background: this study set out to evaluate the utility of cerebrovascular virtual non-contrast (vnc) scans. materials and methods: conventional non-contrast (cnc) and dual-energy computed tomography angiography (de-cta) head scans were conducted on 100 subjects, of which 46 were normal, 15 had parenchymal hematomas of the brain, 13 had ischemic infarction, 22 had tumors, and 4 had calcified les...

In this paper, we firstly show that the $N$-dual operation of the right residual implication, which is induced by a left-conjunctive right arbitrary $vee$-distributive left semi-uninorm, is the right residual coimplication induced by its $N$-dual operation. As a dual result, the $N$-dual operation of the right residual coimplication, which is induced by a left-disjunctive right arbitrary $wedge...

the aim of this study was to compare the effects of three types of balancetraining: single task, dual task under fixed priority instructional set (fp) and dualtask under a variable priority instructional set (vp) on the balance of the elderly.the participants were 36 elderly over 65 years old from kerman province whowere randomly divided into three groups (each 12 subjects) based on burg pretes...

in a novel dual bed reactor fischer-tropsch synthesis was studied by using two diffrent cobalt catalysts. an alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a rutenuim promoted cobalt catalyst in the second bed. the activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed react...

A Heyting algebra is a distributive lattice with implication and a dual $BCK$-algebra is an algebraic system having as models logical systems equipped with implication. The aim of this paper is to investigate the relation of Heyting algebras between dual $BCK$-algebras. We define notions of $i$-invariant and $m$-invariant on dual $BCK$-semilattices and prove that a Heyting semilattice is equiva...

we study the notion of bounded approximate connes-amenability for‎ ‎dual banach algebras and characterize this type of algebras in terms‎ ‎of approximate diagonals‎. ‎we show that bounded approximate‎ ‎connes-amenability of dual banach algebras forces them to be unital‎. ‎for a separable dual banach algebra‎, ‎we prove that bounded‎ ‎approximate connes-amenability implies sequential approximate...

A dual-band artificial magnetic material and then a dual-band double-negative metamaterial structure based on symmetric spiral resonators are presented. An approximate analytical model is used for the initial design of the proposed structures. The electromagnetic parameters of the proposed metamaterial structure retrieved using an advanced parameter retrieval method based on the causality princ...