66 research outputs found

    Late Bronze Age Hoard studied by PIXE

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    The hoards of metallic objects belonging to the Late European Bronze Age can be interpreted differently depending on the type, number and composition of the artefacts. PIXE analysis has been performed in nine items from the Hoard of Freixanda in Portugal comprising 4 socket axes, a palstave axe, a ring, a chisel, a dagger, and a casting debris. Besides the composition of the main matrix elements, that is Cu and Sn, the amount of trace elements of interest like, As, Pb, Ni and Ag has been determined using this ion beam technique. The high tin content alloy and the high purity of the metals from the Freixanda hoard are characteristic of the Portuguese and Spanish Late Bronze Age metallurgy, supporting the idea of a regional production

    Elemental characterization of PM10, PM2.5 and PM1 in the town of Genoa (Italy)

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    The particulate matter (PM) concentration and composition, the PM10, PM2.5, PM1 fractions, were studied in the urban area of Genoa, a coastal town in the northwest of Italy. Two instruments, the continuous monitor TEOM and the sequential sampler PARTISOL, were operated almost continuously on the same site from July 2001 to September 2004. Samples collected by PARTISOL were weighted to obtain PM concentration and then analysed by PIXE (particle induced X-ray emission) and by ED-XRF (energy dispersion X-ray fluorescence), obtaining concentrations for elements from Na to Pb. Some of the filters used in the TEOM microbalance were analysed by ED-XRF to calculate Pb concentration values averaged over 7\u201330 d periods

    Precise Measurement of Sigma Beam Asymmetry for Positive Pion Photoproduction on the Proton from 800 to 1500 Mev

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    The Sigma beam asymmetry for positive pion photoproduction on the proton has been measured over an angular range of 40-170 deg at photon energies from 0.8 to 1.5 GeV. The resulting data set includes 237 accurate points, 136 of these belonging to an almost unexplored domain above 1.05 GeV. Data of such high precision provide severe constraints for partial wave analyses. The influence of this experiment on the GW multipole analysis is demonstrated. Significant changes are found in multipoles connected to the S31(1620) and P13(1720) resonances. Comparisons using the MAID analysis are also presented.Comment: 11 pages, 4 eps figures. to be published in Physics Letters

    Bremsstrahlung Suppression due to the LPM and Dielectric Effects in a Variety of Materials

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    The cross section for bremsstrahlung from highly relativistic particles is suppressed due to interference caused by multiple scattering in dense media, and due to photon interactions with the electrons in all materials. We present here a detailed study of bremsstrahlung production of 200 keV to 500 MeV photons from 8 and 25 GeV electrons traversing a variety of target materials. For most targets, we observe the expected suppressions to a good accuracy. We observe that finite thickness effects are important for thin targets.Comment: 52 pages, 13 figures (incorporated in the revtex LaTeX file

    Effects of Topically Administered Neuroprotective Drugs in Early Stages of Diabetic Retinopathy:Results of the EUROCONDOR Clinical Trial

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    The primary objective of this study was to assess whether the topical administration of two neuroprotective drugs (brimonidine and somatostatin) could prevent or arrest retinal neurodysfunction in patients with type 2 diabetes. For this purpose, adults aged between 45 and 75 years with a diabetes duration ≥5 years and an Early Treatment of Diabetic Retinopathy Study (ETDRS) level of ≤35 were randomly assigned to one of three arms: placebo, somatostatin, or brimonidine. The primary outcome was the change in implicit time (IT) assessed by multifocal electroretinography between baseline and at the end of follow-up (96 weeks). There were 449 eligible patients allocated to brimonidine (n = 152), somatostatin (n = 145), or placebo (n = 152). When the primary end point was evaluated in the whole population, we did not find any neuroprotective effect of brimonidine or somatostatin. However, in the subset of patients (34.7%) with preexisting retinal neurodysfunction, IT worsened in the placebo group (P < 0.001) but remained unchanged in the brimonidine and somatostatin groups. In conclusion, the topical administration of the selected neuroprotective agents appears useful in preventing the worsening of preexisting retinal neurodysfunction. This finding points to screening retinal neurodysfunction as a critical issue to identify a subset of patients in whom neuroprotective treatment might be of benefit

    L’esperienza teatrale nella formazione dei futuri mediatori linguistici e culturali

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    Il volume raccoglie e sistematizza l’esperienza del teatro universitario in lingua straniera presso la Scuola Superiore di Lingue Moderne per Interpreti e Traduttori dell’Università di Bologna, sede di Forlì. Una metodologia innovativa che integra la complessa formazione dei mediatori linguistici e culturali attraverso lo sviluppo di capacità quali comprensione empatica, flessibilità cognitiva, sensibilità (inter)culturale e creatività. Le riflessioni teoriche esposte nei saggi selezionati nascono dalla pratica pluriennale vissuta nell’aula-palcoscenico, creando un dialogo interdisciplinare che consente al lettore di ripercorrere le emozioni e i viaggi formativi racchiusi nell’archivio della memoria di una Facoltà-Babele

    Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

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    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL) (http://www-nds.iaea.org/ibandl) by members of the IBA community by 2011, however a preliminary survey of this body of unevaluated experimental data has revealed numerous discrepancies beyond the uncertainty limits reported by the authors. Using the resources and coordination provided by the IAEA, a concerted effort to improve the situation was made within the Coordinated Research Project on the Development of a Reference Database for PIGE spectroscopy, from 2011 to 2015. The aim of the CRP was to create a data library for Ion Beam Analysis that contains reliable and usable data on charged particle γ-ray emission cross sections that would be made freely available to the user community. As the CRP has reached its completion, we shall present its main achievements, including the results of nuclear cross-section evaluations and the development of a computer code that will become available to the public allowing for the implementation of a standardless PIGE technique. © 2015 Elsevier B.V. All rights reserved

    Amorphous glass fragments from archaeological surface surveys: Potential chronological use of ion beam and isotopic analytical characterization

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    Analytical techniques have been used to implement the archaeological information from surface surveys. We have shown that the compositional comparison of amorphous samples, e.g. glass, can provide important chronological information when compared with findings from other sites. A group of 61 glass fragments, recovered from an archaeological surface survey at the site of the Roman city of Duratón (1st to 3rd century AD), near Segovia, Spain, have been analysed by combined Particle Induced X-ray/Gamma-ray Emission (PIXE-PIGE) techniques and by isotope dilution mass spectrometry. Four groups of objects were identified. The largest group by far, corresponds to the typical sodium-rich natron-made Roman glass. Compared with data reported in previous studies, including a few on the Iberian Peninsula, the composition of Duratón natron glass is similar to that of the widespread Roman 1st–3rd century AD glasses. The glasses of the nearby Patones, six of which have been analysed in this study, belong, on the contrary, to the so-called HIMT glass. This is compatible with the soda-lime-silica glass pattern observed in the Western Mediterranean. HIMT glass is dominant in this area from the 4th century onward. HIMT glass products are much easier to make and less expensive. Strontium and neodimium isotope analysis confirms the compositional proximity of the Duratón glasses to three groups of 1st–3rd century samples from Barcino, Lyon and the Iulia Felix wreck and point to a production of the glass in the Eastern Mediterranean. Pliny the Elder in his Naturalis Historia had specifically mentioned the glass production of Hispania and Gallia, which should hopefully be confirmed by the findings in the corresponding regional sites. This is the case for Gallia but not yet for the Iberian Peninsula, where few Roman glass analyses have been completed
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