Abstract Introduction Prior studies of patients with obstructive sleep apnea (OSA) show racial differences in clinical presentation. When compared White patients, Black present more severe OSA and greater sleepiness. Racial upper airway collapsibility could explain these differences. Here, we investigated whether mean positive pressure (PAP) levels, a clinically accessible measure collapsibilit...

Methods This is a cross-sectional study conducted during 2015 in an Italian ICU. We included adult patients with a Central Venous catheter without cerebral ischemia or bradycardia. Ultrasound images of IJV and IVC diameters at endexpiration (IJVDmax, IVCDmax) and at end-inspiration (IJVDmin, IVCDmin) were obtained with the patient supine using a 5-10 MHz and a 1-5 MHz probe (General Electric )....

In this paper we derive conditions on the internal wear process under which the resulting time-to-failure model will be of the simple collapsible form (Oakes, 1995, Duchesne and Lawless, 2000) when the usage accumulation history is available. We suppose that failure occurs when internal wear crosses a certain threshold and/or a traumatic event causes the item to fail (Cox, 1999 and Bagdonavičiu...

A simplicial complex K is called d-representable if it is the nerve of a collection of convex sets in R; K is d-collapsible if it can be reduced to an empty complex by repeatedly removing a face of dimension at most d − 1 that is contained in a unique maximal face; and K is d-Leray if every induced subcomplex of K has vanishing homology of dimension d and larger. It is known that d-representabl...

Consensus in cladistics is reviewed. Consensus trees, which summarize the agreement in grouping among a set of cladograms, are distinguished from compromise trees, which may contain groups that do not appear in all the cladograms being compared. Only a strict or Nelson tree is an actual consensus. This distinction has implications for the concept of support for cladograms: only those branches s...