Search results for: R. Westcott

Authors: Lauren Zammerilla Westcott, Ronald C. Jones, James W. Fleshman

Abstract:

The surgical treatment of breast cancer has rapidly evolved over the past 50 years, progressing from Halsted’s radical mastectomy to a public campaign of surgical options, aesthetic reconstruction, and patient empowerment. This article examines the happenings that led to the transition of breast surgery as a subset of general surgery to its own specialized field. Sparked by the research of Dr. Bernard Fisher and the first National Surgical Adjuvant Breast and Bowel Project trial in 1971, the field of breast surgery underwent significant growth over the next several decades, enabling general surgeons to limit their practices to the breast. High surgical volumes eventually led to the development of the first formal breast surgical oncology fellowship in a large community-based hospital at Baylor University Medical Center in 1982. The establishment of the American Society of Breast Surgeons, as well several landmark clinical trials and public campaign efforts, further contributed to the advancement of breast surgery, making it the specialized field of the current era.

Keywords: breast cancer, breast fellowship, breast surgery, surgical history

Procedia PDF Downloads 141

Authors: John Saaka

Abstract:

The increasing world population poses a threat to food security. To meet current and future food demands, sweetpotato stand a good chance because of its recent food security roles. Concerted efforts are needed for both regional and local level varietal development. Heterosis exploiting breeding scheme (HEBS) is one of the options used to improve yield in some crop species and could be a good approach for sweetpotato improvement in Ghana by establishing heterotic gene pools within a population. To achieve this, 22 parental lines were collected from different sources and put in a full diallel arrangement. A total of 149 families, 20 individual cuttings per family, were taken to the field, including ‘checks’ and parental lines for experimentation in a 1m X 0.3m planting order according to the Westcott design. Results from this study led to the characterization of the selected parents into three main heterotic gene pools based on their suitability for use as male, female or both, respectively. This study serves as a baseline for further characterization of the rest of the germplasm in the Ghanaian sweetpotato breeding program.

Keywords: sweetpotato, heterosis, germplasm, food security

Procedia PDF Downloads 80

Authors: I. Coxhill, P. Stiles, R. Westcott

Abstract:

This paper provides a comprehensive overview of the LEROS 4 high-thrust apogee engine, intended for use on interplanetary spacecraft. The LEROS 4 rocket engine is a nominal 1.05 kN thrust engine, burning MMH and MON-3 with an Isp of >317s. The engine can be considered an enhanced thrust version of the conventional ~400N apogee engines used on many telecommunication platforms. The motivation for the development of this engine was the need for high-performance, high-thrust propulsion, particularly where gravity losses are high - typical of interplanetary maneuvers. There are a limited number of commercially available engines in the ~1kN class with a high specific impulse. The LEROS 4 engine aimed to fill this gap and provide a flexible engine for high-thrust applications. Two variants of the engine were developed out of the main programme: the LEROS 4 and the LEROS 4-ET. Whilst the LEROS 4 has a nominal thrust of 1.05kN, the ET (Extended Thrust) version operates at a nominal 1.31 kN, albeit at higher inlet pressure. This paper charts the design and development of the engine through the initial concepts, hot fire testing at sea level, hot fire testing at altitude, all the way through to engine qualification for ESA (European Space Agency). In addition to the engine itself, the test facilities in which the engine is tested are discussed. As the LEROS 4 has an unusual thrust level, there are few facilities in the world that can efficiently test an engine at this thrust level. Accordingly, Nammo designed and built a vacuum test facility that allows testing up to 1.5kN of thrust to accommodate the LEROS 4 program. Some unique features of this test facility are explained in the paper. The paper also discusses the in-flight experience of the inaugural flight (the LEROS 4-ET on board the Firefly Blue Ghost lunar lander) and the ongoing LEROS-4 qualification program for ESA, targeted at the EnVision mission to Venus. Finally, the paper summarises the achievements to date and presents a detailed specification of the performance capability.

Keywords: apogee, hypergolic, interplanetary, MMH, MON-3, rocket engine, spacecraft

Procedia PDF Downloads 2