Auditory enhancement of illusory contour perception

AbstractIllusory contours (ICs) are borders that are perceived in the absence of contrast gradients. Until recently, IC processes were considered exclusively visual in nature and presumed to be unaffected by information from other senses. Electrophysiological data in humans indicates that sounds can enhance IC processes. Despite cross-modal enhancement being observed at the neurophysiological level, to date there is no evidence of direct amplification of behavioural performance in IC processing by sounds. We addressed this knowledge gap. Healthy adults (N=15) discriminated instances when inducers were arranged to form an IC from instances when no IC was formed (NC). Inducers were low-constrast and masked, and there was continuous background acoustic noise throughout a block of trials. On half of the trials, i.e. independently of IC vs. NC, a 1000Hz tone was presented synchronously with the inducer stimuli. Sound presence improved the accuracy of indicating when an IC was presented, but had no impact on performance with NC stimuli (significant IC presence/absence × Sound presence/absence interaction). There was no evidence that this was due to general alerting or to a speed-accuracy trade-off (no main effect of sound presence on accuracy rates and no comparable significant interaction on reaction times). Moreover, sound presence increased sensitivity and reduced bias on the IC vs. NC discrimination task. These results demonstrate that multisensory processes augment mid-level visual functions, exemplified by IC processes. Aside from the impact on neurobiological and computational models of vision our findings may prove clinically beneficial for low-vision or sight-restored patients.

Download Full-text

Auditory Enhancement of Illusory Contour Perception

Multisensory Research ◽

10.1163/22134808-bja10018 ◽

2020 ◽

Vol 34 (1) ◽

pp. 1-15

Author(s):

Ruxandra I. Tivadar ◽

Anna Gaglianese ◽

Micah M. Murray

Keyword(s):

Computational Models ◽

Acoustic Noise ◽

Low Vision ◽

Reaction Times ◽

Contour Perception ◽

Continuous Background ◽

Increased Sensitivity ◽

Direct Amplification ◽

The Impact ◽

Speed Accuracy

Abstract Illusory contours (ICs) are borders that are perceived in the absence of contrast gradients. Until recently, IC processes were considered exclusively visual in nature and presumed to be unaffected by information from other senses. Electrophysiological data in humans indicates that sounds can enhance IC processes. Despite cross-modal enhancement being observed at the neurophysiological level, to date there is no evidence of direct amplification of behavioural performance in IC processing by sounds. We addressed this knowledge gap. Healthy adults () discriminated instances when inducers were arranged to form an IC from instances when no IC was formed (NC). Inducers were low-constrast and masked, and there was continuous background acoustic noise throughout a block of trials. On half of the trials, i.e., independently of IC vs NC, a 1000-Hz tone was presented synchronously with the inducer stimuli. Sound presence improved the accuracy of indicating when an IC was presented, but had no impact on performance with NC stimuli (significant IC presence/absence × Sound presence/absence interaction). There was no evidence that this was due to general alerting or to a speed–accuracy trade-off (no main effect of sound presence on accuracy rates and no comparable significant interaction on reaction times). Moreover, sound presence increased sensitivity and reduced bias on the IC vs NC discrimination task. These results demonstrate that multisensory processes augment mid-level visual functions, exemplified by IC processes. Aside from the impact on neurobiological and computational models of vision, our findings may prove clinically beneficial for low-vision or sight-restored patients.

Download Full-text

Evaluation of the impact of compliance of precast discs of overlapping on the work of the frame of a multi-storey building

E3S Web of Conferences ◽

10.1051/e3sconf/20199704022 ◽

2019 ◽

Vol 97 ◽

pp. 04022

Author(s):

Nikolay Trekin ◽

Emil Kodysh ◽

Alexander Bybka ◽

Alexander Yamalov ◽

Nikita Konkov

Keyword(s):

