The impact of financing constraints on investment.

This thesis is an empirical and theoretical analysis of the impact of financing constraints on firm-level investment behaviour. Its primary objectives are to model this impact, and to test the restrictions these models place on the data. Chapter 1 contains a discussion of these themes, and provides an overview of the thesis. Chapter 2 addresses the empirical question of whether innovative firms are financially constrained. To answer this question, several structural investment equations are tested, and the sensitivity of physical investment expenditures to internal finance is compared across innovative and non-innovative firms. The investment expenditures of innovative firms are found to be more sensitive to cash flow than those of non-innovative firms. These results support the hypothesis that innovative firms are financially constrained. The third chapter builds a theoretical model to explain a widely reported fact in the inventory literature, which is that the variance of production exceeds the variance of sales. This fact contradicts a prediction of the standard Linear-Quadratic model of inventory investment, and for this reason is often referred to as the "excess variance of production" puzzle. In this chapter, a model of inventory investment is built. It is shown that when financing constraints are imposed on the model, it can explain the excess variance of production puzzle. In the absence of these constraints, the model does not deliver this result. The fourth chapter returns to the theme of identifying financially constrained firms. A weakness of existing tests of financing constraints is that they are not both direct and structural. This chapter addresses that criticism by constructing a model of investment from which is derived a simple and direct, structural test of the null hypothesis that a group of firms is financially constrained. The test is implemented on a panel of U.S. manufacturing firms. The results support the findings of existing tests

The State-of-the-Art Questionnaire on Applied Systems Analysis: A Report on the Responses

This publication is the second report by the Survey Project on the structure and content of a proposed Series of monographs and a Handbook to survey the state-of-the-art of applied systems analysis. In the first report (RR-76-16, Systems Analysis: An Outline for the State-of-the-Art Survey Publications, July 1976), we presented a revised outline and current guidelines for the Survey Project publication program; in the present document, the sequel. we discuss the response to a questionnaire -- distributed widely throughout the systems analyst community -- upon which our revised outline is based. This report should be of interest to the questionnaire respondents, and to a wider audience as well. in that it reflects what some 160 analysts and others associated with systems analysis think about systems analysis, what they consider to be vital and important in this area, and what they think to be peripheral or of minor relevance

Systems Analysis: An Outline for the State-of-the-Art Survey Publications

IIASA plans to organize, commission, and publish a Series of volumes and a Handbook to survey the international state-of-the-art of applied systems analysis. This report provides the Survey Project's explication of the concept of applied systems analysis; it describes in detail the proposed Series and Handbook, including purpose, audience, international character, level of presentation, authors, reviewers, and remuneration policies. An outline spanning the field of interest of applied systems analysis is designed to help prospective authors with the choice of topics. Guidelines are provided for the acceptability of volumes for the Series, and suggestions for prospective authors on the preparation of prospectuses (outlines) for Series monographs are included. These prospectuses are submitted to the Editorial Board and special liaison committees established in each of IIASA's National Member Organizations. A summary checklist of procedures for development of Series volumes is provided in the Appendix

Novel margin management to enhance Auchenorrhyncha biodiversity in intensive grasslands

Agricultural intensification, including changes in cutting, grazing and fertilizer regimes, has led to declines in UK and NW European grassland biodiversity. We aimed to develop field margin management practices that would support invertebrate diversity and abundance on intensively managed grassland farms, focusing on planthoppers and leafhoppers (Auchenorrhyncha). Replicated across four farms in south-west England, we manipulated conventional management practices (inorganic fertilizer, cutting frequency and height, and aftermath grazing) to create seven treatments along a gradient of decreasing management intensity and increasing sward architectural complexity. Auchenorrhyncha were sampled annually between 2003 and 2005. Auchenorrhyncha abundance and species richness was highest in the most extensively managed treatments. Abundance was lowest with frequent cutting, while species richness was lowest where cattle grazing occurred. Unexpectedly, application of inorganic fertilizer had no effect on Auchenorrhyncha abundance or species richness. Management options that enhance invertebrate diversity, while allowing the remainder of the field to be managed conventionally, represent a potentially important conservation tool for many lowland improved grasslands. Extensification of conventional management in field margin areas of such grasslands are likely to benefit this numerically dominant component of grassland invertebrate fauna. These management practices have the potential to be incorporated into existing UK and European agri-environment schemes

Non trivial generalizations of the Schwinger pair production result

We present new, non trivial generalizations of the recent Tomaras, Tsamis and Woodard extension of the original Schwinger formula for charged pair production in a constant field.Comment: 11 page

A conditional Smg6 mutant mouse model reveals circadian clock regulation through the nonsense-mediated mRNA decay pathway.

Nonsense-mediated messenger RNA (mRNA) decay (NMD) has been intensively studied as a surveillance pathway that degrades erroneous transcripts arising from mutations or RNA processing errors. While additional roles in physiological control of mRNA stability have emerged, possible functions in mammalian physiology in vivo remain unclear. Here, we created a conditional mouse allele that allows converting the NMD effector nuclease SMG6 from wild-type to nuclease domain-mutant protein. We find that NMD down-regulation affects the function of the circadian clock, a system known to require rapid mRNA turnover. Specifically, we uncover strong lengthening of free-running circadian periods for liver and fibroblast clocks and direct NMD regulation of Cry2 mRNA, encoding a key transcriptional repressor within the rhythm-generating feedback loop. Transcriptome-wide changes in daily mRNA accumulation patterns in the entrained liver, as well as an altered response to food entrainment, expand the known scope of NMD regulation in mammalian gene expression and physiology

A novel Smg6 mouse model reveals regulation of circadian period and daily CRY2 accumulation through the nonsense-mediated mRNA decay pathway

Nonsense-mediated mRNA decay (NMD) has been intensively studied as a surveillance pathway that degrades erroneous transcripts arising from mutations or RNA processing errors. While additional roles in controlling regular mRNA stability have emerged, possible functions in mammalian physiology in vivo have remained unclear. Here, we report a novel conditional mouse allele that allows converting the NMD effector nuclease SMG6 from wild-type to nuclease domain-mutant protein. We analyzed how NMD downregulation affects the function of the circadian clock, a system known to require rapid mRNA turnover. We uncover strong lengthening of free-running circadian periods for liver and fibroblast clocks, and direct NMD regulation of Cry2 mRNA, encoding a key transcriptional repressor within the rhythm-generating feedback loop. In the entrained livers of Smg6 mutant animals we reveal transcriptome-wide alterations in daily mRNA accumulation patterns, altogether expanding the known scope of NMD regulation in mammalian gene expression and physiology

Effective action for scalar fields and generalised zeta-function regularisation

Motivated by the study of quantum fields in a Friedman-Robertson-Walker (FRW) spacetime, the one-loop effective action for a scalar field defined in the ultrastatic manifold $R\times H^3/\Gamma$, $H^3/\Gamma$ being the finite volume, non-compact, hyperbolic spatial section, is investigated by a generalisation of zeta-function regularisation. It is shown that additional divergences may appear at one-loop level. The one-loop renormalisability of the model is discussed and making use of a generalisation of zeta-function regularisation, the one-loop renormalisation group equations are derived.Comment: Latex, 16 pages, no figures; Latex mistakes corrected; accepted for publication in Physical Review