289 research outputs found

    Noise source characteristics in the ISO 362 vehicle pass-by noise test: literature review

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    Since many people are exposed to road traffic noise in urban areas, current legislation aims to limit vehicle noise emissions. In Europe, the vehicle pass-by noise test is implemented according to the international standard ISO 362. As a result of more recent investigations of urban traffic, a revision to the ISO 362 standard has been proposed that includes a constantspeed test in addition to the traditional accelerated test in order to determine the pass-by noise value. To ensure compliance with the pass-by noise test vehicle manufacturers and suppliers must quantify vehicle noise source characteristics during the design stage of the vehicle. In addition, predictive tools need to be available during the product development phase in order to estimate the final pass-by noise level. In this paper an extensive literature survey is presented of noise source characteristics in the ISO 362 vehicle pass-by noise test. Vehicle pass-by noise is analysed in the time and frequency domains and a ranking of the noise source contributions is established. The characteristics of the four major noise sources (engine, intake system, exhaust system, tyre/road system) contributing to pass-by noise as well as current prediction methods are reviewed

    Peripheral sensory neuropathy is associated with altered postocclusive reactive hyperemia in the diabetic foot

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    Objective: This study examined whether the presence of peripheral sensory neuropathy or cardiac autonomic deficits is associated with postocclusive reactive hyperemia (reflective of microvascular function) in the diabetic foot. Research design and methods: 99 participants with type 2 diabetes were recruited into this crosssectional study. The presence of peripheral sensory neuropathy was determined with standard clinical tests and cardiac autonomic function was assessed with heart rate variation testing. Postocclusive reactive hyperemia was measured with laser Doppler in the hallux. Multiple hierarchical regression was performed to examine relationships between neuropathy and the peak perfusion following occlusion and the time to reach this peak. Results: Peripheral sensory neuropathy predicted 22% of the variance in time to peak following occlusion (p<0.05), being associated with a slower time to peak but was not associated with the magnitude of the peak. Heart rate variation was not associated with the postocclusive reactive hyperemia response. Conclusions: This study found an association between the presence of peripheral sensory neuropathy in people with diabetes and altered microvascular reactivity in the lower limb

    Investigating the feasibility of MRI auto-segmentation for Image Guided Brachytherapy

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    A feasibility study has been performed to investigate the viability of applying auto-segmentation methods to the delineation of regions of interest (ROIs) in the treatment of cervical cancer using Image Guided Brachytherapy (IGBT). The introduction of auto-segmentation in IGBT aims to improve outlining consistency while improving patient experience by reducing the time taken to plan treatments. An anonymised database of MRI images and corresponding clinical ROI outlines was curated, categorised by brachytherapy treatment applicator type. This database was then used to train and test an autosegmentation model to contour the Bladder using three established algorithms, U-Net, SegNet and PSPNet. Quantitatively the U-Net model was found to produce contours geometrically closest to the original manual contours with a mean Dice Similarity Coefficient (DSC) of 0.942 compared to 0.919 and 0.879 for SegNet and PSPNet respectively and a mean Mean Distance to Agreement (mDTA) value of 0.46mm compared to 0.66mm and 0.89mm for SegNet and PSPNet. Visual assessment of the resulting contours demonstrated good agreement for the U-Net and SegNet produced outlines, particularly in the region of clinical significance, with greater variations seen at the extremities of the contour. In conclusion this feasibility study has shown that auto-segmentation methods can be applied to MRI IGBT contour delineation with a method established to facilitate further investigations in the application to all clinical ROIs and brachytherapy applicator types

    ‘New Medicine Service’: supporting adherence in people starting a new medication for a long-term condition: 26-week follow-up of a pragmatic randomised controlled trial

