Decision making in structural engineering problems under polymorphic uncertainty : a benchmark proposal

The treatment of diverse uncertainties is an important challenge in structural engineering problems, especially from the viewpoint of realistic analysis. Inaccuracy and variability are always present and have to be quantified by either probabilistic, possibilistic, polymorphic or other uncertainty approaches. Regardless to the applied uncertainty quantification method, the numerical predictions have to be useful for structural assessment and decision making. The authors propose in this contribution a benchmark example of a portal frame structure including various uncertainties. The goal of this benchmark study is to compare justifications and decisions provided by different uncertainty models with respect to clear challenges of decision making with and without measurements, data assimilation and design. The engineering problem itself is simple enough to understand and complex enough not to be reduced to a simple formula with uncertain parameters.DFG, 273721697, SPP 1886: Polymorphe Unschärfemodellierungen für den numerischen Entwurf von Strukture

The perfect action for non-degenerate staggered fermions

The perfect action of free staggered fermions is calculated by blocking from the continuum for degenerate and non-degenerate flavor masses. The symmetry structure, connecting flavor transformations and translations, is explained directly from the blocking scheme. It is convenient to use a modified Fourier transformation, respecting this connection, to treat the spin-flavor structure of the blockspins. The perfect action remains local in the non-degenerate case; it is explicitly calculated in two dimensions. I finally comment on the relation of the blocking scheme to the transition from Dirac-K\"ahler fermions to staggered fermions.Comment: 14 pages, Latex2e, 1 Latex figure, some minor changes and two references adde

Results from a real-time dosimetry study during left atrial ablations performed with ultra-low dose radiation settings

Background: Three-dimensional mapping systems and the use of ultra-low dose radiation protocols have supported minimization of radiation dose during left atrial ablation procedures. By using optimal shielding, scattered radiation reaching the operator can be further reduced. This prospective study was designed to determine the remaining operator radiation exposure during left atrial catheter ablations using real-time dosimetry. Methods: Radiation dose was recorded using real-time digital dosimetry badges outside the lead apron during 201 consecutive left atrial fibrillation ablation procedures. All procedures were performed using the same X‑ray system (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Germany) programmed with ultra-low dose radiation settings including a low frame rate (two frames per second), maximum copper filtration, and an optimized detector dose. To reduce scattered radiation to the operators, table-suspended lead curtains, ceiling-suspended leaded plastic shields, and radiation-absorbing shields on the patient were positioned in an overlapping configuration. Results: The 201 procedures included 139 (69%) pulmonary vein isolations (PVI) (20 cryoballoon ablations, 119 radiofrequency ablations, with 35 cases receiving additional ablation of the cavotricuspid isthmus) and 62 (31%) PVI plus further left atrial substrate ablation. Mean radiation dose measured as dose area product for all procedures was 128.09 ± 187.87 cGy ∙ cm2 with a mean fluoroscopy duration of 9.4 ± 8.7 min. Real-time dosimetry showed very low average operator doses of 0.52 ± 0.10 µSv. A subanalysis of 51 (25%) procedures showed that the radiation burden for the operator was highest during pulmonary vein angiography. Conclusion: The use of ultra-low dose radiation protocols in combination with optimized shielding results in extremely low scattered radiation reaching the operator.Hintergrund: Der Einsatz von dreidimensionalen Mapping-Systemen und von Niedrigdosiseinstellungen der Röntgenanlage führte zu einer Minimierung der Strahlenbelastung bei linksatrialen Ablationen. Optimierte Abschirmung kann die Streustrahlung als Strahlenbelastung des Untersuchers weiter reduzieren. In dieser prospektiven Studie wurde untersucht, welcher Strahlenbelastung der Untersucher unter Anwendung dieser Maßnahmen während linksatrialer Ablationen noch ausgesetzt ist. Methoden: Die Strahlenbelastung wurde mittels Echtzeitdosimetrie an der Außenseite der Bleischürze während 201 konsekutiven linksatrialen Ablationen gemessen. Alle Prozeduren wurden mit demselben Röntgensystem (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Deutschland) und mit strahlensparenden Einstellungen durchgeführt, unter anderem mit einer niedrigen Bildrate von 2 Bildern/s, maximaler Kupferfilterung und angepasster Detektoreingangsdosis. Um Streustrahlung zu reduzieren, wurden die Seitenlamellen, die mobile Acrylscheibe und die strahlenabsorbierenden Schilde auf dem Patienten überlappend angeordnet. Ergebnisse: Die 201 Prozeduren umfassten 139 (69%) Pulmonalvenenisolationen (PVI; 20 Kryoballonablationen, 119 Radiofrequenzablationen, in 35 Fällen mit zusätzlicher Ablation des kavotrikuspidalen Isthmus) und 62 (31%) PVI mit zusätzlicher linksatrialer Substratmodifikation. Die Strahlendosis als Dosis-Flächen-Produkt (DAP) betrug durchschnittlich 128,09± 187,87 cGy ⋅cm2 bei einer Fluoroskopiedauer von imMittel 9,4± 8,7min. Die per Echtzeitdosimetrie erhobene mittlere Strahlendosis des Untersuchers zeigte sich mit 0,52± 0,10 μSv als sehr gering. Eine Subanalyse bei 51 (25 %) Prozeduren zeigte, dass die Strahlendosis des Untersuchers während der Pulmonalvenenangiographie am höchsten war. Schlussfolgerung: Die Kombination von Niedrigdosiseinstellungen und optimierter Abschirmung führt zu einer extremniedrigen Streustrahlung als Strahlenbelastung des Untersuchers

