A clutter or antichain on a set defines a hypergraph. Matroid ports are a special class of clutters, and this paper deals with the diameter of matroid ports, that is, the diameter of the corresponding hypergraphs. Specifically, we prove that the diameter of every matroid port is at most 2. The main interest of our result is its application to secret sharing. Brickell and Davenport proved in 198...

In uncertain graphs, the existence of some edges is not predetermined. The diameter of an uncertain graph is essentially an uncertain variable, which indicates the suitability for investigation of its distribution function. The main focus of this paper is to propose an algorithm to determine the distribution function of the diameter of an uncertain graph. We first discuss the characteristics of...

We consider the mixing time of random walks on a graph G, using the eigenvalue gap to measure the mixing time. We attempt to bound the mixing time in terms of the diameter Diam of G. We show that, for the standard random walk, there exists a family of graphs with diameter 3 but mixing time Ω(n), and a family of trees with diameter 3 but mixing time Ω(n). The main result is a scheme for re-weigh...

Introduction: Foreign body inhalation in children is not uncommon, and may escape notice by the parents as well as the physicians, because of the lack of knowledge of the exact history and inconclusive radiographical findings. Methods: A retrospective analysis of airway foreign bodies in 132 children (80 males and 52 females) over a period of 20 years was conducted. Rigid bronchoscopy under gen...

BACKGROUND Paediatric tracheobronchial tumours are very rare, and pneumonectomy and lobectomy procedures are rarely indicated due to their surgical difficulties and high sequelae. Bronchoplastic techniques preserving lung parenchyma allow the resection and reconstruction of the main bronchi and carina. CASE PRESENTATION Here, we present a 6-year-old boy suffering from a carcinoid tumour of th...

A left completion pneumonectomy operation for primary lung cancer (left lower lobectomy) was complicated by sudden loss of ability to ventilate the patient via the double lumen endotracheal tube. The problem could not be overcome by the anesthesiologist. In the face of impending cardiorespiratory arrest a single lumen tube was introduced through an incision in the left main bronchus through to ...

Copyright © 2013, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Published by Kowsar Corp. This is an openaccess article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original wor...

In this letter, the uniform 4H silicon carbide (SiC) mesopores was fabricated by pulsed electrochemical etching method. The length of the mesopores is about 19 μm with a diameter of about 19 nm. The introduction of pause time (T off) is crucial to form the uniform 4H-SiC mesopores. The pore diameter will not change if etching goes with T off. The hole concentration decreasing at the pore tips d...