94 research outputs found

    The Karyology of Uraeotyphlus gansi, and Its Implications for the Systematics and Evolution of Uraeotyphlidae (Amphibia: Gymnophiona)

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    The gross karyotype of the uraeotyphlid caecilian Uraeotyphlus gansi is described as comprising 2n = 42 and fundamental number = 58. These are the first karyotype data for any species of malabaricus-group Uraeotyphlus, and the diploid number is the same as those ichthyophiids thus far studied and differs from the oxyurus-group Uraeotyphlus (2n = 36). These data support the recognition of two species groups within Uraeotyphlus, the monophyly of the oxyurus group, and the understanding that the ancestral diatriatan was more ichthyophiid-than uraeotyphlid-like. Copyright (C) 2010 S. Karger AG, Base

    The taxonomy and anatomy of rauisuchian archosaurs from the Late Triassic of Germany and Poland

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    The German Late Triassic archosaur Teratosaurus suevicus is a historically important taxon, being the first described rauisuchian. Unfortunately the holotype is a single element, a maxilla, which is poorly preserved and incomplete. We redescribe this maxilla and identify a single potential autapomorphy. The fragmentary type specimen complicates attempts to refer additional material to this taxon, and other unassociated archosaur and rauisuchian specimens from the Mittlerer Stubensandstein of Germany cannot be referred to T. suevicus with any degree of confidence. The stratigraphically older T. silesiacus, from the upper Carnian of Poland, is represented by a much more complete and better preserved specimen. Comparison of the maxillae of T. suevicus and T. silesiacus reveals that the two are distinct taxa, contra recent suggestions, but also that they do not share any synapomorphies or a unique combination of characters relative to Postosuchus kirkpatricki and other rauisuchians. Thus, the Polish material must be transferred to a new genus, Polonosuchus gen. nov. Both Polonosuchus and Teratosaurus are very similar to Postosuchus kirkpatricki, and the three taxa are likely closely related

    Phylogenetic relationships of African Caecilians (Amphibia: Gymnophiona): insights from mitochondrial rRNA gene sequences

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    Africa (excluding the Seychelles) has a diverse caecilian fauna, including the endemic family Scolecomorphidae and six endemic genera of the more cosmopolitan Caeciliidae. Previous molecular phylogenetic studies have not included any caecilians from the African mainland. Partial 12S and 16S mitochondrial gene sequences were obtained for two species of the endemic African Scolecomorphidae and five species and four genera of African Caeciliids, aligned against previously reported sequences for 16 caecilian species, and analysed using parsimony, maximum likelihood, Bayesian and distance methods. Results are in agreement with traditional taxonomy in providing support for the monophyly of the African Caeciliid genera Boulengerula and Schistometopum and for the Scolecomorphidae. They disagree in indicating that the Caeciliidae is paraphyletic with respect to the Scolecomorphidae. Although more data from morphology and/or molecules will be required to resolve details of the interrelationships of the African caecilian genera, the data provide strong support for at least two origins of caecilians in which the eye is reduced and covered with bone, and do not support the hypotheses that the caecilian assemblages of Africa, and of East and of West Africa are monophyletic

    Chemotherapy versus supportive care in advanced non-small cell lung cancer: improved survival without detriment to quality of life

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    BACKGROUND: In 1995 a meta-analysis of randomised trials investigating the value of adding chemotherapy to primary treatment for non-small cell lung cancer (NSCLC) suggested a small survival benefit for cisplatin-based chemotherapy in each of the primary treatment settings. However, the metaanalysis included many small trials and trials with differing eligibility criteria and chemotherapy regimens. METHODS: The aim of the Big Lung Trial was to confirm the survival benefits seen in the meta-analysis and to assess quality of life and cost in the supportive care setting. A total of 725 patients were randomised to receive supportive care alone (n = 361) or supportive care plus cisplatin-based chemotherapy (n = 364). RESULTS: 65% of patients allocated chemotherapy (C) received all three cycles of treatment and a further 27% received one or two cycles. 74% of patients allocated no chemotherapy (NoC) received thoracic radiotherapy compared with 47% of the C group. Patients allocated C had a significantly better survival than those allocated NoC: HR 0.77 (95% CI 0.66 to 0.89, p = 0.0006), median survival 8.0 months for the C group v 5.7 months for the NoC group, a difference of 9 weeks. There were 19 (5%) treatment related deaths in the C group. There was no evidence that any subgroup benefited more or less fromchemotherapy. No significant differences were observed between the two groups in terms of the pre-defined primary and secondary quality of life end points, although large negative effects of chemotherapy were ruled out. The regimens used proved to be cost effective, the extra cost of chemotherapy being offset by longer survival. CONCLUSIONS: The survival benefit seen in this trial was entirely consistent with the NSCLC meta-analysis and subsequent similarly designed large trials. The information on quality of life and cost should enablepatients and their clinicians to make more informed treatment choices

