34,658 research outputs found
Further New Records of Coleoptera and Other Insects from Wisconsin
Specimens of eleven different species of insects, representing seven separate families of Coleoptera, and one family each of Hemiptera, Lepidoptera, Diptera, and Hymenoptera, are herein reported as new to Wisconsin. These genera or species occur respectively within the following families: Leiodidae, Monotomidae, Cucujidae, Cryptophagidae, Ciidae, Tetratomidae, Curculionidae, Pentatomidae, Glyphipterigidae, Phoridae, and Pteromalidae. All but one of these insects were collected at or near the author’s residence (Dane County); the pentatomid was taken in northern Wisconsin (Oconto County). Three of the four non-coleopteran fauna are introduced species
New Records of Coleoptera from Wisconsin
Specimens of eleven different species of beetles (one of which is identified only to genus) have been collected from and are herein reported as new to Wisconsin. These species collectively occur within seven different families: Leiodidae, Latridiidae, Scirtidae, Throscidae, Corylophidae, Staphylinidae, and Dermestidae. A majority of the specimens were collected at the author’s residence, either in pan traps or at UV lights; the others were taken at two nearby (township) parks
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Progress towards metal-free radical alkylations of quinones under mild conditions
Theoretical studies of the electronic structure of small metal clusters
Theoretical studies of the electronic structure of metal clusters, in particular clusters of Group IIA and IIB atoms were conducted. Early in the project it became clear that electron correlation involving d orbitals plays a more important role in the binding of these clusters than had been previously anticipated. This necessitated that computer codes for calculating two electron integrals and for constructing the resulting CI Hamiltonions be replaced with newer, more efficient procedures. Program modification, interfacing and testing were performed. Results of both plans are reported
Explicit correlation and basis set superposition error: The structure and energy of carbon dioxide dimer
We have investigated the slipped parallel and t-shaped structures of carbon dioxide dimer [(CO₂)₂] using both conventional and explicitly correlated coupled cluster methods, inclusive and exclusive of counterpoise (CP) correction. We have determined the geometry of both structures with conventional coupled cluster singles doubles and perturbative triples theory [CCSD(T)] and explicitly correlated cluster singles doubles and perturbative triples theory [CCSD(T)-F12b] at the complete basis set (CBS) limits using custom optimization routines. Consistent with previous investigations, we find that the slipped parallel structure corresponds to the global minimum and is 1.09 kJ mol⁻¹ lower in energy. For a given cardinal number, the optimized geometries and interaction energies of (CO₂)₂ obtained with the explicitly correlated CCSD(T)-F12b method are closer to the CBS limit than the corresponding conventional CCSD(T) results. Furthermore, the magnitude of basis set superposition error (BSSE) in the CCSD(T)-F12b optimized geometries and interaction energies is appreciably smaller than the magnitude of BSSE in the conventional CCSD(T) results. We decompose the CCSD(T) and CCSD(T)-F12b interaction energies into the constituent HF or HF CABS, CCSD or CCSD-F12b, and (T) contributions. We find that the complementary auxiliary basis set (CABS) singles correction and the F12b approximation significantly reduce the magnitude of BSSE at the HF and CCSD levels of theory, respectively. For a given cardinal number, we find that non-CP corrected, unscaled triples CCSD(T)-F12b/VXZ-F12 interaction energies are in overall best agreement with the CBS limit
Do Magnetic Fields Prevent Hydrogen from Accreting onto Cool Metal-line White Dwarf Stars?
It is generally assumed that metals detected in the spectra of a few cool
white dwarfs cannot be of primordial origin and must be accreted from the
interstellar medium. However, the observed abundances of hydrogen, which should
also be accreted from the interstellar medium, are lower than expected from
metal accretion. Magnetic fields are thought to be the reason for this
discrepancy. We have therefore obtained circular polarization spectra of the
helium-rich white dwarfs GD40 and L745-46A, which both show strong metal lines
as well as hydrogen. Whereas L745-46A might have a magnetic field of about
-6900 G, which is about two times the field strength of 3000G necessary to
repell hydrogen at the Alfen radius, only an upper limit for the field strength
of GD40 of 4000G (with 99% confidence) can be set which is far off the minimum
field strength of 144000G to repell hydrogen.Comment: 4 LaTeX pages, 4 eps figures, to appear in the proceedings of the
14th European Workshop on White Dwarfs, eds. D. Koester and S. Moehler, ASP
Conf. Serie
An efficient algorithm for calculation of the Luenberger canonical form
An algorithm is suggested to obtain the Luenberger canonical form for multivariable systems. The method computes the canonical form directly without having to compute the transformation matrix. In addition, there is a large reduction in the number of calculations. The reduced computations along with Gaussian techniques lend to greater inherent accuracy and the ability to refine the solution with additional computations
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