Phase space description of the dynamics due to the coupled effect of the planetary oblateness and the solar radiation pressure perturbations

The aim of this work is to provide an analytical model to characterize the equilibrium points and the phase space associated with the singly-averaged dynamics caused by the planetary oblateness coupled with the solar radiation pressure perturbations. A two-dimensional differential system is derived by considering the classical theory, supported by the existence of an integral of motion comprising semi-major axis, eccentricity and inclination. Under the single resonance hypothesis, the analytical expressions for the equilibrium points in the eccentricity-resonant angle space are provided, together with the corresponding linear stability. The Hamiltonian formulation is also given. The model is applied considering, as example, the Earth as major oblate body, and a simple tool to visualize the structure of the phase space is presented. Finally, some considerations on the possible use and development of the proposed model are drawn

Addition energies in semiconductor quantum dots: Role of electron-electron interaction

We show that the addition spectra of semiconductor quantum dots in the presence of magnetic field can be studied through a theoretical scheme that allows an accurate and practical treatment of the single particle states and electron-electron interaction up to large numbers of electrons. The calculated addition spectra exhibit the typical structures of Hund-like shell filling, and account for recent experimental findings. A full three dimensional description of Coulomb interaction is found to be essential for predicting the conductance characteristics of few-electron semiconductor structures.Comment: LaTeX 2.09, RevTeX, 3 pages, 3 Postscript figure

Quantum interference in nanometric devices: ballistic transport across arrays of T-shaped quantum wires

We propose that the recently realized T-shaped semiconductor quantum wires (T-wires) could be exploited as three-terminal quantum interference devices. T-wires are formed by intersecting two quantum wells (QWs). By use of a scattering matrix approach and the Landauer-B\"uttiker theory, we calculate the conductance for ballistic transport in the parent QWs and across the wire region as a function of the injection energy. We show that different conductance profiles can be selected by tailoring the widths of the QWs and/or combining more wires on the scale of the Fermi wavelength. Finally, we discuss the possibility of obtaining spin-dependent conductance of ballistic holes in the same structures.Comment: To appear in the 09/15/97 issue of Appl. Phys. Lett. (9 pages in REVTEX + 2 figures in postscript

Financial integration estimation with realized measures

The objective of this study is to provide a new evidence on time-varying equity market integration, employing alternative econometric specifications of the conditional covariance process. Differently from the current literature on the topic, we specify alternative econometric models for the conditional covariance of stock indexes which include as a measure of past variability the monthly realized covariances. We analyze the degree of integration with the rest of the world of European equity markets and its variation through time. We cast our analysis in the framework provided with by the International Asset Pricing Model (IAPM). This model accommodates the evolving market structure from segmentation to integration as well as intermediate cases, depending on the existence of barriers to investments and the availability of substitute assets. Our analysis provides evidence that in recent years most of European Markets become more integrated with the world market. The local risk factor does not seem to be a determinant factor in the European markets, in the sample period considered. Its contribution to the total time-varying risk premium is only marginal.JRC.B.1-Finance and Econom

Psycho-relational well-being in women with sexual pain: a preliminary study

Female sexual pain is a complex multi-factorial condition. Most of the research has focused on underlying biomedical factors. Although psychological and relational factors have been studied as possible correlates, data are still controversial. The aim of the present study was to investigate psychological and relational well-being in women who complain of sexual pain. The hypothesis was that sexual pain is associated with worse scores