Convergence of numerical schemes for short wave long wave interaction equations

We consider the numerical approximation of a system of partial differential equations involving a nonlinear Schr\"odinger equation coupled with a hyperbolic conservation law. This system arises in models for the interaction of short and long waves. Using the compensated compactness method, we prove convergence of approximate solutions generated by semi-discrete finite volume type methods towards the unique entropy solution of the Cauchy problem. Some numerical examples are presented.Comment: 31 pages, 7 figure

The Variability of Sagittarius A* at Centimeter Wavelengths

We present the results of a 3.3-year project to monitor the flux density of Sagittarius A* at 2.0, 1.3, and 0.7 cm with the VLA. The fully calibrated light curves for Sgr A* at all three wavelengths are presented. Typical errors in the flux density are 6.1%, 6.2%, and 9.2% at 2.0, 1.3, and 0.7 cm, respectively. There is preliminary evidence for a bimodal distribution of flux densities, which may indicate the existence of two distinct states of accretion onto the supermassive black hole. At 1.3 and 0.7 cm, there is a tail in the distribution towards high flux densities. Significant variability is detected at all three wavelengths, with the largest amplitude variations occurring at 0.7 cm. The rms deviation of the flux density of Sgr A* is 0.13, 0.16, and 0.21 Jy at 2.0, 1.3, and 0.7 cm, respectively. During much of this monitoring campaign, Sgr A* appeared to be relatively quiescent compared to results from previous campaigns. At no point during the monitoring campaign did the flux density of Sgr A* more than double its mean value. The mean spectral index of Sgr A* is alpha=0.20+/-0.01, with a standard deviation of 0.14. The spectral index appears to depend linearly on the observed flux density at 0.7 cm with a steeper index observed during outbursts. This correlation is consistent with the expectation for outbursts that are self-absorbed at wavelengths of 0.7 cm or longer and inconsistent with the effects of simple models for interstellar scintillation. Much of the variability of Sgr A*, including possible time lags between flux density changes at the different wavelengths, appears to occur on time scales less than the time resolution of our observations (8 days). Future observations should focus on the evolution of the flux density on these time scales.Comment: 16 pages, 10 figures, accepted for publication in A

Linear vs. nonlinear effects for nonlinear Schrodinger equations with potential

We review some recent results on nonlinear Schrodinger equations with potential, with emphasis on the case where the potential is a second order polynomial, for which the interaction between the linear dynamics caused by the potential, and the nonlinear effects, can be described quite precisely. This includes semi-classical regimes, as well as finite time blow-up and scattering issues. We present the tools used for these problems, as well as their limitations, and outline the arguments of the proofs.Comment: 20 pages; survey of previous result

Arctic and Antarctic polar mesosphere summer echoes observed with oblique incidence HF radars: analysis using simultaneous MF and VHF radar data

Polar mesosphere summer echoes (PMSEs) have been well studied using vertical incidence VHF radars at northern high-latitudes. In this paper, two PMSE events detected with the oblique incidence SuperDARN HF radars at Hankasalmi, Finland (62.3° N) and Syowa Station, Antarctica (69.0° S), are analyzed, together with simultaneous VHF and medium-frequency (MF) radar data. Altitude resolutions of the HF radars in the mesosphere and the lower thermosphere are too poor to know exact PMSE altitudes. However, a comparison of Doppler velocity from the HF radar and neutral wind velocity from the MF radar shows that PMSEs at the HF band appeared at altitudes within 80-90km, which are consistent with those from previous vertical incidence HF-VHF radar results. The HF-VHF PMSE occurrences exhibit a semidiurnal behavior, as observed by other researchers. It is found that in one event, PMSEs occurred when westward semidiurnal winds with large amplitude at 85-88km altitudes attained a maximum. When the HF-VHF PMSEs were observed at distances beyond 180km from MF radar sites, the MF radars detected no appreciable signatures of echo enhancement. <br><br><b>Key words.</b> Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides

Acoustic radiation controls friction: Evidence from a spring-block experiment

Brittle failures of materials and earthquakes generate acoustic/seismic waves which lead to radiation damping feedbacks that should be introduced in the dynamical equations of crack motion. We present direct experimental evidence of the importance of this feedback on the acoustic noise spectrum of well-controlled spring-block sliding experiments performed on a variety of smooth surfaces. The full noise spectrum is quantitatively explained by a simple noisy harmonic oscillator equation with a radiation damping force proportional to the derivative of the acceleration, added to a standard viscous term.Comment: 4 pages including 3 figures. Replaced with version accepted in PR

Caracterização morfológica de estirpes de rizóbio obtidos de nódulos de feijoeiro.

bitstream/item/148283/1/7-caracterizacao-morfologica.pd

Intra-Day Variation of Sagittarius A* at Short Millimeter Wavelengths

We have performed the monitoring observations of flux density of Sagittarius A* at short millimeter wavelengths (100 and 140 GHz bands) on seven years in the period from 1996 to 2003 using the Nobeyama Millimeter Array (NMA). We found intra-day variation of Sgr A* in March 2000 flare. The flux density at the peak of the flares increases 100-200 % at 100 GHz and 200-400 % at 140 GHz ($?Delta S/S$), respectively. The two-fold increase timescale of the flare is estimated to be about 1.5 hours at 140 GHz. The intra-day variation at mm-wavelengths has similar increase timescale as those in the X-ray and infrared flares but has smaller amplitude. This short timescale variability suggests that the physical size of the emitting region is smaller than 12 AU $?approx$ 150 Rs). The decay timescale of the flare was at most 24 hours. Such a light curve with rapid increase and slow decay is similar to that often observed in outburst phenomena with ejections.Comment: 13 pages, 3 figures, Accepted for publication in ApJ

Histopathological diagnosis of Japanese spotted fever using formalin-fixed, paraffin-embedded skin biopsy specimens Usefulness of immunohistochemistry and real-time PCR analysis

AbstractJapanese spotted fever (JSF) is caused by Rickettsia japonica, and lethal cases are reported yearly in southwest Japan. We thus established the method of diagnosing JSF by immunohistochemistry (IHC) and real-time PCR (RT-PCR) using formalin-fixed, paraffin-embedded skin biopsy specimens. Two monoclonal antibodies were used for IHC, and the 17k genus common antigen gene served as the target of RT-PCR. We collected skin biopsy (n = 61) and autopsy (n = 1) specimens from 50 patients clinically suspected of JSF. Immunohistochemically, the rickettsial antigens were localized as coarse dots in the cytoplasm of endothelial cells and macrophages. Thirty-one seropositive cases plus one autopsy case (group A) and nine seronegative cases but with positive IHC and/or RT-PCR (group B) were judged as JSF. Nine cases were regarded as non-JSF disorders based on negative serology, IHC and RT-PCR (group C). Of 50 biopsies (eschar 34, eruptions 10, and scabs 6) from groups A and B, IHC and RT-PCR positivities were 94% (32/34) and 62% (21/34) for eschar, 80% (8/10) and 30% (3/10) for eruptions, and 33% (2/6) and 50% (3/6) for scabs. For IHC, eschar was most suitable, and scabs were insufficient. Unexpectedly, 18 biopsies happened to be fixed in 100% formalin, and this lowered the detection rate by RT-PCR, but IHC was tolerant. Sequence analysis using five skin biopsy specimens confirmed a 114 bp DNA stretch homologous to that reported for the target gene of R. japonica. In 26 (84%) of the 31 seropositive patients, the diagnosis was made by IHC and/or RT-PCR earlier than serology