Meshless animation of fracturing solids

We present a new meshless animation framework for elastic and plastic materials that fracture. Central to our method is a highly dynamic surface and volume sampling method that supports arbitrary crack initiation, propagation, and termination, while avoiding many of the stability problems of traditional mesh-based techniques. We explicitly model advancing crack fronts and associated fracture surfaces embedded in the simulation volume. When cutting through the material, crack fronts directly affect the coupling between simulation nodes, requiring a dynamic adaptation of the nodal shape functions. We show how local visibility tests and dynamic caching lead to an efficient implementation of these effects based on point collocation. Complex fracture patterns of interacting and branching cracks are handled using a small set of topological operations for splitting, merging, and terminating crack fronts. This allows continuous propagation of cracks with highly detailed fracture surfaces, independent of the spatial resolution of the simulation nodes, and provides effective mechanisms for controlling fracture paths. We demonstrate our method for a wide range of materials, from stiff elastic to highly plastic objects that exhibit brittle and/or ductile fracture. Copyright © 2005 by the Association for Computing Machinery, Inc

Efficient raytracing of deforming point-sampled surfaces

We present efficient data structures and caching schemes to accelerate ray-surface intersections for deforming point-sampled surfaces. By exploiting spatial and temporal coherence of the deformation during the animation, we are able to improve rendering performance by a factor of two to three compared to existing techniques. Starting from a tight bounding sphere hierarchy for the undeformed object, we use a lazy updating scheme to adapt the hierarchy to the deformed surface in each animation step. In addition, we achieve a significant speedup for ray-surface intersections by caching per-ray intersection points. We also present a technique for rendering sharp edges and corners in point-sampled models by introducing a novel surface clipping algorithm. © The Eurographics Association and Blackwell Publishing 2005

Multiresolution particle-based fluids

We propose a new fluid control technique that uses scale-dependent force control to preserve small-scale fluid detail. Control particles define local force fields and can be generated automatically from either a physical simulation or a sequence of target shapes. We use a multi-scale decomposition of the velocity field and apply control forces only to the coarse-scale components of the flow. Small-scale detail is thus preserved in a natural way avoiding the artificial viscosity often introduced by force-based control methods. We demonstrate the effectiveness of our method for both Lagrangian and Eulerian fluid simulation environments

Design of an instrument for measuring the spectral bidirectional scatter distribution function

The spectral bidirectional scatter distribution function (BSDF) offers a complete description of the spectral and spatial optical characteristics of a materia. Any gloss and color measurement can be related to a particular value of the BSDF, while accurate luminaire design with ray tracing software requires the BSDF of reflectors and filters. Many measuring instruments, each having particular advantages and limitations, have been reported in the literature, and an overview of these instruments is included. A measuring instrument that allows for an absolute determination of the spectral BSDF with a full three dimensional spatial coverage in both reflectance and transmittance mode, a broadband spectral coverage, a large dynamic range, a reasonable acquistion time, and a large sample illumination area is presented. The main instrument characteristics are discussed, and the measurement capabilities are illustrated. (C) 2008 Optical Society of Americastatus: publishe

Early Mucosal Healing Predicts Favorable Outcomes in Patients With Moderate to Severe Ulcerative Colitis Treated With Golimumab: Data From the Real-life BE-SMART Cohort

