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  • 1
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    German Medical Science GMS Publishing House; Düsseldorf
    In:  Prävention zwischen Evidenz und Eminenz; 15. Jahrestagung des Deutschen Netzwerks Evidenzbasierte Medizin; 20140313-20140315; Halle; DOC14ebmC2d /20140310/
    Publication Date: 2014-03-11
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
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  • 2
    Publication Date: 2018-09-15
    Description: Topological insulators are materials that have a gapped bulk energy spectrum but contain protected in-gap states appearing at their surface. These states exhibit remarkable properties such as unidirectional propagation and robustness to noise that offer an opportunity to improve the performance and scalability of quantum technologies. For quantum applications, it is essential that the topological states are indistinguishable. We report high-visibility quantum interference of single-photon topological states in an integrated photonic circuit. Two topological boundary states, initially at opposite edges of a coupled waveguide array, are brought into proximity, where they interfere and undergo a beamsplitter operation. We observe Hong-Ou-Mandel interference with 93.1 ± 2.8% visibility, a hallmark nonclassical effect that is at the heart of linear optics–based quantum computation. Our work shows that it is feasible to generate and control highly indistinguishable single-photon topological states, opening pathways to enhanced photonic quantum technology with topological properties, and to study quantum effects in topological materials.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 3
    Publication Date: 2018-02-24
    Description: Many puzzling properties of high–critical temperature ( T c ) superconducting (HTSC) copper oxides have deep roots in the nature of the antinodal quasiparticles, the elementary excitations with wave vector parallel to the Cu–O bonds. These electronic states are most affected by the onset of antiferromagnetic correlations and charge instabilities, and they host the maximum of the anisotropic superconducting gap and pseudogap. We use time-resolved extreme-ultraviolet photoemission with proper photon energy (18 eV) and time resolution (50 fs) to disclose the ultrafast dynamics of the antinodal states in a prototypical HTSC cuprate. After photoinducing a nonthermal charge redistribution within the Cu and O orbitals, we reveal a dramatic momentum-space differentiation of the transient electron dynamics. Whereas the nodal quasiparticle distribution is heated up as in a conventional metal, new quasiparticle states transiently emerge at the antinodes, similarly to what is expected for a photoexcited Mott insulator, where the frozen charges can be released by an impulsive excitation. This transient antinodal metallicity is mapped into the dynamics of the O-2p bands, thus directly demonstrating the intertwining between the low- and high-energy scales that is typical of correlated materials. Our results suggest that the correlation-driven freezing of the electrons moving along the Cu–O bonds, analogous to the Mott localization mechanism, constitutes the starting point for any model of high- T c superconductivity and other exotic phases of HTSC cuprates.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 4
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The γ-radiation-induced free-radical copolymerization of ethylene and CO has been investigated over a wide range of pressure, initial gas composition, radiation intensity, and temperature. At 20°C., concentrations of CO up to 1% retard the polymerization of ethylene. Above this concentration the rate reaches a maximum between 27.5 and 39.2% CO and then decreases. The copolymer composition increases only from 40 to 50% CO when the gas mixture is varied from 5 to 90% CO. A relatively constant reactivity ratio is obtained at 20°C., indicating that CO adds 23.6 times as fast as an ethylene monomer to an ethylene free-radical chain end. For a 50% CO gas mixture, the above value of 23.6 and the copolymerization rate decrease with increasing temperature to 200°C. The kinetic data indicate a temperature-dependent depropagation reaction. Infrared examination of copolymers indicates a polyketone structure containing —CH2—CH2— and —CO— units. The crystalline melting point increases rapidly from 111 to 242°C., as the CO concentration in the copolymer increases from 27 to 50%. Molecular weight of copolymer formed at 20°C. increased with increasing CO, indicating M̄n values 〉20,000. Increasing reaction temperature results in decreasing molecular weight. Onset of decomposition for a 50% CO copolymer was measured at ≈250°C.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1437-1596
    Keywords: Intraventricular haemorrhage ; Head injury ; Traumatic subarachnoid haemorrhage ; Intraventrikuläre Blutung ; Kopftrauma ; Traumatische Subarachnoidalblutung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Der Fall eines 26 Jahre alten Mannes wird beschrieben, welcher nach einer Episode von Traumen eine tödliche intraventrikuläre Hirnblutung erlitt. Bei der Obduktion wurde nach dem ersten Eindruck eine traumatische Subarachnoidalblutung vermutet, und die anfängliche Untersuchung war daher auf die Strukturen des Halses und auf die Vertebralarterien gerichtet, jedoch mit negativen Resultaten. Die Sektion des fixierten Gehirns zeigte eine massive intraventrikuläre Blutung mit sekundärer Beteiligung des Subarachnoidalraums und Ausbreitung in das Hirnparenchym. Keine Blutungsquellen oder natürliche Erkrankungen der Hirngefäße konnten gefunden werden. Die praktischen Aspekte der Diagnose und der vorsichtige Ansatz, welcher notwendig ist, um Subarachnoidalblutungen zu interpretieren, werden betont. Die Bedeutung der intraventrikulären Blutung nach Trauma ist mit der Einführung der Computertomographie offensichtlicher geworden. Die Implikationen dieses und ähnlicher Fälle werden bedacht.
