151 research outputs found

    The impact of steam on the electronic structure of the selective propane oxidation catalyst MoVTeNb oxide (orthorhombic M1 phase)

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    The selective propane oxidation catalyst MoVTeNb oxide M1 was investigated by microwave conductivity, synchrotron X-ray photoelectron, soft X-ray absorption and resonant photoelectron spectroscopy under reaction conditions to identify the influence of steam on the electronic bulk and surface properties. Steam significantly increases both the conversion of propane and the selectivity to the target product acrylic acid. The increased catalytic performance comes along with a decreased conductivity, a modification of the surface chemical and electronic structure with an enrichment of covalently bonded V5+ species to the extent of Mo6+, a decreased work function and hence polarity of the surface and a modified valence band structure. The higher degree of covalency in metal oxide bonds affects the mobility of the free charge carriers, and hence explains the decrease of the conductivity with steam. Furthermore we could prove that a subsurface space charge region depleted in electrons and thus an upward bending of the electronic band structure are induced by the reaction mixture, which is however not dependent on the steam content

    "WissensWert - Wert des Wissens": Kooperativer Bericht von der ODOK 2012 - 14. Österreichisches Online-Informationstreffen und 15. Österreichischer Dokumentartag in Wels (12.-14. September 2012)

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    cooperative report of the Austrian library conference ODOK "worth knowing - the worth of knowledge", September 201

    Information management functions in national economies. An analysis of the information sector in Austria

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    The information sector has been an area of research for more than 40 years and researchers still try to find different approaches to this topic. The project presented in this contribution approaches the information sector from an information science perspective. Information management functions (IMF) – i.e. all functions and processes related to information selection, acquisition, description, preservation, product creation and services – will serve as a starting point for analysis. The fundamental assumption is that these functions do not occur only in libraries but also in other contexts. Accordingly, economic costs associated with IMF, represented by labor and capital necessary for their performance can be measured in a wide range of contexts, including libraries but also industries of various kinds. One of the main goals of the project is to investigate the extent of IMF in knowledge industries of the Austrian national economy. Since the project uses a methodology developed by Robert M. Hayes, who has already conducted similar research in the U.S., it will be possible to position the project outcome in an international context

    Vorwort und Editorial

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    Auch wenn (berufs-)bildungspolitische Diskussionen um Gleichwertigkeit, DurchlĂ€ssigkeit, Anerkennung und aktuell um Verberuflichung des Akademischen und Akademisierung des Beruflichen eine AnnĂ€herung allgemeiner und beruflicher Bildung vermuten lassen, ist die Frage nach dem VerhĂ€ltnis dieser beiden Bildungen nicht eindeutig gelöst. Vielmehr stehen nach wie vor unterschiedliche Positionen nebeneinander. Im folgenden Beitrag geht es weniger um die Frage danach, was beide Bildungen eint, trennt und wie sie miteinander verbunden werden können. Vielmehr soll sich der Frage angenĂ€hert werden, von welchen ĂŒbergreifenden historischen bildungstheoretischen und -politischen Gedanken und Ereignissen beide Bereiche betroffen waren und sind, und wie diese die VerhĂ€ltnisfrage tangiert und entschieden haben. Unter drei historisch widersprĂŒchlichen Aspekten, von denen sowohl die allgemeine als auch die berufliche Bildung betroffen sind, wird thematisiert, wie diese WidersprĂŒche intern, also im VerhĂ€ltnis zwischen Allgemeinbildung und Berufsbildung als Idee und allgemeiner und beruflicher Bildung als soziale RealitĂ€t historisch gelöst wurden. Zu diesen ĂŒbergreifenden WidersprĂŒchen gehören: Bildung fĂŒr alle und die soziale Portionierung von Bildung, Allseitigkeit von Bildung und Halbbildung und allgemeine NĂŒtzlichkeit von Bildung und Ökonomisierung. Die Frage, die mit diesem Beitrag angestoßen werden soll, ist, wie ĂŒber Bildung ĂŒbergreifend nachgedacht werden kann, damit allgemeine und berufliche Bildung nicht mehr gegeneinander ausgespielt werden und ohne Ungleichwertigkeiten ineinanderfließen, sich abgrenzen und ergĂ€nzen können

    QRS complex and T wave planarity for the efficacy prediction of automatic implantable defibrillators.

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    OBJECTIVE To test the hypothesis that in recipients of primary prophylactic implantable cardioverter-defibrillators (ICDs), the non-planarity of ECG vector loops predicts (a) deaths despite ICD protection and (b) appropriate ICD shocks. METHODS Digital pre-implant ECGs were collected in 1948 ICD recipients: 21.4% females, median age 65 years, 61.5% ischaemic heart disease (IHD). QRS and T wave three-dimensional loops were constructed using singular value decomposition that allowed to measure the vector loop planarity. The non-planarity, that is, the twist of the three-dimensional loops out of a single plane, was related to all-cause mortality (n=294; 15.3% females; 68.7% IHD) and appropriate ICD shocks (n=162; 10.5% females; 87.7% IHD) during 5-year follow-up after device implantation. Using multivariable Cox regression, the predictive power of QRS and T wave non-planarity was compared with that of age, heart rate, left ventricular ejection fraction, QRS duration, spatial QRS-T angle, QTc interval and T-peak to T-end interval. RESULTS QRS non-planarity was significantly (p<0.001) associated with follow-up deaths despite ICD protection with HR of 1.339 (95% CI 1.165 to 1.540) but was only univariably associated with appropriate ICD shocks. Non-planarity of the T wave loop was the only ECG-derived index significantly (p<0.001) associated with appropriate ICD shocks with multivariable Cox regression HR of 1.364 (1.180 to 1.576) but was not associated with follow-up mortality. CONCLUSIONS The analysed data suggest that QRS and T wave non-planarity might offer distinction between patients who are at greater risk of death despite ICD protection and those who are likely to use the defibrillator protection

    QRS micro-fragmentation as a mortality predictor.

