2,301 research outputs found

    Pigment analysis by Raman microscopy and portable X-ray fluorescence (pXRF) of thirteenth to fourteenth century illuminations and cuttings from Bologna

    Get PDF
    Non-destructive pigment analysis by Raman microscopy (RM) and portable X-ray fluorescence (pXRF) has been carried out on some Bolognese illuminations and cuttings chosen to represent the beginnings, evolution and height of Bolognese illuminated manuscript production. Dating to the thirteenth and fourteenth centuries and held in a private collection, the study provides evidence for the pigments generally used in this period. The results, which are compared with those obtained for other north Italian artwork, show the developments in usage of artistic materials and technique. Also addressed in this study is an examination of the respective roles of RM and pXRF analysis in this area of technical art history

    Catalysis of the Michael reactions by N,N’-dimethylaminopropyl derivatised micelle templated silica: Effects of solvent and catalyst loading

    Get PDF
    A neutral amine templating route was used to prepare dimethylaminopropyl-derivatised micelle templated silicas with various loadings. The resultant materials were characterised by various techniques and were also screened as catalysts in model Michael addition reactions. Results obtained show that materials with surface areas and organic group loading as high as 800 m2g-1 and 3.4 mmol per g of silica, respectively, are obtainable. The materials show moderate to high catalytic activity as well as selectivity in a range of substrates. The activities and selectivities,however, are affected by catalyst loading and type of solvent. KEY WORDS: Catalysis of Michael reactions, N,N'-Dimethylaminopropyl-derivatised micelle templated silicas, Effect of catalyst loading, Solvent effect  Bull. Chem. Soc. Ethiop. 2003, 17(2), 219-234

    Sustainable bio-based solid phase extraction adsorbent for the determination of various types of organic compounds

    Get PDF
    © TÜBÄ°TAK. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/A sustainable, bio-based, mesoporous material, Starbon A800, was explored for use as an adsorbent in solid phase extraction (SPE). A solution containing seven nitrosamines was first used as a standard to optimise conditions for extraction efficiency with Starbon A800. After optimising conditions, 25 compounds of varying polarity (terpenes, phenolics, pesticides, PAHs, amines, and nitrosamines) were extracted with SPE using either StarbonÂź A800, C18 or Porous Graphitic Carbon (PGC) as the adsorbent, for comparison purposes. At the same time, 3 different elution solvents (heptane, dichloromethane, and ethanol) were used for each type of adsorbent. Hansen solubility parameters can be used to choose an appropriate elution solvent for the selected SPE adsorbent. The best average SPE recoveries found for the 25 various compounds were 83%, 79%, and 65% using Starbon A800, PGC, and C18 adsorbents respectively and these had dichloromethane as the elution solvent. The identification and quantification of components was carried out using UV-visible spectroscopy, two-dimensional gas chromatography (GCxGC) with time of flight/mass spectrometry (TOF/MS) or a nitrogen chemiluminescence detector (NCD). The optimized method was successfully applied to extract volatile organic compounds from red wine and tap water using Starbon A800. Starbon A800 was shown to be a promising, low-cost, green, scalable, alternative adsorbent for the extraction of various types of organic compounds of a wide range of polarities using SPE.Peer reviewe

    The importance of information on relatives for the prediction of genomic breeding values and the implications for the makeup of reference data sets in livestock breeding schemes.

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The theory of genomic selection is based on the prediction of the effects of genetic markers in linkage disequilibrium with quantitative trait loci. However, genomic selection also relies on relationships between individuals to accurately predict genetic value. This study aimed to examine the importance of information on relatives versus that of unrelated or more distantly related individuals on the estimation of genomic breeding values.</p> <p>Methods</p> <p>Simulated and real data were used to examine the effects of various degrees of relationship on the accuracy of genomic selection. Genomic Best Linear Unbiased Prediction (gBLUP) was compared to two pedigree based BLUP methods, one with a shallow one generation pedigree and the other with a deep ten generation pedigree. The accuracy of estimated breeding values for different groups of selection candidates that had varying degrees of relationships to a reference data set of 1750 animals was investigated.</p> <p>Results</p> <p>The gBLUP method predicted breeding values more accurately than BLUP. The most accurate breeding values were estimated using gBLUP for closely related animals. Similarly, the pedigree based BLUP methods were also accurate for closely related animals, however when the pedigree based BLUP methods were used to predict unrelated animals, the accuracy was close to zero. In contrast, gBLUP breeding values, for animals that had no pedigree relationship with animals in the reference data set, allowed substantial accuracy.</p> <p>Conclusions</p> <p>An animal's relationship to the reference data set is an important factor for the accuracy of genomic predictions. Animals that share a close relationship to the reference data set had the highest accuracy from genomic predictions. However a baseline accuracy that is driven by the reference data set size and the overall population effective population size enables gBLUP to estimate a breeding value for unrelated animals within a population (breed), using information previously ignored by pedigree based BLUP methods.</p

