Naresuan University Journal
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Ageing Migrants and the Creation of Home: Mobility and the Maintenance of Transnational Ties
No full textThis paper combines two strands of literature that hitherto have often been kept separate in studies of ageing migrants: research in environmental gerontology on the one hand and work dealing with transnational migration on the other. In doing so, it aims to contribute to the understanding of the ways in which ageing migrants experience the notion of ‘home’, both as a location and a set of relationships that contribute to feelings of belonging and identity. The paper is based on 34 interviews with first-generation Turkish migrants living in inner-city districts of Brussels. The paper reviews the variety of ways in which ‘home’ is experienced and created, the constraints and environmental pressures which may prevent people from developing a sense of home, and the meaning of transnational ties and mobility for the experience of home
Existence of symmetric central configurations
No full textCentral configurations have been of great interest overmany years, with the earliest examples due to Euler and Lagrange. There are numerous results in the literature demonstrating the existence of central configurations with specific symmetry properties, using slightly different techniques in each. The aim here is to describe a uniform approach by adapting to the symmetric case the well-known variational argument showing the existence of central configurations. The principal conclusion is that there is a central configuration for every possible symmetry type, and for any symmetric choice of masses. Finally the same argument is applied to the class of balanced configurations introduced by Albouy and Chenciner
The Doubly Fed Induction Machine as an Aero Generator
No full textModern aircraft require a robust and reliable supply of electrical power to drive a growing number of high power electrical loads. Generators are driven by a mechanical offtake from the variable speed gas turbine, while a constant frequency AC network is preferred. Here doubly-fed induction machines are advantageous since they can be controlled, through a fractionally rated converter, to decouple electrical frequency from the mechanical drive speed, making control of the network frequency possible. However, the converter must be suitably rated, according to drive speed range, electrical voltage and frequency regulation, and power requirements. This paper develops and validates a simulation model of the doubly-fed induction generator system, which is applied to find the power flow through the machine’s stator and rotor connections over a wide mechanical speed range in order to size the converter. A field orientated control scheme is implemented, to provide stand-alone voltage and frequency regulation across a drive range of ±40% synchronous speed, on a purpose-built 6.6kW hardware test platform. Based on the mechanical speed range of an aero gas turbine and the identified converter sizing, the suitability of a doubly-fed induction generator for aero applications is appraised. It is shown that a converter rated at 18% of full system rating can be used to meet the aircraft electrical specifications, and offer a potential improvement in aircraft performance, with no additional mechanical components
Empirical and semi-mechanistic modelling of double-peaked pharmacokinetic profile phenomenon due to gastric emptying.
No full textModels have been developed to explain double-peaked plasma concentration-time profiles using mechanisms such as variable absorption and enterohepatic recirculation. Interruption of gastric emptying has also been shown to produce double-peaks, and this work proposes models for analysis of such data. In the presence of levodopa, gastric emptying is interrupted at times associated with double-peaks in pharmacokinetic profiles. Data from a simultaneous scintigraphy and paracetamol absorption study with levodopa was obtained, and models with compartments for stomach, intestine, central and peripheral tissue were developed to describe levodopa and paracetamol pharmacokinetics, including the double-peak phenomenon. The empirical model uses two gastric emptying parameter rates which are applied over separate time periods to describe the varying gastric emptying rate. The semi-mechanistic model uses a feedback mechanism acting via an effect compartment to link the plasma concentration of levodopa to the rate of gastric emptying, allowing levodopa pharmacokinetics to vary the rate of gastric emptying and give rise to a multiple-peaked plasma pharmacokinetic profile. The models were applied to plasma levodopa and paracetamol pharmacokinetic data with and without simultaneous analysis of scintigraphy data, in both cases giving a good fit and in the absence of scintigraphy data adequately predicting the stomach profile. For the semi-mechanistic model, the first-order constant governing gastric emptying was shown to switch between fast and slow values at a critical levodopa effect compartment concentration. New models have thus been proposed for analysis of plasma concentration profiles that exhibit double-peak phenomenon and applied successfully to levodopa data
De la etnoficción a la etnociencia ficción: transmitir las temporalidades en el cine etnográfico
No full textClassification of psychopathology and unifying theory: The ingredients of a Darwinian paradigm shift in research methodology
No full textThe field of psychopathology needs a paradigm shift to revitalise its research methodology and translational practice. We describe Darwin’s transformation of biology and its implications for science and culture, and we infer the implications of an analogous approach to psychopathology. Darwin challenged the assumptions of the biological classification system with compelling evidence to support a quantifiable, mechanistic theory of change across all life. Specifically, he showed that species were changeable, that individuals showed substantial variation in their features, and that these features were functional adaptations to the environment. Similarly, there is substantial evidence of continuous change, shared symptoms and functionality across the categories of psychiatric classification. Our novel research methodology, inspired by perceptual control theory, include both qualitative and quantitative methods, and entail the study of universal processes within heterogeneous samples and studying dynamic processes prospectively within individual cases, drawing direct analogies with evolutionary dynamic systems (e.g. trade-offs, speciation)
