A topological index plays an important role in characterising various physical properties, biological activities, and chemical reactivities of a molecular graph. The Hosoya polynomial is used to evaluate the distance-based indices such as Wiener index, hyper-Wiener Harary Tratch – Stankevitch Zefirov index. In present study, we determine closed form for third type chain hex-derived network dime...

the chromatic number of a graph g, denoted by χ(g), is the minimum number of colors such that g can be colored with these colors in such a way that no two adjacent vertices have the same color. a clique in a graph is a set of mutually adjacent vertices. the maximum size of a clique in a graph g is called the clique number of g. the turán graph tn(k) is a complete k-partite graph whose partition...

Biodiversity plays a crucial role in stability and productivity of natural ecosystem. The main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. Therefore, fifty different Land Unit Tracts (LUT) were identified in Khod-Neuk basin, Yazd province, Iran, in 2010. Vegetation and soil samples were taken in th...

Abstract. A subgraph H of a graph G is gated if for every x ∈ V (G) there exists a vertex u in H such that dG(x, v) = dG(x, u) + dG(u, v) for any v ∈ V (H). The gated amalgam of graphs G1 and G2 is obtained from G1 and G2 by identifying their isomorphic gated subgraphs H1 and H2. Two theorems on the Wiener index of gated amalgams are proved. Several known results on the Wiener index of (chemica...

Both fertilizer and plant species richness may affect the soil nematode community. However, influence of weed interaction is unclear. Nematode abundance biodiversity in wheat plots treated with nitrogen, phosphate potassium addition (0, 1, 2 4 levels) were investigated a long-term microcosm experiment established 2010 at Kaifeng, China. The results demonstrated that treatment increased total ne...

the predatory mites of suborder prostigmata are important natural enemies of spider mites. in this study abundance and biodiversity of predatory mites of super families of raphignathoidea, bdelloidea and erythraeoidea in pomefruit orchards of mashhad) educational orchard of agricultural college of ferdowsi unuversity of mashhad, agricultural research centre of torogh and laeen, torghabe and sha...