The Impact Of Cold Dark Matter Variants On The Halos Of The First Stars And Galaxies: Angular Momentum And Vortex Creation In BEC Dark Matter

If cold dark matter elementary particles form a Bose-Einstein condensate, their superfluidity may distinguish them from other forms of cold dark matter, including the creation of quantum vortices. We have shown that such vortices are favored in strongly-coupled condensates. Vortex creation causes central densities to drop, thus affecting the dynamics of the gaseous baryonic component and subsequently star formation.Astronom

Rapidly Rotating Bose-Einstein Condensates in Homogeneous Traps

We extend the results of a previous paper on the Gross-Pitaevskii description of rotating Bose-Einstein condensates in two-dimensional traps to confining potentials of the form V(r) = r^s, $2<s <\infty$. Writing the coupling constant as $1/\epsilon^2$ we study the limit $\epsilon \to 0$. We derive rigorously the leading asymptotics of the ground state energy and the density profile when the rotation velocity \Omega tends to infinity as a power of $1/\epsilon$. The case of asymptotically homogeneous potentials is also discussed.Comment: LaTex2e, 16 page

The persistence of L1 patterns in SLA: incidental learning and the boundary crossing constraint

The present study analyses the influence of L1 patterns in the descriptions of motion events by Arab EFL learners. First we establish the differences in the construal of motion events by native speakers of Arabic and English (n=20 for each group). 12 prompts (cartoons) were used where a figure crosses a boundary in a certain manner (running, crawling etc.). In line with the literature (Talmy 1985, 1991, 2000a, 2000b and Slobin 1987 et passim), Arab native speakers avoid the use of manner of motion verbs in the description of these events in their first language and use simple path verbs (e.g. enter, go etc.), whereas speakers of English mostly use manner verbs. These deeply engrained differences between L1 and L2 are a learning challenge in SLA. The same prompts were used with two groups of Arab EFL learners (intermediate, n = 34; advanced, n = 30), who live in the UK. These learners follow the Arabic pattern in English. They use only simple path verbs and avoid the use of manner verbs in the description of the boundary crossings. As the learners do not produce ungrammatical sentences, they will not get negative feedback (e.g. from a teacher) and rely entirely on incidental learning from the input. However, despite the high frequency of these manner verbs in the daily input of the learners, they do not acquire the patterns of the target language even at a high proficiency level. This confirms results from earlier studies with different language pairs (e.g. Larrañaga et al. 2012). L1 patterns in the use of manner verbs with boundary crossings are persistent across proficiency levels in L2, and their influence cannot be overcome simply by exposure to the target language. Implicit learning in this context is hardly possible and explicit teaching and learning is needed to overcome the influence of the first language

What defines language dominance in bilinguals?

This article focuses on the construct of language dominance in bilinguals and the ways in which this construct has been operationalized. Language dominance is often seen as relative proficiency in two languages, but it can also be analyzed in terms of language use—that is, how frequently bilinguals use their languages and how these are divided across domains. Assessing language dominance is important because it has become clear that the level of bilinguals’ proficiency in each language as well as the relative strength of each language affect performance on tasks A key distinction is made between direct measures of language dominance, which assess an aspect of language proficiency (e.g., vocabulary or grammar), and indirect ones, which measure variability in exposure to different languages and bilinguals’ use of them. The article includes an evaluation of the extent to which the latter can be interpreted as a proxy for the former