Late Silurian trace fossils from the Melbourne Formation, Studley Park, Victoria, southeastern Australia

An ichnoassemblage of 10 ichnospecies is described for the first time from the Late Silurian Melbourne Formation at Studley Park, Victoria, southeastern Australia. The ichnofauna is preserved in a typical deep-water turbidite succession of alternating thin- to thick-bedded sandstone and thin- to medium-bedded mudrocks. Trace fossils observed within the study site have been assigned to three main ichnofacies. Ichnofacies 1 is best developed on the linguoid-rippled upper surface of thin sandstone beds and includes <i>Laevicyclus, Aulichnites, Nereites, Helminthoidichnites</i>, small <i>Chondrites</i> and possible <i>Zoophycos</i>. Ichnofacies 2 is very similar to Ichnofacies 1 in ichnospecies composition but instead contains large forms of Chondrites together with other thin burrow types usually poorly preserved and in very low abundance compared with Ichnofacies 1. Ichnofacies 3 is preserved mainly as casts on the underside of medium- to thick-bedded turbiditic sandstones, and has a very low diversity, with <i>Planolites </i>being the most common trace. A detailed analysis of the ichnofabrics and tiering structures of these ichnofacies suggest that Ichnofacies 1 and 3 represent &quot;simple tiering&rsquo;, in contrast to Ichnofacies 2, which is more characteristic of 'complex tiering&rsquo;. Despite the differences in ichnospecies composition and ichnofabrics between the three recognized ichnofacies, the collective ichnoassemblage from the study site can be assigned confidently to the <i>Nereites</i> ichnofacies and is, therefore, interpreted to have formed in a distal submarine fan environment of lower bathyal to abyssal depth. Further, it is possible to recognize two main subenvironments within this deep-sea setting to account for the differences between the ichnofacies. Ichnofacies 1 and 2 are interpreted to represent a typical <i>Nereites</i> ichnofacies located on a level basin floor subenvironment of relatively low energy conditions at the distal end of a submarine fan deposit. In comparison, Ichnofacies 3 is dominated by <i>Planolites</i> with rare other facies-crossing trace fossil forms, and lacks <i>Nereites</i>. It is, therefore, best interpreted as representing a relatively high-energy environment, possibly a distributary channel near the distal end of the submarine fan system.<br />

Ordovician nautiloid fossils of Xainza region, Tibet

The Taerma bridge-Zhakang in the Xainza area is the second spot of Ordovician in northern Tibet based on the discovery of some reliable fossils. The strata contain a large amount of fossils of many taxa, which developed well enough to attain reliable support for era and distinctive boundary. It is the best spot for the fossil study of the Ordovician in the northern Tibet up to now and provides important clues to the classification and correlation of the Ordovician and to the paleogeography distribution as well as to the tectonic evolution of the northern Tibet. 29 species of Nautiloid fossils, which belong to 3 orders, 8 families and 15 genera, have been identified. Among them,3 genera and 9 species are new. Here only one new genus Eneoceras gen. nov. and six new species are described in detail as example. Other two new genera Taremaocera's and Variabioceras will be described in other papers.Genus Eneoceras gen.nov.Diagnosis:The new genus Eneoceras gen. nov. is characterized by the features as &ldquo;Conch orthoconic, medium in size. The surface is decorated with annulus which array in a distance as the septa. Conch enlarging slowly. Compressed laterally. Circular in cross section. Siphuncle small, situated central from ventral in position. Spetal neck subcyrtochoanitic. Slightly expanded in connecting rings. Siphuncle appears as a string of beads with thin parietal deposits in it. Medium in spetal density. Thin epithecal and hypothecal deposits developed in cameras<br />

New material of coral fossils in Lower Devonian, Daerdong formation of Xainza, Tibet

The system described in the part of the coral fossils collected from Xainza area, northern Lower Devonian Dahl East group. Wrinkles coral genera and 5 species (including a new species Hunanaxonia xizangensis sp nov.) And two undetermined species; bedplate coral-shaped coral 4 4 species, including two new species the (Pachycanalicula sparcula sp nov. Paraheliolites zakangensis sp nov.) these coral fossil discovery will help to further understanding of the Early Devonian corals fauna symbiotic combination, evolution, and coral paleobiogeographic flora.<br />

M'Coy and the Australian Ichthyosaur Ichthyosaurus australis (M'Coy, 1867)

