8,702 research outputs found

    Haze in the Klang Valley of Malaysia

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    Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in the Klang Valley of Malaysia between December 1998 and December 2000. In addition 24-h PM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of the aerosol was determined. Periods of excessive haze were defined as 24-h average Bsp values greater than 150 Mm-1 and these occurred on a number of occasions, between May and September 1999, during May 2000, and between July and September 2000. The evidence for smoke being a significant contributor to aerosol during periods of excessive haze is discussed and includes features of the aerosol chemistry, the diurnal cycle of Bsp, and the coincidence of forest fires on Sumatra during the southwest (SW) monsoon period, as well as transport modelling for one week of the southwest Monsoon of 2000. The study highlights that whilst transboundary smoke is a major contributor to poor visibility in the Klang Valley, smoke from fires on Peninsular Malaysia is also a contributor, and at all times, the domestic source of secondary particle production is present

    A study on elasto-plastic impact friction

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    A purpose-built pendulum machine was used to study the oblique impact and the behaviour of the surface layers of a normalized low alloy steel subjected to the impact of hard [alpha]-alumina balls. The effect of relative tangential velocity on impulses, restitution coefficient and impact energy loss, was analysed. The morphology of the impact indentations was characterized and related to the impulses obtained. There was lip formation in the target material with ejection of a small fragile oxidized chip, at a certain critical sliding speed. The impact duration and the impulse ratio have maximum values. These values seem to be related to the critical angle of attack, common in abrasive and erosive ductile processes. The experimental results were compared with some impact models and theories.http://www.sciencedirect.com/science/article/B6V5B-3WRC3G0-4/1/41e4c5269f22928dae6bfa3fb640fd0

    Application of Micro Z-arm dough mixer in wheat research - Effect of protein addition on mixing properties of wheat dough

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    A Micro Z-arm mixer has been developed which needs only four grams of flour per test. The new instrument is suitable for screening new wheat cultivars in the early phase of selection on the basis of dough mixing properties. The micro-scale instrument can also be viewed as a valuable research tool for investigation of the structure/function relationships in flour and the effects of different ingredients and additives on rheological parameters. The effects of protein addition on mixing properties of wheat dough were studied. Alkali-soluble isolates and Osborne protein fractions extracted from wheat, corn-, rice germs and amaranth seeds were used as protein additives. Dough development time, maximum resistance of dough and resistance breakdown was calculated from recorded mixing curves. Results showed that the micro-scale equipment is sensitive enough for detection of the effect of less than 40 mg of protein addition on mixing parameters. The effects of additions depend on the type of proteins added to the wheat flour and the parameters calculated from the mixing curves

    Aplicación de las técnicas de suavizado en la variación negativa contingente (CNV)

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    El presente trabajo recoge de forma breve laproblemática de la estimación de la serial en series temporales de datos obtenidos en registros ERP. Se centra en aquellos componentes de frecuencia mis baja, como es el caso de la CNV: Sepropone la utilización alternativa de las técnicas de suavizado del Análisis Exploratorio de Datos (EDA), para mejorar la estimación obtenida, en comparación con la técnica del promediado simple de diferentes ensayos

    First Results from Betatron Matching Monitors Installed in the CERN PSB and SPS

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    In order to satisfy the tight emittance requirements of LHC, betatron matching monitors, based on multiturn beam profile measurements, have been proposed and installed in the CERN SPS and PSB. The SPS monitor is based on a OTR beam profile acquisition system and was installed two years ago and has since been tested. It helped to uncover a mismatch between PS and SPS. Experience and more results wil l be presented. The PSB monitor is based on a wire SEM and has been installed at the beginning of 1998. The first results presented here are very promising

    Data filtering in the readout of the CMS Electromagnetic Calorimeter

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    For an efficient data taking, the Electromagnetic Calorimeter (ECAL) data of the CMS experiment must be limited to 10\% of the full event size (1MB). Other requirements limit the average data size to 2kB per data acquisition link. These conditions imply a reduction factor of close to twenty on the data collected. The data filtering in the readout of the ECAL detector is discussed. Test beam data are used to study the digital filtering applied in the readout channels and a full detector simulation allows to estimate the energy thresholds to achieve the desired data suppression factor

    Prognostic implications of left ventricular global longitudinal strain in heart failure patients with narrow QRS complex treated with cardiac resynchronization therapy: a subanalysis of the randomized EchoCRT trial

