The Transmuted Weibull-Pareto Distribution

A new generalization of the Weibull-Pareto distribution called the transmuted Weibull-Pareto distribution is proposed and studied. Various mathematical properties of this distribution including ordinary and incomplete moments, quantile and generating functions, Bonferroni and Lorenz curves and order statistics are derived. The method of maximum likelihood is used for estimating the model parameters. The flexibility of the new lifetime model is illustrated by means of an application to a real data set

Understanding the sub-critical transition to turbulence in wall flows

Contrasting with free shear flows presenting velocity profiles with inflection points which cascade to turbulence in a relatively mild way, wall bounded flows are deprived of (inertial) instability modes at low Reynolds numbers and become turbulent in a much wilder way, most often marked by the coexistence of laminar and turbulent domains at intermediate Reynolds numbers, well below the range where (viscous) instabilities can show up. There can even be no unstable mode at all, as for plane Couette flow (pCf) or for Poiseuille pipe flow (Ppf) that currently are the subject of intense research. Though the mechanisms involved in the transition to turbulence in wall flows are now better understood, statistical properties of the transition itself are yet unsatisfactorily assessed. A review of the situation is given. An alternative to the temporal theory of the transition to turbulence in terms of chaotic transients in such globally subcritical flows is proposed, which invokes spatio-temporal intermittence and the theory of first order (thermodynamic) phase transitions.Comment: 15 pages, 7 figures; proceedings of the Conference and Workshop on Perspectives in Nonlinear Dynamics, Trieste, 200

Elaboration of the Coale-McNeil Nuptiality Model as The Generalized Log Gamma Distribution

The Coale-McNeil nuptiality model is a particular case of the generalized log gamma distribution model. In this paper, we demonstrate that recognition of this connection allows an expansion of the possible applications of the Coale-McNeil model. As examples, we propose a procedure to develop country specific standard schedules, and illustrate the utility in regression analysis (directly and via the competing risk framework). In addition, we employ this identification to enhance the ability of the models with empirical adjustment to trace the trajectory of the lifetime schedule for cohorts which have not completed the process. We illustrate an application to Japanese female cohorts. We also propose an application to fertility projection by modeling the fertility schedule by birth order.Coale-McNeil nuptiality model, fertility projection, first marriage schedule, generalized gamma distribution, marriage, nuptiality

Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum

We present evidence showing how antiprotonic hydrogen, the quasistable antiproton-proton (pbar-p) bound system, has been synthesized following the interaction of antiprotons with the hydrogen molecular ion (H2+) in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events, evidence is presented for antiprotonic hydrogen production with sub-eV kinetic energies in states around n=70, and with low angular momenta. The slow antiprotonic hydrogen may be studied using laser spectroscopic techniques.Comment: 5 pages with 4 figures. Published as Phys. Rev. Letters 97, 153401 (2006), in slightly different for