403 research outputs found
Detailed Abundance Analysis of the Brightest Star in Segue 2, the Least Massive Galaxy
We present the first high resolution spectroscopic observations of one red
giant star in the ultra-faint dwarf galaxy Segue 2, which has the lowest total
mass (including dark matter) estimated for any known galaxy. These observations
were made using the MIKE spectrograph on the Magellan II Telescope at Las
Campanas Observatory. We perform a standard abundance analysis of this star,
SDSS J021933.13+200830.2, and present abundances of 21 species of 18 elements
as well as upper limits for 25 additional species. We derive [Fe/H] = -2.9, in
excellent agreement with previous estimates from medium resolution
spectroscopy. Our main result is that this star bears the chemical signatures
commonly found in field stars of similar metallicity. The heavy elements
produced by neutron-capture reactions are present, but they are deficient at
levels characteristic of stars in other ultra-faint dwarf galaxies and a few
luminous dwarf galaxies. The otherwise normal abundance patterns suggest that
the gas from which this star formed was enriched by metals from multiple Type
II supernovae reflecting a relatively well-sampled IMF. This adds to the
growing body of evidence indicating that Segue 2 may have been substantially
more massive in the past.Comment: Accepted for publication in MNRAS. 13 pages, 7 figures, 3 tables,
including 1 long machine-readable table availabl
Exhaustification, free-choice, and additivity: Evidence from Sakha da(γanɨ)
This paper discusses some unique semantic properties displayed by the Sakha quantifier particle daγanɨ (often reduced to da). It is shown that, despite significant similarity with well-studied additive TOO-particles such as Japanese -mo and Hungarian -is, da(γanɨ) never clearly serves the role of additive too/also/either, nor does it appear in free-choice items. Adopting an exhaustification-based approach wherein quantifier particles activate grammatical alternatives which are in turn interpreted by covert operators O(nly) or E(ven), it is proposed that da(γanɨ)-marked phrases are typically exhaustified non-recursively
Sakha 'da(qany)': Negative Polarity, Conjunction, and Focus
This paper discusses the quantifier particle da(qany) in the Siberian Turkic language Sakha (also known as "Yakut"). Focusing on its distribution in negative polarity items (NPIs) and doubled coordination constructions, it is shown that it has a distribution which is far more restricted than similar elements in other languages. In order to account for the semantics of this element, it is argued in an exhaustification-based theory of polarity sensitivity, that da(qany)'s main semantic contribution is to mark the alternative of its host as obligatorily active
Tuvan -daa in quantificational noun phrases: Existential or universal?
This paper characterizes the main functions of the Tuvan particle -daa and proposes a semantic analysis, focusing on its role in Quantificational NPs (QNPs), specifically its role in forming Negative Polarity Items (NPIs) and universal quantifiers. It is argued that Tuvan -daa QNPs are underlyingly existentials, with these two main readings being derived from recursive exhaustification of the host's alternatives
Plural Possession in Turkish and Sakha
This paper examines the morphological interaction of possessor agreement and the number of the possessor and possessed noun in Turkish and Sakha, two distantly related Turkic languages. Of particular focus are third-person posses- sors, where both languages can use the regular nominal plural suffix -LAr to index 3PL possessors, and (similar to many Turkic languages) do not allow two instances of -LAr in sequence, resulting in a three-way ambiguity, e.g. Sakha at-tar-ï [horse-PL-3.POSS] a. ‘his/her horses,’ b. ‘their horse,’ c. ‘their horses.’ In Turkish, this ambiguity obtains only with pro-dropped possessors, as an overt plural possessor does not index plurality on singular nouns, whereas in Sakha 3PL agreement is obligatory. It is argued that in Sakha, 3PL possession is true agreement, whereas in Turkish the pattern that obtains under pro-drop is a result of the possessor’s PL feature lowering onto the possessed noun. Further, we examine the nature of the *-lar-lar haplology (i.e. the fact that a 3PL-possessing-PL cannot be marked with -lar twice: e.g. Sakha *at-tar-dar-a [horse-PL-PL-3P] ‘their horses,’ contending that it is a particular property of the exponent -lar which occurs during Vocabulary-Insertion
High-resolution Spectroscopy of Extremely Metal-poor Stars in the Least Evolved Galaxies: Leo IV
We present high-resolution Magellan/MIKE spectroscopy of the brightest star in the ultra-faint dwarf galaxy Leo IV. We measure an iron abundance of [Fe/H] = –3.2, adding to the rapidly growing sample of extremely metal-poor (EMP) stars being identified in Milky Way satellite galaxies. The star is enhanced in the α elements Mg, Ca, and Ti by ~0.3 dex, very similar to the typical Milky Way halo abundance pattern. All of the light and iron-peak elements follow the trends established by EMP halo stars, but the neutron-capture elements Ba and Sr are significantly underabundant. These results are quite similar to those found for stars in the ultra-faint dwarfs Ursa Major II, Coma Berenices, Boötes I, and Hercules, suggesting that the chemical evolution of the lowest-luminosity galaxies may be universal. The abundance pattern we observe is consistent with predictions for nucleosynthesis from a Population III supernova explosion. The extremely low metallicity of this star also supports the idea that a significant fraction (≳10%) of the stars in the faintest dwarfs have metallicities below [Fe/H] = –3.0
Patient-Centric Medicine Design: Key Characteristics of Oral Solid Dosage Forms that Improve Adherence and Acceptance in Older People
Older people represent a very heterogeneous patient population and are the major user group of medication. Age-related changes mean that this population can encounter barriers towards taking medicines orally. The aim of this study was to investigate the characteristics of oral solid dosage forms that contribute to an age appropriate dosage design, with an aim to improve overall medication adherence and acceptance in older people. Fifty-two semistructured interviews were conducted with older people, informal (family) carers, and health and social care professionals. Formulation characteristics impacted three stages of the medication taking process: (1) medication identification and memorability, (2) medication handling and (3) swallowability. Small round tablets (≤7 mm) are least accepted amongst older people and their carers and had a negative impact on all stages. The use of bright, two-coloured preparations and interesting shapes improves identification and further aids memorability of indications and the timing of tablets. Palatability, while useful to enhance swallowability, also has an impact on the visual appeal and memorability of medication. Environmental, patient, medication and disease characteristics also determine preferences for formulation. Developing an age appropriate dosage design for older people, therefore, requires a holistic, patient-centric approach to improve adherence and acceptance
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