Analytic parametrization of high energy forward scattering amplitude II. K±p and π±p scattering

The K^±p and π^±p forward scattering amplitudes are parametrized in terms of functions which are analytic in the cut E plane and which give the asymptotic behaviour of the total cross sections of the type c (log E/E_o)^γ, E being the lab energy. Fits to high-energy data give, in particular, the best value of γ: around it we find, however, a large interval of positive values of γ which are also admissible on the basis of the χ² estimation.Being equally good from the point of view of the existing experimental data, the different asymptotic growth rates γ do lead to different predictions, e.g., of the real part at high energies. A remarkable common feature is, however, a zero in the real part of the π⁺p and π^?p scattering amplitudes, which is predicted by all of our parametrizations to be between 52 and 80 GeV/c of the lab momentum.     

PH-Bestimmungsmethoden

Ohne Zusammenfassung     

Die Theorie der mechanischen Kolloidsynthese

Ohne Zusammenfassung The online version of the original article can be found at     

Graphical Representations of Speed: Obstacles Preservice K‐8 Teachers Experience

This study examines the difficulties college students experience when creating and interpreting graphs in which speed is one of the variables. Nineteen students, all preservice elementary or middle school teachers, completed an upper‐level course exploring algebraic concepts. Although all of these preservice teachers had previously completed several mathematics courses, including calculus, they demonstrated widespread misconceptions about the variable speed. This study identifies four cognitive obstacles held by the students, provides excerpts of their graphical constructions and verbal interpretations, and discusses potential causes for the confusion. In particular, misconceptions arose when students interpreted the behavior and nature of speed within a graphical context, as well as in situations where they were required to construct a graph involving speed as a variable. The study concludes by offering implications for the teaching and learning of speed and its interpretation within a graphical setting.     

Das ‚'Nebelverfahren“, eine neue Methode der Kolloiddarstellung

Ohne Zusammenfassung     

Study of the K+π− total cross section for c.m. energy up to 3.4 GeV

The reaction K⁺p→Δ⁺⁺(1236) + anything is studied at a beam momentum of 16.0 GeV/c. The total and topological cross sections for K⁺π^? interactions are estimated by a Chew-Low extrapolation from threshold to the c.m. energy of 3.4 GeV by the maximum likelihood method.     

Copper and iron interactions with angiotensin-converting enzyme inhibitors. A study by fast-atom bombardment tandem mass spectrometry

Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd.     

Another designer steroid: discovery, synthesis, and detection of 'madol' in urine

Madol (17alpha-methyl-5alpha-androst-2-en-17beta-ol) was identified in an oily product received by our laboratory in the context of our investigations of designer steroids. The product allegedly contained an anabolic steroid not screened for in routine sport doping control urine tests. Madol was synthesized by Grignard methylation of 5alpha-androst-2-en-17-one and characterized by mass spectrometry and NMR spectroscopy. We developed a method for rapid screening of urine samples by gas chromatography/mass spectrometry (GC/MS) of trimethylsilylated madol (monitoring m/z 143, 270, and 345). A baboon administration study showed that madol and a metabolite are excreted in urine. In vitro incubation with human liver microsomes yielded the same metabolite. Madol is only the third steroid never commercially marketed to be found in the context of performance-enhancing drugs in sports.