118,162 research outputs found
Computer analysis and mapping of gypsy moth levels in Pennsylvania using LANDSAT-1 digital data
The effectiveness of using LANDSAT-1 multispectral digital data and imagery, supplemented by ground truth and aerial photography, was investigated as a new method of surveying gypsy moth (Porthetria dispar (L.)) (Lepidoptera; Lymantriidae) defoliation, which has greatly increased in Pennsylvania in recent years. Since the acreage and severity of gypsy moth defoliation reaches a peak from mid-June through the first few days of July, the July 8, 1973, LANDSAT-1 scene was chosen for analysis. Results indicate that LANDSAT-1 data can be used to discriminate between defoliated and healthy vegetation in Pennsylvania and that digital processing methods can be used to map the extent and degree of defoliation
A canopy-related stratification of a southern pine forest using LANDSAT digital data
An investigation was undertaken to determine if a consistent stratification of a Southern pine forest could be obtained by using LANDSAT multispectral scanner data to assess crown closure. Winter and summer LANDSAT scenes of the North Carolina coastal region were analyzed individually and then registered and merged to take advantage of temporal changes in the forest canopy. Three levels of pine crown closure were accurately delineated. The applicability of this stratification as supplemental input to a forest inventory system is also discussed
Monitoring forest canopy alteration around the world with digital analysis of LANDSAT imagery
There are no author-identified significant results in this report
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Monopoly rents and price fixing in betting markets
Betting markets provide an ideal environment in which to examine monopoly power due to the availability of detailed information on product pricing. In this paper we argue that the pricing strategies of companies in the UK betting industry are likely to be an important source of monopoly rents, particularly in the market for forecast bets. Pricing in these markets are shown to be explicitly coordinated. Further, price information is asymmetrically biased in favor of producers. We find evidence, based on UK data, that pricing of CSF bets is characterized by a significantly higher markup than pricing of single bets. Although this differential can in part be explained by the preferences of bettors, it is reasonable to attribute a significant part of the differential as being due to monopoly power
High energy density electrochemical cell
Primary cell has an anode of lithium, a cathode containing dihaloisocyanuric acid, and a nonaqueous electrolyte comprised of a solution of lithium perchlorate in methyl formate. It produces an energy density of 213 watt hrs/lb and can achieve a high current density
Limits on the Halo White Dwarf Component of Baryonic Dark Matter from the {\em Hubble Deep Field}
The MACHO collaboration lensing event statistics suggest that a significant
fraction of the dark galactic halo can be comprised of baryonic matter in the
form of white dwarf stars with masses between 0.1 and 1.0 \Msun . Such a halo
white dwarf population, in order to have escaped detection by those who observe
the white dwarf luminosity function of the disk, must have formed from an old
population. The observations indicate that the number of halo white dwarfs per
cubic parsec per unit bolometric magnitude is less than at
\Lsun; the number must rise significantly at lower luminosities to
provide the needed baryonic halo mass. Such white dwarfs may easily escape
detection in most current and earlier surveys. Though it is limited in angular
extent, the {\em Hubble Deep Field} (HDF) probes a sufficient volume of the
galactic halo to provide interesting limits on the number of halo white dwarf
stars, and on the fraction of the halo mass that they can make up. If the HDF
field can be probed for stars down to then the MACHO result suggests
that there could be up to 12 faint halo white dwarfs visible in the HDF.
Finding (or not finding) these stars in turn places interesting constraints on
star formation immediately following the formation of the galaxy.Comment: 10 pages, AASTEX, 1 table, no figures, accepted for publication in
Ap.J. Letter
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A policy response to the e-commerce revolution: the case of betting taxation in the UK
Several environmental changes in the 1990s – including the introduction of a national lottery, the rise of Internet gambling, and the reduction of trade barriers within the EU – induced the UK government to initiate a large-scale review of betting duty. As a result of this review, the government recently announced a significant reduction in betting taxes. They also decided to replace the current general betting duty (GBD), levied as a proportion of betting stakes, with a gross profits tax (GPT), based on the net revenue of bookmakers. We examine the economic rationale behind these decisions and demonstrate how these tax changes have broad implications regarding optimal levels of taxation for other sources of government revenue
A Bayesian method for detecting stellar flares
We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares
in light curve data. We assume flares are described by a model in which there
is a rapid rise with a half-Gaussian profile, followed by an exponential decay.
Our signal model also contains a polynomial background model. This is required
to fit underlying light curve variations that are expected in the data, which
could otherwise partially mimic a flare. We characterise the false alarm
probability and efficiency of this method and compare it with a simpler
thresholding method based on that used in Walkowicz et al (2011). We find our
method has a significant increase in detection efficiency for low
signal-to-noise ratio (S/N) flares. For a conservative false alarm probability
our method can detect 95% of flares with S/N less than ~20, as compared to S/N
of ~25 for the simpler method. As an example we have applied our method to a
selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars
with a total of 1873 flares after vetos have been applied. For these flares we
have characterised their durations and and signal-to-noise ratios.Comment: Accepted for MNRAS. The code used for the analysis can be found at
https://github.com/BayesFlare/bayesflare/releases/tag/v1.0.
Development of the dry tape battery concept Quarterly report no. 4, 9 Mar. - 9 Jun. 1966
Aqueous and nonqueous electrolytic actions, and energy density measurements for dry tape batter
Utilization of LANDSAT imagery for mapping vegetation on the millionth scale
A series of test sites were examined to determine if the information content of the LANDSAT imagery that may be obtained of these sites is sufficient to permit their mapping according to the vegetation classification system recently published by Unesco. These sites include examples from the humid tropics, arid and semi-arid subtropics and temperature zones: Western Highlands of Papua New Guinea, Mindoro Island in the Philippines, Great Smoky Mountains of the southeastern United States, East Tennessee Valley, interior of Western Australia, northeastern Uganda, and south-central Kansas. The results of the experiment were presented in the form of vegetation maps and annotated images which serve to illustrate the detectability of various formations. It was concluded that, for the test sites examined, the formations of the Unesco vegetation classification can be satisfactorily distinguished on LANDSAT MSS images, especially when used as color composites and judiciously chosen as to season
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