We develop a new model that simultaneously captures two principal sources of heterogeneity: variation across segments of consumers and variation across clusters of products. We focus on the recorded music industry as a managerial context, and construct a flexible duration-time model that can be used to capture the dynamic purchase patterns across a broad portfolio of different albums. Our basic...

Before a president practically begins his four-year term of office in Iran, a formal inaugural ceremony is held in the parliament. Being attended by national dignitaries and representatives from other countries, the inauguration of Iran's seventh president, Hasan Rouhani, was spectacular in several respects. The current study aimed at investigating the generic structure and rhetorical moves tha...

‎‎In the category of Mordell curves (E_D:y^2=x^3+D) with nontrivial torsion groups we find curves of the generic rank two as quadratic twists of (E_1), ‎and of the generic rank at least two and at least three as cubic twists of (E_1). ‎Previous work‎, ‎in the category of Mordell curves with trivial torsion groups‎, ‎has found infinitely many elliptic curves with ...

numerical taxonomy and seed storage protein analysis of hyoscyamus species of iran was carried out with the aim to illustrate species inter-relationship and to check the sub-generic taxonomic treatment proposed for the genus. cluster analysis of morphological and protein data grouped the species in three separate clusters which supports the relationships of h. niger with h. reticulatus and h. k...

BACKGROUND Generic drugs are considered therapeutically equivalent to their original counterparts and lower in acquisition costs. However, the overall impact of generic substitution (GS) on global clinical and economic outcomes has not been conclusively evaluated. OBJECTIVE To test whether (1) generics and original products yield the same health outcomes, and (2) generic therapies save econom...

In today’s competitive world, there are several strategies to deal with the fast changing environment, among which New product development (NPD) is a common strategy. However, almost half of the resources that companies devote to NPD are spent on products that may fail. This issue is particularly highlighted in the pharmaceutical industry mainly because of a long development-time, low success r...