Floating millenial chronologies of Pinus in the Sierra de Gredos (Spain)

This research has been carried out by some members of the “History and Dynamics of the Vegetal Landscape” Research Group of the Technical University of Madrid (Spain). The team has been working on the flora, vegetation and dendrochronology of the Sierra de Gredos (Ávila, Spain) for the last 20 years. Recently, we have implemented a new research field focused on the study of megafossils. All this data set has allowed us to develop an interpretation of the dynamics of mountain pine forests in this region

Numerical shadow and geometry of quantum states

The totality of normalised density matrices of order N forms a convex set Q_N in R^(N^2-1). Working with the flat geometry induced by the Hilbert-Schmidt distance we consider images of orthogonal projections of Q_N onto a two-plane and show that they are similar to the numerical ranges of matrices of order N. For a matrix A of a order N one defines its numerical shadow as a probability distribution supported on its numerical range W(A), induced by the unitarily invariant Fubini-Study measure on the complex projective manifold CP^(N-1). We define generalized, mixed-states shadows of A and demonstrate their usefulness to analyse the structure of the set of quantum states and unitary dynamics therein.Comment: 19 pages, 5 figure

Realized beta : persistence and predictability

A large literature over several decades reveals both extensive concern with the question of time-varying betas and an emerging consensus that betas are in fact time-varying, leading to the prominence of the conditional CAPM. Set against that background, we assess the dynamics in realized betas, vis-à-vis the dynamics in the underlying realized market variance and individual equity covariances with the market. Working in the recently-popularized framework of realized volatility, we are led to a framework of nonlinear fractional cointegration: although realized variances and covariances are very highly persistent and well approximated as fractionally-integrated, realized betas, which are simple nonlinear functions of those realized variances and covariances, are less persistent and arguably best modeled as stationary I(0) processes. We conclude by drawing implications for asset pricing and portfolio management. JEL Klassifikation: C1, G

An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics

In this paper we present a method to derive an exact master equation for a bosonic system coupled to a set of other bosonic systems, which plays the role of the reservoir, under the strong coupling regime, i.e., without resorting to either the rotating-wave or secular approximations. Working with phase-space distribution functions, we verify that the dynamics are separated in the evolution of its center, which follows classical mechanics, and its shape, which becomes distorted. This is the generalization of a result by Glauber, who stated that coherent states remain coherent under certain circumstances, specifically when the rotating-wave approximation and a zero-temperature reservoir are used. We show that the counter-rotating terms generate fluctuations that distort the vacuum state, much the same as thermal fluctuations.Finally, we discuss conditions for non-Markovian dynamics

Parametric CFD study of an air curtain for smoke confinement

The CFD simulation of an air curtain for smoke confinement in case of fire is conducted by using Fire Dynamics Simulator (FDS 6.0.1). It is a working progress of preliminary simulation for preparation of small scale experiment. The set-up is a wind tunnel configuration. Special focus is given to the smoke flow field, jet velocity and temperature distribution in the protected area. Predicted ceiling jet properties are compared with analytical equations. Investigation of different jet velocities reveals that the smoke flow field in the wind tunnel is strongly influenced by the operation of air curtain. Jet velocity between 0.75m-1m/s is recommended for the study at hand