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Correction Factor (correction + factor)
Selected AbstractsEvaluation of Humidity Correction Factor of Disruptive Discharge Voltage of Standard Sphere Air GapsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 1 2008Osamu Fujii Member Abstract The humidity correction method prescribed in the existing IEC standard is based on experimental data obtained under absolute humidity between 5 and 12 g/m3. A discussion on the humidity correction method is needed for higher absolute humidity regions, which is experienced during summer in Japan, and also throughout the year in tropical countries. The effect of absolute humidity on disruptive discharge voltages of standard sphere air gaps has been studied experimentally for several years under conditions of natural humidity, between 2 and 22 g/m3. In the cases of a.c. and lightning impulse voltage application, it was found that the existing IEC humidity correction method seems to be proper for most of the gap spacings studied under absolute humidity up to 22 g/m3. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Paracoccus denitrificans for the effluent recycling during continuous denitrification of liquid foodBIOTECHNOLOGY PROGRESS, Issue 3 2010Nils Tippkötter Abstract Nitrate is an undesirable component of several foods. A typical case of contamination with high nitrate contents is whey concentrate, containing nitrate in concentrations up to 25 l. The microbiological removal of nitrate by Paracoccus denitrificans under formation of harmless nitrogen in combination with a cell retention reactor is described here. Focus lies on the resource-conserving design of a microbal denitrification process. Two methods are compared. The application of polyvinyl alcohol-immobilized cells, which can be applied several times in whey feed, is compared with the implementation of a two step denitrification system. First, the whey concentrate's nitrate is removed by ion exchange and subsequently the eluent regenerated by microorganisms under their retention by crossflow filtration. Nitrite and nitrate concentrations were determined by reflectometric color measurement with a commercially available Reflectoquant® device. Correction factors for these media had to be determined. During the pilot development, bioreactors from 4 to 250 mg·L,1 and crossflow units with membrane areas from 0.02 to 0.80 m2 were examined. Based on the results of the pilot plants, a scaling for the exemplary process of denitrifying 1,000 tons per day is discussed. © 2010 American Institute of Chemical Engineers Biotechnol. Prog. 2010 [source] Effects of terrain smoothing on topographic shielding correction factors for cosmogenic nuclide-derived estimates of basin-averaged denudation ratesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 1 2009Kevin P. Norton Abstract Estimation of spatially averaged denudation rates from cosmogenic nuclide concentrations in sediments depends on the surface production rates, the scaling methods of cosmic ray intensities, and the correction algorithms for skyline, snow and vegetation shielding used to calculate terrestrial cosmogenic nuclide production. While the calculation of surface nuclide production and application of latitude, altitude and palaeointensity scaling algorithms are subjects of active research, the importance of additional correction for shielding by topographic obstructions, snow and vegetation is the subject of ongoing debate. The derivation of an additional correction factor for skyline shielding for large areas is still problematic. One important issue that has yet to be addressed is the effect of the accuracy and resolution of terrain representation by a digital elevation model (DEM) on topographic shielding correction factors. Topographic metrics scale with the resolution of the elevation data, and terrain smoothing has a potentially large effect on the correction of terrestrial cosmogenic nuclide production rates for skyline shielding. For rough, high-relief landscapes, the effect of terrain smoothing can easily exceed analytical errors, and should be taken into account. Here we demonstrate the effect of terrain smoothing on topographic shielding correction factors for various topographic settings, and introduce an empirical model for the estimation of topographic shielding factors based on landscape metrics. Copyright © 2008 John Wiley and Sons, Ltd. [source] Comparison of Proximal Isovelocity Surface Area Method and Pressure Half Time Method for Evaluation of Mitral Valve Area in Patients Undergoing Balloon Mitral ValvotomyECHOCARDIOGRAPHY, Issue 9 2005Thottuvelil Narayanan Sunil Roy M.D. Background: The pressure half time (PHT) method is unreliable for measurement of mitral valve area (MVA) immediately after valvotomy. The proximal isovelocity surface area (PISA) method has been used to derive mitral valve area in patients with mitral stenosis. The aim of our study was to compare PISA method and PHT method in patients undergoing percutaneous balloon mitral valvotomy (BMV). Methods: The PISA was recorded from the apex and MVA was calculated using continuity equation by the formula 2,r2 Vr/Vm, where 2,r2 is the hemispheric isovelocity area, Vr is the velocity at the radial distance "r" from the orifice, and Vm is the peak velocity. A plain angle correction factor (,)/180 was used to correct the inlet angle subtended by leaflet tunnel as a result of leaflet doming. Results: MVA calculated using PISA method (r = 0.5217, P < 0.0001, SE = 0.016) and PHT (r = 0.6652, P < 0.0001, SE = 0.017) correlated well with 2D method in patients with mitral stenosis before BMV. After BMV, MVA by PISA method correlated well with 2D planimetry (r = 0.5803, P < 0.0001, SE = 0.053) but PHT showed poor correlation (r = 0.1334, P = 0.199, SE = 0.036). The variability of measurement of MVA was most marked with PHT method