Showing papers by "Johannes Kepler University of Linz published in 2000"

Cultural variation of leadership prototypes across 22 European countries

Abstract: This study sets out to test the assumption that concepts of leadership differ as a function of cultural differences in Europe and to identify dimensions which describe differences in leadership concepts across European countries. Middle-level managers (N = 6052) from 22 European countries rated 112 questionnaire items containing descriptions of leadership traits and behaviours. For each attribute respondents rated how well it fits their concept of an outstanding business leader. The findings support the assumption that leadership concepts are culturally endorsed. Specifically, clusters of European countries which share similar cultural values according to prior cross-cultural research (Ronen & Shenkar, 1985), also share similar leadership concepts. The leadership prototypicality dimensions found are highly correlated with cultural dimensions reported in a comprehensive cross-cultural study of contemporary Europe (Smith, Dugan, & Trompenaars, 1996). The ordering of countries on the leadership dimensions is considered a useful tool with which to model differences between leadership concepts of different cultural origin in Europe. Practical implications for cross-cultural management, both in European and non-European settings, are discussed.

Biotechnology and the European public

Abstract: The latest European sample survey of public perceptions of biotechnology reveals widespread opposition to genetically modified (GM) food in much of Europe, but public attitudes to medical and environmental applications remain positive.

Shadow economies around the world : size, causes, and consequences

Abstract: Using various methods (currency demand, physical input (electricity) method, model approach), which are discussed and criticized, estimates of the size of the shadow economy in 76 developing, transition and OECD-countries are presented. The average size of a shadow economy varies from 12 percent of GDP for OECD, to 23 percent for transition and to 39 percent for developing countries. An increasing burden of taxation and social security contributions combined with rising state regulatory activities are the driving forces for the increase of the shadow economy especially in OECD-countries. According to some findings, a growing shadow economy has a negative effect on official GDP growth, and a positive impact of corruption on the size of the shadow economy can be found.

A simple mechanism for the efficient provision of public goods - experimental evidence

Abstract: The author reports on a series of experiments designed to investigate the factor of incentive mechanisms in the case of private provisions of public goods. In the Control treatment, there was no mechanism so that subjects faced strong free-riding incentives. In the so-called Falkinger mechanism treatment, the author implemented the Falkinger mechanism. The studies explored the impact of the mechanism in different economic environments. Results showed that the proposed incentive mechanism is very promising. Section I of the paper introduces the mechanism to be examined. Section II discusses the experimental design. Empirical results are provided in Section III, and Section IV interprets these results followed by a summary.

Nanometer-scale resolution of strain and interdiffusion in self-assembled InAs/GaAs quantum dots

Abstract: Tomographic nanometer-scale images of self-assembled InAs/GaAs quantum dots have been obtained from surface-sensitive x-ray diffraction. Based on the three-dimensional intensity mapping of selected regions in reciprocal space, the method yields the shape of the dots along with the lattice parameter distribution and the vertical interdiffusion profile on a subnanometer scale. The material composition is found to vary continuously from GaAs at the base of the dot to InAs at the top.

Relations Between Regularization and Diffusion Filtering

Abstract: Regularization may be regarded as diffusion filtering with an implicit time discretization where one single step is used. Thus, iterated regularization with small regularization parameters approximates a diffusion process. The goal of this paper is to analyse relations between noniterated and iterated regularization and diffusion filtering in image processing. In the linear regularization framework, we show that with iterated Tikhonov regularization noise can be better handled than with noniterated. In the nonlinear framework, two filtering strategies are considered: the total variation regularization technique and the diffusion filter technique of Perona and Malik. It is shown that the Perona-Malik equation decreases the total variation during its evolution. While noniterated and iterated total variation regularization is well-posed, one cannot expect to find a minimizing sequence which converges to a minimizer of the corresponding energy functional for the Perona–Malik filter. To overcome this shortcoming, a novel regularization technique of the Perona–Malik process is presented that allows to construct a weakly lower semi-continuous energy functional. In analogy to recently derived results for a well-posed class of regularized Perona–Malik filters, we introduce Lyapunov functionals and convergence results for regularization methods. Experiments on real-world images illustrate that iterated linear regularization performs better than noniterated, while no significant differences between noniterated and iterated total variation regularization have been observed.

The Increase of the Size of the Shadow Economy of 18 OECD Countries: Some Preliminary Explanations

Abstract: The latest empirical results of the size of the shadow economy in 18 OECD countries are presented, using the currency demand approach to calculate the shadow economy over time. The results indicate a strong increase in the size of the shadow economy, over the period 1960 to 1998 and for 15 of the 18 investigated OECD-countries the size of the shadow economy is more than 13% of the GNP for the year 1998. Also an analysis is given about the size of influences of major causes (direct and indirect tax burden and government regulation) on the shadow economy for Austria.

