the degree of aromaticity of mono-substituted derivatives of benzene has beeninvestigated using a new index based on electric field gradient index, by using two mechanicalquantum methods with gaussian 03. two different basis sets have applied to study and theresults compared. this strategy has demonstrated that, due to violation of symmetry in have pisystems,how the degree of aromaticity can ha...

the reciprocal degree distance (rdd)‎, ‎defined for a connected graph $g$ as vertex-degree-weighted sum of the reciprocal distances‎, ‎that is‎, ‎$rdd(g) =sumlimits_{u,vin v(g)}frac{d_g(u)‎ + ‎d_g(v)}{d_g(u,v)}.$ the reciprocal degree distance is a weight version of the harary index‎, ‎just as the degree distance is a weight version of the wiener index‎. ‎in this paper‎, ‎we present exact formu...

Bell's degree-variance Var$!{}_{B}$ for a graph $G$, with the degree sequence ($d_1,d_2,cdots,d_n$) and size $m$, is defined as$Var!_{B} (G)=frac{1}{n} sum _{i=1}^{n}left[d_{i} -frac{2m}{n}right]^{2}$.In this paper, a new version of the irregularity measures of variance-type, denoted by $Var_q$, is introduced and discussed. Based on a comparative study, it is demonstrated that the n...

soil contamination significantly reduces environmental quality and affects human health. to investigate and assess the effects of land use on the concentrations of some heavy metals in surface soils of golestan province, 227 soil samples (0-60 cm) were collected from three types of land uses including agricultural lands, natural, and industrial areas. the total metals and metalloids (cr, se, as...

Model credibility index is defined to be a sample size under which the power of rejection equals 0.5. It applies goodness-of-fit testing thinking and uses a one-number summary statistic as an assessment tool in a false model world. The estimation of the model credibility index involves a bootstrap resampling technique. To assess the consistency of the estimator of model credibility index, we in...