in the post-BMV period. Conclusion: The PISA method correlates well with 2D planimetry in patients with mitral stenosis before and after BMV and is superior to the PHT method in the post-BMV period where the latter may be unreliable. [source] Impact of treatment provision on the epidemiological recording of root cariesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2000A. W. G. Walls The estimation of root caries prevalence and the identification of risk factors for decay depend upon the successful identification of carious lesions in epidemiological studies. Root surface restorations can either be placed to manage decay or cervical wear/sensitivity. The handling of data for restorations during epidemiological surveys is critical to the accurate assessment of caries prevalence. The objective of this study was to determine the relative frequency of dentists' placing root surface restorations according to their reason for placement. Data for 696 restorations were recorded from 35 dentists. Forty-five % of restorations were placed because of decay compared with 55% for cervical wear/sensitivity. There were no significant differences in proportion of placement of restoration with age of the patient or between regular and irregular attenders of different ages. Using these data a correction factor was developed for inclusion in the Root Caries Index (RCI) to make allowance for the proportion of restorations placed because of wear/sensitivity. When this correction factor was introduced into an existing data-set for root caries, the RCI was reduced for all groups. This reduction was greatest in regular attenders. When these data were analysed without making allowance for treatment effects, there was a significant difference in RCI between regular and irregular attenders. When the correction factor was applied to these data, this difference was eliminated. [source] A shear stress-based parameter for fretting fatigue crack initiationFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 7 2001C. D. Lykins The purpose of this study was to investigate the fretting fatigue crack initiation behaviour of titanium alloy, Ti,6Al,4V. Fretting contact conditions were varied by using different geometries of the fretting pad. Applied forces were also varied to obtain fretting fatigue crack initiation lives in both the low- and high-cycle fatigue regimes. Fretting fatigue specimens were examined to determine the crack location and the crack angle orientation along the contact surface. Salient features of fretting fatigue experiments were modelled and analysed with finite element analysis. Computed results of the finite element analyses were used to formulate a shear stress-based parameter to predict the fretting fatigue crack initiation life, location and orientation. Comparison of the analytical and experimental results showed that fretting fatigue crack initiation was governed by the maximum shear stress, and therefore a parameter involving the maximum shear stress range on the critical plane with the correction factor for the local mean stress or stress ratio effect was found to be effective in characterizing the fretting fatigue crack initiation behaviour in titanium alloy, Ti,6Al,4V. [source] The validation of some methods of notch fatigue analysisFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2000Taylor This paper is concerned with the testing and validation of certain methods of notch analysis which the authors have developed theoretically in earlier publications. These methods were developed for use with finite element (FE) analysis in order to predict the fatigue limits of components containing stress concentrations. In the present work we tested and compared these methods using data from standard notches taken from the literature, covering a range of notch geometries, loading types, R -ratios and materials: a total of 47 different data sets were analysed. The greatest predictive success was achieved with critical-distance methods known as the point, line and area methods: 94% of these predictions fell within 20% of the experimental fatigue limits. This was a significant improvement on previous methods of this kind, e.g. that of Klesnil and Lucas [(1980) Fatigue of Metallic Materials, Elsevier Science]. Methods based on the Smith and Miller [(1978) Int. J. Mech. Sci. 20, 201,206] concept of crack-like notches were successful in 42% of cases; they experienced difficulties dealing with very small notches, and could be improved by using an ElHaddad-type correction factor, giving 87% success. An approach known as ,crack modelling' allowed the Smith and Miller method to be used with non-standard stress concentrations, where notch geometry is ill defined; this modification, with the same short-crack correction, had 68% success. It was concluded that the critical-distance approach is more accurate and can be more easily used to analyse components of complex shape, however, the crack modelling approach is sometimes preferable because it can be used with less mesh refinement. [source] On shear-wave triplications in a multilayered transeversely isotropic medium with vertical symmetry axisGEOPHYSICAL PROSPECTING, Issue 4 2010Yuriy Roganov ABSTRACT The presence of triplications (caustics) can be a serious problem in seismic data processing and analysis. The traveltime curve becomes multi-valued and the geometrical spreading correction factor tends to zero due to energy focusing. We analyse the conditions for the qSV-wave triplications in a homogeneous transversely isotropic medium with vertical symmetry axis. The proposed technique can easily be extended to the case of horizontally layered vertical symmetry axis medium. We show that the triplications of the qSV-wave in a multilayered medium imply certain algebra. We illustrate this algebra on a two-layer vertical symmetry axis model. [source] A water heater using