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The recent discovery of a Gunn–Peterson (GP) trough in the spectrum of the redshift 6.28 SDSS quasar has raised the tantalizing possibility that we have detected the reionization of the universe. However, a neutral fraction (of hydrogen) as small as 0.1% is sufficient to cause the GP trough, hence its detection alone cannot rule out reionization at a much(More)
We present a method for reducing cosmological data to constraints on the amplitudes of modes of the dark energy density as a function of redshift. The modes are chosen so that 1) one of them has constant density and 2) the others are non-zero only if there is time-variation in the dark energy density and 3) the amplitude errors for the time-varying modes(More)
The normal parameters are a non–linear transformation of the cosmological parameters whose likelihood function is very well–approximated by a normal distribution. This transformation serves as an extreme form of data compression allowing for practically instantaneous calculation of the likelihood of any given model, as long as the model is in the parameter(More)
We have developed a correlation microscopy technique to follow the dynamics of quantum dot labeled DNA within living cells. The temporal correlation functions of the labels reflect the fluctuations of the DNA nanoprobe as a result of its interactions with the cellular environment. They provide a sensitive measure for the length of the probe on the scale of(More)
Implementation of a silicon germanium (SiGe) field programmable gate array (FPGA) has been described. The reconfigurable basic cell (BC) that evolved from the Xilinx XC6200 has been redesigned to achieve high speed with lower power consumption. The propagation delay of the BC in comparison to the BC implemented in the earlier generation SiGe process has(More)
Cosmological parameters affect observables in physically distinct ways. For example, the baryon density, ωb, affects the ionization history and also the pressure of the pre-recombination fluid. To investigate the relative importance of different physical effects to the determination of ωb, and to test the cosmological model, we artificially split ωb into(More)
Forty years ago Gene Amdahl published a figure of merit for parallel computation, which proved extremely controversial. The controversy still rages today, although those that have looked closely at this figure of merit conclude that it is correct, but perhaps misinterpreted. In this paper we will look at a small variation on that law that suggests computer(More)