70,531 research outputs found

    The effect of an isothermal atmosphere on the propagation of three-dimensional waves in a thermally stratified accretion disk

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    We extend our analysis of the three-dimensional response of a vertically polytropic disk to tidal forcing at Lindblad resonances by including the effects of a disk atmosphere. The atmosphere is modeled as an isothermal layer that joins smoothly on to an underlying polytropic layer. The launched wave progressively enters the atmosphere as it propagates away from the resonance. The wave never propagates vertically, however, and the wave energy rises to a (finite) characteristic height in the atmosphere. The increase of wave amplitude associated with this process of wave channeling is reduced by the effect of the atmosphere. For waves of large azimuthal mode number m generated by giant planets embedded in a disk, the increase in wave amplitude is still substantial enough to be likely to dissipate the wave energy by shocks for even modest optical depths (tau greater than about 10) over a radial distance of a few times the disk thickness. For low-m waves generated in circumstellar disks in binary stars, the effects of wave channeling are less important and the level of wave nonlinearity increases by less than a factor of 10 in going from the disk edge to the disk center. For circumbinary disks, the effects of wave channeling remain important, even for modest values of optical depth.Comment: 11 pages, 4 figures, submitted to the Astrophysical Journa

    Molecule mapping of HR8799b using OSIRIS on Keck: Strong detection of water and carbon monoxide, but no methane

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    Context. In 2015, Barman et al. (ApJ, 804, 61) presented detections of absorption from water, carbon monoxide, and methane in the atmosphere of the directly imaged exoplanet HR8799b using integral field spectroscopy (IFS) with OSIRIS on the Keck II telescope. We recently devised a new method to analyse IFU data, called molecule mapping, searching for high-frequency signatures of particular molecules in an IFU data cube. Aims. The aim of this paper is to use the molecule mapping technique to search for the previously detected spectral signatures in HR8799b using the same data, allowing a comparison of molecule mapping with previous methods. Methods. The medium-resolution H- and K-band pipeline-reduced archival data were retrieved from the Keck archive facility. Telluric and stellar lines were removed from each spectrum in the data cube, after which the residuals were cross-correlated with model spectra of carbon monoxide, water, and methane. Results. Both carbon monoxide and water are clearly detected at high signal-to-noise, however, methane is not retrieved. Conclusions. Molecule mapping works very well on the OSIRIS data of exoplanet HR8799b. However, it is not evident why methane is detected in the original analysis, but not with the molecule mapping technique. Possible causes could be the presence of telluric residuals, different spectral filtering techniques, or the use of different methane models. We do note that in the original analysis methane was only detected in the K-band, while the H-band methane signal could be expected to be comparably strong. More sensitive observations with the JWST will be capable of confirming or disproving the presence of methane in this planet at high confidence.Comment: 5 pages, 5 figures and 2 tables, accepted by A&

    Reply to ``Comment on `On the inconsistency of the Bohm-Gadella theory with quantum mechanics'''

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    In this reply, we show that when we apply standard distribution theory to the Lippmann-Schwinger equation, the resulting spaces of test functions would comply with the Hardy axiom only if classic results of Paley and Wiener, of Gelfand and Shilov, and of the theory of ultradistributions were wrong. As well, we point out several differences between the ``standard method'' of constructing rigged Hilbert spaces in quantum mechanics and the method used in Time Asymmetric Quantum Theory.Comment: 13 page

    Muon-spin-rotation measurements of the penetration depth in Li_2Pd_3B

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    Measurements of the magnetic field penetration depth λ\lambda in the ternary boride superconductor Li2_2Pd3_3B (Tc7.3T_c\simeq7.3 K) have been carried out by means of muon-spin rotation (μ\muSR). The absolute values of λ\lambda, the Ginzburg-Landau parameter κ\kappa, and the first Hc1H_{c1} and the second Hc2H_{c2} critical fields at T=0 obtained from μ\muSR were found to be λ(0)=252(2)\lambda(0)=252(2) nm, κ(0)=27(1)\kappa(0)=27(1), μ0Hc1(0)=9.5(1)\mu_0H_{c1}(0)=9.5(1) mT, and μ0Hc2(0)=3.66(8)\mu_0H_{c2}(0)=3.66(8) T, respectively. The zero-temperature value of the superconducting gap Δ0=\Delta_0=1.31(3) meV was found, corresponding to the ratio 2Δ0/kBTc=4.0(1)2\Delta_0/k_BT_c=4.0(1). At low temperatures λ(T)\lambda(T) saturates and becomes constant below T0.2TcT\simeq 0.2T_c, in agreement with what is expected for s-wave BCS superconductors. Our results suggest that Li2_2Pd3_3B is a s-wave BCS superconductor with the only one isotropic energy gap.Comment: 6 pages, 7 figure