very high-temperature storage and variable thermal contact resistanceINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2001C. K. Jotshi Abstract This paper describes the role of thermal contact resistance in a high-temperature sensible heat storage water heater using cast iron as a storage material. An experimental set-up consisting of a cast iron cylinder and a stainless-steel tube running through its centre was fabricated and tested. The experimental data were compared with a theoretical model. It was observed that the variation in thermal contact resistance between the cast-iron blocks and the tube with temperature plays a dominant role in extracting the heat at a reasonably constant temperature. The contact resistance between two contacting surfaces was modelled as the composite of two parallel resistances: one due to the points where two surfaces contact each other and the other due to a gap between the surfaces, which is often air filled. An approximate contact resistance prediction was obtained by assuming the resistance due to the air gap modulated by a correction factor which accounts for the contacting surface area. Based on the results from the experimental set-up and theoretical modelling, a prototype storage water heater using cast-iron blocks as the storage material was designed, fabricated and tested. Copyright © 2001 John Wiley & Sons, Ltd. [source] Estimating Cardiorespiratory Fitness in Well-Functioning Older Adults: Treadmill Validation of the Long Distance Corridor WalkJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2006Eleanor M. Simonsick PhD Objectives: To determine criterion validity of the 400-m walk component of the Long Distance Corridor Walk (LDCW) and develop equations for estimating peak oxygen consumption (VO2) from 400-m time and factors intrinsic to test performance (e.g., heart rate (HR) and systolic blood pressure (SBP) response) in older adults. Design: Cross-sectional validation study. Setting: Gerontology Research Center, National Institute on Aging, Baltimore, Maryland. Participants: Healthy volunteers (56 men and 46 women) aged 60 to 91 participating in the Baltimore Longitudinal Study of Aging between August 1999 and July 2000. Measurements: The LDCW, consisting of a 2-minute walk followed immediately by a 400-m walk "done as quickly as possible" over a 20-m course was administered the day after maximal treadmill testing. HR and SBP were measured before testing and at the end of the 400-m walk. Weight, height, activity level, perceived effort, and stride length were also acquired. Results: Peak VO2 ranged from 12.2 to 31.1 mL oxygen/kg per minute, and 400-m time ranged from 2 minutes 52 seconds to 6 minutes 18 seconds. Correlation between 400-m time and peak VO2 was ,0.79. The estimating equation from linear regression included 400-m time (partial coefficient of determination (R2)=0.625), long versus short stride (partial R2=0.090), ending SBP (partial R2=0.019), and a correction factor for fast 400-m time (<240 seconds; partial R2=0.020) and explained 75.5% of the variance in peak VO2 (correlation coefficient=0.87). Conclusion: A 400-m walk performed as part of the LDCW provides a valid estimate of peak VO2 in older adults. Incorporating low-cost, safe assessments of fitness in clinical and research settings can identify early evidence of physical decline and individuals who may benefit from therapeutic interventions. [source] Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning processADVANCES IN POLYMER TECHNOLOGY, Issue 3 2004M. Golzar Abstract Online measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176,185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008 [source] Corrections for surface X-ray diffraction measurements using the Z -axis geometry: finite size effects in direct and reciprocal spaceJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2000O. Robach X-ray diffraction data have to be corrected by geometrical correction factors prior to any quantitative analysis. Here the case of grazing incidence X-ray diffraction measurements is considered, including the case of high exit angles. First, an approach taking into account the evolution of the diffracting area during an , scan is presented. From the calculation of the effective part of the sample surface that participates in the diffraction phenomena at each step of the scan, a more accurate correction factor than those commonly used is derived and the evolution of the line shape along a zero-width rod is explained. Secondly, the case of finite-width rods, under the point-like sample approximation, is considered: the influence of the partial integration, as a result of the detector in-plane acceptance, of a rod with an anisotropic in-plane shape, is studied and leads to an analytical expression for the corresponding correction factor. Finally, a full numerical simulation is presented, which provides an alternative method for correcting the experimental intensities and shows in which conditions the previous formulae are no longer valid. [source] Bond-based 3D-chiral linear indices: Theory and QSAR applications to central chirality codificationJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2008Juan A. Castillo-Garit Abstract The recently introduced non-stochastic and stochastic bond-based linear indices are been generalized to codify chemical structure information for chiral drugs, making use of a trigonometric 3D-chirality correction factor. These improved modified descriptors are applied to several well-known data sets to validate each one of them. Particularly, Cramer's steroid data set has become a benchmark for the assessment of novel quantitative structure activity relationship methods. This data set has been used by several researchers using 3D-QSAR approaches such as Comparative Molecular Field Analysis, Molecular Quantum Similarity Measures, Comparative Molecular Moment Analysis, E-state, Mapping Property Distributions of Molecular Surfaces, and so on. For that reason, it is selected by us for the sake of comparability. In addition, to evaluate the effectiveness of this novel approach in drug design we model the angiotensin-converting enzyme inhibitory activity of perindoprilate's ,-stereoisomers combinatorial library, as well as codify information related to a pharmacological property highly dependent on the molecular symmetry of a set of seven pairs of chiral N -alkylated 3-(3-hydroxyphenyl)-piperidines that bind ,-receptors. The validation of this method is achieved by comparison with earlier publications applied to the same data sets. The non-stochastic and stochastic bond-based 3D-chiral linear indices appear to provide a very interesting alternative to other more common 3D-QSAR descriptors. