6,314 research outputs found

    The Camp View of Inflation Forecasts

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    Analyzing sample moments of survey forecasts, we derive disagreement and un- certainty measures for the short- and medium term inflation outlook. The latter provide insights into the development of inflation forecast uncertainty in the context of a changing macroeconomic environment since the beginning of 2008. Motivated by the debate on the role of monetary aggregates and cyclical variables describing a Phillips-curve logic, we develop a macroeconomic indicator spread which is assumed to drive forecasters’ judgments. Empirical evidence suggests procyclical dynamics between disagreement among forecasters, individual forecast uncertainty and the macro-spread. We call this approach the camp view of inflation forecasts and show that camps form up whenever the spread widens.monetary policy, survey forecasts, inflation uncertainty, heterogenous beliefs and expectations, monetary aggregates

    Effects of ursodeoxycholic acid on synthesis of cholesterol and bile acids in healthy subjects

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    Background/Aims: Ursodeoxycholic acid ( UDCA) decreases biliary secretion of cholesterol and is therefore used for the dissolution of cholesterol gallstones. It remains unclear whether these changes in biliary cholesterol excretion are associated with changes in cholesterol synthesis and bile acid synthesis. We therefore studied the activities of rate-limiting enzymes of cholesterol synthesis and bile acid synthesis, 3-hydroxy-3-methyl-glutarylcoenzyme A reductase and cholesterol 7alpha-hydroxylase, respectively, in normal subjects during UDCA feeding. Methods: UDCA was given to 8 healthy volunteers ( 5 men, 3 women; age 24-44 years) in a single dose of 10-15 mg/kg body weight for 40 days. Before and during ( days 3, 5, 10, 20, 30 and 40) UDCA treatment, urinary excretion of mevalonic acid and serum concentrations of 7alpha-hydroxy-4-cholesten-3-one (7alpha-HCO) were determined as markers of cholesterol and bile acid synthesis, respectively. The Wilcoxon signed rank test and Spearman's rank correlation coefficient were used for statistical analysis. Results: Cholesterol synthesis and serum lipid concentrations remained unchanged during UDCA treatment for 40 days. However, synthesis of bile acids increased during long-term treatment with UDCA as reflected by an increase in 7alpha-HCO serum concentrations from 39.7 +/- 21.3 ng/ml (median 32.8 ng/ml) before treatment to 64.0 +/- 30.4 ng/ml (median 77.5 ng/ml) at days 30-40 of UDCA treatment ( p < 0.05). Conclusions: UDCA treatment does not affect cholesterol synthesis in the liver, but does increase bile acid synthesis after prolonged treatment. This may represent a compensatory change following decreased absorption of endogenous bile acids as observed with UDCA therapy

    Meson production in two-photon interactions at energies available at CERN Large Hadron Collider

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    The meson production cross sections are estimated considering photon-photon interactions in hadron - hadron collisions at CERN LHC energies. We consider a large number of mesons with photon-photon partial decay width well constrained by the experiment and some mesons which are currently considered as hadronic molecule and glueball candidates. Our results demonstrate that the experimental analysis of these states is feasible at CERN - LHC.Comment: 5 pages, 1 figure, 4 tables. Version published in Physical Review

