Almost reconstructing infinite,rayless graphs

We show that for every infinite, rayless graph G the following holds. If G is hypomorphic to H then G is isomorphic to an induced subgraph of G. This proves a conjecture of R. Halin for the class of infinite, rayless graphs and partly extends a result of Bondy and Hemminger. The proof makes use of the structure theory for rayless graphs which was developed by the author in a previous paper.     

Formation,Detection, and Reactions of Phosphinidenes (Phosphanediyls)

Formation and detection of phosphinidenes (R? P?:) in the decomposition of cyclophosphanes and in the reaction of dichlorophosphanes with metals are considered critically. Only in the thermolysis of pentaphenylcyclopentaphosphane can phenylphosphinidene be detected with certainty by pyrolysis-mass spectroscopy. “Trapping reactions” such as “insertion” into S? S or As? As bonds, and addition reactions with 1,2-diketones, 1,3-dienes, or alkynes can also be interpreted without the assumption of free phosphinidenes. The pyrolysis products of cyclophosphanes add to 1,3-dienes and alkynes, yielding five- and six-membered heterocycles that contain one to three phosphorus atoms.     

Die Charakteristik einer Halbgruppe

Ohne Zusammenfassung     

Documenting laryngeal change following prolonged loud reading: A videostroboscopic study

This study investigated the effects of prolonged loud reading on trained and untrained subjects. Subjects were eight young women singers, and eight young women with limited musical experience. Each subject underwent videostroboscopic examination prior to and following 1 h of prolonged loud reading. The pretest and posttest videotaped samples were randomized and presented to three experienced judges, who evaluated various aspects of laryngeal appearance and vibratory characteristics. Analyses of group data revealed that untrained subjects showed a small but significant increase in amplitude of vocal fold excursion following the experimental task. No significant differences were noted in the trained singer group. When individual variation was analyzed, it was found that most subjects did not show many changes from pretest to posttest. It was concluded that a l-h loud-reading task was not sufficient to induce notable laryngeal alterations     

Thermodynamics of CaCO3 phase transitions

Thermodynamic quantities of the aragonite → calcite transition, were evaluated using results of calorimetric investigations. (1) Dissolution enthalpies of the CaCO₃ polymorphs aragonite and calcite measured near room temperature with different calorimeter, (2) the enthalpy of the spontaneous phase transformation obtained by differential scanning calorimetry, (3) heat capacities and heat capacity differences determined with a heat flux calorimeter as well as previously determined, (4)e.m.f. data on Gibbs-energies of the phase transition were processed simultaneously with an optimization routine developed recently. The optimized data set (25°C) given below corresponds reasonably with CODATA recommendations, however, the precision has markedly improved.