Search for: All records

Abstract ContextIdeally, connectivity models would be developed using animal movement data because connectivity is fundamentally specific to species and movement processes. However, it can take years to collect sufficient data for all species of interest. Generalized multispecies connectivity models developed from expert opinion might help in the meantime. ObjectivesWe aimed to evaluate how well two common types of circuit theory-based generalized multispecies connectivity models (park-to-park and omnidirectional) predict areas important for animal movement for many species and movement processes. MethodsUsing GPS locations from 3525 individuals belonging to 17 species from 46 study areas across Canada and five tests, we assessed connectivity model prediction accuracy against movement processes measured at different scales, from within home range to presumed dispersal. ResultsAreas important for movement were accurately predicted for 52 to 78% of the datasets and movement processes. Prediction accuracy was lower for fast movements. The omnidirectional model was slightly better at predicting areas important for multiple movement processes. Both models were more accurate for species known to be more averse to human disturbance (72–78% of tests were accurate) compared to species less averse to human disturbance, steep slopes, and/or high elevations (38–41% of tests were accurate). ConclusionsOur study demonstrates that both park-to-park and omnidirectional multispecies connectivity models can predict areas important for various movements for many species and can be used for time-sensitive projects aimed at landscape-scale connectivity conservation. However, because the models were less accurate for some species and faster movements, species-specific connectivity models may be required for informing land management decisions. 

This manuscript reports on the direct observation of a $\beta$ -delayed two-neutron emission in a study of ${}^{134}\mathrm{In}$ at the ISOLDE Decay Station using neutron spectroscopy. We also report on the first measurement in ${\beta }^{-}$ decay of the long-sought $13/2^{+}$ excited state in ${}^{133}\mathrm{Sn}$ , attributed to be the neutron single-particle $i_{13/2}$ orbital. The observation of sequential neutron emission is used to extract the relative population of the $i_{13/2}$ state, which was found to be much smaller than the predictions of the statistical model. The experiment was possible because of the innovative use of a neutron array with neutron discrimination and interaction tracking capabilities. This is the first study of the details of the two-neutron emission for a nucleus, which belongs to the $r$ -process path. Understanding $\beta$ -delayed two-neutron emission probabilities is essential to validate models used in astrophysical $r$ -process nucleosynthesis calculations. Observing two-neutron emissions in ${\beta }^{-}$ decay paves the way for new experiments to study energy and angular correlations for $\beta$ -delayed multineutron emitters. 

Abstract Photonuclear reactions of light nuclei below a mass of$$A=60$$ $A=60$ are planned to be studied experimentally and theoretically with the PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project. Two experimental methods, virtual photon excitation by proton scattering and real photo absorption by a high-brilliance$$\gamma $$ $\gamma$ -ray beam produced by laser Compton scattering, will be applied to measure the photoabsorption cross sections and decay branching ratio of each decay channel as a function of the photon energy. Several nuclear models, e.g. anti-symmetrized molecular dynamics, mean-field and beyond-mean-field models, a large-scale shell model, and ab initio models, will be employed to predict the photonuclear reactions. The uncertainty in the model predictions will be evaluated based on the discrepancies between the model predictions and experimental data. The data and predictions will be implemented in the general reaction calculation code, . The results will be applied to the simulation of the photo-disintegration process of ultra-high-energy cosmic rays in inter-galactic propagation. 

Excited states of the 64Cu (Z=29,N=35) nucleus have been probed using heavy-ion-induced fusion evaporation reaction and an array of Compton-suppressed Clovers as detection system for the emitted γ rays. More than 50 new transitions have been identified and the level scheme of the nucleus has been established up to an excitation energy Ex∼6 MeV and spin ∼10ℏ. The experimental results have been compared with those from large-basis shell-model calculations that facilitated an understanding of the single-particle configurations underlying the level structure of the nucleus.