9,118 research outputs found

    Design optimization of high-performance electrodynamic actuators for use in a cryogenically cooled telescope

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    An analysis and optimization of a mirror-actuator system for large excursion/high-frequency chopping is developed. The results of this analysis, combined with laboratory measurements of a prototype actuator operating at cryogenic temperatures, allow performance predictions to be made for a real system utilizing this technology

    Promoting Creativity in the Secondary Design and Technology Classroom in England

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    This study explores the use and implications of biomimicry as a design method in a secondary school Design and Technology classroom in England. The study’s aim was to explore biomimicry as one of the design approaches in a Design and Technology classroom. The goal of this research was to develop an appropriate teaching strategy for including biomimicry in the design process as a means for encouraging students to “use a variety of approaches to generate creative ideas and avoid stereotypical responses when responding to design briefs” (DfE, 2013, p. 2). The Biomimicry approach takes inspiration from natural solutions adopted by nature and imitates the concepts when designing products. Working with a class of year 9 pupils (aged 13 - 14) the research team introduced the principles of biomimicry, which was chosen as an innovative approach for promoting creativity. This action research took a qualitative approach to gain insights into pupils' thought process as they applied biomimicry in the given design brief. Action Research was used to understand if the introduction of biomimicry as an intervention would develop pupils’ creativity. The data that was used for analysis includes responses to open-ended questions, drawings, and artefacts. The findings of the study show that with the support of teachers, pupils used inspirations from nature in their design and make tasks to creatively think through and create original artefacts that meet an identified design need. The biomimicry approach was embraced by pupils who developed a range of nature inspired designs. The paper also presents interesting findings on pupils’ knowledge and learning process through demonstration of acquired skills of originality and creativity represented through interventions in natur

    Assessment of the feasibility of an ultra-low power, wireless digital patch for the continuous ambulatory monitoring of vital signs.

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    BACKGROUND AND OBJECTIVES: Vital signs are usually recorded at 4–8 h intervals in hospital patients, and deterioration between measurements can have serious consequences. The primary study objective was to assess agreement between a new ultra-low power, wireless and wearable surveillance system for continuous ambulatory monitoring of vital signs and a widely used clinical vital signs monitor. The secondary objective was to examine the system's ability to automatically identify and reject invalid physiological data. SETTING: Single hospital centre. PARTICIPANTS: Heart and respiratory rate were recorded over 2 h in 20 patients undergoing elective surgery and a second group of 41 patients with comorbid conditions, in the general ward. OUTCOME MEASURES: Primary outcome measures were limits of agreement and bias. The secondary outcome measure was proportion of data rejected. RESULTS: The digital patch provided reliable heart rate values in the majority of patients (about 80%) with normal sinus rhythm, and in the presence of abnormal ECG recordings (excluding aperiodic arrhythmias such as atrial fibrillation). The mean difference between systems was less than ±1 bpm in all patient groups studied. Although respiratory data were more frequently rejected as invalid because of the high sensitivity of impedance pneumography to motion artefacts, valid rates were reported for 50% of recordings with a mean difference of less than ±1 brpm compared with the bedside monitor. Correlation between systems was statistically significant (p<0.0001) for heart and respiratory rate, apart from respiratory rate in patients with atrial fibrillation (p=0.02). CONCLUSIONS: Overall agreement between digital patch and clinical monitor was satisfactory, as was the efficacy of the system for automatic rejection of invalid data. Wireless monitoring technologies, such as the one tested, may offer clinical value when implemented as part of wider hospital systems that integrate and support existing clinical protocols and workflows

    Spatio-temporal feature extraction in sensory electroneurographic signals

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    The recording and analysis of peripheral neural signal can provide insight for various prosthetic and bioelectronics medicine applications. However, there are few studies that investigate how informative features can be extracted from population activity electroneurographic (ENG) signals. In this study, five feature extraction frameworks were implemented on sensory ENG datasets and their classification performance was compared. The datasets were collected in acute rat experiments where multi-channel nerve cuffs recorded from the sciatic nerve in response to proprioceptive stimulation of the hindlimb. A novel feature extraction framework, which incorporates spatio-temporal focus and dynamic time warping, achieved classification accuracies above 90% while keeping a low computational cost. This framework outperformed the remaining frameworks tested in this study and has improved the discrimination accuracy of the sensory signals. Thus, this study has extended the tools available to extract features from sensory population activity ENG signals. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’

    Classical and quantum wormholes in a flat Λ\Lambda-decaying cosmology

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    We study the classical and quantum wormholes for a flat {\it Euclidean} Friedmann-Robertson-Walker metric with a perfect fluid including an ordinary matter source plus a source playing the role of dark energy (decaying cosmological term). It is shown that classical wormholes exist for this model and the quantum version of such wormholes are consistent with the Hawking-Page conjecture for quantum wormholes as solutions of the Wheeler-DeWitt equation.Comment: 8 pages, 4 figures, accepted for publication in IJT

    Correlação entre os métodos Mehlich 1, Melich 3 e resina para anålise de P e K em solos dos tabuleiros Csoterios.

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    A pesquisa apresenta os resultados da comparação entre o Mehlich-3 (M3) e a resina com o Mehlich-1 (M1) em solos dos tabuleiros costeiros.bitstream/CPATC/20018/1/bp_33.pd
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