Daniel Robbins

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1. The ability of rhesus monkeys to detect the gap in Landolt ring test-objects that were presented against background luminances between 5 x 10(-5) cd/m(2) and 5 x 10(3) cd/m(2) was compared with similar human data.2. At high luminance-levels the acuity of human observers is slightly better than that of rhesus, but rhesus have better acuity at scotopic(More)
In a model-independent formalism of gauge mediation, Meade, Seiberg, and Shih have shown that hidden sector effects are captured by two-point correlation functions of the gauge current superfields and that, generically, many of the characteristic features of gauge mediated SUSY breaking do not survive. We review the general story, particularly the way that(More)
We derive several no-go theorems in the context of massive type IIA string theory compactified to four dimensions in a way that, in the absence of fluxes, preserves N = 1 supersymmetry. Our derivation is based on the dilaton, Kähler and complex structure moduli dependence of the potential of the four-dimensional effective field theory, that is generated by(More)
We consider the generation of a non-perturbative superpotential in F-theory compactifications with flux. For models with a single volume modulus, we show that the volume modulus is never stabilized by either abelian instantons or gaugino condensation. We then comment on how our analysis extends to a larger class of compactifications. From our results, it(More)
INTRODUCTION The Invisalign (Align Technology, Santa Clara, Calif) force delivery system has not been investigated. Since forces are related to the strains developed on the aligner surface, the behavior of the maxillary incisor and premolar von Mises strains (IVM, PVM) were studied during biweekly wear of an aligner. METHODS Maxillary aligners (n = 61)(More)
A practical and inexpensive alternative to the standard primate chair is described. The apparatus is designed to allow easy removal of rhesus monkeys from their home cages and to allow restraint without anesthesia. A portable Plexiglas cage, which can be adjusted to accommodate rhesus monkeys of varying sizes, is placed against an animal's home cage. The(More)
We describe the supergravity solutions dual to D6-branes with both time-dependent and time-independent B-fields. These backgrounds generalize the Taub-NUT metric in two key ways: they have asymmetric warp factors and background fluxes. In the time-dependent case, the warping takes a novel form. Kaluza-Klein reduction in these backgrounds is unusual, and we(More)
The null-brane space-time provides a simple model of a big crunch/big bang singularity. A non-perturbative definition of M-theory on this space-time was recently provided using matrix theory. We derive the fermion couplings for this matrix model and study the leading quantum effects. These effects include particle production and a time-dependent potential.(More)