11 research outputs found

    A fossil peat deposit from the Late Triassic (Carnian) of Zimbabwe with preserved cuticle of Pteridospermopsida and Ginkgoales, and its geological setting

    Get PDF
    Well-preserved cuticular material of Pteridospermopsida and Ginkgoales from the Late Triassic of Zimbabwe is described here for the first time. It is preserved within a brown peat-like lens in the Upper Karoo Angwa Sandstone Formation. The locality is on the Manyima River in the lower portion of the mid-Zambezi Valley of Zimbabwe. Using SEM and light microscopy to identify the taxa, the fragmentary cuticles are of Pteridospermopsida type and have been assigned to Lepidopteris sp. (Peltaspermales) and Dicroidium sp. A, B, (Corystospermales). Cuticles of the ginkgoalean leaf genus, Sphenobaiera, are also described. Well-preserved ovules were found in close association with the cuticles, but as the stomata are not visible they cannot be assigned to any genus. Based on their close similarity to the Dicroidium flora of the South African Upper Karoo, the plants are considered to be equivalent to the South African Molteno Formation in age (Carnian). The palynoflora supports this age bracket, as does fauna preserved nearby. The taphonomic process was one of transport, sorting and deposition in a fluvial system.The CNRS-NRF agreement between France and South Afric

    Writing in multi-party computer conferences and single authored assignments: Exploring the role of writer as thinker

    Full text link
    The increasing use of computers to enable or replace face-to-face tutorial discussion groups in higher education is creating a new form of academic writing. This small-scale study of 43 students and three tutors identifies ways in which students present their opinions in a forum which allows greater time for reflection, but also creates a permanent record. The notion of collaborative learning in computer conferencing militates against taking a strong, possibly controversial, stance. Opinions are therefore hedged, or located in the peer discourse community rather than the individual. Through a corpus analysis of the use of the pronouns I, we and it we identify ways in which student writers are representing themselves and their views in both computer conferences and in single-authored essays. A powerful authorial voice was often associated not with the individual I, but with the collective we. In their single-authored essays, students drew upon the consensual voice developed in the conference discussion to support their personal points of view. In both genres, students made use of impersonal it-clauses, but frequently preceded them by personal frames such as I think, thereby resisting the impersonal, but powerful, voice of much academic discourse. This paper contributes to our developing understanding of evolving student writing practices in disciplinary settings

    BHPR research: qualitative1. Complex reasoning determines patients' perception of outcome following foot surgery in rheumatoid arhtritis

    Get PDF
    Background: Foot surgery is common in patients with RA but research into surgical outcomes is limited and conceptually flawed as current outcome measures lack face validity: to date no one has asked patients what is important to them. This study aimed to determine which factors are important to patients when evaluating the success of foot surgery in RA Methods: Semi structured interviews of RA patients who had undergone foot surgery were conducted and transcribed verbatim. Thematic analysis of interviews was conducted to explore issues that were important to patients. Results: 11 RA patients (9 ♂, mean age 59, dis dur = 22yrs, mean of 3 yrs post op) with mixed experiences of foot surgery were interviewed. Patients interpreted outcome in respect to a multitude of factors, frequently positive change in one aspect contrasted with negative opinions about another. Overall, four major themes emerged. Function: Functional ability & participation in valued activities were very important to patients. Walking ability was a key concern but patients interpreted levels of activity in light of other aspects of their disease, reflecting on change in functional ability more than overall level. Positive feelings of improved mobility were often moderated by negative self perception ("I mean, I still walk like a waddling duck”). Appearance: Appearance was important to almost all patients but perhaps the most complex theme of all. Physical appearance, foot shape, and footwear were closely interlinked, yet patients saw these as distinct separate concepts. Patients need to legitimize these feelings was clear and they frequently entered into a defensive repertoire ("it's not cosmetic surgery; it's something that's more important than that, you know?”). Clinician opinion: Surgeons' post operative evaluation of the procedure was very influential. The impact of this appraisal continued to affect patients' lasting impression irrespective of how the outcome compared to their initial goals ("when he'd done it ... he said that hasn't worked as good as he'd wanted to ... but the pain has gone”). Pain: Whilst pain was important to almost all patients, it appeared to be less important than the other themes. Pain was predominately raised when it influenced other themes, such as function; many still felt the need to legitimize their foot pain in order for health professionals to take it seriously ("in the end I went to my GP because it had happened a few times and I went to an orthopaedic surgeon who was quite dismissive of it, it was like what are you complaining about”). Conclusions: Patients interpret the outcome of foot surgery using a multitude of interrelated factors, particularly functional ability, appearance and surgeons' appraisal of the procedure. While pain was often noted, this appeared less important than other factors in the overall outcome of the surgery. Future research into foot surgery should incorporate the complexity of how patients determine their outcome Disclosure statement: All authors have declared no conflicts of interes

