9,080 research outputs found

    Propositionalism without propositions, objectualism without objects

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    Propositionalism is the view that all intentional states are propositional states, which are states with a propositional content, while objectualism is the view that at least some intentional states are objectual states, which are states with objectual contents, such as objects, properties, and kinds. This paper argues that there are two distinct ways of understanding propositionalism and objectualism: (1) as views about the deep nature of the contents of intentional states, and (2) as views about the superficial character of the contents of intentional states. I argue that we should understand the views in the second way. I also argue that the propositionalism debate is fairly independent from debates over the deep nature of intentionality, and that this has implications for arguments for propositionalism and objectualism from claims about the nature of intentional content. I close with a short discussion of how related points apply to the debate over singular content

    Evolution and nucleosynthesis of helium-rich asymptotic giant branch models

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    There is now strong evidence that some stars have been born with He mass fractions as high as Yβ‰ˆ0.40Y \approx 0.40 (e.g., in Ο‰\omega Centauri). However, the advanced evolution, chemical yields, and final fates of He-rich stars are largely unexplored. We investigate the consequences of He-enhancement on the evolution and nucleosynthesis of intermediate-mass asymptotic giant branch (AGB) models of 3, 4, 5, and 6 MβŠ™_\odot with a metallicity of Z=0.0006Z = 0.0006 ([Fe/H] β‰ˆβˆ’1.4\approx -1.4). We compare models with He-enhanced compositions (Y=0.30,0.35,0.40Y=0.30, 0.35, 0.40) to those with primordial He (Y=0.24Y=0.24). We find that the minimum initial mass for C burning and super-AGB stars with CO(Ne) or ONe cores decreases from above our highest mass of 6 MβŠ™_\odot to ∼\sim 4-5 MβŠ™_\odot with Y=0.40Y=0.40. We also model the production of trans-Fe elements via the slow neutron-capture process (s-process). He-enhancement substantially reduces the third dredge-up efficiency and the stellar yields of s-process elements (e.g., 90% less Ba for 6 MβŠ™_\odot, Y=0.40Y=0.40). An exception occurs for 3 MβŠ™_\odot, where the near-doubling in the number of thermal pulses with Y=0.40Y=0.40 leads to ∼\sim 50% higher yields of Ba-peak elements and Pb if the 13^{13}C neutron source is included. However, the thinner intershell and increased temperatures at the base of the convective envelope with Y=0.40Y=0.40 probably inhibit the 13^{13}C neutron source at this mass. Future chemical evolution models with our yields might explain the evolution of s-process elements among He-rich stars in Ο‰\omega Centauri.Comment: 21 pages, 16 figures, accepted for publication by MNRAS. Stellar yields included as online data table

    Comprehension as social and intellectual practice: Rebuilding curriculum in low socioeconomic and cultural minority schools

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    This article reframes the concept of comprehension as a social and intellectual practice. It reviews current approaches to reading instruction for linguistically and culturally diverse and low socioeconomic students, noting an emphasis on comprehension as autonomous skills. The Four Resources model (Freebody & Luke, 1990) is used to make the case for the integration of comprehension instruction with an emphasis on student cultural and community knowledge, and substantive intellectual and sociocultural content in elementary school curricula. Illustrations are drawn from research underway on the teaching of literacy in primary schools in low SES communities
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