145 research outputs found

    A late Middle Cambrian shallow-water trilobite fauna from the Mt Read Volcanics, northwestern Tasmania

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    Near Middlesex Road, 9 km northeast of the Hellyer mine, northwestern Tasmania, a mineral exploration hole intersects a polymict volcaniclastic conglomerate of the Southwell Subgroup of the Mt Read Volcanics. At depths of 353 m and 364 m, fossiliferous limestone clasts within this conglomerate contain trilobites, including an unassigned agnostoid cephalon, Amphoton sp., Liopeishania sp., Menocephalites(?) sp., Lisania(?) sp. and an unassigned member of the Dorypygidae, thus suggesting an age of Goniagnostus nathorsti Zone to early Lejopyge laevigata Zone (i.e. Late Middle Cambrian) range. This shallow-water fauna is unusual for the Tasmanian Cambrian, in which most faunas are found in deeper water shales and siltstones. The horizon from which the fossils come is stratigraphically close to a rhyolite with a SHRIMP zircon age of 503.2 ± 3.8 Ma; the usefulness of this figure in terms of the Cambrian time-scale is questioned

    Experimental and petrological studies of melt inclusions in phenocrysts from mantle-derived magmas: an overview of techniques, advantages and complications

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    Melt inclusions in phenocrysts are a potentially powerful tool in petrological research that can provide the only direct information available on the physical parameters ( P, T and melt composition) of crystallisation at various stages in the evolution of magmatic systems. However, melt inclusions also differ in principle from other parts of the magmatic system in that their composition, after trapping, may be controlled by the composition of the host phenocryst and therefore the direct application of our understanding of macro-scale magmatic processes to the interpretation of melt inclusion data can lead to erroneous conclusions. Our results indicate that the compositions of melt inclusions in early formed phenocrysts (olivine, pyroxene, plagioclase and spinel), often of most interest in petrological studies, can be affected by processes such as volatile dissociation, oxidation and/or partial re-equilibration with their host, both during natural cooling and homogenisation experiments. In particular, melt inclusions in all minerals are prone to hydrogen diffusion into or out of the inclusions after trapping and prior to eruption, and during homogenisation experiments. If not taken into account, this can significantly affect the crystallisation temperatures derived from the homogenisation experiments. Melt inclusions in highmagnesian olivine phenocrysts commonly have lower Fe contents compared to the initially trapped composition due to reequilibration with the host at lower temperatures. This often leads to the appearance of sulphide globules and in some cases high-magnesian clinopyroxene daughter crystals, and may cause an increase in the oxidation state of the inclusions. Homogenised melt inclusions in plagioclase phenocrysts in MORB usually have lower Ti and Fe, and higher Si contents compared to the melt composition at the moment of trapping. However, homogenisation experiments can provide reliable estimates of trapping temperature and the MgO, Al2O3, CaO, Na2O, and K2O contents of the host magma at the moment of trapping. Some of these processes can be identified by observing the behaviour of melt inclusions during homogenisation experiments using low-inertia visually controlled heating stages, and their effects can be minimised by using appropriate experimental conditions as determined by kinetic experiments, ideally completed for each phenocryst type in every sample. We also discuss general aspects of melt inclusion studies aimed at recovering H2O content of primary mantle-derived magmas and demonstrate that, in cases of low-pressure crystallisation, it is important to identify the first liquidus (most magnesian) olivine that crystallised from these magmas

    Elevated ad libitum alcohol consumption following continuous theta burst stimulation to the left-dorsolateral prefrontal cortex is partially mediated by changes in craving

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    Previous research indicates that following alcohol intoxication, activity in prefrontal cortices is reduced, linking to changes in associated cognitive processes, such as inhibitory control, attentional bias (AB), and craving. While these changes have been implicated in alcohol consumption behaviour, it has yet to be fully illuminated how these frontal regions and cognitive processes interact to govern alcohol consumption behaviour. The current preregistered study applied continuous theta burst transcranial magnetic stimulation (cTBS) to examine directly these relationships while removing the wider pharmacological effects of alcohol. A mixed design was implemented, with cTBS stimulation to right and left dorsolateral prefrontal cortex (DLPFC), the medial orbital frontal cortex (mOFC) and Vertex, with measures of inhibitory control, AB, and craving taken both pre- and post-stimulation. Ad libitum consumption was measured using a bogus taste task. Results suggest that rDLPFC stimulation impaired inhibitory control but did not significantly increase ad libitum consumption. However, lDLPFC stimulation heightened craving and increased consumption, with findings indicating that changes in craving partially mediated the relationship between cTBS stimulation of prefrontal regions and ad libitum consumption. Medial OFC stimulation and AB findings were inconclusive. Overall, results implicate the left DLPFC in the regulation of craving, which appears to be a prepotent cognitive mechanism by which alcohol consumption is driven and maintained

    Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

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    Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.) were leaf-labelled with 15N enriched urea during one growing season. N transfer to grasses (Lolium perenne L. and xfestulolium), white clover, red clover, lucerne, birdsfoot trefoil (Lotus corniculatus L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), salad burnet (Sanguisorba minor L.)and caraway (Carum carvi L.) was assessed. Neighbouring plants contained greater amounts of N derived from white clover (4.8 gm-2) compared with red clover (2.2 gm-2) and lucerne (1.1 gm-2). Grasses having fibrous roots received greater amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes to neighbouring plants differed among nitrogen donors and nitrogen receivers and may depend on root characteristics and regrowth strategies of plant species in the multi-species grassland

