| rotational grazing for control of gastrointestinal nematodes of goats in a wet tropical environment. | a preliminary experiment involving contamination of pasture plots with eggs of haemonchus contortus, trichostronglyus colubriformis and oesophagostomum columbianum every month for a year established that in the tropical environment of the pacific island of tongatapu, hatching and development of all species was rapid and continuous, with a short survival on pasture (3-7 weeks) of the resulting infective larvae. these results indicated that a rotational grazing system consisting of ten paddocks gr ... | 1994 | 8091608 |
| geographic components of linkage disequilibrium in natural populations of escherichia coli. | geographic variation in the genetic structure of natural enteric populations of escherichia coli was assessed at both the single-locus and dilocus levels from allozyme genotypes at 12 enzyme loci in 178 cell lines isolated from human hosts in sweden, iowa, and tonga. although there was significant heterogeneity in allele frequencies at six of the 12 loci, geographic variation accounted for only 2.0% of the total genetic diversity (ht = 0.518). ohta's d-statistics were used to partition the total ... | 1983 | 6400648 |