12,167 research outputs found

    The role of investment, fundamental Q and financing frictions in agricultural investment decisions: an analysis pre and post financial crisis

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    JEL classifcation: G31, G32, F34This paper uses a fundamental Q model of investment to consider the role played by nancing frictions in agricultural investment decisions, controlling econometrically for censoring, heterogeneity and errors-in-variables. Our ndings suggest that farmer's in- vestment decisions are not driven by market fundamentals. We nd some evidence that debt overhang restricts investment but investment is not dependent on liquidity or internal funds. The role of nancing frictions in determining investment decisions changes in the post- nancial crisis period when debt overhang becomes a signi cant impediment to farm investment. The evidence suggests that farmers increasingly rely on internal liquidity to drive investment. Finally, we nd no evidence that farmers use o -farm capital to fund on-farm investment.Teagasc Walsh Fellowship Programm

    Study of spectral moments in semileptonic decays of the b hadron with the DELPHI detector at LEP

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    The measurement of the moments of hadronic mass spectrum and of lepton energy spectrum based on a sample of semileptonic decays of the b hadron selected from Z0bbˉZ^0 \to b \bar b events recorded with the DELPHI detector at LEP, are presented. These results are interpreted in terms of constraints on the quark masses and on the b-quark kinetic energy value.Comment: Presented at the XXXI Conference on High Energy Physics Amsterdam, July 200

    A Calculus of Bounded Capacities

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    Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

    Role of heat generation and thermal diffusion during frontal photopolymerization

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    Frontal photopolymerization (FPP) is a rapid and versatile solidification process that can be used to fabricate complex three-dimensional structures by selectively exposing a photosensitive monomer-rich bath to light. A characteristic feature of FPP is the appearance of a sharp polymerization front that propagates into the bath as a planar traveling wave. In this paper, we introduce a theoretical model to determine how heat generation during photopolymerization influences the kinetics of wave propagation as well as the monomer-to-polymer conversion profile, both of which are relevant for FPP applications and experimentally measurable. When thermal diffusion is sufficiently fast relative to the rate of polymerization, the system evolves as if it were isothermal. However, when thermal diffusion is slow, a thermal wavefront develops and propagates at the same rate as the polymerization front. This leads to an accumulation of heat behind the polymerization front which can result in a significant sharpening of the conversion profile and acceleration of the growth of the solid. Our results also suggest that a novel way to tailor the dynamics of FPP is by imposing a temperature gradient along the growth directio

    The role of fundamental Q and financing frictions in agricultural investment decisions: an analysis pre and post financial crisis

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    This paper uses a fundamental Q model of investment to consider the role played by financing frictions in agricultural investment decisions, controlling econometrically for censoring, heterogeneity and errors-in-variables. Our findings suggest that farmer's investment decisions are not driven by market fundamentals. We find some evidence that debt overhang restricts investment but investment is not dependent on liquidity or internal funds. The role of financing frictions in determining investment decisions changes in the post-financial crisis period when debt overhang becomes a significant impediment to farm investment. The evidence suggests that farmers increasingly rely on internal liquidity to drive investment. Finally, we find no evidence that farmers use off-farm capital to fund on-farm investment.Credit Constraints, Firm Level Investment, Tobin's Q, Debt

    Effect of bow-type initial imperfection on the buckling load and mass of graphite-epoxy blade-stiffened panels

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    A structural synthesis computer code which accounts for first order effects of an initial bow and which can be used for sizing stiffened composite panels having an arbitrary cross section is used to study graphite blade-stiffened panels. The effect of a small initial bow on both the load carrying ability of panels and on the mass of panels designed to carry a specified load is examined. Large reductions in the buckling load caused by a small initial bow emphasize the need for considering a bow when a panel is designed

    Vibration and Instability of Plate-Assemblies including Shear and Anisotropy (VIPASA) user's guide, addendum

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    Extensions developed at Langley Research Center to the VIPASA computer program are described including a procedure for simple thermal stress analysis and options for graphical display of output. Input requirements for operation of the modified program are given in detail

    The role of financing frictions in agricultural investment decisions: an analysis pre and post financial crisis

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    This paper uses a fundamental Q model of investment to consider the role played by financing frictions in agricultural investment decisions, controlling econometrically for censoring, heterogeneity and errors-in-variables. Our findings suggest that farmer's investment decisions are not driven by market fundamentals. We find some evidence that debt overhang restricts investment but investment is not dependent on liquidity or internal funds. The role of financing frictions in determining investment decisions changes in the post-financial crisis period when debt overhang becomes a significant impediment to farm investment. The evidence suggests that farmers increasingly rely on internal liquidity to drive investment. Finally, we find no evidence that farmers use on-farm capital to fund on-farm investment.Credit Constraints, Firm Level Investment, Tobin's Q, Debt, Agricultural Finance, G31, G32, F34,

    Controlled topological transitions in thin film phase separation

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    In this paper the evolution of a binary mixture in a thin-film geometry with a wall at the top and bottom is considered. By bringing the mixture into its miscibility gap so that no spinodal decomposition occurs in the bulk, a slight energetic bias of the walls towards each one of the constituents ensures the nucleation of thin boundary layers that grow until the constituents have moved into one of the two layers. These layers are separated by an interfacial region where the composition changes rapidly. Conditions that ensure the separation into two layers with a thin interfacial region are investigated based on a phase-field model. Using matched asymptotic expansions a corresponding sharp-interface problem for the location of the interface is established. It is then argued that this newly created two-layer system is not at its energetic minimum but destabilizes into a controlled self-replicating pattern of trapezoidal vertical stripes by minimizing the interfacial energy between the phases while conserving their area. A quantitative analysis of this mechanism is carried out via a thin-film model for the free interfaces, which is derived asymptotically from the sharp-interface model.Comment: Submitted 23/12/201
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