Orbital Characteristics of the Subdwarf-B and F V Star Binary EC~20117-4014(=V4640 Sgr)

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion (O'Donoghue et al. 1997), however the period and the orbit semi-major axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic Observed minus Calculated (O-C) variations were detected in the two highest amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system's precise orbital period (P = 792.3 days) and the light-travel time amplitude (A = 468.9 s). This binary shows no significant orbital eccentricity and the upper limit of the eccentricity is 0.025 (using 3 $\sigma$ as an upper limit). This upper limit of the eccentricity is the lowest among all wide sdB binaries with known orbital parameters. This analysis indicated that the sdB is likely to have lost its hydrogen envelope through stable Roche lobe overflow, thus supporting hypotheses for the origin of sdB stars. In addition to those results, the underlying pulsation period change obtained from the photometric data was $\dot{P}$ = 5.4 ($\pm$0.7) $\times$ $10^{-14}$ d d$^{-1}$, which shows that the sdB is just before the end of the core helium-burning phase

Rebuttal to "Comment by V.M. Krasnov on 'Counterintuitive consequence of heating in strongly-driven intrinsic junctions of Bi2Sr2CaCu2O8+d Mesas' "

In our article [1], we found that with increasing dissipation there is a clear, systematic shift and sharpening of the conductance peak along with the disappearance of the higher-bias dip/hump features (DHF), for a stack of intrinsic Josephson junctions (IJJs) of intercalated Bi2Sr2CaCu2O8+{\delta} (Bi2212). Our work agrees with Zhu et al [2] on unintercalated, pristine Bi2212, as both studies show the same systematic changes with dissipation. The broader peaks found with reduced dissipation [1,2] are consistent with broad peaks in the density-of-states (DOS) found among scanning tunneling spectroscopy [3] (STS), mechanical contact tunneling [4] (MCT) and inferred from angle (momentum) resolved photoemission spectroscopy [5] (ARPES); results that could not be ignored. Thus, sharp peaks are extrinsic and cannot correspond to the superconducting DOS. We suggested that the commonality of the sharp peaks in our conductance data, which is demonstrably shown to be heating-dominated, and the peaks of previous intrinsic tunneling spectroscopy (ITS) data implies that these ITS reports might need reinterpretation.Comment: Rebuttal to Comment of Krasnov arXiv:1007.451

Discovery of a Non-Thermal Galactic Center Filament (G358.85+0.47) Parallel to the Galactic Plane

We report the discovery of a new non-thermal filament, G358.85+0.47, the ``Pelican'', located ~225 pc in projection from SgrA, and oriented parallel to the Galactic plane. VLA continuum observations at 20 cm reveal that this 7' (17.5 pc) structure bends at its northern extension and is comprised of parallel strands, most apparent at its ends. Observations at 6 and 3.6 cm reveal that the Pelican is a synchrotron-emitting source and is strongly linearly polarized over much of its extent. The spectral index of the filament changes from alpha(20/6)=-0.8 to alpha(6/3.6)=-1.5. The rotation measures exhibit a smooth gradient, with values ranging from -1000 rad/m2 to +500 rad/m2. The intrinsic magnetic field is well-aligned along the length of the filament. Based on these properties, we classify the Pelican as one of the non-thermal filaments unique to the Galactic center. Since these filaments (most of which are oriented perpendicular to the Galactic plane) are believed to trace the overall magnetic field in the inner Galaxy, the Pelican is the first detection of a component of this field parallel to the plane. The Pelican may thus mark a transition region of the magnetic field orientation in the inner kiloparsec of the Galaxy.Comment: 6 pages, 4 figures, to appear in ApJ Letters; Figs. 2 & 3 are color .ps files and best viewed in colo

Tunneling study of cavity grade Nb: possible magnetic scattering at the surface

Tunneling spectroscopy was performed on Nb pieces prepared by the same processes used to etch and clean superconducting radio frequency (SRF) cavities. Air exposed, electropolished Nb exhibited a surface superconducting gap delta=1.55 meV, characteristic of clean, bulk Nb. However the tunneling density of states (DOS) was broadened significantly. The Nb pieces treated with the same mild baking used to improve the Q-slope in SRF cavities, reveal a sharper DOS. Good fits to the DOS were obtained using Shiba theory, suggesting that magnetic scattering of quasiparticles is the origin of the gapless surface superconductivity and a heretofore unrecognized contributor to the Q-slope problem of Nb SRF cavities.Comment: 3 pages, 3 figure

Measurements of Ultrasonic Scattering from Near-Surface Flaws

In ultrasonic NDE measurements the detection of subsurface flaws is of practical importance, especially flaws too far from the surface to be detected by eddy current methods and yet close enough to the surface for the flaw-surface interaction to be important. In this paper we report experimental results of ultrasonic scattering measurements of subsurface flaws in the presence of a fluid-solid interface and compare these results with theoretical calculations of subsurface flaw scattering. Comparison of the absolute value of the scattering amplitude in terms of frequency, flaw-to-surface distance, ultrasonic mode and scattering angle will be made for an oblate spheroidal void in the interior of bulk titanium and for a spherical inclusion near the surface of a thermoplastic sample. Results of applying the one-dimensional inverse Born algorithm to the sizing of near-surface flaws are also reported. This work was sponsored by the Center for Advanced Nondestructive Evaluation, operated by the Ames Laboratory, USDOE, for the Air Force Wright Aeronautical Laboratories/Materials Laboratory and the Defense Advanced Research Projects Agency under Contract No. W-7405-ENG-82 with Iowa State University

Metastatic Renal Cell Carcinoma to the Sinonasal Cavity: A Case Series

Objectives: To describe the presentation, work-up, and management of patients with metastatic renal cell carcinoma (RCC) to the sinonasal cavity and skull base, and to describe our current treatment algorithm of endoscopic surgical resection followed by radiation therapy. Design: Retrospective review of two recent cases from our institution over a 1-year period, with a relevant review of the literature. Setting: A large regional tertiary care facility. Participants: Consecutive cases of RCC with metastases to the sinonasal cavity presenting to our institution. Main Outcome Measures: Preoperative and postoperative sinonasal outcome test (SNOT)-22 scores, duration of hospital stay, complications, and local disease control Results: Patients in this series underwent preoperative embolization followed by endoscopic resection without complication. Postoperatively they were treated with radiation therapy. They experienced improvement in their SNOT-22 scores and are currently free of local disease. Conclusion: Metastatic RCC to the sinonasal cavity can be safely treated with preoperative embolization followed by endoscopic surgical resection and radiation therapy, which can result in improvement in sinonasal quality of life and is a potential adjunct for local control of disease

Weak localization in superconductors: A study of radiation-damaged Nb_3Ir

We have studied the critical temperature T_c, upper critical field, and magnetotransport variation as a function of radiation damage in the low-T_c A15 superconductor Nb_3Ir. We find a nonmonotonic variation in Tc with disorder and analyze these results in terms of the competition between density-of-states effects and weak localization. Magnetoresistance measurements confirm the presence of electron interaction effects associated with weak localization