic regression, baseline creatinine (odds ratio [OR]=5.17, p

Daniela Ponce, Andre Balbi Department of Medicine, Botucatu School of Medicine, Sao Paulo, Brazil Abstract: Acute kidney injury (AKI) is a major global health problem in both developed and developing nations, negatively affecting patient morbidity and responsible for an estimated 1.4 million deaths per year. Although the International Society of Nephrology set a goal of eliminating preventable deaths from AKI by 2025, implementation of this program in developing countries presents major challenges not only because of the lack of resources but also because of the scarce data addressing the epidemiology and causes of AKI in developing countries, the limited health care resources to diagnose and treat AKI, and the poor awareness of the impact of AKI on patient outcomes. Keywords: acute kidney injury, developing world, treatment

Copyright of International Journal of Medicine & Science of Physical Activity & Sport / Revista Internacional de Medicina y Ciencias de la Actividad Física y del Deporte is the property of Revista Internacional de Medicina y Ciencias de la Actividad Fisica y del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Theophylline is a drug widely known for treating asthma and sorne other chronic respiratory diseases. At present time,the blood levels of drugs can be related with eficacy and side effects. There are around 10 drug products ofprogrammedrelease theophyIline forms, commercially available in Colombia. Most of the problems found in the utilization are caused by the non advisable interchange of theophyIline drug products, without any bioequivalency data for them. This study proposes a specific and validated analytical methodology for theophylline in biological fluid s including blood, which is useful for bioavailability and bioequivalencystudies, rutinary monitoring of theophylline blood levels and in forensic chemistry. This metodology has the advantage. touse a mobile phase les s contaminant and cheaper than others previously used. Besides, it makes easier the cleaning of the equipment and extend the useful life of the column. The chromatographic separation system by HPLC-RP, with spectrophotometric detection at 266 nm, ineludes an octadecylsilane C-18 column, and methanol/water as mobile phase.

La planificación de la producción en pequeñas empresas es un problema habitual, ya que muchas veces el o los ingenieros no cuentan con el tiempo o las herramientas apropiadas para hacer una buena gestión de la producción. Actualmente, los computadores personales permiten aplicar metodologías de planificación, reduciendo sofisticados problemas en simples estructuras de datos, con apoyo visual de gráficos y tablas, lo que conlleva a un mejor control, tanto de la producción como de los costos. El estudio de caso presentado corresponde al tipo de estas empresas, productora de madera aserrada de pino radiata, en la cual se aplicó una planificación agregada (PA). Se utilizaron datos del último año de producción, y se evaluaron cuatro estrategias productivas relacionadas con la fuerza laboral, el nivel de inventario, de producción y de demanda. Los resultados llevan a concluir que el método propuesto es recomendable para empresas del tamaño estudiado, ya que se puede aplicar fácilmente y permite una adecuada gestión. Con la elección empresarial elegida, fue posible reducir los costos de producción, asegurando políticas laborales y se manejó adecuadamente el nivel de inventario; se redujo en un 1,92% el costo por pulgada producida, ahorrando la empresa más de 6 millones de pesos anuales.The planning of the production in small-scale industries is a usual problem. Since most of the time, engineers are not provided with the time or the appropriate hardware to do a good management of the production. At the time, personal computers allow to apply methodologies of planning, reducing sophisticated problems in simple structures of data, with visual support of graphs and sheet work, which it bears to a better control, both in the production as it is costs. The study case presented corresponds to the type of these industries, producer of saw wood radiate pine, in which an aggregate production (AP) was applied. There was used information from last year´s production, and there were evaluated four productive strategies related to the labor force, the inventory level, production and demand. The results lead to conclude that the proposed method is advisable for companies of the studied size, since it possible to apply easily and allows an appropriate management. With the managerial elected election, it was possible to reduce the costs production, assuring political labor and an appropriately inventory level; the cost diminished in 1.92% for produced inch, saving the company more than 6 million Chilean pesos annual.