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] Thermal Kinetic Parameters of Thiamin in Wheat Flour at Temperatures Higher than 100°CJOURNAL OF FOOD SCIENCE, Issue 3 2005Maria Suparno ABSTRACT: Kinetic parameters for thiamin degradation were obtained using 2 high-temperature heating methods: (1) atmospheric pressure (AP) with moisture correction and (2) controlled pressure (CP). At AP conditions, 33.3% dry basis (db) moisture wheat flour with 0.35% (db) thiamin was heated in thin steel cells isothermally at 145,160, and 172°C. To obtain the moisture correction factor, a constant-moisture study was conducted at 80°C using 6 moisture contents (6.1% to 36.9%). At CP conditions, flour at 19%, 28.2%, and 33.3% (db) moisture in double-seamed cans was heated in a CP steam retort at 129°C. For the AP method, the corrected activation energy for 33.3% moisture content was 129.5 kJ/g-mol and reaction rate at 80°C was 3.48×10,4 min,1. Using the CP method, the activation energy and reaction rate were 121.0 kJ/g-mol and 9.69×10,5 min,1, respectively. Results obtained from 2 methods were not statistically different. These results illustrated that the correction method could be used as an alternative for researchers without access to controlled pressure equipment and transient heat transfer software. [source] MEASUREMENT OF FIRMNESS OF FRESH-CUT SLICED TOMATO USING PUNCTURE TESTS , STUDIES ON SAMPLE SIZE, PROBE SIZE AND DIRECTION OF PUNCTUREJOURNAL OF TEXTURE STUDIES, Issue 5 2007MILZA M. LANA ABSTRACT In order to investigate the firmness of tomato slices, two experiments were performed. In the first one, Monte Carlo simulation was used to study the variation in firmness within and between slices. Adding more slices and more measurements per slice reduced the SD, but in general, the efficiency of adding more slices was higher. In the second experiment, the firmness of tomato slices was measured by puncture test during storage, using one of three flat-tipped cylindrical probes (3.5-, 2.5- and 1.5-mm diameter) in two directions, along or perpendicular to the main axis of the fruit. Changes in firmness were studied by nonlinear regression analysis. The same model could be applied to all combinations of probe size and direction with the same correction for shear and compression. It suggests that shear and compression forces decay with storage time according to the same mechanism, irrespective of the measurement direction. PRACTICAL APPLICATIONS Methodologies for both firmness evaluation and data analysis were presented. Monte Carlo simulation was used to optimize the number of samples for firmness assays. After calculating the experimental SD from preliminary experimental results, simulations were performed with different numbers of replicates and measurements per replicate, to find an optimal experimental design where the SD is minimized. Using nonlinear regression, the effects on firmness of probe size, puncture direction in relation to the plant tissue and storage time can be analyzed simultaneously. The incorporation of a correction factor to account for differences in firmness due to probe size was proposed. The relative influence of shear (s) and compression force (c) on the observed force is estimated. Results of interest for the industry were presented, confirming previous findings that the firmness of ripened tomato slices measured by puncture analysis does not change significantly during short-term storage at low temperature. [source] CHARACTERIZATION OF AGGLOMERATION PROCESS AS A FUNCTION OF MOISTURE CONTENT USING A MODEL FOOD POWDERJOURNAL OF TEXTURE STUDIES, Issue 1 2006S. MUKHERJEE ABSTRACT A model food-powder system using rice flour of different moisture contents (11 to 22%) was used to study rheological behavior by employing a powder rheometer to obtain maximum force, energy for compression and decompression. The latter parameters were sensitive at moisture contents of ,18%. The compacted mass, obtained using a rotary punch-tableting machine, was subjected to compression testing to determine the maximum force and firmness of the compressed tablets. These two parameters increased markedly above the 17% moisture content. A significant (P , 0.01) relationship between energy for compression for powder and firmness of compacted mass indicated that an adequate integrity of the product could be achieved when a powder requires high energy for compression but low energy for decompression. A modified version of the Hausner ratio, often used to characterize the extent of compactness, was proposed that included a correction factor for loss of moisture during compaction. [source] A Calibrated, High-Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2009Simon J. Paech Paech, Simon J., John R. Mecikalski, David M. Sumner, Chandra S. Pathak, Quinlong Wu, Shafiqul Islam, and Taiye Sangoyomi, 2009. A Calibrated, High-Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration. Journal of the American Water Resources Association (JAWRA) 45(6):1328-1342. Abstract:, Estimates of