    Developing health science students into integrated health professionals: a practical tool for learning

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    BACKGROUND:An integrated sense of professionalism enables health professionals to draw on relevant knowledge in context and to apply a set of professional responsibilities and ethical principles in the midst of changing work environments 12. Inculcating professionalism is therefore a critical goal of health professional education. Two multi-professional courses for first year Health Science students at the University of Cape Town, South Africa aim to lay the foundation for becoming an integrated health professional 3. In these courses a diagram depicting the domains of the integrated health professional is used to focus the content of small group experiential exercises towards an appreciation of professionalism. The diagram serves as an organising framework for conceptualising an emerging professional identity and for directing learning towards the domains of 'self as professional' 45.OBJECTIVE:This paper describes how a diagrammatic representation of the core elements of an integrated health professional is used as a template for framing course content and for organising student learning. Based on the assumption that all health care professionals should be knowledgeable, empathic and reflective, the diagram provides students and educators with a visual tool for investigating the subjective and objective dimensions of professionalism. The use of the diagram as an integrating point of reference for individual and small group learning is described and substantiated with relevant literature. CONCLUSION: The authors have applied the diagram with positive impact for the past six years with students and educators reporting that "it just makes sense". The article includes plans for formal evaluation. Evaluation to date is based on preliminary, informal feedback on the value of the diagram as a tool for capturing the domains of professionalism at an early stage in the undergraduate education of health professional students

    Baseline mitral regurgitation predicts outcome in patients referred for dobutamine stress echocardiography

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    Purpose: A number of parameters recorded during dobutamine stress echocardiography (DSE) are associated with worse outcome. However, the relative importance of baseline mitral regurgitation (MR) is unknown. The aim of this study was to assess the prevalence and associated implications of functional MR with long-term mortality in a large cohort of patients referred for DSE. Methods: 6745 patients (mean age 64.9±12.2 years) were studied. Demographic, baseline and peak DSE data were collected. All-cause mortality was retrospectively analyzed. DSE was successfully completed in all patients with no adverse outcomes. Results: MR was present in 1019 (15.1%) patients. During a mean follow up of 5.1±1.8 years, 1642 (24.3%) patients died and MR was significantly associated with increased all-cause mortality (p<0.001). With Kaplan-Meier analysis, survival was significantly worse for patients with moderate and severe MR (p<0.001). With multivariate Cox regression analysis, moderate and severe MR (HR 2.78; 95% CI 2.17 - 3.57; and HR 3.62; 95% CI 2.89 - 4.53, respectively) were independently associated with all-cause mortality. The addition of MR to C statistic models significantly improved discrimination. Conclusions: MR is associated with all-cause mortality and adds incremental prognostic information among patients referred for DSE. The presence of MR should be taken into account when evaluating the prognostic significance of DSE results

    Effectiveness of manual therapies: the UK evidence report

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this report is to provide a succinct but comprehensive summary of the scientific evidence regarding the effectiveness of manual treatment for the management of a variety of musculoskeletal and non-musculoskeletal conditions.</p> <p>Methods</p> <p>The conclusions are based on the results of systematic reviews of randomized clinical trials (RCTs), widely accepted and primarily UK and United States evidence-based clinical guidelines, plus the results of all RCTs not yet included in the first three categories. The strength/quality of the evidence regarding effectiveness was based on an adapted version of the grading system developed by the US Preventive Services Task Force and a study risk of bias assessment tool for the recent RCTs.</p> <p>Results</p> <p>By September 2009, 26 categories of conditions were located containing RCT evidence for the use of manual therapy: 13 musculoskeletal conditions, four types of chronic headache and nine non-musculoskeletal conditions. We identified 49 recent relevant systematic reviews and 16 evidence-based clinical guidelines plus an additional 46 RCTs not yet included in systematic reviews and guidelines.</p> <p>Additionally, brief references are made to other effective non-pharmacological, non-invasive physical treatments.</p> <p>Conclusions</p> <p>Spinal manipulation/mobilization is effective in adults for: acute, subacute, and chronic low back pain; migraine and cervicogenic headache; cervicogenic dizziness; manipulation/mobilization is effective for several extremity joint conditions; and thoracic manipulation/mobilization is effective for acute/subacute neck pain. The evidence is inconclusive for cervical manipulation/mobilization alone for neck pain of any duration, and for manipulation/mobilization for mid back pain, sciatica, tension-type headache, coccydynia, temporomandibular joint disorders, fibromyalgia, premenstrual syndrome, and pneumonia in older adults. Spinal manipulation is not effective for asthma and dysmenorrhea when compared to sham manipulation, or for Stage 1 hypertension when added to an antihypertensive diet. In children, the evidence is inconclusive regarding the effectiveness for otitis media and enuresis, and it is not effective for infantile colic and asthma when compared to sham manipulation.</p> <p>Massage is effective in adults for chronic low back pain and chronic neck pain. The evidence is inconclusive for knee osteoarthritis, fibromyalgia, myofascial pain syndrome, migraine headache, and premenstrual syndrome. In children, the evidence is inconclusive for asthma and infantile colic.</p
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