2,835 research outputs found

    Noise Robust Blind System Identification Algorithms Based On A Rayleigh Quotient Cost Function

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    Diurnal variation in harbour porpoise detection – potential implications for management

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    Changing frames of obesity in the UK press 2008–2017

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    Obesity is a persistently newsworthy topic for the UK press and in recent years levels of coverage have increased. In this study, we examine the ways in which obesity has been framed by the press over a ten-year period (2008–2017), focussing both on areas of stability and change. The analysis is based on a ~36 million-word database of all UK newspaper articles mentioning the words ‘obese’ or ‘obesity’ published within this time frame and draws upon techniques from corpus linguistics – a collection of computational methods for examining recurrent linguistic patterns in large bodies of language data. Our analysis shows that, over time, obesity is represented increasingly as a biomedical problem that is both caused and should be prevented by individual action. Meanwhile, focus on wider environmental determinants of health, including the role of Government and the food industry, decreases over time. In the paper, we situate these trends within the wider context of UK society and argue that they both represent the increasing dominance of neoliberal models of health but also have the potential to contribute to weight stigma and the blaming of individuals. Accordingly, it is argued that the press should seek greater balance in its reporting of the potential causes of and solutions to obesity, as well as closer alignment with scientific evidence. By doing so, the press could begin to report on obesity in a way that raises useful public awareness around the topic and which challenges some of the stigma that currently attends to this social justice issue

    Exchange Splitting and Charge Carrier Spin Polarization in EuO

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    High quality thin films of the ferromagnetic semiconductor EuO have been prepared and were studied using a new form of spin-resolved spectroscopy. We observed large changes in the electronic structure across the Curie and metal-insulator transition temperature. We found that these are caused by the exchange splitting of the conduction band in the ferromagnetic state, which is as large as 0.6 eV. We also present strong evidence that the bottom of the conduction band consists mainly of majority spins. This implies that doped charge carriers in EuO are practically fully spin polarized.Comment: 4 pages, 5 figure

    Exchange bias in GeMn nanocolumns: the role of surface oxidation

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    We report on the exchange biasing of self-assembled ferromagnetic GeMn nanocolumns by GeMn-oxide caps. The x-ray absorption spectroscopy analysis of this surface oxide shows a multiplet fine structure that is typical of the Mn2+ valence state in MnO. A magnetization hysteresis shift |HE|~100 Oe and a coercivity enhancement of about 70 Oe have been obtained upon cooling (300-5 K) in a magnetic field as low as 0.25 T. This exchange bias is attributed to the interface coupling between the ferromagnetic nanocolumns and the antiferromagnetic MnO-like caps. The effect enhancement is achieved by depositing a MnO layer on the GeMn nanocolumns.Comment: 7 pages, 5 figure

    Evolution of magnetic phases and orbital occupation in (SrMnO3)n/(LaMnO3)2n superlattices

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    The magnetic and electronic modifications induced at the interfaces in (SrMnO3_{3})n_{n}/(LaMnO3_{3})2n_{2n} superlattices have been investigated by linear and circular magnetic dichroism in the Mn L2,3_{2,3} x-ray absorption spectra. Together with theoretical calculations, our data demonstrate that the charge redistribution across interfaces favors in-plane ferromagnetic (FM) order and eg(x2y2)e_{g}(x^{2}-y^{2}) orbital occupation, in agreement with the average strain. Far from interfaces, inside LaMnO3_3, electron localization and local strain favor antiferromagnetism (AFM) and eg(3z2r2)e_{g}(3z^{2}-r^{2}) orbital occupation. For n=1n=1 the high density of interfacial planes ultimately leads to dominant FM order forcing the residual AFM phase to be in-plane too, while for n5n \geq 5 the FM layers are separated by AFM regions having out-of-plane spin orientation.Comment: accepted for publication as a Rapid Communication in Physical Review

    Using conceptual metaphor and functional grammar to explore how language used in physics affects student learning

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    This paper introduces a theory about the role of language in learning physics. The theory is developed in the context of physics students' and physicists' talking and writing about the subject of quantum mechanics. We found that physicists' language encodes different varieties of analogical models through the use of grammar and conceptual metaphor. We hypothesize that students categorize concepts into ontological categories based on the grammatical structure of physicists' language. We also hypothesize that students over-extend and misapply conceptual metaphors in physicists' speech and writing. Using our theory, we will show how, in some cases, we can explain student difficulties in quantum mechanics as difficulties with language.Comment: Accepted for publication in Phys. Rev. ST:PE
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