    Notes: Summary A case of a 26-year-old man who suffered a fatal intraventricular cerebral haemorrhage following an episode of trauma is described. The initial appearance at necropsy suggested a traumatic subarachnoid haemorrhage and initial investigation was directed towards the anterior neck structures and the vertebral arteries with negative results. Dissection of the fixed brain showed a massive intraventricular bleed with secondary involvement of the subarachnoid space and dissection into the cerebral parenchyma. No bleeding points or natural disease of the cerebral vessels could be identified. The practical aspects of diagnosis and the cautious approach necessary in interpreting subarachnoid bleeding is emphasised. The significance of intraventricular haemorrhage following trauma has become more apparent with the advent of computed tomographic scanning. The implications for this and similar cases are considered.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-8889
    Keywords: associative learning ; grasshopper ; palpation ; plant surface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The behavioral responses of final-instar nymphs of Schistocerca americanato a variety of acceptable and unacceptable plants were recorded. Palpation occurred on all plants and the palps are involved in both acceptance and rejection. On most unacceptable plants, rejection was at first dependent on biting the leaf, but subsequently on Lantana, Machaeranthera, Moms,and Physalis,rejection often occurred after palpation of the surface alone. This is consistent with the suggestion that associative learning occurs. This response did not wane even when the insects had been without food for over 2 h. There was also some evidence of an innate response to the surface characteristics of Physalis.The features of the surfaces that produced these responses were not determined.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1572-8889
    Keywords: development ; food aversion learning ; grasshopper ; habituation ; plant acceptability ; polyphagy ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The feeding behavior of final-instar nymphs ofSchistocerca americana was observed when they first encountered plants that ranged in acceptability from being eaten in large amounts to not being eaten at all. Growth and survival on the same plants through the last stadium were also studied and the results combined as a suitability index to facilitate comparison with the behavior. Although the plants that were eaten most gave the highest suitability index and those that were not eaten permitted no survival, there was no simple relationship between the amounts eaten and the suitability for growth and survival. The possibility that the insects might become habituated to plants that were initially unacceptable was investigated, but no habituation was found over a 3-day period. It is suggested that food intake is largely determined by the presence of deterrent compounds in the less acceptable foods and that nutritional differences between the plants are likely to have been of minor importance. The behavior on some foods suggests that food aversion learning may be involved. It is concluded that the variability of the insects' behavior makes it impossible to predict the suitability of a plant from their immediate behavioral responses. In the field, insects may sometimes reject foods that would be suitable for survival and development, and feed on plants that are nutritionally deficient or even toxic.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1530-0358
    Keywords: Gallbladder ; Carcinoma ; Ulcerative colitis ; Primary sclerosing cholangitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The authors present the cases of two patients with carcinoma of the gallbladder complicating chronic ulcerative colitis. Both patients had concomitant primary sclerosing cholangitis. Twelve such cases of gallbladder carcinoma have been reported in the literature. The presence of primary sclerosing cholangitis in patients with ulcerative colitis is associated with malignancy of the extrahepatic biliary tree. It is suggested that, if colectomy is necessary, the liver should be biopsied and a cholecystectomy performed if the gallbladder is deemed abnormal.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Alle Hauptnerven des Mund- und Rachennervensystems wurden kontrolliert reseziert. Erst wenn die rückwärtigen Rachennerven zerschnitten werden, nehmen die Insekten wesentlich mehr Nahrung zu sich. Solche Insekten versuchen längere Zeit zu fressen. Wenn sich während des Fressens der Vorderdarm füllt, wird keine Nahrung an den Mitteldarm weitergegeben und sein Vorderende ist der letzte Teil, der sich vollständig ausdehnt. Nach Durchtrennung der rückwärtigen Rachennerven sind alle Teile des Vorderdarms offen-sichtlich mehr gedehnt. Eine solche erhöhte Nahrungsaufnahme tritt aber nicht ein, wenn die Nahrung relativ ungünstig ist. Das Abbinden des Kropfes verursacht beim nachträglichen Fressen keine übermäßige Ausdehnung des Vorderteiles. Die Nahrungsaufnahme hat keinen Unterschied im Körpervolumen zur Folge und das Durchtrennen des ventralen Nervenstranges bleibt ohne Einfluß auf die nachträglich aufgenommenen Nahrungsmengen. Das vergrößerte Darmvolumen wird durch Kollaps des Luftsackes kompensiert.
    Notes: Abstract During the course of a meal by insects with an empty gut, food is held in the foregut and the midgut remains empty. The last part of the foregut to fill is the extreme anterior end of the crop, and stretch receptors in this region control the amount eaten. Cutting the posterior pharyngeal nerves isolates these receptors from the frontal garglion and results in hyperphagia pharyngeal nerves isolates these receptors from the frontal garglion and results in hyperphagia during one meal. On unfavourable food, when smaller amounts are eaten, distension of the foregut is not involved in regulating meal size. Feedback from receptors in the body wall is not important in regulating meal size; most of the increase in gut volume resulting from feeding is taken up by the collapse of the air sacs so that there is little or no change in the body volume.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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