924 research outputs found

    The Seismic Signature of Debris Flows: Flow Mechanics and Early Warning at Montecito, California

    Get PDF
    Debris flows are concentrated slurries of water and sediment that shape the landscape and pose a major hazard to human life and infrastructure. Seismic ground motion‐based observations promise to provide new, remote constraints on debris flow physics, but the lack of data and a theoretical basis for interpreting them hinders progress. Here we present a new mechanistic physical model for the seismic ground motion of debris flows and apply this to the devastating debris flows in Montecito, California on 9 January 2018. The amplitude and frequency characteristics of the seismic data can distinguish debris flows from other seismic sources and enable the estimation of debris‐flow speed, width, boulder sizes, and location. Results suggest that present instrumentation could have provided 5 min of early warning over limited areas, whereas a seismic array designed for debris flows would have provided 10 min of warning for most of the city

    The concept of diagonal approximated signature: new surrogate modeling approach for continuous-state systems in the context of resilience optimization

    Get PDF
    The increasing size and complexity of modern systems presents engineers with the inevitable challenge of developing more efficient yet comprehensive computational tools that enable sound analyses and ensure stable system operation. The previously introduced resilience framework for complex and sub-structured systems provides a solid foundation for comprehensive stakeholder decision-making, taking into account limited resources. In their work, a survival function approach based on the concept of survival signature models the reliability of system components and subsystems. However, it is limited to a binary component and system state consideration. This limitation needs to be overcome to ensure comprehensive resilience analyses of real world systems. An extension is needed that guarantees both maintaining the existing advantages of the original resilience framework, yet enables continuous performance consideration. This work introduces the continuous-state survival function and concept of the Diagonal Approximated Signature (DAS) as a corresponding surrogate model. The proposed concept is based on combinatorial decomposition adapted from the concept of survival signature. This allows for the advantageous property of separating topological and probabilistic information. Potentially high-dimensional coherent structure functions are the foundation. A stochastic process models the time-dependent degradation of the continuous-state components. The proposed approach enables direct computation of the continuous-state survival function by means of an explicit formula and a stored DAS, avoiding costly online Monte Carlos Simulation (MCS) and overcoming the limitation of a binary component and system state consideration during resilience optimization for sub-structured systems. A proof of concept is provided for multi-dimensional systems and an arbitrary infrastructure system.</jats:p

    Artery tertiary lymphoid organs control aorta immunity and protect against atherosclerosis via vascular smooth muscle cell lymphotoxin β receptors

    Get PDF
    Tertiary lymphoid organs (TLOs) emerge during nonresolving peripheral inflammation, but their impact on disease progression remains unknown. We have found in aged Apoe−/− mice that artery TLOs (ATLOs) controlled highly territorialized aorta T cell responses. ATLOs promoted T cell recruitment, primed CD4+ T cells, generated CD4+, CD8+, T regulatory (Treg) effector and central memory cells, converted naive CD4+ T cells into induced Treg cells, and presented antigen by an unusual set of dendritic cells and B cells. Meanwhile, vascular smooth muscle cell lymphotoxin β receptors (VSMC-LTβRs) protected against atherosclerosis by maintaining structure, cellularity, and size of ATLOs though VSMC-LTβRs did not affect secondary lymphoid organs: Atherosclerosis was markedly exacerbated in Apoe−/−Ltbr−/− and to a similar extent in aged Apoe−/−Ltbrfl/flTagln-cre mice. These data support the conclusion that the immune system employs ATLOs to organize aorta T cell homeostasis during aging and that VSMC-LTβRs participate in atherosclerosis protection via ATLOs

