THE MODE OF LIFE OF GORGONOPSIANS

The gorgonopsians as typically developed were undoubtedly the dominant land carnivores of the Upper Permian and have been compared with the sabre-tooth cats of the Tertiary (Parrington, 1955, p. 7 and Kemp, 1969b, p. 321). However, the similarities between the two groups are almost entirely confined to their dentitions and the general proportions of their lower jaws, both possessing greatly enlarged canine teeth and relatively weak coronoid processes on the lower jaw. In addition, both groups show adaptations to allow the lower jaw to make a wide gape, thus allowing the upper and lower canines to clear each other when the jaw is opened and, at the same time, keeping the jaw articulations from dislocating during this movement

Taxonomy of the Triassic anomodont genus Kannemeyeria

Main articleThe types of the species hitherto assigned to the genus Kannemeyeria Seeley 1908 have been re-examined and D. simocephalus Weithofer, D. latifrons Broom, K. proboscoides Seeley, Sagecephalus pachychynchus Jaekel and K. erithrea Haughton are synonymised as K. simocephalus (Weit). K. wilsoni Broom is retained as a monotypic species, but could be considered a female of K. simocephalus. The genus Kannemeyeria is redefined using the type of K. erithrea as a basis, as this specimen is complete, almost undistorted and comes from a reliably recorded locality, unlike the majority of other types. Kannemeyeria vanhoepeni Camp, while closely related to Kannemeyeria Simocephalus, has only one character in common with that species and is placed therefore in a new genus Proplacerias. This name is chosen because the specimen seem to have the characters which might be expected in a very early representative of the line leading to Placerias. K. argentinensis Bonaparte and K. latirostris Crozier are retained for valid reasons as separate species, occurring as they do in South America and Zambia respectively.The Carnegie Trust for Scottish Universities, the University of Edinburgh, the University of the Witwatersrand, Johannesburg and the C.S.I.R. of the Republic of South Africa

The affinities of Proterochampsa barrioneuvoi Reig

Proterochampsa barrioneuvoi Reig is re-examined and is confirmed as a proterosuchian thecodont. None of the features previously thought to ally it to the Crocodilia are solely characteristic of that group. On the other hand it is not a phytosaur nor phytosaur ancestor, only showing one real trend towards these animals in the rearward migration of the internal and external nares. Proterochampsa and its relatives Chanaresuchus, Gualosuchus and Cerritosaurus are too late in time to be phytosaur ancestors. They are grouped together in the Proterochampsidae, a family within the Proterosuchia.CSIR; Anderson-Capelli fund of the University of the Witwatersran

Feeding adaptations in Triassic Dicynodonts

Main articleThe Dicynodontia declined markedly at the close of the Permian, entered the Triassic with very few species and had a final burst of evolutionary success in the Middle Triassic, before being overcome by archosaurian competitors in the Upper Triassic. The structure of their skull is analysed in terms of life habit and it is concluded that in all probability the most likely close analogues to the Triassic Dicynodontia were the ground sloths of the American Neogene. Browsing and grazing modes of life are recognised. It is also postulated that tusks in the Triassic Dicynodontia were used for display purposes, and that tuskless forms were either nocturnal, or lived in thick undergrowth.Non

The skeleton of the Triassic anomodont Kannemeyeria wilsoni Broom

The general structure of the post-cranial skeleton of many Triassic anomodonts is now well known, but in Africa that of the stratigraphically important Lower Triassic (? Scythian) genus Kannemeyeria is known only from dissociated elements. A brief description is given for the first time of an almost complete skeleton ascribed to this genus. The environment of deposition is described briefly. The locality of the type species of the genus is also noted .CSIR; University of the Witwatersran

The characteristics of epidemics and invasions with thresholds

In this paper we report the development of a highly efficient numerical method for determining the principal characteristics (velocity, leading edge width, and peak height) of spatial invasions or epidemics described by deterministic one-dimensiohal reaction–diffusion models whose dynamics include a threshold or Allee effect. We prove that this methodology produces the correct results for single-component models which are generalizations of the Fisher model, and then demonstrate by numerical experimentation that analogous methods work for a wide class of epidemic and invasion models including the S–I and S–E–I epidemic models and the Rosenzweig–McArthur predator–prey model. As examplary application of this approach we consider the atto–fox effect in the classic reaction–diffusion model of rabies in the European fox population and show that the appropriate threshold for this model is within an order of magnitude of the peak disease incidence and thus has potentially significant effects on epidemic properties. We then make a careful re-parameterisation of the model and show that the velocities calculated with realistic thresholds differ surprisingly little from those calculated from threshold-free models. We conclude that an appropriately thresholded reaction–diffusion model provides a robust representation of the initial epidemic wave and thus provides a sound basis on which to begin a properly mechanistic modelling enterprise aimed at understanding the long-term persistence of the disease

