Competence and performance in learning and teaching: theories and practices

For the past forty years the nature of linguistic competence has been at the centre of discussions among linguists, both theoretical and applied. This paper examines the different ways in which both competence and performance have been defined by linguists and considers how differing interpretations of these concepts have influenced foreign language learning and teaching. Special consideration is given to the role of two Council of Europe publications, the Common European Framework of Reference and the European Portfolio for Student Teachers of Languages

Studies into endogenous fibrinolysis in the peripheral and coronary vascular beds of man

BACKGROUND: Acute myocardial infarction is caused by thrombotic occlusion of a coronary artery compromised by atheromatous plaque. The interplay between acute plaque rupture or erosion and the local haemostatic and fibrinolytic activities are critical determinants in the initiation and resolution of the thrombotic complications of coronary atheroma. This is exemplified by the high rate of spontaneous reperfusion in the infarct related artery after acute myocardial infarction.OBJECTIVES: The aims of the thesis were: first, to establish a selective, specific and reproducible model for assessing endothelial function and acute endogenous fibrinolytic capacity in vivo in the peripheral circulation of man; second, to characterise the underlying mechanisms of the fibrinolytic response in this model; third, to compare the acute endogenous fibrinolytic capacity in health and disease; fourth, to examine the influence of therapeutic intervention on the fibrinolytic response; and finally, fifth, to apply this model to the coronary circulation in order to determine the acute coronary fibrinolytic response and assess its relationship with the extent of coronary atheroma.METHODS: Peripheral circulation. Blood flow and plasma fibrinolytic parameters were determined in both forearms using venous occlusion plethysmography and blood samples withdrawn from the antecubital fossae. The brachial artery of the nondominant forearm was cannulated and intra-artenal drugs administered. Plasma fibrinolytic parameters were determined using enzyme linked immunosorbant and photometric methods. The mechanisms of substance P action were explored using neurokinin type 1 receptor antagonism, nitric oxide synthase inhibition and the nitric oxide donor, sodium nitroprusside. The acute fibrinolytic response was examined in habitual cigarette smokers and patients with hypercholesterolaemia: the latter were also assessed following 6 weeks of lipid lowering therapy. Coronary circulation. Following diagnostic coronary angiography, the proximal coronary artery plaque volume was determined using computerised three dimensional reconstruction of intravascular ultrasound images. Blood flow and fibrinolytic responses to selective left anterior descending coronary artery infusion were assessed using intracoronary ultrasound and Doppler, and coronary sinus and arterial blood sampling.RESULTS: Intrabrachial substance P infusion was well tolerated and produced reproducible increases in forearm blood flow and tissue plasminogen activator release without affecting plasminogen activator inhibitor type 1 and von Willebrand factor concentrations. In contrast, endothelin-1 and L-monomethyl arginine infusion did not cause acute tissue plasminogen activator release. The response to substance P infusion appears to be dependent on the endothelial cell neurokinin type 1 receptor, and is, in part, mediated by the L-arginine:nitric oxide pathway. Whilst endothelium-dependent vasomotion was impaired in both cigarette smokers and patients with hypercholesterolaemia, tissue plasminogen activator release was diminished only in cigarette smokers and was unaffected by hypercholesterolaemia or lipid lowering therapy. Coronary fibrinolytic activity, but not endothelium-dependent coronary vasodilatation, inversely correlated with the volume of coronary artery atheroma.CONCLUSIONS: A model to assess the acute endogenous fibrinolytic capacity has been developed and characterised which was well tolerated and reproducible. Cigarette smoking, but not hypercholesterolaemia, is associated with an impairment of the acute tissue plasminogen activator release which may, in part, explain the increased propensity of smokers to sustain an acute myocardial infarction as well as to respond more favourably to thrombolytic therapy. The apparently normal fibrinolytic response in patients with hypercholesterolaemia indicates that endothelial dysfunction can be manifest in separate distinct pathways depending upon the nature of the insult. Finally, the demonstration of an association between the extent of coronary atheroma and the local endogenous fibrinolytic response provides a potentially important mechanism through which endothelial dysfunction can directly contribute to the thrombotic consequences of coronary artery disease

