561 research outputs found

    Computation of Gutman Index of Some Cactus Chains

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    Let G be a finite connected graph of order n. The Gutman index Gut(G) of G is defined as {x,y}V(G)deg(x)deg(y)d(x,y)\sum_{\{x,y\}\subseteq V(G)}deg(x)deg(y)d(x, y), where deg(x) is the degree of vertex x in G and d(x, y) is the distance between vertices x and y in G. A cactus graph is a connected graph in which no edge lies in more than one cycle. In this paper we compute the exact value of Gutman index of some cactus chains

    Global oil risk price management in Iran and Russia

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    Oil is one of the most important sources of income for oil-exporting countries such as the Russian Federation and Iran, as well as the main raw material in the production process in oil-importing countries. Risks fluctuations in world oil prices can cause sovereign financial risks of instability in macroeconomic variables in both groups of oil exporting and importing countries. Negative shocks in world oil prices for countries such as Iran and Russia, whose economic structure is oriented towards oil and provides a significant part of the state budget through oil, could have significant consequences for the economies of these countries. Such fluctuations not only affect the economies of oil-importing countries, but are also one of the main causes of disruptions in the economies of oil-exporting countries. This study examines the government's management of risk fluctuations in world oil prices and its actions in Iran and Russia. The results of this study show that Iran and Russia, as sanctioned countries and oil exporters, have taken various measures to deal with these shocks, the most important of which is the creation of sovereign wealth funds in the two countries. In this article, the characteristics of national development funds in Iran and Russia are compared. The differences between Iran and Russia in risk management and the structure of these funds are shown

    On the roots of total domination polynomial of graphs, II

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    Let G=(V,E)G = (V, E) be a simple graph of order nn. The total dominating set of GG is a subset DD of VV that every vertex of VV is adjacent to some vertices of DD. The total domination number of GG is equal to minimum cardinality of total dominating set in GG and is denoted by γt(G)\gamma_t(G). The total domination polynomial of GG is the polynomial Dt(G,x)=i=γt(G)ndt(G,i)xiD_t(G,x)=\sum_{i=\gamma_t(G)}^n d_t(G,i)x^i, where dt(G,i)d_t(G,i) is the number of total dominating sets of GG of size ii. A root of Dt(G,x)D_t(G, x) is called a total domination root of GG. The set of total domination roots of graph GG is denoted by Z(Dt(G,x))Z(D_t(G,x)). In this paper we show that Dt(G,x)D_t(G,x) has δ2\delta-2 non-real roots and if all roots of Dt(G,x)D_t(G,x) are real then δ2\delta\leq 2, where δ\delta is the minimum degree of vertices of GG. Also we show that if δ3\delta\geq 3 and Dt(G,x)D_t(G,x) has exactly three distinct roots, then Z(Dt(G,x)){0,2±2i,3±3i2}Z(D_t(G,x))\subseteq \{0, -2\pm \sqrt{2}i, \frac{-3\pm \sqrt{3}i}{2}\}. Finally we study the location roots of total domination polynomial of some families of graphs.Comment: 10 pages, 5 figure

    Discovery of AZD3199, an inhaled ultralong acting β2 receptor agonist with rapid onset of action

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    A series of dibasic des-hydroxy β2 receptor agonists has been prepared and evaluated for potential as inhaled ultra-long acting bronchodilators. Determination of activities at the human β-adrenoreceptors demonstrated a series of highly potent and selective β2 receptor agonists that were progressed to further study in a guinea pig histamine-induced bronchoconstriction model. Following further assessment by; onset studies in guinea pig tracheal rings and human bronchial rings contracted with methacholine (guinea pigs) or carbachol (humans), duration of action studies in guinea pigs after intratracheal (i. t.) administration and further selectivity and safety profiling AZD3199 was shown to have an excellent over all profile and was progressed into clinical evaluation as a new ultra-long acting inhaled β2 receptor agonist with rapid onset of action
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