Search results for "deviation"
showing 10 items of 367 documents
Pointwise resolutive significance of data and applications in experimental design and data treatment
1992
Abstract The concept of the resolutive significance of a point in a data set with regard to a number of addressed parameters is introduced, and two algorithms able to measure it are proposed. The algorithms are validated using simulated experiments. The sum of all the pointwise resolutive significances of a data set is also proposed as a measure of the resolution of the data set. This sum correlates well with the reciprocal of the standard deviation of the fitted parameters, indicating the precision that can be expected for each parameters. Applications in experimental design, and a method for establishing the weights in the least-quarters regression analysis are discussed.
A Model for the Description, Simulation, and Deconvolution of Skewed Chromatographic Peaks
1997
A family of models is proposed for the description of skewed chromatographic peaks, based on the modification of the standard deviation of a pure Gaussian peak, by the use of a polynomial function, h(t) = He-(1/2)([t-tR]/[s0+s1(t-tR)+s2(t-tR)2+...])2, where H and tR are the height and time at the peak maximum, respectively. The model has demonstrated a high flexibility with peaks of a wide range of asymmetry and can be used to accurately predict the profile of asymmetrical peaks, using the values of efficiency and asymmetry factor measured on experimental chromatograms. This possibility permits the simulation of chromatograms and the optimization of the separation of mixtures of compounds p…
Fast analysis of polyphenols and alkaloids in cocoa-based products by ultra-high performance liquid chromatography and Orbitrap high resolution mass …
2018
The cocoa varieties Criollo, Forastero and Trinitario, which have different organoleptic properties, quite often are mixed together in cocoa-based products. The objective of this work was to develop a rapid method for the simultaneous determination of polyphenols (n = 35) and alkaloids (n = 2) in cocoa-based products by using the high throughput advantages provided by the Q Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer (FIRMS). The proposed procedure was optimized and validated in terms of selectivity and specificity (mass accuracy 0.990), accuracy (recovery range from 89.1 to 112.4%) and precision (relative standard deviation < 10%). The method was applied to 80 cocoa-based samples…
Evaluation of beauvericin and enniatins in Italian cereal products and multicereal food by liquid chromatography coupled to triple quadrupole mass sp…
2013
In this study, 48 multicereal baby foods samples including 25 of pasta and 23 of multicereal baby foods from supermarkets of Campania region (Italy) were analysed for evaluating the presence of beauvericin (BEA) and enniatins (ENs) A, A1, B, B1 and B4. Subsequently to evaluate the risk exposure of Italian population and infant population over the consumption of pasta or multicereal baby food, was, respectively, evaluated. For the above mentioned evaluation, a method developed in our laboratory by liquid chromatography tandem mass spectrometry was used. A liquid phase dispersion procedure was optimised for the simultaneous extraction of BEA and the five ENs from multicereal baby food samples…
Influence of the porosity profile and sets of Ergun constants on the main hydrodynamic parameters in the trickle-bed reactors
2014
Abstract The Eulerian multiphase code has been applied for the comparative simulation of the experimental results obtained for varying flow rates of both fluid phases and for systems of various physicochemical properties used in the laboratory trickle-bed reactor (TBR). Therefore six different radial porosity profiles and three sets of the Ergun constants used in the relations defining the interphase momentum exchange have been implemented into the CFD code. The mean relative error of the pressure drop and of the averaged holdup as well as the standard deviation determined with respect to the experiments have been used as the criterion for the validation of the theoretical model. These valu…
Quantification of electrochromic kinetics by analysis of RGB digital video images
2018
A new, rapid, and practical procedure to obtain quantitative kinetic information of electrochromic materials is proposed. When the transition between two colors on a colored electrode surface is monitorized by digital video, the analysis of pixel color intensity (I) in sequential RGB digital images allows us to precise the half-life time (t1/2) of the color change since a maximum value of the standard deviation of the pixel intensity (σ(I)) is reached. We simulated and analyzed the evolution of standard deviation during an electrochromic transition in different circumstances (kinetic and diffusion control). As an example of application, electrochromic transitions of a thin film model, the P…
Calcifying zooplankton standing stocks and in the North Pacific from the R/V Kilo Moana cruise KM1712
2022
This dataset compiles the standing stocks (ind/m³), the integrated standing stocks (ind/m²) and the integrated CaCO3 standing stocks (mg/m²) for three groups of zooplanktonic calcifying organisms: pteropods, heteropods and foraminifers. The organisms were collected by oblique towing (Ø 0.5 m, 90 μm mesh size, SeaGear mechanical flowmeter) in the North Pacific between Hawaii and the Gulf of Alaska during the R/V Kilo Moana cruise KM1712 in August 2017. The sampling strategy was designed to capture an integrated sample of all foraminifers, pteropods and heteropods from juveniles to adults living throughout the upper water column. Pteropods and heteropods were quantified and shell diameter mea…
Severe beak deformity in Melopsittacus undulatus caused by Knemidocoptes pilae
2014
An outbreak of knemidocoptic mange caused by Knemidocoptes pilae is described in caged Australian budgerigars (Melopsittacus undulatus) in a public park in L´Eliana (Valencia, Spain). Five individuals (5 out of 70) displayed severe malformation of the beak, with the rhamphotheca, rhinotheca, and gnathotheca affected and a slight lateral deviation of the jawbone, which did not, however, impede feeding or grooming.
Physicochemical compatibility and stability of nebulizable drug admixtures containing Dornase alfa and tobramycin.
2012
The objective of this in-vitro study was to determine whether admixtures of the inhalation solutions Pulmozyme(®) (Dornase alfa) and either Bramitob(®) or Tobi(®) (both containing Tobramycin) are physicochemically compatible and to analyze the aerodynamic parameters of these admixtures. After mixing, test solutions were stored at room temperature and under ambient light conditions over a period of 24 h. Tobramycin concentrations were determined by using a fluorescence immunoassay. Stability of dornase alfa was determined by size-exclusion high performance liquid chromatography, ultraviolet spectroscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis and tentacle strong cation-exc…
QA of dynamic MLC based on EPID portal dosimetry.
2010
Abstract Purpose Dynamic delivery of intensity modulated beams (dIMRT) requires not only accurate verification of leaf positioning but also a control on the speed of motion. The latter is a parameter that has a major impact on the dose delivered to the patient. Time consumed in quality assurance (QA) procedures is an issue of relevance in any radiotherapy department. Electronic portal imaging dosimetry (EPID) can be very efficient for routine tests. The purpose of this work is to investigate the ability of our EPID for detecting small errors in leaf positioning, and to present our daily QA procedures for dIMRT based on EPID. Methods and materials A Varian 2100 CD Clinac equipped with an 80 …