Economic Performance ◽

Computational Models ◽

Precast Concrete ◽

Building Frames ◽

Frame Building ◽

Numerical Studies ◽

Frame Buildings ◽

The Impact ◽

Structural Solutions ◽

Storey Building

The article provides an analysis and justification of the need to take into account the compliance of discs of overlapping and coatings when calculating frames from precast concrete structures. Previously conducted full-scale experiments showed that the rigidity of the precast overlapping with full filling of the seams, in comparison with the monolithic overlapping, decreases by 3-15 times due to the ductility of the joints. The use of refined computational models of structural solutions for frames, which take into account the compliance of the conjugations of elements, makes it possible to trace possible redistribution of efforts. Such an approach when reconstructing, it is possible to optimally select and calculate the enforcement of structure, and on new designing, to increase reliability and / or improve the economic performance of frame buildings. According to the results of analytical studies, formulas were adopted for the parameters that allow one to take into account the overall compliance of overlapping disks and coatings in computational models of building frames. Numerical studies on the computational model of a frame building made it possible to evaluate the effect of accounting for compliance on the stress-strain state of a multi-storey frame.

Download Full-text

Evaluation of a Coupled Model to Predict the Impact of Adaptive Behaviour in the Thermal Sensation of Occupants of Naturally Ventilated Buildings in Warm-Humid Regions

Sustainability ◽

10.3390/su13010255 ◽

2020 ◽

Vol 13 (1) ◽

pp. 255

Author(s):

Luciano C. de Faria ◽

Marcelo A. Romero ◽

Lúcia F. S. Pirró

Keyword(s):

Computational Models ◽

Thermal Sensation ◽

Coupled Model ◽

Adaptive Behaviour ◽

Humid Climate ◽

Clothing Insulation ◽

Tropical Regions ◽

Naturally Ventilated Buildings ◽

Adaptive Behaviours ◽

The Impact

Improving indoor environment quality and making urban centres in tropical regions more sustainable has become a challenge for which computational models for the prediction of thermal sensation for naturally ventilated buildings (NVBs) have major role to play. This work performed analysis on thermal sensation for non-residential NVBs located in Brazilian tropical warm-humid climate and tested the effectiveness of suggested adaptive behaviours to mitigate warm thermal sensation. The research method utilized transient computational fluid dynamics models coupled with a dynamic model for human thermophysiology to predict thermal sensation. The calculated results were validated with comparison with benchmark values from questionnaires and from field measurements. The calculated results for dynamic thermal sensation (DTS) seven-point scale showed higher agreement with the thermal sensation vote than with the predicted mean vote. The test for the suggested adaptive behaviours considered reducing clothing insulation values from 0.18 to 0.32 clo (reducing DTS from 0.1 to 0.9), increasing the air speed in 0.9 m/s (reducing DTS from 0.1 to 0.9), and applying both suggestions together (reducing DTS from 0.1 to 1.3) for five scenarios with operative temperatures spanning 34.5–24.0 °C. Results quantified the tested adaptive behaviours’ efficiency showing applicability to improve thermal sensation from slightly-warm to neutral.

Download Full-text

Braided composite stent for peripheral vascular applications

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0056 ◽

2020 ◽

Vol 9 (1) ◽

pp. 1137-1146

Author(s):

Qingli Zheng ◽

Pengfei Dong ◽

Zhiqiang Li ◽

Ying Lv ◽

Meiwen An ◽

...

Keyword(s):

Computational Models ◽

Surface Coverage ◽

Mechanical Performance ◽

Wire Diameter ◽

Orthogonal Experimental Design ◽

Braided Composite ◽

Nitinol Wire ◽

Radial Strength ◽

Braiding Angle ◽

The Impact

AbstractBraided composite stent (BCS), woven with nitinol wires and polyethylene terephthalate (PET) strips, provides a hybrid design of stent. The mechanical performance of this novel stent has not been fully investigated yet. In this work, the influence of five main design factors (number of nitinol wires, braiding angle, diameter of nitinol wire, thickness and stiffness of the PET strip) on the surface coverage, radial strength, and flexibility of the BCS were systematically studied using computational models. The orthogonal experimental design was adopted to quantitatively analyze the sensitivity of multiple factors using the minimal number of study cases. Results have shown that the nitinol wire diameter and the braiding angle are two most important factors determining the mechanical performance of the BCS. A larger nitinol wire diameter led to a larger radial strength and less flexibility of the BCS. A larger braiding angle could provide a larger radial strength and better flexibility. In addition, the impact of the braiding angle decreased when the stent underwent a large deformation. At the same time, the impact of the PET strips increased due to the interaction with nitinol wires. Moreover, the number of PET strips played an important role in the surface coverage. This study could help understand the mechanical performance of BCS stent and provides guidance on the optimal design of the stent targeting less complications.

