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...

Original scientific paper Based on the experimental research on three cross-shaped columns with 500 MPa grade reinforcing steel bars, the contrastive analysis is made on failure mode, bearing capacity and displacement ductility of each column specimens with different stirrup spacing under the identical axial compression ratio. The research shows that the longitudinal bars yield before spalling ...

Smart antenna technology is a challenging area in the development of wireless communications. Using smart antennas the quality of a radio link can be improved by many ways. Smart antennas are active antenna arrays or groups with changeable complex-valued weights at inputs and outputs. Good electrical matching of the array and the similarity and ideality of element patterns is usually expected. ...

An alternative method for port decoupling and matching of arrays with small inter-element spacing is proposed. The approach is based on the inherent decoupling effect obtained by feeding the eigenmodes of the array. For this purpose, a modal feed network is introduced. The decoupled external ports of the feed network may individually be matched using conventional matching circuits. Such a syste...

The best way of gain enhancement can be obtained is from the array models, but there are some problems associated with array antennas. Mutual coupling losses, element spacing and design complexity are major concerns in the array antennas. The present paper deals with the performance characterization among the 2X2, 3X3, 4X4 array antennas. Rectangular patch array models are constructed and simul...