for a nite group g the commutativity degree denote by d(g) and dend: d(g) = jf(x; y)jx; y 2 g; xy = yxgj jgj2 : in [2] authors found commutativity degree for some groups,in this paper we nd commuta- tivity degree for a class of groups that have high nilpontencies.

heavy metal contamination around the national iranian lead and zinc company (nilz) in zanjan province was evaluated in this paper. collected data were used to appraise the degree of soil contamination and also the source of pollution in the study area based on geoaccumulation index (igeo), and enrichment factor (ef). the levels of fe, zn, cd and pb in the samples exceed those reported in litera...

Introduction: Photon contamination is a restriction on treatment with electron that increase dose to healthy tissue below the tumor. The aim of this study is to reduce the photon contamination using a magnet system. Materials and Methods: A mini-applicator equipped with two neodymium boron permanent magnets was designed which make it possible to adjust the d...

Total metals concentrations, Geoaccumulation index (Igeo), Pollution load index (PLI), degree of contamination (DC) and sediment quality guidelines (SQGs) were used to assess heavy metals contamination status and ecological risk in the sediments from the Libyan Mediterranean coast. The distribution pattern of heavy metals in the sediment follows the sequence: Fe>Pb>Mn>Ni>Zn>Cr>Cu>Co>Cd. Over th...

In insects, cleaning (grooming) of tarsal attachment devices is essential for maintaining their adhesive ability, necessary for walking on a complex terrain of plant surfaces. How insects obtain information on the degree of contamination of their feet has remained, until recently, unclear. We carried out friction force measurements on walking beetles Gastrophysa viridula (Coleoptera, Chrysomeli...

the contents of as, cd, cu and mo were determined in soil surrounding meyduk tailings dam based on 21 surface soil samples. assessment of toxic element pollution in studied soil samples needs knowledge of pre-anthropogenic metal concentration to act as a reference against which measured values could be compared. estimating the background values was executed by sampling rocks adjacent to soil sa...

Anthropogenic environmental changes are hypothesized as main reasons for animal species population declines. Heavy metals contamination is one of the worst threats to animals among human-caused threats. As most of the heavy metals bioaccumulate in organisms, analyzing concentrations of heavy metals in long living animals, such as turtles, would be very useful for biomonitoring of environmental ...