237 research outputs found

    Observation of Ground-State Two-Neutron Decay

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    Neutron decay spectroscopy has become a successful tool to explore nuclear properties of nuclei with the largest neutron-to-proton ratios. Resonances in nuclei located beyond the neutron dripline are accessible by kinematic reconstruction of the decay products. The development of two-neutron detection capabilities of the Modular Neutron Array (MoNA) at NSCL has opened up the possibility to search for unbound nuclei which decay by the emission of two neutrons. Specifically this exotic decay mode was observed in 16Be and 26O.Comment: To be published in Acta Physica Polonica

    Exploring the neutron dripline two neutrons at a time: The first observations of the 26O and 16Be ground state resonances

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    The two-neutron unbound ground state resonances of 26^{26}O and 16^{16}Be were populated using one-proton knockout reactions from 27^{27}F and 17^{17}B beams. A coincidence measurement of 3-body system (fragment + n + n) allowed for the decay energy of the unbound nuclei to be reconstructed. A low energy resonance, << 200 keV, was observed for the first time in the 24^{24}O + n + n system and assigned to the ground state of 26^{26}O. The 16^{16}Be ground state resonance was observed at 1.35 MeV. The 3-body correlations of the 14^{14}Be + n + n system were compared to simulations of a phase-space, sequential, and dineutron decay. The strong correlations in the n-n system from the experimental data could only be reproduced by the dineutron decay simulation providing the first evidence for a dineutron-like decay.Comment: Invited Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

    The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts

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    This is the final version of the article. Available from the publisher via the DOI in this record.Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.We thank all colleagues involved in the Arctic Freshwater Synthesis (AFS) for fruitful discussions. In particular, John Walsh is acknowledged for his constructive comments on the manuscript. AFS has been sponsored by the World Climate Research Programme’s Climate and the Cryosphere project (WCRP-CliC), the International Arctic Science Committee (IASC), and the Arctic Monitoring and Assessment Programme (AMAP). The work for this paper has been supported by the Academy of Finland (contracts 259537 and 283101), the UK Natural Environment Research Council (grant NE/J019585/1), the US National Science Foundation grant ARC-1023592 and the Program “Arctic” and the Basic Research Program of the Presidium Russian Academy of Sciences. NCAR is supported by the U.S. National Science Foundation. We gratefully acknowledge the project coordination and meeting support of Jenny Baeseman and Gwenaelle Hamon at the CliC International Project Office. No new data were applied in the manuscript. Data applied for Figures 2 and 3 are available from the JRA-55 archive at http://jra. kishou.go.jp/JRA-55/index_en. html#usage

    Anticholinergic drug burden tools/scales and adverse outcomes in different clinical settings: a systematic review of reviews

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    Background: Cumulative anticholinergic exposure (anticholinergic burden) has been linked to a number of adverse outcomes. To conduct research in this area, an agreed approach to describing anticholinergic burden is needed. Objective: This review set out to identify anticholinergic burden scales, to describe their rationale, the settings in which they have been used and the outcomes associated with them. Methods: A search was performed using the Healthcare Databases Advanced Search of MEDLINE, EMBASE, Cochrane, CINAHL and PsycINFO from inception to October 2016 to identify systematic reviews describing anticholinergic burden scales or tools. Abstracts and titles were reviewed to determine eligibility for review with eligible articles read in full. The final selection of reviews was critically appraised using the ROBIS tool and pre-defined data were extracted; the primary data of interest were the anticholinergic burden scales or tools used. Results: Five reviews were identified for analysis containing a total of 62 original articles. Eighteen anticholinergic burden scales or tools were identified with variation in their derivation, content and how they quantified the anticholinergic activity of medications. The Drug Burden Index was the most commonly used scale or tool in community and database studies, while the Anticholinergic Risk Scale was used more frequently in care homes and hospital settings. The association between anticholinergic burden and clinical outcomes varied by index and study. Falls and hospitalisation were consistently found to be associated with anticholinergic burden. Mortality, delirium, physical function and cognition were not consistently associated. Conclusions: Anticholinergic burden scales vary in their rationale, use and association with outcomes. This review showed that the concept of anticholinergic burden has been variably defined and inconsistently described using a number of indices with different content and scoring. The association between adverse outcomes and anticholinergic burden varies between scores and has not been conclusively established

    National First Peoples Gathering on Climate Change

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    Our purpose in hosting the National First Peoples Gathering on Climate Change (the Gathering) was to celebrate, learn from and enhance First Peoples-led climate action. We set out to strengthen kinships, cultural identity and well-being, and to strengthen caring for Country by using both Indigenous and scientific knowledge. The Gathering supported this overall purpose through five aims:• Bring Traditional Owners together to share with one another about climate change • Share scientific information in a form useful for Traditional Owners• Identify options for policy to respond to climate change • Provide tangible information to take back to communities• Highlight First Peoples’ climate change actions. 110 Traditional Owners from across Australia attended the Gathering

    Spatial search using the discrete time quantum walk

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    We study the quantum walk search algorithm of Shenvi et al. (Phys Rev A 67:052307, 2003) on data structures of one to two spatial dimensions, on which the algorithm is thought to be less efficient than in three or more spatial dimensions. Our aim is to understand why the quantum algorithm is dimension dependent whereas the best classical algorithm is not, and to show in more detail how the efficiency of the quantum algorithm varies with spatial dimension or accessibility of the data. Our numerical results agree with the expected scaling in 2D of O(√N log N}) , and show how the prefactors display significant dependence on both the degree and symmetry of the graph. Specifically, we see, as expected, the prefactor of the time complexity dropping as the degree (connectivity) of the structure is increased
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