Tuning of Vertical and Lateral Correlations in Self-Organized PbSe/Pb 1-x Eu x Te Quantum Dot Superlattices

Abstract: The tuning of lateral and vertical correlations in self-organized PbSe/Pb 1-xEu xTe quantum dot superlattices by changes in the spacer thicknesses is demonstrated and shown to be due to finite size effects in the dot-dot interactions As a consequence, different dot arrangements such as vertically aligned dot columns or fcc stacking are obtained for a single material system without changes in growth conditions The different dot superstructures are shown to exhibit a different scaling behavior of the lateral versus vertical dot separation, as well as a different evolution of dot sizes and shapes

Immobilizing the Moving Parts of Voltage-Gated Ion Channels

Abstract: Voltage-gated ion channels have at least two classes of moving parts, voltage sensors that respond to changes in the transmembrane potential and gates that create or deny permeant ions access to the conduction pathway. To explore the coupling between voltage sensors and gates, we have systematically immobilized each using a bifunctional photoactivatable cross-linker, benzophenone-4-carboxamidocysteine methanethiosulfonate, that can be tethered to cysteines introduced into the channel protein by mutagenesis. To validate the method, we first tested it on the inactivation gate of the sodium channel. The benzophenone-labeled inactivation gate of the sodium channel can be trapped selectively either in an open or closed state by ultraviolet irradiation at either a hyperpolarized or depolarized voltage, respectively. To verify that ultraviolet light can immobilize S4 segments, we examined its relative effects on ionic and gating currents in Shaker potassium channels, labeled at residue 359 at the extracellular end of the S4 segment. As predicted by the tetrameric stoichiometry of these potassium channels, ultraviolet irradiation reduces ionic current by approximately the fourth power of the gating current reduction, suggesting little cooperativity between the movements of individual S4 segments. Photocross-linking occurs preferably at hyperpolarized voltages after labeling residue 359, suggesting that depolarization moves the benzophenone adduct out of a restricted environment. Immobilization of the S4 segment of the second domain of sodium channels prevents channels from opening. By contrast, photocross-linking the S4 segment of the fourth domain of the sodium channel has effects on both activation and inactivation. Our results indicate that specific voltage sensors of the sodium channel play unique roles in gating, and suggest that movement of one voltage sensor, the S4 segment of domain 4, is at least a two-step process, each step coupled to a different gate.

‘I have some faith and at the same time I don't believe’ — cognitive polyphasia and cultural change in India

Abstract: Issues of community and health are tightly linked to local cultures and to the system of traditional representations about health and illness. These systems, however, are rarely static, but are in constant flux through economic and technological developments — what is often called ‘modernisation’ — that entail new representations becoming part of everyday thinking. In this process the novel often plays the role of an icon of modernity in situations that evoke the idea of progress, while the traditional prevails in more static social structures such as the family. This co-existence of rarely compatible representations is called cognitive polyphasia. The present interview-study investigates the way 39 residents of the North-Indian city of Patna cope with contradictions implied by traditional and Western psychiatric notions of mental illness, their aetiology and treatment. It is shown that each of the two ways of thinking is situated and used in specific social settings. Some implications of cognitive polyphasia for community development are discussed. Copyright © 2000 John Wiley & Sons, Ltd.

Family and non-family succession in the Upper-Austrian farm sector.

Abstract: Using linked census data from 1980, 1985, and 1990 actual succession decisions of Upper-Austrian farm households are examined empirically Two types of succession are distinguished by inspecting the age of the farm operator and other household members in the consecutive census observations : “family succession” (succession by the farm operator’s child) and “non-family succession” (the farm is sold outside the family) Farm exits are considered as an additional category in the model Several characteristics of the farm and of the farm operator’s household are found to influence the succession decision significantly Model choice and specification issues are discussed

A new approach to convergence rate analysis of Tikhonov regularization for parameter identification in heat conduction

Abstract: In this paper we investigate the stability and convergence rates of the widely used output least-squares method with Tikhonov regularization for the identification of the conductivity distribution in a heat conduction system. Due to the rather restrictive source conditions and regularity assumptions on the nonlinear parameter-to-solution operator concerned, the existing Tikhonov regularization theory for nonlinear inverse problems is difficult to apply for the convergence rate analysis here. By introducing some new techniques, we are able to relax these regularity requirements and derive a much simpler and easily interpretable source condition but still achieve the same convergence rates as the standard Tikhonov regularization theory does.

