Distinguishable Density Levels in Image Recording of Earth Resources Satellite Data

The Earth Resources Technology Satellite (ERTS) system produces a large volume of images of the Earth, with exposed film as the final output. These Images are presented to the user in pictorial form for interpretation and analysis. Specifications for this output film include MTF requirements, development method requirements, geometric tolerance and the number of DDL\u27s (distinguishable density levels). Given the specification of 64 levels of gray, with a minimum density range of 2.0, the following investigation is warranted. Using theoretical calculations, granularity will be determined at different density levels. Assuming that Selwyn\u27s Law is valid for the range of apertures and films in this specific investigation, granularity as a function of density will be calculated. Further, assuming these calculations are valid, a procedure will be established by which films can be selected for the ERTS project, solely on the basis of these calculations. Several experiments were performed to evaluate the merit of the theoretical calculations. The results were similar, however inconclusive. A series of experiments were performed in attempt to establish a new measure by which the films could be judged. The sum of the variations caused by granularity, area to area variation and pixel to pixel interaction were generated with this new technique

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http://deepblue.lib.umich.edu/bitstream/2027.42/111657/1/tbeiser_1429755468.pd

A Survey of Larval Caddisflies (Insecta: Trichoptera) from Riffles of Three Streams of the Drake\u27s Creek Drainage, Kentucky, with a Preliminary Investigation of the Adult Trichoptera of the Region

A total of 1665 larval caddisflies, representing four families and eight genera, was collected from seven stations in the Drake\u27s Creek drainage from 1 November, 1982 through 15 October, 1983. The pattern of longitudinal distribution of the larvae, based on feeding relationships, in the West and Middle Forks of the system was consistent with studies by Wiggins and Mackay (1978), Andrews and Minshall (1979), and Ross and Wallace (1982) and the River Continuum Concept (Vannote et al. 1980). The Trammel Fork, a spring fed stream, showed a pattern of distribution contrary to the predictions of the Concept, suggesting that the continuous gradient of physical conditions upon which the Concept was based may not be present in streams where hypogean inflows constitute a major part of the water volume. One larva collected represented a new species record for Kentucky. Light trap collections of adult caddisflies yielded 28 species representing eight families and 15 genera, suggesting an extremely diverse trichopteran fauna in the Drake\u27s Creek drainage. In addition, the first reported species records for Trichoptera in Allen and Simpson Counties as well as 21 additional records for Warren County were established. Three of the species of adult Trichoptera reported represented new species records for Kentucky

A Capability Approach to Examining the Effects of Actual and Anticipated Fear of Crime: Experiences and Perceptions of Black Female Youth in the Cape Flats

The purpose of this study was to examine how the fear of crime affects the capabilities, perceptions and experiences of black female youth, living in the Cape Flats, Cape Town. Qualitative semi structured interviews were conducted with 18 black female participants between the ages of 18 to 30. This study used Garofalo's model of fear of crime and Amartya Sen's capability approach as theoretical frameworks. With the help of these two frameworks, the researcher sought to gauge what influence the fear of crime can have on people's lives and how crime affects young black females living in communities with high crime rates. It also showed how their life choices and opportunities are influenced by living in unsafe communities. The major challenges and problems highlighted by the participants include: Constant trauma of their daily life (leaving their houses, random shootings, unsafe public transport), mental health issues (losing friends and relatives), lack of proper police service (lack of police presence, incompetence of police, corruption), fear for family or friends, lack of trust and support systems (broken families, loss of trust, no role models, lack of social capital), lack of infrastructure (such as safe hospitals or educational challenges), the effects of gangsterism (gangs and drug wars, effects of drugs, families' or friend's involvement in gangsterism) and the lack of opportunities such as unemployment. This study showed how the peoples' capabilities have been affected by the above-mentioned issues and how the fear of crime affected their daily lives. This study also made recommendations for policy makers and social institutions on what can be done to reduce crime rates and make communities with high crime rates safe

Separation and Rare Events

When separation is a problem in binary dependent variable models, many researchers use Firth's penalized maximum likelihood in order to obtain finite estimates (Firth, 1993; Zorn, 2005; Rainey, 2016). In this paper, I show that this approach can lead to inferences in the opposite direction of the separation when the number of observations are sufficiently large and both the dependent and independent variables are rare events. As large datasets with rare events are frequently used in political science, such as dyadic data measuring interstate relations, a lack of awareness of this problem may lead to inferential issues. Simulations and an empirical illustration show that the use of independent weakly-informative prior distributions centered at zero, for example, the Cauchy prior suggested by Gelman et al. (2008), can avoid this issue. More generally, the results caution researchers to be aware of how the choice of prior interacts with the structure of their data, when estimating models in the presence of separation