The Strong Dirac conjecture, open in some form since 1951 [5], is that every set of n points in R includes a member incident to at least n/2 − c lines spanned by the set, for some universal constant c. The less frequently stated dual of this conjecture is that every arrangement of n lines includes a line incident to at least n/2 − c vertices of the arrangement. It is known that an arrangement o...

A simplicial arrangement of pseudolines is a collection of topological lines in the projective plane where each region that is formed is triangular. This paper refines and develops David Eppstein’s notion of a kaleidoscope construction for symmetric pseudoline arrangements to construct and analyze several infinite families of simplicial pseudoline arrangements with high degrees of geometric sym...

We describe a linear-time algorithm that finds a planar drawing of every graph of a simple line or pseudoline arrangement within a grid of area O(n). No known input causes our algorithm to use area Ω(n ) for any > 0; finding such an input would represent significant progress on the famous k-set problem from discrete geometry. Drawing line arrangement graphs is the main task in the Planarity puz...

the effect of shoot pruning (2, 3 and 4 branches per plant) and fruit position selection (on main branch vs on main and lateral branches) on yield and qualitative characteristics of two greenhouse grown pepper (capsicum annuum l.) cultivars (torkal and paramo) was studied through a factorial experiment arranged in a completely randomized block design, of three replications. results indicated th...

in order to study the effect of row spacing and plant density on quantity and quality yield of soybean in weed competitive condition, a field experiment was carried out at research farm of yasuj agricultural college in summer of 2011. experiment arrangement was split factorial base on randomized complete block design with three replication. the main factor included weed ( in two levels of contr...

Measurement bias refers to systematic differences across subpopulations in the relation between observed test scores and the latent variant underlying the test scores. Comparisons of subpopulations with the same score on the latent variable can be expected to have the same observed test score. Measurement invariance is therefore one of the key issues in psychological testing. It has been establ...

In this study effects that are significant on the fuel consumption of F-4 aircrafts are analyzed by using different statistical methods and the results of those different methods are compared. The response variable of every possible combination of factors and interactions are analyzed to provide information about main effect(s) and interaction effect(s). MARS is applied in order to find the rel...

twenty eight lactating buffaloes were used in a completely randomized design with 2×2 factorial arrangement of four experimental diets including low protein–low energy (lp-le), low protein–high energy (lp-he), high protein–low energy (hp-le) and high protein–high energy (hp-he). results showed that the hp-he diet recorded the highest digestibility coefficients of cp, ee, nfe, nutritive values, ...