Modified propagation equations for soliton transmission in a polarization-division multiplexing system

The modified coupled averaged propagation equations describing the orthogonally polarized soliton propagation in a random birefringent fibre are derived. These include the third-order dispersion and Raman shift terms. Using these equations, the effects of the third-order dispersion and Raman shift terms are found to reduce the soliton interactions in a polarization-division multiplexing transmission system. This revised version was published online in November 2006 with corrections to the Cover Date.     

Macrotricyclic host molecules with basket shaped cavities

The syntheses of several macrotricyclic hexalactams (1–3) and of a corresponding hexalactone (4) are described in detail for the first time. The molecules have a basket shaped skeleton and contain a non-collapsible cavity, the size and shape of which is varied by use of spacer groups. Compounds1–3 selectively form crystalline adducts with ethanol as guest; the macrotricyclic hexaester4 does not. Evidence for an interaction of1 with ethanol was obtained by exchange experiments with perdeuteroethanol. Complexation experiments in solution did not show significant host/guest interactions with the guest chosen.     

Resonant energy exchange between atoms in dispersing and absorbing surroundings

Within the framework of quantization of a macroscopic electromagnetic field, a master equation describing both the resonant dipole-dipole interaction (RDDI) and the resonant atom-field interaction in the presence of dispersing and absorbing macroscopic bodies is derived, with the relevant couplings being expressed in terms of the surroundings-assisted Green’s tensor. It is shown that, under certain conditions, the RDDI can be regarded as being governed by an effective Hamiltonian. The theory, which applies to both weak and strong atom-field coupling, is used to study the resonant energy exchange between two (two-level) atoms initially sharing a single excitation. In particular, it is shown that, in the regime of weak atom-field coupling, there is a time window where the energy transfer follows a transfer-rate law of the type obtained by ordinary second-order perturbation theory. Finally, the spectrum of the light emitted during the energy transfer is studied and the line splittings are discussed.     

Conversion of squid pens to chitosanases and dye adsorbents via Bacillus cereus

Research on Chemical Intermediates - The purpose of this study was to reclaim squid pens for the production of chitosanases and biosorbents of food colorants and industrial dyes via Bacillus cereus...     

Chemical constituents from the fruiting bodies of Phellinus igniarius

A new tirucallane-type triterpenoid igniarine (1), and four known compounds meshimakobnol A (2), meshimakobnol B (3), ergosterol (4) and ergosterol peroxide (5), were purified from the methanol extracts of the fruiting bodies of Phellinus igniarius (DC. ex Fr.) Quél. The structure of 1 was elucidated using a combination of 1D and 2D NMR techniques and HR-ESI-MS analyses. In addition, the isolated compounds were examined for their cytotoxicity against several tumour cell lines and part of the tested compounds demonstrated weak cytotoxicity.     

Conic Linear Programming Duals for Classes of Quadratic Semi-Infinite Programs with Applications

Journal of Optimization Theory and Applications - In this paper, we first present strong conic linear programming duals for convex quadratic semi-infinite problems with linear constraints and...     

Stable splittings of

Using the Snaith-Mitchell-Priddy splittings of and , we can give new stable splittings of and
respectively.

     

On nonlinear -widths

For characterization of best nonlinear approximation, DeVore,
Howard, and Micchelli have recently suggested the nonlinear -width of a subset in a normed linear space . We proved by a topological method that for and the well-known Aleksandrov -width in a Banach space the following inequalities hold: . Let be the unit ball of Besov space , of multivariate periodic functions. Then for approximation in , with some restriction on and , we established the asymptotic degree of these -widths: .