The occurrence of and organisms concerned with bovine mycotic abortion in some counties of Ireland

Bovine mycotic abortion in some counties of the Irish provinces of Leinster and Ulster was estimated at 1–2% of all abortions for which a causal agent was identified in the years from 1969 to 1978. The organism most commonly isolated from diseased specimens wasAspergillus fumigatus, followed byAbsidia corymbifera. There was no relationship between the incidence of the disease in any year and the rainfall or number of raindays during the previous summer. The data obtained are discussed in relation to the occurrence of the disease in the United Kingdom.     

Scanning electron microscopy of the canine atrioventricular bundle and moderator band

The atrioventricular (AV) bundle and the moderator band in the canine heart were examined by scanning electron microscopy. The AV bundle and the moderator band both were comprised of large, cylindrically shaped cells. These cells were highly organized into bundles, with minimal lateral communication between bundles. There was extensive cell-to-cell communication between cells within a bundle. The end branching of individual cells was prominent, with some interbundle communication. These results are discussed in relationship to the electrophysiologic properties of the AV bundle and the conduction velocity.     

Effects of herbicides and herbicide analogs on [14C]leucine incorporation by suspension-cultured Solanum nigrum cells

Assays of [¹⁴C]leucine incorporation were used to measure effects of herbicides on suspensioncultured heterotrophic Solanum nigrum cells. Most herbicidal vs. nonherbicidal chemicals in a set of 47 compounds could be distinguished from each other based on their extent of inhibition of leucine incorporation by S. nigrum cells. Herbicides which failed to inhibit leucine incorporation were photosynthetic inhibitors. Both phytotoxic and nonphytotoxic thiocarbamate analogs (as determined by whole-plant studies) tended to inhibit leucine incorporation. It was concluded that the leucine incorporation screen could detect a majority of compounds tested which are herbicidal, and that it may also be useful to detect compounds which have cellular toxicity which is not observed in the whole plant.     

Management of inappetant sheep during export by sea

In the first of 2 experiments, a simulated voyage was conducted to examine the effects of various treatments on bodyweight change and feeding frequency of inappetant sheep at the end of lot-feeding (non-feeders). The treatments, applied during simulated shipping, were: normal quantities of feed and length of troughs; extra trough length; extra feed. Adult Merino wethers (n = 108) were used in each treatment. A voyage to the Middle East was then conducted to establish whether shipboard mortality could be reduced by separating non-feeders (n = 305) from feeders (n = 5,620) late in the feedlot hase and housing the groups separately aboard ship. A control group of non-feeders (n = 215) mixed with feeders (n = 5,732) was used for comparison. Bars (marker bars), containing a coloured dye, were attached to feed troughs to mark sheep that fed. Most non-feeders (82%) began eating when placed in shipping pens in both studies. However, there was no significant difference in percentage of sheep that fed between non-feeders given extra trough length or extra feed compared with non-feeders given standard management at any stage of simulated shipping. There was no significant difference in mean bodyweights between treatment groups on days 1, 8 and 15 of simulated shipping. Differences in bodyweight on d 22 were probably associated with different levels of gut fill. Death rates were not significantly different in separated and control groups (1.1%, 0.9%, P = 0.6) in the voyage of 14 d to the Middle East.(ABSTRACT TRUNCATED AT 250 WORDS)     

Artificially regenerating longleaf pine in canopy gaps: initial survival and growth during a year of drought

Nitrogen fertilization in the nursery, along with altering the configuration of forest gaps, may improve the reforestation success of longleaf pine seedlings. During the very droughty 1998 growing season in Florida and Georgia, survival was higher under the forest canopy than in small (0.10 ha, 36 m diameter) and large (1.6 ha, 144 m diameter) canopy gaps. In the large gaps, survival of containerized seedlings was higher along the edges, particularly the SW edge. Shade from adult trees and the nurse effect of shrubs increased survival, while grass competition reduced survival. During dry years part of the “exclusionary zone” along the edge of canopy gaps (SW sector) may serve as a “survival zone”, at least in the short term. A model using oval-shaped gaps oriented from NW to SE, with an area of 0.25 ha is proposed to maximize the survival and growth of artificially regenerated longleaf pine seedlings.     

Variation of sapflow velocity in Eucalyptus globulus with position in sapwood and use of a correction coefficient

Sapflow sensors were used to investigate variation in sapflow velocity at different positions in the sapwood of three-year-old Eucalyptus globulus ssp. globulus Labill. trees. Sapflow velocity was measured at 5-mm intervals across the sapwood by moving two probe sets simultaneously on two opposite radii. Another probe set placed in a fixed position at right angles to the first two sets acted as a control. A sapflow velocity ratio was defined as the velocity given by each moving sensor divided by that given by the static sensor. Correlation between observations of sapflow velocity at different positions exceeded 95%, and the ratio of velocity between any pair of sensors was constant. We observed radial variation in sapflow velocity across the sapwood with the lowest velocities at the center of the tree. Variation due to sensor position was high implying the need for large numbers of sensors for accurate estimates of sap flux. To overcome this need, we used a correction coefficient, namely a simple weighted average of the sapflow ratios with depth in the sapwood, for each fixed sensor. We recommend the use of three probe sets to estimate the correction coefficient. Subsequently, two probe sets can be placed at two fixed positions for routine measurements of sap flux.