Bruno Frey, Frauen und Kinder zuerst, In: Die Weltwoche, 06/09, p. 21, 1 January 2009. (Newspaper Article)
Wie verhalten sich Menschen in Extremsituationen? Am Untergang der «Titanic» zeigt sich: Selbst in der Katastrophe funktioniert der Mensch als soziales Wesen. Amerikaner überlebten überproportional oft. |
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Klaas Enno Stephan, K J Friston, Functional connectivity, In: Encyclopedia of Neuroscience, Elsevier, New York, p. 391 - 397, 2009. (Book Chapter)
Functional neuroimaging techniques are used widely in cognitive neuroscience to investigate aspects of functional specialization and functional integration in the human brain. Functional integration can be characterized in two ways – functional connectivity and effective connectivity. Whereas functional connectivity describes statistical dependencies between data, effective connectivity rests on a mechanistic model of the causal effects that generated the data. This article reviews the conceptual and methodological bases of established techniques for characterizing functional and effective connectivity using electrophysiological and functional neuroimaging data. |
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Klaas Enno Stephan, L Kasper, K H Brodersen, C Mathys, Funktionelle und effektive Konnektivität, Klinische Neurophysiologie, Vol. 40 (4), 2009. (Journal Article)
Zusammenfassung
Neurophysiologische und bildgebende Verfahren zur Messung von Hirnaktivität, wie fMRI oder EEG, werden in den Neurowissenschaften eingesetzt, um Prozesse funktioneller Spezialisierung und funktioneller Integration im menschlichen Gehirn zu untersuchen. Funktionelle Integration kann auf zwei verschiedene Arten beschrieben werden: funktionelle Konnektivität und effektive Konnektivität. Während die funktionelle Konnektivität lediglich statistische Abhängigkeiten zwischen Zeitreihen beschreibt, erfordert das Konzept der effektiven Konnektivität ein mechanistisches Modell der kausalen Effekte, die den beobachteten Daten zu Grunde liegen. Dieser Artikel fasst die konzeptionellen und methodischen Grundlagen moderner Techniken für die Analyse funktioneller und effektiver Konnektivität auf der Basis von fMRI und elektrophysiologischen Daten zusammen. Ein besonderer Schwerpunkt liegt dabei auf dem Dynamic Causal Modelling (DCM), einem neuen Verfahren zur Analyse nichtlinearer neuronaler Systeme. Diese Methode besitzt ein vielversprechendes Potenzial für klinische Anwendungen, z. B. zur Entschlüsselung pathophysiologischer Mechanismen bei Hirnerkrankungen und zur Etablierung neurophysiologisch fundierter diagnostischer Klassifikationen.
Abstract
Neurophysiological and imaging procedures to measure brain activity, such as fMRI or EEG, are employed in neuroscience to investigate processes of functional specialisation and functional integration in the human brain. Functioal integration can be described in two distinct ways: functional connectivity and effective connectivity. Whereas functional connectivity merely describes the statistical dependence between two time series, the concept of effective connectivity requires a mechanistic model of the causative effects upon which the data to be observed are based. This article summarises the conceptual and methodological principles of modern techniques for the analysis of functional and effective connectivity on the basis of fMRI and electrophysiological data. Particular emphasis is placed on dynamic causal modelling (DCM), a new procedure for the analysis of non-linear neuronal systems. This method has a highly promising potential for clinical applications, e. g., for decoding pathological mechanisms in brain diseases and for the establishment of neurologically valid diagnostic classifications. |
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Alexander S Preker, Global marketplace for private health insurance: strength in numbers, World Bank, Washington, DC, 2009. (Book/Research Monograph)
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Christian Ruff, F Blankenburg, O Bjoertomt, S Bestmann, N Weiskopf, J Driver, Hemispheric differences in frontal and parietal influences on human occipital cortex: direct confirmation with concurrent TMS-fMRI, Journal of Cognitive Neuroscience, Vol. 21 (6), 2009. (Journal Article)
