This study investigated the structure of working memory in young school-age children by testing the fit of three competing theoretical models using a wide variety of tasks. The best fitting models were then used to assess the relationship between working memory and nonverbal measures of fluid reasoning (Gf) and visual processing (Gv) intelligence. One hundred sixty-eight English-speaking 7–9 year olds with typical development, from three states, participated. Results showed that Cowan’s three-factor embedded processes model fit the data slightly better than Baddeley and Hitch’s (1974) three-factor model (specified according to Baddeley, 1986) and decisively better than Baddeley’s (2000) four-factor model that included an episodic buffer. The focus of attention factor in Cowan’s model was a significant predictor of Gf and Gv. The results suggest that the focus of attention, rather than storage, drives the relationship between working memory, Gf, and Gv in young school-age children. Our results do not rule out the Baddeley and Hitch model, but they place constraints on both it and Cowan’s model. A common attentional component is needed for feature binding, running digit span, and visual short-term memory tasks; phonological storage is separate, as is a component of central executive processing involved in task manipulation. The results contribute to a zeitgeist in which working memory models are coming together on common ground (cf. Cowan, Saults, & Blume, 2014; Hu, Allen, Baddeley, & Hitch, 2016).

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The Bubble Nebula (or NGC 7635) is a parsec-scale seemingly spherical wind-blown bubble around the relatively unevolved O star BD+60 • 2522. The young dynamical age of the nebula and significant space velocity of the star suggest that the Bubble Nebula might be a bow shock. We ran 2D hydrodynamic simulations to model the interaction of the wind of the central star with the interstellar medium (ISM). The models cover a range of possible ISM number densities of n = 50−200 cm −3 and stellar velocities of v * = 20−40 km s −1 . Synthetic Hα and 24 µm emission maps predict the same apparent spherical bubble shape with quantitative properties similar to observations. The synthetic maps also predict a maximum brightness similar to that from the observations and agree that the maximum brightness is at the apex of the bow shock. The best-matching simulation had v * ≈ 20 km s −1 into an ISM with n ∼ 100 cm −3 , at an angle of 60 • with respect to the line of sight. Synthetic maps of soft (0.3−2 keV) and hard (2−10 keV) X-ray emission show that the brightest region is in the wake behind the star and not at the bow shock itself. The unabsorbed soft X-rays have a luminosity of ∼10 32 −10 33 erg s −1 . The hard X-rays are fainter: ∼10 30 −10 31 erg s −1 , and may be too faint for current X-ray instruments to successfully observe. Our results imply that the O star creates a bow shock as it moves through the ISM and in turn creates an asymmetric bubble visible at optical and infrared wavelengths and predicted to be visible in X-rays. The Bubble Nebula does not appear to be unique; it could simply be a favourably oriented, very dense bow shock. The dense ISM surrounding BD+60 • 2522 and its strong wind suggest that it could be a good candidate for detecting non-thermal emission.Article published by EDP Sciences A4, page 1 of 16 A&A 625, A4 (2019)

Compared to children with typical development, children with dyslexia, developmental language disorder (DLD), or both often demonstrate working memory deficits. It is unclear how pervasive the deficits are or whether the deficits align with diagnostic category. The purpose of this study was to determine whether different working memory profiles would emerge on a comprehensive battery of central executive, phonological, visuospatial, and binding working memory tasks and whether these profiles were associated with group membership. Method: Three hundred two 2nd graders with typical development, dyslexia, DLD, or dyslexia/DLD completed 13 tasks from the Comprehensive Assessment Battery for Children-Working Memory (Gray, Alt, Hogan, Green, & 1 DLD has historically been referred to as specific language impairment. However, a recent consensus study concluded that the term developmental language disorder should be used instead (Bishop, Snowling, Thompson, Greenhalgh, & the CATALISE-2 Consortium, 2017). Thus, we use the term developmental language disorder throughout the article, except when referring to articles where authors used the term specific language impairment in their research.