Tracking Quintessence Would Require Two Cosmic Coincidences

Good tracking requires that the quintessence energy fraction slowly increase while the roll $\lambda\equiv -d\ln V/\varkappa d\phi$ slowly decreases, but is not yet truly slow-rolling. The supernova bound on the present quintessence equation of state requires either (1) a cosmological constant or other fine-tuned "crawling quintessence" or (2) "roll-over quintessence" that tracked until recently, but now became slow rolling, because of a sharp increase in potential curvature. Thus, fine-tuning is required by constant equation of state and inverse power potentials, but can be avoided by the SUGRA and Skordis-Albrecht potentials and other good trackers, provided quintessence energy domination and slow roll {\em both} began only recently. This makes the time in which we live special in {\em two} respects.Comment: 10 pages, including 2 figures, 3 table

Elastic English: A Mission for Writing Centers

University Writing Cente

Observed Smooth Energy is Anthropically Even More Likely As Quintessence Than As Cosmological Constant

For a universe presently dominated by static or dynamic vacuum energy, cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of vacuum energy to clustered mass, \Omega_{Q0}/\Omega_{m0}. Identifying these collapsed fractions as anthropic probabilities, we find the value \Omega_{Q0}/\Omega_{m0} \sim 2 to be reasonably likely in LCDM, and very likely in QCDM.Comment: 4 pages, 2 tables, 1 figur

Fossils: Digging Into the Past

Fossils collected in Renaissance collection cabinets were items of wonder and curiosity. Although sometimes mistaken for other pieces of naturalia, they were widely collected by owners of princely cabinets and scholarly collections.Though naturalists and collectors often kept fossils in their collections, they did not have the same understanding as we do today of what they are. Due to their belief in mythological monsters and naturalia with magical properties, there were often misinterpretations or mislabeled objects to something they were not. According to Kenseth’s “A World of Wonders in One Closet Shut,” some collectors believed that fossilized shark’s teeth were “adders’ tongues,” and that they could be used as antidotes to poison. Just as whale ribs were mistaken for “giant bones,” and narwhal tusks were mistaken for “unicorn horns,” fossils were also often misunderstood. [excerpt

Public Accountability of Advisory Committees

The final paper from the symposium on public participation in Risk management discusses existing procedures for ensuring the integrity of advisory committee recommendations. It concludes that they are inadequate and argues that accountability would be better served if nonexperts were included. It also suggests that, in any event, measures need to be taken to indicate, e.g., the bases for committee conclusions

Method of recertifying a loaded bearing member

A method is described of recertifying a loaded bearing member using ultrasound testing to compensate for different equipment configurations and temperature conditions. The standard frequency F1 of a reference block is determined via an ultrasonic tone burst generated by a first pulsed phased locked loop (P2L2) equipment configuration. Once a lock point number S is determined for F1, the reference frequency F1a of the reference block is determined at this lock point number via a second P2L2 equipment configuration to permit an equipment offset compensation factor Fo1=((F1-F1a)/F1)(1000000) to be determined. Next, a reference frequency F2 of the unloaded bearing member is determined using a second P2L2 equipment configuration and is then compensated for equipment offset errors via the relationship F2+F2(Fo1)/1000000. A lock point number b is also determined for F2. A resonant frequency F3 is determined for the reference block using a third P2L2 equipment configuration to determine a second offset compensation factor F02=((F1-F3)/F1) 1000000. Next the resonant frequency F4 of the loaded bearing member is measured at lock point number b via the third P2L2 equipment configuration and the bolt load determined by the relationship (-1000000)CI(((F2-F4)/F2)-Fo2), wherein CI is a factor correlating measured frequency shift to the applied load. Temperature compensation is also performed at each point in the process