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Abstract-A database of magnetic susceptibility (χ) measurements on different non-ordinary chondrites (C, E, R, and ungrouped) populations is presented and compared to our previous similar work on ordinary chondrites. It provides an exhaustive study of the amount of iron-nickel magnetic phases (essentially metal and magnetite) in these meteorites. In contrast with all the other classes, CM and CV show a wide range of magnetic mineral content, with a two orders of magnitude variation of χ. Whether this is due to primary parent body differences, metamorphism or alteration, remains unclear. C3-4 and C2 yield similar χ values to the ones shown by CK and CM, respectively. By order of increasing χ, the classes with well-grouped χ are: R << CO < CK ≈ CI < Kak < CR < E ≈ CH < CB. Based on magnetism, EH and EL classes have indistinguishable metal content. Outliers that we suggest may need to have their classifications reconsidered are Acfer 202 (CO), Elephant Moraine (EET) 96026 (C4-5), Meteorite Hills (MET) 01149, and Northwest Africa (NWA) 521 (CK), Asuka (A)-88198, LaPaz Icefield (LAP) 031156, and Sahara 98248 (R). χ values can also be used to define affinities of ungrouped chondrites, and propose pairing, particularly in the case of CM and CV meteorites.

Abstract. Electrical and optical properties of binary inhomogeneous media are currently modelled by a random network of metallic bonds (conductance σ 0 , concentration p) and dielectric bonds (conductance σ 1 , concentration 1 − p). The macroscopic conductivity of this model is analytic in the complex plane of the dimensionless ratio h = σ 1 /σ 0 of the conductances of both phases, cut along the negative real axis. This cut originates in the accumulation of the resonances of clusters with any size and shape. We demonstrate that the dielectric response of an isolated cluster, or a finite set of clusters, is characterised by a finite spectrum of resonances, occurring at well-defined negative real values of h, and we define the cross-section which gives a measure of the strength of each resonance. These resonances show up as narrow peaks with Lorentzian line shapes, e.g. in the weakdissipation regime of the RL − C model. The resonance frequencies and the corresponding cross-sections only depend on the underlying lattice, on the geometry of the clusters, and on their relative positions. Our approach allows an exact determination of these characteristics. It is applied to several examples of clusters drawn on the square lattice. Scaling laws are derived analytically, and checked numerically, for the resonance spectra of linear clusters, of lattice animals, and of several examples of self-similar fractals.

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A theory of optical, infrared, and microwave response of metal-dielectric inhomogeneous films is developed. The generalized Ohm's law is formulated for the important case, when the inhomogeneity length scale is comparable with or larger than the skin ͑penetration͒ depth in metal grains. In this approach electric and magnetic fields outside a film can be related to the currents inside the film. Our computer simulations, with the use of the generalized Ohm's law approximation, reproduce the experimentally observed prominent absorption band near the percolation threshold. Calculations show that the local electric and magnetic fields experience giant spatial fluctuations. The fields are localized in small spatially separated peaks: electric and magnetic hot spots. In these hot spots the local fields ͑both electric and magnetic͒ exceed the applied field by several orders of magnitude. It is also shown that transmittance of a regular array of small holes in a metal film is strongly enhanced when the incident wave is in resonance with surface polaritons in the film. In addition, there is a skin resonance in transmission, which is of a purely geometrical nature.

PACS. 05.50.+q Lattice theory and statistics (Ising, Potts, etc.) - 05.70.-a Thermodynamics,

Statistical properties and dynamical disease propagation have been studied numerically using a percolation model in a one dimensional small world network. The parameters chosen correspond to a realistic network of school age children. It has been found that percolation threshold decreases as a power law as the shortcut fluctuations increase. It has also been found that the number of infected sites grows exponentially with time and its rate depends logarithmically on the density of susceptibles. This behavior provides an interesting way to estimate the serology for a given population from the measurement of the disease growing rate during an epidemic phase. The case in which the infection probability of nearest neighbors is different from that of short cuts has also been examined. A double diffusion behavior with a slower diffusion between the characteristic times has been found.