On the nondegeneracy of the critical points of the Robin function in symmetric domains

2002 ◽  
Vol 335 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Massimo Grossi
2013 ◽  
Vol 40 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Anna Maria Micheletti ◽  
Angela Pistoia

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.


2000 ◽  
Vol 10 (PR5) ◽  
pp. Pr5-373-Pr5-376 ◽  
Author(s):  
A. A. Likalter ◽  
H. Schneidenbach
Keyword(s):  

Author(s):  
Elena V. Bespalova

Ancient lake sediments of Bibirevo section in the Yaroslavl and Kostroma Volga region are studied by means of graphical analysis of taxonomical structure of diatom complexes. This method allowed to record critical points (change of areas of stability) in the development of a Neopleistocene lake during the transition from stage to stage, as well as from phase to phase.


1996 ◽  
Vol 166 (6) ◽  
pp. 683-685 ◽  
Author(s):  
K.V. Kovalenko ◽  
S.V. Krivokhizha ◽  
Immanuil L. Fabelinskii ◽  
L.L. Chaikov

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