1,549 research outputs found

    Design Methodology and Performance Evaluation of New Generation Sounding Rockets

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    Sounding rockets are currently deployed for the purpose of providing experimental data of the upper atmosphere, as well as for microgravity experiments. This work provides a methodology in order to design, model, and evaluate the performance of new sounding rockets. A general configuration composed of a rocket with four canards and four tail wings is sized and optimized, assuming different payload masses and microgravity durations. The aerodynamic forces are modeled with high fidelity using the interpolation of available data. Three different guidance algorithms are used for the trajectory integration: constant attitude, near radial, and sun-pointing. The sun-pointing guidance is used to obtain the best microgravity performance while maintaining a specified attitude with respect to the sun, allowing for experiments which are temperature sensitive. Near radial guidance has instead the main purpose of reaching high altitudes, thus maximizing the microgravity duration. The results prove that the methodology at hand is straightforward to implement and capable of providing satisfactory performance in term of microgravity duration

    "Insurance industry: challenges on IFRS17 development and implementation"

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    This thesis comes from the consultancy world and a practical problem-solving business case.The aim reflects the will of analyzing the main challenges the imminent financial report standard, the IFRS 17, will lead to the insurance industry. In the first section, it will be defined the general meaning of the argument, then it will be deeply analyzed how the consulting firm in which I have been working with, developed the project for a well-known Italian insurance company. The final part wanted to find a link between the project and the studied academic literature review

    From Frazier to Dale Cooper: The \u27Behavioral Engineering\u27 of Human Learning

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    Among the varied contributions made by B.F. Skinner in a long and distinguished career is the renascence of interest among educators in self-instructional devices issuing from the application of the principles of Skinnerian operant conditioning to human learning situations. Professor Skinner received the A.B. from Hamilton in 1926, the M.A. in 1930, and the Ph.D. in 1931 from Harvard. Between 1936 and 1945, he served as a member of the University of Minnesota faculty, becoming chairman of the department of psychology at Indiana University in 1945 and professor of psychology at Harvard in 1948. His principal books include The Behavior of Organisms (1938), which reported the initial experiments on conditioning the behavior of rats utilizing the famed Skinner Box; Walden Two (1948), a blueprint in fictional form of a culture designed according to the methodology of behavioral engineering; Science and Human Behavior (1953), a text in general psychology; Verbal Behavior (1957), a massive analysis of literary and verbal responses; Schedules of Reinforcement with C. B. Ferster (1957); Cumulative Record (1959), a collection of papers, many of which focus directly upon the development of instructional instruments and the programming of educational materials; and The Analysis of Behavior with J.G. Holland (1961), a programmed textbook both focusing on and illustrating the principles of operant conditioning. The author of this papre, Nathaniel J. Pallone, currently is on the faculty of New York University and is editor of the Journal of the National Catholic Guidance Conference. He is the author of many articles and books

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    Interleukin-23 and Th17 Cells in the Control of Gut Inflammation

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    Crohn's Disease and Ulcerative Colitis, the major forms of inflammatory bowel diseases (IBDs) in humans, have been traditionally associated with exaggerated and poorly controlled T helper (Th) type 1 or Th2 cell response, respectively. More recent studies have, however, shown that IBDs are also characterized by a sustained production of cytokines made by a distinct lineage of Th cells, termed Th17 cells. The demonstration that Th17-related cytokines cause pathology in many organs, including the gut, and that expansion and maintenance of Th17 cell responses require the activity of IL-23, a cytokine made in excess in the gut of IBD patients has contributed to elucidate new pathways of intestinal tissue damage as well as to design new therapeutic strategies. In this review, we discuss the available data supporting the role of the IL-23/Th17 axis in the modulation of intestinal tissue inflammation

    Colorectal Cancer Chemoprevention by Mesalazine and Its Derivatives

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    Patients with inflammatory bowel disease (IBD) face an increased lifetime risk of developing colorectal cancer (CRC). Independent factors associated with increased risk include long disease duration, extensive colonic involvement, young age at onset of IBD, severity of inflammation, primary sclerosing cholangitis, backwash ileitis, and a family history of CRC, thus emphasising the role of intestinal inflammation as an underlying mechanism. This notion is also supported by the demonstration that the use of certain drugs used to attenuate the ongoing mucosal inflammation, such as mesalazine, seems to associate with a reduced incidence of colitis-associated CRC. In the last decade, work from many laboratories has contributed to delineate the mechanisms by which mesalazine alters CRC cell behaviour. In this paper, we review the available experimental data supporting the ability of mesalazine and its derivatives to interfere with intracellular signals involved in CRC cell growth

    Ultrasound of the Small Bowel in Crohn's Disease

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    Several radiological and endoscopic techniques are now available for the study of inflammatory bowel diseases. In everyday practice, the choice of the technique to be used depends upon its availability and a careful evaluation of diagnostic accuracy, clinical usefulness, safety, and cost. The recent development of innovative and noninvasive imaging techniques has led to a new and exciting area in the exploration of the gastrointestinal tract, especially in Crohn's disease patients by using ultrasound with oral or intravenous contrast
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