    A comparison of atmospheric transport models for traffic emissions

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    De in Nederland gebruikte rekenmodellen voor luchtkwaliteit langs snelwegen en stadswegen geven wisselende resultaten. Voor berekening van jaargemiddelde concentraties van stikstofdioxide en fijn stof zijn de verschillen tussen modellen beperkt. Bij de berekening van meer specifieke aspecten van luchtkwaliteit, bijvoorbeeld het aantal overschrijdingsdagen, kunnen de verschillen tussen modelresultaten aanzienlijk groter zijn. Atmosferische verspreidingsmodellen berekenen luchtkwaliteit als gevolg van emissies door het verkeer. In Nederland is een aantal van deze verspreidingsmodellen in gebruik bij overwegend commerciele bureaus. Zij voeren berekeningen uit in opdracht van overheid en bedrijfsleven. De rekenmodellen die deze bureaus gebruiken werken volgens uiteenlopende rekenmethoden. Om vast te stellen in hoeverre de resultaten van de verschillende modellen met elkaar overeenstemmen, zijn in dit onderzoek zes in Nederland gebruikte rekenmodellen met elkaar vergeleken. Bij de berekening van de jaargemiddelde concentratie van stikstofdioxide en fijn stof langs snel- en stadswegen, liggen de resultaten van de modellen binnen een marge van 10-15% rond het gemiddelde van de modellen. Bij de berekening van het aantal overschrijdingsdagen voor fijn stof langs snelwegen liggen de verschillende modelresultaten echter in een bandbreedte van 30% rond het gemiddelde. Voor een typische stadswegsituatie is die bandbreedte 50%.This report presents the results of an intercomparison study of six atmospheric transport models for traffic situations in the Netherlands. A number of test cases were defined in consultation with the model owners in which the input parameters to the models, such as emissions, meteorological conditions and road characteristics. Two base cases were defined: one for roadways and one for urban roads, along with a number of variants on these two base cases. The variants, for example, consisted of different meteorological conditions, different background concentrations and the presence of a noise barrier. The model owners calculated - for both base cases and variants - the annual concentration of NO2 and PM10 and the number of days in which the daily threshold of 50 ug/m3 of PM10 is exceeded. For the roadway test cases annual levels of NO2 and PM10 calculated by the different models are within about 10% of the average of all model results. The large difference found in the number of exceedence days was caused by the difference in the methods used to derive the exceedence days. When using one standard method, as in the Dutch regulations, this difference fell to within 30%. Because of technical reasons only the "street canyon" variant was considered for urban roads. In this variant the model results were between 10% and 15% for NO2 and PM10, respectively, of the average of all models. If the contribution of the road alone is considered (i.e. comparing the concentrations without the prescribed background concentration), the models differ by a factor of 2 to 3 and the number of exceedence days for PM10 by a factor of 2.VROM-DG

    Coulomb Corrections for Coherent Electroproduction of Vector Mesons: Eikonal Approximation

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    Virtual radiative corrections due to the long range Coulomb forces of heavy nuclei with charge Z may lead to sizeable corrections to the Born cross section usually used for lepton-nucleus scattering processes. An introduction and presentation of the most important issues of the eikonal approximation is given. We present calculations for forward electroproduction production of rho mesons in a framework suggested by the VDM (vector dominance model), using the eikonal approximation. It turns out that Coulomb corrections may become relatively large. Some minor errors in the literature are corrected.Comment: 14 pages, 6 figures, published versio

    Non-verbal expressions of emotion - acoustics, valence, and cross cultural factors

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    This presentation will address aspects of the expression of emotion in non-verbal vocal behaviour, specifically attempting to determine the roles of both positive and negative emotions, their acoustic bases, and the extent to which these are recognized in non-Western cultures

    Bridging the gap between geometric and algebraic multi-grid methods

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    In this paper, a multi-grid solver for the discretisation of partial differential equations on complicated domains is developed. The algorithm requires as input the given discretisation only instead of a hierarchy of discretisations on coarser grids. Such auxiliary grids and discretisations are generated in a black-box fashion and are employed to define purely algebraic intergrid transfer operators. The geometric interpretation of the algorithm allows one to use the framework of geometric multigrid methods to prove its convergence. The focus of this paper is on the formulation of the algorithm and the demonstration of its efficiency by numerical experiments, while the analysis is carried out for some model problems

    Radion production in exclusive processes at CERN LHC

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    In the Randall-Sundrum (RS) scenario the compactification radius of the extra dimension is stabilized by the radion, which is a scalar field lighter than the graviton Kaluza-Klein states. It implies that the detection of the radion will be the first signature of the stabilized RS model. In this paper we study the exclusive production of the radion in electromagnetic and diffractive hadron - hadron collisions at the LHC. Our results demonstrate that the diffractive production of radion is dominant and should be feasible of study at CERN LHC.Comment: 6 pages, 3 figures, 1 tabl

    Raman cooling and heating of two trapped Ba+ ions

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    We study cooling of the collective vibrational motion of two 138Ba+ ions confined in an electrodynamic trap and irradiated with laser light close to the resonances S_1/2-P_1/2 (493 nm) and P_1/2-D_3/2 (650 nm). The motional state of the ions is monitored by a spatially resolving photo multiplier. Depending on detuning and intensity of the cooling lasers, macroscopically different motional states corresponding to different ion temperatures are observed. We also derive the ions' temperature from detailed analytical calculations of laser cooling taking into account the Zeeman structure of the energy levels involved. The observed motional states perfectly match the calculated temperatures. Significant heating is observed in the vicinity of the dark resonances of the Zeeman-split S_1/2-D_3/2 Raman transitions. Here two-photon processes dominate the interaction between lasers and ions. Parameter regimes of laser light are identified that imply most efficient laser cooling.Comment: 8 pages, 5 figure
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