4,852 research outputs found
Investigations of simulated aircraft flight through thunderstorm outflows
The effects of wind shear on aircraft flying through thunderstorm gust fronts were investigated. A computer program was developed to solve the two dimensional, nonlinear equations of aircraft motion, including wind shear. The procedure described and documented accounts for spatial and temporal variations of the aircraft within the flow regime. Analysis of flight paths and control inputs necessary to maintain specified trajectories for aircraft having characteristics of DC-8, B-747, augmentor wing STOL, and DHC-6 aircraft was recorded. From the analysis an attempt was made to find criteria for reduction of the hazards associated with landing through thunderstorm gust fronts
Studies in the history of the song school at Durham from the early fifteenth century to the early eighteenth century
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Frequency distributions: from the sun to the earth
The space environment is forever changing on all spatial and temporal scales. Energy releases are observed in numerous dynamic phenomena (e.g. solar flares, coronal mass ejections, solar energetic particle events) where measurements provide signatures of the dynamics. Parameters (e.g. peak count rate, total energy released, etc.) describing these phenomena are found to have frequency size distributions that follow power-law behavior. Natural phenomena on Earth, such as earthquakes and landslides, display similar power-law behavior. This suggests an underlying universality in nature and poses the question of whether the distribution of energy is the same for all these phenomena. Frequency distributions provide constraints for models that aim to simulate the physics and statistics observed in the individual phenomenon. The concept of self-organized criticality (SOC), also known as the "avalanche concept", was introduced by Bak et al. (1987, 1988), to characterize the behavior of dissipative systems that contain a large number of elements interacting over a short range. The systems evolve to a critical state in which a minor event starts a chain reaction that can affect any number of elements in the system. It is found that frequency distributions of the output parameters from the chain reaction taken over a period of time can be represented by power-laws. During the last decades SOC has been debated from all angles. New SOC models, as well as non-SOC models have been proposed to explain the power-law behavior that is observed. Furthermore, since Bak's pioneering work in 1987, people have searched for signatures of SOC everywhere. This paper will review how SOC behavior has become one way of interpreting the power-law behavior observed in natural occurring phenomenon in the Sun down to the Earth
Obesity Prevalence and Dietary Intake of Antioxidants in Native American Adolescents
Antioxidants are well known for possessing anti-inflammatory properties, which can reduce the risk of chronic disease and obesity. However, very little research has been done to examine antioxidant intake among adolescent minority populations such as Native American adolescents. Our study examined the significance of antioxidant intake among Native American adolescents at an urban residential high school in Southern California. Our study population consisted of 183 male and female Native American adolescents, 14-18 years of age, representing 43 tribes from across the United States. Students' primary source of meals was provided by the school food service. Based on the BMI calculations, the rate of obesity within our population was 38% for males and 40% for females, more than two-fold the national rate indicated by NHANESIII data. We used the Harvard School of Public Health Youth/Adolescent Questionnaire (HSPH YAQ), a semi-quantitative food frequency questionnaire, to examine antioxidant nutrient intake and evaluate the differences in the intake between normal and obese weight students. Statistical analysis of the results showed that intakes of vitamins C, E, and lycopene were the antioxidant nutrients found to be significantly different between normal and obese weight students and intakes of these nutrients were found to be higher among normal weight students (p-values = 0.02451, 0.00847, and 0.04928, respectively). These results suggest that dietary intake of antioxidants could be increased among Native American adolescents. Further research is needed to confirm our findings and identify effective ways for school food service to incorporate antioxidant rich foods into school menus
C2O and Frontyard: hacking the archives to design community spaces in Surabaya and Sydney
© 2019, Luke Bacon, Kathleen Azali, Alexandra Lara Crosby and Benjamin Forster. Purpose: The purpose of this study is to identify shared themes and concerns of two local and critical archives by comparing their design and day-to-day practice. Design/methodology/approach: The action research has drawn on the experience of collaboration between a Sydney-based community space (Frontyard) and the Surabaya-based co-working community (C2O) over one year. Each space houses a small physical library of books, which is the focus of this analysis. Findings: Hacking has emerged as a key value of both archives. A hacking approach has shaped the design of each space and the organisation each archive. Hacking frames the analysis of each collection in this study. Practical implications: Pragmatic and political understanding of such archives have implications for better quality and more authentic exchange between the communities that make use of these libraries in Indonesia and Australia. Originality/value: While some work on local critical archives has been done in Indonesia and Australia, no research to date has made specific comparisons with the aim of sharing knowledge. Because these archives are often temporary and ephemeral, documenting the work that goes into them, and their practitioners’ perspectives, is urgent, making possible shared knowledge that can inform the ways communities make decisions about their own heritage
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