We used concurrent TMS-fMRI to test directly for hemispheric differences in causal influences of the right or left fronto-parietal cortex on activity (BOLD signal) in the human occipital cortex. Clinical data and some behavioral TMS studies have been taken to suggest right-hemisphere specialization for top-down modulation of vision in humans, based on deficits such as spatial neglect or extinction in lesioned patients, or findings that TMS to right (vs. left) fronto-parietal structures can elicit stronger effects on visual performance. But prior to the recent advent of concurrent TMS and neuroimaging, it was not possible to directly examine the causal impact of one (stimulated) brain region upon others in humans. Here we stimulated the frontal or intraparietal cortex in the left or right hemisphere with TMS, inside an MR scanner, while measuring with fMRI any resulting BOLD signal changes in visual areas V1-V4 and V5/MT+. For both frontal and parietal stimulation, we found clear differences between effects of right- versus left-hemisphere TMS on activity in the visual cortex, with all differences significant in direct statistical comparisons. Frontal TMS over either hemisphere elicited similar BOLD decreases for central visual field representations in V1-V4, but only right frontal TMS led to BOLD increases for peripheral field representations in these regions. Hemispheric differences for effects of parietal TMS were even more marked: Right parietal TMS led to strong BOLD changes in V1-V4 and V5/MT+, but left parietal TMS did not. These data directly confirm that the human frontal and parietal cortex show right-hemisphere specialization for causal influences on the visual cortex. |
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Bruno Frey, How can business cope with terrorism?, Journal of Policy Modeling, Vol. 31 (5), 2009. (Journal Article)
What can business do to cope more successfully with terrorism?” The policy against terrorism available to business is a neglected issue in the scholarly literature especially in so far as individual firms rather than the business sector as a whole are concerned. Two sets of proposals are advanced, based on an economic analysis of terrorism. The first set discusses possibilities to reduce terrorists’ incentives to attack business premises; the second part outlines proposals designed to minimize the costs to businesses once a terrorist attack has taken place, hence reducing the impact. |
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Rafael Lalive, Josef Zweimüller, How does parental leave affect fertility and return to work? Evidence from two natural experiments, Quarterly Journal of Economics, Vol. 124 (3), 2009. (Journal Article)
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N Weiskopf, O Josephs, Christian Ruff, F Blankenburg, E Featherstone, A Thomas, S Bestmann, J Driver, R Deichmann, Image artifacts in concurrent transcranial magnetic stimulation (TMS) and fMRI caused by leakage currents: Modeling and compensation, Journal of Magnetic Resonance Imaging, Vol. 29 (5), 2009. (Journal Article)
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Beat Hotz-Hart, Les relations entreprises-recherche publique en Suisse dans le contexte de globalisation, In: Recherche et enseignement supérieur face à l’internalisation: France, Suisse et Union européenne, Presses Polytechniques et Universitaires Romandes, Lausanne, p. 371 - 393, 2009. (Book Chapter)
Dans un contexte en transformation, les systèmes nationaux de recherche et d’enseignement supérieur rencontrent des défis semblables : avènement de la société ou de l’économie du savoir, globalisation scientifique, compétitivité, évaluation et, enfin, acceptation sociale des sciences et des techniques. Les Etats (mais aussi les chercheurs) répondent toutefois à ces défis de façon différente, en fonction de leur tradition, de leurs spécificités ou de leur marge de manoeuvre. La dimension internationale de la recherche et de l’enseignement supérieur est depuis longtemps un objet d’étude assez controversé et fait actuellement toujours problème : depuis la Seconde Guerre mondiale environ, l’internationalisation a certes été renforcée sous l’impulsion de divers programmes politiques et scientifiques et a débouché sur une redéfinition du clivage interne/externe, mais on observe aussi de nombreux discours politiques et scientifiques qui instrumentalisent la notion d’internationalisation à différentes fins. Des études de cas fouillées prises principalement dans les deux systèmes français et suisse de recherche et d’enseignement supérieur, placés dans une perspective comparative internationale, permettent de documenter le statut et le poids du phénomène d’internationalisation (Espace européen de la recherche, processus de Bologne, rankings, localisation des activités scientifiques, attitudes face à la recherche, sciences de la vie, nanotechnologies, open science, propriété intellectuelle, relations universités-entreprises).
