Note – On the Number of Triangulations of Planar Point Sets

n points in the plane is at most . Received: November 1, 1995     

Cation distribution of the cochlea wall (Stria vascularis)

Summary It was possible to maintain the differentiated structure of inner ear tissues by freezing in supercooled propane, freeze-drying under special conditions and embedding the tissue in a low viscosity resin. Using LAMMA we were able to measure intracellular ion concentration and concentration gradients in the soft tissues such as muscle and stria vascularis specimens. The preliminary results demonstrate that the distribution of cations in the lateral wall of the cochlear duct is not uniform. The K/Na ratio in the basal cells was significantly higher (121) than in the spiral ligament and middle part of the stria vascularis (71). Changes of such concentration ratios recorded after anoxia suggest that an energy dependent active transport mechanism must exist in the stria vascularis.

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Kationenverteilung in der Schneckengangwand des Ohres (Stria vascularis)

     

A note on the existence, uniqueness and symmetry of par-balanced realizations

We give a proof of the realization theorem of N.J. Young which states that analytic functions which are symbols of bounded Hankel operators admit par-balanced realizations. The main tool used in this proof is the induced Hilbert spaces and a lifting lemma of Kreîn-Reid-Lax-Dieudonné. Alternatively one can use the Loewner inequality. A short proof of the uniqueness of par-balanced realizations is included. As an application, it is proved that par-balanced realizations of real symmetric transfer functions areJ-self-adjoint.Research supported in part by the Romanian Academy grant GAR-6645/1996.This research was supported in part by NSF grant DMS-9501223.     

Core-Level Spectroscopy of 2-Thiouracil at the Sulfur L1- and L2,3-Edges Utilizing a SASE Free-Electron Laser

In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L₁- and L_2,3-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster–Kronig and Auger–Meitner emission at the L₁- and L_2,3-edges, respectively. We used the electron yield to construct X-ray absorption spectra at the two edges. The experimental data obtained are put in the context of the literature currently available on sulfur core-level and 2-thiouracil spectroscopy.     

Amine-Poly(Hydrogen Fluoride) Solid Complexes: New Studies of Formation,Crystal Structures,and Hn−1Fn− Ion Diversity

Triethylamine tris(hydrogen fluoride), a versatile fluorinating agent , solidifies at −27 °C forming pairs of hydrogen-bonded Et₃NH⁺ and H₂F₃⁻ ions. Six further low-melting ionic amine–HF adducts have also been identified and their structures determined. The H_n−1F_n⁻ ions with n here taking values between 3 and 7 are classified along with those observed in other crystals.     

Numerical schemes for kinematic flows with discontinuous flux

Spatially one-dimensional kinematic flows arise in a series of applications including traffic flow and sedimentation. They lead to nonlinear systems of conservation law whose flux has an explicit “concentration times velocity” structure. A new family of simple numerical schemes which are adapted to this structure, and which handle fluxes that are discontinuous with respect to the space variable, is presented and in part analyzed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectral Polarimeters Based on Integrated Acousto-Optical Ti:LiNbO3 TE-TM Converters

An integrated Ti:LiNbO3 acousto-optical TE-TM converter followed by a polarizer was used to realize a wavelength-selective polarimeter. The stop-band attenuation was shown to increase to > 28 dB when more mode converters were integrated on a chip. Based on this experience, a four-stage demonstration unit was built, and polarimetric spectra as well as the time evolution of the state of polarization were measured. Finally, a simple optical spectrum analyzer is proposed.