33,794 research outputs found
Growth vs. margins: destabilizing consequences of giving the stock market what it wants
We develop a multi-tasking model in which a firm can devote its efforts either to increasing sales growth, or to improving per-unit profit margins by, e.g., cutting costs. If the firm's manager is concerned with the current stock price, she will tend to favor the growth strategy at those times when the stock market is paying more attention to performance on the growth dimension. Conversely, it can be rational for the stock market to weight observed growth measures more heavily when it is known that the firm is following a growth strategy. This two-way feedback between firms' business strategies and the market's pricing rule can lead to purely intrinsic fluctuations in sales and output, creating excess volatility in these real variables even in the absence of any external source of shocks
Kinematics of the southern galaxy cluster Abell 3733
We report radial velocities for 99 galaxies with projected positions within
30 arcmin of the center of the cluster A3733 obtained with the MEFOS multifiber
spectrograph at the 3.6-m ESO telescope. These measurements are combined with
39 redshifts previously published by Stein (1996) to built a collection of 112
galaxy redshifts in the field of A3733, which is used to examine the kinematics
and structure of this cluster. We assign cluster membership to 74 galaxies with
heliocentric velocities in the interval 10500-13000 km/s. From this sample of
cluster members, we infer a heliocentric systemic velocity for A3733 of
11653{+74}{-76} km/s, which implies a mean cosmological redshift of 0.0380, and
a velocity dispersion of 614{+42}{-30} km/s. The application of statistical
substructure tests to a magnitude-limited subset of the latter sample reveals
evidence of non-Gaussianity in the distribution of ordered velocities in the
form of lighter tails and possible multimodality. Spatial substructure tests do
not find, however, any significant clumpiness in the plane of the sky, although
the existence of subclustering along the line-of-sight cannot be excluded.Comment: AA-LaTeX2e style; 10 pages, 2 Postscript figures, Table 1 appended.
To be published in Astronomy and Astrophysics. Also available at
ftp://pcess1.am.ub.es/pub/AA/a3733.ps.g
Indiana Ensifera (Orthopera)
(excerpt)
A total of 67 species of long-horned grasshoppers and crickets were reported to occur in Indiana by Blatchley (1903) in his Orthoptera of Indiana. Distributional information concerning thek species was sparse and has not been significantly supplemented since that time. Subsequent works which have dealt either heavily or exclusively with the Indiana fauna include Fox (1915), Blatchley (1920), Cantrall and Young (1954), and Young and Cantrall(1956)
Asymptotic Eigenstructures
The behavior of the closed loop eigenstructure of a linear system with output feedback is analyzed as a single parameter multiplying the feedback gain is varied. An algorithm is presented that computes the asymptotically infinite eigenstructure, and it is shown how a system with high gain, feedback decouples into single input, single output systems. Then a synthesis algorithm is presented which uses full state feedback to achieve a desired asymptotic eigenstructure
Construction and Characterization of a Frequency-Controlled, Picometer-Resolution, Displacement Encoder-Actuator
We have constructed an actuator/encoder whose generated displacement is
controlled through the resonance frequency of a microwave cavity. A compact,
10-micrometer-range, digitally-controlled actuator executing frequency-coded
displacement with picometer resolution is described. We consider this approach
particularly suitable for metrologic-precision scanning probe microscopy.Comment: 4 pages, 4 figure
Radon gas, useful for medical purposes, safely fixed in quartz
Radon gas is enclosed in quartz or glass ampules by subjecting the gas sealed at a low pressure in the ampules to an ionization process. This process is useful for preparing fixed radon sources for radiological treatment of malignancies, without the danger of releasing radioactive gases
Longwall shearer tracking system
A tracking system for measuring and recording the movements of a longwall shearer vehicle includes an optical tracking assembly carried at one end of a desired vehicle path and a retroreflector assembly carried by the vehicle. Continuous horizontal and vertical light beams are alternately transmitted by means of a rotating Dove prism to the reflector assembly. A vertically reciprocating reflector interrupts the continuous light beams and converts these to discrete horizontal and vertical light beam images transmitted at spaced intervals along the path. A second rotating Dove prism rotates the vertical images to convert them to a second series of horizontal images while the first mentioned horizontal images are left unrotated and horizontal. The images are recorded on a film
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