18 research outputs found

    A Theory-Based Approach for a Modular System of Interactive Decision Aids

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    In web stores, a large amount of product information is easily available for consumers. This often leads to information overload on the consumer-side which decreases user-satisfaction and can cause purchase deferral. Therefore, our goal is to prevent consumers from information overload by supporting the cumbersome process of comparing and evaluating products. We propose easy to understand, interactive decision aids, called interactive information management tools such as filtering, sorting and scoring. The contribution of this paper is to (1) retrieve guidelines for designing such tools from both literature on decision behavior research and information systems, and (2) build a prototype following these guidelines. The prototype is evaluated in two usability studies

    Site-controlled growth of InP/GaInP quantum dots on GaAs substrates

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    A technology platform for the epitaxial growth of site-controlled InP quantum dots (QDs) on GaAs substrates is presented. Nanoholes are patterned in a GaInP layer on a GaAs substrate by electron beam lithography and dry chemical etching, serving as QD nucleation centers. The effects of a thermal treatment on the structured surfaces for deoxidation are investigated in detail. By regrowth on these surfaces, accurate QD positioning is obtained for square array arrangements with lattice periods of 1.25 mu m along with a high suppression of interstitial island formation. The optical properties of these red-emitting QDs (lambda similar to 670 nm) are investigated by means of ensemble-and micro-photoluminescence spectroscopy at cryogenic temperatures.</p

    Left atrial remodeling, early repolarization pattern, and inflammatory cytokines in professional soccer players

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    OBJECTIVES: Although regular physical exercise clearly reduces cardiovascular morbidity risk, long-term endurance sports practice has been recognized as a risk factor for atrial fibrillation (AF). However, the mechanisms how endurance sports can lead to AF are not yet clear. The aim of our present study was to investigate the influence of long-term endurance training on vagal tone, atrial size, and inflammatory profile in professional elite soccer players. METHODS: A total of 25 professional major league soccer players (mean age 24+/-4 years) and 20 sedentary controls (mean age 26+/-3 years) were included in the study and consecutively examined. All subjects underwent a sports cardiology check-up with physical examination, electrocardiography, echocardiography, exercise testing on a bicycle ergometer, and laboratory analysis [standard laboratory and cytokine profile: interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, IL-8, IL-10]. RESULTS: Athletes were divided into two groups according to presence or absence of an early repolarization (ER) pattern, defined as a ST-segment elevation at the J-point (STE) >/=0.1mm in 2 leads. Athletes with an ER pattern showed significantly lower heart rate and an increased E/e' ratio compared to athletes without an ER pattern. STE significantly correlated with E/e' ratio as well as with left atrial (LA) volume. The pro-inflammatory cytokines IL-6, IL-8, TNF-alpha as well as the anti-inflammatory cytokine IL-10 were significantly elevated in all soccer players. However, athletes with an ER pattern had significantly higher IL-6 plasma levels than athletes without ER pattern. Furthermore, athletes with "high" level IL-6 had significantly larger LA volumes than players with "low" level IL-6. CONCLUSIONS: Athletes with an ER pattern had significantly higher E/e' ratios, reflecting higher atrial filling pressures, higher LA volume, and higher IL-6 plasma levels. All these factors may contribute to atrial remodeling over time and thus increase the risk of AF in long-term endurance sports

    Site-controlled InP/GaInP quantum dots emitting single photons in the red spectral range

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    We report on site-controlled growth of InP/GaInP quantum dots (QDs) on GaAs substrates. The QD nucleation sites are defined by shallow nanoholes etched into a GaInP layer. Optimized growth conditions allow us to realize QD arrays with excellent long range ordering on nanohole periods as large as 1.25 mu m. Single QD lines with an average linewidth of 553 mu eV and best values below 200 mu eV are observed. Photoluminescence spectroscopy reveals excitonic and biexcitonic emission in the wavelength range of about 670 nm (1.85 eV) with an exciton-biexciton splitting of 1.8 meV. Second-order photon-autocorrelation measurements show clear single photon emission with g((2))(0) = 0.13 +/- 0.01. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690872]</p
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