Tile drainage waters from five systematically tiled, commercial potato fields in northwestern New Brunswick were analyzed for the herbicides metribuzin and dinoseb from April 1987 to April 1989. Tile drain outflow rate and volume were also recorded. Dinoseb and metribuzin were detected in tile outflow both during the year of application and during the subsequent spring melt period, but at concentrations substantially less than maximum acceptable concentrations (MAC) for drinking water published by Health and Welfare Canada. Average concentrations of dinoseb twelve months after application ranged from less than the detection limit to 0.21-mu-g.L-1 (five site-years), and the concentration of metribuzin ten months after application averaged 0.22-mu-g.L-1 (one site-year). Persistence of dinoseb in the tile outflow did not appear to be affected by the history of dinoseb use other than those applications occurring within the past 12 months.

AbstractFlow volumes and NO3‐N concentrations of drain discharge from five systematically tiled, commercial potato (Solatium tuberosum L.) fields were measured from April to December, 1987 and 1988, to assess the potential for NO3‐N leaching associated with current production practices. The sites, located in New Brunswick, Canada, ranged from 3 to 10 ha and varied in fertilizer application rate, cropping practices, rainfall, and duration of data collection (the latter due to site access difficulties in the spring). Three of the five sites were representative of intense potato rotations, whereas the remaining two were representative of land conversions into potato production from more passive, low input production systems. Ten site‐years of data were collected. Drain outflow volumes averaged 75 and 115 mm per unit area in 1987 and 1988, respectively. Considerable drain flow occurred during snowmelt each year before data collection began. Measured NO3‐N concentrations ranged from 1 to 65 mg L−1 and there were substantial changes in NO3‐N concentrations within flow events. The flow‐weighted average annual nitrate concentrations of the drainage effluent, , were ≥ 10 mg L−1 for potato site‐years, regardless of whether the sites were established potato rotation fields or not. The concentrations of the established potato rotation sites also remained > 10 mg L−1 for the first non‐potato year following potato. The concentration of one potato rotation site was more than double that of the other two potato rotation sites. Incubation studies showed the soil at this site had considerably more potential to mineralize N than the other two sites. Total NO3‐N leaching for the potato site‐years for the measured April to December periods ranged from 5 to 33 kg N ha−1. More work, under controlled conditions, is required to determine both dormant and growing season NO3‐N leaching associated with various potato production systems.

The effects of over 25 yr of levels of applied N, P and K on forage DM yield, crude protein content, in vitro digestibility (IVD), botanical composition and persistence of a timothy (Phleum pratense L.) sward were assessed in a long-term field experiment on an acidic Riverbank L. Ammonium nitrate (0, 90, 180, 270 kg N ha−1), superphosphate (0, 15, 29, 44 kg P ha−1) and muriate of potash (0, 47, 94, 141 kg K ha−1) were applied annually in all possible combinations to a timothy sward since 1960. In the first 3 yr of the experiment, only N and K were required for maximum yield and persistence of timothy. The requirement for applied P, however, increased with time; in the last 3 yr (1985–1987) of the trial, the highest level of applied P resulted in profitable forage DM yield increases. After 25 yr, the productivity of the timothy sward was dependent upon a balanced application of all three macronutrients; absence of any one nutrient resulted in little or no response to applications of the other nutrients. The long-term persistence of timothy was solely dependent on K fertilization. The proportion of bentgrass and bluegrass species declined with increasing levels of applied K while that of timothy increased. The change in botanical composition due to applied N and K significantly affected IVD and crude protein content.Key words: N, P, K, fertilization, yield, persistence, timothy

A method is described for filling polygons according to the GKS Fill Area definition on terminals that provide only region‐filling capabilities. The advantages and disadvantages of using this algorithm in GKS device drivers are considered.

Hepatic involvement in listeriosis is uncommon in adults. Cases previously reported include three presenting as acute hepatitis and three of listerial liver abscesses found at necropsy. We report a case of multiple listerial liver abscesses. We believe this to be the first time this diagnosis has been made in a living patient.

Aspects of a prototype binding of GKS to the C++ programming language are presented. The binding makes use of classes and derived classes to define GKS concepts such as segments and workstations. Operator overloading is used for some GKS Functions.

A case of ampicillin and chloramphenicol resistant Haemophilus influenzae meningitis successfully treated with cefotaxime is described.

Forty-eight spring-born bulls (representing early-, medium- and late-maturing breed groups) and 30 fall-born bulls (representing medium- and late-maturing breed groups) were randomly assigned to either a control or treatment group within each breed group. Treated bull calves were initially implanted with Ralgro® at approximately 55 d of age and reimplanted every 84 d for a total of four implants. All bulls were weaned after 140 d on trial at an average age of 195 d, placed into a feedlot in pens of three or four within breed and treatment groups and gradually adjusted to a high grain ration. Bulls were slaughtered when they reached approximately 7 mm of backfat over the 12/13th ribs, determined ultrasonically. Weaning weights and daily gain to weaning were increased slightly, but not significantly, by implanting in both calving groups. Effects tended to be more pronounced with the earlier (medium) maturing breed groups. No effect of implanting on feedlot performance was observed in either the spring- or fall-born bulls. A reduction in the morbidity rate of the spring-born implanted bulls tended to occur during a period of disease outbreak shortly after weaning. Testicular weights were reduced (P < 0.05) with the use of implants in both calving groups. Scrotal circumference was decreased (P < 0.05) by implanting in the spring-born bulls only. For both of these traits, effects were also more pronounced in the early- and medium-maturing breed groups. Effects of implanting on carcass characteristics were slight. Key words: Ralgro®, bulls, live performance, carcass characteristics, testicular development

Characters useful for the identification of ammocoetes of lampreys found in British Columbia were verified by rearing ammocoetes through metamorphosis to specifically identifiable adults. We developed a key that employs new as well as some previously published features. We showed that published descriptions previously thought to be characteristic of species are unreliable for taxonomy. Counts of trunk myomeres and body proportions were not useful for separating species.Key words: ammocoetes, taxonomy, identification criteria

The amoebicidal and amoebistatic action in vitro of 24 compounds was tested on two strains of Acanthamoeba, A. polyphaga and A. castellanii, isolated from eye infections in this country. For comparison, the Ryan strain of A. castellanii and Naegleria gruberi L-1 were also examined. Nine compounds showed sufficient activity to merit further consideration, ie, acriflavine, proflavine, hydroxystilbamidine isethionate, paromomycin, miconazole, amphoterin, neomycin, polymyxin, and the last two combined in Neosporin.