نتایج جستجو برای: population concentration
تعداد نتایج: 1056481 فیلتر نتایج به سال:
BACKGROUND The objective was to compare the pattern of exposure to second-hand smoke (SHS) among non-smokers in the general population and in hospitality workers. METHODS We used the adult (16-64 years) non-smokers of two independent studies (general population and hospitality workers) in Spain. We assessed the exposure to SHS by means of questionnaire and salivary cotinine concentration. R...
Understanding the mechanisms controlling the generation and maintenance of biodiversity provides some of the planet's greatest and most pressing challenges. Variation in resource concentration, which varies widely at multiple scales, may cause biodiversity to increase, decrease, or exhibit a unimodal response and underlying mechanisms remain obscure. We established experimental cultures of long...
The objective of the present research was to investigate the effect of salinity stress on sodium, potassium and calcium concentrations, and Na+/K+ and Na+/Ca2+ ratios at seedling stage in an advanced back cross (BC2F6) rice population. The population was derived from crossing between Hashemi, an Iranian cultivar, and IR67418-110-32222 (IR-22) from IRRI. The ANOVA indicated that the effects of g...
"We find that a nation's urban population percentage increases with GDP per capita; industrialization; export orientation; and possibly, foreign assistance. It decreases with the importance of agriculture. Industrialization and agricultural importance have the same implications for the concentration of urban population in cities with 100,000+ population as for the urban percentage. Greater exp...
Lolium perenne has symbiosis relationships with an important group of endophytes genus Neotyphodium. Agronomic traits of this plant and its resistance to biotic and abiotic stresses are affected by Neotyphodium spp., resulting to changes in its physiology and morphology. Effect of Nickel and endophyte symbiosis on growth parameters and nickel uptake in two different natural populations are inve...
OBJECTIVE To determine an optimal population red blood cell (RBC) folate concentration for the prevention of neural tube birth defects. DESIGN Bayesian model. SETTING Data from two population based studies in China. PARTICIPANTS 247,831 participants in a prospective community intervention project in China (1993-95) to prevent neural tube defects with 400 μg/day folic acid supplementation ...
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