YF-12 Lockalloy ventral fin program, volume 1

Results are presented of the YF-12 Lockalloy Ventral Fin Program which was carried out by Lockheed Aircraft Corporation - Advanced Development Projects for the joint NASA/USAF YF-12 Project. The primary purpose of the program was to redesign and fabricate the ventral fin of the YF-12 research airplane (to reduce flutter) using Lockalloy, and alloy of beryllium and aluminum, as a major structural material. A secondary purpose, was to make a material characterization study (thermodynamic properties, corrosion; fatigue tests, mechanical properties) of Lockalloy to validate the design of the ventral fin and expand the existing data base on this material. All significant information pertinent to the design and fabrication of the ventral fin is covered. Emphasis throughout is given to Lockalloy fabrication and machining techniques and attendant personnel safety precautions. Costs are also examined. Photographs of tested alloy specimens are shown along with the test equipment used

Association of West Nile virus illness and urban landscapes in Chicago and Detroit

BACKGROUND: West Nile virus infection in humans in urban areas of the Midwestern United States has exhibited strong spatial clustering during epidemic years. We derived urban landscape classes from the physical and socio-economic factors hypothesized to be associated with West Nile Virus (WNV) transmission and compared those to human cases of illness in 2002 in Chicago and Detroit. The objectives were to improve understanding of human exposure to virus-infected mosquitoes in the urban context, and to assess the degree to which environmental factors found to be important in Chicago were also found in Detroit. RESULTS: Five urban classes that partitioned the urban space were developed for each city region. The classes had many similarities in the two settings. In both regions, the WNV case rate was considerably higher in the urban class associated with the Inner Suburbs, where 1940–1960 era housing dominates, vegetation cover is moderate, and population density is moderate. The land cover mapping approach played an important role in the successful and consistent classification of the urban areas. CONCLUSION: The analysis demonstrates how urban form and past land use decisions can influence transmission of a vector-borne virus. In addition, the results are helpful to develop hypotheses regarding urban landscape features and WNV transmission, they provide a structured method to stratify the urban areas to locate representative field study sites specifically for WNV, and this analysis contributes to the question of how the urban environment affects human health

YF-12 Lockalloy ventral fin program, volume 2

For abstract, see N76-23252

Using Technology and Media-Rich Platforms to help teach the Pythagorean Theorem

The history of mathematics is quite extensive, dating back to ancient times and elapsing several centuries. Many great mathematicians, philosophers, scientists, and scholars have contributed to mathematics on the subject we see today. For the purpose of this research project, we have chosen to highlight the great mathematician Pythagoras and his famous Pythagorean Theorem. We investigate the history of the Pythagorean Theorem, relationships among Pythagorean numbers, and unusual proofs of the Theorem. This paper provides a suggestive lesson plan, activity, and presentation for classroom use

Using Number Properties to inspire teaching and learning in the K-12 Classrooms

Where would today’s world be without the number system? Indeed, civilization would not have come to as far as in modern times. In fact, the software this paper is being written on is run by a computer that is embedded in numerical codes and commands– something that would not be possible if it were not for the advancement of technology using the modern number system. In this paper, we study the historical development of the modern-day number system. We investigate the classification of numbers and number properties for mathematical use; including standard functions, rules, and examples. As a culmination of our research, we provide a comprehensive activity for classroom use, accompanied by worksheets and a classroom-ready presentation

Number Pattern

In this manuscript, we study the purpose of number patterns, a brief history of number patterns, and classroom uses for number patterns and magic squares. We investigate and summarize number patterns and magic squares in various charts: 6 x 6, 7 x 7, 13 x 13, 21 x 21, and 37 x 37. The results are established by each number pattern along with narrative conjectures about primes and multiples of six from each pattern. Numerical charting examples are provided as an illustration of the theoretical results

Introduction of Aedes albopictus into a La Crosse virus--enzootic site in Illinois.

In late summer and fall 1997, Aedes albopictus mosquitoes were found in Peoria, Illinois, a long recognized focus of La Crosse virus transmission. Larvae were found in tires and other artificial containers, biting adults were recovered, and eggs were collected in oviposition traps within a 25-ha area. One chipmunk trapped < 0.25 km from the infested area tested positive for neutralizing antibodies against La Crosse virus

Polystyrene nanoplastics disrupt glucose metabolism and cortisol levels with a possible link to behavioural changes in larval zebrafish

Plastic nanoparticles originating from weathering plastic waste are emerging contaminants in aquatic environments, with unknown modes of action in aquatic organisms. Recent studies suggest that internalised nanoplastics may disrupt processes related to energy metabolism. Such disruption can be crucial for organisms during development and may ultimately lead to changes in behaviour. Here, we investigated the link between polystyrene nanoplastic (PSNP)-induced signalling events and behavioural changes. Larval zebrafish exhibited PSNP accumulation in the pancreas, which coincided with a decreased glucose level. By using hyperglycemic and glucocorticoid receptor (Gr) mutant larvae, we demonstrate that the PSNP-induced disruption in glucose homoeostasis coincided with increased cortisol secretion and hyperactivity in challenge phases. Our work sheds new light on a potential mechanism underlying nanoplastics toxicity in fish, suggesting that the adverse effect of PSNPs are at least in part mediated by Gr activation in response to disrupted glucose homeostasis, ultimately leading to aberrant locomotor activity

The Polycomb group protein Ring1b is essential for pectoral fin development

Animal science