549 research outputs found

    Fiscal shocks in an efficiency wage model

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    This paper illustrates a particular limited information strategy for assessing the empirical plausibility of alternative quantitative general equilibrium business cycle models. The basic strategy is to test whether a model economy can account for the response of actual economy to an exogenous shock. Here we concentrate on the response of aggregate hours worked and real wages to a fiscal policy shock. The fiscal policy shock is identified with the dynamic response of government purchases and averages marginal income tax rates to an exogenous increase in military purchases. Burnside, Eichenbaum and Fisher (1999) show that standard Real business Cycle models cannot account for the salient features of how hours worked and after - tax real wages respond to a fiscal policy shock. In this paper we show that this failure extends to a class of business cycle models in which the labor is characterized by efficiency wages.Fiscal policy ; Wages

    In situ mixing of organic matter decreases hydraulic conductivity of denitrification walls in sand aquifers

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    In a previous study, a denitrification wall was constructed in a sand aquifer using sawdust as the carbon substrate. Ground water bypassed around this sawdust wall due to reduced hydraulic conductivity. We investigated potential reasons for this by testing two new walls and conducting laboratory studies. The first wall was constructed by mixing aquifer material in situ without substrate addition to investigate the effects of the construction technique (mixed wall). A second, biochip wall, was constructed using coarse wood chips to determine the effect of size of the particles in the amendment on hydraulic conductivity. The aquifer hydraulic conductivity was 35.4 m/d, while in the mixed wall it was 2.8 m/d and in the biochip wall 3.4 m/d. This indicated that the mixing of the aquifer sands below the water table allowed the particles to re-sort themselves into a matrix with a significantly lower hydraulic conductivity than the process that originally formed the aquifer. The addition of a coarser substrate in the biochip wall significantly increased total porosity and decreased bulk density, but hydraulic conductivity remained low compared to the aquifer. Laboratory cores of aquifer sand mixed under dry and wet conditions mimicked the reduction in hydraulic conductivity observed in the field within the mixed wall. The addition of sawdust to the laboratory cores resulted in a significantly higher hydraulic conductivity when mixed dry compared to cores mixed wet. This reduction in the hydraulic conductivity of the sand/sawdust cores mixed under saturated conditions repeated what occurred in the field in the original sawdust wall. This indicated that laboratory investigations can be a useful tool to highlight potential reductions in field hydraulic conductivities that may occur when differing materials are mixed under field conditions

    Fiscal Shocks in an Efficiency Wage Model

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    This paper analyzes the ability of a general equilibrium efficiency wage model to account for the estimated response of hours worked and of real wages to a fiscal policy shock. Our key finding is that the model cannot do so unless we make the counterfactual assumption that marginal tax rates are constant. The model shares the strengths and weaknesses of high labor supply elasticity Real Business Cycle models. In particular it can account for the conditional volatility of real wages and hours worked. But it cannot account for the temporal pattern of how these variables respond to a fiscal policy shock and generates a counterfactual negative conditional correlation between government purchases and hours worked.

    Exploring How Well UK Coach Education Meets the Needs of Women Sports Coaches

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    Inclusive and equitable processes are important to the development of sports coaching. The aim of this study was to explore how well UK coach education meets the needs of women sports coaches in order to make recommendations to further enhance the engagement of, and support for, aspiring and existing women coaches. The national governing bodies (NGBs) of four sports (Cycling, Equestrian, Gymnastics and Rowing) volunteered to participate and semi-structured interviews using the tenants of Appreciative Inquiry (AI) within a Self Determination Theory (SDT) framework were undertaken with 23 coaches, eight coach educators and five NGB officers. The data themed into an analytic structure derived from SDT comprising ‘Autonomy: Freedom to coach’, ‘Coaching competence’, and ‘Relatedness and belonging’. The coaches perceived potential benefit from enhanced relatedness and belonging within their sport with the findings suggesting that NGBs should embrace coach-led decision making in terms of the developmental topics which are important and should adopt the development of competence, rather than assessing technical understanding, as the foundational principle of more inclusive coach education. Future research should investigate the impact of the inclusive practices which are recommended within this investigation such as the softening of the technocratic focus of formal coach education

    Hsp70 in mitochondrial biogenesis

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    The family of hsp70 (70 kilodalton heat shock protein) molecular chaperones plays an essential and diverse role in cellular physiology, Hsp70 proteins appear to elicit their effects by interacting with polypeptides that present domains which exhibit non-native conformations at distinct stages during their life in the cell. In this paper we review work pertaining to the functions of hsp70 proteins in chaperoning mitochondrial protein biogenesis. Hsp70 proteins function in protein synthesis, protein translocation across mitochondrial membranes, protein folding and finally the delivery of misfolded proteins to proteolytic enzymes in the mitochondrial matrix

