The irregularity of a simple undirected graph G was defined by Albertson [5] as irr(G) = ∑ uv∈E(G) |dG(u)− dG(v)|, where dG(u) denotes the degree of a vertex u ∈ V (G). In this paper we consider the irregularity of graphs under several graph operations including join, Cartesian product, direct product, strong product, corona product, lexicographic product, disjunction and symmetric difference. ...

School system in which classes are scheduled 1 week in the morning and the other in the afternoon, and in which students rotate schedule every week, fosters sleep irregularity. In this study, we examined morningness-eveningness of adolescents who were involved in such schedule of school time and explored relationship between their circadian preferences and sleep characteristics. A large sample ...

INTRODUCTION There is no consensus on the length of ECG tracing that should be recorded to represent adequate rate control in patients with atrial fibrillation (AFib). The purpose of the study was to examine whether heart rate measurements based on short-term ECGs recorded at different periods of the day may correspond to the mean heart rate and rate irregularity analyzed from standard 24-hour ...

An assignment of positive integer weights to the edges of a simple graph G is called irregular, if the weighted degrees of the vertices are all different. The irregularity strength, s(G), is the maximal weight, minimized over all irregular assignments. In this study, we show that s(G) c1 n / , for graphs with maximum degree n and minimum

Martin Bača et al. [2] introduced the problem of determining the total vertex irregularity strengths of graphs. In this paper we discuss how the addition of new edge affect the total vertex irregularity strength.

Conventional wisdom holds that productive morphology is regular morphology. Drawing evidence from French, we argue that the description of many lexeme formation processes is simplified if we hold that a productive rule may give rise to inflectionally irregular lexemes. We argue that the notion of a stem space allows for a straightforward description of this phenomenon: each lexeme comes equippe...

In vivo cortical neurons are known to exhibit highly irregular spike patterns. Because the intervals between successive spikes fluctuate greatly, irregular neuronal firing makes it difficult to estimate instantaneous firing rates accurately. If, however, the irregularity of spike timing is decoupled from rate modulations, the estimate of firing rate can be improved. Here, we introduce a novel c...