incoming solar radiation (insolation) from Geostationary Operational Environmental Satellite observations have been produced for the state of Florida over a 10-year period (1995-2004). These insolation estimates were developed into well-calibrated half-hourly and daily integrated solar insolation fields over the state at 2 km resolution, in addition to a 2-week running minimum surface albedo product. Model results of the daily integrated insolation were compared with ground-based pyranometers, and as a result, the entire dataset was calibrated. This calibration was accomplished through a three-step process: (1) comparison with ground-based pyranometer measurements on clear (noncloudy) reference days, (2) correcting for a bias related to cloudiness, and (3) deriving a monthly bias correction factor. Precalibration results indicated good model performance, with a station-averaged model error of 2.2 MJ m,2/day (13%). Calibration reduced errors to 1.7 MJ m,2/day (10%), and also removed temporal-related, seasonal-related, and satellite sensor-related biases. The calibrated insolation dataset will subsequently be used by state of Florida Water Management Districts to produce statewide, 2-km resolution maps of estimated daily reference and potential evapotranspiration for water management-related activities. [source] Optimising the determination of maize endosperm vitreousness by a rapid non-destructive image analysis technique,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004Corinda Erasmus Abstract A rapid non-destructive image analysis technique was developed and optimised for the determination of maize endosperm vitreousness without the need for sample preparation. Maize kernel translucency measurements were optimised for a light system consisting of positioning whole kernels on top of round illuminated areas smaller than the projected areas of the kernels, allowing light to shine through the kernels. A correction factor to allow for constant illumination of kernels was developed to adjust for kernel size variation in relation to constant light area. The intensity of translucency in maize is linearly correlated to the percentage of kernel illumination (r = 0.99, p < 0.001). Significant correlations were found between corrected translucency values and endosperm yields determined by hand dissection. These were: translucency as a percentage of the whole kernel and vitreous endosperm (mass%), r = 0.77; translucency as a percentage of the whole kernel and opaque endosperm (mass%), (r = ,0.72); translucency as a percentage of endosperm and vitreous endosperm (mass%), r = 0.81; and translucency as a percentage of endosperm and opaque endosperm (mass%), r = ,0.77; with n = 245 in all instances. Translucency varied by 29.5% between the lowest and highest values, and vitreous endosperm (mass%) varied by 16.8% between the lowest and highest values. Correlations increased significantly after corrections for kernel thickness. A thickness increase of 1 mm in the maize will cause a decrease of 21.86% in translucency and vice versa. The method allows for large samples (at least 49 kernels min,1) to be analysed for individual vitreous and opaque endosperm contents with no interferences with kernel structure. With further development of suitable automated sampling techniques, it could become a suitable potential method for in-line quantification of maize endosperm contents. Copyright © 2004 Society of Chemical Industry [source] Accounting for co-extractable compounds (blank correction) in spectrophotometric measurement of extractable and total-bound proanthocyanidin in Leucaena sppJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2002Scott A Dalzell Abstract Methods to account for the spectral interference of co-extractable compounds (blank correction) in the spectrophotometric analysis of both extractable and bound proanthocyanidin (PA) using the proanthocyanidin (butanol/HCl) assay were evaluated. Crude extractable and bound PA sample matrices of PA-free Leucaena magnifica were used. Extractable PA blanks generated in heated 95% butanol/5% H2O reagent underestimated the optical density (absorbance) of co-extractable compounds by 24% (P,<,0.01), whereas unheated 95% butanol/5% HCl blanks, incubated at room temperature, accurately measured the absorbance of the background matrix (P,<,0.01). Current procedures that estimate bound PA concentrations using the proanthocyanidin assay produce intensely coloured background matrices. Recovery measurements from total-bound PA extracts spiked with 1071 and 2142,µg anthocyanidin per tube indicated that existing analytical procedures that do not account for the spectral interference of co-extractable compounds overestimated (P,<,0.01) bound PA concentrations by 69 and 38% respectively. An innovative technique that generated an internal correction factor for each sample, using wavelength-scanning spectrophotometry and non-linear curve-fitting computer software, was developed. This procedure recovered 100% of added anthocyanidins from bound PA matrices. © 2002 Society of Chemical Industry [source] Abundance and distribution of endangered Franciscana dolphins in Argentine waters and conservation implicationsMARINE MAMMAL SCIENCE, Issue 1 2010Enrique A. Crespo Abstract This is the first study in Argentine waters on the abundance of the threatened Franciscana dolphin, Pontoporia blainvillei. During 2003,2004 we carried out 17 aerial surveys using line transect sampling methodology. We observed 101 Franciscanas in 71 sightings. In northern areas density was estimated at 0.106 individual/km2. Density was lower in southern areas (0.055/km2) and declined with depth beyond 30-m isobaths (0.05/km2). A correction factor for submerged dolphins was applied to density and then extrapolated to the strip between the coastline and the 30-m isobath. Abundance in the northern area was estimated at 