6,642 research outputs found

    Proceedings of the Second Airborne Imaging Spectrometer Data Analysis Workshop

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    Topics addressed include: calibration, the atmosphere, data problems and techniques, geological research, and botanical and geobotanical research

    Proceedings of the Airborne Imaging Spectrometer Data Analysis Workshop

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    The Airborne Imaging Spectrometer (AIS) Data Analysis Workshop was held at the Jet Propulsion Laboratory on April 8 to 10, 1985. It was attended by 92 people who heard reports on 30 investigations currently under way using AIS data that have been collected over the past two years. Written summaries of 27 of the presentations are in these Proceedings. Many of the results presented at the Workshop are preliminary because most investigators have been working with this fundamentally new type of data for only a relatively short time. Nevertheless, several conclusions can be drawn from the Workshop presentations concerning the value of imaging spectrometry to Earth remote sensing. First, work with AIS has shown that direct identification of minerals through high spectral resolution imaging is a reality for a wide range of materials and geological settings. Second, there are strong indications that high spectral resolution remote sensing will enhance the ability to map vegetation species. There are also good indications that imaging spectrometry will be useful for biochemical studies of vegetation. Finally, there are a number of new data analysis techniques under development which should lead to more efficient and complete information extraction from imaging spectrometer data. The results of the Workshop indicate that as experience is gained with this new class of data, and as new analysis methodologies are developed and applied, the value of imaging spectrometry should increase

    City-regionalism as a politics of collective provision : regional transport infrastructure in Denver, USA

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    The rise of the city-region concept has focused attention on the nature of territorial politics underpinning city-regionalism. This paper investigates the relationship between territorial politics, city-regionalism and the collective provision of mass transport infrastructure in the USA. It deploys a case study of the Denver region, examining the state and governance structures driving forward FasTracks, a long-term project to expand the Denver Regional Transportation District’s light and commuter rail system. FasTracks represents a programme to retrofit the Denver city-region for integrated mass transit but its funding has fostered tensions around new regionalist governance arrangements. The paper uses the findings of the case study to reflect upon the balance of bottom–up versus top–down geopolitical forces shaping the landscape of city-regionalism in the USA. It emphasises the variety of ways in which struggles around infrastructure provision shape the emergence of new city-regionalist structures inside the competition state

    Ten year change in forest succession and composition measured by remote sensing

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    Vegetation dynamics and changes in ecological patterns were measured by remote sensing over a 10 year period (1973 to 1983) for 148,406 landscape elements, covering more than 500 sq km in a protected forested wilderness. Quantitative measurements were made possible by methods to detect ecologically meaningful landscape units; these allowed measurement of ecological transition frequencies and calculation of expected recurrence times. Measured ecological transition frequencies reveal boreal forest wilderness as spatially heterogeneous and highly dynamic, with one-sixth of the area in clearings and early successional stages, consistent with recent postulates about the spatial and temporal patterns of natural ecosystems. Differences between managed forest areas and a protected wilderness allow assessment of different management regimes

    Superconductors with Magnetic Impurities: Instantons and Sub-gap States

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    When subject to a weak magnetic impurity potential, the order parameter and quasi-particle energy gap of a bulk singlet superconductor are suppressed. According to the conventional mean-field theory of Abrikosov and Gor'kov, the integrity of the energy gap is maintained up to a critical concentration of magnetic impurities. In this paper, a field theoretic approach is developed to critically analyze the validity of the mean field theory. Using the supersymmetry technique we find a spatially homogeneous saddle-point that reproduces the Abrikosov-Gor'kov theory, and identify instanton contributions to the density of states that render the quasi-particle energy gap soft at any non-zero magnetic impurity concentration. The sub-gap states are associated with supersymmetry broken field configurations of the action. An analysis of fluctuations around these configurations shows how the underlying supersymmetry of the action is restored by zero modes. An estimate of the density of states is given for all dimensionalities. To illustrate the universality of the present scheme we apply the same method to study `gap fluctuations' in a normal quantum dot coupled to a superconducting terminal. Using the same instanton approach, we recover the universal result recently proposed by Vavilov et al. Finally, we emphasize the universality of the present scheme for the description of gap fluctuations in d-dimensional superconducting/normal structures.Comment: 18 pages, 9 eps figure

    Solidifying system of democracy in the Central and Eastern European new EU members

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    The paper examines the requirements of an effective and legitimized democratic political system in the process of transition. The analysis and the conclusions are based on the Hungarian experience, which can carefully be applied to all Central and Eastern European (CEE) countries. Special focus is given to the relationship of legal certainty and the efficiency of the democratic system, to the tension between legalism and managerialism and to the characteristics of civil society organizations. In the conclusion special features of the transitional countries are pointed out
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