Absorbate-Induced Piezochromism in a Porous Molecular Crystal

Atmospherically stable porous frameworks and materials are interesting for heterogeneous solid–gas applications. One motivation is the direct and selective uptake of pollutant/hazardous gases, where the material produces a measurable response in the presence of the analyte. In this report, we present a combined experimental and theoretical rationalization for the piezochromic response of a robust and porous molecular crystal built from an extensively fluorinated trispyrazole. The electronic response of the material is directly determined by analyte uptake, which provokes a subtle lattice contraction and an observable bathochromic shift in the optical absorption onset. Selectivity for fluorinated absorbates is demonstrated, and toluene is also found to crystallize within the pore. Furthermore, we demonstrate the application of electronic structure calculations to predict a physicochemical response, providing the foundations for the design of electronically tunable porous solids with the chemical properties required for development of novel gas-uptake media

Ultra High-Mass Resolution Paper Spray by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Paper Spray Ionization is an atmospheric pressure ionization technique that utilizes an offline electro-osmotic flow to generate ions off a paper medium. This technique can be performed on a Bruker SolariX Fourier transform ion cyclotron resonance mass spectrometer by modifying the existing nanospray source. High-resolution paper spray spectra were obtained for both organic and biological samples to demonstrate the benefit of linking the technique with a high-resolution mass analyzer. Error values in the range 0.23 to 2.14 ppm were obtained for calf lung surfactant extract with broadband mass resolving power (m/Δm50%) above 60,000 utilizing an external calibration standard

A new specimen of Dicynodon traquairi (Newton) (Synapsida: Anomodontia) from the Late Permian (Tartarian) of northern Scotland

A recently discovered natural mould of a complete, almost undistorted, skull and lower jaw of a dicynodont (c. 237mmoverall length), in a block of Upper Permian sandstone (= Dicynodon Assemblage Zone: Hopeman Sandstone Formation) from Clashach Quarry, Hopeman, Morayshire, is described using novel techniques, including Computed Tomography scanning (CT), Magnetic Resonance Imaging (MRI) and rapid-prototype modelling. It is assigned to the taxon Dicynodon traquairi (Newton, 1893). When compared with Dicynodon lacerticeps Owen, 1845, it is distinguished principally by having the pineal opening sunk deeply between the diverging parietals, subparallel pterygoid rami narrowly separated, with no transverse flanges, and in addition, a deeply grooved lower jaw symphysis. The southern African fauna lived on river flats in a higher (southern) palaeolatitude than the possibly desert-dwelling Scottish species. The Hopeman Sandstone Formation is of the same age as the better-known Cutties Hillock Sandstone Formation, whose fauna is briefly discussed and reviewed

Cytochrome P450 CYP1B1 over-expression in primary and metastatic ovarian cancer

Ovarian cancer is the most frequent cause of death from gynaecological malignancies world wide. Little improvement has been made in the long-term outcome of this disease, with the 5-year survival of patients only 30%. This poor prognosis is due to the late presentation of the disease and to the unpredictable response of ovarian cancer to chemotherapy. The cytochrome P450 enzymes are a superfamily of haemoproteins, known to be involved in the metabolic activation and/or detoxification of a number of anti-cancer drugs. CYP1B1 is a tumour-related form of cytochrome P450 which is over expressed in a wide variety of primary tumours of different histological type. The presence of CYP1B1 may be of importance in the modulation of these tumours to anti-cancer drugs. We have conducted a comprehensive immunohistochemical investigation, into the presence of cytochrome P450 CYP1B1 in primary and metastatic ovarian cancer. The key findings of this study are the increased expression of CYP1B1 in the majority of ovarian cancers investigated (92%), with a strong correlation demonstrated between CYP1B1 expression in both primary and metastatic ovarian cancer (P= 0.005 Spearman's rank correlation test). In contrast no detectable CYP1B1 was found in normal ovary. © 2001 Cancer Research Campaign http://www.bjcancer.co