147 research outputs found
Testing the foundations of cosmology with the radio sky
No full textSiewert T. Testing the foundations of cosmology with the radio sky. Bielefeld: Universität Bielefeld; 2021
An Interview with Hu Ching Fang
Get PDFHu Ching Fang 胡晴舫, also known as Lolita Hu, is a writer of novels, essays and short stories, who was born in 1969 in Taipei. Currently, she is the director of Kwang Hwa Information and Culture Center in Hong Kong, whose term usually lasts three years. Our conversation took place in late November 2017 in Taipei; the final version of the text was proofread and approved by the author via mail in February 2018.One of Hu’s short stories was recently published as a German translation: “Die Welt 世界”; in Thilo Diefenbach (ed./transl.): Kriegsrecht. Neue Literatur aus Taiwan. München: iudicium 2017, pp. 426–434.On the 16th September 2017, the South China Morning Post published an extensive interview with her, which is still available online. It covers both her personal life and her work as a writer, therefore I excluded these topics from my questionnaire. Additionally, numerous interviews with her can be found online in Chinese
Role of oxygen vacancies for resistive switching in noble metal sandwiched Pr<sub>0.67</sub>Ca<sub>0.33</sub>MnO<sub>3-δ</sub>
No full textNon-volatile resistance change under electric stimulation in oxides is a promising path to next generation memory devices. However, the underlying mechanisms are still not fully understood. We report here on the study of switching in Pr0.67Ca0.33MnO3-delta (PCMO) films sandwiched by noble metal Pt electrodes, where electrode oxidation can be excluded. In order to develop an understanding of the switching induced oxygen migration, its initial concentration is modified by post-annealing of the deposited PCMO films. The oxygen distribution is obtained by manganese valence determination using spatially resolved electron energy loss spectroscopy in scanning transmission electron microscopy mode. We observe correlations between virgin state resistance, resistive switching properties, oxygen vacancy distribution, and stress/strain state of the PCMO films and propose a simplified interface resistance model based on the measured valence distribution. It assumes a linear correlation of oxygen vacancy concentration with conductivity and a metal to insulator transition above a critical vacancy concentration threshold. Our results suggest that resistance changes can take place at both interfaces of symmetric devices and only requires small changes in oxygen vacancy concentration. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).DFG [Jo 348/10-01
Max Weber e il dibattito attuale sulle migrazioni
No full textMax Weber and the Current Debate on Migration. Drawing on Max Weber’s famous Antrittsvorlesung (1895), the author develops an ideal type framework to categorize various perspectives on the migration issue. Based on two contrasting attitudes – the axiological-differential and the universal-relativistic – the author critically examines the positions of Thilo Sarrazin, Bassam Tibi, and Aladdin El-Mafaalani
Review of Stevenson, Roland C. (author) & Thilo Schadeberg (editor): Tira and Otoro, two Kordofanian Grammars by Roland C. Stevenson. (Archiv afrikanistischer Manuskripte, 8) Rüdiger Köppe Verlag, Köln 2009. 333 pp. Price € 48,-. ISBN 978-3-89645-173-6.
Get PDFInternational audienceToday, the Kordofanian family of the Niger-Congo phylum remains one of the most poorly researched language families in Africa and worldwide. This book makes two descriptive grammars available to the scientific community, respectively Tira and Otoro (both of which belonging to the Heibanian branch of Kordofanian) and is therefore a most welcome publication.The author of those grammars, Roland C. Stevenson (1915‒1991), is a member of the Church Missionary Society, who first arrived in Sudan in 1937 and soon got involved in the study of various Sudanese tongues. He devoted his PhD (Stevenson 1956-57) to the languages spoken in the Nuba Mountains, a region which is the home area of all attested Kordofanian languages. As “descriptive and comparative work on Kordofanian languages is still in its infancy” (Schadeberg 1989: 79), Stevenson’s abundant linguistic production remains one of the main sources (and in some cases the only one) available for many Kordofanian languages.The editor of these grammars, Thilo Schadeberg, is one of the very few linguists to have regularly worked and published on Kordofanian languages (e.g. Schadeberg 1981a/b, 1989) since the second half of the XXth century. As explained in the preface of the book, Stevenson wrote his Tira (TI) and Otoro (OT) grammars in 1942 and 1943 respectively. However, these existed only as typescripts and it is thanks to Schadeberg’s efforts that “the data and analyses” they contain are “presented here [i.e. in this book] for the first time in print” (p. viii)
Cosmic radio dipole: Estimators and frequency dependence
