Front Surface Recording Reliability Studies

Abstract

Data from future high precision cosmic microwave background measurements will be sensitive to the primordial helium abundance Y p . At the same time, this parameter can be predicted from big bang nucleosynthesis (BBN) as a function of the baryon and radiation densities, as well as a neutrino chemical potential. We suggest using this information to impose a self-consistent BBN prior on Y p and determining its impact on parameter inference from simulated planck data. We find that this approach can significantly improve bounds on cosmological parameters compared to an analysis which treats Y p as a free parameter, if the neutrino chemical potential is taken to vanish. We demonstrate that fixing the helium fraction at an arbitrary value can seriously bias parameter estimates. Under the assumption of degenerate BBN (i.e., letting the neutrino chemical potential ξ vary), the BBN prior's constraining power is somewhat weakened, but nevertheless allows us to constrain ξ with an accuracy that rivals that for bounds inferred from present data on light element abundances.

An increased capacity DataPlay optical disc and drive

“…The channel data rate is 20MHz, using EFM+ encoding and an enhanced ECC block format that provides superior correction capabilities to that used on DVD 5 . In order to keep the channel data rate the same with the higher linear bit density, the scan velocity is reduced from 2.9 meters per second to 2.386 meters per second.…”

“…The 32mm small form-factor optical disc and drive from DataPlay have been described before 1,2,3,4,5,6 . The original model of the DataPlay disc and drive were designed for target markets like MP3 digital music players, digital still cameras, USB storage devices, etc.…”

A Biometric Access Personal Optical Storage Device

“…The DataPlay 32 mm diameter small form factor optical storage media and drive have been described previously (1)(2)(3)(4)(5)(6) as has the PassPlay digital password protection scheme (7,8) that permits content security and media inter-changeability through the storage of encrypted passwords on the media itself. In this new implementation the small form factor optical engine has been embedded into a stand alone USB 2.0 based system that is 65mm by 67mm by 20mm.…”