Search results for "composition"

showing 10 items of 2675 documents

Food and Environment: Trace Element Content of Hen Eggs from Different Housing Types

2013

AbstractEleven trace elements (Ba, Cu, Fe, Mn, Ni, Pb, Rb, Se, Sr, V, Zn) were quantitatively determined in hen egg samples collected from different poultry housing types (large-scale poultry farms, organic farms and domestic farms) over the territory of Latvia. Samples were wet digested and quantitatively analysed by total reflection X-ray fluorescence spectrometry (TXRF). The accuracy of analytical method was verified with analysis of certified reference material NCS ZC73017 (GSB-10)-Apple. The most variable range of concentrations and the highest content of elements were determined for hen egg samples derived from organic farms, while egg samples from domestic farms and poultry farms mos…

Trace elementsbusiness.industryEggsTrace elementFluorescence spectrometrychemistry.chemical_elementPoultry farmingLatviaEnvironmental impactGeneral EnergyAnimal scienceCertified reference materialsGeographychemistryEnvironmental chemistryOrganic farmingTXRFFood compositionQuantitative analysisbusinessSeleniumAPCBEE Procedia
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Comparison of the volatile oils ofHypericum scabrum L. andHypericum perforatum L. from Turkey

1997

The composition of the volatile oils obtained from the aerial parts of Hypericum scabrum L. and H. perforatum L. was analysed by GC and GC‐MS. While the oil of H. scabrum L. contained a-pinene (71.6%), b-caryophyllene (4.8%), myrcene (3.8%), cadalene (3.4%) and b-pinene (2.9%), the oil of H. perforatum L. contained a-pinene (61.7%), 3-carene (7.5%), b-caryophyllene (5.5%), myrcene (3.6%), cadalene (3.2%) and other components. Twenty-nine and 27 terpenoid compounds have been identified in the volatile oils of H. scabrum L. and H. perforatum L., respectively. #1997 by John Wiley & Sons, Ltd.

Traditional medicineChemistryHypericum perforatumGeneral Chemistry?-pinene; GC-MS; Guttiferae; Hypericum perforatum L; Hypericum scabrum L; Volatile oil compositionTerpenoidchemistry.chemical_compoundMyrceneBotanyGas chromatographyHypericum scabrumGas chromatography–mass spectrometryCadaleneFood ScienceFlavour and Fragrance Journal
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Null Space Based Image Recognition Using Incremental Eigendecomposition

2011

An incremental approach to the discriminative common vector (DCV) method for image recognition is considered. Discriminative projections are tackled in the particular context in which new training data becomes available and learned subspaces may need continuous updating. Starting from incremental eigendecomposition of scatter matrices, an efficient updating rule based on projections and orthogonalization is given. The corresponding algorithm has been empirically assessed and compared to its batch counterpart. The same good properties and performance results of the original method are kept but with a dramatic decrease in the computation needed.

Training setbusiness.industryComputationContext (language use)Pattern recognitionRule-based systemLinear subspaceDiscriminative modelComputer visionArtificial intelligencebusinessOrthogonalizationEigendecomposition of a matrixMathematics
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FP749The effect of short daily home hemodialysis with low-flow, lactate-buffered dialysate on nutritional status and body composition

2019

TransplantationDialysis solutionsAnimal scienceFlow (mathematics)Nephrologybusiness.industryHome hemodialysisMedicineComposition (visual arts)Nutritional statusbusinessNephrology Dialysis Transplantation
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Optimal Tree Decompositions Revisited: A Simpler Linear-Time FPT Algorithm

2020

In 1996, Bodlaender showed the celebrated result that an optimal tree decomposition of a graph of bounded treewidth can be found in linear time. The algorithm is based on an algorithm of Bodlaender and Kloks that computes an optimal tree decomposition given a non-optimal tree decomposition of bounded width. Both algorithms, in particular the second, are hardly accessible. We present the second algorithm in a much simpler way in this paper and refer to an extended version for the first. In our description of the second algorithm, we start by explaining how all tree decompositions of subtrees defined by the nodes of the given tree decomposition can be enumerated. We group tree decompositions …

TreewidthTree (data structure)Bounded functionGraph (abstract data type)Constant (mathematics)Equivalence classTree decompositionAlgorithmTime complexityMathematics
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The preparation of (14C) and [3H] labelled benzene oxide

1977

Benzene oxide -[U-14C] was prepared from benzene -(U-14C) by modifications of methods described for the inactive compound. Benzene oxide-[3.6–3H] was prepared by decomposition of 3.6-bis-trimethylsilyl-1,4-cyclohexadiene with tritiated water. bromination of the 1,4-cyclohexadiene-[3,6-3H] so obtained. epoxidation and dehydrobromination. With the latter method benzene oxide-[3,6–3H] can be prepared at a much lower cost and higher specific activity than benzene oxide-[U-14C].

