5,261 research outputs found
SEVENTEEN FAMOUS ECONOMISTS WEIGH IN ON COPYRIGHT: THE ROLE OF THEORY, EMPIRICS, AND NETWORK EFFECTS
In 2002, seventeen economists including five Nobel Laureates presented an amicus curiae brief discussing the economics of copyright extension in support of the petitioners in Eldred v. Ashcroft. The economistsâ amicus brief was unusual in several respects, not least in that it brought together a group of economists almost as notable for its diversity of opinion (spanning the ideological spectrum from Kenneth Arrow to Milton Friedman) as for its academic distinction. When such a distinguished and broad panel of economists readers would have every reason to believe that the arguments set forth in this document are sound down to the smallest details. Yet this is not the case. Scholars in the fields of law and economics will continue to address the economics of copyright duration in the foreseeable future, so it is important that they understand the imperfections in the economistsâ brief. This Article provides a counterweight to the amicus brief, identifying some points the economists ignored, clarifying some discussions they did not quite get right, and providing data that runs counter to some assumptions they made.Eldred, coypright, sonny bono, lessig
The Marangoni effect and translation of free non-deformable drops
A model is presented for flow caused by interface tension gradients, the so called Marangoni effect, on a free, nondeformable drop. A free drop, initially at rest, undergoes a translation motion upon the action of surface flow. The experiments carried out by injecting a drop with surfactants, which induce an interface tension gradient, are in good agreement with the theoretical model proposed
Discretised Non-Linear Filtering for Dynamic Latent Variable Models: with Application to Stochastic Volatility
Filtering techniques are often applied to the estimation of dynamic latent variable models. However, these techniques are often based on a set assumptions which restrict models to be specified in a linear state-space form. Numerical filtering techniques have been propsed that avoid invoking such restrictive assumptions, thus permitting a wider class of latent variable models to be considered. This paper proposes an accurate yet computationally efficient numerical filtering algorithm (based on a discretisation of the state space) for estimating the general class of dynamic latent variable models. The empirical performance of this algorithm is considered within the context of the stochastic volatility model. It is found that the proposed algorithm outperforms a number of accepted procedures in terms of volatility forecastiNon-linear filtering, latent variable models, stochastic volatility, volatilitry forecasting
Propane Dehydrogenation Using Transition Metal Cluster Catalysts
Our research seeks to determine the propane dehydrogenation (PDH) reaction pathways using various transition-metal cluster catalysts. We are studying the first step of the reaction, in which a C-H bond is broken. This has been previously shown to be the rate-limiting step of the PDH reaction. We are calculating the PDH activation energy (Ea) using the Vienna Ab-Initio Simulation Package (VASP) in conjunction with the nudged elastic band algorithm. Thus far, we have studied Pt, Ta, and Ni clusters ranging in size from 2-10 atoms. Our goal is to better understand the dependence of Ea on metal type and cluster size
Comparative study of many-body perturbation theory and time-dependent density functional theory in the out-of-equilibrium Anderson model
We study time-dependent electron transport through an Anderson model. The
electronic interactions on the impurity site are included via the self-energy
approximations at Hartree-Fock (HF), second Born (2B), GW, and T-Matrix level
as well as within a time-dependent density functional (TDDFT) scheme based on
the adiabatic Bethe-Ansatz local density approximation (ABALDA) for the
exchange correlation potential. The Anderson model is driven out of equilibrium
by applying a bias to the leads and its nonequilibrium dynamics is determined
by real-time propagation. The time-dependent currents and densities are
compared to benchmark results obtained with the time-dependent density matrix
renormalization group (tDMRG) method. Many-body perturbation theory beyond HF
gives results in close agreement with tDMRG especially within the 2B
approximation. We find that the TDDFT approach with the ABALDA approximation
produces accurate results for the densities on the impurity site but
overestimates the currents. This problem is found to have its origin in an
overestimation of the lead densities which indicates that the exchange
correlation potential must attain nonzero values in the leads.Comment: 11 pages, 9 figure
Quasi-one and two-dimensional transitions of gases adsorbed on nanotube bundles
Grand canonical Monte Carlo simulations have been performed to determine the
adsorption behavior of Ar and Kr atoms on the exterior surface of a rope
(bundle) consisting of many carbon nanotubes. The computed adsorption isotherms
reveal phase transitions associated with the successive creation of quasi-one
dimensional lines of atoms near and parallel to the intersection of two
adjacent nanotubes.Comment: 12 pages, 6 figures, submitted to J. Chem. Phy
Characterization of the Sequential Product on Quantum Effects
We present a characterization of the standard sequential product of quantum
effects. The characterization is in term of algebraic, continuity and duality
conditions that can be physically motivated.Comment: 11 pages. Accepted for publication in the Journal of Mathematical
Physic
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