b a ckground: pediculosis capitis is cosmopolitan health problem. in addition to its physical problems, its psycho-logical effects especially on pupils are more important. this study was conducted to determine the pediculosis capitis among primary school pupils and also find out the role of probable related risk factors in urmia city, iran 2010. methods: 35 primary schools of urmia city accordi...

We introduce a new generalization of Alan Day’s doubling construction. For ordered sets L and K and a subset E ⊆ ≤L we define the ordered set L ?E K arising from inflation of L along E by K. Under the restriction that L and K are finite lattices, we find those subsets E ⊆ ≤L such that the ordered set L ?E K is a lattice. Finite lattices that can be constructed in this way are classified in term...

Our starting point is a very simple one, namely that of a set L4 of four mutually skew lines in PG(7, 2). Under the natural action of the stabilizer group G(L4) < GL(8, 2) the 255 points of PG(7, 2) fall into four orbits ω1, ω2, ω3, ω4, of respective lengths 12, 54, 108, 81. We show that the 135 points ∈ ω2 ∪ ω4 are the internal points of a hyperbolic quadric H7 determined by L4, and that the 8...

Recently the Ruelle-Perron-Fröbenius theorem was proved for Hölder potentials defined on the symbolic space Ω = MN, where (the alphabet) M is any compact metric space. In this paper, we extend this theorem to the Walters space W (Ω), in similar general alphabets. We also describe in detail an abstract procedure to obtain the Fréchetanalyticity of the Ruelle operator under quite general conditio...

We consider a second order linear equation with a time-dependent coefficient c(t) in front of the “elastic” operator. For these equations it is well-known that a higher spaceregularity of initial data compensates a lower time-regularity of c(t). In this paper we investigate the influence of a strong dissipation, namely a friction term which depends on a power of the elastic operator. What we di...

Lobe dynamics and escape from a potential well are general frameworks introduced to study phase space transport in chaotic dynamical systems. While the former approach studies how regions of phase space are transported by reducing the flow to a two-dimensional map, the latter approach studies the phase space structures that lead to critical events by crossing periodic orbit around saddles. Both...

We establish a relation between two uniform models of random k-graphs (for constant k ≥ 3) on n labeled vertices: H(k)(n,m), the random k-graph with exactly m edges, and H(k)(n, d), the random d-regular k-graph. By extending to k-graphs the switching technique of McKay and Wormald, we show that, for some range of d = d(n) and a constant c > 0, if m ∼ cnd, then one can couple H(k)(n,m) and H(k)(...

the aim of this study was investigation of the factors affecting the primary choice of consumers in food purchasing in mashhad city by applying cross section data of 201 households in 2012. in this study, 56, 30, and 14% of the consumers chose healthiness of food, price of food, and taste of food, respectively, as the primary preference in food purchase. results of applying multinomial logit mo...

background: dysmenorrhea is one of the most common medical problems in gynecology causing several problems in the personal and social life of women. this study was conducted to compare the effect of thymus vulgaris and ibuprofen on the treatment of primary dysmenorrhea methods: this clinical study was conducted on 84 students of babol university of medical sciences with primary dysmenorrhea. th...