Tritiated waterOrganic ChemistryInorganic chemistryOxideHalogenationBiochemistryDecompositionAnalytical Chemistrychemistry.chemical_compoundchemistryDrug DiscoveryOrganic chemistryRadiology Nuclear Medicine and imagingCarbon-14Specific activityTritiumBenzeneSpectroscopyJournal of Labelled Compounds and Radiopharmaceuticals
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Climatology of the average water-soluble volume fraction of atmospheric aerosol

2007

The average water-soluble volume fraction of atmospheric aerosol particles was inferred from measurements at three different locations across Central Europe. Together with a comprehensive literature review these data sets are classified into four aerosol types. The classified data are parameterized as a function of particle size using a logarithmic normal distribution function, which seems most appropriate to represent the hygroscopicity maximum in the accumulation size range. This parameterization can be used as a simplified input parameter for various model calculations. In addition, a summary on water-soluble volume fractions and hygroscopic growth factors is presented along with a short…

TroposphereAtmospheric ScienceVolume (thermodynamics)ClimatologyVolume fractionParticle-size distributionRange (statistics)Environmental scienceParticle sizeChemical compositionAerosolAtmospheric Research
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The dynamics of tropospheric aerosols

1966

After a brief review of the present knowledge of the Stratospheric sulfate layer, several possible mechanisms of formation are discussed in detail. A direct transport of low tropospheric particles into the stratosphere by convective clouds penetrating the tropopause is not very likely because these penetrations are not high enough and because of the chemical composition of the stratospheric particles. DOI: 10.1111/j.2153-3490.1966.tb00287.x

TroposphereConvectionchemistry.chemical_compoundchemistryClimatologyEnvironmental scienceGeneral MedicineTropopauseSulfateAtmospheric sciencesChemical compositionStratosphereTellus
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Size Matters More Than Chemistry for Cloud-Nucleating Ability of Aerosol Particles

2006

Size-resolved cloud condensation nuclei (CCN) spectra measured for various aerosol types at a non-urban site in Germany showed that CCN concentrations are mainly determined by the aerosol number size distribution. Distinct variations of CCN activation with particle chemical composition were observed but played a secondary role. When the temporal variation of chemical effects on CCN activation is neglected, variation in the size distribution alone explains 84 to 96% of the variation in CCN concentrations. Understanding that particles' ability to act as CCN is largely controlled by aerosol size rather than composition greatly facilitates the treatment of aerosol effects on cloud physics in re…

TroposphereMultidisciplinaryMeteorologyChemistryCloud physicsCloud condensation nucleiParticleCCNCKöhler theoryAtmospheric sciencescomplex mixturesChemical compositionAerosolScience
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Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

2011

Abstract Tunisia has numerous thermo-mineral springs. Previous studies have shown that their chemical composition and occurrence are strongly influenced by the regional geology. However little work has been done so far to study the isotopic composition of volatiles associated with these geothermal manifestations. Here, we report on the results of an extensive survey of both natural hot springs and production wells across Tunisia, aimed at investigating the spatial distribution of thermal fluids' geochemical characteristics and He–C isotopic composition. The chemistry of the analyzed samples highlights the heterogeneity of the water mineralization processes in Tunisia, as a consequence of th…

Tunisia010504 meteorology & atmospheric sciencesEarth scienceGeochemistryAquiferengineering.material010502 geochemistry & geophysics01 natural sciencesMantle (geology)Geochemistry and PetrologyTunisia; Helium isotopes; Carbon isotopes; Geothermal fluids; Groundwaters; Thermal springs[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environmentGroundwaterChemical compositionGeothermal gradientComputingMilieux_MISCELLANEOUS0105 earth and related environmental sciences[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmospheregeographygeography.geographical_feature_categoryRiftCarbon isotopeThermal springsGeologyHelium isotopeSettore GEO/08 - Geochimica E Vulcanologia13. Climate actionIsotopes of carbonMagmatismengineeringHaliteGeothermal fluidGeologyChemical Geology
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