1,738 research outputs found

    Stellar orbits in cosmological galaxy simulations: the connection to formation history and line-of-sight kinematics

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    We analyze orbits of stars and dark matter out to three effective radii for 42 galaxies formed in cosmological zoom simulations. Box orbits always dominate at the centers and zz-tubes become important at larger radii. We connect the orbital structure to the formation histories and specific features (e.g. disk, counter-rotating core, minor axis rotation) in two-dimensional kinematic maps. Globally, fast rotating galaxies with significant recent in situ star formation are dominated by zz-tubes. Slow rotators with recent mergers have significant box orbit and xx-tube components. Rotation, quantified by the λR\lambda_R-parameter often originates from streaming motion of stars on zz-tubes but sometimes from figure rotation. The observed anti-correlation of h3h_3 and V0/σV_0 / \sigma in rotating galaxies can be connected to a dissipative formation history leading to high zz-tube fractions. For galaxies with recent mergers in situ formed stars, accreted stars and dark matter particles populate similar orbits. Dark matter particles have isotropic velocity dispersions. Accreted stars are typically radially biased (ÎČ≈0.2−0.4\beta \approx 0.2 - 0.4). In situ stars become tangentially biased (as low as ÎČ≈−1.0\beta \approx -1.0) if dissipation was relevant during the late assembly of the galaxy. We discuss the relevance of our analysis for integral field surveys and for constraining galaxy formation models.Comment: 21 pages, 19 figure

    Reconstructing the Ancient Route Network in Pergamon’s Surroundings

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    The surrounding landscape of ancient Pergamon is characterized by several mountain ranges, the Bakırçay Valley and River and the Aegean coastline. The accessibility of this region was vital for the city since it provided food and resources as well as trade, communication and military movements, all facilitated by a well-developed route network. Despite the importance of roads for the development and prosperity of the city, the ancient route network is still widely unexplored and archeological evidence of roads is extremely rare. This study therefore aims to reconstruct the ancient route network in the surroundings of Pergamon by combining historical and archeological sources with modern computer-aided least-cost path analyses, while also considering changes in the landscape that have occurred since antiquity. Based on these detailed results, conclusions may be drawn about the characteristics and functional diversity of the routes. Although the investigation of the route network in the surroundings of Pergamon cannot be considered complete, the results of this study already offer a valuable basis for further research, analyses, modeling and field work

    A monograph on the morphology of stigmarioid branches

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    Leichtes Spiel : Merry Play

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    https://digitalcommons.library.umaine.edu/mmb-ps/3182/thumbnail.jp

    The Flute Player : A Study Of The Trill

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    https://digitalcommons.library.umaine.edu/mmb-ps/1520/thumbnail.jp

    BaFe2As2/Fe bilayers with [001]-tilt grain boundary on MgO and SrTiO3 bicrystal substrates

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    Co-doped BaFe2As2 (Ba-122) can be realized on both MgO and SrTiO3 bicrystal substrates with [001]-tilt grain boundary by employing Fe buffer layers. However, an additional spinel (i.e. MgAl2O4) buffer between Fe and SrTiO3 is necessary since an epitaxial, smooth surface of Fe layer can not be grown on bare SrTiO3. Both types of bicrystal films show good crystalline quality.Comment: Accepted for the ISS2012 Proceedins, a special issue of Physics Procedi

    Der Froehliche Wanderer

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    https://digitalcommons.library.umaine.edu/mmb-ps/2076/thumbnail.jp

    Song Of Love

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    https://digitalcommons.library.umaine.edu/mmb-ps/3425/thumbnail.jp

    Reversible shift in the superconducting transition for La1.85Sr0.15CuO4 and BaFe1.8Co0.2As2 using piezoelectric substrates

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    The use of piezoelectric substrates enables a dynamic observation of strain dependent properties of functional materials. Based on studies with La1.85Sr0.15CuO4 we extended this approach to the iron arsenic superconductors represented by BaFe2-xCoxAs2 to investigate strain driven changes in detail. We demonstrate that epitaxial thin films can be prepared on (001)Pb(Mg1/3Nb2/3)0.72Ti0.28O3 substrates using pulsed laser deposition. The structural as well as the electric properties of the grown films were characterized in detail. A reversible shift of the superconducting transition of 0.44 K for La1.85Sr0.15CuO4 and 0.2 K for BaFe1.8Co0.2As2 was observed applying a biaxial strain of 0.022% and 0.017% respectively

    Untersuchungen zur diÀtetischen Normalisierung der Calciumhomöostase und zur in vitro-Insulinsekretion der Langerhans-Inseln bei PVDR 1-Schweinen

