1,155 research outputs found

    Relative Resolution: A Multipole Approximation at Appropriate Distances

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    Recently, we introduced Relative Resolution as a hybrid formalism for fluid mixtures [1]. The essence of this approach is that it switches molecular resolution in terms or relative separation: While nearest neighbors are characterized by a detailed fine-grained model, other neighbors are characterized by a simplified coarse-grained model. Once the two models are analytically connected with each other via energy conservation, Relative Resolution can capture the structural and thermal behavior of (nonpolar) multi-component and multi-phase systems across state space. The current work is a natural continuation of our original communication [1]. Most importantly, we present the comprehensive mathematics of Relative Resolution, basically casting it as a multipole approximation at appropriate distances; the current set of equations importantly applies for all systems (e.g, polar molecules). Besides, we continue examining the capability of our multiscale approach in molecular simulations, importantly showing that we can successfully retrieve not just the statics but also the dynamics of liquid systems. We finally conclude by discussing how Relative Resolution is the inherent variant of the famous "cell-multipole" approach for molecular simulations

    Bidding With Securities: Auctions and Security Design

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    We study security-bid auctions in which bidders compete by bidding with securities whose payments are contingent on the realized value of the asset being sold. Such auctions are commonly used, both formally and informally. In formal auctions, the seller restricts bids to an ordered set, such as an equity share or royalty rate, and commits to a format, such as first or second-price. In informal settings with competing buyers, the seller does not commit to a mechanism upfront. Rather, bidders offer securities and the seller chooses the most attractive bid, based on his beliefs, ex-post. We characterize equilibrium payoffs and bidding strategies for formal and informal auctions. For formal auctions, we examine the impact of both the security design and the auction format. We define a notion of the steepness of a set of securities, and show that steeper securities lead to higher revenues. We also show that the revenue equivalence principle holds for equity and cash auctions, but that it fails for debt (second-price auctions are superior) and for options (a first-price auction yields higher revenues). We then show that an informal auction yields the lowest possible revenues across all possible formal mechanisms. Finally, we extend our analysis to consider the effects of liquidity constraints, different information assumptions, and aspects of moral hazard.

    Computational studies of biomembrane systems: Theoretical considerations, simulation models, and applications

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    This chapter summarizes several approaches combining theory, simulation and experiment that aim for a better understanding of phenomena in lipid bilayers and membrane protein systems, covering topics such as lipid rafts, membrane mediated interactions, attraction between transmembrane proteins, and aggregation in biomembranes leading to large superstructures such as the light harvesting complex of green plants. After a general overview of theoretical considerations and continuum theory of lipid membranes we introduce different options for simulations of biomembrane systems, addressing questions such as: What can be learned from generic models? When is it expedient to go beyond them? And what are the merits and challenges for systematic coarse graining and quasi-atomistic coarse grained models that ensure a certain chemical specificity

    Investigation of the oxohalogenide Cu4Te5O12Cl4 with weakly coupled Cu(II) tetrahedra

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    The crystal structure of the copper(II) tellurium(IV) oxochloride Cu4_{4}Te5_{5}O12_{12}Cl4_{4} (Cu-45124) is composed of weakly coupled tetrahedral Cu clusters and shows crystallographic similarities with the intensively investigated compound Cu2_{2}Te2_{2}O5_{5}X2_{2}, with X~=~Cl, Br (Cu-2252). It differs from the latter by a larger separation of the tetrahedra within the crystallographic ab plane, that allows a more direct assignment of important inter-tetrahedra exchange paths and the existence of an inversion center. Magnetic susceptibility and specific heat evidence antiferromagnetic, frustrated correlations of the Cu spin moments and long range ordering with TcT_{c}=13.6 K. The entropy related to the transition is reduced due to quantum fluctuations. In Raman scattering a well structured low energy magnetic excitation is observed at energies of \approx50K (35cm1)^{-1}). This energy scale is reduced as compared to Cu-2252.Comment: 11 pages, 9 figures, further information see http://www.peter-lemmens.d

    Endogenous Information Flows and the Clustering of Announcements

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    We consider the release of information by a firm when the manager has discretion regarding the timing of its release. While it is well known that firms appear to delay the release of bad news, we examine how external information about the state of the economy (or the industry) affects this decision. We develop a dynamic model of strategic disclosure in which a firm may privately receive information at a time that is random (and independent of the state of the economy). Because investors are uncertain regarding whether and when the firm has received information, the firm will not necessarily disclose the information immediately. We show that bad news about the economy can trigger the immediate release of information by firms. Conversely, good news about the economy can slow the release of information by firms. As a result, the release of negative information tends to be clustered. Surprisingly, this result holds only when firms can preempt the arrival of external information by disclosing their own information first. These results have implications for conditional variance and skewness of stock and market returns

    The application of social network analysis to team sports

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    This article reviews how current social network analysis might be used to investigate individual and group behavior in sporting teams. Social network analysis methods permit researchers to explore social relations between team members and their individual-level qualities simultaneously. As such, social network analysis can be seen as augmenting existing approaches for the examination of intra-group relations among teams and provide detail of team members\u27 informal connections to others within the team. Social network analysis is useful in addressing the issue of interdependencies in the data inherent in team structures. Social network terms are introduced and explained by way of an example team, software and resources are discussed, and a statistical approach to social network analysis is introduced. <br /
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