    A novel type of intermittency in a nonlinear dynamo in a compressible flow

    Full text link
    The transition to intermittent mean--field dynamos is studied using numerical simulations of isotropic magnetohydrodynamic turbulence driven by a helical flow. The low-Prandtl number regime is investigated by keeping the kinematic viscosity fixed while the magnetic diffusivity is varied. Just below the critical parameter value for the onset of dynamo action, a transient mean--field with low magnetic energy is observed. After the transition to a sustained dynamo, the system is shown to evolve through different types of intermittency until a large--scale coherent field with small--scale turbulent fluctuations is formed. Prior to this coherent field stage, a new type of intermittency is detected, where the magnetic field randomly alternates between phases of coherent and incoherent large--scale spatial structures. The relevance of these findings to the understanding of the physics of mean--field dynamo and the physical mechanisms behind intermittent behavior observed in stellar magnetic field variability are discussed.Comment: 19 pages, 13 figure

    Real-World Cost-Effectiveness of Pulmonary Vein Isolation for Atrial Fibrillation: A Target Trial Approach

    Get PDF
    OBJECTIVES Randomized controlled trials of pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have proven the procedure's efficacy. Studies assessing its empirical cost-effectiveness outside randomized trial settings are lacking. We aimed to evaluate the effectiveness and cost-effectiveness of PVI versus medical therapy for AF. METHODS We followed a target trial approach using the Swiss-AF cohort, a prospective observational cohort study that enrolled patients with AF between 2014 and 2017. Resource utilization and cost information were collected through claims data. Quality of life was measured with EQ-5D-3L utilities. We estimated incremental cost-effectiveness ratios (ICERs) from the perspective of the Swiss statutory health insurance system. RESULTS Patients undergoing PVI compared with medical therapy had a 5-year overall survival advantage with a hazard ratio of 0.75 (95% CI 0.46-1.21; P = .69) and a 19.8% SD improvement in quality of life (95% CI 15.5-22.9; P < .001), at an incremental cost of 29 604 Swiss francs (CHF) (95% CI 16 354-42 855; P < .001). The estimated ICER was CHF 158 612 per quality-adjusted life-year (QALY) gained within a 5-year time horizon. Assuming similar health effects and costs over 5 additional years changed the ICER to CHF 82 195 per QALY gained. Results were robust to the sensitivity analyses performed. CONCLUSIONS Our results show that PVI might be a cost-effective intervention within the Swiss healthcare context in a 10-year time horizon, but unlikely to be so at 5 years, if a willingness-to-pay threshold of CHF 100 000 per QALY gained is assumed. Given data availability, we find target trial designs are a valuable tool for assessing the cost-effectiveness of healthcare interventions outside of randomized controlled trial settings

    Unilateral spontaneous rupture of a testicular implant thirteen years after bilateral insertion: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>We describe a case of spontaneous, non traumatic rupture of a single artificial testis in a patient who had undergone bilateral, staged radical orchidectomy followed by prosthesis insertion. The consequences and radiological appearances of implant rupture are discussed. We believe it is the longest time interval recorded between prosthesis insertion and rupture.</p> <p>Case presentation</p> <p>A 50 year old Caucasian man presented to our outpatient department with an altered consistency in his right testicular prosthesis without any systemic symptoms or local inflammation. His left testicular prosthesis had retained its consistency since insertion.</p> <p>Conclusion</p> <p>The majority of cases reported to date have required exploration due to symptoms but we describe a case that was managed conservatively.</p

    Omega-3 Fatty Acids and Heart Rhythm, Rate, and Variability in Atrial Fibrillation.