8,279 (4,904,13,960) individuals, while in the southern area it was estimated at 5,896 (1,928,17,999) individuals. Considering an annual mortality of about 500,800 individuals, about 3.5%,5.6% of the stock may be removed each year by the fishery and over the 2% recommended by the International Whaling Commission (IWC) and may not be sustainable by the population. Higher densities in coastal areas make Franciscanas more vulnerable to coastal fishing camps, which increased mortality in recent years. A remarkable finding was that while density decreases to the south, values of catch per unit effort (CPUE) increases, indicating different catchability of dolphins between areas. [source] Eigen-frequencies in thin elastic 3-D domains and Reissner,Mindlin plate modelsMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 1 2002Monique Dauge Abstract The eigen-frequencies of elastic three-dimensional thin plates are addressed and compared to the eigen-frequencies of two-dimensional Reissner,Mindlin plate models obtained by dimension reduction. The qualitative mathematical analysis is supported by quantitative numerical data obtained by the p-version finite element method. The mathematical analysis establishes an asymptotic expansion for the eigen-frequencies in power series of the thickness parameter. Such results are new for orthotropic materials and for the Reissner,Mindlin model. The 3-D and R,M asymptotics have a common first term but differ in their second terms. Numerical experiments for clamped plates show that for isotropic materials and relatively thin plates the Reissner,Mindlin eigen-frequencies provide a good approximation to the three-dimensional eigen-frequencies. However, for some anisotropic materials this is no longer the case, and relative errors of the order of 30 per cent are obtained even for relatively thin plates. Moreover, we showed that no shear correction factor is known to be optimal in the sense that it provides the best approximation of the R,M eigen-frequencies to their 3-D counterparts uniformly (for all relevant thicknesses range). Copyright © 2002 John Wiley & Sons, Ltd. [source] On some aspects of the stirring rate of planetesimal velocities by a protoplanetMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2007Adriįn Brunini ABSTRACT We discuss some aspects of the evolution of the relative velocities of a swarm of planetesimals stirred by a protoplanet. We show that the prescriptions most commonly used in semi-analytical ,oligarchic growth' models overestimate the relative velocities of planetesimals by a non-negligible factor. We discuss the probable origin of this discrepancy, proposing a correction factor that provides good agreement between these prescriptions and the results of numerical experiments. The proposed correction factor can be easily implemented in semi-analytical accretion models. [source] U-Pb Age Determination for Seven Standard Zircons using Inductively Coupled Plasma,Mass Spectrometry Coupled with Frequency Quintupled Nd-YAG (, = 213 nm) Laser Ablation System: Comparison with LA-ICP-MS Zircon Analyses with a NIST Glass Reference MaterialRESOURCE GEOLOGY, Issue 2 2008Yuji Orihashi Abstract This paper evaluates the analytical precision, accuracy and long-term reliability of the U-Pb age data obtained using inductively coupled plasma,mass spectrometry (ICP-MS) with a frequency quintupled Nd-YAG (, = 213nm) laser ablation system. The U-Pb age data for seven standard zircons of various ages, from 28 Ma to 2400 Ma (FCT, SL13, 91500, AS3, FC1, QGNG and PMA7) were obtained with an ablation pit size of 30 ,m diameter. For 207Pb/206Pb ratio measurement, the mean isotopic ratio obtained on National Institute of Standards and Technology (NIST) SRM610 over 4 months was 0.9105 ± 0.0014 (n = 280, 95% confidence), which agrees well with the published value of 0.9096. The time-profile of Pb/U ratios during single spot ablation showed no significant difference in shape from NIST SRM610 and 91500 zircon standards. These results encouraged the use of the glass standard as a calibration standard for the Pb/U ratio determination for zircons with shorter wavelength (, = 213 nm) laser ablation. But 206Pb/238U and 207Pb/235U ages obtained by this method for seven zircon standards are systematically younger than the published U-Pb ages obtained by both isotope dilution,thermal ionization mass spectrometry (ID-TIMS) and sensitive high-resolution ion-microprobe (SHRIMP). Greater discrepancies (3,4% younger ages) were found for the 206Pb/238U ages for SL13, AS3 and 91500 zircons. The origin of the differences could be heterogeneity in Pb/U ratio on SRM610 between the different disks, but a matrix effect accuracy either in the ICP ion source or in the ablation-transport processes of the sample aerosols cannot be neglected. When the 206Pb/238U (= 0.2302) newly defined in the present study is used, the measured 206Pb/238U and 207Pb/235U ages for the seven zircon standards are in good agreement with those from ID-TIMS and SHRIMP within ±2%. This suggests that SRM610 glass standard is suitable for ICP-MS with laser ablation sampling (LA-ICP-MS) zircon analysis, but it is necessary to determine the correction factor for 206Pb/238U by measuring several zircon standards in individual laboratories. [source] Variation in barometric pressure in Melbourne does not significantly affect the BTPS correction factorRESPIROLOGY, Issue 3 2004David P. JOHNS Abstract: The conventional BTPS (body temperature and pressure, saturated with water vapour) correction factor varies with ambient barometric pressure (PB) and many lung function laboratories measure PB daily. The aim was to investigate whether a fixed value for PB could replace daily measurements. PB was measured daily over a 12-month period. The highest and lowest values in Melbourne in the last century were also recorded from data published by