180 research outputs found

    Photons from strange-quark annihilation in a quark-gluon plasma

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    We compute the energy spectrum of photons which originate from the quark-annihilation process ss¯→γg in quark-gluon plasma. The spectrum peaks at an energy Eγmax∼2ms∼400 MeV in the rest frame of the plasma. We expect one photon from the above process in the energy range of 2ms±0.25ms per hundred quark-gluon plasmas of a size R=3 fm and a lifetime τ=6 fm/c formed in nuclear collisions

    Real-time Halfway Domain Reconstruction of Motion and Geometry

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    We present a novel approach for real-time joint reconstruction of 3D scene motion and geometry from binocular stereo videos. Our approach is based on a novel variational halfway-domain scene flow formulation, which allows us to obtain highly accurate spatiotemporal reconstructions of shape and motion. We solve the underlying optimization problem at real-time frame rates using a novel data-parallel robust non-linear optimization strategy. Fast convergence and large displacement flows are achieved by employing a novel hierarchy that stores delta flows between hierarchy levels. High performance is obtained by the introduction of a coarser warp grid that decouples the number of unknowns from the input resolution of the images. We demonstrate our approach in a live setup that is based on two commodity webcams, as well as on publicly available video data. Our extensive experiments and evaluations show that our approach produces high-quality dense reconstructions of 3D geometry and scene flow at real-time frame rates, and compares favorably to the state of the art

    Covariant Hamiltonian Field Theory

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    A consistent, local coordinate formulation of covariant Hamiltonian field theory is presented. Whereas the covariant canonical field equations are equivalent to the Euler-Lagrange field equations, the covariant canonical transformation theory offers more general means for defining mappings that preserve the form of the field equations than the usual Lagrangian description. It is proved that Poisson brackets, Lagrange brackets, and canonical 2-forms exist that are invariant under canonical transformations of the fields. The technique to derive transformation rules for the fields from generating functions is demonstrated by means of various examples. In particular, it is shown that the infinitesimal canonical transformation furnishes the most general form of Noether's theorem. We furthermore specify the generating function of an infinitesimal space-time step that conforms to the field equations.Comment: 93 pages, no figure

    Sites of Failure in Breast Cancer Patients with Extracapsular Invasion of Axillary Lymph Node Metastases: No Need for Axillary Irradiation?!

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    Background and Purpose:: Extracapsular spread (ECS) is frequent, but the specific sites of relapse are seldom given in the literature. In this study it was evaluated, if ECS might be an indicator for axillary irradiation. Patients and Methods:: After a retrospective review of pathology reports, the information about ECS was available in 254 lymph node-positive patients: ECS was absent in 34% (ECS-negative; n = 87) and present in 66% (ECS-positive; n = 167). All patients were irradiated locally, 78 patients got periclavicular and 74 axillary irradiation (median total dose: 50.4 Gy). 240/254 patients (94.5%) received systemic treatment/s. Mean follow-up was 46 months. Results:: The regional relapse rate was 4.6% without ECS versus 9.6% with ECS. The 5-year axillary relapse-free survival was 100% in ECS-negative and 90% in ECS-positive patients (p = 0.01), whereas corresponding values for periclavicular relapse-free survival (with ECS: 91% ± 4%; without ECS: 94% ± 3%; p = 0.77) and local relapse-free survival (with ECS: 86% ± 4%; without ECS: 91% ± 3%; p = 0.69) were not significantly different. χ2-tests revealed a high correlation of ECS with T-stage, number of positive lymph nodes and progesterone receptor status, comparisons with estrogen receptor, grade, or age were not significant. In multivariate analysis number of positive lymph nodes was solely significant for regional failure. Dividing the patients into those with one to three and those with four or more positive lymph nodes, ECS lost its significance for axillary failure. Conclusion:: ECS was accompanied by an enhanced axillary failure rate in univariate analysis, which was no longer true after adjusting for the number of positive lymph node

