SOME COMMENTS ON QUASI-INTEGRABILITY

In this paper we present our preliminary results which suggest that some field theory models are `almost` integrable; i.e. they possess a large number of `almost` conserved quantities. First we demonstrate this, in some detail, on a class of models which generalise sine-Gordon model in (1+1) dimensions. Then, we point out that many field configurations of these models look like those of the integrable systems and others are very close to being integrable. Finally we attempt to quantify these claims looking in particular, both analytically and numerically, at some long lived field configurations which resemble breathers.

Observations on ponticocythereis tricristata (Brady, 1880) from the Admiralty Islands, Papua New Guinea and comments on quaternary ostracod evolution within the sw Pacific Ocean

The ostracod species originally described as Cythere tricristata Brady, 1880 from the Admiralty Islands, Papua New Guinea, appears to belong to the SW Pacific and Australasian genus Ponticocythereis McKenzie, 1967 (sensu Warne & Whatley 1996). This interpretation is based on the presence of some posterior pointing scale-like spines on the carapace surface of this species. SEM images of the type material for Ponticocythereis tricristara n. comb., which are presented here for the first time, enable the clear differentiation of this species from the very similar Ponticocythereis ichthyoderma (Brady, 1890), Ponticocythereis quadriserialis (Brady, 1890) and Ponticocythereis laingensis (Wouters, 1981). As a consequence of the subdued manifestation of scale-like or blade-like spines on adult specimens of P. tricristata, this species closely resembles juvenile rather than adult specimens of some other Ponticocythereis species. This ontogenetic/phylogenetic relationship suggests that paedomorphic processes were significant in the Quaternary evolutionary radiation of Ponticocythereis species within tropical SW Pacific and Australasian regions.

Observations of loxocythere (loxocythere) ouyenensis (chapman, 1914) (ostracoda) from the cenozoic of S.E. Australia with comments on species attributed to microcytherura müller, 1894 and hemiparvocythere hartmann, 1982 from Australian and New Zealand ma

The type material of Loxocythere (Loxocythere) ouyenensis (Chapman, 1914) from mid Cenozoic strata of the Mallee Bore No. 11 in the Murray Basin, S.E. Australia is partially redescribed and refigured. This species belongs to a discrete group of large elongate Cenozoic fossil and living Loxocythere species, the carapaces of which possess sub-rectangular inner margin outlines, and broadly rounded posterior extremities. Some much smaller but otherwise very similarly shaped species, that have previously been placed under the genus Microcytherura (i.e. Microcytherura? peterroyi Yassini and Jones, 1995) or the genus Hemiparvocythere Hartmann, 1982 (i.e. Hemiparvocythere Iagunicola Hartmann, 1982), are also known from marine Cenozoic strata and modern seas of the Australasian region. There is a marked difference in the shape of the inner margin between this group of small Australasian forms and European species of Microcytherura s.s .. The former have broadly rounded posterior inner margins, whilst the latter have acutely rounded posterior inner margins. The latter also usually present posterior extremities located well below mid carapace height. It is here argued that this difference in inner margin shape between smaller Australasian species such as Microcytherura? peterroyi, and European species of Microcytherura s.s ., suggests that there is not a direct phylogenetic relationship between these two species groups.

Description of loxocythere (novoloxocythere) pelius subgen. sp. nov. (ostracoda) from the cenozoic of S.E. Australia with comments on species of antarctiloxoconcha hartmann, 1986 and loxoreticulatum benson, 1964 from Australian and Antarctic marine waters

Loxocythere (Novoloxocythere) pelius subgen. et sp. nov. is described from Upper Miocene strata of the Port Phillip and Western Port Basins. Victoria. It has its acme in shallow open marine facies of latest Miocene (Cheltenhamian) age. This species, along with Loxocythere (Novoloxocythere) kerryswansoni Yassini and Jones, 1995, forms a discrete group of rotund Australian Loxocythere species that possess posterior extremities in both valves that are positioned well above mid carapace height (i.e. adjacent to dorsal margin). This feature along with a sub-triangular inner margin outline, defines a carapace shape that is distinct from that of rotund species of Loxocythere (loxocythere) Hornibrook, 1952 and Antarctiloxoconcha Hartmann, 1986. The type species of Antarctiloxoconcha – A.frigida (Neale. 1967), possesses internal carapace features that are very similar to the type species of Loxocythere - L. crassa Hornibrook, 1952. Both have relatively short carapaces and sub-quadrate inner margin outlines with posterior extremities in both valves positioned below mid carapace height. Species of Loxocythere (Novoloxocythere), in particular L. (N.) kerryswansoni, have a carapace shape that is transitional between Loxocythere and Loxoreticulatum Benson, 1964. Species of Loxoreticulatum generally possess a sub-parallelogram shaped carapace/inner margin and arched median hinge element. The latter feature is distinct from the mostly straight median hinge elements of Loxocythere (Loxocythere) and Loxocythere (Novoloxocythere) species. Species of Loxocythere (Novoloxocythere) are also readily distinguishable from relatively elongate species of Loxocythere, such as L. (L.) hornibrooki McKenzie, 1967, as the latter possess long (for genus), sub-rectangular shaped carapaces/inner margin outlines and posterior extremities below mid height.

Comments on "A blind signal separation method for multiuser communications"

This correspondence first shows that the global convergence analysis of the method proposed in the above paper is incomplete. Then we provide a counter example to show that the sufficient condition for global convergence is incorrect.

Comments on 'Information measure for performance of image fusion'

The unsuitability of using classic mutual information measure as a performance measure for image fusion is discussed. Analytical proof that classic mutual information cannot be considered a measure for image fusion performance is provided.

Comments on "Adaptive multiple-surface sliding control for non-autonomous systems with mismatched uncertainties"

This note points out that the time complexity of the main multiple-surface sliding control (MSSC) algorithm in Huang and Chen [Huang, A. C. & Chen, Y. C. (2004). Adaptive multiple-surface sliding control for non-autonomous systems with mismatched uncertainties. Automatica, 40(11), 1939-1945] is O(2^n). Here, we propose a simplified recursive design MSSC algorithm with time complexity O(n), and, using mathematical induction, we show that this algorithm agrees with this MSSC law.

Comments on "finite-time stability theorem of stochastic nonlinear systems" [Automatica 46 (2010) 2105-2108]

In this comment, we will point out some errors existing in Chen and Jiao (2010) from definitions to the proof of the main result, where the authors discussed the finite-time stability of stochastic nonlinear systems and proved a Lyapunov theorem on the finitetime stability.

Description of systenobythere gen. nov. (Ostracoda, Crustacea) from the late miocene of southeastern Australia with comments on its problematical taxonomic and palaeoecological affinities

A new ostracod genus and species, Systenobythere archboldi, is described from late Miocene open neritic strata of southeastern Australia. Specimens occur in argillaceous glauconitic sands deposited in offshore continental shelf settings that were periodically influenced by coastal upwelling. Systenobythere archboldi possesses an adductor muscle scar pattern typical of the Bythocytheridae, but has a pentodont hinge and sieve-type normal pore canals atypical of this family.