21,952 research outputs found

    Results of winglet development studies for DC-10 derivatives

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    The results of investigations into the application of winglets to the DC-10 aircraft are presented. The DC-10 winglet configuration was developed and its cruise performance determined in a previous investigation. This study included high speed and low speed wind tunnel tests to evaluate aerodynamic characteristics, and a subsonic flutter wind tunnel test with accompanying analysis and evaluation of results. Additionally, a configuration integration study employed the results of the wind tunnel studies to determine the overall impact of the installation of winglets on the DC-10 aircraft. Conclusions derived from the high speed and low speed tests indicate that the winglets had no significant effects on the DC-10 stability characteristics or high speed buffet. It was determined that winglets had a minimal effect on aircraft lift characteristics and improved the low speed aircraft drag under high lift conditions. The winglets affected the DC-10 flutter characteristics by reducing the flutter speed of the basic critical mode and introducing a new critical mode involving outer wing torsion and longitudinal bending. The overall impact of winglets was determined to be of sufficient benefit to merit flight evaluation

    Building Data-Driven Pathways From Routinely Collected Hospital Data:A Case Study on Prostate Cancer

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    Background: Routinely collected data in hospitals is complex, typically heterogeneous, and scattered across multiple Hospital Information Systems (HIS). This big data, created as a byproduct of health care activities, has the potential to provide a better understanding of diseases, unearth hidden patterns, and improve services and cost. The extent and uses of such data rely on its quality, which is not consistently checked, nor fully understood. Nevertheless, using routine data for the construction of data-driven clinical pathways, describing processes and trends, is a key topic receiving increasing attention in the literature. Traditional algorithms do not cope well with unstructured processes or data, and do not produce clinically meaningful visualizations. Supporting systems that provide additional information, context, and quality assurance inspection are needed. Objective: The objective of the study is to explore how routine hospital data can be used to develop data-driven pathways that describe the journeys that patients take through care, and their potential uses in biomedical research; it proposes a framework for the construction, quality assessment, and visualization of patient pathways for clinical studies and decision support using a case study on prostate cancer. Methods: Data pertaining to prostate cancer patients were extracted from a large UK hospital from eight different HIS, validated, and complemented with information from the local cancer registry. Data-driven pathways were built for each of the 1904 patients and an expert knowledge base, containing rules on the prostate cancer biomarker, was used to assess the completeness and utility of the pathways for a specific clinical study. Software components were built to provide meaningful visualizations for the constructed pathways. Results: The proposed framework and pathway formalism enable the summarization, visualization, and querying of complex patient-centric clinical information, as well as the computation of quality indicators and dimensions. A novel graphical representation of the pathways allows the synthesis of such information. Conclusions: Clinical pathways built from routinely collected hospital data can unearth information about patients and diseases that may otherwise be unavailable or overlooked in hospitals. Data-driven clinical pathways allow for heterogeneous data (ie, semistructured and unstructured data) to be collated over a unified data model and for data quality dimensions to be assessed. This work has enabled further research on prostate cancer and its biomarkers, and on the development and application of methods to mine, compare, analyze, and visualize pathways constructed from routine data. This is an important development for the reuse of big data in hospitals

    CBI limits on 31 GHz excess emission in southern HII regions

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    We have mapped four regions of the southern Galactic plane at 31 GHz with the Cosmic Background Imager. From the maps, we have extracted the flux densities for six of the brightest \hii regions in the southern sky and compared them with multi-frequency data from the literature. The fitted spectral index for each source was found to be close to the theoretical value expected for optically thin free-free emission, thus confirming that the majority of flux at 31 GHz is due to free-free emission from ionised gas with an electron temperature of ≈7000−8000\approx 7000-8000 K. We also found that, for all six sources, the 31 GHz flux density was slightly higher than the predicted value from data in the literature. This excess emission could be due to spinning dust or another emission mechanism. Comparisons with 100μ100 \mum data indicate an average dust emissivity of 3.3±1.7μ3.3\pm1.7 \muK (MJy/sr)−1^{-1}, or a 95 per cent confidence limit of <6.1μ<6.1 \muK (MJy/sr)−1^{-1}. This is lower than that found in diffuse clouds at high Galactic latitudes by a factor of ∼3−4\sim 3-4. The most significant detection (3.3σ3.3\sigma) was found in G284.3−0.3G284.3-0.3 (RCW49) and may account for up to ≈30\approx 30 per cent of the total flux density observed at 31 GHz. Here, the dust emissivity of the excess emission is 13.6±4.2μ13.6\pm4.2 \muK (MJy/sr)−1^{-1} and is within the range observed at high Galactic latitudes. Low level polarised emission was observed in all six sources with polarisation fractions in the range 0.3−0.60.3-0.6 per cent. This is likely to be mainly due to instrumental leakage and is therefore upper an upper limit to the free-free polarisation. It corresponds to an upper limit of ∼1\sim1 per cent for the polarisation of anomalous emission.Comment: Accepted in MNRAS. 12 pages, 10 figures, 5 table

    The properties of the gamma-ray blazars in the CJ-F VLBI sample

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    We present first results from the analysis of multi-epoch VLBI observations of the EGRET detected sources [9] in the CJ-F sample (Caltech Jodrell-Flat-spectrum, [10]). These objects form a subsample of 14 sources within the 293 AGN of the full CJ-F sample. 5 GHz VLBI snapshot observations of the CJ-F sources are continuously being performed in order to create a valid database for thorough statistical tests of pc-scale jet motion in AGN. All gamma-bright CJ-F AGN have been observed at least twice with the VLBA, which enables us to investigate jet component motions and paths. In particular, we concentrate on the analysis of those properties supposed to be essential for gamma-ray production, i.e., superluminal motion and bending. A paper discussing the possible relation between morphological changes and gamma-ray flaring/production is in preparation
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