Mathematics

  2010 FEB 2 - (VerticalNews.com) -- According to recent research from Serbia, "A new molecular-structure descriptor G A(2), belonging to the class of geometric-arithmetic indices, is considered."

  "It is closely related to the Szeged and vertex PI indices. The main properties of G A(2) are established, including lower and upper bounds," wrote G. Fathtabar and colleagues, University of Kragujevac.

  The researchers concluded: "The trees with minimum and maximum G A(2) are characterized. ...read more

  2010 FEB 2 - (VerticalNews.com) -- According to recent research from Istanbul, Turkey, "The operator involving problems are mostly handled by using the matrix representations of the operators over a finite set of appropriately chosen basis functions in a Hilbert space as long as the related problem permits. The algebraic operator which multiplies its operand by a function is the focus of this work."

  "We deal with the univariate case for simplicity. We show that a rapidly converging scheme can be constructed by defining an appropriate fluctuation operator which projects, in fact, to the complement of the space spanned by appropriately chosen finite number of basis functions," wrote M. Demiralp and colleagues, Istanbul Technical University ...read more

  2010 FEB 2 - (VerticalNews.com) -- "In an ecosystem some populations not only consume the resource but also contribute themselves to the resource after senescence and other deaths and considered another source of resource. In view of these facts and based on whether the population individual is capable of reproduction, a single-species chemostat model with age structure and the contribution to resource is formulated and analyzed," scientists in Tianjin, People's Republic of China report ...read more