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We empirically examine whether firms engage in a dynamic rebalancing of their capital structures while allowing for costly adjustment. We begin by showing that the presence of adjustment costs has significant implications for corporate financial policy and the interpretation of previous empirical results. After confirming that financing behavior is consistent with the presence of adjustment costs, we find that firms actively rebalance their leverage to stay within an optimal range. Our evidence suggests that the persistent effect of shocks on leverage observed in previous studies is more likely due to adjustment costs than indifference toward capital structure.

We are living in the post-information age, the era of so-called 'Big Data'. It is a practical possibility for corporations to report, chart and analyse every action, transaction and click that happens inside and outside their business. In Decision Sourcing Roberts and Pakkiri examine what this means to organisational decision making. They explode the myth that good decisions need only be informed ones through an examination into how business really make choices. They lay bare the poverty of decision making processes in today's corporate world and offer fresh and fascinating insight into how social tools are providing new sources of information, how they are challenging hierarchy and how they are providing opportunities for growth and agility through aligned and inclusive decision making. This book is for those organisations that want to get beyond the corporate Facebook account and are ready for the next bold step. It is for those businesses that want to engage their workforce and their customers in collaborative relationships that are at the heart of the successful social enterprise.

Most mammals have two types of cone photoreceptors, which contain either medium wavelength (M) or short wavelength (S) opsin. The number and spatial organization of cone types varies dramatically among species, presumably to fine-tune the retina for different visual environments. In the mouse, S-and M-opsin are expressed in an opposing dorsal-ventral gradient. We previously reported that cone opsin patterning requires thyroid hormone β2, a nuclear hormone receptor that regulates transcription in conjunction with its ligand, thyroid hormone (TH). Here we show that exogenous TH inhibits S-opsin expression, but activates M-opsin expression. Binding of endogenous TH to TRPβ2 is required to inhibit S-opsin and to activate M-opsin. TH is symmetrically distributed in the retina at birth as S-opsin expression begins, but becomes elevated in the dorsal retina at the time of M-opsin onset (postnatal day 10). Our results show that TH is a critical regulator of both S-opsin and M-opsin, and suggest that a TH gradient may play a role in establishing the gradient of M-opsin. These results also suggest that the ratio and patterning of cone types may be determined by TH availability during retinal development.

14-3-3 proteins function as regulators of a wide range of target proteins in all eukaryotes by effecting direct protein-protein interactions. Primarily, interactions between 14-3-3 proteins and their targets are mediated by phosphorylation at specific sites on the target protein. Hence, interactions with 14-3-3s are subject to environmental control through signalling pathways which impact on 14-3-3 binding sites. Because 14-3-3 proteins regulate the activities of many proteins involved in signal transduction, there are multiple levels at which 14-3-3 proteins may play roles in stress responses in higher plants. In this article, we review evidence which implicates 14-3-3 proteins in responses to environmental, metabolic and nutritional stresses, as well as in defence responses to wounding and pathogen attack. This evidence includes stress-inducible changes in 14-3-3 gene expression, interactions between 14-3-3 proteins and signalling proteins and interactions between 14-3-3 proteins and proteins with defensive functions.

By the end of January 2001, all NYSE stocks had converted their price quotations from 1/8s and 1/16s to decimals. This study examines the effect of this change in price quotations on ex-dividend day activity. We find that abnormal ex-dividend day returns increase in the 1/16 and decimal pricing eras, relative to the 1/8 era, which is inconsistent with microstructure explanations of ex-day price movements. We also find that abnormal returns increase in conjunction with a May 1997 reduction in the capital gains tax rate, as they should if relative taxation of dividends and capital gains affects ex-day pricing.

Increasing demand to conserve biodiversity in managed forests necessitates better understanding of the mpacts of forestry practices on the species-rich herbaceous layer. We compared composition and diversity of understory vegetation, environmental features, and stand structure of forests in New Brunswick, Canada, under four different management scenarios, including: young (24-66 yr) naturally regenerated forests and conifer plantations (19-64 yr) established after clear-cutting, mature (77-100 yr) naturally regenerated forests originating from natural disturbance (insect defoliation), and old-field plantations (31-77 yr) established on abandoned agricultural fields. The objectives were to determine how plant composition, forest structure, and microenvironment differed among stand types and which environmental or structural features were related to understory species. Detrended correspondence analysis (DCA) and multiresponse permutation procedure (MRPP) indicated that stand types differed in species composition and environments. Plantations were significantly lower in density of snags, deciduous canopy cover, and leaf substrate, and higher in coniferous canopy cover and needle, twig, and moss substrates than the natural stands. Old-field plantations had less cover of pits and mounds than all other stand types. Mature natural stands contained the greatest amount of coarse woody debris (CWD) in all decay classes and snags >14 cm diameter, and the lowest density of trees >5 cm diameter and moss cover. Canonical correspondence analysis (CCA) showed that species in both natural stand types are associated with decayed CWD, deciduous cover, and leaf substrate. Species in cutover plantations were associated with coniferous cover and needle substrate. Species composition in old-field plantations was distinct, with the lowest species richness and diversity of all stand types. We present a conceptual model illustrating the initial direct effects of previous land use and harvesting or postharvest treatments and the subsequent indirect effects associated with plantation or natural stand development on environmental features and understory vegetation. We recommend extending plantation harvest cycles to facilitate reestablishment and expansion of plant populations and maintaining diverse tree canopy composition, coarse woody debris, and pit and mound topography to sustain critical habitat for vascular understory plant species in managed forests.

