1,530 research outputs found
Imaging studies of comets
Schmidt camera plates of comet Bradfield were secured on several nights in October 1987. The images of October 20 show the development of a huge bend in the plasma tail travelling several hundred kilometers per second down the tail; the likely solar-wind origin of this event is being explored. A charged coupled device (CCD) detector has been obtained. Calibration of the CCD is still underway, but high-quality, filtered cometary images shoud be possible in the near future
Predation by Amphibians and Small Mammals on the Spruce Budworm (Lepidoptera: Tortricidae)
Stomach-content analyses of pitfall-trapped amphibians and small mammals showed that the eastern American toad, Bujo americanus americanus, and the wood frog, Rana sylvatica, preyed on late instars and moths of the spruce budworm, Choristoneura fumiferana. The spotted salamander, Ambystoma maculatum, and the masked shrew, Sorex cinereus, also preyed on late instars of the spruce budworm
Large-scale interaction of the solar wind with comets Halley and Giacobini-Zinner
In-situ measurements of comets Halley and Giacobini-Zinner have confirmed the accepted basic physics of comet/solar wind interaction. The solar wind magnetic field is captured by the comet through the mechanism of field-line loading by cometary ions and the field lines drape around the cometary ionosphere. With this basic model in hand, the large-scale structure of the plasma tail as revealed by submissions to the Large Scale Phenomena Network of the International Halley Watch is reviewed. The turn-on and turn-off of plasma activity seem consistent with theory. Some 16 obvious disconnection events (DEs) have been recorded. Preliminary results showed agreement with the sector-boundary model; a detailed analysis of all DEs will be required in order to make a definitive statement. A study of plasma activity around the time of the VEGA encounters provides strong support for the sector-boundary model and illustrates once again the power of simultaneous remote and in-situ measurements
From Cold War to Microchips: Stepping From the Past into Our Future
Malcolm Steve Forbes Jr., editor-in-chief of FORBES Magazine, looks often to history to explain the present and to predict the future. In an address to the 21st annual Governor\u27s Economic Development Conference at the University of Maine last fall, Forbes identified two important trends, one grounded in the past (the Cold War), and one symbolic of the rapid change experienced at present (the microchip), in suggesting that the economic future for Maine and the nation is only limited by our willingness to give in to our fears about what that future holds. This article is an edited version of Forbes’ remarks to the Governor\u27s Conference
From Cold War to Microchips: Stepping From the Past into Our Future
Malcolm Steve Forbes Jr., editor-in-chief of FORBES Magazine, looks often to history to explain the present and to predict the future. In an address to the 21st annual Governor\u27s Economic Development Conference at the University of Maine last fall, Forbes identified two important trends, one grounded in the past (the Cold War), and one symbolic of the rapid change experienced at present (the microchip), in suggesting that the economic future for Maine and the nation is only limited by our willingness to give in to our fears about what that future holds. This article is an edited version of Forbes’ remarks to the Governor\u27s Conference
Collaborative Research: Land-Use Practices And Persistence Of Amphibian Populations
Over the past 200 years, conversion of land for agricultural use, industrial development, and urban sprawl has drastically reduced natural habitat for many species and is considered the most serious threat to biological diversity. Fragmentation divides once continuous natural habitats into smaller pieces that are often separated by areas unsuitable to sustain viable populations. The goal of the proposed research is to understand how important local population and metapopulation processes are altered by fragmentation of natural habitats in a model system of pond-breeding amphibians. The primary objectives of the proposed study are to experimentally compare demographic and behavioral responses of amphibians in clear-cut (with and without coarse woody debris), partial-cut, edge, and intact forest habitats around replicated natural breeding ponds. These results will lead to a better understanding of the habitat requirements for successful recruitment and survival of local populations, and how amphibians disperse through fragmented landscapes. It will allow strong inferences about the disruption of metapopulation dynamics in amphibians caused by fragmentation and about how to prevent population declines and extinctions. Further, information from this project is essential to the development of conservation and management plans in state natural resource agencies, the U.S.D.A. Forest Service, and the Bureau of Land Management
Collaborative Research: Land-Use Practices And Persistence Of Amphibian Populations.
Over the past 200 years, conversion of land for agricultural use, industrial development, and urban sprawl has drastically reduced natural habitat for many species and is considered the most serious threat to biological diversity. Fragmentation divides once continuous natural habitats into smaller pieces that are often separated by areas unsuitable to sustain viable populations. The goal of the proposed research is to understand how important local population and metapopulation processes are altered by fragmentation of natural habitats in a model system of pond-breeding amphibians. The primary objectives of the proposed study are to experimentally compare demographic and behavioral responses of amphibians in clear-cut (with and without coarse woody debris), partial-cut, edge, and intact forest habitats around replicated natural breeding ponds. These results will lead to a better understanding of the habitat requirements for successful recruitment and survival of local populations, and how amphibians disperse through fragmented landscapes. It will allow strong inferences about the disruption of metapopulation dynamics in amphibians caused by fragmentation and about how to prevent population declines and extinctions. Further, information from this project is essential to the development of conservation and management plans in state natural resource agencies, the U.S.D.A. Forest Service, and the Bureau of Land Management
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