70,531 research outputs found
The effect of an isothermal atmosphere on the propagation of three-dimensional waves in a thermally stratified accretion disk
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
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'''
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
Measurements of the magnetic field penetration depth in the ternary
boride superconductor LiPdB ( K) have been carried out by
means of muon-spin rotation (SR). The absolute values of , the
Ginzburg-Landau parameter , and the first and the second
critical fields at T=0 obtained from SR were found to be
nm, , mT, and
T, respectively. The zero-temperature value of the
superconducting gap 1.31(3) meV was found, corresponding to the
ratio . At low temperatures saturates and
becomes constant below , in agreement with what is expected for
s-wave BCS superconductors. Our results suggest that LiPdB 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
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 BaKFeAs Probed by Fe-NMR
We present Fe-NMR measurements of the novel normal and
superconducting-state characteristics of the iron-arsenide superconductor
BaKFeAs ( = 38 K). In the normal state, the
measured Knight shift and nuclear spin-lattice relaxation rate
demonstrate the development of wave-number ()-dependent spin fluctuations,
except at = 0, which may originate from the nesting across the disconnected
Fermi surfaces. In the superconducting state, the spin component in the
Fe-Knight shift decreases to almost zero at low temperatures, evidencing
a spin-singlet superconducting state. The Fe- results are totally
consistent with a -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
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
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
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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