10,151 research outputs found

    Dynamical coupled-channel model of kaon-hyperon interactions

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    The pi N --> KY and KY --> KY reactions are studied using a dynamical coupled-channel model of meson-baryon interactions at energies where the baryon resonances are strongly excited. The channels included are: pi N, K \Lambda, and K\Sigma. The resonances considered are: N^* [S_{11}(1650), P_{11}(1710), P_{13}(1720),D_{13}(1700)]; \Delta^* [S_{31}(1900), P_{31}(1910), P_{33}(1920)]; \Lambda ^* [S_{01}(1670), P_{01}(1810)] \Sigma^* [P_{11}(1660), D_{13}(1670)]; and K^*(892). The basic non-resonant \pi N --> KY and KY --> KY transition potentials are derived from effective Lagrangians using a unitary transformation method. The dynamical coupled-channel equations are simplified by parametrizing the pi N -->pi N amplitudes in terms of empirical pi N partial-wave amplitudes and a phenomenological off-shell function. Two models have been constructed. Model A is built by fixing all coupling constants and resonance parameters using SU(3) symmetry, the Particle Data Group values, and results from a constituent quark model. Model B is obtained by allowing most of the parameters to vary around the values of model A in fitting the data. Good fits to the available data for pi^- p to K^0 \Lambda, K^0 \Sigma^0 have been achieved. The investigated kinematics region in the center-of-mass frame goes from threshold to 2.5 GeV. The constructed models can be imbedded into associated dynamical coupled-channel studies of kaon photo- and electro-production reactions.Comment: 35 pages, 11 Figure

    String Creation, D-branes and Effective Field Theory

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    This paper addresses several unsettled issues associated with string creation in systems of orthogonal Dp-D(8-p) branes. The interaction between the branes can be understood either from the closed string or open string picture. In the closed string picture it has been noted that the DBI action fails to capture an extra RR exchange between the branes. We demonstrate how this problem persists upon lifting to M-theory. These D-brane systems are analysed in the closed string picture by using gauge-fixed boundary states in a non-standard lightcone gauge, in which RR exchange can be analysed precisely. The missing piece in the DBI action also manifests itself in the open string picture as a mismatch between the Coleman-Weinberg potential obtained from the effective field theory and the corresponding open string calculation. We show that this difference can be reconciled by taking into account the superghosts in the (0+1)effective theory of the chiral fermion, that arises from gauge fixing the spontaneously broken world-line local supersymmetries.Comment: 33 page

    On Neutrino Masses and Family Replication

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    The old issue of why there are more than one family of quarks and leptons is reinvestigated with an eye towards the use of anomaly as a tool for constraining the number of families. It is found that, by assuming the existence of right-handed neutrinos (which would imply that neutrinos will have a mass) and a new chiral SU(2) gauge theory, strong constraints on the number of families can be obtained. In addition, a model, based on that extra SU(2), is constructed where it is natural to have one "very heavy" fourth neutrino and three almost degenerate light neutrinos whose masses are all of the Dirac type.Comment: RevTex, 12 pages with 1 figure, minor changes to the text and added acknowledgment

    Superstring-Inspired E_6 Unification, Shadow Theta-Particles and Cosmology

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    We construct a new cosmological model considering the superstring-inspired E_6 unification in the 4-dimensional space at the early stage of the Universe. We develop a concept of parallel existence in Nature of the ordinary and shadow worlds with different cosmological evolutions.Comment: 7 page

    Smart TV face monitoring for children privacy

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    © 2018 Taiwan Academic Network Management Committee. All Rights Reserved. Many of the modern Television (TV) sets and digital TV set-top boxes are endowed with Smart TV capabilities. Those include computing and connectivity to online services such as video on demand, online games and even sports and healthcare. A lot of Smart TV devices also have built-in cameras, microphones and other sensors that provide for environmental monitoring and consequent context dependent feedback. Such Smart TV capabilities, however, can lead to privacy violations through unwanted tracking and user profiling by broadcasters and other service providers. There is a concern when underage users such as children who may not fully understand the concept of privacy are involved in using the Smart TV services. To address this issue, face recognition experiments were conducted with the IBM\u27s Watson and the Microsoft\u27s Face Application Programming Interface to reveal the potential of integrating facial recognition in future privacy aware Smart TV services

    Mechanical motion promotes expression of Prg4 in articular cartilage via multiple CREB-dependent, fluid flow shear stress-induced signaling pathways

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    Lubricin is a secreted proteoglycan encoded by the Prg4 locus that is abundantly expressed by superficial zone articular chondrocytes and has been noted to both be sensitive to mechanical loading and protect against the development of osteoarthritis. In this study, we document that running induces maximal expression of Prg4 in the superficial zone of knee joint articular cartilage in a COX-2-dependent fashion, which correlates with augmented levels of phospho-S133 CREB and increased nuclear localization of CREB-regulated transcriptional coactivators (CRTCs) in this tissue. Furthermore, we found that fluid flow shear stress (FFSS) increases secretion of extracellular PGE2, PTHrP, and ATP (by epiphyseal chondrocytes), which together engage both PKA- and Ca++-regulated signaling pathways that work in combination to promote CREB-dependent induction of Prg4, specifically in superficial zone articular chondrocytes. Because running and FFSS both boost Prg4 expression in a COX-2-dependent fashion, our results suggest that mechanical motion may induce Prg4 expression in the superficial zone of articular cartilage by engaging the same signaling pathways activated in vitro by FFSS that promote CREB-dependent gene expression in this tissue.National Institute of Arthritis and Musculoskeletal and Skin Diseases (U.S.) (Grant AR60331

    Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides

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    The NSF is thanked for purchase of a JEOL ECS-400 NMR Spectrometer (CRIF-MU CHE-1048553).The synthesis, structures and reactivity of the spirocyclic yttrium and lanthanum disiloxides {[(CH2R2SiO)2]2M}H [M = Ln, Y; R = SiMe(SiMe3)2] 3 and 4 are reported. Compounds 3 and 4 were prepared from reactions of two equivalents of [CH2(R)2SiOH]2 [R = Si(SiMe3)2Me] ( 1 ) with one equivalent of M[N(SiMe3)2]2 (M = Y, La), respectively.PostprintPeer reviewe

    Kernelization and Parameterized Algorithms for 3-Path Vertex Cover

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    A 3-path vertex cover in a graph is a vertex subset CC such that every path of three vertices contains at least one vertex from CC. The parameterized 3-path vertex cover problem asks whether a graph has a 3-path vertex cover of size at most kk. In this paper, we give a kernel of 5k5k vertices and an O(1.7485k)O^*(1.7485^k)-time and polynomial-space algorithm for this problem, both new results improve previous known bounds.Comment: in TAMC 2016, LNCS 9796, 201
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