Introduction - Approches et usages de l’internationalisation dans les systèmes de recherche et d’enseignement supérieur - Rôle de l’internationalisation dans la construction des systèmes de recherche et d’enseignement supérieur - La recherche européenne et les enjeux des nouvelles sciences dominantes - L’Union européenne et le principe de subsidiarité dans le domaine de l’éducation - L’internationalisation de la recherche face aux outils «ouverts» de la collaboration scientifique de masse - Les usages helvétiques des enjeux internationaux dans le processus de création de la politique de la recherche (1945-1970) - Mesure de l’internationalisation: le développement des indicateurs et leurs effets - La recherche européenne: en quête de légitimité et d’efficacité - Rankings internationaux de la recherche: des usages variés dans la politique scientifique - Discours politique et intégration internationale de la communauté scientifique en Suisse - La coordination de la politique du savoir et de l’innovation: une analyse comparative - Diffusion internationale de recettes de politiques publiques ou de normes en matière de recherche et d’enseignement supérieur - Internationalisation des systèmes d’enseignement supérieur: convergence et différenciation - Le processus de Bologne comme contournement de l’UE: les dynamiques paradoxales de construction de l’Espace européen d’enseignement supérieur - L’international comme ressource cognitive et symbolique: changements dans l’instrumentation de la recherche et de l’enseignement supérieur en Suisse - Influence des logiques multi-niveaux sur les dynamiques nationales et régionales de la recherche et de l’enseignement supérieur - La gouvernance multi-niveaux de la recherche et de l’innovation dans les régions françaises - La territorialisation comme contrepoint à l’internationalisation des activités scientifiques - Le financement de projets de recherche en Europe: entre convergences et traditions nationales - Circulation internationale des savoirs et production d’innovations techno-scientifiques - Internationalisation et régimes de propriété dans les sciences de la vie - Emergence des nanotechnologies: vers un nouveau «modèle industriel»? - Les relations entreprises-recherche publique en Suisse dans le contexte de globalisation - Liste des auteur-e-s |
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S Boretius, L Kasper, R Tammer, T Michaelis, J Frahm, MRI of cellular layers in mouse brain in vivo, NeuroImage, Vol. 47 (4), 2009. (Journal Article)
Noninvasive imaging of the brain of animal models demands the detection of increasingly smaller structures by in vivo MRI. The purpose of this work was to elucidate the spatial resolution and structural contrast that can be obtained for studying the brain of C57BL/6J mice by optimized T2-weighted fast spin-echo MRI at 9.4 T. As a prerequisite for high-resolution imaging in vivo, motion artifacts were abolished by combining volatile anesthetics and positive pressure ventilation with a specially designed animal bed for fixation. Multiple substructures in the cortex, olfactory bulb, hippocampus, and cerebellum were resolved at 30 to 40 microm in-plane resolution and 200 to 300 microm section thickness as well as for relatively long echo times of 65 to 82 ms. In particular, the approach resulted in the differentiation of up to five cortical layers. In the olfactory bulb the images unraveled the mitral cell layer which has a thickness of mostly single cells. In the hippocampus at least five substructures could be separated. The molecular layer, Purkinje layer, and granular layer of the cerebellum could be clearly differentiated from the white matter. In conclusion, even without the use of a contrast agent, suitable adjustments of a widely available T2-weighted MRI sequence at high field allow for structural MRI of living mice at near single-cell layer resolution. |
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Rafael Lalive, Armin Schmutzler, Mehr Effizienz durch Wettbewerb im SPNV: Illusion oder Wirklichkeit?, In: Die Zukunft des öffentlichen Personennahverkehrs, Lexxion, Berlin, p. 165 - 178, 2009. (Book Chapter)
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K Beck, Mehr pragmatische Ansätze und weniger Politik, Clinicum: das Fachmagazin mit Format für Spital- und Heim- Management, Vol. 2009 (Report), 2009. (Journal Article)
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Lorenz Götte, Armin Schmutzler, Merger policy: what can we learn from experiments?, In: Experiments and Competition Policy, Cambridge University Press, Cambridge, p. 185 - 216, 2009. (Book Chapter)
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Pavlo R Blavatskyy, Ganna Pogrebna, Myopic loss aversion revisited, Economics Letters, Vol. 104 (1), 2009. (Journal Article)
In this paper we reexamine several experimental papers on myopic loss aversion by analyzing individual rather than aggregate choice patterns. We find that the behavior of the majority of subjects is inconsistent with the hypothesis of myopic loss aversion. |
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Susanne Neckermann, Of awards in companies - an econometric assessment of honor and recognition as incentives, University of Zurich, Faculty of Economics, Business Administration and Information Technology, 2009. (Dissertation)
Awards are increasingly popular in the corporate sector to motivate employees. Managers consider innovative human resource practices, such as awards, to be essential to enhance firm competitiveness. The prevalence and popularity of awards in the corporate sector suggest that awards fulfill important functions in principal‐agent relationships. This is contrasted with the paucity of academic research targeted at recognition programs.