Large piezoelectric effects in charged, heterogeneous fluoropolymer electrets

Abstract: Large piezoelectric d33 coefficients around 600 pC/N are found in corona-charged non-uniform electrets consisting of elastically “soft” (microporous polytetrafluoroethylene PTFE) and “stiff” (perfluorinated cyclobutene PFCB) polymer layers. The piezoelectric activity of the two-layer fluoropolymer stack exceeds the d33 coefficient of the ferroelectric ceramic lead zirconate titanate (PZT) by more than a factor of two and that of the ferroelectric polymer polyvinylidene fluoride (PVDF) by a factor of 20. Soft piezoelectric materials may become interesting for a large number of sensor and transducer applications, in areas such as security systems, medical diagnostics, and nondestructive testing.

3D Imaging of Individual Ion Channels in Live Cells at 40nm Resolution

Abstract: High affinity binding of fluorescence labeled hongotoxin (HgTX1-Cy5) to the potassium channel KV1.3 in T-lymphocyte cell membranes was utilized for imaging single ion channels optically, employing Single Dye Tracing (SDT). Binding sites were seen as single fluorescence peaks in cross-sections through the cell. Their number matched, at conditions of saturated binding, the number of sites expected from biochemical determination. By fitting the peaks to the point-spread-function, well approximated by a Gaussian distribution, resolution of channel positions to within ±40nm was obtained in all three dimensions. Within the focal plane (x-y plane) positional resolution is given by the accuracy of determining the peak position of the Gaussian. The positional resolution along the optical axis (z-direction) was obtained from the accuracy of estimating the position of minimum defocusing for a single molecule. For this, the width of the fluorescence peaks in consecutive images, taken at different degrees of defocusing, were shown to accurately match the theoretical prediction, yielding ∼40nm accuracy of finding the z-position of the labeled channels. This first visualization of individual membrane proteins in live cells by fluorescence labeled ligands with 40nm 3D positional resolution opens new perspectives for the study of cellular organization and processes at the molecular level.

On Landweber iteration for nonlinear ill-posed problems in Hilbert scales

Abstract: In this paper we derive convergence rates results for Landweber iteration in Hilbert scales in terms of the iteration index \(k\) for exact data and in terms of the noise level \(\delta\) for perturbed data. These results improve the one obtained recently for Landweber iteration for nonlinear ill-posed problems in Hilbert spaces. For numerical computations we have to approximate the nonlinear operator and the infinite-dimensional spaces by finite-dimensional ones. We also give a convergence analysis for this finite-dimensional approximation. The conditions needed to obtain the rates are illustrated for a nonlinear Hammerstein integral equation. Numerical results are presented confirming the theoretical ones.

A class of smoothers for saddle point problems

Abstract: In this paper smoothing properties are shown for a class of iterative methods for saddle point problems with smoothing rates of the order 1/m, where m is the number of smoothing steps. This generalizes recent results by Braess and Sarazin, who could prove this rates for methods where, in the context of the Stokes problem, the pressure correction equation is solved exactly, which is not needed here.

Haemodynamic changes during thoracoscopic surgery The effects of one‐lung ventilation compared with carbon dioxide insufflation

Abstract: We investigated the haemodynamic and respiratory effects of one-lung ventilation and carbon dioxide insufflation in 13 adult patients undergoing video-assisted thoracoscopy. Cardiorespiratory variables were determined during carbon dioxide insufflation at intrahemithoracic pressures of 5, 10 and 15 mmHg, and after 5 and 15 min of one-lung ventilation. Carbon dioxide insufflation was associated with a clear deterioration in circulatory function. The cardiac index decreased subsequent to increasing intrathoracic pressures. The mean cardiac index (SD) at pressures of 10 and 15 mmHg was 1.86 (0.39) and 1.52 (0.46), respectively, and may be compared with the reduced venous return consistent with tension pneumothorax. One-lung ventilation did not affect haemodynamic variables but reduced arterial oxygenation indices (PaO2/FIO2) from 424.29 (160.79) after induction of anaesthesia, to 207.72 (125.50) after 5 min and 172.04 (72.03) after 15 min of one-lung ventilation, respectively. The oxygenation index was not influenced by intrahemithoracic carbon dioxide insufflation. One-lung ventilation via a double-lumen endobronchial tube is safe and convenient for video-assisted thoracoscopic surgery. It has no further consequences on haemodynamic variables, whereas the compression of the lung by carbon dioxide insufflation may cause circulatory dysfunction.

A Simple Mechanism for the Efficient Provision of Public Goods - Experimental Evidence

Abstract: This paper presents an experimental examination of the Falkinger (1996) mechanism for overcoming the free-rider problem. The basic idea of the mechanism is that deviations from the mean contribution to the public good are taxed and subsidized. The mechanism has attractive properties because (i) it induces higher contributions to the public good and can implement an efficient level of contributions as a Nash equilibrium, (ii) the government budget is always balanced irrespective of the level of individual contributions, (iii) it is simple and policy makers need only little information to implement the mechanism. To examine the empirical properties of the mechanism we conducted a large series of experiments. It turns out that the introduction of the mechanism generates immediate and large efficiency gains. This result is robust throughout many different experimental settings. Moreover, in the presence of the mechanism the Nash equilibrium is a rather good predictor of behavior.