Se analiza la competitividad en los principales mercados de las exportaciones chilenas de madera aserrada de pino radiata en el período 1994-2004 (Contreras, 2006). Se aplica la metodología "Competitive Análisis of Nation" (CAN), creada por la Comisión Económica para América Latina y el Caribe (CEPAL), que permite obtener una visión dinámica de las situaciones de competitividad del producto en los mercados estudiados. Los resultados se compararon con un estudio similar del periodo 1987 a 1997, realizado por Fuenzalida (1999). El análisis de la competitividad en el periodo 1994-2004 muestra que el producto tiene una posición competitiva de Estrella Naciente, en los mercados de China, España, Estados Unidos. y Marruecos; de Estrella Menguante en los mercados de México y Canadá; de Oportunidad Perdida en Japón, Arabia Saudita y Reino Unido; y de Retroceso, en Corea del Sur. Por otro lado, comparando los dos periodos en estudio, se encontró que los mercados de Estados Unidos, Corea del Sur, Japón, Reino Unido y Arabia Saudita, que se repiten en ambos periodos, disminuyeron su posición competitiva del primer periodo al segundo. Asimismo, se puede concluir que el comercio mundial de productos forestales creció más que el comercio de madera aserradaThe competitiveness is analyzed on the principal markets of the Chilean exports of saw wood of radiata pine in the period 1994-2004 (Contreras, 2006). The methodology applied is "Competitive Analysis of Nation" (CAN), created by the Economic Commission for Latin America and the Caribbean (CEPAL), who allows to obtain a dynamic vision of the situations of competitiveness of the product on the studied markets. The results were compared with a similar study of the period 1987 to 1997 realized by Fuenzalida (1999). The analysis of the competitiveness in the period proves to be 1994-2004 that the product has Nascent Start’s competitive position, on the markets of China, Spain, United States and Morocco; of Waning Start’s position on the markets of Mexico and Canada; of Lost Opportunity in Japan, Saudi Arabia and United Kingdom; and of Setback in South Korea. On the other hand, comparing both periods, one thought that the markets of United States, South Korea, Japan, United Kingdom and Saudi Arabia, which they repeat in both periods, diminished their competitive position of the first period to the second one. Likewise, it is possible to conclude that the world trade of forest products grew more than the trade than saw wood

La planificación de la producción en pequeñas empresas es un problema habitual, ya que muchas veces el o los ingenieros no cuentan con el tiempo o las herramientas apropiadas para hacer una buena gestión de la producción. Actualmente, los computadores personales permiten aplicar metodologías de planificación, reduciendo sofisticados problemas en simples estructuras de datos, con apoyo visual de gráficos y tablas, lo que conlleva a un mejor control, tanto de la producción como de los costos. El estudio de caso presentado corresponde al tipo de estas empresas, productora de madera aserrada de pino radiata, en la cual se aplicó una planificación agregada (PA). Se utilizaron datos del último año de producción, y se evaluaron cuatro estrategias productivas relacionadas con la fuerza laboral, el nivel de inventario, de producción y de demanda. Los resultados llevan a concluir que el método propuesto es recomendable para empresas del tamaño estudiado, ya que se puede aplicar fácilmente y permite una adecuada gestión. Con la elección empresarial elegida, fue posible reducir los costos de producción, asegurando políticas laborales y se manejó adecuadamente el nivel de inventario; se redujo en un 1,92% el costo por pulgada producida, ahorrando la empresa más de 6 millones de pesos anuales. Abstract The planning of the production in small-scale industries is a usual problem. Since most of the time, engineers are not provided with the time or the appropriate hardware to do a good management of the production. At the time, personal computers allow to apply methodologies of planning, reducing sophisticated problems in simple structures of data, with visual support of graphs and sheet work, which it bears to a better control, both in the production as it is costs. The study case presented corresponds to the type of these industries, producer of saw wood radiate pine, in which an aggregate production (AP) was applied. There was used information from last year´s production, and there were evaluated four productive strategies related to the labor force, the inventory level, production and demand. The results lead to conclude that the proposed method is advisable for companies of the studied size, since it possible to apply easily and allows an appropriate management. With the managerial elected election, it was possible to reduce the costs production, assuring political labor and an appropriately inventory level; the cost diminished in 1.92% for produced inch, saving the company more than 6 million Chilean pesos annual.

