Photoabsorption Spectra of Na_n+ clusters: Thermal Line-Broadening Mechanisms

Photoabsorption cross sections of small sodium cluster cations (Na$_n^+$, n=3,5,7 and 9) were calculated at various temperatures with the time-dependent local-density-approximation (TDLDA) in conjunction with ab initio molecular dynamics simulations, yielding spectra that agree with measured ones without ad-hoc line broadening or renormalization. Three thermal line-broadening mechanisms are revealed: (I) lifting of level degeneracies caused by symmetry-breaking ionic motions, (II) oscillatory shifts of the entire spectrum caused by breathing vibrations, and (III) cluster structural isomerizations.Comment: 4 pages,2 figures, to appear in Phys. Rev. Let

The three-dimensional instability of strained vortices in a viscous fluid

The recent theory describing 3-D exact solutions of the Navier–Stokes equations is applied to the problem of stability of 2-D viscous flow with elliptical streamlines. An intrinsically inviscid instability mechanism persists in all such flows provided the length scale of the disturbance is sufficiently large. Evidence is presented that this mechanism may be responsible for 3-D instabilities in high Reynolds number flows whose vortex structures can be locally described by elliptical streamlines

Qualitative Analysis of Alcohol’s Acute Effect on Vocal Range

Alcoholic beverages are the most popular human-produced drinks in history. Whether it is wine, beer, or hard liquor, alcoholic beverages are included in all aspects of society. Presidents, town drunks, and the greatest musical sensations are seen drinking alcoholic beverages both at work and at home. In terms of its effects on individuals, alcohol is deemed to be a poison to the body, and drinking too much can destroy your liver and your body as a whole. This puts public speakers, political leaders, and specifically singers in an odd position when it comes to balancing casual alcohol consumption and retaining their vocal health. Scientific study of this subject is necessary, as well as close consideration of the effects of alcohol on singer’s lives and careers. There is already extensive research pertaining to the chronic effects of alcohol on the body. In terms of acute alcohol ingestion, research does not exist to the same level of detail or quality. The effect of alcohol on vocal range, both chronic and acute, has not been studied thoroughly. Alcohol has many negative effects on the voice. In this study, we suggest that acute alcohol ingestion may decrease the vocal range of individuals

Crystalline boson phases in harmonic traps: Beyond the Gross-Pitaevskii mean field

Strongly repelling bosons in two-dimensional harmonic traps are described through breaking of rotational symmetry at the Hartree-Fock level and subsequent symmetry restoration via projection techniques, thus incorporating correlations beyond the Gross-Pitaevskii (GP) solution. The bosons localize and form polygonal-ring-like crystalline patterns, both for a repulsive contact potential and a Coulomb interaction, as revealed via conditional-probability-distribution analysis. For neutral bosons, the total energy of the crystalline phase saturates in contrast to the GP solution, and its spatial extent becomes smaller than that of the GP condensate. For charged bosons, the total energy and dimensions approach the values of classical point-like charges in their equilibrium configuration.Comment: Published version. Typos corrected. REVTEX4; 5 pages with 3 PS figures. For related papers, see http://www.prism.gatech.edu/~ph274c

Bosonic molecules in rotating traps

We present a variational many-body wave function for repelling bosons in rotating traps, focusing on rotational frequencies that do not lead to restriction to the lowest Landau level. This wave function incorporates correlations beyond the Gross-Pitaevskii (GP) mean field approximation, and it describes rotating boson molecules (RBMs) made of localized bosons that form polygonal-ring-like crystalline patterns in their intrinsic frame of reference. The RBMs exhibit characteristic periodic dependencies of the ground-state angular momenta on the number of bosons in the polygonal rings. For small numbers of neutral bosons, the RBM ground-state energies are found to be always lower than those of the corresponding GP solutions, in particular in the regime of GP vortex formation.Comment: To appear in Phys. Rev. Lett. LATEX, 5 pages with 5 figures. For related papers, see http://www.prism.gatech.edu/~ph274cy

The role of the mental health practitioner in divorce and custody litigation

Bibliography: pages 189-208.Two elements have been isolated as having a profound effect on the adjustment of children and families to post-divorce life. These are the hostility expressed and experienced before, during and after the divorce, and the losses experienced as a result of the final settlement terms. Based on a review of the historical development of family law and the more recent reforms adopted throughout the Western World, the present shortfalls of the South African system of family law in providing for the needs of children and families in divorce have been identified. A model of dissolution is presented which aims primarily at the reduction of the hostility and loss thus experienced. This includes the evaluation and updating of the 'best interests' standard used by the courts for arriving at custody/access settlements and a detailed discussion of the role played by the mental health professional at each stage of the dissolution process. The roles explored here include that of counsellor and facilitator in the pre-divorce, mediation and post-divorce stages; and the role of investigator/consultant and expert witness in the court process