Spinodal Backreaction During Inflation and Initial Conditions

We investigate how long wavelength inflationary fluctuations can cause the background field to deviate from classical dynamics. For generic potentials, we show that, in the Hartree approximation, the long wavelength dynamics can be encapsulated by a two-field model operating in an effective potential. The latter is given by a simple Gaussian integral transformation of the original inflationary potential. We use this new expression to study backreaction effects in quadratic, hilltop, flattened, and axion monodromy potentials. We find that the net result of the altered dynamics is to slightly modify the spectral tilt, drastically decrease the tensor-to-scalar ratio, and to effectively smooth over any features of the potential, with the size of these deviations set by the initial value of power in large scale modes and the shape of the potential during the entire evolution.Comment: 30 pages, 8 figure

Information Revelation in Auctions.

Auction theory has emphasized the importance of private information to the profits of bidders. However, the theory has failed to consider the question of whether or not bidders will be able to keep their information private. We show that in a variety of contexts bidders will reveal all their information, even if this information revelation is (ex ante) detrimental to them. Similarly, a seller may reveal all her information even when this revelation lowers revenues. We also show that bidders may be harmed by private information.WINNERS CURSE; LINKAGE PRINCIPLE; REVELATION BY BIDDERS

Photosynthetic Gas Exchange in the Closed Ecosystem for Space. Phase II, Part III. Screening for Thermophilic Algae and Mutation Studies

An algal screening and mutation study was undertaken to obtain algae superior to Chlorella 71105 for use in a photosynthetic gas exchanger. Of the forty-four thermophilic algae studied, eighteen appeared to have growth rates as great as Chlorella 71105. Optimization of the physical and chemical environments of these strains is recommended as a way to further improve growth rates and concomitant oxygen production. The mutation study revealed that Chlorella 71105 is relatively resistant to germicidal ultraviolet radiation. No high temperature mutants of Chlorella 71105 were found

1/fα1/f^\alpha spectra in elementary cellular automata and fractal signals

We systematically compute the power spectra of the one-dimensional elementary cellular automata introduced by Wolfram. On the one hand our analysis reveals that one automaton displays $1/f$ spectra though considered as trivial, and on the other hand that various automata classified as chaotic/complex display no $1/f$ spectra. We model the results generalizing the recently investigated Sierpinski signal to a class of fractal signals that are tailored to produce $1/f^{\alpha}$ spectra. From the widespread occurrence of (elementary) cellular automata patterns in chemistry, physics and computer sciences, there are various candidates to show spectra similar to our results.Comment: 4 pages (3 figs included