    The relationship between pollen rain, vegetation, climate, meteorological factors and land-use in the PWV, Transvaal

    No full text
    A two-year analysis of pollen rain was conducted in the Pretoria-Witwatersrand-Vereeniging district of the Transvaal, South Africa. Poaceae WaS the major component of the pollen assemblage, comprising 52% regionally. Of the total pollen count, 58.8% was non-seasonal and present throughout the year. During the analysis it became apparent that fungal spores dominated the atmospheric content, accounting for 94% of total airspora, considered here to incl ude pollen and fUngal spores.[Abbreviated Abstract. Open document to view full version].AC201

    Organization and Evolution of a Gene-Rich Region of the Mouse Genome: A 12.7-Mb Region Deleted in the Del(13)Svea36H Mouse

    No full text
    Del(13)Svea36H (Del36H) is a deletion of ∼20% of mouse chromosome 13 showing conserved synteny with human chromosome 6p22.1-6p22.3/6p25. The human region is lost in some deletion syndromes and is the site of several disease loci. Heterozygous Del36H mice show numerous phenotypes and may model aspects of human genetic disease. We describe 12.7 Mb of finished, annotated sequence from Del36H. Del36H has a higher gene density than the draft mouse genome, reflecting high local densities of three gene families (vomeronasal receptors, serpins, and prolactins) which are greatly expanded relative to human. Transposable elements are concentrated near these gene families. We therefore suggest that their neighborhoods are gene factories, regions of frequent recombination in which gene duplication is more frequent. The gene families show different proportions of pseudogenes, likely reflecting different strengths of purifying selection and/or gene conversion. They are also associated with relatively low simple sequence concentrations, which vary across the region with a periodicity of ∼5 Mb. Del36H contains numerous evolutionarily conserved regions (ECRs). Many lie in noncoding regions, are detectable in species as distant as Ciona intestinalis, and therefore are candidate regulatory sequences. This analysis will facilitate functional genomic analysis of Del36H and provides insights into mouse genome evolution

    Short-Termism and Long-Termism

    No full text
    A significant debate in corporate law and finance concerns the role of activist investors (especially hedge funds) in corporate governance. Activists, it is often alleged, imprudently privilege short term earnings over superior (but less liquid) long term investments. Activists counter that they target managers who unjustifiably cling to questionable strategies. While this debate is hardly new, it has grown increasingly fractious of late. We analyze the activism debate within a theoretical securities-market setting. In our framework – which draws from an emerging literature in empirical and experimental finance – managers are differentially overconfident (causing them to favor long-term projects), while investors are differentially present-biased (causing them to favor short-term liquidity). We allow these biases to be either fundamental or induced by institutional factors, and they can occur either in isolation or in conjunction. Equilibrium behavior bears an uncanny resemblance to the ongoing activism debate, providing a new perspective on well-worn battle lines. Prescriptively, we demonstrate that short-termism and long-termism can have symbiotic attributes. Consequently, an optimal corporate law and governance regime should account for both effects, as well their possible interaction
    corecore