Perturbative Expansion around the Gaussian Effective Action: The Background Field Method

We develop a systematic method of the perturbative expansion around the Gaussian effective action based on the background field method. We show, by applying the method to the quantum mechanical anharmonic oscillator problem, that even the first non-trivial correction terms greatly improve the Gaussian approximation.Comment: 16 pages, 3 eps figures, uses RevTeX and epsf. Errors in Table 1 are corrected and new references are adde

Helminth parasites of cats from the Vientiane Province, Laos, as indicators of the occurrence of causative agents of human parasitoses

A total of 55 domestic cats (Felis calus f. domestico) and one wild (Bengal) cat (Prionailurus bengalensis) from the Vientiane Province, central Laos, were examined for helminth parasites with emphasis given to potential human parasites. The following species were found (parasites infective to man marked with an asterisk): Opisthorchis viverrini*, Haplorchis pumilio*,H. laichui*,H. yokogawai*, Stellantchasmus falcatus* (Digenea); Spirometra sp.*, Dipylidium caninum*, Taenia taeniaeformis (Cestoda); Capillariidae gen. sp., Toxocara canis*, T. cati*, Ancylostoma ceylanicum*, A. tubaeforme, Gnathostoma spinigerum*, Physaloptera preputials (Nematoda); and Oncicola sp. (Acanthocephala). This study demonstrated that examination of cats may provide useful data on the occurrence of helminths which are potential causative agents of human diseases

Study on the surface morphology of the developmental stages of the liver fluke,

The external morphology of some developmental stages of the fluke Opisthorchis viverrini (Trematoda: Opisthorchiidae), parasitizing humans in Southeast Asia was studied for the first time using electron microscopy. The surface structure of the egg, as well as the rediae, cercaria, metacercaria, and adult found in naturally infected hosts from Laos are described herein and their morphological characteristics discussed