High-precision excited state lifetime measurements in rare earth nuclei using LaBr3(Ce) detectors

To study how collective nuclear structure evolves towards mid-shell and test next-generation LaBr3(Ce) scintillation detectors, measurements of the lifetimes of 2+ 1 states in 168Hf and 174W were conducted at the Wright Nuclear Structure Laboratory. Prel

Evolution of collectivity near mid-shell from excited-state lifetime measurements in rare earth nuclei

The B(E2) excitation strength of the first excited 2+ state in even-even nuclei should directly correlate with the size of the valence space and maximize at mid-shell. A previously found saturation of B(E2) strengths in well-deformed rotors at mid-shell is tested through high-precision measurements of the lifetimes of the lowest-lying 2+ states of the Hf168 and W174 rare earth isotopes. Measurements were performed using fast LaBr3 scintillation detectors. Combined with the recently remeasured B(E2;2+1→0+1) values for Hf and W isotopes the new data remove discrepancies observed in the differentials of B(E2) values for these isotope

Excited State Lifetime Measurements in Rare Earth Nuclei with Fast Electronics

We investigated the collectivity of the lowest excited 2⁺ states of even-even rare earth nuclei. The B(E2) excitation strengths of these nuclei should directly correlate to the size of the valence space, and maximize at mid-shell. The previously identified saturation of B(E2) strength in well-deformed rotors at mid-shell is put to a high precision test in this series of measurements. Lifetimes of the 2⁺1 states in ¹⁶⁸Hf and ¹⁷⁴W have been measured using the newly developed LaBr₃ scintillation detectors. The excellent energy resolution in conjunction with superb time properties of the new material allows for reliable handling of background, which is a source of systematic error in such experiments. Preliminary lifetime values are obtained and discussed in the context of previous and ongoing work

\u3cem\u3eg\u3c/em\u3e Factor of the 2\u3csup\u3e+\u3c/sup\u3e\u3csub\u3e1\u3c/sub\u3e State of \u3csup\u3e172\u3c/sup\u3eHf

The g factor of the 2+1 state of 172Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2+1) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the IBA on the valence space. The undershooting of the empirical g factors near midshell in both models suggests that they underestimate the role of the saturation of collectivity, which is explicitly incorporated into a phenomenological model that agrees better with the data

Research priorities for European paediatric emergency medicine

Objective Research in European Paediatric Emergency Medicine (REPEM) network is a collaborative group of 69 paediatric emergency medicine (PEM) physicians from 20 countries in Europe, initiated in 2006. To further improve paediatric emergency care in Europe, the aim of this study was to define research priorities for PEM in Europe to guide the development of future research projects. Design and Setting We carried out an online survey in a modified three-stage Delphi study. Eligible participants were members of the REPEM network. In stage 1, the REPEM steering committee prepared a list of research topics. In stage 2, REPEM members rated on a 6-point scale research topics and they could add research topics and comment on the list for further refinement. Stage 3 included further prioritisation using the Hanlon Process of Prioritisation (HPP) to give more emphasis to the feasibility of a research topic. Results Based on 52 respondents (response rates per stage varying from 41% to 57%), we identified the conditions 'fever', 'sepsis' and 'respiratory infections', and the processes/interventions 'biomarkers', 'risk stratification' and 'practice variation' as common themes of research interest. The HPP identified highest priority for 4 of the 5 highest prioritised items by the Delphi process, incorporating prevalence and severity of each condition and feasibility of undertaking such research. Conclusions While the high diversity in emergency department (ED) populations, cultures, healthcare systems and healthcare delivery in European PEM prompts to focus on practice variation of ED conditions, our defined research priority list will help guide further collaborative research efforts within the REPEM network to improve PEM care in Europe.publishersversionPeer reviewe

Learning an Executable Neural Semantic Parser

This paper describes a neural semantic parser that maps natural language utterances onto logical forms which can be executed against a task-specific environment, such as a knowledge base or a database, to produce a response. The parser generates tree-structured logical forms with a transition-based approach which combines a generic tree-generation algorithm with domain-general operations defined by the logical language. The generation process is modeled by structured recurrent neural networks, which provide a rich encoding of the sentential context and generation history for making predictions. To tackle mismatches between natural language and logical form tokens, various attention mechanisms are explored. Finally, we consider different training settings for the neural semantic parser, including a fully supervised training where annotated logical forms are given, weakly-supervised training where denotations are provided, and distant supervision where only unlabeled sentences and a knowledge base are available. Experiments across a wide range of datasets demonstrate the effectiveness of our parser.Comment: In Journal of Computational Linguistic