4,217 research outputs found
Chromosomes of the bowhead whale (Balaena mysticetus linnaeus)
Thesis (M.S.) University of Alaska Fairbanks, 1979The somatic chromosomes of the bowhead whale, Balaena mysticetus, are described for the first time using homogeneous staining and trypsin G-banding. The diploid chromosome number in all cells studied is 42. The bowhead karyotype retains many features of the general 2n = 44 cetacean karyotype from which it is derived, yet it is the first mysticete for which a chromosome number other than 2n = 44 has been reported. The advanced karyotype of the bowhead may reflect greater anatomical specialization of this whale than of other mysticetes. Cytogenetic data for cetaceans are reviewed within the framework of a model of speciation in sympatry
Absence of a Slater Transition in The Two-Dimensional Hubbard Model
We present well-controlled results on the metal to insulator transition (MIT)
within the paramagnetic solution of the dynamical cluster approximation (DCA)
in the two-dimensional Hubbard model at half-filling. In the strong coupling
regime, a local picture describes the properties of the model; there is a large
charge gap . In the weak-coupling regime, we find a symbiosis
of short-range antiferromagnetic correlations and moment formation cause a gap
to open at finite temperature as in one dimension. Hence, this excludes the
mechanism of the MIT proposed by Slater long ago.Comment: 4 pages, 5 figure
Bond excitations in the pseudogap phase of the Hubbard Model
Using the dynamical cluster approximation, we calculate the correlation
functions associated with the nearest neighbor bond operator which measure the
z component of the spin exchange in the two-dimensional Hubbard model with
equal to the bandwidth. We find that in the pseudogap region, the local bond
susceptibility diverges at T=0. This shows the existence of degenerate bond
spin excitation and implies quantum criticality and bond order formation when
long range correlations are considered. The strong correlation between
excitations on parallel neighboring bonds suggests bond singlet dimerization.
The suppression of divergence for implies that tor these
model parameters this is quantum critical point which separates the
unconventional pseudogap region characterized by bond order from a conventional
Fermi liquid.Comment: 5 pages, 5 figure
A Maximum Entropy Method of Obtaining Thermodynamic Properties from Quantum Monte Carlo Simulations
We describe a novel method to obtain thermodynamic properties of quantum
systems using Baysian Inference -- Maximum Entropy techniques. The method is
applicable to energy values sampled at a discrete set of temperatures from
Quantum Monte Carlo Simulations. The internal energy and the specific heat of
the system are easily obtained as are errorbars on these quantities. The
entropy and the free energy are also obtainable. No assumptions as to the
specific functional form of the energy are made. The use of a priori
information, such as a sum rule on the entropy, is built into the method. As a
non-trivial example of the method, we obtain the specific heat of the
three-dimensional Periodic Anderson Model.Comment: 8 pages, 3 figure
A novel FLEX supplemented QMC approach to the Hubbard model
This paper introduces a novel ansatz-based technique for solution of the
Hubbard model over two length scales. Short range correlations are treated
exactly using a dynamical cluster approximation QMC simulation, while
longer-length-scale physics requiring larger cluster sizes is incorporated
through the introduction of the fluctuation exchange (FLEX) approximation. The
properties of the resulting hybrid scheme are examined, and the description of
local moment formation is compared to exact results in 1D. The effects of
electron-electron coupling and electron doping on the shape of the
Fermi-surface are demonstrated in 2D. Causality is examined in both 1D and 2D.
We find that the scheme is successful if QMC clusters of are used
(with sufficiently high temperatures in 1D), however very small QMC clusters of
lead to acausal results
Financial innovation and corporate mergers
Consolidation and merger of corporations
Combined air and water pollution control system
A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system
- …