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    Verschiedene Studien deuten auf eine Beteiligung des Vitamin-D-Hormonsystems in der Entwicklung von Diabetes mellitus hin. Aufgrund eines Defekts in der 1,25(OH)2-Vitamin-D-Synthese stellt das PVDR 1-Schwein ein sehr gutes Modell zur Erforschung der Wirkung von 1,25(OH)2-Vitamin D auf das endokrine Pankreas dar. Die Evaluierung des direkten Einflusses von Vitamin D auf die Langerhans Inseln in vivo erfordert, dass in den Versuchstieren Vitamin D-unabhĂ€ngige normocalcĂ€mische Bedingungen herrschen, da HypocalcĂ€mie per se eine verminderte Funktion des endokrinen Pankreas mit sich bringt. Der Hauptteil dieser Arbeit bestand in den Bestrebungen, diese normocalcĂ€mischen Bedingungen dietĂ€tisch mit Lactose, Lactulose, Maltitol, Xylitol und Difruktosedianhydrid III (DFA III) zu erzeugen. Vor der Testung der Substanzen auf deren Vermögen den ionisierten Calciumspiegel im Blut zu erhöhen, wurden Toleranztests durchgefĂŒhrt, um einen negativen Effekt auf die Gesundheit der Versuchsschweine auszuschließen. Die Wirkungstests mit adulten Schweinen ergaben, dass NormocalcĂ€mie durch die ZufĂŒtterung von Lactose (35%), Lactulose (20%), Maltitol (30%), Xylitol (30%) oder DFA III (6%) in der ursprĂŒnglichen Substanz beim PVDR 1-Schwein nicht erreicht werden kann. Dennoch konnten wir zeigen, dass vor allem Xylitol und in abgeschwĂ€chter Form auch Lactulose eine tendenzielle Steigerung des ionisierten Calciumgehaltes im Vollblut von homozygoten Schweinen bewirkt. Nachdem in adulten Schweinen keine NormocalcĂ€mie mittels unterschiedlich angereichertem Futter erreicht werden konnte, sollte im zweiten Teil der Arbeit ĂŒberprĂŒft werden, ob mit Hilfe von supplementierten Milchaustauscherfutter (MAT) eine Normalisierung des Calciumhaushaltes bei PVDR 1-Ferkeln möglich ist. Bei heterozygoten Ferkeln hatte DFA III tendenziell einen positiven Effekt auf die Calcium-Konzentration im Blut. Bei homozygoten Ferkeln zeigte sich jedoch kein Effekt auf die Calcium-Konzentration im Blut. Deutliche Unterschiede in den Überlebensraten der Versuchsgruppen, nĂ€mlich 80% in der DFA III- und 25% in der Kontrollgruppe, lassen darauf schließen, dass DFA III eine gĂŒnstige Wirkung auf die Entwicklung der Rachitis bei PVDR 1-Ferkeln hat. ZusĂ€tzliche in vitro-Untersuchungen mit Langerhans-Inseln von Wildtyp- und PVDR 1-Ferkeln, durchgefĂŒhrt um die Wirkung von 1,25(OH)2-Vitamin D auf die Insulinsekretion zu ĂŒberprĂŒfen, ergaben, dass Vitamin D-stimulierte Wildtyp-Inseln höhere Insulinsekretionen aufwiesen. Die Insulinsekretionen der Pankreas-Inseln von PVDR 1-Tieren, die signifikant niedriger waren als die der Wildtyp-Ferkel, konnten jedoch durch 1,25(OH)2-Vitamin D nicht gesteigert werden. Aufbauend auf diese Studie könnten Folgeversuche mit anderen Substanzen und höheren Tierzahlen diesem Tiermodell eine höhere Aussagekraft verleihen.Several studies indicate an association between the vitamin D hormone system and diabetes mellitus. In this work we employed the PVDR 1 pig, which is characterized by a defect in 1,25(OH)2 vitamin D synthesis, to further investigate the roll of vitamin D for the endocrine pancreas. To evaluate direct influences of vitamin D it is necessary to establish normocalcemic conditions. Therefore, the main focus of this project was to generate normocalcemia in PVDR 1 homozygous pigs by testing different rescue diets. Within this study normal food was supplemented with lactose, lactulose, maltitol, xylitol and difructoseanhydride (DFA III). The tolerance to these substances was evaluated in preliminary tests. In the final experiments, the diets offered to adult PVDR 1 pigs were supplemented with 35% lactose, 20% lactulose, 30% maltitol, 30% xylitol or 6% DFA III, respectively. Unfortunately, none of these diets was able to increase ionized calcium levels. However, xylitol and to a lesser extent lactulose induced slight increases in calcium values. Aim of the second part of the study was to establish normocalcemia in piglets by feeding milk replacer supplemented with xylitol or DFA III. Here, we could show that in piglets heterozygous for PVDR 1, i.e., harboring a functional vitamin D hormone system, DFA III as a dietary supplement seemed to exert a positive effect on the calcium balance. No significant effect on blood calcium concentration could be detected in homozygous piglets. Additionally, the survival rates of the DFA III treated homozygous group were clearly elevated to 80% as compared with the control group (25%), suggesting an positive influence of DFA III on the manifestation of the PVDR 1 disease. Further, we examined the ability of 1,25(OH)2 vitamin D to stimulate insulin secretion in in vitro experiments. Although insulin secretion of islets from homozygous PVDR 1 pigs was significantly reduced compared to wildtype, vitamin D was not able to normalize the reduced insulin secretory capacity in PVDR 1 islets. In contrast, vitamin D increased insulin secretion in wildtype islets. Further studies with higher animal numbers and additional dietary supplements might increase the utility of the PVDR 1 pig model
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