    Institusionalisasi Partai Politk: Studi Kasus Hegemoni Pan di Sulawesi Tenggara

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    Focus articles namely institusionalizationpolitical party with case study PAN Southeast Sulawesi.Although nationally PAN occupy a board the middle , but in Southeast Sulawesi occupy the top.Hegemony PANSoutheast Sulawesi seen in the seats at an election 2004,2009, 2014 and the fight for regional head election (Pilkada) carried out the period 2010-2013.It was just that , hegemony PAN did not come from institusionalization politicalparty but based on the power of personal. The beginning formation of the process ofinstitusionalization in line with onthe track , but in the following development this process is not workingbecause of the emergence of a strong personalize them in the body of internal pan namely Nur Alam.The figure of this is so strong so as to create patronage both in internal party and exit.To create a voter loyalty, then introduced the program BAHTERAMAS which included the types of programmatic goods.As a result, PAN experienced a dilemma because the process institusionalization politicalparty did not function as intended and program design is not sustainable. Strengthening personalize them in the body party because institusionalizationof the weak. This situation should anticipated by the party, if the party rely on the strength of figure, when he has no base material and resources strong , but political parties will also weakened

    Strong-coupling Spin-singlet Superconductivity with Multiple Full Gaps in Hole-doped Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 Probed by Fe-NMR

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    We present 57^{57}Fe-NMR measurements of the novel normal and superconducting-state characteristics of the iron-arsenide superconductor Ba0.6_{0.6}K0.4_{0.4}Fe2_2As2_2 (TcT_c = 38 K). In the normal state, the measured Knight shift and nuclear spin-lattice relaxation rate (1/T1)(1/T_1) demonstrate the development of wave-number (qq)-dependent spin fluctuations, except at qq = 0, which may originate from the nesting across the disconnected Fermi surfaces. In the superconducting state, the spin component in the 57^{57}Fe-Knight shift decreases to almost zero at low temperatures, evidencing a spin-singlet superconducting state. The 57^{57}Fe-1/T11/T_1 results are totally consistent with a s±s^\pm-wave model with multiple full gaps, regardless of doping with either electrons or holes.Comment: 4 pages, 4 figures, 1 tabl

    The rigged Hilbert space approach to the Lippmann-Schwinger equation. Part II: The analytic continuation of the Lippmann-Schwinger bras and kets

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    The analytic continuation of the Lippmann-Schwinger bras and kets is obtained and characterized. It is shown that the natural mathematical setting for the analytic continuation of the solutions of the Lippmann-Schwinger equation is the rigged Hilbert space rather than just the Hilbert space. It is also argued that this analytic continuation entails the imposition of a time asymmetric boundary condition upon the group time evolution, resulting into a semigroup time evolution. Physically, the semigroup time evolution is simply a (retarded or advanced) propagator.Comment: 32 pages, 3 figure

    Outcome of renal grafts after simultaneous kidney/ pancreas transplantation

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    Nineteen patients with endstage renal failure due to Type 1 (insulin-dependent) diabetes mellitus received simultaneous pancreas/kidney transplants using bladder drainage technique. Another group of 25 Type 1 diabetic patients received pancreas/kidney transplants by the duct occlusion technique. We observed a higher incidence of rejection episodes in the patients of the bladder drainage group than those in the duct occlusion group, 14 of 19 patients (74%) vs 7 of 25 (28%) respectively. Anti CD3 antibodies (Orthoclone, OKT3) as a part of induction treatment was used more often in the bladder drainage group (58%) than in the control group (20%)

    Applications of p-deficiency and p-largeness

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    We use Schlage-Puchta's concept of p-deficiency and Lackenby's property of p-largeness to show that a group having a finite presentation with p-deficiency greater than 1 is large, which implies that Schlage-Puchta's infinite finitely generated p-groups are not finitely presented. We also show that for all primes p at least 7, any group having a presentation of p-deficiency greater than 1 is Golod-Shafarevich, and has a finite index subgroup which is Golod-Shafarevich for the remaining primes. We also generalise a result of Grigorchuk on Coxeter groups to odd primes.Comment: 23 page
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