Showing papers by "University of Guelph published in 1976"

Triplet states via intermediate neglect of differential overlap: Benzene, pyridine and the diazines

Abstract: The intermediate neglect of differential overlap technique is modified and applied to the calculation of excited triplet states. The resulting method generally reproduces the transition energies of the better-classified observations within a rms error of 1000 cm−1. Trends are well reproduced, and the calculated orders ofn-π* and π-π* triplet states are in good accord with the experimental information to date. The method is applied to benzene and the azines. The lowest four triplet states of benzene are calculated in good accord with experiment. Pyridine is calculated to have an-π* triplet nearly degenerate with the lowest lying π-π* triplet, corroborating suggestions of Japar and Ramsay based on experimental information. A detailed analysis is made of the diazines, and assignments are suggested for the higher lying triplet states not yet classified or not yet observed.

A Possible Essential Role for Dietary Linolenic Acid in the Development of the Young Rat

Abstract: Female rats were fed semi-purified diets containing 10% safflower oil or 10% soybean oil for six weeks prior to mating and through-out pregnancy and lactation. The progeny were weaned to the diet of the dam. Physical, neuromotor and reflex development was monitored in the progeny prior to weaning and learning ability of the mature progeny was assessed in a simple Y-maze test. Brain lipid analyses were conducted in the progeny at birth, 21 and 210 days of age. Inclusion of soybean oil in the diet resulted in higher levels of 22:6omega3 and lower levels of 22:5omega6 in the brain ethanolamine glycerophosphatides. The nature of the dietary fat exerted no effect on the physical development, onset of reflexologic responses or onset of neuromotor co-ordination in the pups. The soybean oil-fed animals spent more time in certain neuromotor activities possibly associated with explorative drive than did their safflower oil-fed counterparts. The performance of the mature soybean oil-fed progeny in the discrimination-learning test was superior to that of progeny fed safflower oil. The association of superior learning capacity with dietary soybean oil-induced incorporation of omega3 fatty acids into the brain glycerophosphatides is offered as support for an essential role for dietary linolenic acid for the young rat.

Ovarian function and estrus in dairy cows during early lactation.

Abstract: The onset of ovarian function and occurrence of estms were monitored in two groups of Holstein cows over the first 90 days postpartum. Group 1 consisted of 36 animals housed in a free stall area and observed continuously for estrus with closed circuit television and a time lapse videorecorder. Group 2 consisted of 33 cows housed in tie stalls with estrus detected by the herdsmen. Blood samples were collected twice weekly and assayed for progesterone. The plasma progesterone profiles were used to monitor ovarian function and determine ovulation time. In both groups there was close agreement between basal progesterone concentrations and observed estrous activity. There was no difference between the groups in the incidence of abnormal ovarian activity, or in the interval from parturition to first, second or third ovulation. For all cows with normal ovarian function, the median time to first ovulation was 19.5 days and the time to the second and third ovulation was 44.4 + 13.2 and 63.7 + 10.1 days, respectively. A significant difference was observed between the two groups in the days from parturition to first detected estrus: Group 1, 34.5 + 12.8; Group 2, 56.6 -+ 26.5, (P>.01) and in the percentage of cows in which estrus was detected at the first, second and third ovulation: Group 1, 50%, 94% and 100%; Group 2, 20%, 44% and 64%, (P<.01). (

Influence of level and type of dietary protein, and of level of feeding on feed utilization by rainbow trout.

Abstract: In the first experiment, diets with 40%, 50% and 60% protein containing herring and soybean meals, and diets with 50% and 60% protein containing herring and soybean protein concentrates were fed at 100%, 85% and 70% of the ad libitum intake. Both increasing the protein level and using the concentrated protein sources resulted in lower gains, and in increases in the amounts of digestible protein and energy consumed for the deposition of protein and energy in the fish carcasses. This difference between the herring and soybean meals, and protein concentrates was not due to differences between their digestibilities. Restriction of feed intake reduced gain, but within these lower levels of gain, the 50% and 60% protein diets have higher final body weights than the 40% protein diet. Restriction of feed intake resulted in carcasses with higher protein and lower fat contents. In the second experiment, two series of diets containing either 40%, 35%, 30% or 25% protein from both herring and soybean meals, or 35%, 30% and 25% protein from herring meal were fed. Reducing the protein level below 40% resulted in lower final body weights, higher feed: gain ratios and carcasses with more protein and less fat. Comparisons of the isonitrogenous pairs of diets showed no differences in final body weights, feed: gain ratios and carcass composition. Reducing the protein level in the diet reduced the amount of protein consumed per unit protein level in the diet reduced the amount of protein consumed per unit protein deposition, but increased the amount of gross energy per unit energy deposited in the carcass.

Clinical Evaluation of Blood Lactate Levels in Equine Colic

Abstract: Blood lactate levels were evaluated in 36 horses (43 cases) presented with colic. A correlation between increasing blood lactate levels and decreasing percentage survival has been shown. An appreciable anion gap was found in 7 of 10 cases analyzed in detail but in each case the entire gap could not be accounted for by lactate alone. Proposals are offered to account for the unmeasured anions. Blood lactate determination is suggested as a prognostic rather than a diagnostic aid for the equine practitioner and should be used to augment other clinical findings in the horse exhibiting colic.