The objectives of this paper are to (1) review existing diversity models, (2) identify principles that explain patterns of plant species diversity, (3) discuss implications for forest management, and (4) identify research needs. Many current theories cast disturbance as the key player in maintaining species diversity by preventing competitive dominance of one or a few species. Equilibrium and nonequilibrium theories alike agree that maximum diversity should occur at intermediate size, frequency, and intensity of disturbance. These models do not adequately predict patterns at all spatial scales or across community types. A mechanistic theory is needed to explain diversity patterns at the patch, stand, and landscape scales, as well as across site quality and successional gradients. Such a theory should be based upon the interaction between species' life-history characteristics and the nature of disturbance. New research is needed in the following areas: identifying disturbance-life-history interactions, particularly with respect to the short-term and long-term effects of disturbance; quantifying patch diversity and determining its relationship with species diversity; determining relationships between species diversity and structural and functional diversity; and identifying appropriate standards of comparison for managed stands. Comparative studies in different ecosystem types, such as boreal and tropical forests, should be encouraged to help clarify the relative importance of processes that influence diversity.

We examined the composition of understory vascular plant species in managed forests to determine how life-history attributes influence plant response to disturbance. Forest types investigated were plantations on old fields (31-77 years old, n = 6), plantations on cutover land (19-64 years old, n = 8), young forests naturally regenerated after clear-cutting (27-66 years old, n = 6), and mature natural forests with no recent harvesting activity (80-100 years old, n = 6). Species were categorized by habitat preference (forest, intermediate, disturbed), growth form (12 categories), and life form (15 categories). Forest-habitat species dominated both natural stand types, whereas disturbed-habitat species dominated both plantation types. Mature natural stands contained higher frequency and cover of many herb growth forms, and cutover plantations contained higher values for shrubs. Old-field plantations contained low values for all growth forms. Two life forms, geophytes and rosette hemicryptophytes, were not well represented in either plantation type. All plant functional groups were present in each stand type, suggesting that differences among stand types occur as shifts in the relative abundances of functional groups. We hypothesize that some species may be at risk of local extirpation in plantations because of their limited growth rates and reproductive characteristics.

Fusicoccin (FC) is a fungal toxin that activates the plant plasma membrane H+-ATPase by binding with 14-3-3 proteins, causing membrane hyperpolarization. Here we report on the effect of FC on a gene-for-gene pathogen-resistance response and show that FC application induces the expression of several genes involved in plant responses to pathogens. Ten members of the FC-binding 14-3-3 protein gene family were isolated from tomato (Lycopersicon esculentum) to characterize their role in defense responses. Sequence analysis is suggestive of common biochemical functions for these tomato 14-3-3 proteins, but their genes showed different expression patterns in leaves after challenges. Different specific subsets of 14-3-3 genes were induced after treatment with FC and during a gene-for-gene resistance response. Possible roles for the H+-ATPase and 14-3-3 proteins in responses to pathogens are discussed.

Most work on the disturbance ecology of North American forests has focused on the tree canopy and woody understory, with little consideration of the herbaceous layer. Understanding how this species-rich and ecologically important layer responds to natural disturbances is needed as a guide for conservation. As a framework for this review, selected natural disturbances common to North American forests are evaluated in terms of a three-axis model of disturbance severity: percentage of tree canopy removed, percentage of understory vegetation removed, and percentage of forest floor and soil removed or disrupted. Eight factors, which control herbaceous-layer response, are linked to the three axes; these factors vary in dominance, depending on disturbance type and severity. The relative importances of different species' regeneration mechanisms also vary along severity gradients. The disturbance-severity model, along with the linked response factors and regeneration mechanisms, provide a framework for evaluating impacts of both natural and anthropogenic disturbances. Long-term studies of herbaceous-layer response to disturbance are needed, particularly mechanistic studies that focus on the relative importance of the eight factors controlling response. The conceptual model proposed herein needs to be tested across the full spectrum of severity levels. Finally, comparisons between natural and anthropogenic disturbances are needed. [PUBLICATION ABSTRACT] Key words: disturbance, forests, herbaceous layer, life-history characteristics, succession, understory.