Excitations in208Pb nearE x=5683 keV

A search for the recently proposed two-phonon octupole vibrational (2-POV) 4⁺ or 6⁺ state in²⁰⁸Pb at an excitation energy of 5683 keV has been performed using the²⁰⁷Pb(d,p),²⁰⁸Pb (p,p) and (,) reactions at high energy resolution. No evidence for a two-phonon excitation at this energy is found.This work was supported in part by the DFG under contract nr. II C4-Gr 894/2-1 and by the DFG-Graduiertenkolleg Struktur der Hadronen und Kerne under contract nr. Mu 705/3-1.     

Unilateral recurrent laryngeal nerve paralysis:The importance of “preoperative” voice therapy

This preliminary retrospective study of 19 female patients and 22male patients with unilateral recurrent nerve lesions demonstrated the promise of objective measurements in predicting the need for surgery, the efficacy of voice therapy in ameliorating vocal symptoms, and the effects of therapy in conjunction with surgery. Sixty-eight percent (68%) of the female patients and 64% of the male patients did not elect to have surgery. Outcome satisfaction of nonsurgical and surgical patients appeared to be similar. The data from this study support the importance of preoperative therapy for patients with unilateral vocal fold paralysis.     

Adaptation through minimization of the phase lag in coupled nonidentical systems

We show that the internal control of adaptation can be obtained from the properties of the phase lag that results from phase synchronization of two nonidentical chaotic oscillators. The direction and magnitude of the phase lag depend upon the relative internal properties of the coupled units, and they can be used as indicators during the adjustment of dynamics, i.e., adaptation of the target unit to match that of the control. The properties of the phase lag are obtained using a method based on the estimation of properties of the distributions of relative event times of both (target and control) units. The phase lag dependent mechanism to control the adaptation process was applied to a system of nonidentical R?ssler oscillators and a system of nonidentical Lorenz oscillators. We also elucidate its importance as a control mechanism of the changes of neuronal activity showing its application to neural adaptation.     

Über den Einfluß von einwertigen Zwischenschichtkationen auf die elektrische Leitfähigkeit von Vermikulilten in verschiedenen Hydrationszuständen (Dielektrische Messungen an Schichtsilicaten IV (1, 2, 3))

Zusammenfassung An Vermikulitkristallen mit Li⁺ und Na⁺ als Zwischenschichtkationen in verschiedenen Hydrations-zuständen (trocken, isolierte Wassermoleküle und monomolekulare Wasserschichten) wurde der Realteil der dielektrischen Permeabilitätg und der dielektrische Verlustfaktortg im Frequenzbereich zwischen 30 Hz und 10 MHz gemessen. Die elektrische Leitfähigkeit in Richtung der Schichtnormalen wird sowohl vom Hydratwasser als auch (insbesondere bei niedriger Schichtladung) von der Natur der einwertigen Zwischenschichtkationen bestimmt: Bei niederen Frequenzen und niederen Hydrationszuständen dominieren Relaxationsphänomene auf Grund der Beweglichkeit dieser Kationen. Hingegen resultiert die Leitfähigkeit in den Stufen mit isolierten Wassermolekülen und mit monomolekularen H₂O-Schichten weitgehend aus einem Wanderungsmechanismus vonL-Defekten innerhalb der Wasserstrukturen, wie er bei Vermikuliten mit zweiwertigen Kationen nachgewiesen wurde.

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Summary The dielectric permeability s' and the dielectric losstg of vermiculite crystals with Li⁺ and Na⁺ as interlayer cations in different states of hydration (completely dehydrated, with isolated water molecules and with monomolecular water layers) were measured in the frequency range between 30 Hz and 10 MHz. The electrical conductivity normal to the silicate layers was determined by the influence of the hydrate water as well as especially in the case o£ low layer charge by the nature of the monovalent interlayer cations. At low frequencies and low states of hydration it could be interpreted by a relaxation process of the interlayer cations. With isolated water molecules and with monomolecular water layers the conductivity at higher frequencies was mainly determined by a mechanism of diffusion of structuralL-defects within the water layers as in the case of hydrated vermiculites with divalent cations.

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Mit 9 Abbildungen und 2 Tabellen     

Sources of Error in Sorption and Density Measurements

In sorption measurements, volumetric or gravimetric procedures are commonly used to determine the amount adsorbed. At low pressures, thermomolecular flow and pressure differences according to Knudsen's law disturb measurements. In volumetry, calibration of the dead space is required; in gravimetry, the influence of buoyancy has to be taken into account. In both cases, adsorption of the calibrating gas, usually helium, may disturb the measurements [1]. From the calibration measurements, the density of the sample can in principle be calculated. However, it has been observed in many experiments that its value depends on the calibrating gas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination of phosphorus in fertilizers by inductively coupled plasma atomic emission spectrometry

An inductively coupled plasma atomic emission spectrometry (ICP-AES) method was developed for the determination of phosphorus in fertilizers. Total phosphorus, direct extraction available phosphorus (EDTA), and water-soluble phosphorus, reported as phosphorus pentoxide (P205), in 15 Magruder check fertilizers were measured by ICP-AES, and the results were compared with those obtained by the AOAC official method. Five analytical wavelengths of phosphorus, 177.499, 178.287, 213.618, 214.914, and 253.565 nm, were tested for the determination of phosphorus in fertilizers, and their detection limits were obtained. Acid effects of perchloric acid and possible matrix effects of aluminum, calcium, magnesium, potassium, and sodium were negligible for phosphorus determination. Wavelength 213.618 nm was the best analytical wavelength for phosphorus determination by all 3 sample preparation methods for the selected Magruder fertilizers. The results demonstrated that the accuracy and precision of the ICP-AES method were comparable with those of the official methods.     

Microscopic calculations of beta decay far from stability

Beta decay properties of nuclei far from stability are of decisive importance for the understanding of the element synthesis in the universe and the determination of the age of the universe by means of cosmochronometers. A new large scale microscopic calculation ofβ ^?-decay half-lives up to the neutron drip line is presented. This new approach uses the proton-neutron quasiparticle random phase approximation with a Gamow-Teller residual interaction.