D Branes and Textures

We examine the flavor structure of the trilinear superpotential couplings which can result from embedding the Standard Model within D brane sectors in Type IIB orientifold models, which are examples within the Type I string framework. We find in general that the allowed flavor structures of the Yukawa coupling matrices to leading order are given by basic variations on the "democratic" texture ansatz. In certain interesting cases, the Yukawa couplings have a novel structure in which a single right-handed fermion couples democratically at leading order to three left-handed fermions. We discuss the viability of such a ``single right-handed democracy'' in detail; remarkably, even though there are large mixing angles in the u,d sectors separately, the CKM mixing angles are small. The analysis demonstrates the ways in which the Type I superstring framework can provide a rich setting for investigating novel resolutions to the flavor puzzle.Comment: 23 pages, references adde

Engineering a Successful Mission: Lessons from the Lunar Reconnaissance Orbiter

Schedule pressure is common in the commercial world, where late delivery of a product means delayed income and loss of profit. 12 Research spacecraft developed by NASA, on the other hand, tend to be driven by the high cost of launch vehicles and the public scrutiny of failure-- the primary driver is ensuring proper operation in space for a system that cannot be retrieved for repair. The Lunar Reconnaissance Orbiter (LRO) development faced both schedule pressure and high visibility. The team had to balance the strong push to meet a launch date against the need to ensure that this first mission for Exploration succeeded. This paper will provide an overview of the mission from concept through its first year of operation and explore some of the challenges the systems engineering team faced taking a mission from preliminary design review to pre-ship review in 3 years

Index of Everett Greaton Early Maine Travel Films and Home Movies

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Remarks and Photographs from Androscoggin Historical Society Program: Everett F. Greaton Tourism Films 2012

https://digitalmaine.com/greaton_docs/1000/thumbnail.jp

Greaton Family Scrapbook

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