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    AIMS Fragmented QRS complex with visible notching on standard 12-lead electrocardiogram (ECG) is understood to represent depolarization abnormalities and to signify risk of cardiac events. Depolarization abnormalities with similar prognostic implications likely exist beyond visual recognition but no technology is presently suitable for quantification of such invisible ECG abnormalities. We present such a technology. METHODS AND RESULTS A signal processing method projects all ECG leads of the QRS complex into optimized three perpendicular dimensions, reconstructs the ECG back from this three-dimensional projection, and quantifies the difference (QRS 'micro'-fragmentation, QRS-ÎŒf) between the original and reconstructed signals. QRS 'micro'-fragmentation was assessed in three different populations: cardiac patients with automatic implantable cardioverter-defibrillators, cardiac patients with severe abnormalities, and general public. The predictive value of QRS-ÎŒf for mortality was investigated both univariably and in multivariable comparisons with other risk factors including visible QRS 'macro'-fragmentation, QRS-Mf. The analysis was made in a total of 7779 subjects of whom 504 have not survived the first 5 years of follow-up. In all three populations, QRS-ÎŒf was strongly predictive of survival (P < 0.001 univariably, and P < 0.001 to P = 0.024 in multivariable regression analyses). A similar strong association with outcome was found when dichotomizing QRS-ÎŒf prospectively at 3.5%. When QRS-ÎŒf was used in multivariable analyses, QRS-Mf and QRS duration lost their predictive value. CONCLUSION In three populations with different clinical characteristics, QRS-ÎŒf was a powerful mortality risk factor independent of several previously established risk indices. Electrophysiologic abnormalities that contribute to increased QRS-ÎŒf values are likely responsible for the predictive power of visible QRS-Mf. KEY QUESTION KEY FINDING TAKE-HOME MESSAGE QRS-ÎŒf is a strong predictor of worsened survival. It can be assessed in standard short-term 12-lead electrocardiograms

    Pulling Back the Curtain on the Wizards of Oz

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    The Wizard of Oz method is an increasingly common practice in HCI and CSCW studies as part of iterative design processes for interactive systems. Instead of designing a fully-fledged system, the ‘technical work’ of key system components is completed by human operators yet presented to study participants as if computed by a machine. However, little is known about how Wizard of Oz studies are interactionally and collaboratively achieved in situ by researchers and participants. By adopting an ethnomethodological perspective, we analyse our use of the method in studies with a voice-controlled vacuum robot and two researchers present. We present data that reveals how such studies are organised and presented to participants and unpack the coordinated orchestration work that unfolds ‘behind the scenes’ to complete the study. We examine how the researchers attend to participant requests and technical breakdowns, and discuss the performative, collaborative, and methodological nature of their work. We conclude by offering insights from our application of the approach to others in the HCI and CSCW communities for using the method

    Lack of Prognostic Value of T-Wave Alternans for Implantable Cardioverter-Defibrillator Benefit in Primary Prevention

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    BACKGROUND: New methods to identify patients who benefit from a primary prophylactic implantable cardioverter-defibrillator (ICD) are needed. T-wave alternans (TWA) has been shown to associate with arrhythmogenesis of the heart and sudden cardiac death. We hypothesized that TWA might be associated with benefit from ICD implantation in primary prevention. METHODS AND RESULTS: In the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter-Defibrillators) study, we prospectively enrolled 2327 candidates for primary prophylactic ICD. A 24-hour Holter monitor reading was taken from all recruited patients at enrollment. TWA was assessed from Holter monitoring using the modified moving average method. Study outcomes were all-cause death, appropriate shock, and survival benefit. TWA was assessed both as a contiguous variable and as a dichotomized variable with cutoff points <47 ÎŒV and <60 ÎŒV. The final cohort included 1734 valid T-wave alternans samples, 1211 patients with ICD, and 523 control patients with conservative treatment, with a mean follow-up time of 2.3 years. TWA ≄60 ÎŒV was a predicter for a higher all-cause death in patients with an ICD on the basis of a univariate Cox regression model (hazard ratio, 1.484 [95% CI, 1.024–2.151]; P=0.0374; concordance statistic, 0.51). In multivariable models, TWA was not prognostic of death or appropriate shocks in patients with an ICD. In addition, TWA was not prognostic of death in control patients. In a propensity score–adjusted Cox regression model, TWA was not a predictor of ICD benefit. CONCLUSIONS: T-wave alternans is poorly prognostic in patients with a primary prophylactic ICD. Although it may be prognostic of life-threatening arrhythmias and sudden cardiac death in several patient populations, it does not seem to be useful in assessing benefit from ICD therapy in primary prevention among patients with an ejection fraction of ≀35%
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