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    Aim: Left ventricular (LV) global longitudinal strain (GLS) reflects LV systolic function and correlates inversely with the extent of LV myocardial scar and fibrosis. The present subanalysis of the Echocardiography Guided CRT trial investigated the prognostic value of LV GLS in patients with narrow QRS complex. Methods and results: Left ventricular (LV) global longitudinal strain (GLS) was measured on the apical 2-, 4- and 3-chamber views using speckle tracking analysis. Measurement of baseline LV GLS was feasible in 755 patients (374 with cardiac resynchronization therapy (CRT)-ON and 381 with CRT-OFF). The median value of LV GLS in the overall population was 7.9%, interquartile range 6.2–10.1%. After a mean follow-up period of 19.4 months, 95 patients in the CRT-OFF group and 111 in the CRT-ON group reached the combined primary endpoint of all-cause mortality and heart failure hospitalization. Each 1% absolute unit decrease in LV GLS was independently associated with 11% increase in the risk to reach the primary endpoint (Hazard ratio 1.11; 95% confidence interval 95% 1.04–1.17, P < 0.001), after adjusting for ischaemic cardiomyopathy and randomization treatment among other clinically relevant variables. When categorizing patients according to quartiles of LV GLS, the primary endpoint occurred more frequently in patients in the lowest quartile (<6.2%) treated with CRT-ON vs. CRT-OFF (45.6% vs. 28.7%, P = 0.009) whereas, no differences were observed in patients with LV GLS ≥6.2% treated with CRT-OFF vs. CRT-ON (23.7% vs. 24.5%, respectively; P  = 0.62). Conclusion: Low LV GLS is associated with poor outcome in heart failure patients with QRS width <130 ms, independent of randomization to CRT or not. Importantly, in the group of patients with the lowest LV GLS quartile, CRT may have a detrimental effect on clinical outcomes

    LBQS 1429-0053: a binary quasar rather than a lensed quasar

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    Very deep ESO/VLT FORS1 and ISAAC images, as well as HST NICMOS2 data are used to infer the nature of the quasar pair LBQS 1429-0053 A and B, either a binary quasar or a doubly-imaged lensed quasar. Direct search of a putative lensing galaxy is unsuccessful . Moreover, no galaxy overdensity close to the quasar pair is found. A weak shear analysis of the field also fails at detecting any concentration of dark matter and weakens the hypothesis of a dark lens. The only sign of a possible lens consists in a group of 5 objects at z~1, within a radius of 5'', from the quasar pair. Considering this group as the lensing potential does not allow to reproduce the image position and flux ratio of the quasars. Our deep R-band image shows a blue, extended object at the position of quasar A, which is consistent with either being the lensed quasar A host, or being an intervening galaxy at lower redshift. Unless future very deep optical images demonstrate that this object is actually the lensed host of LBQS 1429-0053, we conclude that there is very little evidence for this quasar being lensed. Therefore, we are led to declare LBQS 1429-0053 A and B a genuine binary quasar.Comment: 9 pages, 6 jpg images, accepted for publication in A&

    Evaluation of Near-Surface Air Temperature from Reanalysis over the United States and Ukraine: Application to Winter Wheat Yield Forecasting

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    In this work we evaluate the near-surface air temperature datasets from the ERA-Interim, JRA55, MERRA2, NCEP1, and NCEP2 reanalysis projects. Reanalysis data were first compared to observations from weather stations located on wheat areas of the United States and Ukraine, and then evaluated in the context of a winter wheat yield forecast model. Results from the comparison with weather station data showed that all datasets performed well (r2>0.95) and that more modern reanalysis such as ERAI had lower errors (RMSD ~ 0.9) than the older, lower resolution datasets like NCEP1 (RMSD ~ 2.4). We also analyze the impact of using surface air temperature data from different reanalysis products on the estimations made by a winter wheat yield forecast model. The forecast model uses information of the accumulated Growing Degree Day (GDD) during the growing season to estimate the peak NDVI signal. When the temperature data from the different reanalysis projects were used in the yield model to compute the accumulated GDD and forecast the winter wheat yield, the results showed smaller variations between obtained values, with differences in yield forecast error of around 2% in the most extreme case. These results suggest that the impact of temperature discrepancies between datasets in the yield forecast model get diminished as the values are accumulated through the growing season
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