Color Variability of the Blazar AO 0235+16

Multicolor (UBVRIJHK) observations of the blazar AO 0235+16 are analyzed. The light curves were compiled at the Turin Observatory from literature data and the results of observations obtained in the framework of the WEBT program (http://www.to.astro/blazars/webt/). The color variability of the blazar was studied in eight time intervals with a sufficient number of multicolor optical observations; JHK data are available for only one of these. The spectral energy distribution (SED) of the variable component remained constant within each interval, but varied strongly from one interval to another. After correction for dust absorption, the SED can be represented by a power law in all cases, providing evidence for a synchrotron nature of the variable component. We show that the variability at both optical and IR wavelengths is associated with the same variable source.Comment: 11 pages, 9 figures, 4 tables, accepted for publication in Astronomy Report

De usu galvanismi in tractandis ulceribus syphiliticis : Dissertatio inauguralis quam consensu et auctoritate gratiosi medicorum ordinis in Universitate Literarum Caesarea Dorpatensi ad gradum doctoris medicinae. Rite adipiscendum loco consueto publice defendet

http://tartu.ester.ee/record=b1901126~S1*es

The Stellar Content of the Polar Rings in the Galaxies NGC 2685 and NGC 4650A

We present the results of stellar photometry of polar-ring galaxies NGC 2685 and NGC 4650A, using the archival data obtained with the Hubble Space Telescope's Wide Field Planetary Camera 2. Polar rings of these galaxies were resolved into ~800 and ~430 stellar objects in the B, V and Ic bands, considerable part of which are blue supergiants located in the young stellar complexes. The stellar features in the CM-diagrams are best represented by isochrones with metallicity Z = 0.008. The process of star formation in the polar rings of both galaxies was continuous and the age of the youngest detected stars is about 9 Myr for NGC 2685 and 6.5 Myr for NGC 4650A.Comment: 21 pages, 9 figures, AJ 2004 February, accepte

Clinical evaluation of a membrane-based voice-producing element for laryngectomized women

Background: A newly developed artificial voice source was clinically evaluated in laryngectomized women for voice quality improvements. The prosthesis was placed in a commercially available, tracheoesophageal shunt valve. - \ud Methods: In 17 subjects, voice-producing element (VPE) prototypes were compared with the subject's regular tracheo-esophageal shunt voice in a randomized cross-over trial. The evaluation was based on aeroacoustic measurements and perceptual analysis. - \ud Results: Considerably higher fundamental frequencies were attained with the use of the VPE. The sound pressure level also increased for most subjects. The required driving pressures of the lung and air flow rates were altered, allowing significantly longer phonation times in 1 breath. Accumulation of mucus did not interfere with the proper functioning of the device during these tests. - \ud Conclusion: A VPE with sound-generating membranes is suitable for providing a substitute voice source for laryngectomized patients, especially patients suggestive of a severely hypotonic or atonic pharyngoesophageal segment who can benefit from a more melodious and louder voice

In vitro evaluation of a double-membrane-based voice-producing element for laryngectomized patients

Background: A sound generator based on a double-membrane design that fits into a regular tracheoesophageal shunt valve may improve voice quality after total laryngectomy in patients rehabilitated with surgical voice prostheses. - Methods: Voice-producing element (VPE) prototypes were manufactured using medical grade biocompatible materials and tested in vitro under physiological conditions. - Results: Basic sound, containing multiple harmonics, was successfully produced under physiologic air pressure and airflow conditions. The fundamental frequency and sound pressure level (SPL) is controlled by changing the driving pressure, thus enabling sufficient intonation for day-to-day speech. The obtained frequency range (190-350 Hz) is appropriate for producing a female voice. The low noise-to-harmonics ratio (mean 0.15) and also the efficiency of sound production (5.5 × 10-5 at 80 dB(A) and 0.15 m microphone distance) is comparable to that of normal vocal folds. - Conclusions: Functional restoration of the voice after laryngectomy with a double-membrane VPE appears to be a feasible concept for female laryngectomized patients with a hypotonic, or atonic pharyngoesophageal segment