Bounding the mass of the graviton using binary pulsar observations

The close agreement between the predictions of dynamical general relativity for the radiated power of a compact binary system and the observed orbital decay of the binary pulsars PSR B1913+16 and PSR B1534+12 allows us to bound the graviton mass to be less than 7.6 x 10^{-20} eV with 90% confidence. This bound is the first to be obtained from dynamic, as opposed to static-field, relativity. The resulting limit on the graviton mass is within two orders of magnitude of that from solar system measurements, and can be expected to improve with further observations.Comment: 16 pages, 1 figure. Added appendix on other choices for mass ter

Swift Pointing and Gravitational-Wave Bursts from Gamma-Ray Burst Events

The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar-mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit this model to be tested. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. This requires joint observations of gamma-ray burst events with gravitational and gamma-ray detectors. Here we examine how the quality of an upper limit on the gravitational-wave strength associated with gamma-ray bursts depends on the relative orientation of the gamma-ray-burst and gravitational-wave detectors, and apply our results to the particular case of the Swift Burst-Alert Telescope (BAT) and the LIGO gravitational-wave detectors. A result of this investigation is a science-based ``figure of merit'' that can be used, together with other mission constraints, to optimize the pointing of the Swift telescope for the detection of gravitational waves associated with gamma-ray bursts.Comment: iop style, 1 figure, 6 pages, presented at GWDAW 200

Functional relations modulate the responsiveness to affordances despite the impact of conflicting stimulus-response mappings

The study investigated how conflicting stimulus-response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent-inconsistent stimulus-response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could functionally match (e.g., Kitchen- Spatula) or not (e.g., Kitchen- Hammer), as well as the spatial relations (e.g., a match or a mismatch between participants' hand response and the tool-object orientation). The results showed faster reaction times (RTs) when functional relations between stimuli matched both in consistent and inconsistent blocks. Differences in RTs and accuracy between consistent and inconsistent blocks were only found when the functional relation between stimuli matched. No modulation of the performance was observed for mismatching functional relations and spatial relations between blocks. These results support the hypothesis that the responsiveness to affordances is strongly modulated by matching functional relations, despite the impact of conflicting stimulus-response mappings

Dynamics of the trade balance and the terms of trade: the S-curve

We provide a theoretical interpretation of two features of international data: the countercyclical movements in net exports and the tendency for the trade balance to be negatively correlated with current and future movements in the terms of trade, but positively correlated with past movements. We document these same properties in a two-country stochastic growth model in which trade fluctuations reflect, in large part, the dynamics of capital formation. We find that the general equilibrium perspective is essential: The relation between the trade balance and the terms of trade depends critically on the source of fluctuations.Balance of trade

Relative price movements in dynamic general equilibrium models of international trade

We examine the behavior of international relative prices from the perspective of dynamic general equilibrium theory, with particular emphasis on the variability of the terms of trade and the relation between the terms of trade and net exports. We highlight aspects of the theory that are critical in determining these properties, contrast our perspective with those associated with the Marshall-Lerner condition and the Harberger-Laursen-Metzler effect, and point out features of the data that have proved difficult to explain within existing dynamic general equilibrium models.International trade

Swift Pointing and the Association Between Gamma-Ray Bursts and Gravitational-Wave Bursts

The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit this model to be tested, the black hole progenitor (e.g., coalescing binary or collapsing stellar core) identified, and the origin of the gamma rays (within the expanding relativistic fireball or at the point of impact on the interstellar medium) located. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. To do any of these requires joint observations of gamma-ray burst events with gravitational and gamma-ray detectors. Here we examine how the quality of an upper limit on the gravitational-wave strength associated with gamma-ray burst observations depends on the relative orientation of the gamma-ray-burst and gravitational-wave detectors, and apply our results to the particular case of the Swift Burst-Alert Telescope (BAT) and the LIGO gravitational-wave detectors. A result of this investigation is a science-based ``figure of merit'' that can be used, together with other mission constraints, to optimize the pointing of the Swift telescope for the detection of gravitational waves associated with gamma-ray bursts.Comment: aastex, 14 pages, 2 figure

Prospectus, April 8, 2004

https://spark.parkland.edu/prospectus_2004/1009/thumbnail.jp