The Padmakar-Ivan (PI) index of a graph G is the sum over all edges uv of G of the number of edges which are not equidistant from u and v. In this paper, the notion of vertex PI index of a graph is introduced. We apply this notion to compute an exact expression for the PI index of Cartesian product of graphs. This extends a result by Klavzar [On the PI index: PI-partitions and Cartesian product...

A questionnaire requiring respondents to rate the importance of key issues is the traditional data collection tool for investigating the key issues of Information Technology (IT) managers. Such an instrument does not force managers to confront the relationships between issues. Q-sort and interpretive structured modeling (ISM) force managers to consider the linkages among key issues. This articl...

By the time of Hippocrates the typical paroxysmal fever patterns of tertian (every 48 hours) and quartan (every 72 hours) fevers caused by malaria were known. Through the ensuing centuries, ancient Greek, Roman, and Persian physicians made additional contributions to the understanding of fevers. By the end of that era, there was a working definition of what constitutes a fever, the distinction ...

will suggest itself to you that such a comprehensive subject as Indian fevers could be touched on only in the slightest and most superficial manner, in the brief space accorded me. Instead, therefore, of endeavouring to wander discursively through the wide domain of Indian fevers generally, I shall attempt to limit my remarks to some few, select, points in the history of what is par excellence ...

This paper has a marked practical aspect. We wish to encourage and facilitate the use of Q methodology amongst psychologists interested in qualitative research. The paper duly answers a number of pertinent ‘how to do Q’ questions. Yet our primary intention is not to produce an exhaustive ‘how to do Q’ guide. In discussing issues of theory, method and interpretation in Q methodology, the main ai...

Article history: Received 28 March 2009 Received in revised form 16 May 2012 Accepted 3 June 2012 Available online 9 June 2012