A new theory of regular functions of a quaternionic variable

In this paper we develop the fundamental elements and results of a new theory of regular functions of one quaternionic variable. The theory we describe follows a classical idea of Cullen, but we use a more geometric formulation to show that it is possible to build a rather complete theory. Our theory allows us to extend some important results for polynomials in the quaternionic variable to the case of power series.     

The Sheffer group and the Riordan group

We define the Sheffer group of all Sheffer-type polynomials and prove the isomorphism between the Sheffer group and the Riordan group. An equivalence of the Riordan array pair and generalized Stirling number pair is also presented. Finally, we discuss a higher dimensional extension of Riordan array pairs.     

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.      

Analysis of Metabolites in Allantoic Fluid of Chicken Embryo by 900 MHz NMR Spectroscopy

900 MHz ¹H NMR (nuclear magnetic resonance) spectroscopy was used to analyze metabolites in allantoic fluid of the chicken embryo in the 9th incubation day without any chemical or physical sample separation. The result showed that superhigh spectral dispersion and sensitivity at 900 MHz are useful in directly analyzing a complex mixture, particularly in resolving the overlapped NMR resonances. In this study, we had assigned 61 metabolites and 26 chemical fragments in the allantoic fluid. The relative concentrations of the major metabolites were also measured. Among the assigned metabolites, some were detected by NMR in chicken embryo allantoic fluids for the first time. The biological functions of these compounds were briefly discussed. Authors' address: Maili Liu, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China     

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.     

Photoemission studies of oxygen adsorbed on a LiAl(1 1 0) alloy surface: Role of Li segregation

We investigated that the effect of the number of segregated Li atoms on the rate of oxidation on a LiAl alloy surface. Oxygen molecules adsorbed on the LiAl alloy react with the surface atoms to form stable oxides. The segregated Li atoms at reconstructed surfaces (c(2×2) and (2×1)) enhance the oxidation rate and form stable LiAlO_x and Li₂O. The degree of enhancement of oxidation by segregated Li atoms varies as a function of O₂ exposure and annealing temperature, where the latter is directly related to the mode of surface reconstruction by Li segregation.     

Master integrals for massless three-loop form factors: One-loop and two-loop insertions

The three-loop form factors in massless QCD can be expressed as a linear combination of master integrals. Besides a number of master integrals which factorise into products of one-loop and two-loop integrals, one finds 16 genuine three-loop integrals. Of these, six have the form of a bubble insertion inside a one-loop or two-loop vertex integral. We compute all master integrals with these insertion topologies.     

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.