Type C virus in lymphosarcoma in northern pike (Esox lucius)

Abstract: THE northern pike (Esox lucius) is a highly prized freshwater fish, both as a game fish and as a commerical species. Epizootics of lymphosarcoma occur widely in North American pike1 and in the Old World2,3. The tumour in pike has been found with an overall frequency of 20.9%, which is the highest frequency of a malignant neoplasm in any known free living vertebrate1. All pike with the tumour have cutaneous lesions, and epizootiological evidence suggests that the disease is transmitted horizontally by contact during spawning1. The tumour is transplantable and evidence of cell-free transmission has been found1,4. In an attempt to resolve the aetiology of the disease, we have investigated the presence of oncornavirus in pike lymphoma. Since all known RNA tumour viruses possess the enzyme reverse transcriptase, we have sought the activity of this enzyme in post-mitochondrial particulate fractions prepared from pike lymphoma tissue.

Prolonged practice of a simple motor task by preferred and nonpreffered hands.

Abstract: After prolonged practice (1300 10-sec trials) the tapping speed of the nonpreferred hand reached that of the preferred hand on a simple finger-tapping task. Analysis of the intertap intervals showe...

The Moral Point of View

Abstract: In his discussion of morals in the Third Book of the Treatise, Hume claims that the taking of what I shall call a general point of view is a necessary condition of the arousal of moral feelings. This aspect of Hume's theory has not received much attention from his commentators before now, although its implications for the theory as a whole might be regarded as significant.

Ecological fish production in a small Precambrian shield lake

Abstract: Ecological fish production of 30.8 kg ha−1 yr−1 was estimated for a 6.2 ha Precambrian shield lake by treating it with a piscicide and removing all fish. This is one of the lowest productions recorded for any waterbody.Perca flavescens contributed 71% to this total. The five other indigenous species werePimephales promelas, Semotilus margarita, S. atromaculatus, Notemigonus crysoleucas andSalvelinus fontinalis. Seventy-five percent of the production occurred in the first year of life. A conventional capture-mark-recapture experiment conducted onP. flavescens prior to the piscicide treatment underestimated the density by nine times and the total production by eight times. The gravest error occurred in the estimation of density for the younger age groups. Production studies can quantify the ecological success of a species, and provide a measure of stress in aquatic ecosystems.

Ixodes scapularis Say on white-tailed deer (Odocoileus virginianus) from Long Point, Ontario.

Abstract: Ixodes scapularis Say was the only species of tick found on white-tailed deer, Odocoileus virginianus, collected at Long Point, Ontario from October 1972 to August 1973. Adults were most abundant from September 1972 to April 1973. Larvae were found throughout the study period except during February. Nymphs were scarce during winter months but fairly common during spring and summer. Most adults were found on the neck and shoulders. Larvae occurred mainly on lower regions of the body and nymphs mainly on the head, shoulders, forelegs and brisket.

Effect of photoperiod on development and number of spikelets of a temperate and some low‐latitude wheats

Abstract: SUMMARY Four low-latitude cultivars (two Mexican and two Rhodesian) and a Canadian cultivar were grown in controlled environments in four photo-periods, 16, 13, 10 and 7 h, respectively. Plants of two of the low-latitude cultivars were also transferred between long and short photoperiods during ear differentiation. The intervals from sowing to successive stages of ear development up to the formation of the terminal spikelet, and to ear emergence, and the number of leaves, all increased as photoperiod decreased. The Canadian cultivar responded most and one of the Rhodesian cultivars least to changes of photoperiod in these respects. However, with all the low-latitude cultivars, the interval between formation of the terminal spikelet and emergence of the ear responded similarly and relatively little to decreasing photoperiod except when photoperiod was reduced from 10 to 7 h. The mean rate of spikelet production decreased as the duration of the period of spikelet production (DSP) increased, i.e. as ear development slowed down with decrease in photoperiod. Accordingly number of spikelets per ear increased curvilinearly as DSP increased, suggesting a maximal number of spikelets of about thirty. Rate of spikelet production apparently differed between cultivars. Development of the ear slowed down when plants were moved to a shorter photoperiod and accelerated when they were moved to a longer photoperiod, both at the time at which the shoot apex began to elongate and at the double ridge stage. Final number of spikelets per ear increased when ear development was slowed down and decreased when it was accelerated.

