15,792 research outputs found

    The colour of the narrow line Sy1-blazar 0324+3410

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    Aims. We investigate the properties of the host galaxy of the blazar J0324+3410 (B2 0321+33) by the analysis of B and R images obtained with the NOT under good photometric conditions. Methods: The galaxy was studied using different methods: Sersic model fitting, unsharp-masked images, B-R image and B-R profile analysis. Results: The images show that the host galaxy has a ring-like morphology. The B-R colour image reveals two bluish zones: one that coincides with the nuclear region, interpreted as the signature of emission related to the active nucleus, the other zone is extended and is located in the host ring-structure. We discuss the hypothesis that the later is thermal emission from a burst of star formation triggered by an interacting/merging process

    Young's experiment and the finiteness of information

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    Young's experiment is the quintessential quantum experiment. It is argued here that quantum interference is a consequence of the finiteness of information. The observer has the choice whether that information manifests itself as path information or in the interference pattern or in both partially to the extent defined by the finiteness of information.Comment: 5 pages, 3 figures, typos remove

    Generation of slow intense optical solitons in a resonance photonic crystal

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    We demonstrate interesting and previously unforeseen properties of a pair of gap solitons in a resonant photonic crystal which are predicted and explained in a physically transparent form using both analytical and numerical methods. The most important result is the fact that an oscillating gap soliton created by the presence of a localized population inversion inside the crystal can be manipulated by means of a proper choice of bit rate, phase and amplitude modulation. Developing this idea, we are able to obtain qualitatively different regimes of a resonant photonic crystal operation. In particular, a noteworthy observation is that both the delay time and amplitude difference must exceed a certain level to ensure effective control over the soliton dynamics

    Spatial fluctuations of a surviving particle in the trapping reaction

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    We consider the trapping reaction, A+BBA+B\to B, where AA and BB particles have a diffusive dynamics characterized by diffusion constants DAD_A and DBD_B. The interaction with BB particles can be formally incorporated in an effective dynamics for one AA particle as was recently shown by Bray {\it et al}. [Phys. Rev. E {\bf 67}, 060102 (2003)]. We use this method to compute, in space dimension d=1d=1, the asymptotic behaviour of the spatial fluctuation, 1/2^{1/2}, for a surviving AA particle in the perturbative regime, DA/DB1D_A/D_B\ll 1, for the case of an initially uniform distribution of BB particles. We show that, for t1t\gg 1, 1/2tϕ^{1/2} \propto t^{\phi} with ϕ=1/4\phi=1/4. By contrast, the fluctuations of paths constrained to return to their starting point at time tt grow with the larger exponent 1/3. Numerical tests are consistent with these predictions.Comment: 10 pages, 5 figure

    Perbandingan Ppc Dan Faktor-faktor Yang Mempengaruhi Pada Dua Proyek Apartemen

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    Dalam perkembangan dunia konstruksi yang semakin komplek, sering terjadi pekerjaan yang tidak dapat diselesaikan sesuai dengan jadwal perencanaan yang ada pada action plan. Penelitian ini bertujuan untuk menilai suatu perencanaan proyek dengan menghitung Percent Plan Completed dan juga mendapatkan faktor-faktor penyebab tidak tercapainya rencana pekerjaan (Reason Not Complete). Hal ini dilakukan dengan menerapkan kontrol aliran kerja yang berkesinambungan agar perencanaan menjadi lebih handal. Selain itu juga akan diteliti mengenai penggunaan kontrol aliran kerja sistem last planner pada suatu proyek konstruksi. Penelitian ini telah dilakukan selama 19 minggu. Hasil penelitian menunjukkan bahwa rata-rata PPC (Percent Plan Completed) sebesar 61,15% dan 57,32%, kemudian faktor penyebab dominan tidak terselesaikannya pekerjaan dalam proyek ini adalah faktor predecessor. Selain itu proyek yang diamati ini sedikit melakukan kontrol aliran kerja sistem last planner. Dimana aliran kerja yang dilakukan yaitu action plan2 mingguan dan daily meeting yang dilakukan seminggu sekali

    Interface enhancement of Gilbert damping from first-principles

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    The enhancement of Gilbert damping observed for Ni80Fe20 (Py) films in contact with the non-magnetic metals Cu, Pd, Ta and Pt, is quantitatively reproduced using first-principles scattering theory. The "spin-pumping" theory that qualitatively explains its dependence on the Py thickness is generalized to include a number of factors known to be important for spin transport through interfaces. Determining the parameters in this theory from first-principles shows that interface spin-flipping makes an essential contribution to the damping enhancement. Without it, a much shorter spin-flip diffusion length for Pt would be needed than the value we calculate independently

    Ni(111)|Graphene|h-BN Junctions as Ideal Spin Injectors

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    Deposition of graphene on top of hexagonal boron nitride (h-BN) was very recently demonstrated while graphene is now routinely grown on Ni. Because the in-plane lattice constants of graphite, h-BN, graphite-like BC2N and of the close-packed surfaces of Co, Ni and Cu match almost perfectly, it should be possible to prepare ideal interfaces between these materials which are respectively, a semimetal, insulator, semiconductor, ferromagnetic and nonmagnetic metals. Using parameter-free energy minimization and electronic transport calculations, we show how h-BN can be combined with the perfect spin filtering property of Ni|graphite and Co|graphite interfaces to make perfect tunnel junctions or ideal spin injectors (SI) with any desired resistance-area product.Comment: 4 pages, 4 figures. Accepted for publication in Physical Review

    The structure of one-relator relative presentations and their centres

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    Suppose that G is a nontrivial torsion-free group and w is a word in the alphabet G\cup\{x_1^{\pm1},...,x_n^{\pm1}\} such that the word w' obtained from w by erasing all letters belonging to G is not a proper power in the free group F(x_1,...,x_n). We show how to reduce the study of the relative presentation \^G= to the case n=1. It turns out that an "n-variable" group \^G can be constructed from similar "one-variable" groups using an explicit construction similar to wreath product. As an illustration, we prove that, for n>1, the centre of \^G is always trivial. For n=1, the centre of \^G is also almost always trivial; there are several exceptions, and all of them are known.Comment: 15 pages. A Russian version of this paper is at http://mech.math.msu.su/department/algebra/staff/klyachko/papers.htm . V4: the intoduction is rewritten; Section 1 is extended; a short introduction to Secton 5 is added; some misprints are corrected and some cosmetic improvements are mad
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