458 research outputs found

    Vom samtigen Pastell zum leuchtenden Glas: Ida Kerkovius` Entwürfe für Glasfenster in Stuttgart

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    In ihrem umfangreichen Gesamtwerk verwendet Ida Kerkovius die unterschiedlichsten künstlerischen Techniken: vom spontanen Aquarell zum ambitionierten Ölbild, von der flüchtigen Bleistiftskizze zu der von ihr besonders geschätzten Pastellkreide. Die Künstlerin war neuen Anregungen gegenüber zumeist aufgeschlossen. Sie hatte beispielsweise Anfang der 1920er Jahre am Bauhaus auch die Webtechnik erlernt. So konnte sie in den schwierigen Kriegsjahren 1940–1945 durch selbst hergestellte Teppiche, Decken und Kissenbezüge ihre finanzielle Situation verbessern. Die Anzahl der von Ida Kerkovius gestalteten Glasfenster ist im Vergleich zu ihrem übrigen Werk zwar gering, ihre Auseinandersetzung mit dieser Technik eröffnet jedoch interessante Gesichtspunkte

    A cryptic record of Burgess Shale-type diversity from the early Cambrian of Baltica

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    Exceptionally preserved ‘Burgess Shale-type’ fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non-biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerstätten. Here we report a diverse assemblage of small carbonaceous fossils (SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale-type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as ‘protoconodonts’, denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high-latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda gen. et sp. nov. (a priapulid), Baltichaeta jormunganda gen. et sp. nov. (an annelid) and Baltinema rana gen. et sp. nov. (a filamentous problematicum)

    Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns. I. Evolution of structure and kinematics

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    We report the results of long-term reverberation mapping (RM) campaigns of the nearby active galactic nuclei (AGN) NGC 4151, spanning from 1994 to 2022, based on archived observations of the FAST Spectrograph Publicly Archived Programs and our new observations with the 2.3m telescope at the Wyoming Infrared Observatory. We reduce and calibrate all the spectra in a consistent way, and derive light curves of the broad Hβ\beta line and 5100\,{\AA} continuum. Continuum light curves are also constructed using public archival photometric data to increase sampling cadences. We subtract the host galaxy contamination using {\it HST} imaging to correct fluxes of the calibrated light curves. Utilizing the long-term archival photometric data, we complete the absolute flux-calibration of the AGN continuum. We find that the Hβ\beta time delays are correlated with the 5100\,{\AA} luminosities as τHβL51000.46±0.16\tau_{\rm H\beta}\propto L_{5100}^{0.46\pm0.16}. This is remarkably consistent with Bentz et al. (2013)'s global size-luminosity relationship of AGNs. Moreover, the data sets for five of the seasons allow us to obtain the velocity-resolved delays of the Hβ\beta line, showing diverse structures (outflows, inflows and disks). Combining our results with previous independent measurements, we find the measured dynamics of the Hβ\beta broad-line region (BLR) are possibly related to the long-term trend of the luminosity. There is also a possible additional \sim1.86 years time lag between the variation in BLR radius and luminosity. These results suggest that dynamical changes in the BLR may be driven by the effects of radiation pressure.Comment: Accepted for publication in MNRAS; comments welcome

    The apparatus composition and architecture of Erismodus quadridactylus and the implications for element homology in prioniodinin conodonts

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    The apparatus composition and architecture of prioniodinin conodonts is poorly understood, largely because few prioniodinin taxa are represented by articulated oral feeding apparatuses (natural assemblages) in the fossil record, but also due to the highly variable gradational morphology of their constituent elements that makes apparatus reconstruction problematic. We describe here a natural assemblage of Erismodus quadridactylus (Stauffer), a prioniodinin, from the Sandbian (Late Ordovician) of North Dakota, USA. The assemblage demonstrates that the apparatus architecture of Erismodus is similar to those of late Palaeozoic prioniodinins namely, Kladognathus Rexroad and Hibbardella Bassler, but also has similarities with ozarkodinin apparatuses. In addition, there is evidence to suggest that E. quadridactylus shares topological similarities to balognathid architecture, with respect to the position of its inferred P elements. The apparatus composition and architecture presented here indicate that, at least with respect to the M–S array, an ‘ozarkodinin‐type’ bauplan is probably more widely representative across prioniodontids. The assemblage demonstrates that element morphotypes traditionally considered to lie within the S array are M elements, whereas others traditionally interpreted as P elements are found in the S array. These observations are used as a basis for refining concepts of element homology among prioniodinin conodonts and their closest relatives

    Monitoring AGNs with Hβ\beta Asymmetry. IV. First Reverberation Mapping Results of 14 AGNs

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    We report first-time reverberation mapping results for 14 AGNs from the ongoing Monitoring AGNs with Hβ\beta Asymmetry campaign (MAHA). These results utilize optical spectra obtained with the Long Slit Spectrograph on the Wyoming Infrared 2.3m Telescope between 2017 November-2023 May. MAHA combines long-duration monitoring with high cadence. We report results from multiple observing seasons for 9 of the 14 objects. These results include Hβ\beta time lags, supermassive black hole masses, and velocity-resolved time lags. The velocity-resolved lags allow us to investigate the kinematics of the broad-line region.Comment: 35 pages, 19 figures, accepted for publication in ApJ Supplemen

    A cryptic record of Burgess Shale-type diversity from the early Cambrian of Baltica

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    Palaeontology published by John Wiley & Sons Ltd on behalf of The Palaeontological Association.Exceptionally preserved ‘Burgess Shale-type’ fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non-biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerstätten. Here we report a diverse assemblage of small carbonaceous fossils (SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale-type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as ‘protoconodonts’, denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high-latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda\textit{Baltiscalida njorda} gen. et sp. nov. (a priapulid), Baltichaeta jormunganda\textit{Baltichaeta jormunganda} gen. et sp. nov. (an annelid) and Baltinema rana\textit{Baltinema rana} gen. et sp. nov. (a filamentous problematicum).We acknowledge the support of Churchill College, Cambridge (BJS) and Clare Hall College, Cambridge (RG). This research was funded by the Natural Environmental Research Council, UK, grant NE/K005251/1 (BJS, THPH, RG, NJB)
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