Effect of Salinity on the Photosynthesis of the Halophyte Salicornia rubra and Distichlis stricta

Abstract: The photosynthesis and biomass production of two contrasting species, Salicornia rubra and Distichlis stricta from the same habitat, were studied under different light intensities and osmotic conditions. Application of NaCl increased the biomass and succulence of Salicornia and decreased that of Distichlis. Ethylene glycol, EG mol. wt. 62.07, and 1:1 NaCl-EG killed Salicornia and affected Distichlis adversely. The CO2 uptake of both the species increased with increasing light intensity and was strongly influenced by the application of NaCl. All concentrations of NaCl stimulated the CO2 uptake of Salicornia, but decreased that of Distichlis. NaCl significantly decreased the light compensation point of Salicornia but had no effect on that of Distichlis. The CO2 efflux of the two species at 4.52 klx was not significantly different. The rate of CO2 uptake of both the species declined with time at all levels of treatment. Salicornia had a more rapid decline in CO2 uptake in absence of NaCl, whereas that of Distichlis was relatively unaffected by it. Although the tissue Na concentration of the two species increased with increasing NaCl concentration in the medium, the increase in Salicornia was 3.0 to 5.5 times greater than that of Distichlis. Increasing NaCl concentration decreased the chlorophyll concentration of Salicornia and increased that of Distichlis. This resulted in higher ratios of photosynthesis/chlorophyll concentration in Salicornia as against lower ratios in Distichlis. The tissue OP (osmotic potential) of both the species decreased with decreasing OP of the medium. In Salicornia the tissue OP decrease was concurrent with an increase in the CO2 uptake, whereas the CO2 uptake of Distichlis declined with decreasing OP of the medium despite a decrease in its tissue OP. It is concluded that Salicornia requires NaCl for its normal development, whereas Distichlis is adversely affected by it. Both species however, are better adapted to osmotic stress due to natural osmotic agents like NaCl, than to the osmotic stress due to artificial osmotic agents like ethylene glycol.

Preliminary observations on nitrogen transport during summer in a small spring-fed Ontario stream

Abstract: Nitrogen transport in a 2 km-long, spring-fed stream was studied during the summer months by analyzing weekly water samples from four stations. The water at the spring had a consistently high level of nitrate-N ranging from about 7 mg/l in late spring to about 3 mg/l in early fall. However, over the length of the stream, 60% (about 97 kg) of the incoming nitrate-N is lost from the water during the summer period. The loss, which does not appear to be attributable to the uptake by aquatic macrophytes or to immobilization, is thought to result from denitrification.

Specific formation of arachidonoyl phosphatidylinositol from 1-acyl-sn-glycero-3-phosphorylinositol in rat liver.

Abstract: The conversion of 1-acyl-sn-glycero-3-phosphorylinositol-3H into phosphatidylinositol-3H was studied using rat liver microsomal and homogenate preparations. The nature of the molecular species of phosphatidyl inositol so formed in the absence of added acyl moieties was determined after fractionating the radioactive product by means of argentation thin layer chromatography. In other experiments, the possible specificity of the microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphorylinositol acyltransferase towards different acyl-CoA derivatives was investigated. Maximum conversion of 1-acyl GPI to the diacyl analogue was dependent on the addition of adenosine triphosphate and CoA when exogensou acyl groups were omitted from the incubation medium. Under these latter conditions, the tetraenoic species comprised 56-74% of the total molecular species of newly-formed phosphatidylinositol. The microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphorylinositol acyltransferase showed a marked preference for arachidonoyl-CoA. The present results suggest that the enrichment of rat liver phosphatidyl inositol in arachidonic acid may arise when 1-acyl-sn-glycero-3-phosphorylinositol is acylated to form phosphatidylinositol.

Lethal interaction of ubiquitous insecticide carriers with virus

Abstract: Large quantities of presumably nontoxic petroleum oil by-products are introduced into the environment as pesticide dispersal agents and emulsifiers. An increase in viral lethality with a concomitant influence on the liver and central nervous system occurs in young mice previously primed with such chemicals.

The metabolism of higher chlorinated benzene isomers.

Abstract: The metabolism of the isomeric tri- and tetrachlorobenzene isomers, penta- and hexachlorobenzene was investigated in the rabbit. The major urinary metabolites of the isomeric tri- and tetrachlorobenzenes were identified as the corresponding tri- and tetrachlorophenols whose structures were confirmed by chromatographic analyses. The genesis of the formation of metabolites is discussed in terms of their possible arene oxide intermediates in which the NIH shift of a chlorine atom is observed in the oxidation of many of the isomers. Pentachlorobenzene is metabolized to give both pentachlorophenol and a dechlorination–hydroxylation product which was identified as 2,3,4,5-tetrachlorophenol. The hexachlorobenzene substrate did not give any phenolic metabolites.

Entry of pesticides into the plant symplast as measured by their loss from an ambient solution

Abstract: A method was developed to determine the extent of penetration of substances into the plant symplast The known apoplastic dye trisodium 3-hydroxy-5,8,10-pyrenetri-sulphonate (PTS) and various systemic pesticides were studied using potato tuber tissue The dye penetrated only 5% of the volume of living tissue while those pesticides which display an apoplastic pattern of transport in plants penetrated the entire tissue volume The pesticides diffused freely out of the tissue when it was transferred to fresh medium It is proposed that the term euapoplastic be used to describe chemicals that behave like the dye, and that the term pseudoapoplastic be used to describe chemicals that behave like atrazine, carbendazim, carboxin and diuron 2,4-D, which displays a symplastic transport pattern in the plant, was concentrated by the tissue and did not diffuse out freely It appears that the property which allows a pesticide to be transported in the symplast is not its ability to penetrate the plasmalemma but rather its ability to be retained by the symplast after entry