Making triangulations 4-connected using flips

We show that any combinatorial triangulation on n vertices can be transformed into a 4-connected one using at most floor((3n - 9)/5) edge flips. We also give an example of an infinite family of triangulations that requires this many flips to be made 4-connected, showing that our bound is tight. In addition, for n >= 19, we improve the upper bound on the number of flips required to transform any 4-connected triangulation into the canonical triangulation (the triangulation with two dominant vertices), matching the known lower bound of 2n - 15. Our results imply a new upper bound on the diameter of the flip graph of 5.2n - 33.6, improving on the previous best known bound of 6n - 30.Comment: 22 pages, 8 figures. Accepted to CGTA special issue for CCCG 2011. Conference version available at http://2011.cccg.ca/PDFschedule/papers/paper34.pd

B_d mixing and prospects for B_s mixing at D0

Measurement of the B_s oscillation frequency via B_s mixing analyses provides a powerful constraint on the CKM matrix elements. The study of B_d oscillations is an important step towards B_s mixing and a preliminary measurement of Delta m_d has been made with ~250 pb^-1 of data collected with the upgraded Run II D0 detector. Different flavor tagging algorithms have been developed and are being optimized for use on a large set of B_s mesons that have been reconstructed in different semileptonic decay modes.Comment: Poster presented at the XXIV Physics in Collisions Conference (PIC04), Boston, USA, June 2004, 4 pages, LaTeX, 2 eps figure

Computation of laminar heat transfer from gaseous plasmas in electromagnetic fields

Heat transfer analysis procedure is presented for two-temperature gaseous plasma. Analysis is based on laminar flow of singly-ionized, quasineutral plasma with variable properties. Sheath analysis is described for species in accelerating field, decelerating field, emitted from wall, and recombining at wall

HUD Homes: How they Can Promote Home Ownership and Reduce House Abandonment

For many, the American Dream still means owning a home. The home ownership rate in the U.S. fell in the fourth quarter of 2007 to its lowest level since the beginning of 2002--this from a record high in the middle of 2004. What is more alarming, however, is that the home owner vacancy rate went up 2.8 percent. The bulk of the vacant homes are foreclosed homes. Among such foreclosed homes are Department of Housing and Urban Development (HUD) homes that have come into HUD’s possession as a result of Federal Housing Administration (FHA) loan defaults