216 research outputs found

    Time-Resolved Data Acquisition for In Situ Subsurface Planetary Geochemistry

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    The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface geochemistry of planetary bodies in situ. All previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on a constant neutron source produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated

    Time-resolved Neutron-gamma-ray Data Acquisition for in Situ Subsurface Planetary Geochemistry

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    The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated

    Northeast Conference on Andean Archaeology and Ethnohistory (NCAAE) Statement on Sexual harassment and Community Values

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    This is a statement on sexual harassment and community values signed by eight members of the Northeast Conference on Andean Archaeology and Ethnohistory (NCAAE)https://digitalcommons.library.umaine.edu/andean_past_special/1008/thumbnail.jp

    STREET: A Multi-Task Structured Reasoning and Explanation Benchmark

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    We introduce STREET, a unified multi-task and multi-domain natural language reasoning and explanation benchmark. Unlike most existing question-answering (QA) datasets, we expect models to not only answer questions, but also produce step-by-step structured explanations describing how premises in the question are used to produce intermediate conclusions that can prove the correctness of a certain answer. We perform extensive evaluation with popular language models such as few-shot prompting GPT-3 and fine-tuned T5. We find that these models still lag behind human performance when producing such structured reasoning steps. We believe this work will provide a way for the community to better train and test systems on multi-step reasoning and explanations in natural language.Comment: Published in ICLR 202

    Outcome of the first Medicines Utilisation Research in Africa Group meeting to promote sustainable and rational medicine use in Africa

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    The first MURIA (Medicines Utilisation Research in Africa) group workshop and symposium brought researchers together from across Africa to improve their knowledge on drug utilisation (DU) methodologies as well as exchange ideas. As a result, progress DU research to formulate future strategies to enhance the rational use of medicines. Anti-infectives was the principal theme for the one day symposium following the workshops. This included presentations on the inappropriate use of antibiotics as well as ways to address this. Concerns with adverse drug reactions and adherence to anti-retroviral medicines was also discussed, with poor adherence remaining a challenge. There were also concerns with the underutilisation of generics. These discussions resulted in a number of agreed activities before the next conference in 2016
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