the aim of this study was to investigate the relationships between air, noise, light and landscape pollution on job stress of staff work in high schools of different districts (1, 2, 10 and 11) of tehran. this stress can reduce the efficiency of the personnel. the number of people participated in this research was 250, selected by random from different schools of the districts. the questionnair...

due to the use of secale montanum for different rangelands reclamation across the country, management of these ecosystems need to be aware of its ability to environmental stresses. this research investigated the effect of pollutant element of cu and pb on seed germination and growth of this species in laboratory. therefore, the effect of five treatments (control, 50, 100, 150, 200ppm) of pb (no...

introduction there are significant differences in the spatial distribution of the iran annual precipitation. this is resulted from spatial behavior of precipitation in the one hand and variation in the sources of precipitation on the other. the lack of adequate distribution of meteorological stations and the unavailability of long-term statistics of precipitation makes the analysis of precipita...

introduction precipitation is one of the most important meteorological variables in comparison with other climatic parameters. it varies extremely over time and space. the occurrence of this climate phenomenon requires specific circumstances in environment. its accurate measurement is important to a wide range of decision makers including hydrologists, agriculturalists, industrialists and etc. ...

in order to achieve a sustainable management and development of natural resources, a set of technical, eco-social, environmental and ecological criteria must be considered in the planning process. an appropriate model is therefore needed to address all the criteria mentioned above, in the decision making process and finally provide a reliable result. in the last few years, analytical hierarchic...

the purpose of this study was to examine the effectiveness of nanosilver colloid as a new antimicrobial agent against erwinia in tissue culture of sugar beet for the recovery of the contaminated doubled haploid plantlets. the nanosilver colloidal solution of 4000 ppm was diluted in different concentrations (0, 50, 75, 100 and 125 ppm) and was added to the solid ms medium. in a factorial experim...

stevia rebaudiana bertoni is a medicinal, perennial and herbaceous plant from asteraceae family with sweet glycosides in its leaves. salinity stress is one of the important limiters in agricultural productions. salinity influences the growth and development of plant by effect on more activities in physiological and morphological characteristics. to study the effect of salinity on morphological ...

evaluation of changes present in soil and water resources due to operation implement of floodwater spreading is necessary to assess their positive or negative resultant effect. rate of the internal sediment to diversion spreader channels, surface sedimentation and aggregation of the spreading field depth are most important effective attributes on the yield of floodwater spreading systems. these...

extended abstract   introduction the most important indicator of climate in a region is vegetation community. climate can be different over large areas, because of changes in vegetation community. vegetation influences weather and climate in its surrounding areas mostly by way of evapotranspiration and albedo so they play a role in the earth’s energy balance. these effects on the earth’s energy...

forest cover is one of the most effective factors in reducing flooding in northern iran, so that in recent years the destruction, land use changing and uncontrolled harvesting of forest areas, has greatly increased the number and magnitude of floods. so far, there have been few studies on forest hydrology in iran, particularly the northern hyrcanian forests. this study examines the impact of a ...