Spatial and spectral resolution necessary for remotely sensed vegetation studies

An outline is presented of the required spatial and spectral resolution needed for accurate vegetation discrimination and mapping studies as well as for determination of state of health (i.e., detection of stress symptoms) of actively growing vegetation. Good success was achieved in vegetation discrimination and mapping of a heterogeneous forest cover in the ridge and valley portion of the Appalachians using multispectral data acquired with a spatial resolution of 15 m (IFOV). A sensor system delivering 10 to 15 m spatial resolution is needed for both vegetation mapping and detection of stress symptoms. Based on the vegetation discrimination and mapping exercises conducted at the Lost River site, accurate products (vegetation maps) are produced using broad-band spectral data ranging from the .500 to 2.500 micron portion of the spectrum. In order of decreasing utility for vegetation discrimination, the four most valuable TM simulator VNIR bands are: 6 (1.55 to 1.75 microns), 3 (0.63 to 0.69 microns), 5 (1.00 to 1.30 microns) and 4 (0.76 to 0.90 microns)

Preliminary Analysis of AIS Spectral Data Acquired from Semi-arid Shrub Communities in the Owens Valley, California

Spectral characteristics of semic-arid plant communities using 128 channel airborne imaging spectrometer (AIS) data acquired on October 30, 1984. Both field and AIS spectra of vegetation were relatively featureless and differed from substrate spectra primarily in albedo. Unvegetated sand dunes were examined to assess spectral variation resulting from topographic irregularity. Although shrub cover as low as 10% could be detected on relatively flat surfaces, such differences were obscured in more heterogeneous terrain. Sagebrush-covered fans which had been scarred by fire were studied to determine the effect of changes in plant density on reflectance. Despite noise in the atmospherically corrected spectra, these provide better resolution of differences in plant density than spectra which are solar-corrected only. A high negative correlation was found between reflectance and plant cover in areas which had uniform substrates and vegetation types. A lower correlation was found where vegetation and substrates were more diverse

Spectral Characterization of Suspected Acid Deposition Damage in Red Spruce (picea Rubens) Stands from Vermont

In an attempt to demonstrate the utility of remote sensing systems to monitor sites of suspected acid rain deposition damage, intensive field activities, coupled with aircraft overflights, were centered on red spruce stands in Vermont during August and September of 1984. Remote sensing data were acquired using the Airborne Imaging Spectrometer, Thematic Mapper Simulator, Barnes Model 12 to 1000 Modular Multiband Radiometer and Spectron Engineering Spectrometer (the former two flown on the NASA C-130; the latter two on A Bell UH-1B Iroquois Helicopter). Field spectral data were acquired during the week of the August overflights using a high spectral resolution spectrometer and two broad-band radiometers. Preliminary analyses of these data indicate a number of spectral differences in vegetation between high and low damage sites. Some of these differences are subtle, and are observable only with high spectral resolution sensors; others are less subtle and are observable using broad-band sensors

Elastic suspension of a wind tunnel test section

Experimental verification of the theory describing arbitrary motions of an airfoil is reported. The experimental apparatus is described. A mechanism was designed to provide two separate degrees of freedom without friction or backlash to mask the small but important aerodynamic effects of interest

Noncooperative Household Consumption with Caring

We present a household consumption model that accounts for caring house- hold members, while allowing for noncooperative behavior in decisions on pub- lic goods. The intrahousehold consumption outcome critically depends on the degree of caring between the household members. By varying the degree of in- trahousehold caring, the model encompasses a whole continuum of household consumption models that are situated between the fully cooperative model and the noncooperative model without caring. This feature is used to define a measure for the degree of cooperation within the household. We also establish a dual characterization of our noncooperative model with caring preferences: we show that the model is dually equivalent to a noncooperative model with non-caring preferences that is characterized by intrahousehold transfers. Fi- nally, following a revealed preference approach, we derive testable implications of the model for empirical data. We demonstrate the practical usefulness of the model through an illustrative application.household consumption;caring preferences;intrahousehold coop- eration;Nash equilibrium;revealed preferences

Antigen presentation by hapten-specific B lymphocytes. I. Role of surface immunoglobulin receptors.

