8,987 research outputs found

    Risk attitude, beliefs, and information in a corruption game: An experimental analysis

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    For our experiment on corruption we designed a coordination game to model the influence of risk attitudes, beliefs, and information on behavioral choices and determined the equilibria. We observed that the participants' risk attitudes failed to explain their choices between corrupt and non-corrupt behavior. Instead, beliefs appeared to be a better predictor of whether or not they would opt for the corrupt alternative. Furthermore, varying the quantity of information available to players (modeled by changing the degree of uncertainty) provided additional insight into the players' propensity to engage in corrupt behavior. The experimental results show that a higher degree of uncertainty in the informational setting reduces corruption. --Corruption,game theory,experiment,risk attitude,beliefs

    Nonautonomous Spectral Submanifolds for Model Reduction of Nonlinear Mechanical Systems under Parametric Resonance

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    We use the recent theory of Spectral Submanifolds (SSM) for model reduction of nonlinear mechanical systems subject to parametric excitations. Specifically, we develop expressions for higher-order nonautonomous terms in the parameterization of SSMs and their reduced dynamics. We provide these results both for general first-order as well as second-order mechanical systems under periodic and quasiperiodic excitation using a multi-index based approach, thereby optimizing memory requirements and the computational procedure. We further provide theoretical results that simplify the SSM parametrization for general second-order dynamical systems. More practically, we show how the reduced dynamics on the SSM can be used to extract the resonance tongues and the forced response around the principal resonances in parametrically excited systems. In the case of two-dimensional SSMs, we formulate explicit expressions for computing the steady-state response as the zero-level set of a two-dimensional function for systems that are subject to external as well as parametric excitation. This allows us to parallelize the computation of the forced response over the range of excitation frequencies. We demonstrate our results on several examples of varying complexity, including finite-element type examples of mechanical systems. Furthermore, we provide an open-source implementation of all these results in the software package SSMTool

    Oceanic three-dimensional Lagrangian Coherent Structures: A study of a mesoscale eddy in the Benguela ocean region

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    We study three dimensional oceanic Lagrangian Coherent Structures (LCSs) in the Benguela region, as obtained from an output of the ROMS model. To do that we first compute Finite-Size Lyapunov exponent (FSLE) fields in the region volume, characterizing mesoscale stirring and mixing. Average FSLE values show a general decreasing trend with depth, but there is a local maximum at about 100 m depth. LCSs are extracted as ridges of the calculated FSLE fields. They present a "curtain-like" geometry in which the strongest attracting and repelling structures appear as quasivertical surfaces. LCSs around a particular cyclonic eddy, pinched off from the upwelling front are also calculated. The LCSs are confirmed to provide pathways and barriers to transport in and out of the eddy

    Perfectly localized Majorana corner modes in fermionic lattices

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    Focusing on examples of Majorana zero modes on the corners of a two-dimensional lattice, we introduce a method to find parameter regions where the Majorana modes are perfectly localized on a single site. Such a limit allows us to study the dimerization structure of the sparse bulk Hamiltonian that results in the higher-order topology of the system. Furthermore, such limits typically provide an analytical understanding of the system energy scales. Based on the dimerization structure we extract from the two-dimensional model, we identify a more general stacking procedure to construct Majorana zero modes in arbitrary corners of a dd-dimensional hypercube, which we demonstrate explicitly in d≀3d\leq3.Comment: 12 pages, 12 figure

    Marketing im liberalisierten Strommarkt

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    Im Fokus dieser Arbeit steht der Wandlungsprozess in Österreichs Stromwirtschaft aus Sicht des Marketings fĂŒr Privatkunden im Gefolge der Liberalisierung und Privatisierung des ehemals monopolistisch organisierten Sektors. Die Arbeit liefert die Ergebnisse einer umfassenden empirischen Untersuchung, die durch einen innovativen Forschungszutritt geprĂ€gt ist. Es werden sowohl qualitative als auch quantitative Methoden der empirischen Sozialforschung kombiniert, deren komplementĂ€re Funktion damit eindrucksvoll belegt wird. Zielsetzung ist, die Gestaltung des Produktes Strom an der PrĂ€ferenz der nachfragenden Konsumenten zu orientieren und mit Hilfe der Conjoint-Analyse die Produktgestaltung zu optimieren. Des Weiteren wird ein Messinstrument zur Erfassung des Involvements mit Strom entwickelt. Dem Anspruch einer realtheoretischen Forschung folgend werden zahlreiche Handlungsempfehlungen aufgezeigt

    Fusion-Activated Ca2+ Entry: An “Active Zone” of Elevated Ca2+ during the Postfusion Stage of Lamellar Body Exocytosis in Rat Type II Pneumocytes

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    Background Ca2+ is essential for vesicle fusion with the plasma membrane in virtually all types of regulated exocytoses. However, in contrast to the well-known effects of a high cytoplasmic Ca2+ concentration ([Ca2+]c) in the prefusion phase, the occurrence and significance of Ca2+ signals in the postfusion phase have not been described before. Methodology/Principal Findings We studied isolated rat alveolar type II cells using previously developed imaging techniques. These cells release pulmonary surfactant, a complex of lipids and proteins, from secretory vesicles (lamellar bodies) in an exceptionally slow, Ca2+- and actin-dependent process. Measurements of fusion pore formation by darkfield scattered light intensity decrease or FM 1-43 fluorescence intensity increase were combined with analysis of [Ca2+]c by ratiometric Fura-2 or Fluo-4 fluorescence measurements. We found that the majority of single lamellar body fusion events were followed by a transient (t1/2 of decay = 3.2 s) rise of localized [Ca2+]c originating at the site of lamellar body fusion. [Ca2+]c increase followed with a delay of ∌0.2–0.5 s (method-dependent) and in the majority of cases this signal propagated throughout the cell (at ∌10 ”m/s). Removal of Ca2+ from, or addition of Ni2+ to the extracellular solution, strongly inhibited these [Ca2+]c transients, whereas Ca2+ store depletion with thapsigargin had no effect. Actin-GFP fluorescence around fused LBs increased several seconds after the rise of [Ca2+]c. Both effects were reduced by the non-specific Ca2+ channel blocker SKF96365. Conclusions/Significance Fusion-activated Ca2+ entry (FACE) is a new mechanism that leads to [Ca2+]c transients at the site of vesicle fusion. Substantial evidence from this and previous studies indicates that fusion-activated Ca2+ entry enhances localized surfactant release from type II cells, but it may also play a role for compensatory endocytosis and other cellular functions
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