No full textSiewert T, Schmidt-Rubart M, Schwarz D. Cosmic radio dipole: Estimators and frequency dependence. Astronomy and Astrophysics. 2021;653: A9.The cosmic radio dipole is of fundamental interest to studies of cosmology. Recent works have put forth open questions about the nature of the observed cosmic radio dipole. In the current work, we use simulated source count maps to test a linear and a quadratic estimator for possible biases in the estimated dipole amplitude with respect to the masking procedure. We find a superiority on the part of the quadratic estimator, which we used to analyse the TGSS-ADR1, WENSS, SUMSS, and NVSS radio source catalogues, spread over a decade of frequencies. We applied the same masking strategy to all four surveys to produce comparable results. In order to address the differences in the observed dipole amplitudes, we cross-matched the two surveys located at both ends of the analysed frequency range. For the linear estimator, we identified a general bias in the estimated dipole directions. The positional offsets of the quadratic estimator to the cosmic microwave background (CMB) dipole for skies with 10(7) simulated sources is found to be below one degree and the absolute accuracy of the estimated dipole amplitudes is better than 10(-3). For the four radio source catalogues, we find an increasing dipole amplitude with decreasing frequency, which is consistent with results from the literature and the results of the cross-matched catalogue. We conclude that for all analysed surveys, the observed cosmic radio dipole amplitudes exceed the expectations derived from the CMB dipole, which cannot strictly be explained by a kinematic dipole alone
Testing the standard model of cosmology with the SKA: the cosmic radio dipole
No full textBengaly CAP, Siewert T, Schwarz D, Maartens R. Testing the standard model of cosmology with the SKA: the cosmic radio dipole. Monthly Notices of the Royal Astronomical Society. 2019;486(1):1350-1357.The dipole anisotropy seen in the cosmic microwave background (CMB) radiation is interpreted as due to our peculiar motion. The cosmological principle implies that this cosmic dipole signal should also be present, with the same direction, in the large-scale distribution of matter. Measurement of the cosmic matter dipole constitutes a key test of the standard cosmological model. Current measurements of this dipole are barely above the expected noise and unable to provide a robust test. Upcoming radio continuum surveys with the SKA should be able to detect the dipole at high signal to noise. We simulate number count maps for SKA survey specifications in Phases 1 and 2, including all relevant effects. Non-linear effects from local large-scale structure contaminate the cosmic (kinematic) dipole signal, and we find that removal of radio sources at low redshift (z less than or similar to 0.5) leads to significantly improved constraints. We forecast that the SKA could determine the kinematic dipole direction in Galactic coordinates with an error of (Delta l, Delta b) similar to (9 degrees, 5 degrees) to (8 degrees, 4 degrees), depending on the sensitivity. The predicted errors on the relative speed are similar to 10 per cent. These measurements would significantly reduce the present uncertainty on the direction of the radio dipole, and thus enable the first critical test of consistency between the matter and CMB dipoles
Time to Transition [Editor's Column]
No full textTime flies. It feels like yesterday that I took over the steering wheel of IEEE Industrial Electronics Magazine from Thilo Sauter for a three-year term, and now it is time for me pass it on to the next editor-in-chief (EIC). The IES president has appointed Eric Monmasson to fill this position for the coming three years and I am very happy with this choice. Eric was a tremendous support in his role as 'Society News' editor and associate editor during my time. He is very experienced and highly reputed. Intelligent Electrical Power Grid
Working with a women’s group in Titilaka, Peru to form a knitting association – an example of value based groupwork
Get PDFThis paper discusses in detail just one group meeting utilizing the social action group work approach for a group of women in Peru wishing to establish themselves as a knitting association. We describe the context of the work and the different elements and challenges when facilitating the workshop. The meeting was part of a community development process supported by an NGO Amantani and a local hotel – Hotel Titilaka. The facilitators of the session – Author 1 and Author 2 - are both European
The Quarries of Meroe, Sudan : Part 1 - Text
No full textAbout Part 1A team of international researchers present their research on all aspects of quarrying: history, geology, quarrying technique, graffiti in quarries, Meroitic and Greek inscriptions in quarries, as well as the petrography of Nubian sandstone. A final chapter deals with the challenges of surveying quarries in the desert. All articles have extensive Arabic summaries.MapA map in A0 format of the wider study area, with individual quarry locations marked. PDF - 25 MB.VideoThis two-part set is accompanied by five short educational and illustrative slideshows in English and Arabic about the authors’ work on the sandstone quarries around Meroe. The highlight is a 5-minute aerial and underground ‘fly-through’ video presenting quarry Q41, the largest and most impressive of the gallery quarries in the study area, available in 2D or 3D. All videos are available here: https://www.youtube.com/playlist?list=PL7-ic31cMSbvWosaClqx-qHJYtYWraVgB.AcknowledgementThis publication and the associated videos were made possible by NPRP grant 5-879-6-025 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the author(s).Other InformationEditors: Brigitte Cech, Thilo Rehren and Abdelrahman Ali MohamedLicense: https://creativecommons.org/licenses/by/4.0See book on publisher's website: https://doi.org/10.5339/uclq.2018.9789927118876</p
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