The present study examines the ability of hapten-specific murine splenic B lymphocytes to present hapten-proteins to carrier-specific T cell hybridomas. BALB/cB cells specific for 2,4,6-trinitrophenyl (TNP) were isolated from spleens of immune mice by elution from TNP-gelatin-coated dishes. Such cells presented the TNP-modified terpolymer, GL phi, at concentrations as low as 0.1 microgram/ml, to a GL phi-specific, I-Ed-restricted, interleukin 2-producing T cell hybridoma. In contrast, the same B lymphocytes required 1,000-fold higher concentrations of unmodified GL phi to stimulate the same T cell hybridoma. The presentation of low concentrations of TNP-GL phi by TNP-specific B lymphocytes was significantly or completely blocked by anti-Ig antibody or TNP-proteins, indicating that surface Ig receptors were critically involved in this phenomenon. Finally, binding of TNP-proteins did not alter the ability of the B cells to present unrelated, unhaptenated proteins or to stimulate alloreactive T cells. These results suggest that surface Ig receptors serve to focus antigens onto specific B lymphocytes and that such cells are highly efficient at presenting linked antigenic determinants to T cells. The implications of these findings for the mechanisms of physiologic, histocompatibility-restricted T-B collaboration are discussed

The Revealed Preference Approach to Collective Consumption Behavior: Nonparametric Testing and Sharing Rule Recovery (Revised version of CentER DP 2007-73)

We present a nonparametric 'revealed preference' methodology for empiri- cally analyzing collective consumption behavior. First, we introduce an integer programming (IP) methodology for testing data consistency with collective con- sumption models that account for publicly as well as privately consumed goods. This IP methodology can include information on 'assignable quantities' for pri- vate goods. Next, we show that the IP methodology allows for recovering the personalized (Lindahl) prices for the public goods and the personalized quan- tities for the private goods. In turn, this implies recovery of the sharing rule (i.e. personalized income share levels). Numerical examples and an empirical application demonstrate the practical usefulness of the methodology.collective model;revealed preferences;data consistency tests;re- covery;integer programming;sharing rule

Opening the Black Box of Intra-Household Decision-Making: Theory and Non-Parametric Empirical Tests of General Collective Consumption Models

We non-parametrically test a general collective consumption model with public consumption and externalities inside the household.We further propose a novel approach to model special cases of the general collective model.These special cases include alternative restrictions on the 'sharing rule' that applies to each household, and which defines the distribution of the household budget over the household members.A limiting case is the unitary model.Our application uses data from the Russia Longitudinal Monitoring Survey (RLMS); the panel structure of this data set allows non-parametric testing of the behavioral models without relying on preference homogeneity assumptions across similar individuals.This application includes test results but also a power analysis for different specifications of the collective consumption model.Our main findings are that the most general collective model, together with a large class of special but still fairly general cases, cannot be rejected by the data, while other restricted versions of the general model, including the unitary alternative, are rejected.Since these tests are entirely non-parametric, this provides strong evidence in favor of models focusing on intra-household decisionmaking.collective household models;intra-household allocation;revealed pref- erences;non-parametric analysis

Married with Children: A Collective Labor Supply Model with Detailed Time Use and Intrahousehold Expenditure Information

We propose a collective labor supply model with household production that generalizes an original model of Blundell, Chiappori and Meghir (2005). In our model, adults' individual preferences do not only depend on own leisure and individual private consumption of market goods. They also depend on the con- sumption of domestic goods, which are produced by combining goods bought at the market with individuals' time. We apply our model to new and unique data on Dutch couples with children. The data contains detailed information about the spouses' time use and the intrahousehold allocation of all expendi- tures. Our application uses a novel estimation strategy that builds upon the familiar two-stage allocation representation of the collective model. We obtain interesting (and plausible) empirical results. Spouses' preferences depend on the consumption of domestically produced goods (including children's welfare). Next, Pareto weights depend on variables like the individual wages and the share in the households nonlabor income. Finally, and perhaps surprisingly, we do not find evidence that mothers care more for their children than fathers.collective model;labor supply;time use;public goods;household production

Is Utility Transferable? A Revealed Preference Analysis

We provide a revealed preference analysis of the transferable utility hypothesis, which is widely used in economic models. First, we establish revealed preference conditions that must be satisfied for observed group behavior to be consistent with Pareto efficiency under transferable utility. Next, we show that these conditions are easily testable by means of integer programming methods. The tests are entirely nonparametric, which makes them robust with respect to specification errors. Finally, we demonstrate the practical usefulness of our conditions by means of an application to Spanish consumption data. To the best of our knowledge, this is the first empirical test of the transferable utility hypothesis.transferable utility hypothesis;generalized quasi-linearity;nonparamet- ric tests;revealed preferences