Two-fluid simulations using local Landau-fluid closures derived from linear theory provide an efficient computational framework for plasma modelling, since they bridge the gap between computationally intensive kinetic simulations and fluid descriptions. Their accuracy in representing kinetic effects depends critically on the validity of the linear approximation used in the derivation: the plasma should not be too far from local thermodynamic equilibrium (LTE). However, many of the problems where these models are of particular interest (such as plasma turbulence and instabilities) are in fact quite far from LTE. The question then arises as to whether kinetic-scale processes are still sufficiently well captured outside of the theoretical regime of applicability of the closure. In this paper, we show that two-fluid simulations with Landau-fluid closures can effectively reproduce the energy spectra obtained with fully kinetic Vlasov simulations, used as references, as long as the local closure parameter is appropriately chosen. Our findings validate the usage of two-fluid simulations with a Landau-fluid closure as a possible alternative to fully kinetic simulations of turbulence, in cases where being able to simulate extremely large domains is of particular interest.

It is generally assumed that noun-noun compounds in English are stressed on the left-hand member (e.g. cóurtroom, watchmaker). However, there is a large amount of variation in stress assignment (e.g. silk tíe, Madison Ávenue, singer-sóngwriter) whose significance and sources are largely unaccounted for in the literature. This article presents a study in which three kinds of factors held to play a role in compound stress assignment are tested: argument structure, lexicalization, and semantics. The analysis of 4,353 noun-noun compounds extracted from the Boston University Radio Speech Corpus shows that there is indeed a considerable amount of variation in stress assignment. Overall, semantics turns out to have the strongest effect on compound stress assignment, whereas an approach relying on argument structure is much less successful in predicting compound stress. The article presents for the first time large-scale empirical evidence for the assumption that lexicalization has an effect on compound stress assignment. The article also makes a methodological contribution to the debate in showing that (and how) corpus-based studies using acoustic measurements can shed new light on the issue of variable compound stress.

This article compares an extensive collection of English loanwords into Korean with a corpus of perceptual responses to English productions by Korean students of English in Korea. The analysis selects ten obstruents situated in four prosodic contexts: initial, final, and pre- and poststress intervocalic positions. Analyses compare the mapping of the obstruents onto Korean categories in the two databases, finding a strong logistic relationship between them, which indicates a process of loanword adaptation as a regularization of the cross-language perception patterns. This conclusion is also supported by differences in the maps across the prosodic positions, wherein loanword differences are correlated with perceptual differences, and by the fact that loanword adaptations are more variable for consonants that do not have a very robust perceptual map. The data, however, also exhibit exceptional cases that apparently indicate effects of a historical lexicalization of individual forms, as well as of an explicit sociocultural standard. Thus, loanword adaptation in this case, though largely indicative of a perceptual base, is more than just synchronic perception.