The breathing-mode isoscalar giant monopole resonance (GMR) is investigated using the generator coordinate method within the relativistic mean-field (RMF) theory. Employing the Lagrangian models of the nonlinear-σ model (NLσ), the scalarvector interaction model (SVI) and the σ-ω coupling model (SIGO), we show that each Lagrangian model exhibits a distinctly different GMR response. Consequently,...

Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical te...

Hyperpolarizability ratios for molecules have been measured with 0.1% accuracy, at I = 5 14.5 nm, in the gas phase as a function ofdensity. These measurements yieldy(Hz)/y(He)= 19.55kO.03, y(Ar)/y(Hz)=1.668f0.002 and y(N~)/y(Hz)= 1.283+0.001 in the zero density limit. Pair interaction contributions, determined from the density dependence of y, are larger than predicted assuming classical multip...

We report on the observation of ultralong range interactions in a gas of cold rubidium Rydberg atoms. The van der Waals interaction between a pair of Rydberg atoms separated as far as 100,000 Bohr radii features two important effects: spectral broadening of the resonance lines and suppression of excitation with increasing density. The density dependence of these effects is investigated in detai...

Shell-model calculations for the s-d shell nuclei and Sn isotopes are performed using Hartree-Fock wave functions and two-body matrix elements based upon the SGII Skyrme-type density-dependent interaction. We reproduce the spectra of several nuclei from the beginning to the end of the s-d shell. The experimental pairing gaps for the Sn isotopes are also obtained from calculations in the general...

The immediate and delayed effects of embryonic exposure to low levels of polynuclear aromatic hydrocarbons (PAHs) have been shown to reduce survival to maturity by 50% in exposed pink salmon populations. This suggests that chronically exposed populations could be extirpated over relatively few generations, but the effect of density dependence on extirpation rate is unknown. This study examines ...

Identifying the steady states of a population is a key issue in theoretical ecology, that includes the study of spatially heterogeneous populations. There are several examples of real ecosystems in patchy environments where the habitats are heterogeneous in their local density dependence. We investigate a multi-patch model of a single species with spatial dispersal, where the growth of the loca...

Most studies of density-dependent demography in plants consider the density only of the single focal species being studied. However, density-dependent regulation in plants may frequently occur at the level of the entire community, rather than only within particular species. In addition, because density dependence may differ considerably (even in direction) among demographic parameters, generali...

The latest development in determining the density dependence of the nuclear symmetry energy using heavy-ion collisions is reviewed. Within the IBUU04 version of an isospinand momentum-dependent transport model using a modified Gogny effective interaction, recent experimental data from NSCL/MSU on isospin diffusion are found to be consistent with a nuclear symmetry energy of Esym(ρ) ≈ 31.6(ρ/ρ0)...