6,673 research outputs found

    Active clearance control system for a turbomachine

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    An axial compressor is provided with a cooling air manifold surrounding a portion of the shroud, and means for bleeding air from the compressor to the manifold for selectively flowing it in a modulating manner axially along the outer side of the stator/shroud to cool and shrink it during steady state operating conditions so as to obtain minimum shroud/rotor clearance conditions. Provision is also made to selectively divert the flow of cooling air from the manifold during transient periods of operation so as to alter the thermal growth or shrink rate of the stator/shroud and result in adequate clearance with the compressor rotor

    Strahlenpharmakologische untersuchungen mit neutronen an eisenhaltigen praparaten im Siemens unterrichtsreaktor SUR 100

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    Die stark eisenhaltigen Praparate Ferrlecit, Kobaltjerrlecit, Ferrojolsan, Ferrojolcamma und Irradian wurden im Siemens Unterrichtsreaktor SUR 100 des Instituts fur Kernenergetikder Universitat Struttgart und der Technischen Universitat, Berlin mit einem NeutronenfluB von ca. 5.l06n/cm2 sec bestrahlt. Es ollte dabei untersucht werden, wie stark eisenhaltige Praparate mit diesem Reaktor aktiviert werden konnen. Es wird festgestellt, daB Eisen praktisch kaum aktiviert wird. Die Ergebnisse zeigen, daB nur das Kobattjerrlecit und das Irradian starker durch Neutrosen aktiviert werden. Die hohere Aktivitat des Kobaltjerrlecit wird auf die darin enthaltenen Elemente Mangan, Kupfer und Kobalt zuruckgefuhrt, die mit thermischen Neutronen gut aktivierbar sind. Die hohere Aktivitat des Irradian geht hauptsachlich auf &#946;-Zerfalle zuruck. Das Phosphorisotop P-32 tragt einen gro&#946;en Anteil dazu bei. De r&#946;-Untergrund des Irradian bei hohen Energien, der mit einer kleinen Halbwertszeitabklingt, ist durch keines der angefuhrten Elemente im Irradian erklarbar. Der Mn-56Peak im Spektrum ist gut erkennbar, durch den &#946;-Untergrund wird er aber zu einer hoheren Energie hin verschoben.</p

    Extended Poincar\'e supersymmetry in three dimensions and supersymmetric anyons

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    We classify the unitary representations of the extended Poincar\'e supergroups in three dimensions. Irreducible unitary representations of any spin can appear, which correspond to supersymmetric anyons. Our results also show that all irreducible unitary representations necessarily have physical momenta. This is in sharp contrast to the ordinary Poincar\'e group in three dimensions, that admits in addition irreducible unitary representations with non-physical momenta, which are discarded on physical grounds.Comment: 7 pages; commentaries added in Sect. IV A and in Conclusion; added reference

    Optimised patient information materials and recruitment to a study of behavioural activation in older adults : an embedded study within a trial [version 1; peer review: awaiting peer review]

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    YesPrinted participant information about randomised controlled trials is often long, technical and difficult to navigate. Improving information materials is possible through optimisation and user-testing, and may impact on participant understanding and rates of recruitment. Methods: A study within a trial (SWAT) was undertaken within the CASPER trial. Potential CASPER participants were randomised to receive either the standard trial information or revised information that had been optimised through information design and user testing. Results: A total of 11,531 patients were randomised in the SWAT. Rates of recruitment to the CASPER trial were 2.0% in the optimised information group and 1.9% in the standard information group (odds ratio 1.027; 95% CI 0.79 to 1.33; p=0.202). Conclusions: Participant information that had been optimised through information design and user testing did not result in any change to rate of recruitment to the host trial. Registration: ISRCTN ID ISRCTN02202951; registered on 3 June 2009.UK National Institute of Health Research Health Technology Assessment Programme (project number 08/19/04)This article is included in the Studies Within A Trial (SWAT) collection (https://f1000research.com/collections/swat

    Lessons from LIMK1 enzymology and their impact on inhibitor design

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    LIM domain kinase 1 (LIMK1) is a key regulator of actin dynamics. It is thereby a potential therapeutic target for the prevention of fragile X syndrome and amyotrophic lateral sclerosis. Herein, we use X-ray crystallography and activity assays to describe how LIMK1 accomplishes substrate specificity, to suggest a unique ‘rock-and-poke’ mechanism of catalysis and to explore the regulation of the kinase by activation loop phosphorylation. Based on these findings, a differential scanning fluorimetry assay and a RapidFire mass spectrometry activity assay were established, leading to the discovery and confirmation of a set of small-molecule LIMK1 inhibitors. Interestingly, several of the inhibitors were inactive towards the closely related isoform LIMK2. Finally, crystal structures of the LIMK1 kinase domain in complex with inhibitors (PF-477736 and staurosporine, respectively) are presented, providing insights into LIMK1 plasticity upon inhibitor binding

    The Cold and Hot Gas Content of Fine-Structure E and S0 Galaxies

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    We investigate trends of the cold and hot gas content of early-type galaxies with the presence of optical morphological peculiarities, as measured by the fine-structure index (Sigma). HI mapping observations from the literature are used to track the cold-gas content, and archival ROSAT PSPC data are used to quantify the hot-gas content. We find that E and S0 galaxies with a high incidence of optical peculiarities are exclusively X-ray underluminous and, therefore, deficient in hot gas. In contrast, more relaxed galaxies with little or no signs of optical peculiarities span a wide range of X-ray luminosities. That is, the X-ray excess anticorrelates with Sigma. There appears to be no similar trend of cold-gas content with either fine-structure index or X-ray content. The fact that only apparently relaxed E and S0 galaxies are strong X-ray emitters is consistent with the hypothesis that after strong disturbances such as a merger hot-gas halos build up over a time scale of several gigayears. This is consistent with the expected mass loss from stars.Comment: 12 pages, latex, 5 figures. Accepted for publication in A

    The hot and cold interstellar matter of early type galaxies and their radio emission

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    Over the last few years, the knowledge of the interstellar matter (ISM) of early type galaxies has increased dramatically. Many early type galaxies are now known to have ISM in three different phases: cold (neutral hydrogen (HI), dust and molecular material), warm (ionized) and hot (S-ray emitting) gas. Early type galaxies have smaller masses of cold ISM (10 to the 7th power - 10 to the 8th power solar mass; Jura et al. 1987) than later type spiral galaxies, while they have far more hot gas (10 to the 9th power - 10 to the tenth power solar mass; Forman et al. 1985, Canizares et al. 1987). In order to understand the relationship between the different phases of the ISM and the role of the ISM in fueling radio continuum sources and star formation, researchers compared observational data from a wide range of wavelengths

    Influence of Complex Exciton-Phonon Coupling on Optical Absorption and Energy Transfer of Quantum Aggregates

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    We present a theory that efficiently describes the quantum dynamics of an electronic excitation that is coupled to a continuous, highly structured phonon environment. Based on a stochastic approach to non-Markovian open quantum systems, we develop a dynamical framework that allows us to handle realistic systems where a fully quantum treatment is desired yet the usual approximation schemes fail. The capability of the method is demonstrated by calculating spectra and energy transfer dynamics of mesoscopic molecular aggregates, elucidating the transition from fully coherent to incoherent transfer
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