with the aim to examine lead tolerance of populus nigra (clone 62/154) in symbiosis with arbuscular mycorrhizal fungi, a greenhouse experiment was carried out in a factorial randomized complete scheme with two factors 1) fungal inoculation in 4 levels (control, inoculation with glomus mosseae, inoculation with g. intraradices and inoculation with g. mosseae + g. intraradices) and 2) lead in 4 l...

for designing tillage implements it would be better to estimate soil forces exerted to the implements. many researches showed that numerical method of discrete element method (dem) is the cheapest and fastest technique for modeling granular material such as soil and especially sandy soil. in this study, paraplow and bentleg tines performance was compared with conventional tine using experimenta...

in order to investigate the effects of different irrigation regimes and zeolit on the yield, yield componentsand relative leaf water content of sorghum, a field experiment was conducted in split plot in time andspace based on randomized complete block design with three replicates in research station of shahidbahonar university of kerman in 2011. irrigation regimes (100, 80, 60 and 40% of field ...

beta-2 adrenoceptors in blood vessels are one of the active factors that play a role in regulation of tissue blood flow. in diabetic angiopathy, responsiveness of these receptors is decreased, while that is increased in inflammation. according to these opposite effects, the aim of this study was to investigate the vasodilatory response of knee joint blood vessels to salbutamol (beta-2 adrenocep...

this research is about analysis of relation between trust and organizational commitment of personnel. statistic social in this research is the personnel of social welfare organization of qom state and education organization of qom state and statical sample is consist of 35 employees from social welfare organization and 54 employees from education organization of qom state. in analysis of organi...

the aim of this study was to investigate the effect of adding different levels of zinc sulfate in semen extender on bovine sperm quality during cryopreservation. semen was collected from 4 holstein bull twice a week and the proper samples were pooled. semen were allocated to four extender treatments consisted of 0, 50, 100, 150 µm of zinc sulfate in 5 replicates and then, were frozen. post-thaw...

introduction prediction of thunderstorm is one of the most difficult issues in weather forecasting. deep convective clouds develop at small spatial and temporal dimensions about 1-10 km and 1-12 h. various thermodynamic parameters have been discovered over the past 40 years, according to data obtained by radiosounds. the capability of these indices in forecasting instability varies over time an...

an investigation of chlorophyll quick fluorsence variations was made in the reaserch field of islamic azad university- karaj in 2007. the experimental design was a split plot one in form of a complete randomized block design with 4 replications. drought stress was cosiderded in three levels of 40%, 60%, and 75%, on the basis of depletion of soil moisture as the main factor and the factor of mic...

introduction numerous studies have demonstrated the relationship between the amount of co2 in the atmosphere and climate change. in this respect, developed countries have an undeniable role and cause serious damage to earth environment throughout the world. ipcc’ forth evaluation report implies that adding greenhouse gases to the atmosphere during recent decades prevents the heat rays to emit w...

introduction climate is a system consisting of atmosphere, lithosphere, cryosphere, hydrosphere, and biosphere. this system is involved in the exchange of energy and moisture among these five components. the exchanges link the atmosphere as the central component of the climate to other spheres. changes do not occur separately in this system; rather change in one component contributes to reactio...