Monitoring water quality from LANDSAT

Water quality monitoring possibilities from LANDSAT were demonstrated both for direct readings of reflectances from the water and indirect monitoring of changes in use of land surrounding Swift Creek Reservoir in a joint project with the Virginia State Water Control Board and NASA. Film products were shown to have insufficient resolution and all work was done by digitally processing computer compatible tapes. Land cover maps of the 18,000 hectare Swift Creek Reservoir watershed, prepared for two dates in 1974, are shown. A significant decrease in the pine cover was observed in a 740 hectare construction site within the watershed. A measure of the accuracy of classification was obtained by comparing the LANDSAT results with visual classification at five sites on a U-2 photograph. Such changes in land cover can alert personnel to watch for potential changes in water quality

Relative radiometric calibration of LANDSAT TM reflective bands

Raw thematic mapper (TM) calibration data from pre-launch tests and in-orbit acquisitions from LANDSAT 4 and 5 satellites are analyzed to assess the radiometric characteristics of the TM sensor. A software program called TM radiometric and algorithmic performance program (TRAPP) was used for the majority of analyses. Radiometric uncertainty in the final TM image originates from: (1) scene variability (solar irradiance and atmospheric scattering); (2) optical and electrical variability of the sensor; and (3) variability introduced during image processing

Spectral characterization of the LANDSAT Thematic Mapper sensors

The spectral coverage characteristics of the two thematic mapper instruments were determined by analyses of spectral measurements of the optics, filters, and detectors. The following results are presented: (1) band 2 and 3 flatness was slightly below specification, and band 7 flatness was below specification; (2) band 5 upper-band edge was higher than specifications; (3) band 2 band edges were shifted upward about 9 nm relative to nominal; and (4) band 4, 5, and 7 lower band edges were 16 to 18 nm higher then nominal

Introduction to Thematic Mapper investigations. Section 1: Radiometry. Section 2: Geometry

An overview of papers which deal with radiometric characterization of the TM sensor is presented. Spectral characteristics are summarized. The geometric accuracy of TM are also examined. Aspects of prelaunch and post launch sensor performance, ground processing techniques, and error correction are also investigated

Spectral characterization of the LANDSAT-D multispectral scanner subsystems

Relative spectral response data for the multispectral scanner subsystems (MSS) to be flown on LANDSAT-D and LANDSAT-D backup, the protoflight and flight models, respectively, are presented and compared to similar data for the Landsat 1,2, and 3 subsystems. Channel-bychannel (six channels per band) outputs for soil and soybean targets were simulated and compared within each band and between scanners. The two LANDSAT-D scanners proved to be nearly identical in mean spectral response, but they exhibited some differences from the previous MSS's. Principal differences between the spectral responses of the D-scanners and previous scanners were: (1) a mean upper-band edge in the green band of 606 nm compared to previous means of 593 to 598 nm; (2) an average upper-band edge of 697 nm in the red band compared to previous averages of 701 to 710 nm; and (3) an average bandpass for the first near-IR band of 702-814 nm compared to a range of 693-793 to 697-802 nm for previous scanners. These differences caused the simulated D-scanner outputs to be 3 to 10 percent lower in the red band and 3 to 11 percent higher in the first near-IR band than previous scanners for the soybeans target. Otherwise, outputs from soil and soybean targets were only slightly affected. The D-scanners were generally more uniform from channel to channel within bands than previous scanners

Analytical method for determining the stability of linear retarded systems with two delays

The stability is considered of the solution differential-difference equations of the retarded type with constant coefficients and two constant time delays. A method that makes use of analytical expressions to determine stability boundaries, and the stability of the system, is derived. The method was applied to a system represented by a second-order differential equation with constant coefficients and time delays in the velocity and displacement terms. The results obtained is in agreement with those obtained by other investigators

Stability of neutral equations with constant time delays

A method was developed for determining the stability of a scalar neutral equation with constant coefficients and constant time delays. A neutral equation is basically a differential equation in which the highest derivative appears both with and without a time delay. Time delays may appear also in the lower derivatives or the independent variable itself. The method is easily implemented, and an illustrative example is presented

LANDSAT-4 sensor performance

Preflight and in-orbit sensor and data measurements indicate that TM meets or exceeds most specifications. Measured spectral band edges meet instrument specifications in 12 out of 14 cases; there is ample dynamic range. The signal-to-noise ratio exceeds specifications, except for band 3, channel 4; and band 7 channel 7 is very noisy but still meets specifications. The modulation transfer function of channel 4, band 2, is smaller than specified. Registration errors between the primary focal plane (PFP) and the cold focal plane (CFP) are about 0.75 pixels along-scan and 0.2 pixels across scan. Forward and reverse scan discontinuities, are well within ground-processing capabilities to rectify. Instrument gain variability, up to 7% for band 5, requires use of the internal calibration (IC) system to assure radiometric accuracy. Preliminary applications evaluation of image contents indicates that TM provides much better definition of edges than MSS

Mediated intimacy: Sex advice in media culture

The bold argument of Mediated Intimacy (Barker et al., 2018)1 is that media of various kinds play an increasingly important role in shaping people’s knowledge, desires, practices and expectations about intimate relationships. While arguments rage about the nature and content of sex and relationship education in schools, it is becoming clear that more and more of us – young and old – look not to formal education, or even to our friends, for information about sex, but to the media (Albury, 2016; Attwood et al., 2015). This is not simply a matter of media ‘advice’ in the form of self-help books, magazine problem pages, or online ‘agony’ columns – though these are all proliferating and are discussed at length in the book. It is also about the wider cultural habitat of images, ideas and discourses about intimacy that circulate through and across media: the ‘happy endings’ of romantic comedies; the ‘money shots’ of pornography; the celebrity gossip about who is seeing whom, who is ‘cheating’, and who is looking ‘hot’; the lifestyle TV about ‘embarrassing bodies’ or being ‘undateable’; the newspaper features on how to have a ‘good’ divorce or ‘ten things never to say on a first date’; the new apps that incite us to quantify and rate our sex lives, and so forth. These constitute the ‘taken for granted’ of everyday understandings of intimacy, and they are at the heart of Mediated Intimacy

A square-well model for the structural and thermodynamic properties of simple colloidal systems

A model for the radial distribution function $g(r)$ of a square-well fluid of variable width previously proposed [S. B. Yuste and A. Santos, J. Chem. Phys. {\bf 101}, 2355 (1994)] is revisited and simplified. The model provides an explicit expression for the Laplace transform of $rg(r)$, the coefficients being given as explicit functions of the density, the temperature, and the interaction range. In the limits corresponding to hard spheres and sticky hard spheres the model reduces to the analytical solutions of the Percus-Yevick equation for those potentials. The results can be useful to describe in a fully analytical way the structural and thermodynamic behavior of colloidal suspensions modeled as hard-core particles with a short-range attraction. Comparison with computer simulation data shows a general good agreement, even for relatively wide wells.Comment: 23 pages, 10 figures; Figs. 4 and 5 changed, Fig. 6 new; to be published in J. Chem. Phy