This thesis provides an extensive discussion of awards and demonstrates their effect on employee performance. Chapters 2 and 3 lay the theoretical foundation for why awards may motivate and discuss their relationship with other incentive instruments. Additionally, some insights into practitioners' perceptions of the topic are presented. Chapters 4 to 6 provide the empirical evidence. The field experiment presented in chapter 4 shows that productivity in a data entry job is significantly higher in workgroups where the two best employees can get an award in addition to the fixed wage that is identical for all workgroups. Chapter 5 reports the results of an econometric study using data on awards and employee performance from the call center of a large international bank. It can be shown that the performance of award winners is significantly higher than that of nonrecipients one month after the award is handed out. Chapter 6 sheds some light into what award features drive this effect by reporting the results of a vignette study with researchers at a research laboratory. The findings suggest that the publicity associated with winning an award is a major motivation force that drives people to aspire an award. Finally, Chapter 7 concludes. |
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Ernst Fehr, On the economics and biology of trust, Journal of the European Economic Association, Vol. 7 (2-3), 2009. (Journal Article)
In recent years, many social scientists have claimed that trust plays an important role in economic and social transactions. Despite its proposed importance, the measurement and the definition of trust seem to be not fully settled, and the identification of the exact role of trust in economic interactions has proven to be elusive. It is still not clear whether trust is just an epiphenomenon of good institutions or whether it plays an independent causal role capable of shaping important aggregate economic outcomes. In this paper, I rely on a behavioral definition of trust that enables us to relate it to economic primitives such as preferences and beliefs. I review strong biological and behavioral evidence indicating that trusting is not just a special case of risk-taking, but based on important forms of social preferences such as betrayal aversion. Behaviorally defined trust also opens the door for understanding national and ethnic trust differences in terms of differences in preferences and beliefs, and it suggests ways to examine and interpret a causal role of trust. |
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Jan Boone, Jacob Goeree, Optimal privatisation using qualifying auctions, Economic Journal, Vol. 119 (534), 2009. (Journal Article)
This article explores use of auctions for privatising public assets. In our model, a single ‘insider’ bidder possesses information about the asset's common value. Bidders are privately informed about their costs of exploiting the asset. Due to the insider's presence, uninformed bidders face a strong winner's curse in standard auctions. We show that the optimal mechanism discriminates against the informationally advantaged bidder. It can be implemented via a two-stage ‘qualifying auction’. In the first stage, non-binding bids are submitted to determine who enters the second stage, which consists of a standard second-price auction augmented with a reserve price. |
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A C Marreiros, S J Kiebel, Jean Daunizeau, L M Harrison, K J Friston, Population dynamics under the Laplace assumption, NeuroImage, Vol. 44 (3), 2009. (Journal Article)
In this paper, we describe a generic approach to modelling dynamics in neuronal populations. This approach models a full density on the states of neuronal populations but finesses this high-dimensional problem by re-formulating density dynamics in terms of ordinary differential equations on the sufficient statistics of the densities considered (c.f., the method of moments). The particular form for the population density we adopt is a Gaussian density (c.f., the Laplace assumption). This means population dynamics are described by equations governing the evolution of the population's mean and covariance. We derive these equations from the Fokker-Planck formalism and illustrate their application to a conductance-based model of neuronal exchanges. One interesting aspect of this formulation is that we can uncouple the mean and covariance to furnish a neural-mass model, which rests only on the populations mean. This enables us to compare equivalent mean-field and neural-mass models of the same populations and evaluate, quantitatively, the contribution of population variance to the expected dynamics. The mean-field model presented here will form the basis of a dynamic causal model of observed electromagnetic signals in future work. |
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Stephanie Berner, Karolin Leukert, Peter Zweifel, Präferenzen für Krankenversicherung in Deutschland und den Niederlanden: Ein Zweiländervergleich, In: Experimentelle Wirtschaftsforschung, Mohr Siebeck, Tübingen, p. 125 - 145, 2009. (Book Chapter)
The annual Ottobeuren Seminar on Economics brings together experts on a previously chosen subject. The special purpose of these seminars is to present new theoretical approaches as well as new empirical findings and to discuss the political-economic conclusions with them. This volume contains the papers and discussions of the 38th Ottobeuren Seminar on Economics dealing with the subject of experimental economics. It presents several experiments, some of whose results clearly contradict the predictions of traditional economics and thus provide important incentives for a reformulation of the theoretical approaches. |
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Harry Niederau, Peter Zweifel, Quasi risk-neutral pricing in insurance, ASTIN Bulletin, Vol. 39 (1), 2009. (Journal Article)
This contribution shows that for certain classes of insurance risks, pricing can be based on expected values under a probability measure P* amounting to quasi risk-neutral pricing. This probability measure is unique and optimal in the sense of minimizing the relative entropy with respect to the actuarial probability measure P, which is a common approach in the case of incomplete markets. After expounding the key elements of this theory, an application to a set of industrial property risks is developed, assuming that the severity of losses can be modeled by 'Swiss Re Exposure Curves', as discussed by Bernegger (1997). These curves belong to a parametric family of distribution functions commonly used by pricing actuaries. The quasi risk-neutral pricing approach not only yields risk exposure specific premiums but also Risk Adjusted Capital (RAC) values on the very same level of granularity. By way of contrast, the conventional determination of RAC is typically considered on a portfolio level only. |
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