3,050 research outputs found

    Counting (3+1) - Avoiding permutations

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    A poset is {\it (\3+\1)-free} if it contains no induced subposet isomorphic to the disjoint union of a 3-element chain and a 1-element chain. These posets are of interest because of their connection with interval orders and their appearance in the (\3+\1)-free Conjecture of Stanley and Stembridge. The dimension 2 posets PP are exactly the ones which have an associated permutation π\pi where i≺ji\prec j in PP if and only if i<ji<j as integers and ii comes before jj in the one-line notation of π\pi. So we say that a permutation π\pi is {\it (\3+\1)-free} or {\it (\3+\1)-avoiding} if its poset is (\3+\1)-free. This is equivalent to π\pi avoiding the permutations 2341 and 4123 in the language of pattern avoidance. We give a complete structural characterization of such permutations. This permits us to find their generating function.Comment: 17 page

    Tracking Oregon's Progress: A Report of the Tracking Oregon's Progress (TOP) Indicators Project

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    In 1989, Oregon embarked on a novel experiment to track the progress of the state toward a set of economic, social and environmental goals embodied in the state strategic plan Oregon Shines. The task of tracking a set of indicators to measure progress was assigned to a new state entity: the Oregon Progress Board. For two decades, the Progress Board measured the state's progress using a set of social, economic and environmental indicators. After the 2009 report was completed however, the state decided not to continue funding the Progress Board and discontinued the tracking of state and county indicators.This 2014 report is a report to the people of Oregon. It identifies trends in the state that suggest both progress toward prosperity as well as issues that may be a source of future barriers and concerns. Like those who led previous indicator efforts, we hope that the report and website will be used by policymakers, government analysts, the press, business and civic leaders and the civically-engaged population to better understand the current social, economic, and environmental condition of the state

    Imaging speech production using fMRI

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    Human speech is a well-learned, sensorimotor, and ecological behavior ideal for the study of neural processes and brain-behavior relations. With the advent of modern neuroimaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), the potential for investigating neural mechanisms of speech motor control, speech motor disorders, and speech motor development has increased. However, a practical issue has limited the application of fMRI to issues in spoken language production and other related behaviors (singing, swallowing). Producing these behaviors during volume acquisition introduces motion-induced signal changes that confound the activation signals of interest. A number of approaches, ranging from signal processing to using silent or covert speech, have attempted to remove or prevent the effects of motioninduced artefact. However, these approaches are flawed for a variety of reasons. An alternative approach, that has only recently been applied to study single-word production, uses pauses in volume acquisition during the production of natural speech motion. Here we present some representative data illustrating the problems associated with motion artefacts and some qualitative results acquired from subjects producing short sentences and orofacial nonspeech movements in the scanner. Using pauses or silent intervals in volume acquisition and block designs, results from individual subjects result in robust activation without motion-induced signal artefact. This approach is an efficient method for studying the neural basis of spoken language production and the effects of speech and language disorders using fMRI
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