D-branes on Orbifolds and Topology Change

We consider D-branes on an orbifold $C^3/Z_n$ and investigate the moduli space of the D-brane world-volume gauge theory by using toric geometry and gauged linear sigma models. For $n=11$, we find that there are five phases, which are topologically distinct and connected by flops to each other. We also verify that non-geometric phases are projected out for $n=7,9,11$ cases as expected. Resolutions of non-isolated singularities are also investigated.Comment: 21 pages + 12 eps figures, LaTeX, minor correction

Stability and reactivity of dimethylethoxysilane

The chemistry of the compound dimethylethoxysilane (DMES) is discussed especially as it relates to waterproofing silica surfaces. Some of the desirable properties of this compound are that it readily reacts with silica in the vapor phase, it is a low boiling point liquid (54 C), and the by-product of its reaction with silica is the rather inert substances ethanol. It is currently used by NASA to re-waterproof the HRSI shuttle tiles before relaunching the vehicle. Very little information is available on this particular compound in the literature or even on related silane compounds that have both a hydride group and an alkoxy group. Since the close proximity of two groups often drastically affects the chemical behavior of each group, chemical reactions were carried out in the laboratory with DMES to verify the expected behavior of these two functional groups located on DMES. Some of the reactions tested would be potentially useful for quantitative or qualitative measurements on DMES. To study the reactions of DMES with silica surfaces, cabosil was used as a silica substrate because of its high surface area and the ease of detection by infrared spectroscopy as well as other techniques

D-brane gauge theories from toric singularities of the form C3/ΓC^3/\Gamma and C4/ΓC^4/\Gamma

We discuss examples of D-branes probing toric singularities, and the computation of their world-volume gauge theories from the geometric data of the singularities. We consider several such examples of D-branes on partial resolutions of the orbifolds ${\bf C^3/Z_2\times Z_2}$,${\bf C^3/Z_2\times Z_3}$ and ${\bf C^4/Z_2\times Z_2 \times Z_2}$.Comment: 34+1 pages, References added, Version to appear in Nuclear Physics

Oral History Interview: Douglas Johnson

This interview is one of a series conducted concerning West Virginia Vietnam veterans. Douglas Johnson discusses: his education, personal history, and family; enlisting in the Marines; boot camp and his military training; other officers; Advanced Infantry Training; an incident during his guard duty; his experiences in Vietnam; and other topics.https://mds.marshall.edu/oral_history/1322/thumbnail.jp

Review of \u3ci\u3eThe Duck Factory: A History of Waterfowl in North Dakota,\u3c/i\u3e by Mike Jacobs and Erik Fritzell

It was by geological accident that North Dakota became the heart of duck production in the continental United States. When the Wisconsin glaciation retreated some 11,000 years ago, it left an uneven layer of glacial till over much of North Dakota and nearby states and provinces, an area termed the Prairie Pothole Region. Large blocks of ice in the glacial till eventually melted and formed depressions that became wetlands, or prairie potholes. These were embedded in a matrix of soil that, with millennia of growth by deep-rooted prairie plants, became rich topsoil. The wetlands, surrounded by luxuriant grassland, were ideal places for waterfowl to breed. The rich soils of the uplands also offered attractive areas for agriculture. The interplay and conflicts between waterfowl and agriculture drove much of the history of waterfowl in North Dakota during the past century and a half. The Duck Factory: A History of Waterfowl in North Dakota tells the story well. Many photographs, usually historic, grace the pages of the book