model life tables are a key methodological tool for the study of mortality, especially in countries where statistics are incomplete. the tables published by the united nations in 1982 paved the way for considerable progress in this field. now that more complete and reliable data are available, the use and interpretation of these tables can be critically assessed. zhongwei zhao shows here that m...

Arab people, who have inhabited vast arid areas of the Middle East, were originally nomadic pastoralists, called Bedouin, and most of them have changed their lifestyle from nomadism to sedentarism due to several reasons such as droughts in pasture lands, overpopulation and the governmental policy for promoting their settlement (Lewis, 1987; Bocco, 2000). In Jordan, a typical Arab country, the p...

Because of recent findings that Fe is a limiting factor for phytoplankton activity even at relatively high dissolved iron (DFe) concentrations, the potential importance of Fe limitation was revisited in the northeast Atlantic Ocean (39–458N, 17–218W). We report data gathered during deck incubation experiments performed at three stations in February–March 2001 with surface seawater containing DF...

With the discovery of the existence and importance of the picophytoplankton and the microbial loop, a new paradigm of planktonic communities has arisen: the autotrophic picoplankton can generally outcompete the larger phytoplankton for nutrients. The picoplankton, however, are grazed by protists, which have short response time scales—similar to the generation times of the picoplankton. The rapi...

the first demographic transition started in many western industrialized societies around the latter part of the nineteenth century with steady mortality improvement. expectation of life at birth, about 40 years at the start of the transition, has now doubled (riley 2001). Fertility declined from a level of about five children to under two children per woman over the same period (Coale and watki...

process will induce subsequent sterility, which causes high-parity women of any given age to be more likely to have become sterile than lower-parity women of the same age). It is perhaps surprising also that the discussion of methods of detecting the presence of deliberate control of fertility in marriage from the statistical patterns of child-bearing contains no reference to the methods devise...

The uptake and efflux of 64Cu was studied in the marine cyanobacterium Synechoccous strain WH7803 (DC2). Uptake followed classical Michaelis-Menten type kinetics in metal-buffered seawater. The maximum uptake rate, Vmax, was 0.236 6 0.016 3 10218 mol Cu cell21 h21, with the half-saturation constant, KS, of 10210.8160.11 mol L21. An efflux mechanism was also observed in WH7803, whose growth was ...