Triassic corals with septa that branch repeatedly and centripetally are here assigned to a new genus Furcophyllia. Septa of F. septafindens (Volz, 1896), re−described from the Italian Dolomites, are composed of 3–10 blades (“septal brooms”). Distances between adjacent septa and their branches are equal, and the thickness of all blades is approximately the same throughout ontogeny. However, none of the septal brooms show the same branching pattern. Proposed herein is a simple computer model that reproduces septal pattern, similar to that of Furcophyllia, based on a minimal set of rules: (i) uniform coverage of intra−calicular space; (ii) regular bifurcations following some probability; (iii) keeping some minimal distance between septal branches. The elaborate septal pattern of Furcophyllia suggests a distinct organization of the polyp’s soft tissue, especially mesenteries whose appearance in modern corals is associated with insertion of sclerosepta. Hypothesis 1 suggests that mesenterial pairs flanked only “septal brooms” and that septal branches functionally corresponded with septal microarchitecture. Hypothesis 2 suggests that mesenterial pairs developed between all septal branches that functionally correspond with conventional septa. Delicate menianae, which developed on Furcophyllia septal faces (and many other Triassic corals) resemble similar septal microarchitecture of the Recent agariciid Leptoseris fragilis and may be closely related to the suspension feeding strategy of this coral. The furcate septal arrangement in Furcophyllia is unique among Triassic corals, and generally, among Mesozoic and Cenozoic corals. The only analogous corals are Cretaceous aulastraeoporids (e.g., Preverastrea, Paronastraea), Trochoidomeandra, and some Jurassic rhipidogyrids having secondary (apophysal) septal branches. In some Recent caryophylliids (Trochocyathus rhombocolumna, Phacelocyathus flos) primary septa may also split dichotomously and centripetally.
The main steps in the construction of a computer model for a bacterial membrane are described. The membrane has been built of 72 lipid molecules, 54 of which being 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatidylethanolamine (POPE) and 18 - 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatidyl-rac-glycerol (POPG) molecules (thus in the proportion of 3:1). The membrane was hydrated with 1955 water molecules (approximately 27 water molecules per lipid). To neutralise the electronic charge (-e) on each POPG molecule, 18 sodium ions (Na+) were added to the membrane close to the POPG phosphate groups. The atomic charges on the POPE and POPG headgroups were obtained from ab initio quantum mechanical restrained electrostatic potential fitting (RESP) (Bayly et al., 1993, J. Phys. Chem. 97, 10269) using the GAMESS program at the 6-31G* level (Schmidt et al., 1993, J. Comput. Chem. 14, 1347). The model constructed in this way provided an initial structure for subsequent molecular dynamics simulation studies intended to elucidate the atomic level interactions responsible for the structure and dynamics of the bacterial membrane.
W artykule zaprezentowano metodykę opracowywania dynamicznego bilansu wodnogospodarczego zlewni rzecznej wraz z wykonanym na jej podstawie modelem komputerowym. Przedstawiono problemy oraz wyniki wdrożenia tego modelu dla zlewni Skawy. Model umożliwia wykonywanie ilościowych i jakościowych analiz bilansowych dla różnych wariantów zagospodarowania zasobów wodnych zlewni – zmienności potrzeb wodnych użytkowników, zabudowy hydrotechnicznej oraz wymagań utrzymania przepływów nienaruszalnych.
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