72 research outputs found

    Metabolic Power Method: Underestimation of Energy Expenditure in Field-Sport Movements Using a Global Positioning System Tracking System

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    The purpose of this study was to assess the validity of a global positioning system (GPS) tracking system to estimate energy expenditure (EE) during exercise and field-sport locomotor movements. Twenty-seven participants each completed a 90-min exercise session on an outdoor synthetic futsal pitch. During the exercise session, they wore a 5-Hz GPS unit interpolated to 15 Hz and a portable gas analyzer that acted as the criterion measure of EE. The exercise session was composed of alternating 5-minute exercise bouts of randomized walking, jogging, running, or a field-sport circuit (×3) followed by 10 min of recovery. One-way analysis of variance showed significant (P &lt; .01) and very large underestimations between GPS metabolic power– derived EE and oxygen-consumption (VO2) -derived EE for all field-sport circuits (% difference ≈ –44%). No differences in EE were observed for the jog (7.8%) and run (4.8%), whereas very large overestimations were found for the walk (43.0%). The GPS metabolic power EE over the entire 90-min session was significantly lower (P &lt; .01) than the VO2 EE, resulting in a moderate underestimation overall (–19%). The results of this study suggest that a GPS tracking system using the metabolic power model of EE does not accurately estimate EE in field-sport movements or over an exercise session consisting of mixed locomotor activities interspersed with recovery periods; however, is it able to provide a reasonably accurate estimation of EE during continuous jogging and running.</jats:p

    Quantum dot-labelled polymer beads by suspension polymerisation

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    CdSe quantum dots with polymerisable ligands have been incorporated into polystyrene beads, via a suspension polymerisation reaction, as a first step towards the optical encoding of solid supports for application in solid phase organic chemistry

    Voice Conversion with Conditional SampleRNN

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    Here we present a novel approach to conditioning the SampleRNN generative model for voice conversion (VC). Conventional methods for VC modify the perceived speaker identity by converting between source and target acoustic features. Our approach focuses on preserving voice content and depends on the generative network to learn voice style. We first train a multi-speaker SampleRNN model conditioned on linguistic features, pitch contour, and speaker identity using a multi-speaker speech corpus. Voice-converted speech is generated using linguistic features and pitch contour extracted from the source speaker, and the target speaker identity. We demonstrate that our system is capable of many-to-many voice conversion without requiring parallel data, enabling broad applications. Subjective evaluation demonstrates that our approach outperforms conventional VC methods.Comment: Accepted at Interspeech 2018, Hyderabad, India. This version matches the final version submitted to the conferenc

    An empirical study of Conv-TasNet

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    Conv-TasNet is a recently proposed waveform-based deep neural network that achieves state-of-the-art performance in speech source separation. Its architecture consists of a learnable encoder/decoder and a separator that operates on top of this learned space. Various improvements have been proposed to Conv-TasNet. However, they mostly focus on the separator, leaving its encoder/decoder as a (shallow) linear operator. In this paper, we conduct an empirical study of Conv-TasNet and propose an enhancement to the encoder/decoder that is based on a (deep) non-linear variant of it. In addition, we experiment with the larger and more diverse LibriTTS dataset and investigate the generalization capabilities of the studied models when trained on a much larger dataset. We propose cross-dataset evaluation that includes assessing separations from the WSJ0-2mix, LibriTTS and VCTK databases. Our results show that enhancements to the encoder/decoder can improve average SI-SNR performance by more than 1 dB. Furthermore, we offer insights into the generalization capabilities of Conv-TasNet and the potential value of improvements to the encoder/decoder.Comment: In proceedings of ICASSP202

    Long Term Performance Retention Test Using High Power COTS NiCd and NiMH Cells

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    Contents include the following: Introduction to space-flight high power applications. Problem description for current designs. Test plan for NiCd and NiMn. Results and analysis. Conclusion

    Keep Your Chin Up, and Keep Eating : Perceptions of Barriers and Facilitators to Healthful Dietary Behaviors Among Individuals With Gastrointestinal Cancer and Caregivers

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    BACKGROUND: This study explored perceptions of barriers and facilitators to healthful dietary behaviors among patients with gastrointestinal (GI) cancer and their caregivers, including caregiver preparedness, patient and caregiver self-efficacy for symptom management, and other environmental, social, and familial factors that may serve as barriers and facilitators to healthful eating. METHODS: Using a concurrent mixed methods cross-sectional study design, individuals with GI cancer receiving outpatient chemotherapy and their caregivers completed surveys, dietary assessments, and interviews. Caregiving preparedness, self-efficacy for symptom management, and dietary intake were assessed using validated instruments. Dietary quality was measured using the Healthy Eating Index (HEI)-2020. In-depth interviews explored barriers and facilitators to healthful eating, symptom management, and caregiver preparedness. RESULTS: Twenty-seven patient-caregiver dyads completed study activities (N = 54). Dietary quality scores ranged from 26 to 81, with a median score of 43 for patients and 42 for caregivers. Thematic analysis identified three barriers to healthful eating: caregiver self-efficacy and preparedness, caregiver needs are neglected, and nutrition as a source of conflict. Overall self-efficacy scores (Mdn, [IQR]) were 69.1 (45.0) for caregivers and 75.6 (34.1) for patients. Caregiver preparedness score was 2.99 ± .87; problem areas were identified, including addressing emotional needs, fluctuating eating habits, advanced disease progression and making care activities pleasant. Despite the challenges, three main facilitators were identified: increased awareness and value of nutrition, influential others, and positive coping. CONCLUSION: Our findings suggest the importance of developing interventions that increase nutrition-related preparedness among caregivers and self-efficacy for managing treatment side effects. Future research should continue to explore the relationship between positive coping and dietary behaviors. While engaging patients and caregivers together during dietary interventions is a promising modality, strategies for maintaining personal nutrition-related goals when facing contrasting priorities between patients and caregivers should be addressed

