14 research outputs found
An algorithm for chlorophyll using first difference transformations of AVIRIS reflectance spectra
Experimental results have shown the existence of a strong relationship between chlorophyll alpha concentration and remote sensing reflectance measured at lake level with a high resolution spectroradiometer. The objective of our study was to investigate the relationship between surface chlorophyll alpha concentration at Mono Lake and water reflectance retrieved from Airborne Visible - Infrared Imaging Spectrometer (AVIRIS) data obtained in october 7, 1992. AVIRIS data were atmospherically corrected as described by Green et al. A description of the lake-level sampling is found in Melack and Gastil. The relationship between chlorophyll concentration and both the single band reflectance and the first difference transformation of the reflectance spectra for the first 40 AVIRIS spectral bands (400 nm to 740 nm) was examined. The relationship was then used to produce a map of the surface chlorophyll distribution
Higher Education Exchange: 2007
This annual publication serves as a forum for new ideas and dialogue between scholars and the larger public. Essays explore ways that students, administrators, and faculty can initiate and sustain an ongoing conversation about the public life they share.The Higher Education Exchange is founded on a thought articulated by Thomas Jefferson in 1820: "I know no safe depository of the ultimate powers of the society but the people themselves; and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."In the tradition of Jefferson, the Higher Education Exchange agrees that a central goal of higher education is to help make democracy possible by preparing citizens for public life. The Higher Education Exchange is part of a movement to strengthen higher education's democratic mission and foster a more democratic culture throughout American society.Working in this tradition, the Higher Education Exchange publishes interviews, case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies
Assessing Group-Level Constructs Under Missing Data Conditions: A Monte Carlo Simulation
Regionalization of methane emissions in the Amazon Basin with microwave remote sensing
Wetlands of the Amazon River basin are globally significant sources of atmospheric methane. Satellite remote sensing (passive and active microwave) of the temporally varying extent of inundation and vegetation was combined with field measurements to calculate regional rates of methane emission for Amazonian wetlands. Monthly inundation areas for the fringing floodplains of the mainstem Solimões/Amazon River were derived from analysis of the 37 GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer from 1979 to 1987. L-band synthetic aperture radar data (Japanese Earth Resources Satellite-1) were used to determine inundation and wetland vegetation for the Amazon basin (<500 m elevation) at high (May-June 1996) and low water (October 1995). An extensive set of measurements of methane emission is available from the literature for the fringing floodplains of the central Amazon, segregated into open water, flooded forest and floating macrophyte habitats. Uncertainties in the regional emission rates were determined by Monte Carlo error analyses that combined error estimates for the measurements of emission and for calculations of inundation and habitat areas. The mainstem Solimões/Amazon floodplain (54-70°W) emitted methane at a mean annual rate of 1.3 Tg C yr-1, with a standard deviation (SD) of the mean of 0.3 Tg C yr-1; 67% of this range in uncertainty is owed to the range in rates of methane emission and 33% is owed to uncertainty in the areal estimates of inundation and vegetative cover. Methane emission from a 1.77 million square kilometers area in the central basin had a mean of 6.8 Tg C yr-1 with a SD of 1.3 Tg C yr-1. If extrapolated to the whole basin below the 500 m contour, approximately 22 Tg C yr-1 is emitted; this mean flux has a greenhouse warming potential of about 0.5 Pg C as CO2. Improvement of these regional estimates will require many more field measurements of methane emission, further examination of remotely sensed data for types of wetlands not represented in the central basin, and process-based models of methane production and emission. © 2004 Blackwell Publishing Ltd
Assessing the Validity of Different Approaches to Operationalizing Cultural Theory in Survey Research
Gender and Public Talk
This article develops a theory of the gendered character of public talk as a way to account for women's variable participation in the settings that make up the public sphere. Public settings for citizen talk such as radio call-in shows, social networking sites, letters to the editor, and town hall meetings are culturally coded female or male. In feminized settings, where the people who organize public talk are from feminized professions and where the favored modes of talk and action emphasize stereotypically feminine values, women are likely to be as active and influential participants as men. We test this proposition by way of an examination of the organized public deliberative forums in which many Americans today discuss policy issues. We show that women truly are equal participants in these forums. We account for this surprising development by demonstrating the female gendered character of the contemporary field of organized public deliberation. © American Sociological Association 2013