Dispersal kernels of butterflies: Power-law functions are invariant to marking frequency

Despite recent developments of sophisticated dispersal modelling, simple regression-based models remain useful for estimating frequencies of long-distance movements of animals. Since the inverse power function, IPF (ln I=ln C−m ln D), but not the negative exponential function, NEF (ln I=ln a−k D), exhibits the property of self-similarity, it should be robust against variation in effort invested into mark-recapture studies. We illustrate this using three data sets on movements of butterflies (Lepidoptera): Euphydryas aurinia, year 2002 (better fitted by IPF), E. aurinia, year 2003 (better fitted by NEF) and Parnassius mnemosyne (better fitted by NEF). By simulated reductions of numbers of animals, numbers of marking days, and marking effort, we show that IPF withstands severe decline in marking frequency without a change of parameters of regressions based on reduced data. In contrast, parameters of NEFs fitted to the reduced data widely varied and differed from functions based on unreduced data. Owing to the robust performance of IPF, reliable dispersal estimates may be obtained at relatively small field effort, which may facilitate quick and efficient comparisons of movement patterns among species, locations and populations.     

Interlayer Porosity in Montmorillonite Intercalated with Keggin-like Cation Studied by Molecular Mechanics Simulation

Molecular mechanics simulation using Cerius² modeling environment have been used to investigate the structure of montmorillonite, intercalated with Keggin-like cation⁷⁺. Present work is focused to the strategy of modelling in case of intercalated layered structures and to investigation of structure parameters characterizing the interlayer porosity, that means: the interlayer distance, the position, orientation and distribution of Keggin cations in the interlayer space and the stacking of layers. Molecular simulations revealed the structure of the interlayer and led to the following conclusions: In the most stable configuration the 3-fold axis of Keggin cation is perpendicular to the silicate layer. This orientation of Keggin cations leads to the basal spacing 19.51 (10^-10 m). Energy minimization during the translation of Keggin cation along the silicate layer gives only small fluctuations of basal spacing and no correlation has been found between the shift of cation along the layers and the value of basal spacing. No systematic relationship has been found between the shift of cation and crystal energy and no systematic relationship exists between the mutual shift of two successive layers and the values of basal spacing and crystal energy. Consequently, no two-dimensional ordering of Keggin cations in the interlayer and no regular stacking of layers can be expected. X-ray diffraction diagrams obtained for montmorillonites, intercalated with Keggin cation, confirm present conclusions.     

Conformational Behavior and Flexibility of Terminally Blocked Cysteine and Cystine

Conformational potential energy hypersurfaces, PES, for the terminally blocked L-Cysteine, L,L-Cystine and D,L-Cystine have been analyzed by means of molecular mechanics in combination with the programs ROSE, CICADA, PANIC and COMBINE. Low energy conformations and conformational transitions, conformational channels, have been located. Global and fragmental flexibility and conformational softness have been calculated for each conformer as well as for the entire molecule. The PES analyses were used for simulation of conformational movement based on Boltzmann probability of the points obtained on the PES. Boltzmann travelling revealed interesting correlated conformational movement where three or even more dihedral angles changed simultaneously. It could be shown that conformational behavior and flexibility were strongly influenced by the absolute configurations of the amino acids in the peptides.     

Conformational Behavior and Flexibility of Terminally Blocked Cysteine and Cystine

Conformational potential energy hypersurfaces, PES, for the terminally blocked L-Cysteine, L,L-Cystine and D,L-Cystine have been analyzed by means of molecular mechanics in combination with the programs ROSE, CICADA, PANIC and COMBINE. Low energy conformations and conformational transitions, conformational channels, have been located. Global and fragmental flexibility and conformational softness have been calculated for each conformer as well as for the entire molecule. The PES analyses were used for simulation of conformational movement based on Boltzmann probability of the points obtained on the PES. Boltzmann travelling revealed interesting correlated conformational movement where three or even more dihedral angles changed simultaneously. It could be shown that conformational behavior and flexibility were strongly influenced by the absolute configurations of the amino acids in the peptides.     

A case of translocation D-, t(lp+)

Summary A severely retarded, dystrophic, hypotonic boy with joint hyperflexibility, jaw anomalies, cerebral hypoplasia and failure to thrive is reported. He died at the age of 8 months. Clinical and biochemical investigation revealed predominantly normal values. An unusual type of palmar crease was found. Chromosomal studies showed a translocation, probably a mosaic with normal cells. The parents are chromosomally normal.