Generators for the tautological algebra of the moduli space of curves

In this paper, we prove that the tautological algebra in cohomology of the moduli space M_g of smooth projective curves of genus g is generated by the first [g/3] Mumford-Morita-Miller classes. This solves a part of Faber's conjecture (Moduli of Curves and Abelian Varieties Vieweg, Braunschweig, 1999) concerning the structure of the tautological algebra affirmatively. More precisely, for any k we express the kth Mumford-Morita-Miller class e_k as an explicit polynomial in the lower classes for all genera g=3k−1,3k−2,…,2.     

Determination of acetaldehyde by a chemiluminescence method

The determination of acetaldehyde was achieved by monitoring the chemiluminescence emission from the luminol-potassium hexacyanoferrate (III) reaction in the presence of xanthine oxidase. The linear range was three orders of magnitude, the detection limit (2σ) was 4 × 10^?7 M and the relative standard deviation (n = 5) was 10.6% for 4.3 × 10^?7 M. No interference was observed from seven organic and inorganic species at a 1000-fold excess relative to a concentration of 1 × 10^?5 M acetaldehyde.     

Convergent synthesis of the E'FGH' ring fragment of ciguatoxin 1B via an acetylene cobalt complex strategy

[reaction: see text] A convergent synthesis of the E'FGH' ring fragment of ciguatoxin has been accomplished through (i) coupling between the E' ring-acetylide and the H' ring-aldehyde, (ii) stereoselective F ring cyclization via an acetylene cobalt complex, (iii) conversion to a carbonyl function, and (iv) reductive hydroxy-ketone cyclization to construct the G ring.     

PREPARATION AND PROPERTIES OF CHLOROPHYLL/WATER-SOLUBLE MACROMOLECULAR COMPLEXES IN WATER. STABILIZATION OF CHLOROPHYLL AGGREGATES IN THE WATER-SOLUBLE MACROMOLECULE

Abstract— As an artificial model compound of the chlorophyll-protein complex in vivo , the chlorophyll/water-soluble macromolecular complexes were prepared by using synthetic linear polymers of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), and a natural polymer of bovine serum albumin (BSA). By the method described here, it is possible to prepare an aqueous chlorophyll (Chl)-macromolecular complex solution of a desired Chi aggregate, such as: Chi a (670), Chi a (740) and Chi b ; and with a desired relative content and concentration. These procedures for preparing such complexes will have wide applicability for technical use in Chi studies. For example, extremely diluted aqueous complex solutions of at least 1 × 10^-4% wt Chi a (670 or 740)-macromolecular complex / wt can be obtained without changing the spectral features. From viscosity measurements, the structures of the complexes were inferred: (1) for a linear macromolecular (PVA or PVP) complex, a Chi species is tightly surrounded by a chain of the polymer causing shrinkage of the chain; (2) globular BSA molecules surround Chi species to form a large complex. The mechanism of stabilization of Chi aggregates in thylakoid membrane was discussed concerning an analogy to the complexes studied here.     

A large-size silica glass produced by a new sol-gel process

A large-size silica glass was fabricated with a new sol-gel process involving the following procedures: (a) hydrolysis of Si(OC₂H₅)₄ with HCl, (b) addition of silica powders and their high dispersion, (c) adjustment of the pH value by adding ammonia solution, (d) gellation, (e) drying to dry-gel, and (f) sintering to silica glass. With this process a dry-gel plate as large as 520 x 360 mm² was obtained, which was sintered to a 420 x 290 mm² sized silica glass. The effect of pH on the gelation time of the sol, and the correlation between the weight percentage of silica powder and porosity of dry-gel were examined. In addition, fiber preforms were produced by this sol-gel process.     

Hydrothermal precipitation of ZrO2 powder

Since 1980 much attention has been payed to hydrothermal processing. There are several papers related to hydrothermal fine Zirconia powders by authors 1), 2), 3) and 3).

The authors 3) prepared ZrO₂ and Y₂O₃-ZrO₂ powders under hydrothermal conditions. Several methods were used to prepare fine ZrO₂ powders under hydrothermal conditions: hydrothermal precipatation, hydrothermal crystallization, hydrothermal oxidation, hydrothermal decomposition, hydrothermal synthesis, hydrothermal anodic oxidation, RESA (reactive electrode submerged arc) process, etc.

This paper describes hydrothermal precipatation processing of ZrO₂ and Y-ZrO₂ powder.     

Theory of optical rotation,Faraday effect,and inverse Faraday effect

The Hamiltonian for these problems is arranged appropriately in the nonrelativistic limit of the Dirac Hamiltonian. The unified view is tried to elucidate the mechanisms responsible for these phenomena by connecting the polarization vector of light and molecular properties inherent in the species or the external magnetic field. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 33–45, 1999     

Augmenting forests to meet odd diameter requirements

Given a graph G=(V,E) and an integer D≥1, we consider the problem of augmenting G by the smallest number of new edges so that the diameter becomes at most D. It is known that no constant approximation algorithms to this problem with an arbitrary graph G can be obtained unless P=NP. For a forest G and an odd D≥3, it was open whether the problem is approximable within a constant factor. In this paper, we give the first constant factor approximation algorithm to the problem with a forest G and an odd D; our algorithm delivers an 8-approximate solution in O(|V|³) time. We also show that a 4-approximate solution to the problem with a forest G and an odd D can be obtained in linear time if the augmented graph is additionally required to be biconnected.     

Reflection Asymmetric Relativistic Mean Field Approach and Its Application to the Octupole Deformed Nucleus ^226Ra

A reflection asymmetric relativistic mean field （RAS-RMF） approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-centre harmonic-oscillator potential. The efficiency and reliability of the RAS-RMF approach are demonstrated in its application to the well-known octupole deformed nucleus 226Ra and the available data, including the binding energy and the deformation parameters, are well reproduced.     

The tensor force in heavy nuclei: High momentum collectivity of unnatural parity excitations

The possibility of collectivity at high momentum transfer in unnatural parity states in finite nuclei, is outlined. This phenomenon is produced by the strong tensor force in the one pion exchange interaction operating coherently in a large oscillator space. The collectivity is observed at momentaq～(2-3)m _π corresponding to the critical momentum of pion condensation. If existent, such collective behaviour is expected to be seen in differential cross sections, e.g. for proton inelastic scattering, leading to unnatural parity states.