Background: Golimumab (GOL) is registered for moderate to severely active ulcerative colitis (UC). Data on the use of GOL in daily clinical practice are limited. Currently, it is unclear which factors are predictive of a favorable outcome. The goals of this study were to evaluate the mid-term outcome of GOL (week 26) in patients with moderate to severe UC and to determine predictors of favorable outcome. Methods: Patients included in the SMART study (NCT02155335) were evaluated for their mid-term outcome. Demographic data, disease characteristics, and medical history were recorded retrospectively. Data on disease activity based on total Mayo score, previous and concomitant medication, GOL dosing, mucosal healing (Mayo 0 or 1), adverse events (colectomy, hospitalization), and biomarkers (C-reactive protein, fecal calprotectin, hemoglobin, and albumin) were collected at baseline and weeks 2, 6, 14, 26, and 52. GOL was dosed at 200 and 100 mg at weeks 0 and 2, respectively, and 50 mg (<80 kg body weight) or 100 mg (≥80 kg body weight) every 4 weeks thereafter. The primary end point was steroid-free GOL continuation at week 26. Results: From the 91 evaluable patients (42% female; median age, 42 years; median disease duration, 5 years), 4% were active smokers, 25% had extensive colitis, and 38% had an endoscopic Mayo score of 3 at baseline. The median (interquartile range [IQR]) baseline Mayo score was 9 (8-10). Although 75% of patients had previously failed immunomodulators (IMMs), the majority (87%) were anti-tumor necrosis factor (TNF) naïve. GOL was started in combination with IMM in 40% and steroids in 64%. The median (IQR) duration of GOL therapy during follow-up was 35.7 (11.4-105.7) weeks. Twenty-six weeks after GOL induction, 37 patients (41%) were steroid-free and still on GOL, of whom 8 (21.6%) required GOL dose optimization. Short-term mucosal healing (STMH) at week 14 was evaluated in 60% of the patients. Considering the whole cohort, only 40% achieved STMH. No predictors could be retained of short-term treatment outcome. In multivariate analysis, STMH was predictive of steroid-free GOL continuation at week 26 (odds ratio [OR], 5.56; 95% confidence interval [CI], 1.90-16.29; P = 0.002) and week 52 (OR, 9.38; 95% CI, 2.68-32.84; P < 0.001). In patients continuing GOL after week 14, STMH was predictive of intervention-free survival (OR, 2.05; 95% CI, 1.09-3.86; P = 0.026) and discontinuation-free survival (OR, 3.47; 95% CI, 1.58-7.58; P = 0.002). During follow-up, 78% needed an intervention, 68% discontinued GOL, and 3 patients needed a colectomy. Conclusions: Real-life data confirm the moderate effectiveness of GOL on the mid-term in active UC, but therapeutic interventions are frequently needed. Short-term mucosal healing predicts a favorable outcome. 10.1093/ibd/izy219_video1izy219.video15798038438001.status: publishe

Archeologisch booronderzoek Reitdiepwijken 3 te Groningen, gemeente Groningen (GR)

Voor het bureauonderzoek wordt verwezen naar MUG Publicatie 2009-23 (De Roller 2009) dat betrekking heeft op de aangrenzende noordelijke percelen. In de afgelopen twee jaar is de situatie niet zodanig gewijzigd dat er aanvullingen op het bureauonderzoek uit 2009 noodzakelijk zijn. Langs de Friesestraatweg loopt mogelijke een geul met bijbehorende oeverwallen. De oeverwallen zijn aantrekkelijke vestigingsplaatsen voor de mens omdat ze over het algemeen wat droger zijn en hoger liggen dan de omgeving. Uit het booronderzoek blijkt dat binnen het onderzoeksgebied een geul aanwezig is, die vermoedelijk rond de jaartelling zover verland is dat ze geen watervoerende functie meer had. Deels op de geulvulling en op de oeverwallen is een vegetatiehorizont aanwezig dat vermoedelijk uit de 3e eeuw stamt. In twee boringen zijn sporen van fosfaat aangetroffen. Het vegetatiehorizont en de fosfaatsporen zijn aanwijzingen voor menselijke activiteit in het onderzoeksgebied. Mogelijk horen de fosfaatsporen bij de nederzetting net ten oosten van het onderzoeksgebied. Deze nederzetting dateert uit het begin van de jaartelling (Hielkema & De Wit 2007). De terreinomstandigheden (oeverwal en de aanwezigheid van een vegetatiehorizont) binnen het onderzoeksgebied zijn zodanig dat er een goede kans is op menselijke sporen uit de periode ijzertijd-nieuwe tijd. Er wordt daarom aanbevolen vervolgonderzoek uit te voeren in de vorm van een proefsleuvenonderzoek waarbij duidelijk moet worden of er daadwerkelijk bewoningsresten aanwezig zij