9,575 research outputs found
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
A study of the break-up characteristics of Chena River Basin using ERTS imagery
The author has identified the following significant results. The Chena River Basin was selected because of the availability of ground truth data for comparison. Very good agreement for snow distribution and rates of ablation was found between the ERTS-1 imagery, the snowmelt model, and field measurements. Monitoring snowmelt rates for relatively small basins appears to be practical. The main limitation of the ERTS-1 imagery is the interval of coverage. More frequent overflights providing coverage are needed for the study of transient hydrologic events. ERTS-1 data is most useful when used in conjunction with snowmelt prediction models and existing snow course data. These results should prove very useful in preliminary assessment of hydrologic conditions in ungaged watersheds and will provide a tool for month-to-month volume forecasting
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