Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0 to 970 V/cm. For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V/cm. We also report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from $^{83m}$Kr internal conversion electrons is comparable to that from $^{207}$Bi conversion electrons, we obtained the numbers of excitons ($N_{ex}$) and ion pairs ($N_i$) and their ratio ($N_{ex}/N_i$) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.Comment: v2 to reflect published versio

A Synthesis of Tagging Studies Examining the Behaviour and Survival of Anadromous Salmonids in Marine Environments

This paper synthesizes tagging studies to highlight the current state of knowledge concerning the behaviour and survival of anadromous salmonids in the marine environment. Scientific literature was reviewed to quantify the number and type of studies that have investigated behaviour and survival of anadromous forms of Pacific salmon (Oncorhynchus spp.), Atlantic salmon (Salmo salar), brown trout (Salmo trutta), steelhead (Oncorhynchus mykiss), and cutthroat trout (Oncorhynchus clarkii). We examined three categories of tags including electronic (e.g. acoustic, radio, archival), passive (e.g. external marks, Carlin, coded wire, passive integrated transponder [PIT]), and biological (e.g. otolith, genetic, scale, parasites). Based on 207 papers, survival rates and behaviour in marine environments were found to be extremely variable spatially and temporally, with some of the most influential factors being temperature, population, physiological state, and fish size. Salmonids at all life stages were consistently found to swim at an average speed of approximately one body length per second, which likely corresponds with the speed at which transport costs are minimal. We found that there is relatively little research conducted on open-ocean migrating salmonids, and some species (e.g. masu [O. masou] and amago [O. rhodurus]) are underrepresented in the literature. The most common forms of tagging used across life stages were various forms of external tags, coded wire tags, and acoustic tags, however, the majority of studies did not measure tagging/handling effects on the fish, tag loss/failure, or tag detection probabilities when estimating survival. Through the interdisciplinary application of existing and novel technologies, future research examining the behaviour and survival of anadromous salmonids could incorporate important drivers such as oceanography, tagging/handling effects, predation, and physiology

Identifying and managing frailty in a Brazil context

Objective: The objective of this review is to scope the evidence on how researchers, health, and social care professionals in Brazil currently identify and manage frailty in older adults. / Introduction: The rapidly aging population and associated increased healthcare usage by older people with frailty are challenging the sustainability of healthcare for older people in Brazil. Understanding how frailty is identified, measured, categorized, and managed in Brazil is an important part of building a response to the challenge. / Inclusion criteria: This scoping review will consider studies that included older Brazilian adults (≥60 years old) recruited from different settings (community, primary care, health care centers, hospital, and long-term care institutions). Studies will be included if they involved any kind of frailty assessment (tools, scales, and measures) and/or interventions. This review will consider all study designs, regardless of their rigor. National policies for older people will be also be considered for analysis. / Methods: Indexed and gray literature in English or Portuguese from 2001 to the present will be considered. The searches will be conducted using bibliographic databases, university repositories, and the Brazilian Government official database. The studies will be independently screened according to the inclusion criteria by two reviewers based on their title, abstract, and full text. In case of disagreement, a third reviewer will be consulted. A customized data extraction form will be used to extract data from the included studies. The results will be presented in tabular form, accompanied by a narrative summary related to the objective of the present scoping review

New isomer in 80Y

The ß+/EC decay of mass-separated A = 80 nuclei was studied by means of ß- and γ-ray spectroscopy after the bombardment of a 24Mg target with 58Ni ions at 190 MeV. A new 1- isomer at 228.5(1) keV has been identified in 80Y with a half-life of 4.7(3) s. This new isomer decays to the 4- ground state with an 81(2)% branch and by ß+/EC transitions to levels in 80Sr with a 19(2)% branch. The half-life of the 80Y ground-state decay has been remeasured to be 30.1(5) s. A level scheme for the low-lying states in 80Y is presented. Hartree-Fock-Bogolyubov calculations show a large prolate deformation for these states, and two-quasiparticle + rotor model calculation results suggest that the low-lying states can be reproduced by inclusion of an effective proton-neutron residual interaction. The dominating Nilsson configurations for the 4- ground state and the 1- isomeric state have been found to originate from the parallel and antiparallel coupling of the proton [422]5/2+ and the neutron [301]3/2- orbitals

Half-Life Measurement for the r p-Process Waiting Point Nuclide 80Zr

X-ray bursts have been suggested as a possible site for the astrophysical rp-process. The time scale for the process is governed by β-decay half-lives of several even-even N = Z waiting point nuclei, in particular, N = Z = 40 80Zr. A 4.1(+0.8-0.6)-s β+/EC half-life for 80Zr was determined by observing delayed 84-keV γ rays depopulating a T1/2 = 4-μs isomer at 312 keV in the daughter 80Y. As this half-life is lower than many previously predicted values, the calculated excessive production of A = 80 nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides