Bar 1-Visibility Drawings of 1-Planar Graphs

A bar 1-visibility drawing of a graph $G$ is a drawing of $G$ where each vertex is drawn as a horizontal line segment called a bar, each edge is drawn as a vertical line segment where the vertical line segment representing an edge must connect the horizontal line segments representing the end vertices and a vertical line segment corresponding to an edge intersects at most one bar which is not an end point of the edge. A graph $G$ is bar 1-visible if $G$ has a bar 1-visibility drawing. A graph $G$ is 1-planar if $G$ has a drawing in a 2-dimensional plane such that an edge crosses at most one other edge. In this paper we give linear-time algorithms to find bar 1-visibility drawings of diagonal grid graphs and maximal outer 1-planar graphs. We also show that recursive quadrangle 1-planar graphs and pseudo double wheel 1-planar graphs are bar 1-visible graphs.Comment: 15 pages, 9 figure

What are the resourcing requirements for an Aboriginal and Torres Strait Islander primary health care research project?

Objective and importance: To explore the role of resourcing during an Aboriginal and Torres Strait Islander primary health care research project. Study type: Process evaluation using grounded theory approaches of a national Aboriginal and Torres Strait Islander research project (N = 500) named Getting it Right: the validation study. Methods: Qualitative semistructured interviews with 36 primary health care staff and 4 community members from 9 of 10 primary health care services involved in the research project. Interviews included questions about the resources needed to conduct the research project, including fexible reimbursement to participating services (allocated within services), human resources and reimbursement to research participants (vouchers). Qualitative data were triangulated with participant feedback, study administrative data and feld notes kept by the interviewer. Results: Three themes were identifed: 1) the infuence of reimbursement on participating services and the research project; 2) the infuence of human resources on the research project at participating services; and 3) the consequences of offering vouchers to reimburse research participants. Reimbursement was allocated to research expenses (human resources and logistics) or non-research expenses (service operations, equipment and conference attendance costs). Most services opted to offer vouchers to compensate participants for their time, which staff considered was appropriate recognition of participants’ contributions and facilitated recruitment. Some staff described some potential unintended negative consequences from offering vouchers, including creating a welfare mentality or creating problematic expectations. Conclusion: Primary health care research should have suffcient resourcing available, including human resource capacity, to achieve research targets. Research planning should include consideration of the existing commitments, priorities and human capacity needs of services and patients.Sara Farnbacha, Graham Geec, Anne-Marie Eadesa, John Robert Evanse, Jamie Fernandog, Belinda Hammond, Matty Simms, Karrina DeMasi, Nick Glozier, Maree L Hackett, on behalf of the Getting it Right Investigator

A FURTHER EXAMINATION OF THE PRICE AND VOLATILITY IMPACT OF STOCK DIVIDENDS AT EX-DATES *

We examine the price and volatility reaction around stock dividend ex-dates for an Australian sample, over the period January 1992 to December 2000. We find that price reaction around stock dividend ex-dates provides positive abnormal returns both prior, and subsequent, to the abolishment of par value of shares in July 1998. When we partitioned the sample into financial, industrial non-financial and mining firms, the price reaction is found to be positive and significant only for industrial non-financial companies. Volatility of daily returns for periods subsequent to ex-dates is significantly greater than corresponding periods prior to announcement dates, while cumulative raw returns subsequent to ex-dates are significantly lower than periods prior to announcement dates for industrial non-financial companies. The magnitude of the price reaction is statistically significantly related to an increase in the volatility of daily returns and to a reduction in cumulative raw returns subsequent to the ex-dates, for industrial non-financial companies. These findings support buying pressure hypothesis suggested by Dhatt et al. (1994, 1996 ). Copyright Blackwell Publishing Ltd/University of Adelaide and Flinders University 2005..