2,069 research outputs found

    Stochastic method for in-situ damage analysis

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    Based on the physics of stochastic processes we present a new approach for structural health monitoring. We show that the new method allows for an in-situ analysis of the elastic features of a mechanical structure even for realistic excitations with correlated noise as it appears in real-world situations. In particular an experimental set-up of undamaged and damaged beam structures was exposed to a noisy excitation under turbulent wind conditions. The method of reconstructing stochastic equations from measured data has been extended to realistic noisy excitations like those given here. In our analysis the deterministic part is separated from the stochastic dynamics of the system and we show that the slope of the deterministic part, which is linked to mechanical features of the material, changes sensitively with increasing damage. The results are more significant than corresponding changes in eigenfrequencies, as commonly used for structural health monitoring.Comment: This paper is accepted by European Physical Journal B on November 2. 2012. 5 pages, 5 figures, 1 tabl

    Serum glucose concentration and lipid profile in racing horses

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    The aim of the present work was to evaluate serum glucose concentration and lipid profile in racing horses in Iraq. Blood samples were collected from the jugular vein of 92 clinically healthy racing horses (males and females, Arabian and Cross bred), 2-8 years old at Equestrian Club, Baghdad. Investigations included serum measurements of glucose (sg) and lipid profile parameters; total cholesterol (TC), Triglyceride (TG), high density lipoprotein- cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C) and the atherogenic ratio (LDL-C/HDL-C), in order to register the normal ranges and mean values of these measured parameters in Iraqi healthy racing horses. Results showed that the range and mean values ± standard error of sg were: 33.3 – 6.71 mmol/l and 5.17±0.07 mmol/l, respectively, whereas the TC was 2.07 – 4.22 mmol/l and 3.01±0.05 mmol/l, TG 0.6 – 1.47 mmol/l and 1.06±0.02 mmol/l, HDL-C 0.93 – 2.25 mmol/l and 1.50±0.03 mmol/l, LDL-C 0.10 – 2.12 mmol/l and 0.91±0.04 mmol/l, VLDL-C 0.31 -0.67 mmol/l and 0.55±0.02 mmol/l, respectively and the atherogenic ratio 0.66±0.03. The data present reference values and mean ± SE for sg and lipid profile parameters in healthy racing horses in Baghdad

    DESIGN OF BLOCK-BACKSTEPPING CONTROLLER TO BALL AND ARC SYSTEM BASED ON ZERO DYNAMIC THEORY

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    This paper develops a proposed block-backstepping algorithm for balancing and tracking control of ball and arc system. Two block-backstepping designs have been presented; one from the linearized model and other from a nonlinear model of the considered underactuated system. Also, two main control objectives have been achieved; firstly to bring the ball to rest on the top of the arc and secondly to make the cart track a defined reference trajectory. Moreover, integral action is included in the developed block-backstepping control law to improve the steadystate characteristics and to enhance the robustness of the overall system. Additionally, the internal stability of the nonlinear system has been analyzed using zero dynamic criteria to guarantee the global asymptotic stability at the desired equilibrium point. The performance of the designed control algorithm is assessed via simulated results. The results show that the block-backstepping controller designed for nonlinear system gives better transient performance than that designed for the linear system. Also, the nonlinear controller can cope with larger initial angular ball position without loss of stability

    Injury Severity Score coding: Data analyst v. emerging m-health technology

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    Background. The cost of Abbreviated Injury Scale (AIS) coding has limited its utility in areas of the world with the highest incidence of trauma. We hypothesised that emerging mobile health (m-health) technology could offer a cost-effective alternative to the current goldstandard AIS mechanism in a high-volume trauma centre in South Africa.Methods. A prospectively collected sample of consecutive patients admitted following a traumatic injury that required an operation during a 1-month period was selected for the study. AISs and Injury Severity Scores (ISSs) were generated by clinician-entered data using an m-health application (ISS eTHR) as well as by a team of AIS coders at Vancouver General Hospital, Canada (ISS VGH). Rater agreements for ISSs were analysed using Bland-Altman plots with 95% limits of agreement (LoA) and kappa statistics of the ISSs grouped into ordinal categories. Reliability was analysed using a two-way mixed-model intraclass correlation coefficient (ICC). Calibration and discrimination of univariate logistic regression models built to predict in-hospital complications using ISSs coded by the two methods were also compared.Results. Fifty-seven patients were managed operatively during the study period. The mean age of the cohort was 27.2 years (range 14 - 62), and 96.3% were male. The mechanism of injury was penetrating in 93.4% of cases, of which 52.8% were gunshot injuries. The LoA fell within –8.6 - 9.4. The mean ISS difference was 0.4 (95% CI –0.8 - 1.6). The kappa statistic was 0.53. The ICC of the individual ISS was 0.88 (95% CI 0.81 - 0.93) and the categorical ISS was 0.81 (95% CI 0.68 - 0.87). Model performance to predict in-hospital complications using either the ISS eTHR or the ISS VGH was equivalent.Conclusions. ISSs calculated by the eTHR and gold-standard coding were comparable. Emerging m-health technology provides a costeffective alternative for injury severity scoring

