7,961 research outputs found
On the Profiles and Polarization of Raman Scattered Emission Lines in Symbiotic Stars:II. Numerical Simulations
A Monte Carlo method is used to calculate the profiles and the polarization
of the Raman scattered O VI lines(lambda lambda 6827,7088) in symbiotic stars.
A point-like isotropic UV radiation source is assumed and a simple spherical
wind model is adopted for the kinematics of the scattering material from the
cool giant. We first investigate the case where the incident line photons are
described by a Gaussian profile having a width of 10^4 K. We subsequently
investigate the effects of the extended ionized region and non-spherical wind
models including a disk-type wind and a bipolar wind. The cases where the
emissin source is described by non-Gaussian profiles are briefly studied.
Finally, as an additional component for the kinematics of symbiotic stars the
orbital motion of the hot component around the cool giant is included and the
effect on the spectropolarimetry is investigated. In this case the polarization
direction changes around the red part of the Raman-scattered emission lines,
when the observer's line of sight is perpendicular to the orbital plane, and no
such effect is seen when the line of sight lies in the orbital plane.
Furthermore, complex peak structures are seen in the degree of polarization and
polarized flux, which have often been observed in several symbiotic systems
including RR Tel. Brief observational consequences and preditions are discussed
in relation to the present and future spectropolarimetry for symbiotic stars.
It is concluded that spectropolarimetry may provide a powerful diagnostic of
the physical conditions of symbiotic stars.Comment: 22 pages, Tex, 15 postscript figuer
Multi-frequency imaging of perfectly conducting cracks via boundary measurements
Imaging of perfectly conducting crack(s) in a 2-D homogeneous medium using
boundary data is studied. Based on the singular structure of the Multi-Static
Response (MSR) matrix whose elements are normalized by an adequate test
function at several frequencies, an imaging functional is introduced and
analyzed. A non-iterative imaging procedure is proposed. Numerical experiments
from noisy synthetic data show that acceptable images of single and multiple
cracks are obtained.Comment: 4 pages, 3 figure
SHORTFALLS IN 1997 NET FARM INCOME IN NORTH DAKOTA (Prepared for Senators Byron Dorgan and Kent Conrad)
North Dakota net farm income declined in 1997 due to adverse weather conditions and low prices. The total income loss in 1997 was estimated to be 290 million due to weather and diseases, and $104 million due to lower-than-average prices. Net farm income losses were largest in Region 3 (Northeast), followed by Regions 1 (Northwest) and 6 (East Central). HRS wheat accounted for the largest income loss, followed by durum and barley.Net farm income, crop losses, weather conditions, North Dakota input output model, Agricultural Finance,
Thermophysical and elastic properties of Cu50Zr50 and (Cu50Zr50)95Al5 bulk-metallic-glass-forming alloys
By employing a containerless high-temperature high-vacuum electrostatic levitation technique, the thermophysical properties, including the ratio between the specific heat capacity and the hemispherical total emissivity, the specific volume, and the viscosity, of Cu50Zr50 and (Cu50Zr50)95Al5 bulk-metallic-glass (BMG)-forming liquids have been measured. Compared with Cu50Zr50, the improved glass-forming ability of (Cu50Zr50)95Al5 can be attributed to its dense liquid structure and its high value of viscosity. Additionally, the relationship between the viscosity of various BMG forming liquids at the melting temperature and the elastic properties of the corresponding glasses at room temperature will be compared
Bilateral herpetic keratitis presenting with unilateral neurotrophic keratitis in pemphigus foliaceus: a case report
<p>Abstract</p> <p>Introduction</p> <p>We report a case of bilateral herpetic keratitis developing after rapid oral corticosteroid tapering in a patient with pemphigus foliaceus, which was followed by unilateral neurotrophic keratitis that was treated with amniotic membrane transplantation.</p> <p>Case presentation</p> <p>A 71-year-old Korean man developed bilateral herpetic keratitis one week after rapid tapering of systemic corticosteroid. He had been on high-dose oral corticosteroid and azathioprine therapy for six months for treatment of pemphigus foliaceus. Topical acyclovir ointment was prescribed. A week later, our patient's right eye had healed, but his left eye showed increased stromal edema with enlarged epithelial defects. He was prescribed oral acyclovir with topical broad-spectrum antibiotics applied to his left eye. The stromal edema cleared within a week but the epithelial defect remained unchanged. An amniotic membrane transplantation was performed on our patient's left eye, and his epithelial defect had totally healed three weeks later.</p> <p>Conclusions</p> <p>Patients with autoimmune disease or who are on immunosuppressive therapy have a higher chance of developing bilateral herpetic keratitis. Although rare, the condition may be followed by unilateral neurotrophic keratitis. Rapid corticosteroid tapering may act as a triggering factor for viral infection or reactivation of herpes.</p
Quantum Key Distribution with High Loss: Toward Global Secure Communication
We propose a decoy-state method to overcome the photon-number-splitting
attack for Bennett-Brassard 1984 quantum key distribution protocol in the
presence of high loss: A legitimate user intentionally and randomly replaces
signal pulses by multi-photon pulses (decoy-states). Then they check the loss
of the decoy-states. If the loss of the decoy-states is abnormally less than
that of signal pulses, the whole protocol is aborted. Otherwise, to continue
the protocol, they estimate loss of signal multi-photon pulses based on that of
decoy-states. This estimation can be done with an assumption that the two
losses have similar values, that we justify.Comment: derivation made more detailed, 4 pages, RevTe
Anisotropy of in-plane magnetization due to nodal gap structure in the vortex state
We examine the interplay between anisotropy of the in-plane magnetization and
the nodal gap structure on the basis of the approximate analytic solution in
the quasiclassical formalism. We show that a four-fold oscillation appears in
the magnetization, and its amplitude changes sign at an intermediate field. The
high-field oscillation originates from the anisotropy of the upper critical
field, while the low-field behavior can be understood by the thermally
activated quasiparticles near nodes depending on the applied field angles. The
temperature dependence of the magnetization also shows a similar sign change.
The anisotropy of the magnetization offers a possible measurement to identify
the gap structure directly for a wide class of type II superconductors.Comment: 4 pages, 4 figure
Transport and the Order Parameter of Superconducting SrRuO
Recent experiments make it appear more likely that the order parameter of the
unconventional superconductor SrRuO has a spin-triplet -wave
symmetry. We study ultrasonic absorption and thermal conductivity of
superconducting SrRuO and fit to the recent data for various -wave
candidates. It is shown that only -wave symmetry can account
qualitatively for the transport data.Comment: 4 pages, 2 figures, references added and update
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