DEVELOPMENT OF SYSTEMIC INSECTICIDES FOR PESTS OF ANIMALS IN THE UNITED STATES1

The first encouraging results in the search for systemic insecticides were obtained in 1944 by Lindquist and his co-workers (53), who found that bed bugs, Cimex lectularius Linnaeus and C. hemipterus (Fabricius), died after feeding on rabbits treated orally with DDT or pyrethrins. In 1946, Knipling and associates (48) treated rabbits with oral and intravenous dosages of insecticides,and reported that rabbits tolerated treatments of lindane and 2 -pivalyl-I,3-indandione at rates that were lethal to mosquitoes, Aedes aegypti (Linnaeus), and human body lice, Pediculus humanus humanus Linnaeus when feeding on the rabbits. These findings, made at the Orlando, Florida, laboratory of the United States Department of Agriculture in conjunction with wartime research on the development of military insecticides, justified the initiation of a project on animal systemic insecticides at the Kerrville, Texas, Livestock Insects Laboratory. Since that date, en­tomologists at Kerrville have worked intensively, screening candidate ma­terials in the laboratory and conducting small-scale field tests with promising compounds. Concurrent toxicological observations have been made by co­ operating veterinarians of the Animal Disease and Parasite Research Divi­sion, and analyses of residues of insecticides in meat and milk have been made by cooperating chemists of the Pesticide Chemicals Research Branch of the Entomology Research Division. A description of steps in the development of the first practical systemic insecticide by the cooperative effort of entomologists, veterinarians, and chemists, both in the U. S. Department of Agriculture and from other or­ganizations and industry, is presented below

Camera distortion self-calibration using the plumb-line constraint and minimal Hough entropy

In this paper we present a simple and robust method for self-correction of camera distortion using single images of scenes which contain straight lines. Since the most common distortion can be modelled as radial distortion, we illustrate the method using the Harris radial distortion model, but the method is applicable to any distortion model. The method is based on transforming the edgels of the distorted image to a 1-D angular Hough space, and optimizing the distortion correction parameters which minimize the entropy of the corresponding normalized histogram. Properly corrected imagery will have fewer curved lines, and therefore less spread in Hough space. Since the method does not rely on any image structure beyond the existence of edgels sharing some common orientations and does not use edge fitting, it is applicable to a wide variety of image types. For instance, it can be applied equally well to images of texture with weak but dominant orientations, or images with strong vanishing points. Finally, the method is performed on both synthetic and real data revealing that it is particularly robust to noise.Comment: 9 pages, 5 figures Corrected errors in equation 1

Model study on the photoassociation of a pair of trapped atoms into an ultralong-range molecule

Using the method of quantum-defect theory, we calculate the ultralong-range molecular vibrational states near the dissociation threshold of a diatomic molecular potential which asymptotically varies as $-1/R^3$. The properties of these states are of considerable interest as they can be formed by photoassociation (PA) of two ground state atoms. The Franck-Condon overlap integrals between the harmonically trapped atom-pair states and the ultralong-range molecular vibrational states are estimated and compared with their values for a pair of untrapped free atoms in the low-energy scattering state. We find that the binding between a pair of ground-state atoms by a harmonic trap has significant effect on the Franck-Condon integrals and thus can be used to influence PA. Trap-induced binding between two ground-state atoms may facilitate coherent PA dynamics between the two atoms and the photoassociated diatomic molecule.Comment: 11 pages, 4 figures, to appear in Phys. Rev. A (September, 2003