14,968 research outputs found
Size and Age Records for an Arkansas Specimen of the American Bullfrog, Lithobates catesbeianus (Anura: Ranidae)
Financial Market Runs
Our paper offers a minimalist model of a run on a financial market. The prime ingredient is that each risk-neutral investor fears having to liquidate after a run, but before prices can recover back to fundamental values. During the urn, only the risk-averse market-making sector is willing to absorb shares. To avoid having to possibly liquidate shares at the marginal post-run price in which case the market-making sector will already hold a lot of share inventory and thus be more reluctant to absorb additional shares all investors may prefer selling their shares into the market today at the average run price, thereby causing the run itself. Consequently, stock prices are low and risk is allocated inefficiently. Liquidity runs and crises are not caused by liquidity shocks per se, but by the fear of future liquidity shocks.
Geometric accuracy of LANDSAT-4 MSS image data
Analyses of the LANDSAT-4 MSS image data of North Georgia provided by the EDC in CCT-p formats reveal that errors of approximately + or - 30 m in the raw data can be reduced to about + or - 55 m based on rectification procedures involving the use of 20 to 30 well-distributed GCPs and 2nd or 3rd degree polynomial equations. Higher order polynomials do not appear to improve the rectification accuracy. A subscene area of 256 x 256 pixels was rectified with a 1st degree polynomial to yield an RMSE sub xy value of + or - 40 m, indicating that USGS 1:24,000 scale quadrangle-sized areas of LANDSAT-4 data can be fitted to a map base with relatively few control points and simple equations. The errors in the rectification process are caused by the spatial resolution of the MSS data, by errors in the maps and GCP digitizing process, and by displacements caused by terrain relief. Overall, due to the improved pointing and attitude control of the spacecraft, the geometric quality of the LANDSAT-4 MSS data appears much improved over that of LANDSATS -1, -2 and -3
On the Evolution of Overconfidence and Entrepreneurs
This paper explains why seemingly irrational overconfident behavior can persist. Information aggregation is poor in groups in which most individuals herd. By ignoring the herd, the actions of overconfident individuals ("entrepreneurs") convey their private information. However, entrepreneurs make mistakes and thus die more frequently. The socially optimal proportion of entrepreneurs trades off the positive information externality against high attrition rates of entrepreneurs, and depends on the size of the group, on the degree of overconfidence, and on the accuracy of individuals' private information. The stationary distribution trades off the fitness of the group against the fitness of overconfident individuals.Evolution, overconfidence, behavioral economics
An interregional analysis of natural vegetation analogues using ERTS-1 imagery
The identification of ecological analogs of natural vegetation and food crops using ERTS-1 imagery is discussed. Signatures of four natural vegetation analogs have been determined from color photography. Color additive techniques to improve the photointerpretation are examined. Tests were conducted at test sites in Louisiana, California, and Colorado
Plan for the uniform mapping of earth resources and environmental complexes from Skylab imagery. Assessment of natural vegetation, environmental, and crop analogs
The author has identified the following significant results. For interpreting a wide range of natural vegetation analogs, S-190A color infrared and the ERTS-1 color composite were consistently more useful than were conventional color or black and white photos. Color infrared was superior for five vegetation analogs while color was superior for only three. The errors in identification appeared to associate more with black and white single band images than with multiband color. For rice crop analogs, spectral and spatial discriminations both contribute to the usefulness of images for data collection. Tests and subjective analyses conducted in this study indicated that the spectral bands exploited in color infrared film were the most useful for agricultural crop analysis. Accuracy of crop identification on any single date of Skylab images was less than that of multidate analysis due to differences in crop calendar, cultural practices used, rice variety, planting date, planting method, water use, fertilization, disease, or mechanical problems
Group velocity study in hot Rb vapor with buffer gas
We study the behavior of the group velocity of light under conditions of
electromagnetically induced transparency (EIT) in a Doppler broadened medium.
Specifically, we show how the group delay (or group velocity) of probe and
generated Stokes fields depends on the one-photon detuning of drive and probe
fields. We find that for atoms in a buffer gas the group velocity decreases
with positive one-photon detuning of the drive fields, and increases when the
fields are red detuned. This dependence is counter-intuitive to what would be
expected if the one-photon detuning resulted in an interaction of the light
with the resonant velocity subgroup.Comment: 6 pages, 7 figure
Anaesthetic genetics and genomics
Genetic variations have always been implicated in interindividual reactions to various pharmaceutical agents. Some common genetically determined anaesthetic conditions, such as malignant hyperthermia, “scoline apnoea”, “halothane hepatitis” and porphyria, are fairly well described, and the genetic differences in enzyme, receptor and ion channel systems are slowly being elucidated. These genomic differences allow some explanation as to why drugs that work well in certain patients produce no or unwanted effects in others.Keywords: anaesthetic genetics, genomics, malignant hyperthermia, porphyri
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