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...

-Infrared spectroscopic, X-ray powder diffraction, diffuse reflectance, and electron-spin resonance examination of homoionic bentonite from Sardinia treated with diazomethane indicates that polymethylene was formed in the interlayer position. Polymerization can be attributed to the acidic properties of the residual water in the interlamellar space, depending on the nature of the exchanged ion. ...

Two new species of oribatid mites of the genus Macrogena (Oribatida, Ceratozetidae) are described from alpine soils of the South Island of New Zealand. Macrogenabrevisensilla sp. n. and Macrogenaabbreviata sp. n. differ from all species of this genus by the tridactylous legs and by the comparatively short interlamellar setae, respectively. New generic diagnosis and an identification key to the ...

Two new species of oribatid mites the genus Xenillus (Oribatida, Liacaridae) are described from leaf litter in a rain forest Bolivia. pseudobolivianus sp. n. is similar to X. bolivianus and neonominatus morphology lamellar cusp, length bothridial interlamellar setae dorsal notogastral setae, but differs both by head ornamentation notogaster, different some setae. amboroensis amazonensis, disjun...