1,721,141 research outputs found
Metrological Certification Measurements of Stable Isotope Amount Ratios of Xenon and Krypton. AContribution to Investigate the Feasibility of Using Noble Gas Isotope Amount Ratio Measurements as a Method to Identify Reprocessing Activities
No full textAbstract not availableJRC.D - Institute for Reference Materials and Measurements (Geel
CCQM-P39.1: As, Hg, Pb, Se and Methylmercury in Salmon
No full textCCQM-P39.1 was organized as a follow-up pilot study in parallel to the key comparison CCQM-K43 after the previous pilot study on tuna fish. CCQM-P39.1 was an activity of the Inorganic Analysis Working Group (IAWG) of CCQM and was coordinated by the Joint Research Centre–Institute for Reference Materials and Measurements (IRMM, Geel, Belgium) of the European Commission (EC). In CCQM-P39.1 the amount contents of As, Hg, Pb, Se and methylmercury (CH3Hg) in salmon (muscle and skin) were the measurands under investigation. Besides the national metrology institutes (NMIs) also non-IAWG members, expert laboratories for mercury and methylmercury measurements, were invited to participate in this pilot study. Results were reported by six IAWG members and six expert laboratories. During the CCQM-IAWG autumn meeting in Berlin, October 2005, it was agreed that in CCQM-K43 the KCRV is calculated as the mixture model median (MM-median) of all reported results. Therefore in CCQM-P39.1 the reported results are presented graphically with the KCRV from CCQM-K43. The reported results of the IAWG members fall within a range of ±4% for arsenic and lead relative to the CCQM-K43 KCRV. For mercury, the spread was ±2%, but one IAWG member reported a very large uncertainty on the measurement result. For selenium the spread of IAGW members is ±2% deviation from the CCQM-K43 KCRV. Including the reported results from the invited expert laboratories, the spread of results increased for arsenic, lead and mercury to ±8%. The reported results including the experts fall within a range of ±20% for selenium and ±30% for methylmercury.The methods applied were isotope dilution mass spectrometry (IDMS) using sector field or quadrupole inductively coupled plasma-mass spectrometry (ICP-MS), external calibration or standard addition using ICP-MS, atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), atomic emission detection (AED) and electron capture detection (ECD). Instrumental neutron activation analysis (INAA) and k0-neutron activation analysis (k0-NAA) were also used as analytical techniques. Each of the five analytes under investigation was measured with at least two of these analytical techniques.IAEA reported two results for arsenic and lead. They were measured with ICP-MS and AAS, respectively. JSI reported two results for mercury, measured with NAA and AAS, and furthermore two results for methylmercury measured with GC-ECD and GC-CV-AFS.This report presents the participants' results in CCQM-P39.1 for all analytes under investigation. In Annex 1, the results are displayed with the CCQM-K43 KCRV. In Annex 2, the different approaches for methlymercury measurements are presented in more detail. In Annex 3, the questionnaire data are presented. Annex 4 compiles all the CCQM-P39.1 information documents.The key comparison CCQM-K43 was carried out in parallel to this pilot study for the same measurands in the same salmon material. Participation was meant for IAWG members, to support their CMCs in Appendix C.JRC.D.4 - Isotope measurement
Technical convergence of nuclear safeguards, nuclear forensics and nuclear security
No full textFrom the first implementation of safeguards agreements, measurements of nuclear material have formed the backbone of verification measures. The introduction of strengthened safeguards and the ratification of additional protocols (INFCIRC 540) led to the need for more investigative analytical measurements, similar to those implemented for the analysis of nuclear material intercepted from illicit trafficking. The requirement of nuclear forensics, to disclose additional information inherent to nuclear material, triggered the transfer of analytical techniques from the environmental area, from materials science and from the geological and cosmological areas to the safeguards community. This transfer of expertise significantly contributed to the identification of the sources of nuclear materials and the industrial processes to which they have been exposed.
