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ABSTRACT AimThe aim of the current study is to conduct a comprehensive phylogenetic analysis of the genusArbaciato elucidate the evolution and phylogenetic relationships among all extant species and reevaluate the presence of geographic structure within species that have wide, fragmented distributions. LocationSpecimens ofArbaciawere collected from 34 localities spanning the Atlantic and Pacific Oceans, and the Mediterranean Sea. MethodsWe obtained sequences from three mitochondrial markers (COI, 16S and the control region and adjacent tRNAs) and two nuclear markers (28S and 18S; the latter ultimately excluded from the final analyses). Phylogenetic trees were constructed using maximum likelihood and Bayesian inference approaches. A time‐calibrated phylogenetic tree was inferred using a relaxed Bayesian molecular clock and three fossil calibration points. ResultsOur analysis supports the monophyly of the genusArbacia, including the speciesArbacia nigra(previously assigned to the monotypic genusTetrapygus). The new phylogenetic topology suggests an alternative biogeographic scenario of initial divergence between Atlantic and Pacific subclades occurring approximately 9 million years ago. The dispersal and subsequent diversification of the Pacific subclade to the southeast Pacific coincides with the onset of glacial and interglacial cycles in Patagonia. In the Atlantic subclade, the split betweenA. punctulataandA. lixulaoccurred 3.01–6.30 (median 3.74 million years ago), possibly associated with the strengthening of the Gulf Stream current connecting the western and eastern Atlantic. Our study also reveals significant genetic and phylogeographic structures within both Atlantic species, indicating ongoing differentiation processes between populations. Main ConclusionOur study provides valuable insights into the evolutionary history and biogeography of the genusArbaciaand highlights the complex interplay between historical climate changes and oceanic currents in shaping the distribution and diversification of echinoids in the Atlantic and Pacific Oceans. 

This work investigates the accuracy, efficiency, and applicability of coarse-grained (CG) atomistic methods in simulation of phonon dynamics. First, we compute and compare phonon dispersion relations in CG models with those in atomically resolved models, using the concurrent atomistic-continuum (CAC). The CG atomistic models using the CAC method are shown to reproduce long-wavelength phonons with great accuracy, while capturing the dynamics of some short-wavelength phonons that are usually inaccessible to CG methods. We then present CG simulation results of the propagation of heat pulses in Si with the interaction between atoms being modelled with the Stillinger-Weber potential; the experimentally observed phonon-focusing patterns in the (1 0 0) and (1 1 1) planes of Si crystals are reproduced. The accuracy and efficiency of the CAC method in CG simulation of acoustic and optical phonon branches are quantified with respect to atomically-resolved molecular dynamics simulations. The applicability and limitations of concurrent multiscale methods in the simulation of phonon transport across atomistic-continuum interface are investigated. Possible ways to overcome the limitations are discussed. 

We present the measurement of ${\pi }^{+}$ -argon inelastic cross sections using the ProtoDUNE single-phase liquid argon time projection chamber in the incident ${\pi }^{+}$ kinetic energy range of 500–800 MeV in multiple exclusive channels (absorption, charge exchange, and the remaining inelastic interactions). The results of this analysis are important inputs to simulations of liquid argon neutrino experiments such as the Deep Underground Neutrino Experiment and the Short Baseline Neutrino program at Fermi National Accelerator Laboratory. They will be employed to improve the modeling of final state interactions within neutrino event generators used by these experiments, as well as the modeling of ${\pi }^{+}$ -argon secondary interactions within the liquid argon. This is the first measurement of ${\pi }^{+}$ -argon absorption at this kinetic energy range as well as the first ever measurement of ${\pi }^{+}$ -argon charge exchange.