the Bureau of Meteorology. Using these PB values, the BTPS factor was determined for a range of spirometer temperatures and compared to the BTPS factors obtained using a fixed ambient pressure of 101.3 kPa. The mean (SD) PB measured over the 12-month period was 102.2 kPa (0.64) with a range of 99.9,103.6 kPa. The level of disagreement between the BTPS factor calculated using a PB of 101.3 kPa instead of the measured value was greater at lower temperatures. Over the extremes of PB during the last century (98.0,104.3 kPa) the use of a standard pressure (101.3 kPa) produced an error in the BTPS factor of ,,0.16%. Daily variations in PB do not significantly affect the magnitude of the conventional BTPS correction factor and a fixed value, such as 101.3 kPa at sea level, can be used with little error. [source] An experimental analysis of ingestion rates in an omnivorous speciesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2008M. Stammati Abstract Food intake is difficult to estimate under natural conditions. We investigated ingestion rates of 14 different food types in 26 captive capuchin monkeys (Cebus apella). The procedure consisted in weighing a piece of food and using a two alternative choice tests to present food to the subject, alone in its cage. We recorded the food chosen and the time it took the subject to consume the food entirely. Consumption time was converted into ingestion rates (g/s) for each food type. Ingestion rates of food types significantly differed, and the difference was significantly higher among foods than among subjects. In particular, ingestion rates of the fruits were higher than those of human-processed food. Interestingly, food preferences were significantly related to energy intake rate, i.e., to the amount of energy ingested per unit of time, but not with ingestion rates or energy content alone. The energy acquired by eating different types of food cannot be calculated on the basis of the time spent eating unless a correction factor for each given food (or similar ones) is applied. Future controlled studies should provide field researchers with such corrections factors, possibly using foods collected in the wild. Am. J. Primatol. 70:510,513, 2008. © 2008 Wiley-Liss, Inc. [source] The drift factor in biased futures index pricing models: A new lookTHE JOURNAL OF FUTURES MARKETS, Issue 6 2002W. Brian Barrett The presence of bias in index futures prices has been investigated in various research studies. Redfield (11) asserted that the U.S. Dollar Index (USDX) futures contract traded on the U.S. Cotton Exchange (now the FINEX division of the New York Board of Trade) could be systematically arbitraged for nontrivial returns because it is expressed in so-called "European terms" (foreign currency units/U.S. dollar). Eytan, Harpaz, and Krull (4) (EHK) developed a theoretical factor using Brownian motion to correct for the European terms and the bias due to the USDX index being expressed as a geometric average. Harpaz, Krull, and Yagil (5) empirically tested the EHK index. They used the historical volatility to proxy the EHK volatility specification. Since 1990, it has become more commonplace to use option-implied volatility for forecasting future volatility. Therefore, we have substituted option implied volatilities into EHK's correction factor and hypothesized that the correction factor is "better" ex ante and therefore should lead to better futures model pricing. We tested this conjecture using twelve contracts from 1995 through 1997 and found that the use of implied volatility did not improve the bias correction over the use of historical volatility. Furthermore, no matter which volatility specification we used, the model futures price appeared to be mis-specified. To investigate further, we added a simple naļve , based on a modification of the adaptive expectations model. Repeating the tests using this naļve "drift" factor, it performed substantially better than the other two specifications. Our conclusion is that there may be a need to take a new look at the drift-factor specification currently in use. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:579,598, 2002 [source] One-way analysis of variance with long memory errors and its application to stock return dataAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 6 2007Jaechoul Lee Abstract Recent empirical results indicate that many financial time series, including stock volatilities, often have long-range dependencies. Comparing volatilities in stock returns is a crucial part of the risk management of stock investing. This paper proposes two test statistics for testing the equality of mean volatilities of stock returns using the analysis of variance (ANOVA) model with long memory errors. They are modified versions of the ordinary F statistic used in the ANOVA models with independently and identically distributed errors. One has a form of the ordinary F statistic multiplied by a correction factor, which reflects slowly decaying autocorrelations, that is, long-range dependence. The other is a test statistic such that the degrees of freedom of the denominator in the ordinary F test statistic is calibrated by the so-called effective sample size. Empirical sizes and powers of the proposed test statistics are examined via Monte Carlo simulation. An application to German stock returns is presented. Copyright © 2007 John Wiley & Sons, Ltd. [source] Effect of single doses of maraviroc on the QT/QTc interval in healthy subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 2008John D. Davis AIMS To assess the effect of a single dose of maraviroc on the QTc interval in healthy subjects and to evaluate the QTc interval,concentration relationship. METHODS A single-dose, placebo- and active-controlled, five-way crossover study was conducted to investigate the effects of maraviroc (100, 300, 900 mg) on QTc in healthy