The first Australian ichthyosaur fossils were described by Frederick M'Coy in 1867 from a series of fossil specimens collected by James Sutherland in the Flinders River region, northern Queensland. An initial case of fossils collected was primarily used by M'Coy to provide the first incontrovertible proof of the existence of the Cretaceous System in Australia. Subsequent follow-up work was undertaken and further specimens were collected, including fossiI vertebrae that were named by M 'Coy, lchthyosaurus australis (M'Coy 1867). Despite describing the species as 'the most interesting fossil animal yet found in Australia' his descriptions were brief and limited and have been criticized by a number of later workers.<br />

Frederick McCoy and his contributions to stratigraphical palaeontology

Sir Frederick McCoy made a significant contribution to the foundation of stratigraphical palaeontology. He carried out extensive taxonomic work sorting, naming and describing the Palaeozoic fossils of Ireland and Britain, and also played a decisive role in the debate between Adam Sedgwick and Roderick Murchison on where to draw the boundary between the Cambrian and Silurian systems. On his arrival in the Colony of Victoria in December 1854 he found that, contrary to the expectations of most European scientists, much of the stratigraphy and palaeontology paralleled that in the Northern Hemisphere. Hence McCoy was the first to confirm that the geological column was a global phenomenon.<br />

Early carboniferous athyridid brachiopods from the Qaidam Basin, Northwest China

Four new Early Carboniferous athyridid species in three genera, including one new genus, Bruntonathyris, are described from the Qaidam Basin, northwest China: Lamellosathyris qaidamensis, Bruntonathyris amunikeensis, Bruntonathyris? heijianshanensis, and Lochengia qinghaiensis. Based on the new material and also on published information, we also reviewed the taxonomic composition and the stratigraphic and paleogeographic distributions of the three genera. As a result, Lamellosathyris is considered to be indicative of late Famennian to Vis&eacute;an age, originating in late Famennian in central North America and Armenia of Russia, respectively. Later, the genus appears to have two migratory directions: one branch rapidly dispersed over Mississippi Valley, Oklahoma, Texas and New Mexico of central North America in Tournaisian; alternatively, another branch from Armenia migrated westerly to Belgium, France, Spain, Britain, Ireland, via the Moscow Basin and Ural seaway, eastward to the Tienshan Mountains and Qaidam Basin of northwest China during the Tournaisian to Vis&eacute;an, and easterly along the southern shelves of the Paleo-Tethys to Iran and western Yunnan of southwestern China in Tournaisian. Both Bruntonathyris and Lochengia are restrictedly Tournaisian to Vis&eacute;an in age, and probably originated in the Qaidam Basin. Later, Bruntonathyris migrated easterly to South China and Japan, and westerly to Urals, Moscow Basin, Donetsk Basin and Britain; Lochengia migrated easterly to South China and westerly to the Urals seaway and the adjoined Russian Platform (i.e., both the Moscow and Donetsk Basins).<br />

Knowledge extraction from a mixed transfer function artificial neural network

One of the main problems with Artificial Neural Networks (ANNs) is that their results are not intuitively clear. For example, commonly used hidden neurons with sigmoid activation function can approximate any continuous function, including linear functions, but the coefficients (weights) of this approximation are rather meaningless. To address this problem, current paper presents a novel kind of a neural network that uses transfer functions of various complexities in contrast to mono-transfer functions used in sigmoid and hyperbolic tangent networks. The presence of transfer functions of various complexities in a Mixed Transfer Functions Artificial Neural Network (MTFANN) allow easy conversion of the full model into user-friendly equation format (similar to that of linear regression) without any pruning or simplification of the model. At the same time, MTFANN maintains similar generalization ability to mono-transfer function networks in a global optimization context. The performance and knowledge extraction of MTFANN were evaluated on a realistic simulation of the Puma 560 robot arm and compared to sigmoid, hyperbolic tangent, linear and sinusoidal networks. <br />

The Permian-Triassic Boundary Stratigraphic Set: characteristics and correlation

Eased on field observations and compilation of data, a new stratigraphic concept, herein named the Permian-Triassic boundary stratigraphic set (PTBST), is proposed. The PTBST consists of, in ascending order, beds of claystone, limestone (or marl) and claystone. This boundary stratigraphic<br />set has been recognized at many sections in the Yangtze region of South China, with laterally stable lithological characters, the same or comparable biotas, comparable radiometric ages, and identical or similar magnetostratigraphic and chemostratigraphic signals. Therefore, the PTBST marks an isochronous unit and can serve as an important and effective marker set for regional and global correlations.<br />The important index fossils for the lowermost Triassic, <i>Hindeodus parvus</i> or <i>Claraia</i>, may be diachronous in their first occurrences with respect to the base of the PTBST and, therefore, should not be used as an exclusive indicator for the beginning of the Triassic. Rather more attention should<br />be paid to events, succession of events and/or event surfaces, which would potentially provide a more precise tool for high-resolution stratigraphic division and correlation.<br />

