Residual thermoluminescence for sun-bleached quartz: dependence on pre-exposure radiation dose.

thermoluminescence, à paraître dans Quaternary GeochronologyQuartz grains zeroed by heat and subsequently irradiated - either in the laboratory, or naturally in volcanic deposits - were exposed to sunlight for several months prior to TL measurements. As a result, the residual TL, either Blue or Red, appeared to grow significantly with the radiation-dose experienced by the grains since zeroing. In another experiment, un-heated sedimentary quartz grains, sampled at the very surface of a coastal sand-dune, were irradiated and subsequently exposed to sunlight before TL measurements. The residual Red-TL still exhibited a strong dose-dependence, but at a level which was higher than the natural signal. Finally, it was concluded that the so-called “un-bleachable TL” is not a constant, intrinsic data, for a given quartz sample. Because the residual TL is strongly correlated to the radiation dose experienced since the last zeroing by heat, it can theoretically be quoted in terms of “dose”, as sometimes done. However, this raises the question of its correct evaluation, and, on the other hand, there is a risk of misinterpretation of its physical meaning in the case of un-heated sediments. In the context of sediment dating, the experimentally-estimated residual signal that is routinely subtracted from the total signal for palaeodose estimation is therefore higher than the signal that would have been measured prior to burial. Such effect induces an error which can be significant for Red TL. It can be corrected for, at least roughly, from experimental exploration of the dose-dependence of the residual T

L’accompagnement juridique des chercheurs en bibliothèque universitaire et de recherche : une évolution naturelle des services ?

Mémoire d\u27étude de Master traitant de l\u27accompagnement juridique des chercheurs en bibliothèques universitaire et de recherche

Référencer sa revue diamant pas à pas

Cette frise chronologique présente les systèmes d\u27information dans lesquels référencer en priorité sa revue en libre accès

RENEB accident simulation exercise

Purpose: The RENEB accident exercise was carried out in order to train the RENEB participants in coordinating and managing potentially large data sets that would be generated in case of a major radiological event. Materials and methods: Each participant was offered the possibility to activate the network by sending an alerting email about a simulated radiation emergency. The same participant had to collect, compile and report capacity, triage categorization and exposure scenario results obtained from all other participants. The exercise was performed over 27 weeks and involved the network consisting of 28 institutes: 21 RENEB members, four candidates and three non-RENEB partners. Results: The duration of a single exercise never exceeded 10 days, while the response from the assisting laboratories never came later than within half a day. During each week of the exercise, around 4500 samples were reported by all service laboratories (SL) to be examined and 54 scenarios were coherently estimated by all laboratories (the standard deviation from the mean of all SL answers for a given scenario category and a set of data was not larger than 3 patient codes). Conclusions: Each participant received training in both the role of a reference laboratory (activating the network) and of a service laboratory (responding to an activation request). The procedures in the case of radiological event were successfully established and tested

Uncertainty on radiation doses estimated by biological and retrospective physical methods

Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the ‘EURADOS Working Group 10— Retrospective dosimetry’ members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios

Prevalence and Genetic Characterization of Pertactin-Deficient Bordetella pertussis in Japan

The adhesin pertactin (Prn) is one of the major virulence factors of Bordetella pertussis, the etiological agent of whooping cough. However, a significant prevalence of Prn-deficient (Prn−) B. pertussis was observed in Japan. The Prn− isolate was first discovered in 1997, and 33 (27%) Prn− isolates were identified among 121 B. pertussis isolates collected from 1990 to 2009. Sequence analysis revealed that all the Prn− isolates harbor exclusively the vaccine-type prn1 allele and that loss of Prn expression is caused by 2 different mutations: an 84-bp deletion of the prn signal sequence (prn1ΔSS, n = 24) and an IS481 insertion in prn1 (prn1::IS481, n = 9). The frequency of Prn− isolates, notably those harboring prn1ΔSS, significantly increased since the early 2000s, and Prn− isolates were subsequently found nationwide. Multilocus variable-number tandem repeat analysis (MLVA) revealed that 24 (73%) of 33 Prn− isolates belong to MLVA-186, and 6 and 3 Prn− isolates belong to MLVA-194 and MLVA-226, respectively. The 3 MLVA types are phylogenetically closely related, suggesting that the 2 Prn− clinical strains (harboring prn1ΔSS and prn1::IS481) have clonally expanded in Japan. Growth competition assays in vitro also demonstrated that Prn− isolates have a higher growth potential than the Prn+ back-mutants from which they were derived. Our observations suggested that human host factors (genetic factors and immune status) that select for Prn− strains have arisen and that Prn expression is not essential for fitness under these conditions

Realising the European network of biodosimetry: RENEB-status quo

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB). The RENEB project started in January 2012 involving cooperation of 23 organisations from 16 European countries. The purpose of RENEB is to increase the biodosimetry capacities in case of large-scale radiological emergency scenarios. The progress of the project since its inception is presented, comprising the consolidation process of the network with its operational platform, intercomparison exercises, training activities, proceedings in quality assurance and horizon scanning for new methods and partners. Additionally, the benefit of the network for the radiation research community as a whole is addressed