Many scholars have argued that deliberate birth spacing may have played a role before and during the modern fertility transition. There are good historical and theoretical reasons for this view, but it has proved to be hard to demonstrate convincingly that birth intervals were in fact partly determined by attempts at deliberate fertility control. This paper suggests a method of securing evidenc...

We propose a mean-field method to calculate approximately the spacing distribution functions p((n))(s) in one-dimensional classical many-particle systems. We compare our method with two other commonly used methods, the independent interval approximation and the extended Wigner surmise. In our mean-field approach, p((n))(s) is calculated from a set of Langevin equations, which are decoupled by u...

OBJECTIVES This paper examines the effect of household crowding on inter-pregnancy spacing and its association with socioeconomic indicators, among parous mothers delivered in an urban environment. DESIGN Cross sectional survey. METHODS Sociodemographic data were obtained on 2466 parous women delivering at eight hospitals in Greater Beirut over a one year period. Statistical methodology com...

Design of thinned semi-elliptical and quarter-elliptical antenna arrays, with uniform excitation and uniform spacing using genetic algorithm (GA) optimization, is presented in this paper. Thinned arrays produce narrow directive beam without causing major degradation of fully populated antenna arrays. Semi-elliptical array contains antenna elements along half of the elliptical geometry and quart...

This paper presents design, fabrication and characterization of an electromagnetic energy harvester, which can operate at different resonance frequencies. It utilizes magnetic spring technique to scavenge energy from low frequency vibrations. The optimization of generator is done in two stages. First, optimization of a single harvester is done in terms of number of turns, coil width, coil posit...

In this paper we formulate three classes of optimization problems: the simple, monotonically constrained, and bounded Cong–He (CH)-programs. We reveal the dominance property under the local refinement (LR) operation for the simple CH-program, as well as the general dominance property under the pseudo-LR operation for the monotonically constrained CH-program and the extended-LR operation for the...