    Gauge dependence of effective action and renormalization group functions in effective gauge theories

    Get PDF
    The Caswell-Wilczek analysis on the gauge dependence of the effective action and the renormalization group functions in Yang-Mills theories is generalized to generic, possibly power counting non renormalizable gauge theories. It is shown that the physical coupling constants of the classical theory can be redefined by gauge parameter dependent contributions of higher orders in ℏ\hbar in such a way that the effective action depends trivially on the gauge parameters, while suitably defined physical beta functions do not depend on those parameters.Comment: 13 pages Latex file, additional comments in section

    First principles calculation of uniaxial magnetic anisotropy and magnetostriction in strained CMR films

    Full text link
    We performed first - principles relativistic full-potential linearized augmented plane wave calculations for strained tetragonal ferromagnetic La(Ba)MnO3_3 with an assumed experimental structure of thin strained tetragonal La0.67_{0.67}Ca0.33_{0.33}MnO3_3 (LCMO) films grown on SrTiO3_3[001] and LaAlO3_3[001] substrates. The calculated uniaxial magnetic anisotropy energy (MAE) values, are in good quantitative agreement with experiment for LCMO films on SrTiO3_3 substrate. We also analyze the applicability of linear magnetoelastic theory for describing the stain dependence of MAE, and estimate magnetostriction coefficient λ001\lambda_{001}.Comment: Talk given at APS99 Meeting, Atlanta, 199

    Photo-Identification Methods Reveal Seasonal and Long-Term Site-Fidelity of Risso’s Dolphins (Grampus griseus) in Shallow Waters (Cardigan Bay, Wales)

    Get PDF
    A photo-identification study on Risso’s dolphins was carried out off Bardsey Island in Wales (July to September, 1997-2007). Their local abundance was estimated using two different analytical techniques: 1) mark-recapture of well-marked dolphins using a “closed-population” model; and 2) a census technique based on the total number of iden-tified individual dolphins sighted over the study period. The mark-recapture estimates of 121 (left sides; 64 - 178, 95% CI; CV 0.24) and 145 dolphins (right sides; 78 - 213, 95% CI; CV 0.24) closely matched the census technique estimates (population size of 90 - 151). It was found that the dolphins showed a degree of long-term and seasonal site-fidelity. A first long-distance match was made for Risso’s dolphins (319 km) between Bardsey Island and Cornwall, confirming they can be wide-ranging animals. This study demonstrates that the combination of systematic and opportunistic photo-ID studies has complementary value as a population assessment tool in generating the first local abundance esti-mate for Risso’s dolphins in UK waters. From the conservation perspective, these studies confirm the regular presence of Risso’s dolphins in these waters and the presence of calves shows breeding. Bardsey Island may be part of a network of localities that are important habitats to this species where it may take advantage of prey abundance in shallow waters. As such, results of this study may provide assistance to include the Risso’s dolphin in future regional conservation strategies including the envisaged marine protected areas

    A Detailed Monte-Carlo Simulation for the Belle TOF System

    Get PDF
    We have developed a detailed Monte Carlo simulation program for the Belle TOF system. Based on GEANT simulation, it takes account of all physics processes in the TOF scintillation counters and readout electronics. The simulation reproduces very well the performance of the Belle TOF system, including the dE/dx response, the time walk effect, the time resolution, and the hit efficiency due to beam background. In this report, we will describe the Belle TOF simulation program in detail.Comment: To be submitted to NI
    • 

    corecore