Lopingian (Late Permian) stratigraphy, sedimentation and palaeobiogeography in southern Tibet

Investigations of the Permian-Triassic sections and limestone blocks scattered in the Indus-Tsangbo Suture Zone in southern Tibet show widespread distribution of the Lopingian strata. The Lopingian deposits mostly contain rich brachiopod fossils and characteristic conodonts of the Mesogondolella shenz Zone of latest Changhsingian age in the topmost part. Brachiopod assemblages are largely comparable with those known from the upper Wargal and Chhidru Formations of the Salt Range, Pakistan, the Zewan Formation of Kashmir, the upper part of the Kuling Group in Spiti of India and the Hardman Formation of Western Australia. A revised Lopingian (Late Permian) age is proposed for the Selong Group and its equivalents in southern Tibet. The Lopingian deposits in southern Tibet can be grouped into three different sedimentary types, each of which reflects different sedimentary environments from coastal to continental shelfal settings on the northern peri-Gondwanan margin. The Qubu-type sequence represents marine coastal and proximal barrier-lagoon sediments during a gradual sea-level rise. Micaceous sandstone and shale of regressive origin, with abundant palynomorphs and acritarches, developed during the Late Lopingian sea-level lowstand, which is followed by a major rapid transgression at the very end of Permian. The Selong-type sequence in the Selong area consists of bioclastic limestone and calcareous shale in the lower part, and crinoid grainstone in the upper part. The latter part is believed to have been formed in a high-energy inner shelf shoal setting. The Chitichun-type sequence, sporadically distributed along the Indus-Tsangbo suture zone as small limestone blocks, consists of pure bioclastic sparite with the ammonoid Cyclolobus fauna. It is interpreted as the break-up products of sea-mounts and/or small isolated carbonate build-ups developed on the outer shelfal settings.<br />

Sol-gel derived HA/TiO2 double coatings on Ti scaffolds for orthopaedic applications

Hydroxyapatite/titania (HA/TiO₂) double layers were coated onto Ti scaffolds throughout for orthopaedic applications by sol-gel method. Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffractometry (XRD) were used for the characterisation of the phase transformations of the dried gels and coated surface structures. Scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS) was used for the observation and evaluation of the morphology and phases of the surface layers and for the assessment of the in vitro tests. The in vitro assessments were performed by soaking the HA/TiO₂ double coated samples into the simulated body fluid (SBF) for various periods. The TiO₂ layer was coated by a dipping-coating method at a speed of 12 cm/min, followed by a heat treatment at 600 &deg;C for 20 min. The HA layer was subsequently dipping-coated on the outer surface at the same speed and then heat-treated at difference temperatures. The results indicat that the HA phase begins to crystallize after a heat treatment at 560 &deg;C. The crystallinity increases obviously at 760 &deg;C. SEM observations find no delamination or crack at the interfaces of HA/TiO₂ and TiO₂/Ti. The HA/TiO₂ coated Ti scaffolds displays excellent bone-like apatite forming ability when it is soaked into SBF. Ti scaffolds after HA/TiO₂ double coatings can be anticipated as promising implant materials for orthopaedic applications<br />

Sol-gel derived hydroxyapatite/titania biocoatings on titanium substrate

A simple sol&ndash;gel method was successfully developed for a hydroxyapatite (HA)/TiO₂ double layer deposition on a pure titanium substrate. Phase formation, surface morphology, and interfacial microstructure were investigated by differential scanning calorimetry analysis (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TiO₂ layer was coated by a spin coating method at a speed of 1500 rpm for 15 s, followed by a heat treatment at 560 &deg;C for 20 min. The HA film was subsequently spin coated on the outer surface at the same speed and then heat-treated at difference temperatures. Results indicated that the HA phase began to crystallize after a heat treatment at 580 &deg;C; and the crystallinity increased obviously at a temperature of 780 &deg;C. The HA film showed a porous structure and a thickness of 5&ndash;7 &mu;m after the heat treatment at 780 &deg;C. SEM observations revealed no delamination and crack at the interfaces of HA/TiO₂ and TiO₂/Ti. The HA film with a porous structure is expected to be more susceptible to the natural remodeling processes when it is implanted in a living body.<br />