2,021 research outputs found
SAO/NASA joint investigation of astronomical viewing quality at Mount Hopkins Observatory: 1969-1971
Quantitative measurements of the astronomical seeing conditions have been made with a stellar-image monitor system at the Mt. Hopkins Observatory in Arizona. The results of this joint SAO-NASA experiment indicate that for a 15-cm-diameter telescope, image motion is typically 1 arcsec or less and that intensity fluctuations due to scintillation have a coefficient of irradiance variance of less than 0.12 on the average. Correlations between seeing quality and local meteorological conditions were investigated. Local temperature fluctuations and temperature gradients were found to be indicators of image-motion conditions, while high-altitude-wind conditions were shown to be somewhat correlated with scintillation-spectrum bandwidth. The theoretical basis for the relationship of atmospheric turbulence to optical effects is discussed in some detail, along with a description of the equipment used in the experiment. General site-testing comments and applications of the seeing-test results are also included
Interviewing and Counseling Clients in a Legal Setting
The purpose of this article is to point out some of the factors that, in the experience of the authors, contribute to the success, or lack of success, of an interview and to help the attorney discover the source of any difficulties which s/he may have so that the impact of factors leading to unsatisfactory encounters with clients may be reduced or eliminated
Competitive Effect on the Rate of the Diffusion-Controlled Reaction A+B→C
None available; appears in letters section
A meteorological report for the Mt. Hopkins Observatory: 1968-1971
This document is a compilation of the weather data collected at the Mt. Hopkins Observatory in southern Arizona from 1968 to 1971. It is the second meteorological report aimed at assisting scientists in the scheduling of experiments at the Observatory site
Endometrioma Complicated by Tubo-Ovarian Abscess in a Woman With Bacterial Vaginosis
Background. Tubo-ovarian abscess involvement of an endometrioma has been reported in cases of patients with polymicrobial sources such as Neisseria gonorrhoeae, Chlamydia trachomatis, and obligate anaerobic bacteria; however, bacterial vaginosis (BV) predisposing to abscess formation in an endometrioma has not been reported to date. Case. Superinfection of an endometrioma was surgically diagnosed in a patient with known advanced-stage endometriosis after she presented with acute pelvic inflammatory disease symptoms and was unresponsive to antibiotic therapy. Gram-negative rods were cultured from the endometrioma. On admission, cervical, blood, and urine cultures were negative; BV was diagnosed on normal saline wet prep and gram stain. Conclusion. This case raises the possibility of BV ascension to the upper genital tract predisposing to abscess formation in endometriomas. Therefore, aggressive treatment of BV in patients with known advanced-stage endometriosis may be considered to prevent superinfected endometriomas
Parametrization of the Hybrid Potential for Pairs of Neutral Atoms
The hybrid form is a combination of the Rydberg potential and the London
inverse-sixth-power energy. It is accurate at all relevant distance scales and
simple enough for use in all-atom simulations of biomolecules. One may compute
the parameters of the hybrid potential for the ground state of a pair of
neutral atoms from their internuclear separation, the depth and curvature of
their potential at its minimum, and from their van der Waals coefficient of
dispersion.Comment: 7 pages, 11 figures, includes lithium, sodium, & potassium dimers,
minor correction
Infrared Imaging of Capella with the IOTA Closure Phase Interferometer
We present infrared aperture synthesis maps produced with the upgraded IOTA
interferometer. Michelson interferograms on the close binary system Capella
(Alpha Aur) were obtained in the H-band between 2002 November 12 and 16 using
the IONIC3 beam combiner. With baselines of 15m < B < 38m, we were able to
determine the relative position of the binary components with milliarcsecond
(mas) precision and to track their movement along the approx. 14 degree arc
covered by our observation run. We briefly describe the algorithms used for
visibility and closure phase estimation. Three different Hybrid Mapping and
Bispectrum Fitting techniques were implemented within one software framework
and used to reconstruct the source brightness distribution. By dividing our
data into subsets, the system could be mapped at three epochs, revealing the
motion of the stars. The precise position of the binary components was also
determined with model fits, which in addition revealed I_Aa/I_Ab=1.49 +/- 0.10
and apparent stellar uniform-disk (UD) diameters of Theta_Aa=8.9 +/- 0.6 mas
and Theta_Ab=5.8 +/- 0.8 mas.
To improve the u, v-plane coverage, we compensated this orbital motion by
applying a rotation-compensating coordinate transformation. The resulting
model-independent map with a beam size of 5.4 x 2.6 mas allows the resolution
of the stellar surfaces of the Capella giants themselves.Comment: Accepted by the Astronomical Journal (2005-03-21
Bright Localized Near-Infrared Emission at 1-4 AU in the AB Aurigae Disk Revealed by IOTA Closure Phases
We report on the detection of localized off-center emission at 1-4 AU in the
circumstellar environment of the young stellar object AB Aurigae. We used
closure phase measurements in the near-infrared made at the long baseline
interferometer IOTA, the first obtained on a young stellar object using this
technique. When probing sub-AU scales, all closure phases are close to zero
degrees, as expected given the previously-determined size of the AB Aurigae
inner dust disk. However, a clear closure phase signal of -3.5 +/- 0.5 degrees
is detected on one triangle containing relatively short baselines, requiring a
high degree of non-point symmetry from emission at larger (AU-sized) scales in
the disk. We have not identified any alternative explanation for these closure
phase results and demonstrate that a ``disk hot spot'' model can fit our data.
We speculate that such asymmetric near-infrared emission detected might arise
as a result of localized viscous heating due to a gravitational instability in
the AB Aurigae disk, or to the presence of a close stellar companion or
accreting sub-stellar object.Comment: Accepted by Astrophysical Journal Letter
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