17,901 research outputs found
Study of lunar earthshine by photoelectric photometry Final report, 1 Nov. 1965 - 30 Sep. 1967
Design feasibility and performance of semiportable field instrument for monitoring changes in earth albedo via earthshine measurement
Conceptual model of salt marsh management on Merritt Island National Wildlife Refuge, Florida: final report
Diking and holding water on salt marshes ("impounding" the marsh) is a
management technique used on Merritt Island National Wildlife Refuge
(MINWR) and elsewhere in the Southeast to: a) prevent the reproduction of
saltmarsh mosquitos, and b) attract wintertering waterfowl and other marsh,
shore, and wading birds. Because of concern that diking and holding water
may interfere with the production of estuarine fish and shellfish,
impoundment managers are being asked to consider altering management
protocol to reduce or eliminate any such negative influence. How to change
protocol and preserve effective mosquito control and wildlife management is
a decision of great complexity because: a) the relationships between
estuarine organisms and the fringing salt marshes at the land-water interface
are complex, and b) impounded marshes are currently good habitat for a
variety of species of fish and wildlife. Most data collection by scientists
and managers in the area has not been focused on this particular
problem. Furthermore, collection of needed data may not be possible before
changes in protocol are demanded. Therefore, the purpose of this document
is two-fold: 1) to suggest management alternatives, given existing information,
and 2) to help identify research needs that have a high probability
of leading to improved simultaneous management of mosquitos, waterfowl,
other wildlife, freshwater fish, and estuarine fish and shellfish on the
marshland of the Merritt Island National Wildlife Refuge. (92 page document
Categorized bibliography for a conceptual model of salt marsh management on Merritt Island, Florida
Enclosed is a bibliography of 556 published articles,
technical reports, theses, dissertations, and books that form the
basis for a conceptual model of salt marsh management on Merritt
Island, Florida (Section 1). A copy of each item is available on
file at the Florida Cooperative Fish and Wildlife Research Unit,
Gainesville. Some relevant proprietary items and unpublished
drafts have not been included pending permission of the authors.
We will continue to add pertinent references to our bibliography
and files. Currently, some topics are represented by very few
items. As our synthesis develops, we will be able to indicate a
subset of papers most pertinent to an understanding of the
ecology and management of Merritt Island salt marshes.
(98 page document
FOCIS: A forest classification and inventory system using LANDSAT and digital terrain data
Accurate, cost-effective stratification of forest vegetation and timber inventory is the primary goal of a Forest Classification and Inventory System (FOCIS). Conventional timber stratification using photointerpretation can be time-consuming, costly, and inconsistent from analyst to analyst. FOCIS was designed to overcome these problems by using machine processing techniques to extract and process tonal, textural, and terrain information from registered LANDSAT multispectral and digital terrain data. Comparison of samples from timber strata identified by conventional procedures showed that both have about the same potential to reduce the variance of timber volume estimates over simple random sampling
Self-stimulated Emission of Undulator Radiation
We attract attention that interaction of particle in downstream undulator
with its own wavelet emitted in upstream undulator could be as strong as with
the frictional field in undulator itself. This phenomenon could be used for
enhancement of signal from pickup undulators in optical stochastic cooling
methods as well as for increase of damping.Comment: 3 pages, 2 figure
Two-region model for positive and negative plasma sheaths and its application to Hall thruster metallic anodes.
An asymptotic presheath/sheath model for positive and negative sheaths in front of a conducting electrode, with a continuous parametric transition at the no-sheath case, is presented. Key aspects of the model are as follows: full hydrodynamics of both species in the presheath; a kinetic formulation with a truncated distribution function for the repelled species within the sheath; and the fulfillment of the marginal Bohm condition at the sheath edge, in order to match the two formulations of the repelled species. The sheath regime depends on the ratios of particle fluxes and sound speeds between the two species. The presheath model includes the effect of a magnetic field parallel to the wall on electrons. An asymptotic, parametric study of the anode presheath is carried out in terms of the local ion-to-electron flux ratio and Hall parameter. The drift-diffusive model of magnetized electrons fails in a parametric region that includes parts of the negative sheath regime. In the case of the Hall parameter vanishing near the electrode and a weakly collisional plasma, a quasisonic, quasineutral plateau forms next to the sheath edge
Classical Fault Analysis of MOS VLSI Circuits
Due to the large cost involved in generating effective input vectors to test MOS circuits, finding ways to reduce this test vector generation cost is of considerable interest. In this paper, empirical results show the fault coverage obtained form MOS transistor-level fault simulation using randomly generated test inputs can be approximated by the fault coverage obtained using the test vectors generated from classical stuck-at-zero and stuck-at-one fault simulation on logic-gate-level circuits. Applying this results, an approach is presented to reduce the cost of test vector generation for MOS circuits
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