124,346 research outputs found

    Supply, demand and monetary policy shocks in a multi-country new Keynesian model

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    This paper estimates and solves a multi-country version of the standard DSGE New Keynesian (NK) model. The country-specific models include a Phillips curve determining inflation, an IS curve determining output, a Taylor Rule determining interest rates, and a real effective exchange rate equation. The IS equation includes a real exchange rate variable and a countryspecific foreign output variable to capture direct inter-country linkages. In accord with the theory all variables are measured as deviations from their steady states, which are estimated as long-horizon forecasts from a reduced-form cointegrating global vector autoregression. The resulting rational expectations model is then estimated for 33 countries on data for 1980Q1-2006Q4, by inequality constrained IV, using lagged and contemporaneous foreign variables as instruments, subject to the restrictions implied by the NK theory. The multi-country DSGE NK model is then solved to provide estimates of identified supply, demand and monetary policy shocks. Following the literature, we assume that the within country supply, demand and monetary policy shocks are orthogonal, though shocks of the same type (e.g. supply shocks in different countries) can be correlated. We discuss estimation of impulse response functions and variance decompositions in such large systems, and present estimates allowing for both direct channels of international transmission through regression coefficients and indirect channels through error spillover effects. Bootstrapped error bands are also provided for the cross country responses of a shock to the US monetary policy

    A note on fragmentability and weak-G_delta sets

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    In terms of fragmentability, we describe a new class of Banach spaces which do not contain weak-G_delta open bounded subsets. In particular, none of these spaces is isomorphic to a separable polyhedral space

    Responses of a bacterial pathogen to phosphorus limitation of its aquatic invertebrate host

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    Host nutrition is thought to affect the establishment, persistence, and severity of pathogenic infections. Nutrient-deficient foods possibly benefit pathogens by constraining host immune function or benefit hosts by limiting parasite growth and reproduction. However, the effects of poor elemental food quality on a host's susceptibility to infection and disease have received little study. Here we show that the bacterial microparasite Pasteuria ramosa is affected by the elemental nutrition of its aquatic invertebrate host, Daphnia magna. We found that high food carbon : phosphorus (C: P) ratios significantly reduced infection rates of Pasteuria in Daphnia and led to lower within-host pathogen multiplication. In addition, greater virulent effects of bacterial infection on host reproduction were found in Daphnia-consuming P-deficient food. Poor Daphnia elemental nutrition thus reduced the growth and reproduction of its bacterial parasite, Pasteuria. The effects of poor host nutrition on the pathogen were further evidenced by Pasteuria's greater inhibition of reproduction in P-limited Daphnia. Our results provide strong evidence that elemental food quality can significantly influence the incidence and intensity of infectious disease in invertebrate hosts

    Are violent events responsible of a Galaxy Morphological loop?

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    We use cosmological SPH simulations to investigate the effects of mergers and interactions on the formation of the bulge and disc components of galactic systems. We find that secular evolution during mergers seems to be a key process in the formation of stable disc-bulge systems with observational counterparts and contributes to establish the fundamental relations observed in galaxies. Our findings suggest that the secular evolution phase couples the formation mechanisms of the bulge and disc components. According to our results, depending on the particular stability properties and merger parameters, violents events could drive a morphological loop in which the outcome could be a disc or a spheroid.Comment: 2 pages. To appear in the proceedings of the IAUC198 "Near-Field Cosmology with Dwarf Elliptical Galaxies", 14 - 18 March 2005, Les Diablerets, Switzerlan

    Solar flux and its variations

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    Data are presented on the solar irradiance as derived from a number of sources. An attempt was made to bring these data onto a uniform scale. Summation of fluxes at all wavelengths yields a figure of 1357.826 for the solar constant. Estimates are made of the solar flux variations due to flares, active regions (slowly varying component), 27-day period, and the 11-yr cycle. Solar activity does not produce a significant variation in the value of the solar constant. Variations in the X-ray and EUV portions of the solar flux may be several orders of magnitude during solar activity, especially at times of major flares. It is established that these short wavelength flux enhancements cause significant changes in the terrestrial ionosphere

    Prospect for relic neutrino searches

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    Unlike the relic photons, relic neutrinos have not so far been observed. The Cosmic Neutrino Background (Cν\nuB) is the oldest relic from the Big Bang, produced a few seconds after the Bang itself. Due to their impact in cosmology, relic neutrinos may be revealed indireclty in the near future through cosmological observations. In this talk we concentrate on other proposals, made in the last 30 years, to try to detect the Cν\nuB directly, either in laboratory searches (through tiny accelerations they produce on macroscopic targets) or through astrophysical observations (looking for absorption dips in the flux of Ultra-High Energy neutrinos, due to the annihilation of these neutrinos with relic neutrinos at the Z-resonance). We concentrate mainly on the first of these two possibilities.Comment: Talk given at the Nobel Symposium on Neutrino Physics, Enkoping, Sweden, Augus 19-24, 2004; 16 page

    A novel synthetic chemistry approach to linkage-specific ubiquitin conjugation.

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    Ubiquitination is of great importance as the post-translational modification of proteins with ubiquitin, or ubiquitin chains, facilitates a number of vital cellular processes. Herein we present a facile method of preparing various ubiquitin conjugates under mild conditions using michael acceptors based on dibromo-maleimides and dibromo-pyridazinediones

    Stuffed MO layer as a diffusion barrier in metallizations for high temperature electronics

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    Auger electron spectroscopy was employed to characterize the diffusion barrier properties of molybdenum in the CrSi2/Mo/Au metallization system. The barrier action of Mo was demonstrated to persist even after 2000 hours annealing time at 300 C in a nitrogen ambient. At 340 C annealing temperature, however, rapid interdiffusion was observed to have occurred between the various metal layers after only 261 hours. The presence of controlled amounts of oxygen in the Mo layer is believed to be responsible for suppressing the short circuit interdiffusion between the thin film layers. Above 340 C, its is believed that the increase in the oxygen mobility led to deterioration of its stuffing action, resulting in the rapid interdiffusion of the thin film layers along grain boundaries

    Utilization of ERTS-1 data to monitor and classify eutrophication of inland lakes

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    A technique is being developed for use of ERTS in estimating and monitoring trophic levels of inland lakes. Preliminary findings are that Michigan lakes and ponds of one acre or more are resolvable in bands 5, 6 and 7 of NASA MSS imagery under fair conditions (haze and 70% cloud cover). In processed imagery (CCT) smaller features, including water color patterns, are evident within some lakes of 40 acres or more. Image distortion of lake size, shape, orientation, etc. is minimal; discrimination of lakes and ponds from various wetlands is good. Subsequent ERTS and aircraft imagery will be correlated with detailed ground truth of water color and quality in eutrophic test lakes
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