Se analiza la competitividad en los principales mercados de las exportaciones chilenas de madera aserrada de pino radiata en el período 1994-2004 (Contreras, 2006). Se aplica la metodología “Competitive Análisis of Nation” (CAN), creada por la Comisión Económica para América Latina y el Caribe (CEPAL), que permite obtener una visión dinámica de las situaciones de competitividad del producto en los mercados estudiados. Los resultados se compararon con un estudio similar del periodo 1987 a 1997, realizado por Fuenzalida (1999). El análisis de la competitividad en el periodo 1994- 2004 muestra que el producto tiene una posición competitiva de Estrella Naciente, en los mercados de China, España, Estados Unidos. y Marruecos; de Estrella Menguante en los mercados de México y Canadá; de Oportunidad Perdida en Japón, Arabia Saudita y Reino Unido; y de Retroceso, en Corea del Sur. Por otro lado, comparando los dos periodos en estudio, se encontró que los mercados de Estados Unidos, Corea del Sur, Japón, Reino Unido y Arabia Saudita, que se repiten en ambos periodos, disminuyeron su posición competitiva del primer periodo al segundo. Asimismo, se puede concluir que el comercio mundial de productos forestales creció más que el comercio de madera aserrada. Abstract The competitiveness is analyzed on the principal markets of the Chilean exports of saw wood of radiata pine in the period 1994-2004 (Contreras, 2006). The methodology applied is “Competitive Analysis of Nation” (CAN), created by the Economic Commission for Latin America and the Caribbean (CEPAL), who allows to obtain a dynamic vision of the situations of competitiveness of the product on the studied markets. The results were compared with a similar study of the period 1987 to 1997 realized by Fuenzalida (1999). The analysis of the competitiveness in the period proves to be 1994-2004 that the product has Nascent Start’s competitive position, on the markets of China, Spain, United States and Morocco; of Waning Start’s position on the markets of Mexico and Canada; of Lost Opportunity in Japan, Saudi Arabia and United Kingdom; and of Setback in South Korea. On the other hand, comparing both periods, one thought that the markets of United States, South Korea, Japan, United Kingdom and Saudi Arabia, which they repeat in both periods, diminished their competitive position of the first period to the second one. Likewise, it is possible to conclude that the world trade of forest products grew more than the trade than saw wood.

Microtremor measurements were performed on four historical timber–masonry composite pagodas (called tiered temples) in Kathmandu Valley. Several measurements were performed between 2009 and 2017. The Gorkha earthquake occurred on April 25, 2015, causing severe damage (collapse, inclination, uplifting of the top tier, and damage to masonry walls) to the temples being monitored. The earthquake damage was assessed, and the results were compared with the structures' fundamental vibration characteristics, determined using microtremor measurements. The temples, which were surveyed before and after the earthquake, exhibited an increase in the natural period of vibration and a stiffness loss of approximately 10%. For the four temples with multiple tiers investigated, linear idealisation of the natural period of vibration with the height of the structure is proposed. By including microtremor measurements conducted in previous studies, the natural periods of the tiered temples in Nepal were found to be distributed between 0.3 and 0.7 s. [ABSTRACT FROM AUTHOR]

The gyrotron installation on the DIII-D tokamak has been in operation at the second harmonic of the electron cyclotron resonance since the mid-1990s. Prior to that a large installation of ten 60 GHz tubes was operated at the fundamental resonance. The system has been upgraded regularly and is an everyday tool for experiments on DIII-D.

