1,882 research outputs found

    Metabolic Effect of Conjugated Oestrogens (USP) on Lipids and Lipoproteins

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    A study was undertaken to investigate the eff!!ct of conjugated oestrogens (USP) on the lipid profile of postmenopausal women. Twenty unselected menopausal women were treated for on!! year with cyclically administered oral conjugated oestrogens. Lipid studies were performed before, during and after treatment. The results showed that conjugated oestrogens had a slightly depressant effect on plasma cholesterol, b!!ta-lipoproteins, and pre-beta-lipoproteins, in both normal and hyperlipidaemic subjects. Plasma triglycerides were slightly raised during treatment in normal women, but depressed in those with baseline hypertriglyceridaemia values. None of these changes was of statistical significance. The apparent protective effect of endogenous oestrogen in the premenopause is probably related to its ability to maintain a normal lipid balance, rather than to reduce an abnormal one. This may be mediated through the known depressant effect that oestrogens have on the release of lipoprotein lipase. As a result, the breakdown of large lipid molecules to smaller particles, which could be more easily absorbed by the intima of the larger blood vessels, will be prevented

    An empirical study on the preferred size of the participant information sheet in research

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    Background: Informed consent is a requirement for all research. It is not, however, clear how much information is sufficient to make an informed decision about participation in research. Information on an online questionnaire about childhood development was provided through an unfolding electronic participant sheet in three levels of information. \ud Methods: 552 participants, who completed the web-based survey, accessed and spent time reading the participant information sheet (PIS) between July 2008 and November 2009. The information behaviour of the participants was investigated. The first level contained less information than might be found on a standard PIS, the second level corresponded to a standard PIS, and the third contained more information than on a standard PIS. The actual time spent on reading the information provided in three incremental levels and the participants' evaluation of the information were calculated. \ud Results: 77% of the participants chose to access the first level of information, whereas 12% accessed the first two levels, 6% accessed all three levels of information and 23% participated without accessing information. The most accessed levels of information were those that corresponded to the average reading times. \ud Conclusion: The brief information provided in the first level was sufficient for participants to make informed decisions, while a sizeable minority of the participants chose not to access any information at all. This study adds to the debate about how much information is required to make a decision about participation in research and the results may help inform the future development of information sheets by providing data on participants' actual needs when deciding about questionnaire surveys.\u

    How a realistic magnetosphere alters the polarizations of surface, fast magnetosonic, and Alfvén waves

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    System-scale magnetohydrodynamic (MHD) waves within Earth's magnetosphere are often understood theoretically using box models. While these have been highly instructive in understanding many fundamental features of the various wave modes present, they neglect the complexities of geospace such as the inhomogeneities and curvilinear geometries present. Here, we show global MHD simulations of resonant waves impulsively excited by a solar wind pressure pulse. Although many aspects of the surface, fast magnetosonic (cavity/waveguide), and Alfvén modes present agree with the box and axially symmetric dipole models, we find some predictions for large-scale waves are significantly altered in a realistic magnetosphere. The radial ordering of fast mode turning points and Alfvén resonant locations may be reversed even with monotonic wave speeds. Additional nodes along field lines that are not present in the displacement/velocity occur in both the perpendicular and compressional components of the magnetic field. Close to the magnetopause, the perpendicular oscillations of the magnetic field have the opposite handedness to the velocity. Finally, widely used detection techniques for standing waves, both across and along the field, can fail to identify their presence. We explain how all these features arise from the MHD equations when accounting for a non-uniform background field and propose modified methods that might be applied to spacecraft observations

    Magnetosonic ULF waves with anomalous plasma - magnetic field correlations: standing waves and inhomogeneous plasmas

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    Ultra-low frequency (ULF) wave observations across the heliosphere often rely on the sign of correlations between plasma (density/pressure) and magnetic field perturbations to distinguish between fast and slow magnetosonic modes. However, the assumptions behind this magnetohydrodynamic result are not always valid, particularly within the magnetosphere which is inhomogeneous and supports standing waves along the geomagnetic field. Through theory and a global simulation, we find both effects can result in anomalous plasma–magnetic field correlations. The interference pattern in standing waves can lead both body and surface magnetosonic waves to have different cross-phases than their constituent propagating waves. Furthermore, if the scale of gradients in the background are shorter than the wavelength or the waves are near-incompressible, then advection by the wave of inhomogeneities can overcome the wave's inherent sense of compression. These effects need to be allowed for and taken into account when applying the typical diagnostic to observations

