Tel Aviv University

About: Tel Aviv University is a education organization based out in Tel Aviv, Israel. It is known for research contribution in the topics: Population & Medicine. The organization has 47791 authors who have published 115959 publications receiving 3904391 citations. The organization is also known as: TAU & Universiṭat Tel-Aviv.

Formulae for Determination of Chlorophyllous Pigments Extracted with N,N-Dimethylformamide

Abstract: The extraction of chlorophylls in higher plant tissue using N,N-dimethylformamide expedites the process and enables the determination of small samples with low pigment level.Absorption spectra of Chl a, Chl b, and Pchl and of their acidified derivatives, the phaeophytins, were recorded. Conversion of Chl b to its corresponding acidified product occurs much more slowly than that of Chl a and Pchl. When acidified, Pchl differs from Chl a and Chl b by the disappearance of the red band in the absorption spectrum. Specific extinction coefficients were determined and formulae for quantitative determination of pigments concentrations were developed. When concentrations of pigments are low, as in etiolated plant material, the absorption spectra of the chlorophylls can be distorted due to the presence of other substances simultaneously extracted; formulae for pigment determination under such circumstances were also derived.

Laplacian surface editing

Abstract: Surface editing operations commonly require geometric details of the surface to be preserved as much as possible. We argue that geometric detail is an intrinsic property of a surface and that, consequently, surface editing is best performed by operating over an intrinsic surface representation. We provide such a representation of a surface, based on the Laplacian of the mesh, by encoding each vertex relative to its neighborhood. The Laplacian of the mesh is enhanced to be invariant to locally linearized rigid transformations and scaling. Based on this Laplacian representation, we develop useful editing operations: interactive free-form deformation in a region of interest based on the transformation of a handle, transfer and mixing of geometric details between two surfaces, and transplanting of a partial surface mesh onto another surface. The main computation involved in all operations is the solution of a sparse linear system, which can be done at interactive rates. We demonstrate the effectiveness of our approach in several examples, showing that the editing operations change the shape while respecting the structural geometric detail.

Market Insurance, Self-Insurance, and Self-Protection

Abstract: The article develops a theory of demand for insurance that emphasizes the interaction between market insurance, “self-insurance,” and “self-protection.” The effects of changes in “prices,” income, and other variables on the demand for these alternative forms of insurance are alalyzed using the “state preference” approach to behavior under uncertainty. Market insurance and self-insurance are shown to be substitutes, but market insurance and self-protection can be complements. The analysis challenges the notion that “moral hazard” is an inevitable consequence of market insurance, by showing that under certain conditions the latter may lead to a reduction in the probabilities of hazardous events.