8,323 research outputs found

    A computer model of auditory efferent suppression: Implications for the recognition of speech in noise

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    The neural mechanisms underlying the ability of human listeners to recognize speech in the presence of background noise are still imperfectly understood. However, there is mounting evidence that the medial olivocochlear system plays an important role, via efferents that exert a suppressive effect on the response of the basilar membrane. The current paper presents a computer modeling study that investigates the possible role of this activity on speech intelligibility in noise. A model of auditory efferent processing [ Ferry, R. T., and Meddis, R. (2007). J. Acoust. Soc. Am. 122, 3519?3526 ] is used to provide acoustic features for a statistical automatic speech recognition system, thus allowing the effects of efferent activity on speech intelligibility to be quantified. Performance of the ?basic? model (without efferent activity) on a connected digit recognition task is good when the speech is uncorrupted by noise but falls when noise is present. However, recognition performance is much improved when efferent activity is applied. Furthermore, optimal performance is obtained when the amount of efferent activity is proportional to the noise level. The results obtained are consistent with the suggestion that efferent suppression causes a ?release from adaptation? in the auditory-nerve response to noisy speech, which enhances its intelligibility

    Management of atherosclerotic extracranial carotid artery stenosis

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    Atherosclerosis leading to stenosis of the internal carotid artery is the underlying cause of 8–15% of ischaemic strokes (symptomatic carotid stenosis). 1–2% of the adult population have asymptomatic carotid stenosis. Clinical trials in patients with symptomatic carotid stenosis showed a higher procedural risk of non-disabling stroke with stenting versus endarterectomy, but a higher risk of myocardial infarction, cranial nerve palsy, and access site haematoma with endarterectomy. Apart from procedural complications, both treatments are equally effective in preventing stroke and recurrent severe carotid stenosis in the medium-to-long term. Endarterectomy has a modest effect in preventing stroke among patients with asymptomatic carotid stenosis, whereas the role of stenting remains to be established. With advances in medical therapy against atherosclerosis, benefit from invasive therapy has become uncertain. Risk modelling, with the inclusion of brain and carotid plaque imaging, will become increasingly important in selecting patients for interventions

    Justifications in Constraint Handling Rules for Logical Retraction in Dynamic Algorithms

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    We present a straightforward source-to-source transformation that introduces justifications for user-defined constraints into the CHR programming language. Then a scheme of two rules suffices to allow for logical retraction (deletion, removal) of constraints during computation. Without the need to recompute from scratch, these rules remove not only the constraint but also undo all consequences of the rule applications that involved the constraint. We prove a confluence result concerning the rule scheme and show its correctness. When algorithms are written in CHR, constraints represent both data and operations. CHR is already incremental by nature, i.e. constraints can be added at runtime. Logical retraction adds decrementality. Hence any algorithm written in CHR with justifications will become fully dynamic. Operations can be undone and data can be removed at any point in the computation without compromising the correctness of the result. We present two classical examples of dynamic algorithms, written in our prototype implementation of CHR with justifications that is available online: maintaining the minimum of a changing set of numbers and shortest paths in a graph whose edges change.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

    Calculating the random guess scores of multiple-response and matching test items

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    For achievement tests, the guess score is often used as a baseline for the lowest possible grade for score to grade transformations and setting the cut scores. For test item types such as multiple-response, matching and drag-and-drop, determin-ing the guess score requires more elaborate calculations than the more straight-forward calculation of the guess score for True-False and multiple-choice test item formats. For various variants of multiple-response and matching types with respect to dichotomous and polytomous scoring, methods for determining the guess score are presented and illustrated with practical applications. The implica-tions for theory and practice are discussed

    Gypsy and Traveller and Travelling Showpeople accommodation assessment : Maidstone : Final report

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    In September 2011 Maidstone Borough Council commissioned the Salford Housing & Urban Studies Unit (SHUSU) at the University of Salford to produce a Gypsy, Traveller and Travelling Showpeople Accommodation Assessment for the borough. The primary purpose of this report is to provide an evidence base to inform the future development of planning policies through the Local Development Framework. This report presents the projection of requirements for the following periods: 2011 – 2016; 2016 – 2021; 2021 – 2026. The assessment was undertaken by conducting a review of the following data sources: previous assessments of need and information submitted through the previous regional planning process; the policy and guidance context; the bi-annual Caravan Count; information from the local authority with regards to pitch provision and supply; information from key stakeholders; a survey of 115 Gypsy, Traveller and Travelling Showpeople households currently residing in Maidstone borough

    Gypsy, Traveller and Travelling Showpeople accommodation assessment : Sevenoaks : Final report