Download Full-text

The Impact of an Improved Flaw Model on a Pressurized Thermal Shock Evaluation

Fatigue, Fracture and Damage Analysis, Volume 2 ◽

10.1115/pvp2002-1360 ◽

2002 ◽

Author(s):

T. L. Dickson ◽

F. A. Simonen

Keyword(s):

Thermal Shock ◽

Computational Models ◽

The United States ◽

Pressure Vessels ◽

Pressurized Water ◽

Evaluation Program ◽

Pressurized Thermal Shock ◽

Computational Methodology ◽

The Impact ◽

Flaw Characterization

The current regulations for pressurized thermal shock (PTS) were derived from computational models that were developed in the early-mid 1980s. The computational models utilized in the 1980s conservatively postulated that all fabrication flaws in reactor pressure vessels (RPVs) were inner-surface breaking flaws. It was recognized at that time that flaw-related data had the greatest level of uncertainty of the inputs required for the probabilistic-based PTS evaluations. To reduce this uncertainty, the United States Nuclear Regulatory Commission (USNRC) has in the past few years supported research at Pacific Northwest National Laboratory (PNNL) to perform extensive nondestructive and destructive examination of actual RPV materials. Such measurements have been used to characterize the number, size, and location of flaws in various types of welds and the base metal used to fabricate RPVs. The USNRC initiated a comprehensive project in 1999 to re-evaluate the current PTS regulations. The objective of the PTS Re-evaluation program has been to incorporate advancements and refinements in relevant technologies (associated with the physics of PTS events) that have been developed since the current regulations were derived. There have been significant improvements in the computational models for thermal hydraulics, probabilistic risk assessment (PRA), human reliability analysis (HRA), materials embrittlement effects on fracture toughness, and fracture mechanics methodology. However, the single largest advancement has been the development of a technical basis for the characterization of fabrication-induced flaws. The USNRC PTS-Revaluation program is ongoing and is expected to be completed in 2002. As part of the PTS Re-evaluation program, the updated risk-informed computational methodology as implemented into the FAVOR (Fracture Analysis of Vessels: Oak Ridge) computer code, including the improved PNNL flaw characterization, was recently applied to a domestic commercial pressurized water reactor (PWR). The objective of this paper is to apply the same updated computational methodology to the same PWR, except utilizing the 1980s flaw model, to isolate the impact of the improved PNNL flaw characterization on the PTS analysis results. For this particular PWR, the improved PNNL flaw characterization significantly reduced the frequency of RPV failure, i.e., by between one and two orders of magnitude.

Download Full-text

Stereoscopically Observed Deformations of a Compliant Abdominal Aortic Aneurysm Model

Journal of Biomechanical Engineering ◽

10.1115/1.4005416 ◽

2011 ◽

Vol 133 (11) ◽

Cited By ~ 12

Author(s):

Clark A. Meyer ◽

Eric Bertrand ◽

Olivier Boiron ◽

Valérie Deplano

Keyword(s):

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Computational Models ◽

Imaging System ◽

Strain Differences ◽

Cyclic Strain ◽

Experimental Models ◽

Body Motion ◽

Abdominal Aortic ◽

The Impact

A new experimental setup has been implemented to precisely measure the deformations of an entire model abdominal aortic aneurysm (AAA). This setup addresses a gap between the computational and experimental models of AAA that have aimed at improving the limited understanding of aneurysm development and rupture. The experimental validation of the deformations from computational approaches has been limited by a lack of consideration of the large and varied deformations that AAAs undergo in response to physiologic flow and pressure. To address the issue of experimentally validating these calculated deformations, a stereoscopic imaging system utilizing two cameras was constructed to measure model aneurysm displacement in response to pressurization. The three model shapes, consisting of a healthy aorta, an AAA with bifurcation, and an AAA without bifurcation, were also evaluated with computational solid mechanical modeling using finite elements to assess the impact of differences between material properties and for comparison against the experimental inflations. The device demonstrated adequate accuracy (surface points were located to within 0.07 mm) for capturing local variation while allowing the full length of the aneurysm sac to be observed at once. The experimental model AAA demonstrated realistic aneurysm behavior by having cyclic strains consistent with reported clinical observations between pressures 80 and 120 mm Hg. These strains are 1–2%, and the local spatial variations in experimental strain were less than predicted by the computational models. The three different models demonstrated that the asymmetric bifurcation creates displacement differences but not cyclic strain differences within the aneurysm sac. The technique and device captured regional variations of strain that are unobservable with diameter measures alone. It also allowed the calculation of local strain and removed rigid body motion effects on the strain calculation. The results of the computations show that an asymmetric aortic bifurcation created displacement differences but not cyclic strain differences within the aneurysm sac.

