Concentration inequalities for random fields via coupling

We present a new and simple approach to concentration inequalities in the context of dependent random processes and random fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the coupling, one obtains exponential concentration inequalities. If such a uniform control is no more possible, then one obtains polynomial or stretched-exponential concentration inequalities. Our abstract results apply to Gibbs random fields, both at high and low temperatures and in particular to the low-temperature Ising model which is a concrete example of non-uniformity of the coupling.      

On almost-sure versions of classical limit theorems for dynamical systems

The purpose of this article is to support the idea that “whenever we can prove a limit theorem in the classical sense for a dynamical system, we can prove a suitable almost-sure version based on an empirical measure with log-average”. We follow three different approaches: martingale methods, spectral methods and induction arguments. Our results apply, among others, to Axiom A maps or flows, to systems inducing a Gibbs–Markov map, and to the stadium billiard.     

Parallelization of population-based multi-objective meta-heuristics: An empirical study

In single-objective optimization it is possible to find a global optimum, while in the multi-objective case no optimal solution is clearly defined, but several that simultaneously optimize all the objectives. However, the majority of this kind of problems cannot be solved exactly as they have very large and highly complex search spaces. Recently, meta-heuristic approaches have become important tools for solving multi-objective problems encountered in industry as well as in the theoretical field. Most of these meta-heuristics use a population of solutions, and hence the runtime increases when the population size grows. An interesting way to overcome this problem is to apply parallel processing. This paper analyzes the performance of several parallel paradigms in the context of population-based multi-objective meta-heuristics. In particular, we evaluate four alternative parallelizations of the Pareto simulated annealing algorithm, in terms of quality of the solutions, and speedup.     

General Aspects and Optimization of Enantioselective Biocatalysis in Organic Solvents: The Use of Lipases [New Synthetic Methods (76)]

Enantioselective biocatalysis in nonaqueous media is becoming increasingly important in preparative synthetic chemistry. This article discusses (1) the general catalytic properties of enzymes in nonaqueous environments, (2) the basic principles that govern lipase-catalyzed enantioselective esterification and transesterification reactions in organic media for the preparation of optically active acids and alcohols, (3) the determination of kinetic and thermodynamic parameters, and (4) the quantitative analysis of published data.     

Exploring magnetic properties of ultrathin epitaxial magnetic structures using magneto-optical techniques

We describe magneto-optic Kerr effect studies of ultrathin Fe and Ni films on single crystal surfaces of Ag and Cu. Monolayer Fe films on Ag(100) exhibit the theoretically predicted spin-orbit anisotropy, but also yield some interesting discrepancies between behavior predicted by Kerr effect and by spin-polarized photoemission experiments. Layer-dependent studies of the magnetic moment of Ni on Ag(111) and Ag(100) suggest sp-d hybridization effects quench the first layer magnetic moment on Ag(111) but not on Ag(100). Temperature dependent studies of thin film magnetization obtained from Kerr effect measurements yield thickness dependent Curie temperatures, and critical exponents for several thin film systems.     

Markarian 8星系的包层辐射

使用美国甚大天线阵(VLA).对Markarian 8星系进行了多频观测.多频VLA观测表明,Markarian 8星系有三个主要的射电子成份,它们浸在一个弥漫的星系包层中.包层的射电谱是陡的非热谱.本文根据VLA观测确定了包层的物理参量,并讨论了包层中相对论性电子的可能起因.本文估计了包层非热辐射所要求的超新星爆发率.     

Maximal Cluster Sets of L-Analytic Functions Along Arbitrary Curves

Let Ώ be a domain in the N-dimensional real space, let L be an elliptic differential operator, and let (T_n) be a sequence whose members belong to a certain class of operators defined on the space of L-analytic functions on Ώ. This paper establishes the existence of a dense linear manifold of L-analytic functions all of whose nonzero members have maximal cluster sets under the action of every T_n along any curve ending at the boundary of Ώ such that its closure does not contain any component of the boundary. The above class contains all partial differentiation operators ∂^α, hence the statement extends earlier results due to Boivin, Gauthier, and Paramonov, and due to the first, third, and fourth authors.     

Generation of red light at 660 nm by frequency doubling a Nd:YAG laser with periodically-poled stoichiometric LiTaO<Subscript>3</Subscript>

High power red light was generated from a periodically-poled stoichiometric LiTaO₃ (PPSLT) by single-pass frequency doubling of a diode-side-pumped, Q-switched Nd:YAG laser at 1319 nm. An average power of 2.4 W of the 660 nm red light was obtained at the fundamental power of ∼5.4 W with the conversion efficiency up to 44.4% and with low fluctuation down to 2%. The high efficiency and stability at the red output indicate that it is a practical method to construct a reliable compact red laser. PACS 42.70.Mp; 42.79.Nv; 42.55.Xi     

Modelling aesthetic variables in the valuation of paintings: an interval goal programming approach

The economic valuation of works of art is a decisive subject in the general field of valuation. Unlike in other areas of valuation, the explanatory power of the directly observable and quantifiable variables is very low, therefore, aesthetic criteria must be used to obtain valuation models with a greater explanatory power. Frequently, these aesthetic criteria are not always precise, and experts usually express them as an interval of values. This paper describes different valuation models that use the goal programming optimisation method to include explanatory variables of the closing price in the form of intervals of values. We have also modelled the possibility that an expert can determine the relevance of each observation in the formation of the valuation function depending on the degree of precision with which the variables have been defined.     

Electronic structure of CeAl2 thin films studied by X-ray absorption spectroscopy

We report X-ray absorption near edge structures (XANES) study of CeAl₂ thin films of various thicknesses, 40-120 nm, at Al K- and Ce L₃-edges. The threshold of the absorption features at the Al K-edge shifts to the higher photon energy side as film thickness decreases, implying a decreased in Al p-orbital charges. On the other hand, from Ce L₃-edge spectra, we observed a decrease in the 5d4f occupancy as the surface-to-bulk ratio increases. The valence of Ce in these thin films, as revealed by the Ce L₃-edge spectral results, is mainly trivalent. From a more detailed analysis we found a small amount of Ce⁴⁺ contribution, which increases with decreasing film thickness. Our results indicate that the surface-to-bulk ratio is the key factor which affects the electronic structure of CeAl₂ thin films. The above observations also suggest that charge transfer from Al to Ce is associated with the decrease of the film thickness.