2,774 research outputs found
A dichotomy in dust-jet orientation in radio galaxies
We have analyzed the position angle (PA) differences between radio jets and
dust distributions in the centers of Fanaroff & Riley Type 1 (FRI) radio
galaxies. We model the observed PA differences to infer the three-dimensional
relative orientation of jet and dust. Our main conclusion is that there is a
dichotomy in dust-jet-galaxy orientation both in projection and in
three-dimensional space. The orientation dichotomy can explain the
contradictory results obtained in previous studies. We briefly mention
scenarios that might explain the dichotomy.Comment: 2 pages, 2 figures, to appear in "The Interplay among Black Holes,
Stars and ISM in Galactic Nuclei", IAU Symposium 222, eds. Th. Storchi
Bergmann, L.C. Ho & H.R. Schmit
Clearing price distributions in call auctions
We propose a model for price formation in financial markets based on clearing
of a standard call auction with random orders, and verify its validity for
prediction of the daily closing price distribution statistically. The model
considers random buy and sell orders, placed following demand- and supply-side
valuation distributions; an equilibrium equation then leads to a distribution
for clearing price and transacted volume. Bid and ask volumes are left as free
parameters, permitting possibly heavy-tailed or very skewed order flow
conditions. In highly liquid auctions, the clearing price distribution
converges to an asymptotically normal central limit, with mean and variance in
terms of supply/demand-valuation distributions and order flow imbalance. By
means of simulations, we illustrate the influence of variations in order flow
and valuation distributions on price/volume, noting a distinction between high-
and low-volume auction price variance. To verify the validity of the model
statistically, we predict a year's worth of daily closing price distributions
for 5 constituents of the Eurostoxx 50 index; Kolmogorov-Smirnov statistics and
QQ-plots demonstrate with ample statistical significance that the model
predicts closing price distributions accurately, and compares favourably with
alternative methods of prediction
Superconformal hypermultiplets
We present theories of N=2 hypermultiplets in four spacetime dimensions that are invariant under rigid or local superconformal symmetries. The target spaces of theories with rigid superconformal invariance are (4n)-dimensional {\it special} hyper-K\"ahler manifolds. Such manifolds can be described as cones over tri-Sasakian metrics and are locally the product of a flat four-dimensional space and a quaternionic manifold. The latter manifolds appear in the coupling of hypermultiplets to N=2 supergravity. We employ local sections of an Sp bundle in the formulation of the Lagrangian and transformation rules, thus allowing for arbitrary coordinatizations of the hyper-K\"ahler and quaternionic manifolds
Verslechtering ruilvoet leidt tot lager inkomen agrarische sector
Sterke prijsstijgingen van een aantal belangrijke kostenfactoren hebben samen met lagere prijzen in de plantaardige sector geleid tot een verslechtering van de ruilvoet binnen de totale agrarische sector. De toename van de productiewaarde blijft ver achter bij die van de productiekosten. Toegevoegde waarde en inkomen dalen sterk
Facilities and their effect on face-to-face social contacts:research on the importance of social and commercial facilities which affect face-to-face social contacts in the anticipating area of Noord-Limburg
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