1,212 research outputs found

    Vehicle Battery Safety Roadmap Guidance

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    The safety of electrified vehicles with high capacity energy storage devices creates challenges that must be met to assure commercial acceptance of EVs and HEVs. High performance vehicular traction energy storage systems must be intrinsically tolerant of abusive conditions: overcharge, short circuit, crush, fire exposure, overdischarge, and mechanical shock and vibration. Fail-safe responses to these conditions must be designed into the system, at the materials and the system level, through selection of materials and safety devices that will further reduce the probability of single cell failure and preclude propagation of failure to adjacent cells. One of the most important objectives of DOE's Office of Vehicle Technologies is to support the development of lithium ion batteries that are safe and abuse tolerant in electric drive vehicles. This Roadmap analyzes battery safety and failure modes of state-of-the-art cells and batteries and makes recommendations on future investments that would further DOE's mission

    On Semantic Similarity in Video Retrieval

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    Integrating e-learning into postgraduate radiotherapy and oncology education: a case study

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    Training health professionals within University environments has traditionally focused on face-to-face methods. Practitioners working within the UK National Health Service (NHS) have found it difficult to gain leave from work to attend for study due to the demands of the NHS and staff shortages. In response, we developed a distance e learning course to match our current traditional taught programme.The first e learning module (a research methods module) was comparable in content to the traditional taught module, and developed to incorporate a formative assessment design throughout; embodying the Constructivist approach and the principle of assessment for learning. We evaluated student experiences with the e learning module using a pre and post module questionnaire, with the taught cohort used as a comparison. We tested the importance of support, levels of information technology (IT) skills, preferences for e learning and intrinsic motivation. The results identified that highly satisfied e learning students were more likely to report a preference for e learning initially, show higher levels of intrinsic motivation and report good support from tutors and fellow students. This article discusses the development and evaluation of the pilot module and some of the lessons learned from providing e learning to health workers

    Developing and validating a cardiovascular risk score for patients in the community with prior cardiovascular disease

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    OBJECTIVE: Patients with atherosclerotic cardiovascular disease (CVD) vary significantly in their risk of future CVD events; yet few clinical scores are available to aid assessment of risk. We sought to develop a score for use in primary care that estimates short-term CVD risk in these patients. METHODS: Adults aged <80 years with prior CVD were identified from a New Zealand primary care cohort study (PREDICT), and linked to national mortality, hospitalisation and dispensing databases. A Cox model with an outcome of myocardial infarction, stroke or CVD death within 2 years was developed. External validation was performed in a cohort from the UK. RESULTS: 24 927 patients, 63% men, 63% European, median age 65 years (IQR 58-72 years), experienced 1480 CVD events within 2 years after a CVD risk assessment. A risk score including ethnicity, comorbidities, body mass index, creatine creatinine and treatment, in addition to established risk factors used in primary prevention, predicted a median 2-year CVD risk of 5.0% (IQR 3.5%-8.3%). A plot of actual against predicted event rates showed very good calibration throughout the risk range. The score performed well in the UK cohort but overestimated risk for those at highest risk, who were predominantly patients defined as having heart failure. CONCLUSIONS: The PREDICT-CVD secondary prevention score uses routine measurements from clinical practice that enable it to be implemented in a primary care setting. The score will facilitate risk communication between primary care practitioners and patients with prior CVD, particularly as a resource to show the benefit of risk factor modification

    Identification and characterization of Rhodopseudomonas palustris TIE-1 hopanoid biosynthesis mutants

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    Hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic hopanoid lipids. Based on the phylogenetic distribution of hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. However, our ability to interpret them ultimately depends on understanding the physiological roles of hopanoids in modern bacteria. Toward this end, we set out to identify genes required for hopanoid biosynthesis in the anoxygenic phototroph Rhodopseudomonas palustris TIE-1 to enable selective control of hopanoid production. We attempted to delete 17 genes within a putative hopanoid biosynthetic gene cluster to determine their role, if any, in hopanoid biosynthesis. Two genes, hpnH and hpnG, are required to produce both bacteriohopanetetrol and aminobacteriohopanetriol, whereas a third gene, hpnO, is required only for aminobacteriohopanetriol production. None of the genes in this cluster are required to exclusively synthesize bacteriohopanetetrol, indicating that at least one other hopanoid biosynthesis gene is located elsewhere on the chromosome. Physiological studies with the different deletion mutants demonstrated that unmethylated and C_30 hopanoids are sufficient to maintain cytoplasmic but not outer membrane integrity. These results imply that hopanoid modifications, including methylation of the A-ring and the addition of a polar head group, may have biologic functions beyond playing a role in membrane permeability

    Rescaling Egocentric Vision: Collection, Pipeline and Challenges for EPIC-KITCHENS-100

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    This paper introduces the pipeline to extend the largest dataset in egocentric vision, EPIC-KITCHENS. The effort culminates in EPIC-KITCHENS-100, a collection of 100 hours, 20M frames, 90K actions in 700 variable-length videos, capturing long-term unscripted activities in 45 environments, using head-mounted cameras. Compared to its previous version (Damen in Scaling egocentric vision: ECCV, 2018), EPIC-KITCHENS-100 has been annotated using a novel pipeline that allows denser (54% more actions per minute) and more complete annotations of fine-grained actions (+128% more action segments). This collection enables new challenges such as action detection and evaluating the “test of time”—i.e. whether models trained on data collected in 2018 can generalise to new footage collected two years later. The dataset is aligned with 6 challenges: action recognition (full and weak supervision), action detection, action anticipation, cross-modal retrieval (from captions), as well as unsupervised domain adaptation for action recognition. For each challenge, we define the task, provide baselines and evaluation metrics.Published versionResearch at Bristol is supported by Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Program (DTP), EPSRC Fellowship UMPIRE (EP/T004991/1). Research at Catania is sponsored by Piano della Ricerca 2016-2018 linea di Intervento 2 of DMI, by MISE - PON I&C 2014-2020, ENIGMA project (CUP: B61B19000520008) and by MIUR AIM - Attrazione e Mobilita Internazionale Linea 1 - AIM1893589 - CUP E64118002540007

    A simple inverse method for the interpretation of pumped flowing fluid electrical conductivity logs

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    Pumped flowing fluid electrical conductivity (FFEC) logs, also known as pumped borehole dilution testing, is an experimentally easy‐to‐perform approach to evaluating vertical variations in the hydraulic conductivity of an aquifer. In contrast to the simplicity of the logging equipment, analysis of the data is complex and laborious. Current methods typically require repeated solution of the advection‐dispersion equation (ADE) for describing the flow in the borehole and comparison with the experimental results. In this paper, we describe a direct solution for determining borehole fluid velocity that bypasses the need for complex numerical computation and repetitive optimization. The method rests on the observation that, while solving the ADE for concentration profile in the borehole (as required for modeling and combined methods) is computationally challenging, the solution for flow distribution along the length of the borehole given concentration data is straightforward. The method can accommodate varying borehole diameters, and uses the fact that multiple profiles are taken in the standard logging approach to reduce the impact of noise. Data from both a simulated borehole and from a field test are successfully analyzed. The method is implemented in a spreadsheet, which is available as supporting information material to this paper
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