Valuing Natural Space and Landscape Fragmentation in Richmond, VA

Hedonic pricing methods and GIS (Geographic Information Systems) were used to evaluate relationships between sale price of single family homes and landscape fragmentation and natural land cover. Spatial regression analyses found that sale prices increase as landscapes become less fragmented and the amount of natural land cover around a home increases. The projected growth in population and employment in the Richmond, Virginia region and subsequent increases in land development and landscape fragmentation presents a challenge to sustaining intact healthy ecosystems in the Richmond region. Spatial regression analyses helped illuminate how land cover patterns influence sale prices and landscape patterns that are economically and ecologically advantageous

Thrust vectoring for lateral-directional stability

The advantages and disadvantages of using thrust vectoring for lateral-directional control and the effects of reducing the tail size of a single-engine aircraft were investigated. The aerodynamic characteristics of the F-16 aircraft were generated by using the Aerodynamic Preliminary Analysis System II panel code. The resulting lateral-directional linear perturbation analysis of a modified F-16 aircraft with various tail sizes and yaw vectoring was performed at several speeds and altitudes to determine the stability and control trends for the aircraft compared to these trends for a baseline aircraft. A study of the paddle-type turning vane thrust vectoring control system as used on the National Aeronautics and Space Administration F/A-18 High Alpha Research Vehicle is also presented

Walkability Assessment to Reduce Childhood Obesity in Wilson County Kansas

Promoting physical exercise is necessary to combat childhood obesity. Walking to school is an encouraged physical activity, but the feasibility of walking to school depends on the walkability of the environment. During the last 40 years, the number of U.S. schoolchildren who walk to school has declined. The purpose of this evidence-based practice project was to perform a walkability assessment of the 2 largest communities in Wilson County Kansas to identify and address walkability issues. Frameworks for this practice initiative were social cognitive theory and the Health Promotion model. Questions for the project addressed whether sidewalks along the main pedestrian routes leading to the schools were in good enough condition to allow children to walk safely to and from school. Using an adapted tool from the Pedestrian Safety and Mobility Audit Guide, assessment of the condition of the sidewalks was completed using the key characteristics of the sidewalks such as width, evenness, surface, and condition in the 2 major school routes. Results indicated no safe walk route in Fredonia. In Neodesha, only the sidewalks on the west side of 8th Street were in excellent condition. Safety issues identified during the assessment led to recommendation of safe pedestrian travel on only one route to school. Findings may be used to promote daily physical exercise for children, which may reduce the risk for obesity and promote social change for the community

A Stable Clock Error Model Using Coupled First and Second Order Gauss-Markov Processes

Long data outages may occur in applications of global navigation satellite system technology to orbit determination for missions that spend significant fractions of their orbits above the navigation satellite constellation(s). Current clock error models based on the random walk idealization may not be suitable in these circumstances, since the covariance of the clock errors may become large enough to overflow flight computer arithmetic. A model that is stable, but which approximates the existing models over short time horizons is desirable. A coupled first- and second-order Gauss-Markov process is such a model

Implantable Microenvironments to Capture Stable-to- Aggressive Tumor Transition

Clinical stability occurs when cancers reach a state where the disease neither advances nor regresses. Tumors can remain in this state for multiple years before progressing to more aggressive phenotypes. The mechanisms for maintaining a stable state and the factors that contribute to tumor activation are poorly understood. We hypothesized that an implantable biomaterial scaffold would be able to isolate a population of stable tumor cells that could then be used to study the transition to an aggressive phenotype. In this work we developed a tunable and highly controlled, porous acrylamide scaffold and subcutaneously implanted them in immunodeficient (NSG) mice. Prior to implantation scaffolds were seeded with a variety of different cell types. Specifically, human bone marrow stromal cells were supplemented with mouse stromal cells genetically engineered to express human cytokines to promote the generation of different tissue microenvironments in the scaffolds. After implantation the mice received an orthotopic injection of either human breast or prostate cancer cells. The tumors were allowed to generate metastases to the scaffolds and other tissues. Scaffolds were transplanted to non-tumor bearing mice once the tumor burden became exhaustive to the host to allow for further study of the microenvironment. The role of immune cells on the tumor microenvironment was also explored. Human peripheral blood mononuclear cells were isolated from donors and injected intravenously prior to transplantation. Bioluminescent imaging was used to capture tumor growth in vivo over a ten week period. The scaffolds were analyzed via immunohistochemical staining on thinly sectioned tissue and intact tissue cleared samples to characterize the tissue microenvironment and its effect on tumor progression. Our work has demonstrated the application of implantable tissue engineered microenvironments to study the phenomena of tumor stability in vivo and has uncovered some potentially important factors that drive the transition from stable to aggressive tumors

The architecture of a video image processor for the space station

The architecture of a video image processor for space station applications is described. The architecture was derived from a study of the requirements of algorithms that are necessary to produce the desired functionality of many of these applications. Architectural options were selected based on a simulation of the execution of these algorithms on various architectural organizations. A great deal of emphasis was placed on the ability of the system to evolve and grow over the lifetime of the space station. The result is a hierarchical parallel architecture that is characterized by high level language programmability, modularity, extensibility and can meet the required performance goals