    On the origin of high m magnetospheric waves

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    A survey of Advanced Rio-Imaging Experiment in Scandinavia data reveals evidence for a previously overlooked generation mechanism of high azimuthal wave number magnetospheric waves. Here we present observations of pulsating cosmic noise absorption with azimuthal wave numbers as high as 380, suggestive of precipitation modulation by magnetospheric waves. Dispersion relations of the small-scale precipitation pulsations are indicative of the proposed origin. Previous studies of magnetospheric waves, together with data from the Charge And Mass Magnetospheric Ion Composition Experiment (Magnetospheric Ion Composition Sensor) instrument aboard the Polar spacecraft, provide support for the theory

    Intercultural communicative competence is essential for students of international business - but can it be taught? The case of third-year BCom students

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    Intercultural communicative competence is essential for graduates wishing to work in the business sector. Such competence has become desirable for graduates who see themselves working in “demanding and highly-challenging international environments” (Sain, KuĆŸnin and Roje 2017, 55‒56). In spite of the need for well-developed intercultural competence in the workplace, students of Economic and Business Science are rarely deliberately equipped with an understanding of what language, culture and communication entail. Against this background, we investigated if an intervention, in the form of a 28-lecture undergraduate course, can develop third-year BCom students’ intercultural competence so as to prepare them to deal with the heterogeneity that they will encounter in the workplace (and elsewhere), both in multilingual and multi-cultural South Africa and abroad.Based on eight of the skills and attributes identified by Deardorff (2004) as being markers of interculturally competent individuals (such as knowledge of self and others, respect, critical thinking skills, and an awareness of the importance of being interculturally competent), students (n=18) were assessed prior to the commencement of the course and again upon completion thereof. Pre- and post-course questionnaires were analysed qualitatively and quantitatively, and data were coded according to the eight Deardorff (2004) markers of intercultural competence. Additionally, a focus group discussion (n = 5) was held at the end of the course. The data showed that development took place in the students’ attitudes, knowledge and skills related to intercultural communicative competence. Certain markers of intercultural communicative competence, however, showed more substantial development than others, the notable marker showing such development being critical thinking skills.The finding is that skills indicative of intercultural competence can indeed be developed by means of a curriculum in such a way that students think more critically about (i) cultural and linguistic diversity and (ii) their responsibility as future leaders to communicate optimally in diverse cultural settings. Deliberately including courses on intercultural communication in programmes for students (not only students in Humanities and Social Sciences) could contribute to personal and professional development of students and lead to graduates who are better prepared for a career in multicultural national and international business sectors. Likewise, the introduction of in-service training in intercultural communicative competence can be considered for those who are no longer students, thereby contributing to improved intercultural communication in the workplace

    Comparison of Two Detailed Models of Aedes aegypti Population Dynamics

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    The success of control programs for mosquito-­borne diseases can be enhanced by crucial information provided by models of the mosquito populations. Models, however, can differ in their structure, complexity, and biological assumptions, and these differences impact their predictions. Unfortunately, it is typically difficult to determine why two complex models make different predictions because we lack structured side-­by-­side comparisons of models using comparable parameterization. Here, we present a detailed comparison of two complex, spatially explicit, stochastic models of the population dynamics of Aedes aegypti, the main vector of dengue, yellow fever, chikungunya, and Zika viruses. Both models describe the mosquito?s biological and ecological characteristics, but differ in complexity and specific assumptions. We compare the predictions of these models in two selected climatic settings: a tropical and weakly seasonal climate in Iquitos, Peru, and a temperate and strongly seasonal climate in Buenos Aires, Argentina. Both models were calibrated to operate at identical average densities in unperturbedconditions in both settings, by adjusting parameters regulating densities in each model (number of larval development sites and amount of nutritional resources). We show that the models differ in their sensitivityto environmental conditions (temperature and rainfall) and trace differences to specific model assumptions.Temporal dynamics of the Ae. aegypti populations predicted by the two models differ more markedly under strongly seasonal Buenos Aires conditions. We use both models to simulate killing of larvae and/or adults with insecticides in selected areas. We show that predictions of population recovery by the models differ substantially, an effect likely related to model assumptions regarding larval development and (director delayed) density dependence. Our methodical comparison provides important guidance for model improvement by identifying key areas of Ae. aegypti ecology that substantially affect model predictions, and revealing the impact of model assumptions on population dynamics predictions in unperturbed and perturbed conditions.Fil: Legros, Mathieu. University of North Carolina; Estados UnidosFil: Otero, Marcelo Javier. Universidad de Buenos Aires; ArgentinaFil: Romeo Aznar, Victoria Teresa. Universidad de Buenos Aires; ArgentinaFil: Solari, Hernan Gustavo. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Gould, Fred. National Institutes of Health; Estados UnidosFil: Lloyd, Alun L.. National Institutes of Health; Estados Unido
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