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Coarticulation across morpheme boundaries:An ultrasound study of past-tense inflection in Scottish English
No full textIt has been hypothesized that morphologically-complex words are mentally stored in a decomposed form, often requiring online composition during processing. Morphologically-simple words can only be stored as a whole. The way a word is stored and retrieved is thought to influence its realization during speech production, so that when retrieval requires less time, the articulatory plan is executed faster. Faster articulatory execution could result in more coarticulation. Accordingly, we hypothesized that morphologically-simple words might be produced with more coarticulation than apparently homophonous morphologically-complex words, because the retrieval of monomorphemic forms is direct, in contrast to morphologically-complex ones, which might need to be composed online into full word forms. Using Ultrasound Tongue Imaging, we tested this hypothesis with nine speakers of Scottish English. Over two days of training, participants learned phonemically identical monomorphemic and morphologically-complex nonce words, while on the third consecutive testing day, they produced them in two prosodic contexts. Two types of articulatory analyses revealed no systematic differences in coarticulation between monomorphemic and morphologically-complex items, yet a few speakers did idiosyncratically produce some morphological effects on articulation. Our work contributes to our understanding of how morphologically complex words are stored and processed during speech production
The impact of glitches on young pulsar rotational evolution
No full textWe report on a timing programme of 74 young pulsars that have been observed by the Parkes 64-m radio telescope over the past decade. Using modern Bayesian timing techniques, we have measured the properties of 124 glitches in 52 of these pulsars, of which 74 are new. We demonstrate that the glitch sample is complete to fractional increases in spin-frequency greater than 90% g � 9:3 10􀀀9. We measure values of the braking index, n, in 33 pulsars. In most of these pulsars, their rotational evolution is dominated by episodes of spin-down with n > 10, punctuated by step changes in the spin-down rate at the time of a large glitch. The step changes are such that, averaged over the glitches, the long-term n is small. We find a near one-to-one relationship between the inter-glitch value of n and the change in spin-down of the previous glitch divided by the inter-glitch time interval. We discuss the results in the context of a range of physical models
Structural Dynamics and Thermal Transport in Bismuth Chalcogenide Alloys
No full textWe present a detailed study of the structural dynamics, energetic and dynamical stability and thermal transport of the bismuth chalcogenides Bi2S3, Bi2Se3 and Bi2Te3 and their alloys. The active Bi lone pairs lead to competition between orthorhombic Pnma and rhombohedral R3̅m phases, with the latter favored by the heavier chalcogens, while the reported non-ambient Bi2Se3 and Bi2Te3 phases show phonon instabilities under ambient conditions. The Pnma structure has intrinsically weaker chemical bonding and stronger phonon anharmonicity than the R3̅m phase, resulting in lower lattice thermal conductivity. A thermodynamic model of Bi2(Se1-xSx)3 indicates the R3̅m structure is energetically favored only at low S content, but the stability window may be extended with lower formation temperatures. R3̅m Bi2(Se1-xTex)3 is a non-ideal solid solution due to a strong preference for the Se and Te atoms to occupy the interior and exterior sites, respectively, in the constituent quintuple layers. Strain-field fluctuations from chemical bonding inhomogeneities are shown to play an important role in the heat transport in the alloys, and chalcogen disorder is found to be an important factor in the lower thermal conductivity of Bi2SeTe2 compared to Bi2Te3. The microscopic insight from this study provides a new theoretical perspective on the bismuth chalcogenides and their alloys, to inform ongoing research on the thermoelectric performance of these and related system
Enabling older people with mental health needs to engage with community social care: A scoping review to inform a theory of change
No full textDespite apparent need, many older people with cognitive impairment and/or mental health needs do not fully engage with social care. This can manifest in different ways, including passive or aggressive attempts to avoid or repel care workers. However, little is known about how to support such individuals in their own homes and deliver effective care. Against this background, we undertook a scoping review with a view to developing a preliminary theory of change suggesting how care might be modified to engage this client group. The most recent search was conducted on 21/04/21. Papers were included if they i) focused on older people (65+) living at home with social care needs; and ii) described difficulties/problems with the provision/receipt of social care associated with individuals’ mental health needs. Twenty-six citations were identified through electronic database searches and reference screening, and the results were charted according to key theory of change concepts (long- term outcomes, preconditions, interventions, rationale & assumptions). All the included papers related to people with dementia. Four subgroups of papers were identified. The first highlight those external conditions that make it more likely an intervention will be successful; the second describe specific interventions to engage older people who by virtue of their mental health needs have not engaged with social care; the third explore what services can do to increase service uptake by older people with mental health needs and their caregivers more generally; and the fourth details theoretical approaches to explaining the behaviour of people with dementia. Each provides information that could be used to inform care delivery and the development of interventions to improve engagement with health and social care for these individuals. The study concludes that different framing of engagement difficulties, such as that offered through positioning theory, may assist in future service design
FREE OBJECTS IN TRIANGULAR MATRIX VARIETIES AND QUIVER ALGEBRAS OVER SEMIRINGS