    Morphological evolution and modularity of the caecilian skull

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    Background: Caecilians (Gymnophiona) are the least speciose extant lissamphibian order, yet living forms capture approximately 250 million years of evolution since their earliest divergences. This long history is reflected in the broad range of skull morphologies exhibited by this largely fossorial, but developmentally diverse, clade. However, this diversity of form makes quantification of caecilian cranial morphology challenging, with highly variable presence or absence of many structures. Consequently, few studies have examined morphological evolution across caecilians. This extensive variation also raises the question of degree of conservation of cranial modules (semi-autonomous subsets of highly-integrated traits) within this clade, allowing us to assess the importance of modular organisation in shaping morphological evolution. We used an intensive surface geometric morphometric approach to quantify cranial morphological variation across all 32 extant caecilian genera. We defined 16 cranial regions using 53 landmarks and 687 curve and 729 surface sliding semilandmarks. With these unprecedented high-dimensional data, we analysed cranial shape and modularity across caecilians assessing phylogenetic, allometric and ecological influences on cranial evolution, as well as investigating the relationships among integration, evolutionary rate, and morphological disparity. Results: We found highest support for a ten-module model, with greater integration of the posterior skull. Phylogenetic signal was significant (Kmult = 0.87, p < 0.01), but stronger in anterior modules, while allometric influences were also significant (R2 = 0.16, p < 0.01), but stronger posteriorly. Reproductive strategy and degree of fossoriality were small but significant influences on cranial morphology (R2 = 0.03–0.05), after phylogenetic (p < 0.03) and multiple-test (p < 0.05) corrections. The quadrate-squamosal ‘cheek’ module was the fastest evolving module, perhaps due to its pivotal role in the unique dual jaw-closing mechanism of caecilians. Highly integrated modules exhibited both high and low disparities, and no relationship was evident between integration and evolutionary rate. Conclusions: Our high-dimensional approach robustly characterises caecilian cranial evolution and demonstrates that caecilian crania are highly modular and that cranial modules are shaped by differential phylogenetic, allometric, and ecological effects. More broadly, and in contrast to recent studies, this work suggests that there is no simple relationship between integration and evolutionary rate or disparity.Carla Bardua, Mark Wilkinson, David J. Gower, Emma Sherratt and Anjali Goswam

    High-density three-dimensional morphometric analyses support conserved static (intraspecific) modularity in caecilian (Amphibia: Gymnophiona) crania

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    Analyses of phenotypic integration and modularity seek to quantify levels of covariation among traits to identify their shared functional, developmental and genetic underpinnings (‘integration’), which may delineate semi-independent subsets of highly integrated traits (‘modules’). Existing studies have focused mainly on mammals or model organisms, limiting our understanding of factors that shape patterns of integration and modularity and their importance for morphological evolution. We present the first study of static (intraspecific) integration and modularity in caecilian crania, using dense surface sliding semi-landmarks to quantify cranial morphology in Boulengerula boulengeri and Idiocranium russeli. Eleven hypotheses of modular organization were compared with a likelihood approach and best-fitting models confirmed with covariance ratio analysis. Allometric corrections and subsampling analyses demonstrated the robustness of results. Allometry had a substantially larger influence on the results of landmark- only analyses relative to analyses incorporating semi-landmarks. Idiocranium russeli displayed significantly higher variation than B. boulengeri, but they had similar 12- and 13-module patterns, respectively, suggesting that caecilian crania are highly modular and that the modularity pattern is largely conserved across these species, despite their divergent morphologies and > 175 Myr of independent evolution. As in previous mammalian studies, our caecilian study suggests that cranial modularity patterns are conserved within major vertebrate clades.Ashleigh F. Marshall, Carla Bardua, David J. Gower, Mark Wilkinson, Emma Sherratt and Anjali Goswam

    Efficient description of shape perturbations

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    Airbus wish to have efficient ways of describing perturbations of a manu- factured aerofoil from its design shape. The typical kind of perturbations expected are waves, steps, and bumps, and automatic classification into the classes is desired. Various possible methods of analysis were pro- posed and studied in some detail, including projection onto suitable basis functions, wavelets, and radial basis functions. Other methods were studied in less detail, but with the aim of giving a digital signature of defects that could be used to classify them

    A multi-center diabetes eye screening study in community settings: Study design and methodology

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    Purpose: Diabetes is the leading cause of new cases of blindness among adults aged 20-74 years within the United States. The Innovative Network for Sight Research group (INSIGHT) designed the Diabetic Eye Screening Study (DESS) to examine the feasibility and short-term effectiveness of non-mydriatic diabetic retinopathy (DR) screening for adults with diabetes in community-based settings.Methods: Study enrollment began in December 2011 at four sites: an internal medicine clinic at a county hospital in Birmingham, Alabama; a Federally-qualified community healthcare center in Miami-Dade County, Florida; a university-affiliated outpatient pharmacy in Philadelphia, Pennsylvania; and a medical home in Winston-Salem, North Carolina. People 18 years or older with previously diagnosed diabetes were offered free DR screening using non-mydriatic retinal photography that was preceded by a brief questionnaire addressing demographic information and previous eye care use. Visual acuity was also measured for each eye. Images were evaluated at a telemedicine reading center by trained evaluators using the National Health System DR grading classification. Participants and their physicians were sent screening report results and telephoned for a follow-up survey 3 months post-screening to determine whether participants had sought follow-up comprehensive eye care and their experiences with the screening process.Results: Target enrollment at each site was a minimum of 500 persons. Three of the four sites met this enrollment goal.Conclusion: The INSIGHT/DESS is intended to establish the feasibility and short-term effectiveness of DR screening using non-mydriatic retinal photography in persons with diabetes who seek services in community-based clinic and pharmacy settings
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