Recent analyses of radial growth rates in southern commercial forests have shown that current rates are lower than past rates when compared diameter class by diameter class. These results have been interpreted as an indication that the growth rate of the forest is declining. In this paper, growth rates of forest populations in Alabama are studied. Basal area growth (a function of both radius an...

In this study, we describe the growth of carbon nanotubes on commercial iron nanoparticles without carbon shell (Fe (nm), size 2O3 and Fe* (nm)/MgO) was carried out by mixing commercial Fe* nanoparticles (as catalyst) with Al2O3 and MgO powders (as supports)by using ball-milling method. The results show in spite of the fact that ball-milling process can have neg...

      Dust storms are increasingly threatening the forest ecosystem in Western Iran. Due to its coverage of vast area of Zagros forest, the Quercus brantii is at the front line of the attack. Most tree deaths in this forest are from this species. This study aims to investigate the effect of simulated dust on wood development and leaf stomata from seedlings of Persian oak. The oak seedlings were...

the teratogenicity of cadmium exposure was studied in virgin nimri rats aged 10-13 weeks. pregnant animals were fed cadmium sulfate equivalent to doses of 1,4 and 7 mg/kg/day of cadmium by oral gavage on the day 7 of gestation. on the day 18 of gestation, fetuses were delivered and examined for external and skeletal malformations. total percent of malformed fetuses in rats treated by different ...

'Dwarf stature' maize variety offers promises to withstand unfavorable growth environments of Kharif season. But, for developing such variety, dwarf stature inbred lines must be available. Here, twenty-four F3 populations of white maize were evaluated though assessment of their genetic variability, heritability, and character association for selection of dwarf stature promising lines based on y...

plant spacing and nitrogen are the most important factors for increasing tuberose quality and quantity. in this study, field experiment carried out as factorial randomized completely block design (rcbd) in 3 replications. different levels of nitrogen (0, 50, 100, 150, 200, 250 kg/ha) of ammonium nitrate was used. second factor was different plant spaces (10, 15, 20 and 25 cm). results showed th...

Zhang et al. (2005) present a parameterization for what they term the "growth factor" of a sea salt aerosol particle relative to its formation diameter, which they assert "is a function of relative humidity alone" and independent of an arbitrary reference relative humidity. Here we note that this growth factor implicitly assumes an arbitrary reference relative humidity through the salinity of t...