In this study, we give the relationships between the conical curvatures of ruled surfaces generated by the unit vectors of the ruling, central normal and central tangent of a ruled surface in the Euclidean 3-space E^3. We obtain differential equations characterizing slant ruled surfaces and if the reference ruled surface is a slant ruled surface, we give the conditions for the surfaces generate...

We propose a novel representation of cosmic microwave anisotropy maps, where each multipole order , is represented by , unit vectors pointing in directions on the sky and an overall magnitude. These ‘‘multipole vectors and scalars’’ transform as vectors under rotations. Like the usual spherical harmonics, multipole vectors form an irreducible representation of the proper rotation group SO(3). H...

From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi fro...

Petri net (PN) as a graphical and mathematical formalism has extensively been used for the modeling, control and analysis of discrete event systems and it has been recognized as flexible modeling technique because it is well suited for modeling the multifarious constraints. This paper focuses on the recent developments in the area of linear algebraic techniques for the PN models for systems. Th...

Much research has been done in the area of multilevel database systems, especially in the security area and accelerating queries. In this paper, we present BVA, which is based on bit vectors to accelerate queries in multilevel secure database systems. As its predecessor (BVA), the BVA algorithm follows the classic Sea View Model, but it recovers query output from single-level relations in a fas...

The Japanese encephalitis virus (JEV), an arthropod-born Flavivirus, is the major cause of viral encephalitis, responsible for 10,000-15,000 deaths each year, yet is a neglected tropical disease. Since the JEV distribution area has been large and continuously extending toward new Asian and Australasian regions, it is considered an emerging and reemerging pathogen. Despite large effective immuni...