219 research outputs found
The Impact of Bank Entry in the Japanese Corporate Bond Underwriting Market
The 1993 Japanese financial system reform allowed banks to enter the underwriting market for corporate bonds through bank-owned security subsidiaries. This paper examines empirically whether underwriting commissions and spreads for corporate bonds fell as a result of this bank entry. The empirical results show that bank entry significantly lowers underwriting commissions. Commissions charged by banks are significantly lower than those charged by investment houses. In contrast, there is no strong evidence that bond spreads are significantly lowered by bank entry. A main bank relationship between the issuing firm and the parent of a bank-owned underwriting subsidiary does not have any significant influence in commission setting or the determination of spreadsfinancial system reform, bank entry, bank share, commission, main bank, spread, underwriting
Three-body non-additive forces between spin-polarized alkali atoms
Three-body non-additive forces in systems of three spin-polarized alkali
atoms (Li, Na, K, Rb and Cs) are investigated using high-level ab initio
calculations. The non-additive forces are found to be large, especially near
the equilateral equilibrium geometries. For Li, they increase the three-atom
potential well depth by a factor of 4 and reduce the equilibrium interatomic
distance by 0.9 A. The non-additive forces originate principally from chemical
bonding arising from sp mixing effects.Comment: 4 pages, 3 figures (in 5 files
Photophysical and Cellular Imaging Studies of Brightly Luminescent Osmium(II) Pyridyltriazole Complexes
The series of complexes [Os(bpy)3- n(pytz) n][PF6]2 (bpy = 2,2'-bipyridyl, pytz = 1-benzyl-4-(pyrid-2-yl)-1,2,3-triazole, 1 n = 0, 2 n = 1, 3 n = 2, 4 n = 3) were prepared and characterized and are rare examples of luminescent 1,2,3-triazole-based osmium(II) complexes. For 3 we present an attractive and particularly mild preparative route via an osmium(II) η6-arene precursor circumventing the harsh conditions that are usually required. Because of the high spin-orbit coupling constant associated with the Os(II) center the absorption spectra of the complexes all display absorption bands of appreciable intensity in the range of 500-700 nm corresponding to spin-forbidden ground-state-to-3MLCT transitions (MLCT = metal-to-ligand charge transfer), which occur at significantly lower energies than the corresponding spin-allowed 1MLCT transitions. The homoleptic complex 4 is a bright emitter (λmaxem = 614 nm) with a relatively high quantum yield of emission of ∼40% in deoxygenated acetonitrile solutions at room temperature. Water-soluble chloride salts of 1-4 were also prepared, all of which remain emissive in aerated aqueous solutions at room temperature. The complexes were investigated for their potential as phosphorescent cellular imaging agents, whereby efficient excitation into the 3MLCT absorption bands at the red side of the visible range circumvents autofluorescence from biological specimens, which do not absorb in this region of the spectrum. Confocal microscopy reveals 4 to be readily taken up by cancer cell lines (HeLa and EJ) with apparent lysosomal and endosomal localization, while toxicity assays reveal that the compounds have low dark and light toxicity. These complexes therefore provide an excellent platform for the development of efficient luminescent cellular imaging agents with advantageous photophysical properties that enable excitation and emission in the biologically transparent region of the optical spectrum
Nonadiabatic approach to dimerization gap and optical absorption coefficient of the Su-Schrieffer-Heeger model
An analytical nonadiabatic approach has been developed to study the
dimerization gap and the optical absorption coefficient of the
Su-Schrieffer-Heeger model where the electrons interact with dispersive quantum
phonons. By investigating quantitatively the effects of quantum phonon
fluctuations on the gap order and the optical responses in this system, we show
that the dimerization gap is much more reduced by the quantum lattice
fluctuations than the optical absorption coefficient is. The calculated optical
absorption coefficient and the density of states do not have the
inverse-square-root singularity, but have a peak above the gap edge and there
exist a significant tail below the peak. The peak of optical absorption
spectrum is not directly corresponding to the dimerized gap. Our results of the
optical absorption coefficient agree well with those of the experiments in both
the shape and the peak position of the optical absorption spectrum.Comment: 14 pages, 7 figures. to be published in PR
Statistical Mechanics of Horizontal Gene Transfer in Evolutionary Ecology
The biological world, especially its majority microbial component, is
strongly interacting and may be dominated by collective effects. In this
review, we provide a brief introduction for statistical physicists of the way
in which living cells communicate genetically through transferred genes, as
well as the ways in which they can reorganize their genomes in response to
environmental pressure. We discuss how genome evolution can be thought of as
related to the physical phenomenon of annealing, and describe the sense in
which genomes can be said to exhibit an analogue of information entropy. As a
direct application of these ideas, we analyze the variation with ocean depth of
transposons in marine microbial genomes, predicting trends that are consistent
with recent observations using metagenomic surveys.Comment: Accepted by Journal of Statistical Physic
Helminth parasite communities of two Physalaemus cuvieri Fitzinger, 1826 (Anura: Leiuperidae) populations under different conditions of habitat integrity in the Atlantic Rain Forest of Brazil
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