Theodore Motzkin proved, in 1936, that any polyhedral convex set can be expressed as the (Minkowski) sum of a polytope and a polyhedral convex cone. This paper provides five characterizations of the larger class of closed convex sets in finite…

Serotiny, or delayed seed dispersal, is common in fluctuating environments because it hedges the risks of establishment. Mammillaria pectinifera (Cactaceae) facultatively expels fruits in the year they are produced or retains them to disperse the seed over several years. We…

Purpose – Many international retirement migrants are amenity movers undertaking the first move in the late life course model of migration. The purpose of this paper is to examine second moves within the retirement destination community to test whether the…

Knowledge of the population dynamics of tropical trees has expanded considerably in the past 20 years. An important observation deriving from these investigations is the confirmation that population behaviour varies both in time and space. A tool recently developed to…

In this paper we analyze the growth and early survival of two congeneric columnar cacti: the rare Neobuxbaumia macrocephala (with low population densities and a narrow distribution range), and the relatively common Neobuxbaumia mezcalaensis (with dense populations and a broader…

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We have determined “effective” Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties.…

Information technology (IT) governance is identified as an organizational skill of great importance to the strategic alignment and delivery of value through information technology (IT). Implementing IT governance, however, is a challenge to organizations. This paper aims to demonstrate the…

What is the relative importance of forest successional age, environmental heterogeneity, landscape structure and spatial structure of sampling sites on ?-diversity of tropical dry forests (TDF)? How do the magnitude of ?-diversity and the relative influence of factors, processes and…

Comprehensive information on species distribution and species composition patterns of plant communities is required for effective conservation and management of biodiversity. Remote sensing offers an inexpensive means of attaining complete spatial coverage for large areas, at regular time intervals, and…