A Reissner-Mindlin-type plate theory including the direct piezoelectric and the pyroelectric effect

Abstract: This paper is concerned with flexural vibrations of composite plates, where piezoelastic layers are used to generate distributed actuation or to perform distributed sensing of strains in the plate. Special emphasis is given to the coupling between mechanical, electrical and thermal fields due to the direct piezoelectric effect and the pyroelectric effect. Moderately thick plates are considered, where the influence of shear and rotatory inertia is taken into account according to the kinematic approximations introduced by Mindlin. An equivalent single-layer theory is thus derived for the composite plates. It is shown that coupling can be taken into account by means of effective stiffness parameters and an effective thermal loading. Polygonal plates with simply supported edges are treated in some detail, where quasi-static thermal bending as well as free, forced and actuated vibrations are studied.

Lattice parameter of Si 1 − x − y Ge x C y alloys

Abstract: The introduction of carbon into silicon-germanium--based heterostructures offers increased flexibility in tailoring their strain state and electronic properties. Still, however, fundamental physical properties such as the lattice parameter and the elastic properties of ${\mathrm{Si}}_{1\ensuremath{-}x\ensuremath{-}y}{\mathrm{Ge}}_{x}{\mathrm{C}}_{y}$ random alloys are not precisely known. In this paper, we present a quantitative study of the effect of carbon on the lattice parameter of ${\mathrm{Si}}_{1\ensuremath{-}x\ensuremath{-}y}{\mathrm{Ge}}_{x}{\mathrm{C}}_{y}$ alloys in the technologically relevant range of Ge and C compositions. A strong deviation from Vegard's rule is experimentally and theoretically derived. The influence of the correlation between Ge and C on the lattice parameter is discussed. The results allow us to establish the compensation ratio $\ensuremath{ u}$ of Ge to C concentrations (where the ${\mathrm{Si}}_{1\ensuremath{-}x\ensuremath{-}y}{\mathrm{Ge}}_{x}{\mathrm{C}}_{y}$ epilayer is lattice matched to Si), for which we find a value of $\ensuremath{ u}=12.$

A wireless pressure-measurement system using a SAW hybrid sensor

Abstract: A pressure-measurement system based on surface-acoustic-wave (SAW) sensors is presented in this paper. Since SAW sensors are powered by the energy of the RF field, no battery is required, which is a major drawback of conventional microcontroller-based telemetry systems. A successful combination of a SAW reflective delay line with a high-Q capacitive pressure sensor is shown, With a new way of matching the sensor impedance to the SAW reflector impedance, both a high signal-to-noise ratio and a high signal dynamic are achieved, which supports accurate signal evaluation. As an example of realization, the prototype of the pressure sensor unit is presented.

Allowing For Household Preferences In Emission Trading? A Contribution To The Climate Policy Debate

Abstract: In the context of emission trading it seems to be taken as given that people's preferences can be ignored with respect to the whole process of fixing emission targets and allocating emission permits to polluters. With this paper we want to reopen the debate on how citizens can be involved in this process. We try to show how citizen preferences can be included in the process of pollution control through emission trading. We propose an emission trading system where all emission permits are initially allocated to households who are then allowed to sell them in the permit market or to withhold (at least some of) them in order to reduce total pollution. This proposal tries to overcome the fundamental disadvantage of traditional permit systems which neglect consumer preferences by solely distributing emission permits to producers / polluters. In our system the property right to nature is re-allocated to the households who obtain the opportunity of reducing actual emissions according to their personal preferences by withholding a part or all of the emission permits allotted to them. Such a change in environmental policy would mark a return to the traditional principles of consumer sovereignty by involving households (at least partially) in the social abatement decision process instead of excluding them. Another advantage of admitting households to the TEP market as sellers or buyers of permits is that this increases the number of agents in the permit market and thus significantly reduces the possibilities of strategic market manipulations.

Discovering Next Generation Tourism Information Systems: A Tour on TIScover

Abstract: Information technology has been playing a fundamental role in the tourism industry for a long time. The Internet particularly is increasingly emerging as a perfect platform to bring tourism products direct to the customer. Web-based tourism information systems, however, are required not only to offer online brochures but also to provide both value and service. The Austrian tourism information system, TIScover, meets this challenge by focusing on three crucial points. First, high-quality access is provided, both by supporting e-commerce transactions and by allowing access to the system via the World Wide Web, info kiosks, and cellular phones. Second, the content is of a high quality that is achieved by enabling tourism information providers to maintain their products directly, as well as by integrating external tourism information sources. Finally, the system is designed in such a way that it is easy to customize. This facilitates employment of the system by the various kinds of tourism information provide...