Numerical simulation round robin of a coupled volume case: Preliminary results

International audienceThe advantages and limitations of most numerical methods in room acoustics have to date been primarily evaluated in single-volume room conditions, placing emphasis on early reflection components and the early part of the room acoustic impulse response. Few studies have examined the capabilities of simulations to model correctly the case of coupled volumes, where the late part of the impulse response is not a simple extension of the early part and needs to be accurately represented. This work presents preliminary results of a round robin study comparing numerical simulation results with coupled volume theory, using physical scale model measurements to define general parameters. Numerical methods included geometrical acoustic solutions, with image source method and ray/cone/path-tracing type approaches, and wave-based methods, comprising several FDTD implementations. A scale model was used to set the parameters of a statistical model to ensure a physically realistic configuration. Room model coordinates were specified. To avoid issues regarding variations in implementation of material and scattering behaviors across methods, the reverberation time of separate individual volumes was prescribed in the uncoupled condition. Volumes were then coupled and the results analyzed. The comparison is of a rather simplified room acoustic model, assuming homogeneous boundary conditions

Constitutively active acetylcholine-dependent potassium current increases atrial defibrillation threshold by favoring post-shock re-initiation

Electrical cardioversion (ECV), a mainstay in atrial fibrillation (AF) treatment, is unsuccessful in up to 10-20% of patients. An important aspect of the remodeling process caused by AF is the constitutive activition of the atrium-specific acetylcholine-dependent potassium current (I-K,I-ACh -> I-K,I-ACh-c), which is associated with ECV failure. This study investigated the role of I-K,I-ACh-c in ECV failure and setting the atrial defibrillation threshold (aDFT) in optically mapped neonatal rat cardiomyocyte monolayers. AF was induced by burst pacing followed by application of biphasic shocks of 25-100 V to determine aDFT. Blocking I-K,I-ACh-c by tertiapin significantly decreased DFT, which correlated with a significant increase in wavelength during reentry. Genetic knockdown experiments, using lentiviral vectors encoding a Kcnj5-specific shRNA to modulate I-K,I-ACh-c, yielded similar results. Mechanistically, failed ECV was attributed to incomplete phase singularity (PS) removal or reemergence of PSs (i.e. re-initiation) through unidirectional propagation of shock-induced action potentials. Re-initiation occurred at significantly higher voltages than incomplete PS-removal and was inhibited by I-K,I-ACh-c blockade. Whole-heart mapping confirmed our findings showing a 60% increase in ECV success rate after I-K,I-ACh-c blockade. This study provides new mechanistic insight into failing ECV of AF and identifies I-K,I-ACh-c as possible atrium-specific target to increase ECV effectiveness, while decreasing its harmfulness

Development of an antibody fragment that stabilizes GPCR/G-protein complexes.

Single-particle cryo-electron microscopy (cryo-EM) has recently enabled high-resolution structure determination of numerous biological macromolecular complexes. Despite this progress, the application of high-resolution cryo-EM to G protein coupled receptors (GPCRs) in complex with heterotrimeric G proteins remains challenging, owning to both the relative small size and the limited stability of these assemblies. Here we describe the development of antibody fragments that bind and stabilize GPCR-G protein complexes for the application of high-resolution cryo-EM. One antibody in particular, mAb16, stabilizes GPCR/G-protein complexes by recognizing an interface between Gα and Gβγ subunits in the heterotrimer, and confers resistance to GTPγS-triggered dissociation. The unique recognition mode of this antibody makes it possible to transfer its binding and stabilizing effect to other G-protein subtypes through minimal protein engineering. This antibody fragment is thus a broadly applicable tool for structural studies of GPCR/G-protein complexes

SIM-PIPE DryRunner: An approach for testing container-based big data pipelines and generating simulation data

Big data pipelines are becoming increasingly vital in a wide range of data intensive application domains such as digital healthcare, telecommunication, and manufacturing for efficiently processing data. Data pipelines in such domains are complex and dynamic and involve a number of data processing steps that are deployed on heterogeneous computing resources under the realm of the Edge-Cloud paradigm. The processes of testing and simulating big data pipelines on heterogeneous resources need to be able to accurately represent this complexity. However, since big data processing is heavily resource-intensive, it makes testing and simulation based on historical execution data impractical. In this paper, we introduce the SIM - PIPE Dry Runner approach - a dry run approach that deploys a big data pipeline step by step in an isolated environment and executes it with sample data; this approach could be used for testing big data pipelines and realising practical simulations using existing simulators.acceptedVersio

Patients’ vs. Physicians’ Assessments of Emergencies: The Prudent Layperson Standard

Objective: To compare perception of the need for emergency care by emergency department (ED) patients vs. emergency physicians (EPs). Methods: Mailed survey to EPs and a convenience sample of ED patients. Survey rated urgency of acute sore throat, ankle injury, abdominal pain, and hemiparesis, as well as the best definition of “emergency.” Responses were compared with chi-square (p < .05). Results: 119/140 (85%) of EPs and 1453 ED patients responded. EPs were more likely to judge acute abdominal pain (79.8% vs. 43.4%, p < 0.001, odds ratio (OR) 5.16, 95% confidence interval (CI) 3.19-8.40) and hemiparesis (100% vs. 82.6%, p < 0.001, OR 24.9, 95% CI 3.75-94.4) as an emergency. Similar proportions of ED patients and EPs considered sore throat (12.2% vs. 7.6%, p = 0.18, OR 0.59, CI 0.27-1.23) and ankle injury (46.9% vs. 38.6%, p = 0.10, OR 0.71, CI 0.48-1.06) an emergency. EPs (35%) and ED patients (40%) agreed to a similar degree with the “prudent layperson” definition, “a condition that may result in death, permanent disability, or severe pain.” (p = .36, OR 1.22, CI 0.81-1.84). EPs were more likely to add, “the condition prevented work,” (27% vs. 16%, p = 0.003, OR 0.51, CI 0.33-0.81). Patients more often added, “occurred outside business hours” (15% vs. 4%, p = 0.002, OR 4.0, CI = 1.5-11.3). Conclusion: For serious complaints, ED patients’ thresholds for seeking care are higher than judged appropriate by EPs. Stroke is not uniformly recognized as an emergency. Absent consensus for the “correct” threshold, the prudent layperson standard is appropriate

Editorial: Maritime and port economic geography

Unlike the flows of capital and information, international trade involves exchanges of material goods and is largely dependent upon the organisation and capacity of one mode of transport: shipping. The growth in trade in manufactured goods and components has been made possible by containerisation, a sector of the maritime transport industry whose efficiency is at the logistical heart of globalisation. An industry in transition Since the 1970s, flows of manufactured goods have been the princip..

Three Poems from The Elder Project, Vernon School District 22

Poetry by Vernon School District secondary students and their elders, in collaboration with The Elder Project organized by Wendy Morton and Sandra Lynxleg