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    In September 2011 Sevenoaks District Council commissioned the Salford Housing & Urban Studies Unit (SHUSU) at the University of Salford to produce a Gypsy, Traveller and Travelling Showpeople Accommodation Assessment for the district. The primary purpose of this report is to provide an evidence base to inform the future development of planning policies through the Local Development Framework. This report presents the projection of requirements for the following periods: 2012 – 2016; 2017 – 2021; 2022 – 2026. The assessment was undertaken by conducting a review of the following data sources: previous assessments of need and information submitted through the previous regional planning process; the policy and guidance context; the bi-annual Caravan Count; information from the local authority with regards to pitch provision and supply; information from key stakeholders; a survey of 86 Gypsy, Traveller and Travelling Showpeople households currently residing in Sevenoaks District

    Solihull Gypsy and Traveller accommodation assessment : Final report

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    In November 2011 Solihull Metropolitan Borough Council commissioned the Salford Housing & Urban Studies Unit (SHUSU) at the University of Salford to produce a Gypsy, Traveller and Travelling Showpeople Accommodation Assessment for the borough. The primary purpose of this report is to provide an evidence base to inform the future development of planning policies through the Local Development Framework. This report presents the projection of requirements for the following periods: 1st January 2012 – 31st December 2016; 1st January 2017 – 31st December 2021; 1st January 2022 – 31st December 2026. The assessment was undertaken by conducting a review of the following data sources: previous assessments of need and information submitted through the previous regional planning process; the policy and guidance context; the bi-annual Caravan Count; information from the local authority with regards to pitch provision and supply; and a survey of 75 Gypsies and Travellers currently residing in site-based and bricks and mortar accommodation across the borough of Solihull

    Incidence, impact, and predictors of cranial nerve palsy and haematoma following carotid endarterectomy in the international carotid stenting study.

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    OBJECTIVE: Cranial nerve palsy (CNP) and neck haematoma are complications of carotid endarterectomy (CEA). The effects of patient factors and surgical technique were analysed on the risk, and impact on disability, of CNP or haematoma in the surgical arm of the International Carotid Stenting Study (ICSS), a randomized controlled clinical trial of stenting versus CEA in patients with symptomatic carotid stenosis. MATERIALS AND METHODS: A per-protocol analysis of early outcome in patients receiving CEA in ICSS is reported. Haematoma was defined by the surgeon. CNP was confirmed by an independent neurologist. Factors associated with the risk of CNP and haematoma were investigated in a binomial regression analysis. RESULTS: Of the patients undergoing CEA, 45/821 (5.5%) developed CNP, one of which was disabling (modified Rankin score = 3 at 1 month). Twenty-eight (3.4%) developed severe haematoma. Twelve patients with haematoma also had CNP, a significant association (p 14 days (RR 3.33, 95% CI 1.05 to 10.57). The risk of haematoma was increased in women, by the prescription of anticoagulant drugs pre-procedure and in patients with atrial fibrillation, and was decreased in patients in whom a shunt was used and in those with a higher baseline cholesterol level. CONCLUSIONS: CNP remains relatively common after CEA, but is rarely disabling. Women should be warned about an increased risk. Attention to haemostasis might reduce the incidence of CNP. ICSS is a registered clinical trial: ISRCTN 25337470

    Marine ecosystem community carbon and nutrient uptake stoichiometry under varying ocean acidification during the PeECE III experiment

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    Changes to seawater inorganic carbon and nutrient concentrations in response to the deliberate CO2 perturbation of natural plankton assemblages were studied during the 2005 Pelagic Ecosystem CO2 Enrichment (PeECE III) experiment. Inverse analysis of the temporal inorganic carbon dioxide system and nutrient variations was used to determine the net community stoichiometric uptake characteristics of a natural pelagic ecosystem perturbed over a range of pCO2 scenarios (350, 700 and 1050 μatm). Nutrient uptake showed no sensitivity to CO2 treatment. There was enhanced carbon production relative to nutrient consumption in the higher CO2 treatments which was positively correlated with the initial CO2 concentration. There was no significant calcification response to changing CO2 in Emiliania huxleyi by the peak of the bloom and all treatments exhibited low particulate inorganic carbon production (~15 μmol kg−1). With insignificant air-sea CO2 exchange across the treatments, the enhanced carbon uptake was due to increase organic carbon production. The inferred cumulative C:N:P stoichiometry of organic production increased with CO2 treatment from 1:6.3:121 to 1:7.1:144 to 1:8.25:168 at the height of the bloom. This study discusses how ocean acidification may incur modification to the stoichiometry of pelagic production and have consequences for ocean biogeochemical cycling
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