962 research outputs found

    Generating Humanoid Multi-Contact through Feasibility Visualization

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    We present a feasibility-driven teleoperation framework designed to generate humanoid multi-contact maneuvers for use in unstructured environments. Our framework is designed for motions with arbitrary contact modes and postures. The operator configures a pre-execution preview robot through contact points and kinematic tasks. A fast estimation of the preview robot's quasi-static feasibility is performed by checking contact stability and collisions along an interpolated trajectory. A visualization of Center of Mass (CoM) stability margin, based on friction and actuation constraints, is displayed and can be previewed if the operator chooses to add or remove contacts. Contact points can be placed anywhere on a mesh approximation of the robot surface, enabling motions with knee or forearm contacts. We demonstrate our approach in simulation and hardware on a NASA Valkyrie humanoid, focusing on multi-contact trajectories which are challenging to generate autonomously or through alternative teleoperation approaches

    Authoring and Operating Humanoid Behaviors On the Fly using Coactive Design Principles

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    Humanoid robots have the potential to perform useful tasks in a world built for humans. However, communicating intention and teaming with a humanoid robot is a multi-faceted and complex problem. In this paper, we tackle the problems associated with quickly and interactively authoring new robot behavior that works on real hardware. We bring the powerful concepts of Affordance Templates and Coactive Design methodology to this problem to attempt to solve and explain it. In our approach we use interactive stance and hand pose goals along with other types of actions to author humanoid robot behavior on the fly. We then describe how our operator interface works to author behaviors on the fly and provide interdependence analysis charts for task approach and door opening. We present timings from real robot performances for traversing a push door and doing a pick and place task on our Nadia humanoid robot.Comment: 8 pages, 12 figures, for Humanoids 202

    Current usage of explainer animations in trials: a survey of the UKCRC registered clinical trial units in the UK

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    Background: Explainer animations are a means to communicate aspects of clinical trials to participants in a more engaging and accessible way. Delivered well these have the potential to enhance recruitment and retention. The range of media technology used to deliver this material is expanding rapidly but is highly fragmented. Usage of explainer animations across the UK is unknown, the aim of this research was to determine current usage across the 52 registered UK Clinical Research Collaboration (UKCRC) Clinical Trials Units (CTUs) to understand the current landscape and any barriers that could be preventing wider uptake of this functionality. Methods: A survey link was emailed to all UKCRC CTU Directors and Trial Management Leads to ascertain current usage of explainer animations within their CTU. The survey ran between 01 February 2023 and 07 March 2023. Results: Responses were received from 35 CTUs—representing a response rate of 67%. 24 CTUs (69%) reported that they had created/used at least one explainer animation within their unit, although the usage, cost, length and production activities varied among the units. Conclusions: The survey showed that a high proportion of the UKCRC CTUs have used explainer animations to provide information to participants about clinical studies. For those not using the technology yet, the most common reasons cited were a lack of expertise, lack of resources and costs to produce them. One of the desired outcomes of this project is the creation of a free-to-use library of animations to encourage wider uptake and avoid duplication

    Cortical Plasticity of Audio–Visual Object Representations

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    Several regions in human temporal and frontal cortex are known to integrate visual and auditory object features. The processing of audio–visual (AV) associations in these regions has been found to be modulated by object familiarity. The aim of the present study was to explore training-induced plasticity in human cortical AV integration. We used functional magnetic resonance imaging to analyze the neural correlates of AV integration for unfamiliar artificial object sounds and images in naïve subjects (PRE training) and after a behavioral training session in which subjects acquired associations between some of these sounds and images (POST-training). In the PRE-training session, unfamiliar artificial object sounds and images were mainly integrated in right inferior frontal cortex (IFC). The POST-training results showed extended integration-related IFC activations bilaterally, and a recruitment of additional regions in bilateral superior temporal gyrus/sulcus and intraparietal sulcus. Furthermore, training-induced differential response patterns to mismatching compared with matching (i.e., associated) artificial AV stimuli were most pronounced in left IFC. These effects were accompanied by complementary training-induced congruency effects in right posterior middle temporal gyrus and fusiform gyrus. Together, these findings demonstrate that short-term cross-modal association learning was sufficient to induce plastic changes of both AV integration of object stimuli and mechanisms of AV congruency processing

    Randomised controlled trial of population screening for atrial fibrillation in people aged 70 years and over to reduce stroke: protocol for the SAFER trial