Vascular regulation of endogenous fibrinolysis in man

The initiation, modulation and resolution of thrombus associated with eroded or unstable coronary plaques are critical determinants of acute coronary events. This itself is dependent on the cellular function of the surrounding endothelium and vascular wall. In particular, the regulation of vascular tone and the acute release of tissue plasminogen activator by the endothelium make important contributions to the defence against intravascular thrombosis. These aspects of endothelial function will provide major new insights into the pathophysiology of cardiovascular disease, and to shape future therapeutic interventions.The experimental medicine models presented here originate from an early interest in exploring these novel aspects of endothelial function, and in particular, the acute release of the endothelium-derived fibrinolytic factor, tissue plasminogen activator. This model was initiated, developed and applied to a diverse range of physiological and pathophysiological circumstances that have informed health and disease. Publications are grouped into 5 main sections.Section 1 describes the early validation and exploration of the model to stimulate acute tissue plasminogen activator release using a variety of physiological and pathophysiological mediators. This describes the early identification of potent stimulators of acute tissue plasminogen activator release including substance P, bradykinin, desmopressin and thrombin receptor agonists. This work was extended to demonstrate the important role of nitric oxide and vascular inflammation in this process. Subsequent sections cover the application of these techniques in patient populations with a predisposition to cardiovascular disease (Section 2) as well as with established (Section 3) and end-stage disease (Section 4). These sections also explore the potentially important modulation of the renin-angiotensin system with particular reference to angiotensin-converting enzyme inhibition and the role of bradykinin. Section 5 contains some miscellaneous work and reviews of the subject area bring together the key aspects of the field as well as an important study to address the vascular endothelial function in patients with a rare haematological deficiency, type 3 von Willebrand disease

Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La_(1−x)Sr_(x)MnO_(3) (LSMO) and La_(1−x)Sr_(x)Co_(1−y)Fe_(y)O_(3) (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The surface evolution of these films is discussed, and the effects of different gas environments on oxygen vacancy concentration are elucidated. LSMO is commonly used in commercial fuel cell devices. Here the resonant soft x-ray emission (RIXS) spectrum of LSMO is examined, and it is shown that the inelastic x-ray emission structure of LSMO arises from local atomic multiplet effects

Which outcome expectancies are important in determining young adults intentions to use condoms with casual sexual partners?: A cross-sectional study

Background: The prevalence of unwanted pregnancy and sexually transmitted infection amongst young adults represents an important public health problem in the UK. Individuals attitude towards the use of condoms has been identified as an important determinant of behavioural intentions and action. The Theory of Planned Behaviour has been widely used to explain and predict health behaviour. This posits that the degree to which an individual positively or negatively values a behaviour (termed direct attitude) is based upon consideration of the likelihood of a number of outcomes occurring (outcome expectancy) weighted by the perceived desirability of those outcomes (outcome evaluation). Outcome expectancy and outcome evaluation when multiplied form indirect attitude. The study aimed to assess whether positive outcome expectancies of unprotected sex were more important for young adults with lower safe sex intentions, than those with safer sex intentions, and to isolate optimal outcomes for targeting through health promotion campaigns. Methods: A cross-sectional survey design was used. Data was collected from 1051 school and university students aged 16-24 years. Measures of intention, direct attitude and indirect attitude were taken. Participants were asked to select outcome expectancies which were most important in determining whether they would use condoms with casual sexual partners. Results: People with lower safe sex intentions were more likely than those with safer sex intentions to select all positive outcome expectancies for unprotected sex as salient, and less likely to select all negative outcome expectancies as salient. Outcome expectancies for which the greatest proportion of participants in the less safe sex group held an unfavourable position were: showing that I am a caring person, making sexual experiences less enjoyable, and protecting against pregnancy. Conclusions: The findings point to ways in which the attitudes of those with less safe sex intentions could be altered in order to motivate positive behavioural change. They suggest that it would be advantageous to highlight the potential for condom use to demonstrate a caring attitude, to challenge the potential for protected sex to reduce sexual pleasure, and to target young adults risk appraisals for pregnancy as a consequence of unprotected sex with casual sexual partners