We develop a time-optimal O(mn)-time algorithm for the problem of constructing the subtree prune-regraft (SPR) graph on a collection of m phylogenetic trees with n leaves. This improves on the previous bound of O(mn). Such graphs are used to better understand the behaviour of phylogenetic methods and recommend parameter choices and diagnostic criteria. The limiting factor in these analyses has ...

ImageS region containing bony defects of approximately 2×3 cm using a regraft from amputated soft tissue of the forehead. Thus, we obtained a good treatment outcome without using previously reported treatment methods such as a tie-over dressing although vascular anastomosis could not be performed in our case. Here, we report on our treatment outcomes. In July 2009, a 52-year-old woman visited a...

BACKGROUND Repeat penetrating keratoplasty is quite often required as there is high chance of failure of the primary graft particularly in the developing world. We planned a study to analyze the indications and outcome of repeat penetrating keratoplasty in a tertiary care centre in India. METHODS A retrospective analysis of all the patients who underwent repeat penetrating keratoplasty, betwe...

purpose : to evaluate indications, risk factors and outcome of repeat penetrating keratoplasty (pkp) at a tertiary referral eye care center methods : in this retrospective study, medical chart of patients who underwent repeat pkp at labbafinejad medical center between january 2004 and december 2009 were reviewed. results : a total of 1,859 corneal transplantations were performed on 1,624 eyes d...

We provide a unifying view on the structure of maximum (acyclic) agreement forests of rooted and unrooted phylogenies. This enables us to obtain linearor O(n log n)-time 3-approximation and improved fixed-parameter algorithms for the subtree prune and regraft distance between two rooted phylogenies, the tree bisection and reconnection distance between two unrooted phylogenies, and the hybridiza...

complications than depression at the site of injury (Fig. 1B). This case shows that even though the skin defect was greater than 1 cm, a substantial period of time elapsed prior to the surgery, and the period of ischemic condition was prolonged, we were able to perform a regraft from the amputated tissue instead of vessel anastomosis. We obtained such a successful treatment outcome that entire ...

We give a 2-approximation algorithm for the Maximum Agreement Forest problem on two rooted binary trees. This NP-hard problem has been studied extensively in the past two decades, since it can be used to compute the Subtree Prune-and-Regraft (SPR) distance between two phylogenetic trees. Our result improves on the very recent 2.5-approximation algorithm due to Shi, Feng, You and Wang (2015). Ou...

For two rooted phylogenetic trees T and T ′, the rooted subtree prune and regraft distance between T and T ′ has often been used as a replacement for the hybridization number of T and T ′. However, Baroni et al. [1] constructed particular instances that showed both the difference and the ratio between this number and distance can be arbitrarily large. In this note, we show that the difference a...