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    Introduction: There is a lack of evidence that the benefits of screening for atrial fibrillation (AF) outweigh the harms. Following the completion of the Screening for Atrial Fibrillation with ECG to Reduce stroke (SAFER) pilot trial, the aim of the main SAFER trial is to establish whether population screening for AF reduces incidence of stroke risk. Methods and analysis: Approximately 82 000 people aged 70 years and over and not on oral anticoagulation are being recruited from general practices in England. Patients on the palliative care register or residents in a nursing home are excluded. Eligible people are identified using electronic patient records from general practices and sent an invitation and consent form to participate by post. Consenting participants are randomised at a ratio of 2:1 (control:intervention) with clustering by household. Those randomised to the intervention arm are sent an information leaflet inviting them to participate in screening, which involves use of a handheld single-lead ECG four times a day for 3 weeks. ECG traces identified by an algorithm as possible AF are reviewed by cardiologists. Participants with AF are seen by a general practitioner for consideration of anticoagulation. The primary outcome is stroke. Major secondary outcomes are: death, major bleeding and cardiovascular events. Follow-up will be via electronic health records for an average of 4 years. The primary analysis will be by intention-to-treat using time-to-event modelling. Results from this trial will be combined with follow-up data from the cluster-randomised pilot trial by fixed-effects meta-analysis. Ethics and dissemination: The London—Central National Health Service Research Ethics Committee (19/LO/1597) provided ethical approval. Dissemination will include public-friendly summaries, reports and engagement with the UK National Screening Committee. Trial registration number: ISRCTN72104369

    Competing Neural Responses for Auditory and Visual Decisions

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    Why is it hard to divide attention between dissimilar activities, such as reading and listening to a conversation? We used functional magnetic resonance imaging (fMRI) to study interference between simple auditory and visual decisions, independently of motor competition. Overlapping activity for auditory and visual tasks performed in isolation was found in lateral prefrontal regions, middle temporal cortex and parietal cortex. When the visual stimulus occurred during the processing of the tone, its activation in prefrontal and middle temporal cortex was suppressed. Additionally, reduced activity was seen in modality-specific visual cortex. These results paralleled impaired awareness of the visual event. Even without competing motor responses, a simple auditory decision interferes with visual processing on different neural levels, including prefrontal cortex, middle temporal cortex and visual regions

    Upward delamination of Cascadia Basin sediment infill with landward frontal accretion thrusting caused by rapid glacial age material flux

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    The Cascadia convergent margin is a first-order research target to study the impact of rapid sedimentation processes on the mechanics of frontal subduction zone accretion. The near-trench part of the accretionary prism offshore Washington is affected by strongly increased glacial age sedimentation and fan formation that led to an outstanding Quaternary growth rate with landward vergent thrust faulting that is rarely observed elsewhere in accretionary wedges. Multichannel seismic reflection data acquired on the ORWELL project allows us to study the structure and dynamics of the atypical frontal accretion processes. We performed a kinematical and mechanical analysis of the frontal accretion structures, and developed a dynamic Coulomb-wedge model for the landward-verging backthrust formation. Backthrusting results from heterogeneous diffuse strain accumulation in the mechanically heterogeneous Cascadia basin sediment succession entering the subduction zone, and strain partitioning along a midlevel detachment that is activated by gravitational loading caused by rapid glacial age sedimentation. These complex deformation processes cause the passive “upward” delamination of the upper turbidite beds from the basal pelagic carbonate section similar to triangle-zone formation and passive backthrust wedging in foreland thrust belts caused by rapid burial beneath syntectonic sediment deposits. The deformation mechanism at the tectonic front of the Cascadia margin is an immediate response to the strongly increased late Pleistocene sediment flux rather than to atypical physical boundary conditions as generally thought

    Perception of Loudness Is Influenced by Emotion

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    Loudness perception is thought to be a modular system that is unaffected by other brain systems. We tested the hypothesis that loudness perception can be influenced by negative affect using a conditioning paradigm, where some auditory stimuli were paired with aversive experiences while others were not. We found that the same auditory stimulus was reported as being louder, more negative and fear-inducing when it was conditioned with an aversive experience, compared to when it was used as a control stimulus. This result provides support for an important role of emotion in auditory perception

    Neuropsychiatric outcomes of stroke

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    The most common neuropsychiatric outcomes of stroke are depression, anxiety, fatigue, and apathy, which each occur in at least 30% of patients and have substantial overlap of prevalence and symptoms. Emotional lability, personality changes, psychosis, and mania are less common but equally distressing symptoms that are also challenging to manage. The cause of these syndromes is not known, and there is no clear relation to location of brain lesion. There are important gaps in knowledge about how to manage these disorders, even for depression, which is the most studied syndrome. Further research is needed to identify causes and interventions to prevent and treat these disorders
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