Download Full-text

Development of Model for Acoustic Noise Generated from Bedload in Rivers

10.5194/egusphere-egu21-9822 ◽

2021 ◽

Author(s):

Mohamad Nasr ◽

Thomas Geay ◽

Sébastien Zanker ◽

Recking Alain

Keyword(s):

Grain Size ◽

Size Distribution ◽

Impact Velocity ◽

Acoustic Noise ◽

Acoustic Power ◽

Bedload Transport ◽

Empirical Formulas ◽

Impact Rate ◽

Flux Measurements ◽

The Impact

Quantifying bedload transport is important for many applications such as river management and hydraulic structures protection. Bedload flux measurements can be achieved using physical sampler methods. However, these methods are expensive, time-consuming, and difficult to operate during high discharge events. Besides, these methods do not permit to capture the spatial and temporal variability of bedload transport flux. Recently, alternative measuring technologies have been developed to continuously monitor bedload flux and grain size distribution using passive or active sensors. Among them, the hydrophone was used to monitor bedload transport by recording the sounds generated by bedload particles colliding on the river bed (referred as self-generated noise SGN). The acoustic power of SGN was correlated with bedload flux in field experiments. To better understand these experimental results and to estimate measurement uncertainties, we developed a theoretical model to simulate the SGN. The model computes an estimation of the power spectral density (PSD)by considering the contribution of all signals generated by impacts between bedload particles and the riverbed, and accounting for the attenuation of the acoustic signal between the source and the hydrophone position due to river propagation effects,. In this model, weThe energy of acoustic noise generated from the collision between two particles is mainly dependent on the transported particles' diameter and the impact velocity. We tested different empirical formulas for the estimation of the number of impact (impact rate) and the impact velocity depending on particle size and hydraulic conditions. To characterize the acoustic power losses as a function of distance and frequency, we used an attenuation function which was experimentally calibrated for different French rivers.We tested the model on a field dataset comprising acoustic and bedload flux measurements. The results indicate that the PSD model allows estimating acoustic power (in between a range of one order of magnitude) for most of the rivers considered.&#160; The model sensitivity was evaluated. In particular, we observed that it is very sensitive to the empirical formulas used to determine the impact rate and impact speed. In addition, special attention should be kept in mind on the assumption of the grain size distribution of riverbed which can generate large variability in some rivers particularly in rivers with a significant sand fraction.

Download Full-text

Quantifying lower tropospheric methane concentrations using GOSAT near-IR and TES thermal IR measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-8-3433-2015 ◽

2015 ◽

Vol 8 (8) ◽

pp. 3433-3445 ◽

Cited By ~ 13

Author(s):

J. R. Worden ◽

A. J. Turner ◽

A. Bloom ◽

S. S. Kulawik ◽

J. Liu ◽

...

Keyword(s):

