46,546 research outputs found

    Generalized MICZ-Kepler Problems and Unitary Highest Weight Modules

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    For each integer n1n\ge 1, we demonstrate that a (2n+1)(2n+1)-dimensional generalized MICZ-Kepler problem has an \mr{Spin}(2, 2n+2) dynamical symmetry which extends the manifest \mr{Spin}(2n+1) symmetry. The Hilbert space of bound states is shown to form a unitary highest weight \mr{Spin}(2, 2n+2)-module which occurs at the first reduction point in the Enright-Howe-Wallach classification diagram for the unitary highest weight modules. As a byproduct, we get a simple geometric realization for such a unitary highest weight \mr{Spin}(2, 2n+2)-module.Comment: 27 pages, Refs. update

    Building blocks of polarized endomorphisms of normal projective varieties

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    Automatic emotional state detection using facial expression dynamic in videos

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    In this paper, an automatic emotion detection system is built for a computer or machine to detect the emotional state from facial expressions in human computer communication. Firstly, dynamic motion features are extracted from facial expression videos and then advanced machine learning methods for classification and regression are used to predict the emotional states. The system is evaluated on two publicly available datasets, i.e. GEMEP_FERA and AVEC2013, and satisfied performances are achieved in comparison with the baseline results provided. With this emotional state detection capability, a machine can read the facial expression of its user automatically. This technique can be integrated into applications such as smart robots, interactive games and smart surveillance systems

    How are junior doctors managing patients with self-limiting illnesses at their first presentation? A video vignette study

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    Purpose: To conduct a video vignette survey of medical students and doctors investigating test ordering for patients presenting with self-limiting or minor illness. Methods: Participants were shown six video vignettes of common self-limiting illnesses and invited to devise investigation and management plans for the patients’ current presentation. The number of tests ordered was compared with those recommended by an expert panel. A Theory of Planned Behaviour Questionnaire explored participants’ beliefs and attitudes about ordering tests in the context of self-limiting illness. Results: Participants (n=61) were recruited from across Australia. All participants ordered at least one test that was not recommended by the experts in most cases. Presentations that focused mainly on symptoms (eg, in cases with bowel habit disturbance and fatigue) resulted in more tests being ordered. A test not recommended by experts was ordered on 54.9% of occasions. With regard to attitudes to test ordering, junior doctors were strongly influenced by social norms. The number of questionable tests ordered in this survey of 366 consultations has a projected cost of $17 000. Conclusions: This study suggests that there is some evidence of questionable test ordering by these participants with significant implications for costs to the health system. Further research is needed to explore the extent and reasons for test ordering by junior doctors across a range of clinical settings

    Automatic Classification of Text Databases through Query Probing

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    Many text databases on the web are "hidden" behind search interfaces, and their documents are only accessible through querying. Search engines typically ignore the contents of such search-only databases. Recently, Yahoo-like directories have started to manually organize these databases into categories that users can browse to find these valuable resources. We propose a novel strategy to automate the classification of search-only text databases. Our technique starts by training a rule-based document classifier, and then uses the classifier's rules to generate probing queries. The queries are sent to the text databases, which are then classified based on the number of matches that they produce for each query. We report some initial exploratory experiments that show that our approach is promising to automatically characterize the contents of text databases accessible on the web.Comment: 7 pages, 1 figur

    New England Cod Collapse and the Climate.

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    To improve fishery management, there is an increasing need to understand the long-term consequences of natural and anthropogenic climate variability for ecological systems. New England's iconic cod populations have been in decline for several decades and have recently reached unprecedented lows. We find that 17% of the overall decline in Gulf of Maine cod biomass since 1980 can be attributed to positive phases of the North Atlantic Oscillation (NAO). This is a consequence of three results: i) a 1-unit increase in the NAO winter index is associated with a 17% decrease in the spring biomass of age-1 cod the following year; ii) this NAO-driven decrease persists as the affected cohort matures; iii) fishing practices appear to exacerbate NAO's direct biological effect such that, since 1913, a 1-unit increase in the NAO index lowers subsequent cod catch for up to 19 years. The Georges Bank cod stock displays similar patterns. Because we statistically detect a delay between the NAO and subsequent declines in adult biomass, our findings imply that observed current NAO conditions can be used in stock forecasts, providing lead time for adaptive policy. More broadly, our approach can inform forecasting efforts for other fish populations strongly affected by natural and anthropogenic climatic variation
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