Industrial Segment Anything -- a Case Study in Aircraft Manufacturing, Intralogistics, Maintenance, Repair, and Overhaul

Deploying deep learning-based applications in specialized domains like the aircraft production industry typically suffers from the training data availability problem. Only a few datasets represent non-everyday objects, situations, and tasks. Recent advantages in research around Vision Foundation Models (VFM) opened a new area of tasks and models with high generalization capabilities in non-semantic and semantic predictions. As recently demonstrated by the Segment Anything Project, exploiting VFM's zero-shot capabilities is a promising direction in tackling the boundaries spanned by data, context, and sensor variety. Although, investigating its application within specific domains is subject to ongoing research. This paper contributes here by surveying applications of the SAM in aircraft production-specific use cases. We include manufacturing, intralogistics, as well as maintenance, repair, and overhaul processes, also representing a variety of other neighboring industrial domains. Besides presenting the various use cases, we further discuss the injection of domain knowledge

Effects of anisotropy on the geometry of tracer particle trajectories in turbulent flows

Using curvature and torsion to describe Lagrangian trajectories gives a full description of these as well as an insight into small and large time scales as temporal derivatives up to order 3 are involved. One might expect that the statistics of these properties depend on the geometry of the flow. Therefore, we calculated curvature and torsion probability density functions (PDFs) of experimental Lagrangian trajectories processed using the Shake-the-Box algorithm of turbulent von K\'arm\'an flow, Rayleigh-B\'enard convection and a zero-pressure-gradient turbulent boundary layer over a flat plate. The results for the von K\'arm\'an flow compare well with previous experimental results for the curvature PDF and numerical simulation of homogeneous and isotropic turbulence for the torsion PDF. Results for Rayleigh-B\'enard convection agree with those obtained for K\'arm\'an flow, while results for the logarithmic layer within the boundary layer differ slightly, and we provide a potential explanation. To detect and quantify the effect of anisotropy either resulting from a mean flow or large-scale coherent motions on the geometry or tracer particle trajectories, we introduce the curvature vector. We connect its statistics with those of velocity fluctuations and demonstrate that strong large-scale motion in a given spatial direction results in meandering rather than helical trajectories

Oxygen utilization rate (OUR) underestimates ocean respiration: A model study

We use a simple 1-D model representing an isolated density surface in the ocean and 3-D global ocean biogeochemical models to evaluate the concept of computing the subsurface oceanic oxygen utilization rate (OUR) from the changes of apparent oxygen utilization (AOU) and water age. The distribution of AOU in the ocean is not only the imprint of respiration in the ocean's interior but is strongly influenced by transport processes and eventually loss at the ocean surface. Since AOU and water age are subject to advection and diffusive mixing, it is only when they are affected both in the same way that OUR represents the correct rate of oxygen consumption. This is the case only when advection prevails or with uniform respiration rates, when the proportions of AOU and age are not changed by transport. In experiments with the 1-D tube model, OUR underestimates respiration when maximum respiration rates occur near the outcrops of isopycnals and overestimates when maxima occur far from the outcrops. Given the distribution of respiration in the ocean, i.e., elevated rates near high-latitude outcrops of isopycnals and low rates below the oligotrophic gyres, underestimates are the rule. Integrating these effects globally in three coupled ocean biogeochemical and circulation models, we find that AOU-over-age based calculations underestimate true model respiration by a factor of 3. Most of this difference is observed in the upper 1000 m of the ocean with the discrepancies increasing toward the surface where OUR underestimates respiration by as much as factor of 4

