Waveforms for Gravitational Radiation from Cosmic String Loops

We obtain general formulae for the plus- and cross- polarized waveforms of gravitational radiation emitted by a cosmic string loop in transverse, traceless (synchronous, harmonic) gauge. These equations are then specialized to the case of piecewise linear loops, and it is shown that the general waveform for such a loop is a piecewise linear function. We give several simple examples of the waveforms from such loops. We also discuss the relation between the gravitational radiation by a smooth loop and by a piecewise linear approximation to it.Comment: 16 pages, 6 figures, Revte

The graviton propagator in homogeneous and isotropic spacetimes

We find the propagator for gravitons in spacetimes with homogeneous and isotropic flat (k=0) spatial sections. The method also applies to the k = + 1 and K = −1 cases. The vacuum state is assumed to be homogeneous and isotropic in the same way as the spacetime. In the four most interesting physical cases, which are de Sitter space, the radiation and dust dominated models, and flat space, we obtain the graviton propagator in closed form for the adiabatic vacuum state

Modularity of nearly ordinary 2-adic residually dihedral Galois representations

We prove modularity of some two dimensional, 2-adic Galois representations over totally real fields that are nearly ordinary and that are residually dihedral. We do this by employing the strategy of Skinner and Wiles, using Hida families, together with the 2-adic patching method of Khare and Wintenberger. As an application we deduce modularity of some elliptic curves over totally real fields that have good ordinary or multiplicative reduction at places above 2.Comment: 87 pages. Typos correcte

Nonhazardous acid etches weld samples

Nonhazardous citric acid solution used with 24 volt dc power supply etches weld samples. This etching method is limited to 300 stainless steel and a small range of other high temperature alloys

Semiconductors can be tested without removing them from circuitry

Oscilloscope, with specially developed test circuitry, quickly checks semiconductors without removing them from the circuitry. For transistors, approximate gain and linearity, as well as PNP or NPN determinations are made. When testing diodes, open or short circuits, and reverse polarity show up plainly

Toward an Interactive Directory for Norfolk, Nebraska: 1899-1900

We describe steps toward an interactive directory for the town of Norfolk, Nebraska for the years 1899 and 1900. This directory would extend the traditional city directory by including a wider range of entities being described, much richer information about the entities mentioned and linkages to mentions of the entities in material such as digitized historical newspapers. Such a directory would be useful to readers who browse the historical newspapers by providing structured summaries of the entities mentioned. We describe the occurrence of entities in two years of the Norfolk Weekly News, focusing on several individuals to better understand the types of information which can be gleaned from historical newspapers and other historical materials. We also describe a prototype program which coordinates information about entities from the traditional city directories, the federal census, and from newspapers. We discuss the structured coding for these entities, noting that richer coding would increasingly include descriptions of events and scenarios. We propose that rich content about individuals and communities could eventually be modeled with agents and woven into historical narratives