    Get PDF
    Background Previous randomized control trials showed mixed results concerning the effect of omega-3 fatty acids (n-3 FAs) on atrial fibrillation (AF). The associations of n-3 FA blood levels with heart rhythm in patients with established AF are unknown. The goal of this study was to assess the associations of total and individual n-3 FA blood levels with AF type (paroxysmal versus nonparoxysmal), heart rate (HR), and HR variability in patients with AF. Methods and Results Total n-3 FAs, eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid, and alpha-linolenic acid blood levels were determined in 1969 patients with known AF from the SWISS-AF (Swiss Atrial Fibrillation cohort). Individual and total n-3 FAs were correlated with type of AF, HR, and HR variability using standard logistic and linear regression, adjusted for potential confounders. Only a mild association with nonparoxysmal AF was found with total n-3 FA (odds ratio [OR], 0.97 [95% CI, 0.89-1.05]) and docosahexaenoic acid (OR, 0.93 [95% CI, 0.82-1.06]), whereas other individual n-3 FAs showed no association with nonparoxysmal AF. Higher total n-3 FAs (estimate 0.99 [95% CI, 0.98-1.00]) and higher docosahexaenoic acid (0.99 [95% CI, 0.97-1.00]) tended to be associated with slower HR in multivariate analysis. Docosapentaenoic acid was associated with a lower HR variability triangular index (0.94 [95% CI, 0.89-0.99]). Conclusions We found no strong evidence for an association of n-3 FA blood levels with AF type, but higher total n-3 FA levels and docosahexaenoic acid might correlate with lower HR, and docosapentaenoic acid with a lower HR variability triangular index

    Real-world cost-effectiveness of pulmonary vein isolation for atrial fibrillation: a target trial approach.

    Get PDF
    OBJECTIVES Randomized controlled trials of pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have proven the procedure's efficacy. Studies assessing its empirical cost-effectiveness outside randomized trial settings are lacking. We aimed to evaluate the effectiveness and cost-effectiveness of PVI versus medical therapy for AF. METHODS We followed a target trial approach using the Swiss AF cohort, a prospective observational cohort study that enrolled AF patients between 2014 and 2017. Resource utilization and cost information was collected through claims data. Quality-of-life was measured with EQ-5D-3L utilities. We estimated incremental cost-effectiveness ratios from the perspective of the Swiss statutory health insurance system. RESULTS Patients undergoing PVI compared to medical therapy had a 5-year overall survival advantage with a hazard ratio of 0.75 (95%CI 0.46-1.21, p=0.69), a 19.8% standard deviation improvement in quality-of-life (95%CI 15.5-22.9%, p<0.001), at an incremental cost of 29,604 (95%CI 16,354-42,855, p<0.001) Swiss Francs (CHF). The estimated incremental cost-effectiveness ratio was CHF 158,612 per quality-adjusted life-year (QALY) gained within a 5-year time horizon. Assuming similar health effects and costs over 5 additional years changed the incremental cost-effectiveness ratio to CHF 82,195 per QALY gained. Results were robust to the sensitivity analyses performed. CONCLUSIONS Our results show that PVI might be a cost-effective intervention within the Swiss healthcare context in a 10-year time horizon, but unlikely to be so at 5-years, if a willingness-to-pay threshold of CHF100,000 per QALY gained is assumed. Given data availability, we find target trial designs are a valuable tool for assessing the cost-effectiveness of healthcare interventions outside of RCT settings

    Ozone-CO Correlations Determined by the TES Satellite Instrument in Continental Outflow Regions

    Get PDF
    Collocated measurements of tropospheric ozone (O3) and carbon monoxide (CO) from the Tropospheric Emission Spectrometer (TES) aboard the EOS Aura satellite provide information on O3-CO correlations to test our understanding of global anthropogenic influence on O3. We examine the global distribution of TES O3-CO correlations in the middle troposphere (618 hPa) for July 2005 and compare to correlations generated with the GEOS-Chem chemical transport model and with ICARTT aircraft observations over the eastern United States (July 2004). The TES data show significant O3-CO correlations downwind of polluted continents, with dO3/dCO enhancement ratios in the range 0.4–1.0 mol mol−1 and consistent with ICARTT data. The GEOS-Chem model reproduces the O3-CO enhancement ratios observed in continental outflow, but model correlations are stronger and more extensive. We show that the discrepancy can be explained by spectral measurement errors in the TES data. These errors will decrease in future data releases, which should enable TES to provide better information on O3-CO correlations.Earth and Planetary SciencesEngineering and Applied Science
    corecore