Angular momentum and mass evolution of contact binaries

Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each other and contact binaries are formed, following evolutionary paths transform them into systems of two categories: A-type and W-type. The systems evolve in a similar way but under slightly different circumstances. The mass/energy transfer rate is different, leading to quite different evolutionary results. An alternative scenario of evolution in contact is presented and discussed, based on the observational data of over a hundred low-temperature contact binaries. It results from the observed correlations among contact binary physical and orbital parameters. Theoretical tracks are computed assuming angular momentum loss from a system via stellar wind, accompanied by mass transfer from an advanced evolutionary secondary to the main sequence primary. Good agreement is seen between the tracks and the observed graphs. Independently of details of the evolution in contact and a relation between A-type and W-type systems, the ultimate fate of contact binaries involves the coalescence of both components into a single fast rotating star.Comment: 11 pages, 5 figures, a short paragraph added on p. 6, MNRAS, in pres

Upper ocean carbon fluxes in the Atlantic Ocean: The importance of the POC:PIC ratio

The mean depth distribution of the POC:PIC ratio of sinking particles, measured with particle interceptor traps deployed in the Atlantic Ocean, is fitted by an exponential function (POC:PIC = 64.3Z−0.56; r2 = 0.69) The function is successfully evaluated by comparison with (a) estimates of the POC:PIC ratio of export production, computed from seasonal changes of nitrate and alkalinity and (b) estimates of the POC:PIC ratio of remineralization on shallow isopycnals. The basin mean POC:PIC ratio of export production is 4.2–4.37. The POC:PIC-depth function is combined with empirical relationships between the flux of particulate organic matter, primary production and depth, satellite derived primary production data sets, and the regional distribution of ψ (the ratio of released CO2:precipitated carbonate during CaCO3 formation) in order to estimate the effective carbon flux (Jeff) in the Atlantic Ocean. Remineralization of organic carbon above the winter mixed layer (11–17%) and CaCO3 sequestration from the winter mixed layer (13–16%), which is the balance between CaCO3 production and shallow dissolution, are the two main processes which control the difference between export production (0.9 and 2.9 GT C yr−1) and Jeff (0.64 and 2.2 GT C yr−1) on the basin scale (65°N to 65°S). CaCO3 sequestration is the dominant process modulating effective carbon export in the tropics, while shallow POC remineralization dominates in temperate and polar waters. Observed regional patterns like polarward increases of the POC:PIC export ratio and of ψ counteract each other largely when Jeff is computed

Discontinuation of BRAF/MEK-Directed Targeted Therapy after Complete Remission of Metastatic Melanoma—A Retrospective Multicenter ADOReg Study

The advent of BRAF/MEK inhibitors (BRAFi/MEKi) has significantly improved progressionfree (PFS) and overall survival (OS) for patients with advanced BRAF-V600-mutant melanoma. Long-term survivors have been identified particularly among patients with a complete response (CR) to BRAF/MEK-directed targeted therapy (TT). However, it remains unclear which patients who achieved a CR maintain a durable response and whether treatment cessation might be a safe option in these patients. Therefore, this study investigated the impact of treatment cessation on the clinical course of patients with a CR upon BRAF/MEK-directed-TT. We retrospectively selected patients with BRAF-V600-mutant advanced non-resectable melanoma who had been treated with BRAFi ± MEKi therapy and achieved a CR upon treatment out of the multicentric skin cancer registry ADOReg. Data on baseline patient characteristics, duration of TT, treatment cessation, tumor progression (TP) and response to second-line treatments were collected and analyzed. Of 461 patients who received BRAF/MEK-directed TT 37 achieved a CR. TP after initial CR was observed in 22 patients (60%) mainly affecting patients who discontinued TT (n = 22/26), whereas all patients with ongoing TT (n = 11) maintained their CR. Accordingly, patients who discontinued TT had a higher risk of TP compared to patients with ongoing treatment (p < 0.001). However, our data also show that patients who received TT for more than 16 months and who discontinued TT for other reasons than TP or toxicity did not have a shorter PFS compared to patients with ongoing treatment. Response rates to second-line treatment being initiated in 21 patients, varied between 27% for immune-checkpoint inhibitors (ICI) and 60% for BRAFi/MEKi rechallenge. In summary, we identified a considerable number of patients who achieved a CR upon BRAF/MEK-directed TT in this contemporary realworld cohort of patients with BRAF-V600-mutant melanoma. Sustained PFS was not restricted to ongoing TT but was also found in patients who discontinued TT