    Urban Growth Prediction Using Cellular Automata Markov: A Case Study Using Sulaimaniya City in the Kurdistan Region of North Iraq

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    Many cities in the Kurdistan Region have witnessed a rapid change in land use during the last two decades. Geographic information systems (GIS) and remote sensing have been broadly utilized to monitor and detect urban growth prediction. In this paper, three Landsat TM 5 and one Landsat 8 of Sulaimaniya city were used to identify and develop an urban growth map for 1991, 1998, 2006 and 2014. A supervised classification approach was applied; in order to predict urban growth, the Markov chain and CA-Markov models were used. The result demonstrates that validation of CA-Markov to forecast 2006 land cover map is ineffective in reasonably predicting land coverage for this time period; however this model had significant validation for the year 2014 and also has a good forecast power for 2024. Keywords Land Use Change/Cover, Urban Growth Prediction, Supervised Classification, Markov Chain, CA-Markov, Validation

    Transauricular nerve stimulation in acute ischaemic stroke requiring mechanical thrombectomy: Protocol for a phase 2A, proof-of-concept, sham-controlled randomised trial.

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    BACKGROUND: Labile blood pressure after acute ischaemic stroke requiring mechanical thrombectomy is independently associated with poor patient outcomes. OBJECTIVES: This study protocol describes is designed to determine whether transauricular nerve stimulation, improves baroreflex sensitivity, reduces blood pressure variability in the first 24 hours after acute ischaemic stroke requiring mechanical thrombectomy. DESIGN: PHASE 2A, PROOF-OF-CONCEPT, SHAM-CONTROLLED RANDOMISED TRIAL: Methods and Analysis: 36 individuals undergoing mechanical thrombectomy for acute ischaemic stroke with established hypertension aged >18 years will be randomly allocated to receive bilateral active or sham transauricular nerve stimulation for the duration of the mechanical thrombectomy procedure (AffeX-CT/001 investigational device). The intervention will be repeated for 1h the morning following the mechanical thrombectomy. Non-invasive blood pressure will be measured ≥2h for 24h after mechanical thrombectomy. Holter electrocardiographic monitoring will be recorded during transauricular nerve stimulation. Participants, clinicians and investigators will be masked to treatment allocations. The primary outcome will be the coefficient of variation of systolic blood pressure. Secondary outcomes include additional estimates of blood pressure variability and time/frequency-domain measures of autonomic cardiac modulation An adjusted sample size of 36 patients is required to have a 90% chance of detecting, as significant at the 5% level, a difference in the coefficient of variation in systolic blood pressure of 5±4mmHg between sham and active stimulation [assuming 5% non-compliance rate in each group]. Ethics: confirmed on 16 March 2023 by HRA and Health and Care Research Wales ethics committee (reference 23/WA/0013). DISCUSSION: This study will provide proof-of-concept data that examines whether non-invasive autonomic neuromodulation can be used to favourably modify blood pressure and autonomic control after acute ischaemic stroke requiring mechanical thrombectomy. TRIAL REGISTRATION: Trial registration number: NCT05417009

    H-alpha Imaging of Early-type (Sa-Sab) Spiral Galaxies II. Global Properties

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    New results, based on one of the most comprehensive H-alpha imaging surveys of nearby Sa-Sab spirals completed to date, reveals early-type spirals to be a diverse group of galaxies that span a wide range in massive star formation rates. While the majority of Sa-Sab galaxies in our sample are forming stars at a modest rate, a significant fraction (~29%) exhibit star formation rates greater than 1 M(solar/yr), rivaling the most prolifically star forming late-type spirals. A similar diversity is apparent in the star formation history of Sa-Sab spirals as measured by their H-alpha equivalent widths. Consistent with our preliminary results presented in the first paper in this series, we find giant HII regions (L(H-alpha)>10^{39}erg/s) in the disks of 37% of early-type spirals. We suspect that recent minor mergers or past interactions are responsible for the elevated levels of H-alpha emission and perhaps, for the presence of giant HII regions in these galaxies.Comment: 42 pages and 17 figures (6 in jpg format, available upon request from the authors as postscript); to appear in the June issue of A

    3,6-Dimethyl-1-phenyl-1H,4H-pyrano[2,3-c]pyrazol-4-one

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    The title compound, C14H12N2O2, is almost planar with an r.m.s. deviation for all non-H atoms of 0.038 Å. The observed planarity is rationalized in terms of a close intra­molecular C—H⋯O inter­action. Supra­molecular layers, two mol­ecules thick and with a step topology, are formed in the crystal packing via C—H⋯O contacts involving the carbonyl O atom, which accepts two such bonds, and π–π inter­actions between the components of the fused ring system and the phenyl ring of inversion-related mol­ecules [centroid–centroid distances = 3.6819 (13) and 3.6759 (12) Å]
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