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    OBJECTIVE: To examine the effectiveness and cost-effectiveness of the community pharmacy New Medicine Service (NMS) at 26 weeks. METHODS: Pragmatic patient-level parallel randomised controlled trial in 46 English community pharmacies. 504 participants aged ≄14, identified in the pharmacy when presenting a prescription for a new medicine for predefined long-term conditions, randomised to receive NMS (n=251) or normal practice (n=253) (NMS intervention: 2 consultations 1 and 2 weeks after prescription presentation). Adherence assessed through patient self-report at 26-week follow-up. Intention-to-treat analysis employed. National Health Service (NHS) costs calculated. Disease-specific Markov models estimating impact of non-adherence combined with clinical trial data to calculate costs per extra quality-adjusted life-year (QALY; NHS England perspective). RESULTS: Unadjusted analysis: of 327 patients still taking the initial medicine, 97/170 (57.1%) and 103/157 (65.6%) (p=0.113) patients were adherent in normal practice and NMS arms, respectively. Adjusted intention-to-treat analysis: adherence OR 1.50 (95% CI 0.93 to 2.44, p=0.095), in favour of NMS. There was a non-significant reduction in 26-week NHS costs for NMS: -ÂŁ104 (95% CI -ÂŁ37 to ÂŁ257, p=0.168) per patient. NMS generated a mean of 0.04 (95% CI -0.01 to 0.13) more QALYs per patient, with mean reduction in lifetime cost of -ÂŁ113.9 (-1159.4, 683.7). The incremental cost-effectiveness ratio was -ÂŁ2758/QALY (2.5% and 97.5%: -38 739.5, 34 024.2. NMS has an 89% probability of cost-effectiveness at a willingness to pay of ÂŁ20 000 per QALY. CONCLUSIONS: At 26-week follow-up, NMS was unable to demonstrate a statistically significant increase in adherence or reduction in NHS costs, which may be attributable to patient attrition from the study. Long-term economic evaluation suggested NMS may deliver better patient outcomes and reduced overall healthcare costs than normal practice, but uncertainty around this finding is high. TRIAL REGISTRATION NUMBER: NCT01635361, ISRCTN23560818, ISRCTN23560818, UKCRN12494

    Endovascular treatment of thoracoabdominal aortic aneurysm: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Thoracoabdominal aortic aneurysms usually present in elderly patients with serious renal, pulmonary, cerebral, or cardiac comorbidities that pose a great challenge to the attending surgeon. Endovascular techniques for the treatment of thoracoabdominal aneurysms are not yet widely used due to limitations associated with them, such as spinal and visceral ischemia.</p> <p>Case presentation</p> <p>An 87-year-old Caucasian man with a symptomatic Crawford type I thoracoabdominal aortic aneurysm was treated successfully with a long tube stent graft using endovascular techniques and without any complication in follow-up examinations. The stent was placed distal to the left subclavian artery, and proximal to the celiac axis.</p> <p>Conclusion</p> <p>The use of endovascular stents for long segment thoracoabdominal aortic aneurysms needs to undergo clinical investigation to determine whether this procedure decreases morbidity and mortality rates.</p

    The sizes, masses and specific star formation rates of massive galaxies at 1.3 &lt; z &lt; 1.5: strong evidence in favour of evolution via minor mergers

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    We report the results of a comprehensive study of the relationship between galaxy size, stellar mass and specific star-formation rate (sSFR) at redshifts 1.3= 6x10^10 Msun), spectroscopic sample from the UKIDSS Ultra-deep Survey (UDS), with accurate stellar-mass measurements derived from spectro photometric fitting, we find that at z~1.4 the location of massive galaxies on the size-mass plane is determined primarily by their sSFR. At this epoch we find that massive galaxies which are passive (sSFR <= 0.1 Gyr^-1) follow a tight size-mass relation, with half-light radii a factor f=2.4+/-0.2 smaller than their local counterparts. Moreover, amongst the passive sub-sample we find no evidence that the off-set from the local size-mass relation is a function of stellar population age. Based on a sub-sample with dynamical mass estimates we also derive an independent estimate of f=2.3+/-0.3 for the typical growth in half-light radius between z~1.4 and the present day. Focusing on the passive sub-sample, we conclude that to produce the necessary evolution predominantly via major mergers would require an unfeasible number of merger events and over populate the high-mass end of the local stellar mass function. In contrast, we find that a scenario in which mass accretion is dominated by minor mergers can produce the necessary evolution, whereby an increase in stellar mass by a factor of ~2, accompanied by an increase in size by a factor of ~3.5, is sufficient to reconcile the size-mass relation at z~1.4 with that observed locally. Finally, we note that a significant fraction (44+/-12%) of the passive galaxies in our sample have a disk-like morphology, providing additional evidence that separate physical processes are responsible for the quenching of star-formation and the morphological transformation of massive galaxies (abridged).Comment: 21 pages, 11 figures, accepted for publication in MNRAS. Replaced to match accepted versio

