952 research outputs found

    Exclusive vs Overlapping Viewers in Media Markets

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    This paper investigates competition for advertisers in media markets when viewers can subscribe to multiple channels. A central feature of the model is that channels are monopolists in selling advertising opportunities toward their exclusive viewers, but they can only obtain a competitive price for advertising opportunities to multi-homing viewers. Strategic incentives of firms in this setting are different than those in former models of media markets. If viewers can only watch one channel, then firms compete for marginal consumers by reducing the amount of advertising on their channels. In our model, channels have an incentive to increase levels of advertising, in order to reduce the overlap in viewership. We take an account of the differences between the predictions of the two types of models and find that our model is more consistent with recent developments in broadcasting markets. We also show that if channels can charge subscription fees on viewers, then symmetric firms can end up in an asymmetric equilibrium in which one collects all or most of its revenues from advertisers, while the other channel collects most of its revenues via viewer fees

    Investments in Social Ties, Risk Sharing and Inequality

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    This paper investigates stable and efficient networks in the context of risk-sharing, when it is costly to establish and maintain relationships that facilitate risk-sharing. We find a novel trade-off between efficiency and equality. The most stable effic

    Between pragmatism and predictability: temporariness in international law

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    One of the key functions or purposes of international law (and law in general for that matter) is to provide long-term stability and legal certainty. Yet, international legal rules may also function as tools to deal with non-permanent or constantly changing issues, and rather than stable, international law may have to be flexible or adaptive. Prima facie, one could think of two main types of temporary aspects relevant from the perspective of international law. First, the nature of the object addressed by international law or the ‘problem’ that international law aims to address may be inherently temporary (temporary objects). Second, a subject of international law may be created for a specific period of time, after the elapse of which this entity ceases to exist (temporary subjects). These types of temporariness raise several questions from the perspective of international law, which are hardly addressed from a more conceptual perspective. This volume of the Netherlands Yearbook of International Law aims to do exactly that by asking the question of how international law reacts to various types of temporary issues. Put differently, where does international law stand on the continuum of predictability and pragmatism when it comes to temporary issues or institutions

    MECHANICAL MODEL FOR HUMAN BALANCING ON ROLLING BALANCE BOARD

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    A two-degree-of-freedom mechanical model was developed to analyze human balancing on rolling balance board in the frontal plane. The human nervous system is modeled as a proportionalderivative controller with constant feedback delay. The radius R of the wheels and the board distance h measured from the center of the wheel are adjustable parameters. Simulation results using the mechanical model were compared with real balancing trials recorded by an OptiTrack motion capture system. The goal of the paper is to investigate whether the two-degree-of-freedom model is accurate enough to model the balancing task and to introduce a stabilometry parameter in order to characterize balancing skill in case of different set of R and h. The conclusion is that the angle of the upper body and the angle of the head also play an important role in the balancing process therefore a three- or four-degree-of-freedom model is more appropriate

    Makrogerinctelen-együttesek tér- és időbeli változásai a hansági Nyirkai-Hany élőhely-rekonstrukciós területen

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    Vizsgálatainkat a 2001-2002-ben kialakított Nyirkai–Hany vizes élőhely-rekonstrukciós területen végeztük. Tíz helyszínen 2007 áprilisától 2008 májusáig havonta gyűjtöttünk bentosz és metafiton mintákat, hogy megvizsgáljuk a terület makrogerinctelen faunáját és együtteseit, valamint ezek szezonális és térbeli eltéréseit. A területen gyűjtött 110 fajból 79-et elsőként sikerült kimutatnunk az élőhely-rekonstrukcióról, emellett két, a hazai faunára új árvaszúnyog faj is előkerült. Az egyes mintavételi helyszínek makrogerinctelen faunájukat tekintve leginkább az egyes területeken belül hasonlítottak egymásra. Fajkészletében a három terület nem tért el számottevően, ugyanakkor a kimutatott fajok számában különbségek adódtak

    Causal evidence of the involvement of the right occipital face area in face-identity acquisition

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    There is growing evidence that the occipital face area (OFA), originally thought to be involved in the construction of a low-level representation of the physical features of a face, is also taking part in higher-level face processing. To test whether the OFA is causally involved in the learning of novel face identities, we have used transcranial magnetic stimulation (TMS) together with a sequential sorting – face matching paradigm (Andrews et al. 2015). First, participants sorted images of two unknown persons during the initial learning phase while either their right OFA or the Vertex was stimulated using TMS. In the subsequent test phase, we measured the participants’ face matching performance for novel images of the previously trained identities and for two novel identities. We found that face-matching performance accuracy was higher for the trained as compared to the novel identities in the vertex control group, suggesting that the sorting task led to incidental learning of the identities involved. However, no such difference was observed between trained and novel identities in the rOFA stimulation group. Our results support the hypothesis that the role of the rOFA is not limited to the processing of low-level physical features, but it has a significant causal role in face identity encoding and in the formation of identity-specific memory-traces

    Multicomponent flow on curved surfaces : A vielbein lattice Boltzmann approach

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    We develop and implement a novel finite difference lattice Boltzmann scheme to study multicomponent flows on curved surfaces, coupling the continuity and Navier-Stokes equations with the Cahn-Hilliard equation to track the evolution of the binary fluid interfaces. The standard lattice Boltzmann method relies on regular Cartesian grids, which makes it generally unsuitable to study flow problems on curved surfaces. To alleviate this limitation, we use a vielbein formalism to write down the Boltzmann equation on an arbitrary geometry, and solve the evolution of the fluid distribution functions using a finite difference method. Focussing on the torus geometry as an example of a curved surface, we demonstrate drift motions of fluid droplets and stripes embedded on the surface of such geometries. Interestingly, they migrate in opposite directions: fluid droplets to the outer side while fluid stripes to the inner side of the torus. For the latter we demonstrate that the global minimum configuration is unique for small stripe widths, but it becomes bistable for large stripe widths. Our simulations are also in agreement with analytical predictions for the Laplace pressure of the fluid stripes, and their damped oscillatory motion as they approach equilibrium configurations, capturing the corresponding decay timescale and oscillation frequency. Finally, we simulate the coarsening dynamics of phase separating binary fluids in the hydrodynamics and diffusive regimes for tori of various shapes, and compare the results against those for a flat two-dimensional surface. Our finite difference lattice Boltzmann scheme can be extended to other surfaces and coupled to other dynamical equations, opening up a vast range of applications involving complex flows on curved geometries
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