No full textWe study the free objects in the variety of semigroups and variety of monoids generated by the monoid of all n×n upper triangular matrices over a commutative semiring. We obtain explicit representations of these, as multiplicative subsemigroups of quiver algebras over polynomial semirings. A case of particular interest is where n = 2 and the semiring is the tropical semifield, where the variety coincides with that generated by the bicyclic monoid (or equivalently, by the free monogenic inverse monoid); here we are obtain faithful representations of the free objects in this variety inside a semidirect product of a commutative monoid acting on a semilattice. We apply these representations to answer several questions, including that of when the given varieties are locally finite
Deoxyribonucleic Acid Polymer Nanoparticle Hydrogels
No full textPolymer nanoparticle hydrogels made of deoxyribonucleic acid and silica have been prepared and shown to display shear thinning and self-healing properties, sustained release of cargo and enzymatic degradation
Interfered-Naming Therapy for Aphasia (INTA): Behavioural and computational effects of a novel linguistic-executive approach
No full textBackground and aims. Executive functions recently have gained attention as important contributor to language performance in aphasia. Picture/word interference embraces both executive control and lexical processing through distracted confrontation naming. Thus, we created a novel approach that embedded interfered-naming into an established lexical therapy framework. We aimed to (1) investigate patients’ behavioural response to distractor types and treatment methods of interfered-naming and (2) determine specific therapy effects on linguistic versus executive processing and initial eligibility criteria. Methods. Persons with word finding difficulties in chronic aphasia received 4-weeks therapy in a block design with thorough pre-post-testing including computational modelling. During therapy, picture naming was distracted by auditory stimuli which were primed by a preceding comprehension task and directly assisted by increasing semantic or phonological cues. Results. 19 participants were included into the diagnostic study, 12 of which also completed the therapy study. Distractor types did not generally yield differential effects at baseline. The novel linguistic-executive treatment significantly improved pure naming in most (9 out of 12) cases, fostered generalisation to untrained items, increased semantic weights in the computational model and reduced automated speech. Therapy gains correlated positively with initial distractor comprehension, lexical-semantics and word discrimination, and negatively with automated speech and conceptual-semantics. Conclusion. The interference paradigm combined with computational modelling offers a useful tool for aphasia diagnosis and the new treatment approach revealed to be effective. Semantic and executive processing appear to be the core source of improvements
Upwardly Abstracted Definition-Based Subontologies
No full textIn this paper, we present a method for extracting subontologies from ELH ontologies for a set of symbols. The approach is focused on the generation of upwardly abstracted definitions of concepts, which is a technique for computing definitions expressed using closest primitive ancestors. The subontologies returned by the method are evaluated for quality and compared to extracts computed with locality-based modularisation and uniform interpolation. Our subontology generation method produces promising results in terms of size and relevance to the needs of domain experts
Distribution coefficient model for zirconium and technetium extraction from nitric acid solution
No full textTechnetium and zirconium are two of the most problematic fission products in the PUREX process due to their complex extraction behaviours. Although there are several published works related to the calculation of Tc and Zr distribution coefficients, the reliability of those methods have to be validated carefully, and further knowledge in this area is still needed. This work is, therefore, devoted to developing technetium and zirconium distribution coefficient models for predicting their distribution between nitric acid solution and tri-butyl phosphate in diluent for solutions containing uranium, technetium and zirconium. The distribution coefficient model for zirconium is based on the organic nitric acid concentration, rather than the free TBP concentration. An improved technetium distribution coefficient model, in the absence of other metals, is also developed. The co-extraction of technetium and zirconium or uranium is calculated by ligand exchange mechanisms. The validation results demonstrate that the distribution coefficient models developed in this work are more accurate than established models
Is the molecular KS relationship universal down to low metallicities?
No full textIn recent years it has been speculated that in extreme low metallicity galactic environments, stars form in regions that lack H2. In this paper we investigate how changing the metallicity and UV-field strength of a galaxy affects the star formation within, and the molecular gas Kennicutt-Schmidt relation. Using extremely high resolution arepo simulations of isolated dwarf galaxies, we independently vary the metallicity and UV-field to between 1% and 10% solar neighbourhood values. We include a non-equilibrium, time-dependant chemical network to model the molecular composition of the ISM, and include the effects of gas shielding from an ambient UV field. Crucially our simulations directly model the gravitational collapse of gas into star-forming clumps and cores and their subsequent accretion using sink particles. In this first publication we find that reducing the metallicity and UV-field by a factor of 10 has no effect on star formation, and minimal effect on the cold, dense star forming gas. The cold gas depletion times are almost an order of magnitude longer than the molecular gas depletion time due to the presence of star formation in HI dominated cold gas. We study the H2 KennicuttSchmidt relationship that arises naturally within the simulations and find a near linear power law index of Ν = 1.09 ± 0.014 in our fiducial 10% solar metallicity model. As the metallicityand UV-field are reduced this becomes moderately steeper, with a slope of Ν =1.24 ± 0.022 for our 1% solar metallicity and 1% solar UV field model