13,428 research outputs found
Separability and radial asymptotic behaviour of the Dirac equation and integral spectral representation for the Dirac propagator in the 5D Myers-Perry geometry in Eddington-Finkelstein-type coordinates
We analytically extend the 5D Myers-Perry metric through the event and Cauchy
horizons by defining Eddington-Finkelstein-type coordinates. We then use the
orthonormal frame formalism to formulate and perform separation of variables on
the massive Dirac equation, and analyse the asymptotic behaviour at the
horizons and at infinity of the solutions to the radial ODE thus obtained, as
was done by R\"oken in the Kerr geometry. Using the essential self-adjointness
result of Finster and R\"oken and Stone's formula, we obtain an integral
spectral representation of the Dirac propagator in terms of resolvents of the
Dirac Hamiltonian, which can in turn be expressed in terms of Green's functions
of the radial ODE.Comment: 22 page
Local Dirac energy decay in the 5D Myers-Perry geometry using an integral spectral representation for the Dirac propagator
We consider the massive Dirac equation in the exterior region of the
5-dimensional Myers-Perry black hole. Using the resulting ODEs obtained from
the separation of variables of the Dirac equation, we construct an integral
spectral representation for the solution of the Cauchy problem with compactly
supported smooth initial data. We then prove that the probability of presence
of a Dirac particle to be in any compact region of space decays to zero as
, in analogy with the case of the Dirac operator in the Kerr-Newman
geometry.Comment: 13 pages, fixed typographic error
The dependence of the IR-radio correlation on the metallicity
We have compiled a sample of 26 metal-poor galaxies with 12 + log(O/H) < 8.1
with both infrared continuum and 1.4 GHz radio continuum data. By comparing to
galaxies at higher metallicity, we have investigated the dependence on the
metallicity of the IR-radio relationship at 24 um, 70 um, 100 um and 160 um
bands as well as the integrated FIR luminosity. It is found that metal-poor
galaxies have on average lower qIR than metal-rich ones with larger offsets at
longer IR wavelengths, from -0.06 dex in q24um to -0.6 dex in q160um. The qIR
of all galaxies as a whole at 160 um show positive trends with the metallicity
and IR-to-FUV ratio, and negative trends with the IR color, while those at
lower IR wavelengths show weaker correlations. We proposed a mechanism that
invokes combined effects of low obscured-SFR/total-SFR fraction and warm dust
temperature at low metallicity to interpret the above behavior of qIR, with the
former reducing the IR radiation and the latter further reducing the IR
emission at longer IR wavelength. Other mechanisms that are related to the
radio emission including the enhanced magnetic field strength and increased
thermal radio contribution are unable to reconcile the IR-wavelength-dependent
differences of qIR between metal-poor and metal- rich galaxies. In contrast to
qIR, the mean total-SFR/radio ratio of metal-poor galaxies is the same as the
metal-rich one, indicating the 1.4 GHz radio emission is still an effective
tracer of SFRs at low metallicity.Comment: 25 pages, 11 figures, 4 tables. ApJ in pres
2-Methyl-2,4-di-4-pyridyl-2,3-dihydro-1H-1,5-benzodiazepine acetic acid solvate
In the title compound, C20H18N4·CH3COOH, the benzene ring forms dihedral angles of 81.34 (11) and 54.32 (11)° with the two pyridine rings. In the crystal, intermolecular O—H⋯N hydrogen bonding links one 1,5-benzodiazepine molecule and one acetic acid solvent molecule into a dimer. These dimers, related by translation along the b axis, are further linked into chains via weak intermolecular N—H⋯N hydrogen bonds
Comparison of the short term therapeutic effects by different incision triple surgery in treating angle-closure glaucoma with cataract
AIM:To compare the therapeutic effects of different incision phacoemulsification with foldable intraocular lens implantation combined with trabeculectomy in treating angle-closure glaucoma complicated with cataract. <p>METHODS: The retrospective study analyzed 70 patients(98 eyes)who performed phacoemulsification with foldable intraocular lens implantation combined with trabeculectomy. Single incision surgery(one-site approach)was performed on 34 patients(50 eyes), and double incision surgery(two-site approaches)was done on 36 patients(48 eyes). The differences of intraocular pressure control,filtering bleb, the density and preservation of corneal endothelium cells both pre-surgery and 1 month post-surgery or later complication. in the two groups were compared and analyzed.Follow-up was 12-24 months with a mean of 18.2 months.<p>RESULTS: The average postoperative intraocular pressure in one-site groups was(10.16±4.31)mmHg. The average postoperative intraocular pressure in two-site groups was(11.38±3.55)mmHg. There were no statistically significant differences between the two groups(<i>P</i>>0.05)regarding the postoperative intraocular pressure and the formation of filtering blebs(<i>P</i>>0.05). The density and area of corneal endothelium cells in the two-incision group pre-operation were comparable(<i>P</i>>0.05). However, in 1 month post-operation, the rate of the corneal endothelial cells loss in double incision group was superior compared to the single incision group(<i>P</i><0.01).<p>CONCLUSION: Both single incision and double incision approach phacotrabeculectomy are effective in reducing intraocular pressure and can maintain the function of filtering blebs well. There are no statistically significant differences in the intraocular pressure reduction between the two approaches. The double incision approach is superior in minimizing the corneal endothelial cells loss compared to the single incision approach
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