1,498 research outputs found

    Static and dynamic hyperinflation during severe acute exacerbations of chronic obstructive pulmonary disease

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    Background: Static hyperinflation is known to be increased during moderate acute exacerbations of chronic obstructive pulmonary disease (COPD) (AECOPD), but few data exist in patients with severe exacerbations of COPD. The role of dynamic hyperinflation during exacerbations is unclear. Methods: In a prospective, observational cohort study, we recruited patients admitted to hospital for AECOPD. The following measurements were performed upon admission and again after resolution (stable state) at least 42 days later: inspiratory capacity (IC), body plethysmography, dynamic hyperinflation by metronome-paced IC measurement, health-related quality of life and dyspnea. Results: Forty COPD patients were included of whom 28 attended follow-up. The IC was low at admission (2.05 +/- 0.11 L) and increased again during resolution by 15.6%+/- 23.1% or 0.28 +/- 0.08 L (mean +/- standard error of the mean, p Conclusion: Static hyperinflation is increased during severe AECOPD requiring hospitalization compared with stable state. We could measure metronome-paced dynamic hyperinflation during severe AECOPD but found no increase

    Effects of memory load and distraction on performance and event-related slow potentials in a visuospatial working memory task

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    Brain electrical activity related to working memory was recorded at 15 scalp electrodes during a visuospatial delayed response task. Participants (N = 18) touched the remembered position of a target on a computer screen after either a 1 or 8 sec delay. These memory trials were compared to sensory trials in which the target remained present throughout the delay and response periods. Distracter stimuli identical to the target were briefly presented during the delay on 30% of trials. Responses were less accurate in memory than sensory trials, especially after the long delay. During the delay slow potentials developed that were significantly more negative in memory than sensory trials. The difference between memory and sensory trials was greater at anterior than posterior electrodes. On trials with distracters, the slow potentials generated by memory trials showed further enhancement of negativity whereas there were minimal effects on accuracy of performance. The results provide evidence that engagement of visuospatial working memory generates slow wave negativity with a timing and distribution consistent with frontal activation. Enhanced brain activity associated with working memory is required to maintain performance in the presence of distraction. © 1997 by the Massachusetts Institute of Technolog

    Стратегії та підходи до реструктуризації підприємств сфери ЖКГ в умовах реформування власності України

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    Наведено результати дослідження існуючих підходів до стратегічних напрямів реструктуризації підприємств сфери ЖКГ в умовах реформування власності. Ключові слова: стратегія реструктуризації, ЖКГ України, реструктуризація підприємства, антикризове управління, стратегічний менеджмент.Приведены результаты исследования существующих подходов в стратегических направлениях реструктуризации предприятий сферы ЖКГ в условиях реформирования собственности. Ключевые слова: стратегия реструктуризации, ЖКХ Украины, реструктуризация предприятия, антикризисное управление, стратегический менеджмент.The paper presents the results of studying the approaches in strategic directions of restructuring of housing and communal enterprises under property reformation in Ukraine. Keywords: strategy of restructuring, housing and communal facilities of Ukraine, restructuring of enterprise, anti-crisis management, strategic management

    Strong ellipticity and spectral properties of chiral bag boundary conditions

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    We prove strong ellipticity of chiral bag boundary conditions on even dimensional manifolds. From a knowledge of the heat kernel in an infinite cylinder, some basic properties of the zeta function are analyzed on cylindrical product manifolds of arbitrary even dimension.Comment: 16 pages, LaTeX, References adde

    Two Photon Contribution to Polarization in K+π+μ+μK^+ \rightarrow \pi^+ \mu^+ \mu^-

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    Short distance physics involving virtual top and charm quarks contributes to μ+\mu^+ (and μ\mu^-) polarization in the decay K+π+μ+μK^+ \rightarrow \pi^+ \mu^+ \mu^-. Measurement of the parity violating asymmetry (ΓRΓL)/(ΓR+ΓL)(\Gamma_R - \Gamma_L)/(\Gamma_R + \Gamma_L), where ΓR\Gamma_R and ΓL\Gamma_L are the rates to produce right and left-handed μ+\mu^+, may provide valuable information on the unitarity triangle. The parity violating asymmetry also gets a contribution from Feynman diagrams with two photon intermediate states. We estimate this two photon contribution to the asymmetry and discuss briefly the two photon contribution to time reversal odd asymmetries that involve both the μ+\mu^+ and μ\mu^- polarizations.Comment: (19 pages, 5 figures available on request. Uses phyzzx), CALT-68-1798, UCSD/PTH 92-2

    Orthographic and semantic priming effects in neighbour cognates: Experiments and simulations

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    To investigate how orthography and semantics interact during bilingual visual word recognition, Dutch–English bilinguals made lexical decisions in two masked priming experiments. Dutch primes and English targets were presented that were either neighbour cognates (boek – BOOK), noncognate translations (kooi – CAGE), orthographically related neighbours (neus – NEWS), or unrelated words (huid - COAT). Prime durations of 50 ms (Experiment 1) and 83 ms (Experiment 2) led to similar result patterns. Both experiments reported a large cognate facilitation effect, a smaller facilitatory noncognate translation effect, and the absence of inhibitory orthographic neighbour effects. These results indicate that cognate facilitation is in large part due to orthographic-semantic resonance. Priming results for each condition were simulated well (all r's >.50) by Multilink+, a recent computational model for word retrieval. Limitations to the role of lateral inhibition in bilingual word recognition are discussed

    Listening In on the Past: What Can Otolith δ18O Values Really Tell Us about the Environmental History of Fishes?

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    Oxygen isotope ratios from fish otoliths are used to discriminate marine stocks and reconstruct past climate, assuming that variations in otolith δ18O values closely reflect differences in temperature history of fish when accounting for salinity induced variability in water δ18O. To investigate this, we exploited the environmental and migratory data gathered from a decade using archival tags to study the behaviour of adult plaice (Pleuronectes platessa L.) in the North Sea. Based on the tag-derived monthly distributions of the fish and corresponding temperature and salinity estimates modelled across three consecutive years, we first predicted annual otolith δ18O values for three geographically discrete offshore sub-stocks, using three alternative plausible scenarios for otolith growth. Comparison of predicted vs. measured annual δ18O values demonstrated >96% correct prediction of sub-stock membership, irrespective of the otolith growth scenario. Pronounced inter-stock differences in δ18O values, notably in summer, provide a robust marker for reconstructing broad-scale plaice distribution in the North Sea. However, although largely congruent, measured and predicted annual δ18O values of did not fully match. Small, but consistent, offsets were also observed between individual high-resolution otolith δ18O values measured during tag recording time and corresponding δ18O predictions using concomitant tag-recorded temperatures and location-specific salinity estimates. The nature of the shifts differed among sub-stocks, suggesting specific vital effects linked to variation in physiological response to temperature. Therefore, although otolith δ18O in free-ranging fish largely reflects environmental temperature and salinity, we counsel prudence when interpreting otolith δ18O data for stock discrimination or temperature reconstruction until the mechanisms underpinning otolith δ18O signature acquisition, and associated variation, are clarified
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