The physical security of nuclear material is the responsibility of the State that owns the material. However, with increasing concern over non-State actors, it is important for the wider community to work in cooperation with States to which intercepted nuclear materials might be attributed. During the ESARDA annual meeting 2010, the ESARDA Working Group Techniques and Standards for Destructive Analysis (WG DA) adopted a new Objective in its Action Plan 2010-2012: to emphasise the technical convergence of nuclear safeguards, nuclear forensics and nuclear security by looking at available and new methodologies that serve all three purposes. The WG DA organised dedicated workshops on advancements and applicability of analytical techniques to read signatures in nuclear material and environmental samples, with participation beyond the safeguards community. The aim was to bring together experts from safeguards, nuclear forensics, earth sciences, and particularly from industry. Most recently, immediately prior to this symposium, the ESARDA WG DA held a dedicated workshop on direct analysis of solid samples using LA-ICP-MS, hosted by the HAEA. Furthermore the WG DA interacts with the WG NA/NT (Novel Technologies / Novel Approaches) to evaluate synergies.
The WG DA contributed to the revision of the International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials (ITVs) and a Workshop on Uncertainties in Nuclear Measurements is scheduled for end of this year. These contributions provide operators and inspection authorities with important information on the capabilities and expected performance of analytical techniques.
The WG DA has developed DA and forensics modules for training and education that are regularly presented at the ESARDA academic course on Nuclear Safeguards and Non-Proliferation and the BNEN advanced course on safeguards, which are recognised by the European Nuclear Higher Education Network. Additional courses in France and Sweden are scheduled for this year. Dedicated training courses in the nuclear forensics area are offered at the Institute for Transuranium Elements. Moreover, a "European Nuclear Security Training Centre" is being established at the ITU, with support of DG HOME. The EUSECTRA will offer a broad spectrum of training courses including detection of and response to nuclear security incidents and nuclear forensics. Within the WG DA, ESARDA is currently keeping abreast of methodologies applicable in the fields of nuclear safeguards, security and forensics.JRC.D.2 - Standards for Innovation and sustainable Developmen
CCQM-K43. As, Hg, Pb, Se and Methylmercury in Salmon. Final Report
No full textCCQM-K43 was organised as a follow-up key comparison to the previous pilot study on tuna fish. CCQM-K43 was an activity of the Inorganic Analysis Working Group (IAWG) of CCQM and was coordinated by the Joint Research Centre, Institute for Reference Materials and Measurements (IRMM, Geel, Belgium) of the European Commission (EC). In CCQM-K43 the amount contents of As, Hg? Pb, Se and methulmercury (CH3Hg) in salmon (muscle and skin) were the measurands under investigation. Results were reported by 12 NMIs. During the CCQM-IAWG autumn meeting in Berlin, October 2005, it was agreed that in CCQM-K43 the KCRV is calculated as the mixture model median (MM-median) of all reported results. The reported results of the NMIs fall within a range of plus minus 5% for arsenic and of plus minus 2% for lead and mercury relative to the KCRV. For selenium the spread of all laboratories but one is plus minus 8%. Also, for methylmercury 4 of the 5 participating NMIs reported results within 4% deviation from the KCRV. The methods applied were isotope dilution mass spectrometry (IDMS) using sector field or quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) or thermal ionisation mass spectrometry (TIMS), external calibration using ICP-MS or atomic absorption spectrometry (AAS). Instrumental neutron activation analysis (INAA) and K0-neutron activation analysis (K0-NAA) were also used as analytical techniques. This report presents the participants' results in CCQM-K43 for all analytes under investigation. In Annex 1, the results with the KCRV, the equivalence statements and the results sorted according to analytical technique applied are presented. In Annex 2, the different approaches for methylmercury measurements are presented in moredetail. In Annex 3, the questionnaire data are presented. Annex 4 compiles all the CCQM-K43 information documents.JRC.D.4 - Isotope measurement
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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