2,462 research outputs found

    Internet Surveys by Direct Mailing: An Innovative Way of Collecting Data

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    This article describes a new method of collecting data by direct mailing via the Internet. Feasibility and capacities were evaluated through a worldwide opinion poll on global future risks of mankind and potential solutions. Within 1 day, a structured questionnaire was sent to 8,859 randomly selected e-mail addresses. One thousand seven hundred and thirteen were remailed properly completed, 90 within 4 days. Most respondents were residents of North America (64) and Europe (21 ), male (87), and 30 years old on average. Environmental destruction (52) was mentioned as the primary problem, followed by violence (45) and unemployment (45). Education (71 ) was the most frequently proposed solution to future problems. It is obvious that Internet surveys at this time are not repre sentative of the total population. However, they open new dimensions in the interrogation of experts and opinion leaders, especially considering their efficiency and potential for automation

    Perceived Vertical and Lateropulsion: Clinical Syndromes, Localization, and Prognosis

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    We present a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex: yaw, roll, and pitch. The plane-specific syndromes are determined by ocular motor, postural, and percep tual signs. Yaw plane signs are horizontal nystagmus, past pointing, rotational and lat eral body falls, deviation of perceived straight-ahead to the left or right. Roll plane signs are torsional nystagmus, skew deviation, ocular torsion, tilts of head, body, and perceived vertical in a clockwise or counterclockwise direction. Pitch plane signs are upbeat/downbeat nystagmus, forward/backward tilts and falls, deviations of the per ceived horizon. The thus defined vestibular syndromes allow a precise topographic analysis of brainstem lesions according to their level and side. Special emphasis is placed on the vestibular roll plane syndromes of ocular tilt reaction, lateropulsion in Wallenberg's syndrome, thalamic and cortical astasia and their association with roll plane tilt of perceived vertical. Recovery is based on a functionally significant central compensation of a vestibular tone imbalance, the mechanism of which is largely un known. Physical therapy may facilitate this central compensation, but this has not yet been proven in prospective studies

    Cognitive Rhythms Reluctantly Revisited

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.In response to the Power (1983) - Beattie (1984) controversy, a more general critique of the construct of cognitive rhythms is presented. It is argued that the term itself is a misnomer, that the relevance of articulation rate has been neglected, that fluent and hesitant phases of cognitive rhythms have been assessed both subjectively and intuitively, that the speech-production model underlying the concept is simplistic, and that the empirical evidence is based on an extraordinarily small corpus which has been described inadequately in the research literature

    Organizational Mortality of Small Firms: The Effects of Entrepreneurial Age and Human Capital

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    This paper addresses the issue of internal determination of organizational outcomes. It is argued that in small and simply structured organizations a considerable proportion of the variance in organizational activities and outcomes is associated with individuals. In particular, the paper uses human capital theory to derive hypotheses about individual determinants of organizational mortality. These hypotheses are tested with event-history data of firm registrations and de-registrations in a West German region. The hypotheses are corroborated by the data, but the effects may nonetheless be due to processes linking individual characteristics with organizational performance other than those suggested by the human capital approach

    Sultan, dynasty & state in the Ottoman Empire: political institutions in the 16th century

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    From its inception around 1300, 'the House of Osman' maintained the ancient Eurasian steppe tradition which kept the system of suc cession open. At a sultan's death, the throne went to the best candidate to emerge in a contest. By the end of sixteenth century, dynastic strug gles, amounting to civil war and the killing of all the brothers of a successful prince, had caused disquiet in Ottoman polity. Subse quently, rules of succession favoured seniority due to circumstances of the age and lifespan of sultans. Also in the sixteenth century, the grand vezir established a personal administration. By the end of the century, the sultan, though himself no longer a charismatic military leader, curtailed the emergence of a minister in charge of policy. Ot toman polity remained a dynastic empire to its end which deliberately curtailed the emergence of independent political institutions

    Monitoring of Heavy Metals By Energy Dispersive X-Ray Fluorescence Spectrometry

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Fundamentals and salient features of a projected heavy metals monitoring system are discussed. Determination of mass concentrations is achieved by using a new dust emission monitor, consisting of a "Zero Pressure Probe" for isokinetic sampling, which is connected to a "Longitudinally Oscillating Band" mass detector. The thin dust layer, precipitated on the surface of heat resistant filter tapes could be analysed nondestructively by energy-dispersive X-ray fluorescence (EDXRF). Using a small portable EDXRF-system with radioisotope-excitation, quasi-continuous monitoring of particulate heavy metals (Cd, Hg, Pb, Cu, Sb, Zn, Sn) suspended in incinerator stack gases is expected to be feasible. Another application of EDXRF-analysis is the reported investigation of electrostatic precipitator ash (ESP-fly ash). Using the "Linear Multi-Elemental-Standard Addition Method" as a fast and simple routine technique, results are reported for the concentrations of Pb, Cd, Cu and Zn in fly ash samples which had been collected in different fields (hoppers) of the electrostatic precipitator

    Use of Nuclear Magnetic Resonance Imaging Angiography to Follow-Up Arterial Remodeling in an Animal Model

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    Appropriately sized arteries in small animals may be possible models for studying the remodeling process as occurs after arterial balloon injury in humans. Magnetic resonance imaging (MRI) is able to noninvasively image tissue in vivo. To date, small animal angiog raphy models have mostly used research-dedicated instruments and resolution, which are not universally available.Experiments were carried out on a rat aorta model of remodeling in vivo (n=40). Arteries were injured by oversized balloon dilation; control arteries were uninjured. Angiography imaging was performed immediately before sacrifice with an unmodified clinical MRI unit, a 1.5 Tesla MR tomograph with a 20-cm-diameter coil. Longitudinal MRI pictures of the aorta and morphometry of tissue sections to measure luminal and arterial wall areas were analyzed with use of computer-assisted techniques.Comparison of dimensions demonstrated correlation between MRI and histology measurements of the lumen. MRI and morphometry showed a gradual increase in mean luminal area over 6 weeks following injury. The lumen increase correlated with total arterial area and thickness.In this rat aorta model, remodeling documented at histology was followed-up in vivo. The use of such clinical MRI scanners has potential to reduce animal numbers needed to follow-up the remodeling process after therapeutic intervention
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