5,678 research outputs found

    Contributions of temporal encodings of voicing, voicelessness, fundamental frequency, and amplitude variation to audiovisual and auditory speech perception

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    Auditory and audio-visual speech perception was investigated using auditory signals of invariant spectral envelope that temporally encoded the presence of voiced and voiceless excitation, variations in amplitude envelope and F-0. In experiment 1, the contribution of the timing of voicing was compared in consonant identification to the additional effects of variations in F-0 and the amplitude of voiced speech. In audio-visual conditions only, amplitude variation slightly increased accuracy globally and for manner features. F-0 variation slightly increased overall accuracy and manner perception in auditory and audio-visual conditions. Experiment 2 examined consonant information derived from the presence and amplitude variation of voiceless speech in addition to that from voicing, F-0, and voiced speech amplitude. Binary indication of voiceless excitation improved accuracy overall and for voicing and manner. The amplitude variation of voiceless speech produced only a small increment in place of articulation scores. A final experiment examined audio-visual sentence perception using encodings of voiceless excitation and amplitude variation added to a signal representing voicing and F-0. There was a contribution of amplitude variation to sentence perception, but not of voiceless excitation. The timing of voiced and voiceless excitation appears to be the major temporal cues to consonant identity. (C) 1999 Acoustical Society of America. [S0001-4966(99)01410-1]

    Risk communication in emergency response to a simulated extreme flood.

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    Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties

    Holidaying in a disaster zone isn't as crazy as it might seem

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    This article focuses on the valuable role of volunteer tourism in the recovery of tourism to Nepal following the 2015 earthquake. It shows that sustainable tourism practices can positively contribute to post disastare rebuilding

    Narrative, identity, and recovery from serious mental illness: A life history of a runner

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    In recent years, researchers have investigated the psychological effects of exercise for people with mental health problems, often by focusing on how exercise may alleviate symptoms of mental illness. In this article I take a different tack to explore the ways in which exercise contributed a sense of meaning, purpose, and identity to the life of one individual named Ben, a runner diagnosed with schizophrenia. Drawing on life history data, I conducted an analysis of narrative to explore the narrative types that underlie Ben's stories of mental illness and exercise. For Ben, serious mental illness profoundly disrupted a pre-existing athletic identity removing agency, continuity, and coherence from his life story. By returning to exercise several years later, Ben reclaimed his athletic identity and reinstated some degree of narrative agency, continuity, and coherence. While the relationships between narrative, identity, and mental health are undoubtedly complex, Ben's story suggests that exercise can contribute to recovery by being a personally meaningful activity which reinforces identity and sense of self

    Adventures in Holographic Dimer Models

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    We abstract the essential features of holographic dimer models, and develop several new applications of these models. First, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Second, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure. In a simple toy model, the topology of the band structure experiences an interesting reorganization as we vary the strength of the double trace deformations. Finally, we develop tools that would allow one to build, in a bottom-up fashion, a holographic avatar of the Hubbard model.Comment: 22 pages, 8 figures; v2: brief description of case of pure D5 lattice added in sec.3; v3: minor typo fixed; v4: minor change

    Geochemical Characterization of Base Metals in Stream Water and Sediments in the Caddo Lake Watershed, Cass, Harrison, and Marion Counties, Texas

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    The Caddo Lake watershed is located in northeastern Texas and encompasses much of Cass, Harrison, and Marion counties. The watershed is drained by major streams and tributaries flowing in an easterly direction over Eocene-aged rocks and sediments of the Wilcox and Claiborne groups, and empty into the western arm of Caddo Lake. Since 1995, Caddo Lake and some of its tributaries have been included on the State of Texas Clean Water Act 303(d) list by the Texas Commission on Environmental Quality (TCEQ) for impairment due to mercury content in edible tissue, depressed dissolved oxygen, base metal concentrations, and low pH values. The purpose of this multi-year study was to characterize base metal concentrations in stream water and sediments in the Caddo Lake watershed, and document the potential watershed transport and contribution to the impairment of Caddo Lake. Recent water (n = 58) and sediment (n = 116) sampling at 29 sites revealed copper, lead, and zinc concentrations within normal limits and below EPA actionable standards. Mercury concentrations were elevated at 21 of the 29 sampling sites, which could lead to methylation and bioavailability to organisms at all trophic level

    Holographic Wilsonian flows and emergent fermions in extremal charged black holes

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    We study holographic Wilsonian RG in a general class of asymptotically AdS backgrounds with a U(1) gauge field. We consider free charged Dirac fermions in such a background, and integrate them up to an intermediate radial distance, yielding an equivalent low energy dual field theory. The new ingredient, compared to scalars, involves a `generalized' basis of coherent states which labels a particular half of the fermion components as coordinates or momenta, depending on the choice of quantization (standard or alternative). We apply this technology to explicitly compute RG flows of charged fermionic operators and their composites (double trace operators) in field theories dual to (a) pure AdS and (b) extremal charged black hole geometries. The flow diagrams and fixed points are determined explicitly. In the case of the extremal black hole, the RG flows connect two fixed points at the UV AdS boundary to two fixed points at the IR AdS_2 region. The double trace flow is shown, both numerically and analytically, to develop a pole singularity in the AdS_2 region at low frequency and near the Fermi momentum, which can be traced to the appearance of massless fermion modes on the low energy cut-off surface. The low energy field theory action we derive exactly agrees with the semi-holographic action proposed by Faulkner and Polchinski in arXiv:1001.5049 [hep-th]. In terms of field theory, the holographic version of Wilsonian RG leads to a quantum theory with random sources. In the extremal black hole background the random sources become `light' in the AdS_2 region near the Fermi surface and emerge as new dynamical degrees of freedom.Comment: 37 pages (including 8 pages of appendix), 10 figures and 2 table

    Clones in Graphs

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    Finding structural similarities in graph data, like social networks, is a far-ranging task in data mining and knowledge discovery. A (conceptually) simple reduction would be to compute the automorphism group of a graph. However, this approach is ineffective in data mining since real world data does not exhibit enough structural regularity. Here we step in with a novel approach based on mappings that preserve the maximal cliques. For this we exploit the well known correspondence between bipartite graphs and the data structure formal context (G,M,I)(G,M,I) from Formal Concept Analysis. From there we utilize the notion of clone items. The investigation of these is still an open problem to which we add new insights with this work. Furthermore, we produce a substantial experimental investigation of real world data. We conclude with demonstrating the generalization of clone items to permutations.Comment: 11 pages, 2 figures, 1 tabl

    Banishing AdS ghosts with a UV cutoff

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    A recent attempt to make sense of scalars in AdS with "Neumann boundary conditions" outside of the usual BF-window −(d/2)2<m2l2<−(d/2)2+1-(d/2)^2 < m^2 l^2 < -(d/2)^2 + 1 led to pathologies including (depending on the precise context) either IR divergences or the appearance of ghosts. Here we argue that such ghosts may be banished by imposing a UV cutoff. It is also possible to achieve this goal in certain UV completions. An example is the above AdS theory with a radial cutoff supplemented by particular boundary conditions on the cutoff surface. In this case we explicitly identify a region of parameter space for which the theory is ghost free. At low energies, this theory may be interpreted as the standard dual CFT (defined with "Dirichlet" boundary conditions) interacting with an extra scalar via an irrelevant interaction. We also discuss the relationship to recent works on holographic fermi surfaces and quantum criticality.Comment: 20 pages, 9 figure
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