1,295 research outputs found

    Analysis of terrestrial conditions and dynamics

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    Land spectral reflectance properties for selected locations, including the Goddard Space Flight Center, the Wallops Flight Facility, a MLA test site in Cambridge, Maryland, and an acid test site in Burlington, Vermont, were measured. Methods to simulate the bidirectional reflectance properties of vegetated landscapes and a data base for spatial resolution were developed. North American vegetation patterns observed with the Advanced Very High Resolution Radiometer were assessed. Data and methods needed to model large-scale vegetation activity with remotely sensed observations and climate data were compiled

    Shortwave infrared detection of vegetation

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    The potential of short wave infrared (SWIR) measurements in vegetation discrimination is further substantiated through a discussion of field studies and an examination of the physical bases which cause SWIR measurements to vary with the vegetation type observed. The research reported herein supported the AGRISTARS program objective to incorporate TM measurements in the analysis of agricultural activity. Field measurements on corn and soybeans in Iowa were conducted, and the mean and variance of canopy reflectance were computed for each observation date. The Suits canopy reflectance model was used to evaluate possible explanations of the observed corn/soybeans reflectance patterns /39/. The SWIR measurements were shown to effectively discriminate corn and soybeans on the basis of leaf absorption properties

    Analysis of the boreal forest-tundra ecotone: A test of AVIRIS capabilities in the Eastern Canadian subarctic

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    A comparison was conducted between ground reflectance spectra collected in Schefferville, Canada and imaging spectrometer observations acquired by the AVIRIS sensor in a flight of the ER-2 Aircraft over the same region. The high spectral contrasts present in the Canadian Subarctic appeared to provide an effective test of the operational readiness of the AVIRIS sensor. Previous studies show that in this location various land cover materials possess a wide variety of visible/near infrared reflectance properties. Thus, this landscape served as an excellent test for the sensing variabilities of the newly developed AVIRIS sensor. An underlying hypothesis was that the unique visible/near infrared spectral reflectance patterns of Subarctic lichens could be detected from high altitudes by this advanced imaging spectrometer. The relation between lichen occurrence and boreal forest-tundra ecotone dynamics was investigated

    Aboriginal Glass Artefacts of the Sydney Region

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    Aboriginal glass artefacts (AGAs) have become the ‘type fossil’ for recognizing post-contact sites in countries with colonial pasts. Whether such reliance on AGAs is a valid development is contentious as the identification of these artefacts is ambiguous. This uncertainty is amplified in densely populated urban environments such as Sydney. This thesis addresses the identification of these artefacts within this region. Technological characteristics of Sydney’s AGAs and methodological issues in the recording of these artefacts have been analysed. A review of the patterns within this data has revealed how the identification issue has been managed in the past and how it may be improved. A review and evaluation of previous ‘criteria for identification’ has also revealed a refined approach to the identification and categorization of AGAs within Sydney and beyond. Also, cross-cultural interactions have been characterized as affected by the unique and diverse nature of the moving frontier in this region

    I Spy Through a Camera’s Eye: Divii in the Gwich’in Settlement Area

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    Gender and journalism

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    The media is an important cultural gatekeeper, but not a disinterested one. Inevitably journalists, their interests, backgrounds, intellectual capacity and prejudices shape what they consider we need to know. Even unconsciously they filter what they want us to know about ourselves, each other and the world. This makes the media a major vehicle, although curiously not the only vehicle, for the shaping of public opinion and in particular for the management of our responses to change. The media is also one of four so-called pillars of democracy, ensuring electors are able to make informed choices as well as engage in public policy debate. Accordingly an effective media represents a diversity ogf opinion and a range of interests which include the rights and interests and real lives of women as well as the contribution they make to the life of the nation. That's why gender counts in journalism. It is part of diversity.&nbsp

    Monitoring recovery of overgrazed lichen communities on Hagemeister Island, southwestern Alaska

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    Understanding the recovery rate of overgrazed lichen communities has value to mangers of lands in northern regions.  We describe lichen community composition and present recovery rate measurements for a 12-year period following overgrazing by reindeer (Rangifer tarandus) on Hagemeister Island, Alaska.  Reindeer were removed from the island in 1993 following overgrazing and average total lichen biomass increased from 504.2 kg/ha (SD 205.4) in 2003 to 795.3 (SD 489.6) in 2015.  We estimate time to recovery with three competing growth curves which estimate grazeable biomass may be reached in 34-41 years.  However, estimates of full recovery to climax biomass varied among the models, ranging from 71 to 400 years.   In 2015, lichen communities were composed of various mixtures of at least 78 lichen taxa, and were dominated by Cladina stygia and other important reindeer forage species.   While reindeer overgrazing diminished forage quantity, it did not extirpate preferred forage taxa. &nbsp

    Gowardia zebrina sp. nov., a new species in a little-known genus of arctic-alpine lichens (Parmeliaceae)

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    The fruticose lichen genus Gowardia (Parmeliaceae) was recently segregated from Alectoria based on phylogeny, morphology, secondary chemistry, ecology and distribution. As currently circumscribed, Gowardia comprises two wide-ranging species of arctic-alpine regions. Here we describe a third species, G. zebrina sp. nov., apparently endemic to subalpine regions in mountainous northwestern North America. Gowardia zebrina differs from other species in the genus by its combined subpendent habit, uniformly capillary branches, predominantly isotomic branching, pale-and-dark banding of the terminal branches, and epiphytic ecology. Morphological examination of North American herbarium specimens filed under A. nigricans suggests the existence of several additional undescribed species of Gowardia. A brief overview of morphological diversity in these species is given, shedding new light on the question of whether Gowardia should be subsumed under Alectoria, as some have suggested, or is more appropriately recognized as a distinct genus.Peer reviewe
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