Making electromagnetic wavelets

Electromagnetic wavelets are constructed using scalar wavelets as superpotentials, together with an appropriate polarization. It is shown that oblate spheroidal antennas, which are ideal for their production and reception, can be made by deforming and merging two branch cuts. This determines a unique field on the interior of the spheroid which gives the boundary conditions for the surface charge-current density necessary to radiate the wavelets. These sources are computed, including the impulse response of the antenna.Comment: 29 pages, 4 figures; minor corrections and addition

A low-frequency radio survey of the planets with RAE-2

Over one thousand occultations of each planet in the solar system have occurred during the period from mid-1973 through mid-1976 as seen from the lunar orbiting Radio Astronomy Explorer-2 (RAE-2) spacecraft. These occultations have been examined for evidence of planetary radio emissions in the 0.025 to 13.1 MHz band. Only Jupiter and the earth have given positive results. Lack of detection of emission from the other planets can mean that either they do not emit radio noise in this band or the flux level of their emissions and/or its occurrence rate are too low to be detected by RAE-2

Solution of Einstein’s Causality Problem: The AHK Theorem

'Chance' is defined as an event on the time scale withour any cause before it appears. That means, that cause and effect is identical. This is the only way to integrate chance into a consistent theory of causality. The identity of cause and effect is called AHK theorem (Aristotle-Hegel-Kaiser)

The solar elogation distribution of low frequency radio bursts

Over 500 days of low frequency (less than 5 MHz) radio observations from the IMP-6 spacecraft were accumulated to produce a two dimensional map (frequency versus elongation) of solar type III burst occurrences. This map indicates that most solar bursts are emitted at the second harmonic of the plasma frequency rather than the fundamental. The map also shows that the solar wind electron density varies

MARKET IMPACTS OF BOVINE SOMATROPIN: A SUPPLY AND DEMAND ANALYSIS

The potential economic impacts of the introduction of bovine somatotropin (bST) on U.S. milk supply and demand are analyzed using a national model of Class I and Class II milk markets. The results indicate that the introduction of bST will lead to lower milk prices, higher milk production, and larger government purchases of dairy products. Unlike previous economic analyses of bST, this analysis considers both supply and demand effects of bST. The implication is that studies that ignore potential demand-side effects may produce misleading results.Demand and Price Analysis,

AN ANNOTATIVE BIBLIOGRAPHY OF RESEARCH ON THE ECONOMIC EFFECTS OF CLIMATE CHANGE ON AGRICULTURE

Anthropogenic emissions of carbon dioxide and other "greenhouse" gases have the potential to substantially warm climates worldwide. While the timing and magnitude of global warming is uncertain, scientists on the Intergovernmental Panel on Climate Change (IPCC) predict that average global temperature may increase by 1.5- 4.5³C (2.7-8.1³F) over the next 100 years. Changes in precipitation will likely accompany any changes in temperature. However, the magnitude, and even direction of these changes is difficult to predict with much confidence on a regional basis. The agricultural sector may be profoundly affected by future changes in temperature, precipitation, solar radiation, and carbon dioxide concentrations. Over the past decade, there has been a growing body of research examining the potential impacts of climate change on agriculture. The purpose of this paper is to report and summarize recent research on the potential economic impacts of global climate change on agriculture. To that end, an annotative bibliography of articles is presented in this paper.Environmental Economics and Policy,

EDUCATIONAL FINANCE IN MINNESOTA: AN EXAMINATION OF THE FOUNDATION AID PROGRAM

Public Economics,

Dominant 2πγ2\pi\gamma-exchange nucleon-nucleon interaction: Spin-spin and tensor potentials

We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the two-pion exchange nucleon-nucleon interaction that is generated by the isovector spin-flip $\pi\pi NN$ contact-vertex proportional to the large low-energy constant $c_4\simeq 3.4$GeV$^{-1}$. We find that the respective $2\pi\gamma$-exchange potentials contain sizeable isospin-breaking components which reach up to -4% of corresponding isovector $2\pi$-exchange potentials. The typical values of these novel charge-independence breaking spin-spin and tensor potentials are $-0.11$MeV and $0.09$MeV, at a nucleon distance of $r=m_\pi^{-1}=1.4$fm. The charge-symmetry breaking spin-spin and tensor potentials come out a factor of 2.4 smaller. Our analytical results for these presumably dominant isospin-violating spin-spin and tensor NN-forces are in a form such that they can be easily implemented into phase-shift analyses and few-body calculations.Comment: 7 pages, 1 figure, 2 tables, to be published in Physical Review C: Brief report

Electromagnetic corrections to the dominant two-pion exchange nucleon-nucleon potential

We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the dominant two-pion exchange nucleon-nucleon interaction that is generated by the isoscalar $\pi N$ contact-vertex proportional to the large low-energy constant $c_3$. We find that the respective $2\pi\gamma$-exchange potential contains sizeable isospin-breaking components which amount to about -1% of the strongly attractive isoscalar central $2\pi$-exchange potential. The typical value of these novel charge-independence and charge-symmetry breaking central potentials is $0.3$MeV at a nucleon distance of $r= m_\pi^{-1} = 1.4$fm. Our analytical result for this presumably dominant $2\pi\gamma$-exchange interaction is in a form such that it can be easily implemented into phase-shift analyses and few-body calculations.Comment: 7 pages, 1 figure, to be published in Physical Review C (2006): Brief Report

Decay dynamics in the coupled-dipole model

Cooperative scattering in cold atoms has gained renewed interest, in particular in the context of single-photon superradiance, with the recent experimental observation of super-and subradiance in dilute atomic clouds. Numerical simulations to support experimental signatures of cooperative scattering are often limited by the number of dipoles which can be treated, well below the number of atoms in the experiments. In this paper, we provide systematic numerical studies aimed at matching the regime of dilute atomic clouds. We use a scalar coupled-dipole model in the low excitation limit and an exclusion volume to avoid density-related effects. Scaling laws for super-and subradiance are obtained and the limits of numerical studies are pointed out. We also illustrate the cooperative nature of light scattering by considering an incident laser field, where half of the beam has a $\pi$ phase shift. The enhanced subradiance obtained under such condition provides an additional signature of the role of coherence in the detected signal