245 research outputs found

    Status of evaluated data files for 238U in the resonance region

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    Experimental data and evaluated data libraries related to neutron induced reaction cross sections for 238U in the resonance region are reviewed. Based on this review a set of test files is produced to study systematic effects such as the impact of the upper boundary of the resolved resonance region (RRR) and the representation of the infinite diluted capture and in-elastic cross section in the unresolved resonance region (URR). A set of Benchmark experiments was selected and used to verify the test files. Based on these studies recommendations to perform a new evaluation have been defined. This report has been prepared in support to the CIELO (Collaborative International Evaluated Library Organisation) project. The objective of this project is the creation of a world-wide recognised nuclear data file with a focus on six nuclides, i.e. 1H, 16O, 56Fe, 235U, 238U and 239Pu. Within the CIELO project, the Joint Research Centre (JRC) at Geel (B) is in charge of the production of an evaluated cross section data file for neutron induced reaction of 238U in the resonance region.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    New Mediterranean Biodiversity Records (July 2016)

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    This contribution forms part of a series of collective articles published regularly in Mediterranean Marine Science that report on new biodiversity records from the Mediterranean basin. The current article presents 51 geographically distinct records for 21 taxa belonging to 6 Phyla, extending from the western Mediterranean to the Levantine. The new records, per country, are as follows: Spain: the cryptogenic calcareous sponge Paraleucilla magna is reported from a new location in the Alicante region. Algeria: the rare Atlanto-Mediterranean bivalve Cardium indicum is reported from Annaba. Tunisia: new distribution records for the Indo-Pacific lionfish Pterois miles from Zembra Island and Cape Bon. Italy: the ark clam Anadara transversa is reported from mussel cultures in the Gulf of Naples, while the amphipod Caprella scaura and the isopods Paracerceis sculpta and Paranthura japonica are reported as associated to the –also allochthonous–bryozoan Amathia verticillata in the Adriatic Sea; in the latter region, the cosmopolitan Atlantic tripletail Lobotes surinamensisis also reported, a rare finding for the Mediterranean. Slovenia: a new record of the non-indigenous nudibranch Polycera hedgpethi in the Adriatic. Greece: several new reports of the introduced scleractinian Oculina patagonica, the fangtooth moray Enchelycore anatina, the blunthead puffer Sphoeroides pachygaster (all Atlantic), and the lionfish Pterois miles (Indo-Pacific) suggest their ongoing establishment in the Aegean Sea; the deepest bathymetric record of the invasive alga Caulerpa cylindracea in the Mediterranean Sea is also registered in the Kyklades, at depths exceeding 70 m. Turkey: new distribution records for two non indigenous crustaceans, the blue crab Callinectes sapidus (Atlantic origin) and the moon crab Matuta victor (Indo-Pacific origin) from the Bay of Izmir and Antalya, respectively; in the latter region, the Red Sea goatfish Parupeneus forsskali, is also reported. Lebanon: an array of records of 5 alien and one native Mediterranean species is reported by citizen-scientists; the Pacific jellyfish Phyllorhiza punctata and the Indo-Pacific teleosteans Tylerius spinosissimus, Ostracion cubicus, and Lutjanus argentimaculatus are reported from the Lebanese coast, the latter notably being the second record for the species in the Mediterranean Sea since 1977; the native sand snake-eel Ophisurus serpens, rare in the eastern Mediterranean, is reported for the first time from Lebanon, this being its easternmost distribution range; finally, a substantial number of sightings of the lionfish Pterois miles further confirm the current establishment of this lessepsian species in the Levantine