    Surface Effects in Magnetic Microtraps

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    We have investigated Bose-Einstein condensates and ultra cold atoms in the vicinity of a surface of a magnetic microtrap. The atoms are prepared along copper conductors at distances to the surface between 300 um and 20 um. In this range, the lifetime decreases from 20 s to 0.7 s showing a linear dependence on the distance to the surface. The atoms manifest a weak thermal coupling to the surface, with measured heating rates remaining below 500 nK/s. In addition, we observe a periodic fragmentation of the condensate and thermal clouds when the surface is approached.Comment: 4 pages, 4 figures; v2: corrected references; v3: final versio

    Real-time Halfway Domain Reconstruction of Motion and Geometry

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    We present a novel approach for real-time joint reconstruction of 3D scene motion and geometry from binocular stereo videos. Our approach is based on a novel variational halfway-domain scene flow formulation, which allows us to obtain highly accurate spatiotemporal reconstructions of shape and motion. We solve the underlying optimization problem at real-time frame rates using a novel data-parallel robust non-linear optimization strategy. Fast convergence and large displacement flows are achieved by employing a novel hierarchy that stores delta flows between hierarchy levels. High performance is obtained by the introduction of a coarser warp grid that decouples the number of unknowns from the input resolution of the images. We demonstrate our approach in a live setup that is based on two commodity webcams, as well as on publicly available video data. Our extensive experiments and evaluations show that our approach produces high-quality dense reconstructions of 3D geometry and scene flow at real-time frame rates, and compares favorably to the state of the art.Comment: Proc. of the International Conference on 3D Vision 2016 (3DV 2016

    Synthesis, biological evaluation, and SAR studies of 14β-phenylacetyl substituted 17-cyclopropylmethyl-7, 8-dihydronoroxymorphinones derivatives : Ligands with mixed NOP and opioid receptor profile

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    © 2018 Kumar, Polgar, Cami-Kobeci, Thomas, Khroyan, Toll and Husbands.A series of 14β-acyl substituted 17-cyclopropylmethyl-7,8-dihydronoroxymorphinone compounds has been synthesized and evaluated for affinity and efficacy for mu (MOP), kappa (KOP), and delta (DOP) opioid receptors and nociceptin/orphanin FQ peptide (NOP) receptors. The majority of the new ligands displayed high binding affinities for the three opioid receptors, and moderate affinity for NOP receptors. The affinities for NOP receptors are of particular interest as most classical opioid ligands do not bind to NOP receptors. The predominant activity in the [35S]GTPγS assay was partial agonism at each receptor. The results are consistent with our prediction that an appropriate 14β side chain would access a binding site within the NOP receptor and result in substantially higher affinity than displayed by the parent compound naltrexone. Molecular modeling studies, utilizing the recently reported structure of the NOP receptor, are also consistent with this interpretation.Peer reviewedFinal Published versio

    Perspectives of Ultra Cold Atoms Trapped in Magnetic Micro Potentials

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    Recent work on magnetic micro traps for ultracold atoms is briefly reviewed. The basic principles of operation are described together with the loading methods and some of the realized trap geometries. Experiments are discussed that study the interaction between atoms and the surface of micro traps as well as the dynamics of ultracold gases in wave guides are discussed. The results allow for an outlook towards future directions of research

    Determination of the domain of the admissible matrix elements in the four-dimensional PT-symmetric anharmonic model

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    Many manifestly non-Hermitian Hamiltonians (typically, PT-symmetric complex anharmonic oscillators) possess a strictly real, "physical" bound-state spectrum. This means that they are (quasi-)Hermitian with respect to a suitable non-standard metric. The domain D of the existence of this metric is studied here for a nontrivial though still non-numerical four-parametric "benchmark" matrix model.Comment: 18 pages, 2 figure

    A return to observability near exceptional points in a schematic PT-symmetric model

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    Many indefinite-metric (often called pseudo-Hermitian or PT-symmetric) quantum models H prove "physical" (i.e., Hermitian with respect to an innovated, ad hoc scalar product) inside a characteristic domain of parameters D. This means that the energies get complex (= unobservable) beyond the boundary (= Kato's "exceptional points", EPs). In a solvable example we detect an enlargement of D caused by the emergence of a new degree of freedom. We conjecture that such a beneficial mechanism of a return to the real spectrum near EPs may be generic and largely model-independent.Comment: 14 pp., 1 fi
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