The Sulphide Queen carbonatite deposit at Mountain Pass in southeast California is a world class rare earth element (REE) resource. This study images electrical resistivity structure of the REE deposit and surrounding area to characterize resources under cover. An east-west elongated grid (35 × 15 km) of 65 wideband magnetotelluric stations spanning from eastern Shadow Valley to eastern Ivanpah Valley were collected and modeled in three-dimensions (3-D). Gravity, aeromagnetic, and geologic data are used to inform interpretation of structures in the resistivity model, including the following observations. Shadow Valley is filled with conductive sediment that locally dips southward to a depth of 1 km. The Kingston Range-Halloran Hills detachment fault dips westward at ~15 degrees. The REE deposit is a moderate low resistivity zone dipping southwest to a possible depth of ~1 km, and is bounded by the North and South faults and bisected by the Middle fault. Ivanpah Dry Lake is underlain by a north striking southward dipping sedimentary basin. Two possible zones of mineralization are observed in Ivanpah Valley, one along the western edge of Ivanpah Dry Lake and one on the western edge of valley along a new inferred fault. The brittle-ductile transition is imaged at ~10 km below mean sea level. No deep electrically conductive structures are imaged to be related to the REE deposit likely due to the complex geologic history of the Mojave terrane. Future studies should regional target Proterozoic rocks and search within for geophysical signatures similar to Mountain Pass. [ABSTRACT FROM AUTHOR]

The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras faults. Equipped with a wealth of images of this fault system, including those of its 3D geology and 3D geometry, in addition to inferences about its interseismic creep‐rate pattern and rock‐friction behavior, we use a finite‐element computer code to perform 3D dynamic earthquake rupture simulations. We find that the rock properties affect the locations and amount of slip produced in our simulated large earthquakes. Crucial factors that control rupture behavior in our modeling are the earthquake nucleation locations, the fault geometry, and the data that reveal where the fault system is creeping or locked. Our findings suggest that large Rodgers Creek‐Hayward‐Calaveras‐Northern Calaveras (RC‐H‐C‐NC) fault‐system earthquakes may result from dynamic rupture that starts in a locked part of the fault system, but is then stopped by the creeping parts, leading to high‐magnitude‐6 earthquakes; or, from dynamic rupture that starts in a locked part of the fault system, then cascades through some of the creeping parts, leading to magnitude‐7 earthquakes. Plain Language Summary: The San Francisco Bay area has experienced large earthquakes in the past and is likely to experience large earthquakes in the future. Although the San Andreas fault is the best‐known earthquake generator, other San Francisco Bay area faults, including some that slowly move (creep) all of the time are also known to be hazardous. We use computer modeling to simulate large earthquakes on the Hayward fault, and its connected companions to the north and south, the Rodgers Creek and Calaveras faults. In our computer simulations, we include information about the rock properties, rock‐friction, and fault geometry, in addition to inferences about where the faults creep. We find that the earthquake nucleation location, the fault geometry, and the pattern of fault creep, are most important. Our findings suggest that large earthquakes on these faults may result from a fast‐slipping rupture that starts in a locked part of the faults, but is then stopped by the slowly slipping parts of the faults, leading to high‐magnitude‐6 earthquakes, or, from fast‐slipping rupture that starts in a locked part of the faults, then cascades through some of the creeping‐fault parts, leading to magnitude‐7 earthquakes. Key Points: We simulated large earthquakes on the Rodgers Creek‐Hayward‐Calaveras fault system, CaliforniaOur spontaneous rupture (dynamic rupture) simulations included the 3D fault geometry, 3D rock properties, and creeping‐fault patchesThe resulting earthquakes are most affected by which fault they start on, the fault geometry, and the pattern of interseismic fault creep [ABSTRACT FROM AUTHOR]