    FENDL: A library for fusion research and applications

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    The Fusion Evaluated Nuclear Data Library (FENDL) is a comprehensive and validated collection of nuclear cross section data coordinated by the International Atomic Energy Agency (IAEA) Nuclear Data Section (NDS). FENDL assembles the best nuclear data for fusion applications selected from available nuclear data libraries and has been under development for decades. FENDL contains sub-libraries for incident neutron, proton, and deuteron cross sections including general purpose and activation files used for particle transport and nuclide inventory calculations. We describe the history, selection of evaluations for the various sub-libraries (neutron, proton, deuteron) with the focus on transport and reactor dosimetry applications, the processing of the nuclear data for application codes, and the development of the TENDL-2017 library which is the currently recommended activation library for FENDL. We briefly describe the IAEA IRDFF library as the recommended library for dosimetry fusion applications. We also present work on validation of the neutron sub-library using a variety of fusion relevant computational and experimental benchmarks. A variety of cross section libraries are used for the validation work including FENDL-2.1, FENDL-3.1d, FENDL-3.2, ENDF/B-VIII.0, and JEFF-3.2 with the emphasis on the FENDL libraries. The results of the experimental validation showed that the performance of FENDL-3.2b is at least as good and in most cases better than FENDL-2.1. Future work will consider improved evaluations developed by the International Nuclear Data Evaluation Network (INDEN). Additional work will be needed to investigate differences in gas production in structural materials. Covariance matrices need to be updated to support the development of fusion technology. Additional validation work for high-energy neutrons, protons and deuterons, and the activation library will be needed.Comment: 81 pages, 114 figure

    Empire Ultimate Expansion: Resonances and Covariances.

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    The EMPIRE code system is being extended to cover the resolved and unresolved resonance region employing proven methodology used for the production of new evaluations in the recent Atlas of Neutron Resonances. Another directions of Empire expansion are uncertainties and correlations among them. These include covariances for cross sections as well as for model parameters. In this presentation we concentrate on the KALMAN method that has been applied in EMPIRE to the fast neutron range as well as to the resonance region. We also summarize role of the EMPIRE code in the ENDF/B-VII.0 development. Finally, large scale calculations and their impact on nuclear model parameters are discussed along with the exciting perspectives offered by the parallel supercomputing

    Study of photo-proton reactions driven by bremsstrahlung radiation of high-intensity laser generated electrons

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    Photo-nuclear reactions were investigated using a high power table-top laser. The laser system at the University of Jena ( I similar to 3-5 x 10(19) W cm(-2)) produced hard bremsstrahlung photons ( kT similar to 2(9 MeV) via a laser-gas interaction which served to induce ( gamma, p) and ( gamma, n) reactions in Mg, Ti, Zn and Mo isotopes. Several ( gamma, p) decay channels were identified using nuclear activation analysis to determine their integral reaction yields

    Sphingomimetic multiple sclerosis drug FTY720 activates vesicular synaptobrevin and augments neuroendocrine secretion

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    Neurotransmission and secretion of hormones involve a sequence of protein/lipid interactions with lipid turnover impacting on vesicle trafficking and ultimately fusion of secretory vesicles with the plasma membrane. We previously demonstrated that sphingosine, a sphingolipid metabolite, promotes formation of the SNARE complex required for membrane fusion and also increases the rate of exocytosis in isolated nerve terminals, neuromuscular junctions, neuroendocrine cells and in hippocampal neurons. Recently a fungi-derived sphingosine homologue, FTY720, has been approved for treatment of multiple sclerosis. In its non-phosphorylated form FTY720 accumulates in the central nervous system, reaching high levels which could affect neuronal function. Considering close structural similarity of sphingosine and FTY720 we investigated whether FTY720 has an effect on regulated exocytosis. Our data demonstrate that FTY720 can activate vesicular synaptobrevin for SNARE complex formation and enhance exocytosis in neuroendocrine cells and neurons

    Evaluation of the Neutron Data Standards

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    With the need for improving existing nuclear data evaluations, (e.g., ENDF/B-VIII.0 and JEFF-3.3 releases) the first step was to evaluate the standards for use in such a library. This new standards evaluation made use of improved experimental data and some developments in the methodology of analysis and evaluation. In addition to the work on the traditional standards, this work produced the extension of some energy ranges and includes new reactions that are called reference cross sections. Since the effort extends beyond the traditional standards, it is called the neutron data standards evaluation. This international effort has produced new evaluations of the following cross section standards: the H(n,n), 6Li(n,t), 10B(n,α), 10B(n,), natC(n,n), Au(n,γ), 235U(n,f) and 238U(n,f). Also in the evaluation process the 238U(n,γ) and 239Pu(n,f) cross sections that are not standards were evaluated. Evaluations were also obtained for data that are not traditional standards: the Maxwellian spectrum averaged cross section for the Au(n,γ) cross section at 30 keV; reference cross sections for prompt γ-ray production in fast neutron-induced reactions; reference cross sections for very high energy fission cross sections; the 252Cf spontaneous fission neutron spectrum and the 235U prompt fission neutron spectrum induced by thermal incident neutrons; and the thermal neutron constants. The data and covariance matrices of the uncertainties were obtained directly from the evaluation procedure

