نتایج جستجو برای: zinc and cadmium levels on concentration
تعداد نتایج: 18583982 فیلتر نتایج به سال:
this study investigated the effects of manipulating the cognitive complexity of tasks along +/- few elements and the time limits on l2 learners writing performance. to conduct the study, 60 iranian efl learners with two levels of proficiency, low and high intermediate, were selected and assigned to three groups based on the time devoted to task completion. the participants performed both a simp...
Bacteria have evolved various types of resistance mechanism to toxic soft metals and metalloids, including cadmium/zinc, copper/silver and arsenic/antimony. Active efflux of the metal is a frequently utilized stratagem to produce resistance by lowering the intracellular concentration to subtoxic levels. Reduction to a less-toxic form or to a form recognized by an efflux system also occurs. Pump...
Abbasi, S. A. and R. Soni (1986). "An examination of environmentally safe levels of zinc (II), cadmium (II) and lead (II) with reference to impact on channelfish Nuria denricus." Environmental Pollution Series A, Ecological and Biological 40(1): 37-51. As a continuation of our earlier studies on the impact of heavy metals on aquatic organisms (Abbasi & Soni, 1984), the behavioural responses and...
the present study was an attempt to determine the types of motivation and levels of foreign language learning anxiety among efl students studying at azad and state universities in kermanshah and to determine the relationship between these two factors and language proficiency and gender. to this end, the foreign language learning motivation scale, by deci and ryan )1985(, were administered to 12...
background: this study was performed to evaluate the levels of heavy metals in the livers and kidneys of cattle, sheep and goats from a mining region in the west of iran. methods: in this cross-sectional study, 90 samples were collected from the livers and kidneys of cattle (n=30), sheep (n=30) and goats (n=30) from a slaughterhouse in hamedan city, western iran. lead, cadmium, manganese, zinc,...
Sediments play an effective role in pollution control or water purification of the wetland ecosystem and record heavy metals contamination as an historical archive. Ganduman wetland is one of the top 10 birdwatching wetlands in Iran. This study aimed to to investigate the concentration of lead, cadmium, copper and zinc in Ganduman sediments. For this purpose, sediment samples were collected man...
a selective and sensitive method for determination of cadmium and zinc is presented. the method is based on adsorptive accumulation of the complexes of cd (ii) and zn (ii) ions with 4-amiono-5-methyl-2,4-dihydro-3h-1,2,4-triazol-3-tion (mmtt) onto hanging mercury drop electrode (hmde), followed by reduction of the adsorbed species by voltammetric scan using differential pulse modulation. the li...
This report investigated the distribution of serum zinc and the factors determining serum zinc concentration in a large random population sample. The 1977 participants (959 men and 1018 women), 20-80 years old, constituted a stratified random sample of the population of four Belgian districts, representing two areas with low and two with high environmental exposure to cadmium. For each exposure...
Cadmium occurs in the earth’s crust at a concentration of 0.1–0.5 ppm and is commonly associated with zinc, lead, and copper ores. It is also a natural constituent of ocean water with average levels between <5 and 110 ng/L, with higher levels reported near coastal areas and in marine phosphates and phosphorites. The cadmium concentration of natural surface water and groundwater is usually <1 μg...
Cadmium occurs in the earth’s crust at a concentration of 0.1–0.5 ppm and is commonly associated with zinc, lead, and copper ores. It is also a natural constituent of ocean water with average levels between <5 and 110 ng/L, with higher levels reported near coastal areas and in marine phosphates and phosphorites. The cadmium concentration of natural surface water and groundwater is usually <1 μg...
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