subjects. Moxifloxacin (400 mg) was used as the active comparator. The study was double-blind with respect to maraviroc/placebo and open label for moxifloxacin. There was a 7-day wash-out period between each dose. QT interval measurements obtained directly from the electrocardiogram (ECG) recorder were corrected for heart rate using Fridericia's correction (QTcF). A placebo run-in day was conducted before period 3, when ECGs were collected at intervals while subjects were resting or during exercise. These ECGs plus other predose ECGs were used to evaluate the QT/RR relationship for each subject to enable calculation of an individual's heart rate correction for their QT measurements (QTcI). ECGs were taken at various intervals pre- and postdose in each study period. Pharmacokinetic parameters were determined for each maraviroc dose. The end-points that were evaluated were QTcF at median time to maximum concentration (Tmax) based on the machine readings and QTcI at median Tmax based on manual over-reads of the QT/RR data. A separate analysis of variance was used for each of the pair-wise comparisons for each end-point. The relationship between QTc interval and plasma concentration was also investigated using a mixed-effects modelling approach, as implemented by the NONMEM software system. A one-stage model was employed in which the relationship between QT and RR and the effects of maraviroc plasma concentration on QT were estimated simultaneously. RESULTS The mean difference from placebo in machine-read QTcF at median Tmax for maraviroc 900 mg was 3.6 ms [90% confidence interval (CI) 1.5, 5.8]. For the active comparator, moxifloxacin, the mean difference from placebo in machine-read QTcF was 13.7 ms. The changes from placebo for each of the end-points were similar for men and women. No subjects receiving maraviroc or placebo had a QTcF ,,450 ms (men) or QTcF ,,470 ms (women), nor did any subject experience a QTcF increase ,,60 ms from baseline at any time point. Analysis based on the QTcI data obtained from the manual over-readings of the ECGs gave numerically very similar results. The QT:RR relationship was similar pre- and postdose and was not related to maraviroc concentration. The population estimate of the QT:RR correction factor was 0.324 (95% CI 0.309, 0.338). The population estimate of the slope describing the QT,concentration relationship was 0.97 ,s ml ng,1 (95% CI ,0.571, 2.48), equivalent to an increase of 0.97 ms in QT per 1000 ng maraviroc plasma concentration. Most adverse events were mild to moderate in severity. CONCLUSIONS Single doses of maraviroc, up to and including 900 mg, had no clinically relevant effect on QTcF or QTcI. At all maraviroc doses and for both end-points, the mean difference from placebo for QTc was <4 ms. There was no apparent relationship between QT interval and maraviroc plasma concentration up to 2363 ng ml,1. This conclusion held in both male and female subjects, and there was no evidence of a change in the QT/RR relationship with concentration. [source] Internationalizing the Broselow Tape: How Reliable Is Weight Estimation in Indian ChildrenACADEMIC EMERGENCY MEDICINE, Issue 5 2008Naresh Ramarajan AB Abstract Objectives:, The Broselow pediatric emergency weight estimation tape is an accurate method of estimating children's weights based on height,weight correlations and determining standardized medication dosages and equipment sizes using color-coded zones. The study objective was to determine the accuracy of the Broselow tape in the Indian pediatric population. Methods:, The authors conducted a 6-week prospective cross-sectional study of 548 children at a government pediatric hospital in Chennai, India, in three weight-based groups: <10 kg (n = 175), 10,18 kg (n = 197), and >18 kg (n = 176). Measured weight was compared to Broselow-predicted weight, and the percentage difference was calculated. Accuracy was defined as agreement on Broselow color-coded zones, as well as agreement within 10% between the measured and Broselow-predicted weights. A cross-validated correction factor was also derived. Results:, The mean percentage differences were ,2.4, ,11.3, and ,12.9% for each weight-based group. The Broselow color-coded zone agreement was 70.8% in children weighing less than 10 kg, but only 56.3% in the 10- to 18-kg group and 37.5% in the >18-kg group. Agreement within 10% was 52.6% for the <10-kg group, but only 44.7% for the 10- to 18-kg group and 33.5% for the >18-kg group. Application of a 10% weight-correction factor improved the percentages to 77.1% for the 10- to 18-kg group and 63.0% for the >18-kg group. Conclusions:, The Broselow tape overestimates weight by more than 10% in Indian children >10 kg. Weight overestimation increases the risk of medical errors due to incorrect dosing or equipment selection. Applying a 10% weight-correction factor may be advisable. [source] Bubble Size Distribution in Oil-Based Bubble ColumnsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 11 2008S.-S. Homayouni Abstract A practical population balance model was used to evaluate the bubble size distribution in a bubble column. In addition, the bubble size distribution in the bubble column was measured at different gas velocities by photography and analysis of the pictures. Four types of liquid, i.e., water and three petroleum-based liquids, were used in the experiments. The gas phase was air. It was found that the existing models in the literature are not able to satisfactorily predict the experimentally measured bubble size distribution. The model can be corrected by applying a correction factor to the energy dissipation rate. The corrected model fits the experimental bubble size distribution considerably better than the existing models. The variation of this correction factor is reported for different systems at different gas velocities. [source] | |||||||||||||||||||||||||||||||