382 research outputs found
Vortex formation and instability in the left ventricle
We study the formation of the mitral vortex ring during early diastolic
filling in a patient-specific left ventricle (LV) using direct numerical
simulation. The geometry of the left ventricle is reconstructed from Magnetic
Resonance Imaging (MRI) data of a healthy human subject. The left ventricular
kinematics is modeled via a cell-based activation methodology, which is
inspired by cardiac electro-physiology and yields physiologic LV wall motion.
In the fluid dynamics videos, we describe in detail the three-dimensional
structure of the mitral vortex ring, which is formed during early diastolic
filling. The ring starts to deform as it propagates toward the apex of the
heart and becomes inclined. The trailing secondary vortex tubes are formed as
the result of interaction between the vortex ring and the LV wall. These vortex
tubes wrap around the circumference and begin to interact with and destabilize
the mitral vortex ring. At the end of diastole, the vortex ring impinges on the
LV wall and the large-scale intraventricular flow rotates in clockwise
direction. We show for the first time that the mitral vortex ring evolution is
dominated by a number of vortex-vortex and vortex-wall interactions, including
lateral straining and deformation of vortex ring, the interaction of two vortex
tubes with unequal strengths, helicity polarization of vortex tubes and
twisting instabilities of the vortex cores
Interactive Visualization Lab
ABSTRACT This presentation describes the philosophy and ongoing interdisciplinary research projects of the Interactive Visualization Lab at the University of Minnesota
Poster: Getting All Your Bats in a Row: Optimizing Layout in Chronophotographic Style Visualizations
Pain Coping Skills Training for Patients Who Catastrophize About Pain Prior to Knee Arthroplasty: A Multisite Randomized Clinical Trial
BACKGROUND:
Pain catastrophizing has been identified as a prognostic indicator of poor outcome following knee arthroplasty. Interventions to address pain catastrophizing, to our knowledge, have not been tested in patients undergoing knee arthroplasty. The purpose of this study was to determine whether pain coping skills training in persons with moderate to high pain catastrophizing undergoing knee arthroplasty improves outcomes 12 months postoperatively compared with usual care or arthritis education.
METHODS:
A multicenter, 3-arm, single-blinded, randomized comparative effectiveness trial was performed involving 5 university-based medical centers in the United States. There were 402 randomized participants. The primary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain Scale, measured at baseline, 2 months, 6 months, and 12 months following the surgical procedure.
RESULTS:
Participants were recruited from January 2013 to June 2016. In 402 participants, 66% were women and the mean age of the participants (and standard deviation) was 63.2 ± 8.0 years. Three hundred and forty-six participants (90% of those who underwent a surgical procedure) completed a 12-month follow-up. All 3 treatment groups had large improvements in 12-month WOMAC pain scores with no significant differences (p > 0.05) among the 3 treatment arms. No differences were found between WOMAC pain scores at 12 months for the pain coping skills and arthritis education groups (adjusted mean difference, 0.3 [95% confidence interval (CI), -0.9 to 1.5]) or between the pain coping and usual-care groups (adjusted mean difference, 0.4 [95% CI, -0.7 to 1.5]). Secondary outcomes also showed no significant differences (p > 0.05) among the 3 groups.
CONCLUSIONS:
Among adults with pain catastrophizing undergoing knee arthroplasty, cognitive behaviorally based pain coping skills training did not confer pain or functional benefit beyond the large improvements achieved with usual surgical and postoperative care. Future research should develop interventions for the approximately 20% of patients undergoing knee arthroplasty who experience persistent function-limiting pain.
LEVEL OF EVIDENCE:
Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence
Artifact-Based Rendering: Harnessing Natural and Traditional Visual Media for More Expressive and Engaging 3D Visualizations
We introduce Artifact-Based Rendering (ABR), a framework of tools,
algorithms, and processes that makes it possible to produce real, data-driven
3D scientific visualizations with a visual language derived entirely from
colors, lines, textures, and forms created using traditional physical media or
found in nature. A theory and process for ABR is presented to address three
current needs: (i) designing better visualizations by making it possible for
non-programmers to rapidly design and critique many alternative data-to-visual
mappings; (ii) expanding the visual vocabulary used in scientific
visualizations to depict increasingly complex multivariate data; (iii) bringing
a more engaging, natural, and human-relatable handcrafted aesthetic to data
visualization. New tools and algorithms to support ABR include front-end
applets for constructing artifact-based colormaps, optimizing 3D scanned meshes
for use in data visualization, and synthesizing textures from artifacts. These
are complemented by an interactive rendering engine with custom algorithms and
interfaces that demonstrate multiple new visual styles for depicting point,
line, surface, and volume data. A within-the-research-team design study
provides early evidence of the shift in visualization design processes that ABR
is believed to enable when compared to traditional scientific visualization
systems. Qualitative user feedback on applications to climate science and brain
imaging support the utility of ABR for scientific discovery and public
communication.Comment: Published in IEEE VIS 2019, 9 pages of content with 2 pages of
references, 12 figure
The State of the Art of Spatial Interfaces for 3D Visualization
International audienceWe survey the state of the art of spatial interfaces for 3D visualization. Interaction techniques are crucial to data visualization processes and the visualization research community has been calling for more research on interaction for years. Yet, research papers focusing on interaction techniques, in particular for 3D visualization purposes, are not always published in visualization venues, sometimes making it challenging to synthesize the latest interaction and visualization results. We therefore introduce a taxonomy of interaction technique for 3D visualization. The taxonomy is organized along two axes: the primary source of input on the one hand and the visualization task they support on the other hand. Surveying the state of the art allows us to highlight specific challenges and missed opportunities for research in 3D visualization. In particular, we call for additional research in: (1) controlling 3D visualization widgets to help scientists better understand their data, (2) 3D interaction techniques for dissemination, which are under-explored yet show great promise for helping museum and science centers in their mission to share recent knowledge, and (3) developing new measures that move beyond traditional time and errors metrics for evaluating visualizations that include spatial interaction
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