15,588 research outputs found
The Norman Site Excavations Near Wagoner, Oklahoma
The Norman site is seven miles southeast of Wagoner, Wagoner County, Okla., on State Highway 51. It is on the upper terraces on the west side of Grand River just north of the approach to the new bridge. Principal mound is a double unit; the larger mound, clearly visible from the highway, is conical, 27\u27 high and 90\u27 in diameter; the low mound, on the north, is circular, 7\u27 high and 100\u27 in diameter; a low, broad saddle 12\u27 long connects the 2 mounds. An extensive habitation area, Unit IV, extends to the north and northeast of Mound I-2. Unit II was also a double unit; the larger mound was originally conical, 70\u27 in diameter and probably 10\u27 high. It was only 6.5\u27 high when excavated, owing to a large pit previously dug from the apex. The smaller mound, on the north, was circular, 2.5\u27 high and 45\u27 in diameter. The edges of the two mounds overlapped somewhat. Unit III is a low circular mound 7\u27 high and 11 O\u27 in diameter. Unit VI is a low, circular mound 1.5\u27 high and 45\u27 in diameter. Unit II was completely excavated; approximately one third of Unit II, a portion of Mound 1-2 and a portion of the habitation area were also excavated
SPH simulations of turbulence in fixed and rotating boxes in two dimensions with no-slip boundaries
In this paper we study decaying turbulence in fixed and rotating boxes in two
dimen- sions using the particle method SPH. The boundaries are specified by
boundary force particles, and the turbulence is initiated by a set of gaussian
vortices. In the case of fixed boxes we recover the results of Clercx and his
colleagues obtained using both a high accuracy spectral method and experiments.
Our results for fixed boxes are also in close agreement with those of Monaghan1
and Robinson and Monaghan2 obtained using SPH. A feature of decaying turbulence
in no-slip, square, fixed boundaries is that the angular momentum of the fluid
varies with time because of the reaction on the fluid of the viscous stresses
on the boundary. We find that when the box is allowed to rotate freely, so that
the total angular momentum of box and fluid is constant, the change in the
angular momentum of the fluid is a factor ~ 500 smaller than is the case for
the fixed box, and the final vorticity distribution is different. We also
simulate the behaviour of the turbulence when the box is forced to rotate with
small and large Rossby number, and the turbulence is initiated by gaussian
vortices as before. If the rotation of the box is maintained after the
turbulence is initiated we find that in the rotating frame the decay of kinetic
energy, enstrophy and the vortex structure is insensitive to the angular
velocity of the box. On the other hand, If the box is allowed to rotate freely
after the turbulence is initiated, the evolved vortex structure is completely
different
Bergman spaces of natural G-manifolds
Let G be a unimodular Lie group, X a compact manifold with boundary, and M
the total space of a principal bundle G--> M-->X so that M is also a strongly
pseudoconvex complex manifold. In this work, we show that if there exists a
point p in bM such that T_p(G) is contained in the complex tangent space of bM
at p, then the Bergman space of M is large. Natural examples include the gauged
G-complexifications of Heinzner, Huckleberry, and Kutzschebauch.Comment: 24 pages, no figure
Endogenous Mode of Competition in General Equilibrium
This paper endogenises the extent of intra-sectoral competition in a multi-sectoral model of oligopoly in general equilibrium. Firms choose capacity followed by prices. If the benefits of capacity investment in a given sector are below a threshold level, the sector exhibits Bertrand behaviour, otherwise it exhibits Cournot behaviour. By endogenising the threshold parameter in general equilibrium, we show how exogenous shocks alter the mix of sectors between "more" and "less" competitive, or Bertrand and Cournot. The model also has implications for the effects of trade liberalisation and technological change on the relative wages of skilled and unskilled workers.Bertrand and Cournot competition; GOLE (General Oligopolistic Equilibrium); Kreps- Scheinkman; market integration
First record of Xenopsylla gratiosa Jordan & Rothschild, 1923 from the Maltese Islands (Siphonaptera: Pulicidae)
Xenopsylla gratiosa is reported for the first time from the Maltese Islands. The species was found in an abandoned nest of a Cory’s Shearwater, Calonectris diomedea on the island of Filfla. Brief notes are included on previous records of fleas from the Maltese Islands and taxonomic, distributional and ecological notes are provided for Xenopsylla gratiosapeer-reviewe
Toward Spin Squeezing with Trapped Ions
Building robust instruments capable of making interferometric measurements
with precision beyond the standard quantum limit remains an important goal in
many metrology laboratories. We describe here the basic concepts underlying
spin squeezing experiments that allow one to surpass this limit. In priniciple
it is possible to reach the so-called Heisenberg limit, which constitutes an
improvement in precision by a factor , where is the number of
particles on which the measurement is carried out. In particular, we focus on
recent progress toward implementing spin squeezing with a cloud of beryllium
ions in a Penning ion trap, via the geometric phase gate used more commonly for
performing two-qubit entangling operations in quantum computing experiments.Comment: 18 pages, 9 figures, Contribution to Quantum Africa 2010 conference
proceeding
- …