    The joint evaluated fission and fusion nuclear data library, JEFF-3.3

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    The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides 235^{235}U, 238^{238}U and 239^{239}Pu, on 241^{241}Am and 23^{23}Na, 59^{59}Ni, Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includes new fission yields, prompt fission neutron spectra and average number of neutrons per fission. In addition, new data for radioactive decay, thermal neutron scattering, gamma-ray emission, neutron activation, delayed neutrons and displacement damage are presented. JEFF-3.3 was complemented by files from the TENDL project. The libraries for photon, proton, deuteron, triton, helion and alpha-particle induced reactions are from TENDL-2017. The demands for uncertainty quantification in modeling led to many new covariance data for the evaluations. A comparison between results from model calculations using the JEFF-3.3 library and those from benchmark experiments for criticality, delayed neutron yields, shielding and decay heat, reveals that JEFF-3.3 performes very well for a wide range of nuclear technology applications, in particular nuclear energy

    New Mediterranean Biodiversity Records (April, 2019)

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    The Collective Article on “New Mediterranean Biodiversity Records” offers the means to publish biodiversity records in the Mediterranean Sea. The current article presents new biodiversity data information on 18 taxa (14 alien, 3 native and 1 cryptogenic species) belonging to 5 Phyla that are reported for 11 different countries listed according to their geographic position from the western to the eastern Mediterranean Sea. Algeria: the alien green alga Caulerpa taxifolia var. distichophylla and the heterobranchs Aplysia dactylomeda and Aplysia punctata are first reported from the entire country. France: a new record of the alien hydroid Porpita porpita is reported from the Corsican Sea, representing the second record of the species in the western Mediterranean Sea. Tunisia: the alien fish Scatophagus argus is reported from the Gulf of Gabès, probably representing an aquarium release. Italy: the well-established Mediterranean alien bivalve Malleus regula is first reported from the entire country. Slovenia: the alien marine bivalve Xenostrobus securis is reported for the first time from the entire country. Croatia: the alien gastropod Biuve fulvipunctata is reported for the first time from the country but also from the entire Adriatic Sea. Montenegro: the alien bivalve Rapana venosa is reported for the first time from the Montenegrin waters. Albania: the well-established alien fish Lagocephalus sceleratus and the rare native shark Rhizoprionodon acutus are reported for the first from the entire country. Greece: the rare native ray Leucoraja circularis is reported for the first time from the Argolikos Gulf and for the first time for the entire country its identification is confirmed morphologically and molecularly; additional records of the alien nomad jellyfish Rhopilema nomadic document its expanding distribution, while the occurrence and the alien fishes Sillago suezensis and Pomadasys stridens are reported for the first time from Hellenic waters. Turkey: additional records of the Egyptian Prawn Metapenaeopsis aegyptia are reported with some biological information. Cyprus: the alien fish Variola louti is reported for the first time for the entire Mediterranean Sea, probably released from an aquarium, while the alien moon crab Matuta victor is reported for the first time from the entire country

    Setting a baseline for global urban virome surveillance in sewage

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    The rapid development of megacities, and their growing connectedness across the world is becoming a distinct driver for emerging disease outbreaks. Early detection of unusual disease emergence and spread should therefore include such cities as part of risk-based surveillance. A catch-all metagenomic sequencing approach of urban sewage could potentially provide an unbiased insight into the dynamics of viral pathogens circulating in a community irrespective of access to care, a potential which already has been proven for the surveillance of poliovirus. Here, we present a detailed characterization of sewage viromes from a snapshot of 81 high density urban areas across the globe, including in-depth assessment of potential biases, as a proof of concept for catch-all viral pathogen surveillance. We show the ability to detect a wide range of viruses and geographical and seasonal differences for specific viral groups. Our findings offer a cross-sectional baseline for further research in viral surveillance from urban sewage samples and place previous studies in a global perspective
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