What Do We Really Know About Cosmic Acceleration?

Essentially all of our knowledge of the acceleration history of the Universe - including the acceleration itself - is predicated upon the validity of general relativity. Without recourse to this assumption, we use SNeIa to analyze the expansion history and find (i) very strong (5 sigma) evidence for a period of acceleration, (ii) strong evidence that the acceleration has not been constant, (iii) evidence for an earlier period of deceleration and (iv) only weak evidence that the Universe has not been decelerating since z~0.3.Comment: 9 pages, 8 figure

Drag Coefficients of Varying Dimple Patterns

There are many golf balls on the market today with varying dimple sizes, shapes, and distribution. These proprietary differences are all designed to reduce drag on the balls during flight. There are limited published studies comparing how varying the dimples affects the reduction of drag. An experiment was developed in which golf balls were pulled through a water tank to measure the drag force acting on each ball. The water was chosen to allow for testing at slower velocities. A range of dimple patterns were tested and compared to determine which pattern has the lowest associated drag coefficient

Positivity and topology in lattice gauge theory

The admissibility condition usually used to define the topological charge in lattice gauge theory is incompatible with a positive transfer matrix.Comment: 6 pages, revtex; revision has some clarifications and additional references, representing the final version to appear in Physical Revie