Technology-assisted learning systems are being developed at ever increasing rates, and the labels applied to such systems are growing with them. For example, not only do we have e-learning, but we also have hybrid learning, online learning, and mobile learning (m-learning), to mention only a few. Considering that technology is being incorporated in virtually all courses, this article uses the s...

a set $s$ of vertices in a graph $g=(v,e)$ is called a total$k$-distance dominating set if every vertex in $v$ is withindistance $k$ of a vertex in $s$. a graph $g$ is total $k$-distancedomination-critical if $gamma_{t}^{k} (g - x) < gamma_{t}^{k}(g)$ for any vertex $xin v(g)$. in this paper,we investigate some results on total $k$-distance domination-critical of graphs.

The eccentricity of a vertex $v$ is the maximum distance between $v$ and anyother vertex. A vertex with maximum eccentricity is called a peripheral vertex.The peripheral Wiener index $ PW(G)$ of a graph $G$ is defined as the sum ofthe distances between all pairs of peripheral vertices of $G.$ In this paper, weinitiate the study of the peripheral Wiener index and we investigate its basicproperti...

The edge version of Szeged index and vertex version of PI index are defined very recently. They are similar to edge-PI and vertex-Szeged indices, respectively. The different versions of Szeged and PIindices are the most important topological indices defined in Chemistry. In this paper, we compute the edge-Szeged and vertex-PIindices of some important classes of benzenoid systems.

a green low-cost and reproducible yeast mediated synthesis of silver nanoparticles is reported. the synthesis is performed at room temperature. x-ray and transmission electron microscopy analyses are performed to ascertain the formation of ag nanoparticles. nanoparticles almost spherical in shape having a size of 6-20 nm are found.

The vertex-edge Wiener index of a simple connected graph G is defined as the sum of distances between vertices and edges of G. Two possible distances D_1(u,e|G) and D_2(u,e|G) between a vertex u and an edge e of G were considered in the literature and according to them, the corresponding vertex-edge Wiener indices W_{ve_1}(G) and W_{ve_2}(G) were introduced. In this paper, we present exact form...

background : due to specific conditions in hospitals such as accumulation, existence of disable persons and patients, different and complex equipment, chemical and infectious substances, flammable materials and ionized radiations, safety precautions is essential to prevent the occurrence of incidents such as fire, electric shock hazard and exposure to excessive levels in hospitals. this was the...

background: the 21st century is faced with increase in challenges of urban population and aging. according to statistics, the old population in the world and in iran is increasing. obviously, their health promotion is the concern of the community and achieving it requires purposeful planning. being healthy means to feel good in social, mental, and physical dimensions (definition by the world he...