Flight selection at United Airlines

Airline pilot selection proceedures are discussed including psychogical and personality tests, psychomotor performance requirements, and flight skills evaluation. Necessary attitude and personality traits are described and an outline of computer selection, testing, and training techniques is given

Two-Mirror Apodization for High-Contrast Imaging

Direct detection of extrasolar planets will require imaging systems capable of unprecedented contrast. Apodized pupils provide an attractive way to achieve such contrast but they are difficult, perhaps impossible, to manufacture to the required tolerance and they absorb about 90% of the light in order to create the apodization, which of course lengthens the exposure times needed for planet detection. A recently proposed alternative is to use two mirrors to accomplish the apodization. With such a system, no light is lost. In this paper, we provide a careful mathematical analysis, using one dimensional mirrors, of the on-axis and off-axis performance of such a two-mirror apodization system. There appear to be advantages and disadvantages to this approach. In addition to not losing any light, we show that the nonuniformity of the apodization implies an extra magnification of off-axis sources and thereby makes it possible to build a real system with about half the aperture that one would otherwise require or, equivalently, resolve planets at about half the angular separation as one can achieve with standard apodization. More specifically, ignoring pointing error and stellar disk size, a planet at $1.7 \lambda/D$ ought to be at the edge of detectability. However, we show that the non-zero size of a stellar disk pushes the threshold for high-contrast so that a planet must be at least $2.5 \lambda/D$ from its star to be detectable. The off-axis analysis of two-dimensional mirrors is left for future study.Comment: 21 pages, 7 figures. For author's webpage version see http://www.orfe.princeton.edu/~rvdb/tex/piaa/ms.pdf This version has improved figures and addresses comments of a refere

Measurement of H2O and other trace gases in the stratosphere using a high resolution far-infrared spectrometer at 28 km

Data analysis results from the 1983 BIC 1 and 2 balloon flights are presented, with emphasis on H2O2, OH, HCL, O3, O2, and H2O. A 2 sigma limit on H2O2 abundance was set, as a function of altitude. This is comparable to or less than the theoretically predicted winter abundances from the 2-D models of Dupont, with a large enough summer maximum to facilitate concentration profile measurements. There is a definite drop in OH concentration from day to night following two model profiles. There was general agreement between HF measurements. The dominant role of the far wings of H2O lines in low altitude spectra was recognized. The strength of these wings exceeds that of many molecular line cores, including O3 and O2, especially near the long wavelength end of the spectra (100 cm (-1)). Newly measured positions for O3 and H2O were obtained

Measurement of HO2 and other trace gases in the stratosphere using a high resolution far infrared spectrometer at 28 Km

A progress report and data analyses from the December 1980 flight are presented. The following areas are covered: (1) computer analysis of the flight spectra to obtain phase corrected, normalized sums of spectra for retrieval of atmospheric profiles; (2) study of atmospheric HF, HCl, and H2O; (3) stratospheric H2O2 and HOCl; (4) laboratory spectroscopy of HOCl; and (5) design study of a new balloon gondola. The majority of the flight data were taken in the low background mode, i.e., one input to the spectrometer looking at the sky and the other looking at a LN2 temperature blackbody. An analysis of HF stratospheric measurements was undertaken in conjunction with the HF analysis. High quality spectra showing the HOCl q-branches under optically thin conditions were also obtained

Effective Temperature Of Uranus

NASA NGR 09-015-047, NGR 22-007-270, NGR 44-012-152Astronom

Clinical investigations concerning the use of Ethrane for Cesarean section

Peer Reviewe

Atmospheric Biomarkers and their Evolution over Geological Timescales

The search for life on extrasolar planets is based on the assumption that one can screen extrasolar planets for habitability spectroscopically. The first space born instruments able to detect as well as characterize extrasolar planets, Darwin and terrestrial planet finder (TPF-I and TPF-C) are scheduled to launch before the end of the next decade. The composition of the planetary surface, atmosphere, and its temperature-pressure profile influence a detectable spectroscopic signal considerably. For future space-based missions it will be crucial to know this influence to interpret the observed signals and detect signatures of life in remotely observed atmospheres. We give an overview of biomarkers in the visible and IR range, corresponding to the TPF-C and TPF-I/DARWIN concepts, respectively. We also give an overview of the evolution of biomarkers over time and its implication for the search for life on extrasolar Earth-like planets. We show that atmospheric features on Earth can provide clues of biological activities for at least 2 billion years.Comment: for high resolution images see http://cfa-www.harvard.edu/~lkaltenegge