Fixatives, Decalcifiers and Ultrastructure of the organic remnants from mural Nacreous Layers of Fossil Cephalopod Shells

The ultrastructure of the organic remnants has been compared in the TEM, after decalcification of the mural nacre of ammonites and fossil nautiloids by EDTA, which removes a soluble fraction, and after fixation and decalcification by formaldehyde-cetyl-pyridinium chloride-EDTA (CPC method) and chromium sulphate solutions, which are both considered to insure a better preservation of these organic remains. The loose networks of altered trabeculae, frequently fused into membranes, which constitute the ultrastructure of the fossil organic remnants of nacre after decalcification by EDTA, are also found in the samples treated by the CPC method and by chromium sulphate. Continuous membranes, superimposed on the networks, are especially abundant in the material treated by chromium sulphate. It is concluded that the networks of altered trabeculae are not artifacts, but are the representative ultrastructures of the organic remnants of the nacreous layers in the fossils studied so far. It is suggested that disappearance of EDTA soluble substances does not distinctly alter the ultrastructure of the fossil organic residues

Climate Change Mitigation with Technology Spillovers

We explore the implications of an increase in clean technology spillovers between developed and developing countries. We build a game of abatements in which players are linked with technology spillovers determined by an initial choice of absorptive capacities by developing countries. We show that, within a non-cooperative framework, the response of clean technology investments in developed countries to an increase in cross-country technology spillovers is ambiguous. If the marginal benefits of these additional abatements are not sufficiently high, developed countries have a strategic incentive to decrease investments. Such a strategic response jeopardizes the initial effects of an increase in technology spillovers on climate change mitigation and decreases the incentives for developing countries to enhance their absorptive capacities. © 2017, Springer Science+Business Media B.V

Multichannel coupling with supersymmetric quantum mechanics and exactly-solvable model for Feshbach resonance

A new type of supersymmetric transformations of the coupled-channel radial Schroedinger equation is introduced, which do not conserve the vanishing behavior of solutions at the origin. Contrary to usual transformations, these ``non-conservative'' transformations allow, in the presence of thresholds, the construction of potentials with coupled scattering matrices from uncoupled potentials. As an example, an exactly-solvable potential matrix is obtained which provides a very simple model of Feshbach-resonance phenomenon.Comment: 10 pages, 2 figure

Semantics of the Painted Image in Hugo von Hofmannsthal’s Tod des Tizian

Form theories in Hofmannstahl’s aesthetic program aim at a reciprocal empowerment of life and art. Titian’s last painting in Tod des Tizian (1892) has to express a concept of unity and totality of all living things. Most disciples are not able to understand this, as they can’t get free of the model of existence of the aesthete, who rejects life, perceiving it as abandoned to chaos and disorder, but is incapable of replacing it with any other form because he exalts art as an object of mere idolatry, as a pure and simple instrument of defence from the pitfalls of life

On Deterministic Sketching and Streaming for Sparse Recovery and Norm Estimation

We study classic streaming and sparse recovery problems using deterministic linear sketches, including l1/l1 and linf/l1 sparse recovery problems (the latter also being known as l1-heavy hitters), norm estimation, and approximate inner product. We focus on devising a fixed matrix A in R^{m x n} and a deterministic recovery/estimation procedure which work for all possible input vectors simultaneously. Our results improve upon existing work, the following being our main contributions: * A proof that linf/l1 sparse recovery and inner product estimation are equivalent, and that incoherent matrices can be used to solve both problems. Our upper bound for the number of measurements is m=O(eps^{-2}*min{log n, (log n / log(1/eps))^2}). We can also obtain fast sketching and recovery algorithms by making use of the Fast Johnson-Lindenstrauss transform. Both our running times and number of measurements improve upon previous work. We can also obtain better error guarantees than previous work in terms of a smaller tail of the input vector. * A new lower bound for the number of linear measurements required to solve l1/l1 sparse recovery. We show Omega(k/eps^2 + klog(n/k)/eps) measurements are required to recover an x' with |x - x'|_1 <= (1+eps)|x_{tail(k)}|_1, where x_{tail(k)} is x projected onto all but its largest k coordinates in magnitude. * A tight bound of m = Theta(eps^{-2}log(eps^2 n)) on the number of measurements required to solve deterministic norm estimation, i.e., to recover |x|_2 +/- eps|x|_1. For all the problems we study, tight bounds are already known for the randomized complexity from previous work, except in the case of l1/l1 sparse recovery, where a nearly tight bound is known. Our work thus aims to study the deterministic complexities of these problems

Mission N.M.A./PRIFAS d´etude et de prospective dans le Nordeste Bresilien: 7 au 23 juillet 1990.

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