Near Infrared ◽

Surface Fluxes ◽

Vertical Profiles ◽

Monthly Average ◽

Near Ir ◽

Surface Measurements ◽

Increased Sensitivity ◽

The Impact ◽

Total Column ◽

Methane Concentrations

Abstract. Evaluating surface fluxes of CH4 using total column data requires models to accurately account for the transport and chemistry of methane in the free troposphere and stratosphere, thus reducing sensitivity to the underlying fluxes. Vertical profiles of methane have increased sensitivity to surface fluxes because lower tropospheric methane is more sensitive to surface fluxes than a total column, and quantifying free-tropospheric CH4 concentrations helps to evaluate the impact of transport and chemistry uncertainties on estimated surface fluxes. Here we demonstrate the potential for estimating lower tropospheric CH4 concentrations through the combination of free-tropospheric methane measurements from the Aura Tropospheric Emission Spectrometer (TES) and XCH4 (dry-mole air fraction of methane) from the Greenhouse gases Observing SATellite – Thermal And Near-infrared for carbon Observation (GOSAT TANSO, herein GOSAT for brevity). The calculated precision of these estimates ranges from 10 to 30 ppb for a monthly average on a 4° × 5° latitude/longitude grid making these data suitable for evaluating lower-tropospheric methane concentrations. Smoothing error is approximately 10 ppb or less. Comparisons between these data and the GEOS-Chem model demonstrate that these lower-tropospheric CH4 estimates can resolve enhanced concentrations over flux regions that are challenging to resolve with total column measurements. We also use the GEOS-Chem model and surface measurements in background regions across a range of latitudes to determine that these lower-tropospheric estimates are biased low by approximately 65 ppb, with an accuracy of approximately 6 ppb (after removal of the bias) and an actual precision of approximately 30 ppb. This 6 ppb accuracy is consistent with the accuracy of TES and GOSAT methane retrievals.

Download Full-text

Approach and avoidance learning in patients with major depression and healthy controls: relation to anhedonia

Psychological Medicine ◽

10.1017/s0033291709990468 ◽

2009 ◽

Vol 40 (3) ◽

pp. 433-440 ◽

Cited By ~ 81

Author(s):

H. W. Chase ◽

M. J. Frank ◽

A. Michael ◽

E. T. Bullmore ◽

B. J. Sahakian ◽

...

Keyword(s):

Positive Reinforcement ◽

Negative Reinforcement ◽

Local Population ◽

Reaction Times ◽

Negative Bias ◽

Healthy Controls ◽

Approach And Avoidance ◽

Depressed Patients ◽

Increased Sensitivity ◽

Global Reduction

BackgroundCentral to understanding of the behavioural consequences of depression has been the theory that the disorder is accompanied by an increased sensitivity to negative compared with positive reinforcement (negative bias), whereas other theorists have emphasized a global reduction in sensitivity to reinforcement in depression (blunting).MethodIn this study, we used a probabilistic selection task that was designed to examine independently rates of learning to predict both positive and negative reinforcement. Twenty-three depressed out-patients and 23 healthy controls from the local population participated in the study.ResultsNo evidence for a negative bias was observed on the task, either during acquisition of the task or during generalization of the learned information. Depressed patients responded slower on the task than controls but showed a similar modulation of reaction times (RTs) as controls following reinforcement. Evidence for blunting was observed on the training phase, as reflected in reduced trial-by-trial adjustment during this phase. However, this effect was related specifically to the severity of anhedonia, as measured by the Snaith–Hamilton Pleasure Scale (SHAPS), and was independent of overall depression severity.ConclusionsWe argue that the observation of a negative bias or blunting in a group of depressed patients may be dependent on the neuropsychological task and the symptoms of the patients tested. Our results provide insight into how these theories might be further tested.

Download Full-text

A Diffusion Model Approach for Understanding the Impact of 17 Interventions on the Race Implicit Association Test

10.31124/advance.13270910.v1 ◽

2020 ◽

Author(s):

Jessica Röhner ◽

Calvin K. Lai

Keyword(s):

Decision Making ◽

Implicit Association Test ◽

Association Test ◽

Implicit Measure ◽

Implicit Association ◽

Implicit Measures ◽

Long Term Effects ◽

Sham Intervention ◽

The Impact ◽

Speed Accuracy

Performance on implicit measures reflects construct-specific and non-construct-specific processes. This creates an interpretive issue for understanding interventions to change implicit measures: change in performance could reflect changes in the constructs-of-interest or changes in other mental processes. We re-analyzed data from six studies (N = 23,342) to examine the process-level effects of 17 interventions and one sham intervention to change race Implicit Association Test (IAT) performance. Diffusion models decompose overall IAT performance (D-scores) into construct-specific (ease of decision-making), and non-construct-specific processes (speed-accuracy tradeoffs, non-decision-related processes like motor execution). Interventions that effectively reduced D-scores changed ease of decision-making on compatible and incompatible trials. They also eliminated differences in speed-accuracy tradeoffs between compatible and incompatible trials. Non-decision-related processes were impacted by two interventions only. There was little evidence that interventions had any long-term effects. These findings highlight the value of diffusion modeling for understanding the mechanisms by which interventions affect implicit measure performance.

Download Full-text