Search results for "square"
showing 10 items of 1317 documents
Influence of different biomaterials on the viability of Aggregatibacter actinomycetemcomitans
2011
Abstract Objectives The aim of the present in vitro study was to evaluate the effects of different biomaterials used for regenerative periodontal surgery on the growth of the periodontopathogen Aggregatibacter actinomycetemcomitans . Methods Three commercially available biomaterials of synthetic origin (hydroxyapatite/beta-tricalcium phosphate, nanostructured hydroxyapatite paste, oily calcium hydroxide suspension), a bovine-derived xenograft as well as an enamel matrix derivative (EMD) were added in different concentrations to calibrated suspensions of A. actinomycetemcomitans ATCC 43718/33384 (serotype b/c). Equal aliquots (0.1 ml) for the viability assay were taken after 5 min, 1 h, 3 h,…
Multivariate quality control studies applied to Ca(II) and Mg(II) determination by a portable method
1998
Made available in DSpace on 2022-04-28T19:53:14Z (GMT). No. of bitstreams: 0 Previous issue date: 1998-01-01 A portable or field test method for simultaneous spectrophotometric determination of calcium and magnesium in water using multivariate partial least squares (PLS) calibration methods is proposed. The method is based on the reaction between the analytes and methylthymol blue at pH 11. The spectral information was used as the X-block and the Ca(II) and Mg(II) concentrations obtained by a reference technique (ICP-AES) were used as the Y-block. Two series of analyses were performed, with a month's difference between them. The first series was used as the calibration set and the second on…
Calibration transfer in chemiluminescence analysis
2001
Abstract Direct standardization (DS) and piecewise direct standardization (PDS) methods are applied to multivariate standardization of chemiluminescence signals using PLS model as the calibration model. The linear concentration interval of the chemiluminescence determination was determined. This interval was located using univariate robust calibration by least median of squares (LMS) method. The linear calibration model was corroborated by conventional least-squares method. The standardization subset and window size were optimized by means of the prediction residual error sum of squares. Several instrumental sources of variability have been studied: the detection cell, instrument, batch ver…
Simulation studies of gas-liquid transitions in two dimensions via a subsystem-block-density distribution analysis
1993
The finite-size scaling analysis of the density distribution function of subsystems of a system studied at constant total density is studied by a comparative investigation of two models: (i) the nearest-neighbor lattice gas model on the square lattice, choosing a total lattice size of 64×64 sites. (ii) The two-dimensional off-lattice Lennard-Jones system (truncated at a distance of 2.5 σ, σ being the range parameter of the interaction) withN=4096 particles, applying the NVT ensemble. In both models, the density distribution functionPL(ρ) is obtained forL×L subsystems for a wide range of temperaturesT, subblock linear dimensionsL and average densities . Particular attention is paid to the qu…
Finite-size scaling in a microcanonical ensemble
1988
The finite-size scaling technique is extended to a microcanonical ensemble. As an application, equilibrium magnetic properties of anL×L square lattice Ising model are computed using the microcanonical ensemble simulation technique of Creutz, and the results are analyzed using the microcanonical ensemble finite-size scaling. The computations were done on the multitransputer system of the Condensed Matter Theory Group at the University of Mainz.
A global Canopy Water Content product from AVHRR/Metop
2020
Abstract Spatially and temporally explicit canopy water content (CWC) data are important for monitoring vegetation status, and constitute essential information for studying ecosystem-climate interactions. Despite many efforts there is currently no operational CWC product available to users. In the context of the Satellite Application Facility for Land Surface Analysis (LSA-SAF), we have developed an algorithm to produce a global dataset of CWC based on data from the Advanced Very High Resolution Radiometer (AVHRR) sensor on board Meteorological–Operational (MetOp) satellites forming the EUMETSAT Polar System (EPS). CWC reflects the water conditions at the leaf level and information related …
Canopy chlorophyll content and LAI estimation from Sentine1-2: Vegetation indices and Sentine1-2 Leve1-2A automatic products comparison
2019
The aim of this work is to analyze different methodologies for the estimation of leaf area index (LAI) and canopy chlorophyll content (CCC), using the Sentine1-2 satellite. LAI and CCC are biophysical parameters indicator of crop health state and fundamental in the productivity prediction. The purpose is to define the most optimal LAI and CCC estimation method for operational use in the monitoring of agricultural areas. Moreover, the CCC and LAI automatic products obtained directly through the Sentinel Application Platform Software (SNAP) biophysical processor and Sentine1-2 images by means of an artificial neural network (ANN) are validated. On the other hand, common vegetation indices use…
Prototyping of Land-SAF leaf area index algorithm with VEGETATION and MODIS data over Europe
2009
Abstract The Satellite Application Facility on Land Surface Analysis (Land-SAF) aims to provide land surface variables for the meteorological and environmental science communities from EUMETSAT satellites. This study assesses the performance of a simplified (i.e. random distribution of vegetation is assumed) version of the Land-SAF algorithm for the estimation of Leaf Area Index (LAI) when prototyped with VEGETATION (processed in CYCLOPES program) and MODIS reflectances. The prototype estimates of LAI are evaluated both by comparison with validated CYCLOPES and MODIS LAI products derived from the same sensors and directly through comparison with ground-based estimates. Emphasis is given on …
Evaluation of nutritional parameters in infant formulas and powdered milk by Raman spectroscopy
2007
It has been made a critical evaluation of the application of near infrared Fourier transform-Raman spectroscopy for the simultaneous determination of the most important nutritional parameters such as energetic value, carbohydrate, protein and fat contents of infant formula and powdered milk samples based on the use of partial least squares (PLS) regression analysis. A highly heterogeneous population of 23 samples, covering a wide range of infant food formula and powdered milk, were obtained from the Spanish market. Raman spectra, obtained by excitation with a Nd:YAG laser at 1064 nm, show no disturbing fluorescence effects; therefore sample spectra can be recorded without any previous prepa…
Renal function and carotid atherosclerosis in adults with no known kidney disease
2017
Abstract Background and aims A high prevalence of atherosclerotic lesions characterizes patients with chronic kidney disease, though there is little data on the relationship between kidney function and atherosclerotic changes in the healthy population or in people with no known renal impairment. The aim of our study was to analyze, in a comprehensive general population with no known kidney disease, the relationship between renal function and subclinical carotid atherosclerotic damage. Methods and results A general real-life population of 611 participants (233 males and 378 females; age ≥18 years) with no known kidney failure was selected for the study. The glomerular filtration rate (GFR) w…