We analyze the vector magnetograms in several well-developed active regions obtained at Huairou Solar Observing Station, National Astronomical Observatories of China, at Mees Solar Observatory, University of Hawaii, and at National Astronomical Observatory of Japan. It is found that there is a basic agreement on the transversal fields among these magnetographs. The observational error (mutual d...

A P4-transversal of a graph G is a set of vertices T which meets every P4 of G. A P4transversal T is called stable if there are no edges in the subgraph of G induced by T . It has been previously shown by Hoàng and Le that it is NP -complete to decide whether a comparability (and hence perfect) graph G has a stable P4-transversal. In the following we show that the problem is NP -complete for ch...

OBJECTIVES Ideal occlusion is a hypothetical standard based on teeth's morphological relationships and is characterised by perfection in anatomy and dental position, mesiodistal contacts, arch alignment and dental interdigitation. This investigation was aimed at determining the epidemiological profile of dental occlusion of children attending urban and rural public schools in Envigado during th...

We continue the investigation of validity of Hall’s theorem in the case of the Loeb space L(H) of an internal, uniformly distributed, hyperfinite measure space H = (Ω,A, μ) initiated in1992 by the author. Some new classes of graphs are introduced for which the measure theoretic version of Hall’s theorem still holds.

Contact structures on manifolds and Legendrian and transversal knots in them are very natural objects, born over two centuries ago, in the work of Huygens, Hamilton and Jacobi on geometric optics and work of Lie on partial differential equations. They touch on diverse areas of mathematics and physics, and have deep connections with topology and dynamics in low dimensions. The study of Legendria...

The concept of ‘topological right transversal’ is introduced to study right transversals in topological groups. Given any right quasigroup S with a Tychonoff topology T , it is proved that there exists a Hausdorff topological group in which S can be embedded algebraically and topologically as a right transversal of a subgroup (not necessarily closed). It is also proved that if a topological rig...

Various methods for sound synthesis based on physical models have been presented. They start from a continuous model for the vibrating body, given by partial differential equations (PDEs), and employ proper discretization in time and space. Examples are wave guide models or finite difference models. A different approach is presented here. It is based on a multidimensional transfer function mode...

Background: Heat cured acrylic resin is the most widely used material in the manufacture ofdenture base, but has mechanical properties weakness (transversal strength and impact strength). Alternative to increase the mechanical properties of acrylic resin is the utilization of reinforcing fibre that is polyethylene fibre that has advantage such as good aesthetic, easy to manipulate and increase ...