BACKGROUND AND AIMS Etiolation symptoms and the greening process are usually studied on dark-germinated seedlings and this raises the question--can these results be generalized for plants growing under field conditions? This work examines various aspects of the plastid differentiation under the covering of the achene wall, which often remains attached to the cotyledons of sunflower (Helianthus ...

Human superior and inferior venae cavae at the orifices to hearts obtained from two cadavers were histologically examined with regard to the distribution of cardiac muscle fibers in their walls. The superior vena cava contained cardiac muscle fibers together with smooth muscle fibers. The cardiac muscle fibers were distributed uninterruptedly from the atrium to the root of the azygos vein, cove...

A complete list of homogeneous operators in the Cowen Douglas class Bn(D) is given. This classification is obtained from an explicit realization of all the homogeneous Hermitian holomorphic vector bundles on the unit disc under the action of the universal covering group of the bi-holomorphic automorphism group of the unit disc.

Chain complexes with a group of operators are a well known tool in algebraic topology, where they arise naturally as the chain complex C∗X̃ of cellular chains of the universal cover X̃ of a reduced CW -complex X. The group of operators here is the fundamental group of X. J.H.C. Whitehead in his classical but little read paper [31] showed that the chain complex C∗(X̃) is useful for the homotopy cla...