    What affected UK adults’ adherence to medicines during the COVID-19 pandemic? Cross-sectional survey in a representative sample of people with long-term conditions

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    AimMedicines non-adherence is associated with poorer outcomes and higher costs. COVID-19 affected access to healthcare, with increased reliance on remote methods, including medicines supply. This study aimed to identify what affected people’s adherence to medicines for long-term conditions (LTCs) during the pandemic.Subject and methodsCross-sectional online survey of UK adults prescribed medicines for LTCs assessing self-reported medicines adherence, reasons for non-adherence (using the capability, opportunity and motivation model of behaviour [COM-B]), medicines access and COVID-19-related behaviours.ResultsThe 1746 respondents reported a mean (SD) of 2.5 (1.9) LTCs, for which they were taking 2.4 (1.9) prescribed medicines, 525 (30.1%) reported using digital tools to support ordering or taking medicines and 22.6% reported medicines non-adherence. No access to at least one medicine was reported by 182 (10.4%) respondents; 1048 (60.0%) reported taking at least one non-prescription medicine as a substitute; 409 (23.4%) requested emergency supply from pharmacy for at least one medicine. Problems accessing medicines, being younger, male, in the highest socioeconomic group and working were linked to poorer adherence. Access problems were mostly directly or indirectly related to the COVID-19 pandemic. Respondents were generally lacking in capabilities and opportunities, but disruptions to habits (automatic motivation) was the major reason for non-adherence.ConclusionNavigating changes in how medicines were accessed, and disruption of habits during the COVID-19 pandemic, was associated with suboptimal adherence. People were resourceful in overcoming barriers to access. Solutions to support medicines-taking need to take account of the multiple ways that medicines are prescribed and supplied remotely

    Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers

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    We present new improved constraints on the Hubble parameter H(z) in the redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic evolution of early-type galaxies as a function of redshift. We extract a large sample of early-type galaxies (\sim11000) from several spectroscopic surveys, spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We select the most massive, red elliptical galaxies, passively evolving and without signature of ongoing star formation. Those galaxies can be used as standard cosmic chronometers, as firstly proposed by Jimenez & Loeb (2002), whose differential age evolution as a function of cosmic time directly probes H(z). We analyze the 4000 {\AA} break (D4000) as a function of redshift, use stellar population synthesis models to theoretically calibrate the dependence of the differential age evolution on the differential D4000, and estimate the Hubble parameter taking into account both statistical and systematical errors. We provide 8 new measurements of H(z) (see Tab. 4), and determine its change in H(z) to a precision of 5-12% mapping homogeneously the redshift range up to z \sim 1.1; for the first time, we place a constraint on H(z) at z \neq 0 with a precision comparable with the one achieved for the Hubble constant (about 5-6% at z \sim 0.2), and covered a redshift range (0.5 < z < 0.8) which is crucial to distinguish many different quintessence cosmologies. These measurements have been tested to best match a \Lambda CDM model, clearly providing a statistically robust indication that the Universe is undergoing an accelerated expansion. This method shows the potentiality to open a new avenue in constrain a variety of alternative cosmologies, especially when future surveys (e.g. Euclid) will open the possibility to extend it up to z \sim 2.Comment: 34 pages, 15 figures, 6 tables, published in JCAP. It is a companion to Moresco et al. (2012b, http://arxiv.org/abs/1201.6658) and Jimenez et al. (2012, http://arxiv.org/abs/1201.3608). The H(z) data can be downloaded at http://www.physics-astronomy.unibo.it/en/research/areas/astrophysics/cosmology-with-cosmic-chronometer
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