    Large time wellposdness to the 3-D Capillary-Gravity Waves in the long wave regime

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    In the regime of weakly transverse long waves, given long-wave initial data, we prove that the nondimensionalized water wave system in an infinite strip under influence of gravity and surface tension on the upper free interface has a unique solution on [0,{T}/\eps] for some \eps independent of constant T.T. We shall prove in the subsequent paper \cite{MZZ2} that on the same time interval, these solutions can be accurately approximated by sums of solutions of two decoupled Kadomtsev-Petviashvili (KP) equations.Comment: Split the original paper(The long wave approximation to the 3-D capillary-gravity waves) into two parts, this is the first on

    Goldstino and sgoldstino in microscopic models and the constrained superfields formalism

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    We examine the exact relation between the superconformal symmetry breaking chiral superfield (X) and the goldstino superfield in microscopic models of an arbitrary Kahler potential (K) and in the presence of matter fields. We investigate the decoupling of the massive sgoldstino and scalar matter fields and the offshell/onshell-SUSY expressions of their superfields in terms of the fermions composites. For general K of two superfields, we study the properties of the superfield X after integrating out these scalar fields, to show that in the infrared it satisfies (offshell) the condition X3=0X^3=0 and X20X^2\not=0. We then compare our results to those of the well-known method of constrained superfields discussed in the literature, based on the conjecture X2=0X^2=0. Our results can be used in applications, to couple offshell the (s)goldstino fields to realistic models such as the MSSM.Comment: 24 page

    Investigation of growth responses in saprophytic fungi to charred biomass

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    We present the results of a study testing the response of two saprophytic white-rot fungi species, Pleurotus pulmonarius and Coriolus versicolor, to charred biomass (charcoal) as a growth substrate. We used a combination of optical microscopy, scanning electron microscopy, elemental abundance measurements, and isotope ratio mass spectrometry (<sup>13</sup>C and <sup>15</sup>N) to investigate fungal colonisation of control and incubated samples of Scots Pine (Pinus sylvestris) wood, and charcoal from the same species produced at 300 °C and 400 °C. Both species of fungi colonise the surface and interior of wood and charcoals over time periods of less than 70 days; however, distinctly different growth forms are evident between the exterior and interior of the charcoal substrate, with hyphal penetration concentrated along lines of structural weakness. Although the fungi were able to degrade and metabolise the pine wood, charcoal does not form a readily available source of fungal nutrients at least for these species under the conditions used in this study

    On non-universal Goldstino couplings to matter

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    Using the constrained superfields formalism to describe the interactions of a light goldstino to matter fields in supersymmetric models, we identify generalised, higher-order holomorphic superfield constraints that project out the superpartners and capture the non-universal couplings of the goldstino to matter fields. These arise from microscopic theories in which heavy superpartners masses are of the order of the supersymmetry breaking scale (\sqrt f). In the decoupling limit of infinite superpartners masses, these constraints reduce to the familiar, lower-order universal constraints discussed recently, that describe the universal goldstino-matter fields couplings, suppressed by inverse powers of \sqrt f. We initiate the study of the couplings of the Standard Model (SM) fields to goldstino in the constrained superfields formalism.Comment: 28 pages; one comment adde

    Structural and dielectric properties of Sr2_{2}TiO4_{4} from first principles

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    We have investigated the structural and dielectric properties of Sr2_{2}TiO4_{4},the first member of the Srn+1_{n+1}Tin_{n}O3n+1_{3n+1} Ruddlesden-Popper series, within density functional theory. Motivated by recent work in which thin films of Sr2_{2}TiO4_{4} were grown by molecular beam epitaxy (MBE) on SrTiO3_{3} substrates, the in-plane lattice parameter was fixed to the theoretically optimized lattice constant of cubic SrTiO3_{3} (n=\infty), while the out-of-plane lattice parameter and the internal structural parameters were relaxed. The fully relaxed structure was also investigated. Density functional perturbation theory was used to calculate the zone-center phonon frequencies, Born effective charges, and the electronic dielectric permittivity tensor. A detailed study of the contribution of individual infrared-active modes to the static dielectric permittivity tensor was performed. The calculated Raman and infrared phonon frequencies were found to be in agreement with experiment where available. Comparisons of the calculated static dielectric permittivity with experiments on both ceramic powders and epitaxial thin films are discussed.Comment: 11 pages, 1 figure, 8 tables, submitted to Phys. Rev.
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