28,659 research outputs found
Price-concentration analysis in merger cases with differentiated products
This paper considers the empirical assessment of the relationship between prices and number of firms in local markets in geographic or, more generally, characteristic space and its use as evidence in merger cases. It outlines a structural, semi-nonparametric econometric model of competition in such markets, examines its testable implications in terms of price-concentration relationships, and demonstrates that the model is non-parametrically identified. This general approach to price-concentration analysis in differentiated product markets is illustrated in a small-scale application to cinemas in the UK. The application highlights the main decision points faced by an authority when assessing the weight that can be attached to this type of analysis as evidence
12C emission from 114Ba and nuclear properties
We investigate the influence of nuclear masses, radii, and interaction potentials on 12C radioactivity of 114the best representative of a new island of cluster emitters leading to daughter nuclei around the doubly magic 100Sn. Three different models are considered: one derived by Blendowske, Fliessbach, and Walliser (BFW) from the many-body theory of alpha decay, as well as our analytical (ASAF) and numerical (NuSAF) superasymmetric fission models. A Q value larger by 1 MeV or an ASAF potential barrier reduced by 3% are producing a half-life shorter by 2 orders of magnitude. A similar effect can be obtained within BFW and NuSAF by a decrease of the action integral with less than 10% and 5%, respectively. By increasing the radius constant within ASAF or BFW models by 10%, the half-life becomes shorter by 3 orders of magnitude
Volatility Persistence in Commodity Futures:Inventory and Time-to-Delivery Effects
Most financial asset returns exhibit volatility persistence. We investigate this phenomenon in the context of daily returns in commodity futures markets. We show that the time gap between the arrival of news to the markets and the delivery time of futures contracts is the fundamental variable in explaining volatility persistence in the lumber futures market. We also find an inverse relationship between inventory levels and lumber futures volatility.volatility persistence, theory of storage, volatility, futures markets, lumber, Agricultural Finance,
Components of Grain Futures Price Volatility
We analyze the determinants of daily futures price volatility in corn, soybeans, wheat, and oats markets from 1986 to 2007. Combining the information from simultaneously traded contracts, a generalized least squares method is implemented that allows us to clearly distinguish among time-to-delivery effects, seasonality, calendar trend, and volatility persistence. We find strong evidence of time-to-delivery (Samuelson) effects and systematic seasonal components with volatility increasing prior to harvest timesĂąâŹâ an indirect confirmation of the theory of storage.futures markets, Samuelson effect, seasonality, time to maturity, volatility, Crop Production/Industries, Risk and Uncertainty,
Three-cluster nuclear molecules
A three-center phenomenological model able to explain, at least from a qualitative point of view, the difference in the observed yield of a particle-accompanied fission and that of binary fission was developed. It is derived from the liquid drop model under the assumption that the aligned configuration, with the emitted particle between the light and heavy fragment is obtained by increasing continuously the separation distance, while the radii of the light fragment and of the light particle are kept constant. During the first stage of the deformation one has a two-center evolution until the neck radius becomes equal to the radius of the emitted particle. Then the three center starts developing by decreasing with the same amount the two tip distances. In such a way a second minimum, typical for a cluster molecule, appears in the deformation energy. Examples are presented for Pu parent nucleus emitting -particles and C in a ternary process
Potential energy surfaces for cluster emitting nuclei
Potential energy surfaces are calculated by using the most advanced
asymmetric two-center shell model allowing to obtain shell and pairing
corrections which are added to the Yukawa-plus-exponential model deformation
energy. Shell effects are of crucial importance for experimental observation of
spontaneous disintegration by heavy ion emission. Results for 222Ra, 232U,
236Pu and 242Cm illustrate the main ideas and show for the first time for a
cluster emitter a potential barrier obtained by using the
macroscopic-microscopic method.Comment: 10 pages, 21 figures, revtex
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