Bound State Inequality for High Mass Exchanges in a Scalar Field Model

Ladder diagrams are relevant for the study of bound states. The condition upon the coupling strength for the existence of a bound state has been deduced in a scalar field theory for the case of low mass exchanges. We apply this approach to the case of very high mass exchanges.Comment: 14 pages, 3 figure

Gravitational Lensing at Millimeter Wavelengths

With today's millimeter and submillimeter instruments observers use gravitational lensing mostly as a tool to boost the sensitivity when observing distant objects. This is evident through the dominance of gravitationally lensed objects among those detected in CO rotational lines at z>1. It is also evident in the use of lensing magnification by galaxy clusters in order to reach faint submm/mm continuum sources. There are, however, a few cases where millimeter lines have been directly involved in understanding lensing configurations. Future mm/submm instruments, such as the ALMA interferometer, will have both the sensitivity and the angular resolution to allow detailed observations of gravitational lenses. The almost constant sensitivity to dust emission over the redshift range z=1-10 means that the likelihood for strong lensing of dust continuum sources is much higher than for optically selected sources. A large number of new strong lenses are therefore likely to be discovered with ALMA, allowing a direct assessment of cosmological parameters through lens statistics. Combined with an angular resolution <0.1", ALMA will also be efficient for probing the gravitational potential of galaxy clusters, where we will be able to study both the sources and the lenses themselves, free of obscuration and extinction corrections, derive rotation curves for the lenses, their orientation and, thus, greatly constrain lens models.Comment: 69 pages, Review on quasar lensing. Part of a LNP Topical Volume on "Dark matter and gravitational lensing", eds. F. Courbin, D. Minniti. To be published by Springer-Verlag 2002. Paper with full resolution figures can be found at ftp://oden.oso.chalmers.se/pub/tommy/mmviews.ps.g

Making Sense of a Sequence of Events: A Psychologically Supported AI Implementation

International audiencePeople try to make sense of the usually incomplete reports they receive about events that take place. For doing this, they make use of what they believe the normal course of thing should be. An agent's beliefs may be consonant or dissonant with what is reported. For making sense people usually ascribe different types of relations between events. A prototypical example is the ascription of causality between events. The paper proposes a systematic study of consonance and dissonance between beliefs and reports. The approach is shown to be consistent with findings in psychology. An implementation is presented with some illustrative examples

Economics at the FTC: Data Intensive Mergers and Policy R&D

Economics at the Federal Trade Commission (FTC) supports both the competition and consumer protection missions of the agency. In this year’s essay we discuss a range of activities focusing on data-intensive antitrust cases in the hospital and consumer products industries. We also discuss our most recent work on gasoline pricing. Policy-focused research and competition advocacy takes center stage as we discuss some health care advocacy work in the administration of pharmaceutical insurance benefits and efforts to understand the real estate business more completely. Finally, we describe our efforts to quantify the extent of “identity theft”. Copyright Springer Science+Business Media, LLC 2006antitrust, consumer protection, FTC, hospitals, identity theft, mergers, petroleum, pharmaceuticals, real estate,