SummaryLeaf dark respiration (R dark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in R dark .Area-based R dark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8-28°C). By contrast, R dark at a standard T (25°C, R dark 25 ) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher R dark 25 at a given photosynthetic capacity (V cmax 25 ) or leaf nitrogen concentration ([N]) than species at warmer sites. R dark 25 values at any given V cmax 25 or [N] were higher in herbs than in woody plants.The results highlight variation in R dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R dark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs).

For over three decades, the questions of how and why an organization diversifies into related and unrelated businesses have drawn the attention of strategy scholars. However, explanations of unrelated diversification have been less than clear. A conceptual model of unrelated diversification is thus proposed. In drawing on Penrose's (1959) resource based approach, unrelated diversification is explained by an organization's 'three pillars', which consist of its strength of dynamic capabilities, absorptive capacity, and weak ties. The role of the three pillars is to discover new resource applications or uses in conditions of market failure that are characterized by 'incomplete' markets. A novel feature of this model is that an organization can diversify more broadly than predicted by Penrose (1959) and other modern resource-based approaches (Teece et al., 1997). Furthermore, unrelated diversification can be beneficial. This study also offers suggestions to measure the three pillars; its contributions and implications are discussed as well. Copyright Blackwell Publishing Ltd 2007.

Suboptimal conditions of washing, drying, and storage contributed to the massive linen contamination and the outbreak of zygomycosis.