An elementary approach to dynamics and bifurcations of skew tent maps

In this paper, the dynamics of skew tent maps are classified in terms of two bifurcation parameters. In time series analysis such maps are usually referred to as continuous threshold autoregressive models (TAR(1)-models) after Tong (Non-Linear Time Series, Clarendon Press, Oxford, UK, 1990). This study contains results simplifying the use of TAR(1)-models considerably, e.g. if a periodic attractor exists it is unique. On the other hand, we also claim that care must be exercised when TAR models are used. In fact, they possess a very special type of dynamical pattern with respect to the bifurcation parameters and their transition to chaos is far from standard.     

Organische S?uren in biologischen Stoffen

Ohne Zusammenfassung     

Resolution studies on two regioisomeric chiral stationary phases: effects from reversed orientation of an amide group

Two new polymeric chiral stationary phases, incorporating the selectors trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid bis-allylamide, 1 (DEABA) and trans-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene bis-butenoylamide, 2 (DDEBB), respectively, have been evaluated by chromatographic resolution of a series of structurally different racemates. For some groups of compounds, where large separation factors were obtained, more detailed studies were performed by the use of different retention modifiers. As an effect from the reversed orientation of the amide group in the two selectors, the enantiomers of the racemates investigated are separated in opposite order of elution on the two columns.