    20V, 40 Ah Lithium Ion Polymer Battery for the Spacesuit

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    Objective: Consider a new battery design for EMU. Results: a) Electrovaya s aerospace cell production line is improving, but must further improve to achieve acceptable reliability; b) Completed functional, vibration, and thermal cycling of LIB; c) So far, electrical safety tests have produced good results; d) Completed functional, vibration, thermal cycling, power quality and EMI of LIB Charger; e) Completed CDR on 9/23/04; and f) Manufacturing Readiness Review for flight cell/battery production scheduled for Dec 04

    Thermal Runaway of Li-Ion Cells: How Internal Dynamics, Mass Ejection, and Heat Vary with Cell Geometry and Abuse Type

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    Thermal runaway of lithium-ion batteries can involve various types of failure mechanisms each with their own unique characteristics. Using fractional thermal runaway calorimetry and high-speed radiography, the response of three different geometries of cylindrical cell (18650, 21700, and D-cell) to different abuse mechanisms (thermal, internal short circuiting, and nail penetration) are quantified and statistically examined. Correlations between the geometry of cells and their thermal behavior are identified, such as increasing heat output per amp-hour (kJ Ah-1) of cells with increasing cell diameter during nail penetration. High-speed radiography reveals that the rate of thermal runaway propagation within cells is generally highest for nail penetration where there is a relative increase in rate of propagation with increasing diameter, compared to thermal or internal short-circuiting abuse. For a given cell model tested under the same conditions, a distribution of heat output is observed with a trend of increasing heat output with increased mass ejection. Finally, internal temperature measurements using thermocouples embedded in the penetrating nail are shown to be unreliable thus demonstrating the need for care when using thermocouples where the temperature is rapidly changing. All data used in this manuscript are open access through the NREL and NASA Battery Failure Databank

    Integrating the OHIF Viewer into XNAT: Achievements, Challenges and Prospects for Quantitative Imaging Studies.

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    Purpose: XNAT is an informatics software platform to support imaging research, particularly in the context of large, multicentre studies of the type that are essential to validate quantitative imaging biomarkers. XNAT provides import, archiving, processing and secure distribution facilities for image and related study data. Until recently, however, modern data visualisation and annotation tools were lacking on the XNAT platform. We describe the background to, and implementation of, an integration of the Open Health Imaging Foundation (OHIF) Viewer into the XNAT environment. We explain the challenges overcome and discuss future prospects for quantitative imaging studies. Materials and methods: The OHIF Viewer adopts an approach based on the DICOM web protocol. To allow operation in an XNAT environment, a data-routing methodology was developed to overcome the mismatch between the DICOM and XNAT information models and a custom viewer panel created to allow navigation within the viewer between different XNAT projects, subjects and imaging sessions. Modifications to the development environment were made to allow developers to test new code more easily against a live XNAT instance. Major new developments focused on the creation and storage of regions-of-interest (ROIs) and included: ROI creation and editing tools for both contour- and mask-based regions; a "smart CT" paintbrush tool; the integration of NVIDIA's Artificial Intelligence Assisted Annotation (AIAA); the ability to view surface meshes, fractional segmentation maps and image overlays; and a rapid image reader tool aimed at radiologists. We have incorporated the OHIF microscopy extension and, in parallel, introduced support for microscopy session types within XNAT for the first time. Results: Integration of the OHIF Viewer within XNAT has been highly successful and numerous additional and enhanced tools have been created in a programme started in 2017 that is still ongoing. The software has been downloaded more than 3700 times during the course of the development work reported here, demonstrating the impact of the work. Conclusions: The OHIF open-source, zero-footprint web viewer has been incorporated into the XNAT platform and is now used at many institutions worldwide. Further innovations are envisaged in the near future

    Optical imaging and spectroscopy for the study of the human brain: status report.

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    This report is the second part of a comprehensive two-part series aimed at reviewing an extensive and diverse toolkit of novel methods to explore brain health and function. While the first report focused on neurophotonic tools mostly applicable to animal studies, here, we highlight optical spectroscopy and imaging methods relevant to noninvasive human brain studies. We outline current state-of-the-art technologies and software advances, explore the most recent impact of these technologies on neuroscience and clinical applications, identify the areas where innovation is needed, and provide an outlook for the future directions
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