Showing papers by "University of Guelph published in 1978"
TL;DR: In this article, the spectrum and mixing angles of negative-parity baryons in a quark-model framework inspired by quantum chromodynamics were discussed, and good agreement with experiment in the $S = 0$ and $S=\ensuremath{-}1$ sectors were obtained.
Abstract: We discuss the spectrum and mixing angles of negative-parity baryons in a quark-model framework inspired by quantum chromodynamics. We take into account in zero order the removal of the degeneracy between the two $P$-wave states of the three-quark system in the $S=\ensuremath{-}1$ sector, as well as the hyperfine interaction between quarks, but neglect spin-orbit coupling. We find good agreement with experiment in the $S=0$ and $S=\ensuremath{-}1$ sectors where there are data and predict the $S=\ensuremath{-}2, \ensuremath{-}3$ sectors.
722 citations
TL;DR: A review of the experimental techniques for the measurement of lipid oxidation can be found in this article, where a spectrum of tests ranges from simple organoleptic evaluations to chemical and physical methods, and the ultimate criterion for the suitability of any test is its agreement with sensory perception of rancid flavors and odors.
Abstract: Lipids become rancid as a result of oxidation, and this oxidative rancidity is a major cause of food deterioration. The acceptability of a food product depends on the extent to which this deterioration has occurred. Thus some criterion for assessing the extent of oxidation is required. This paper reviews the experimental techniques for the measurement of lipid oxidation. The spectrum of tests ranges from simple organoleptic evaluations to chemical and physical methods. There is no ideal chemical method which correlates well with changes in organoleptic properties of oxidized lipids throughout the entire course of autoxidation. The methods discussed each give information about particular stages of the autoxidative process, and some are more applicable to certain lipid systems than others. The method of choice depends on a number of factors including the nature and history of the oxidized sample, the type of information required, the time available, and the test conditions. Clearly, there is a need for a more thorough assessment of the available methods so that unreliable, cumbersome methods may be discarded and modifications made to the remaining methods to maximize the information obtained. The ultimate criterion for the suitability of any test is its agreement with sensory perception of rancid flavors and odors.
692 citations
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TL;DR: Follow-up studies of autistic children have two general aims: (a) to describe what such individuals are like in later life (i.e., the course and outcome of the autistic condition), and (b) to identify factors which are associated with differences in course and outcomes.
Abstract: Follow-up studies of autistic children have two general aims: (a) to describe what such individuals are like in later life (i.e., the course and outcome of the autistic condition), and (b) to identify factors which are associated with differences in course and outcome. An important secondary consequence of such investigations is the contribution they may make to classification. Since definitions of autism vary somewhat and the numbers of afflicted children are few, comparability among studies is at the same time both uncertain and especially necessary. This is particularly the case as a wide variety of terms have been applied to psychoses beginning in infancy or early childhood. Thus, in some centers the terms “childhood schizophrenia,” “child psychosis,” or “atypical child” have been used for disorders fulfilling the usually, accepted diagnostic criteria “autism.” On the other hand, these same terms have also been used for conditions which clearly are not autistic. Accordingly, an initial survey was made of all follow-up studies which referred to autistic, schizophrenic, or psychotic disorders beginning in early childhood in order to determine which could be taken to refer to autistic children.
377 citations
TL;DR: In this paper, a survey was made of the malonaldehyde content of 96 fresh and processed meat and fish samples obtained from supermarkets. And they found that cooking led to only slight increases in MA in most samples, but up to 10-fold increases in roasts cooked for 3 hours.
Abstract: A survey was made of the malonaldehyde (MA) content of 96 fresh and processed meat and fish samples obtained from supermarkets. MA content ranged from 0.14 μg/g in a cooked ham sample to 10.05 μg/g in a cooked chicken sample. Ninety-two percent of the processed or cured meats and 38% of the fresh meats contained less than 1 μg/g. Sixty percent of the fresh meat samples ranged between 1 μg/g and 6 μg/g. Cooking led to only slight increases in MA in most meat samples, but up to 10-fold increases in roasts cooked for 3 hr.
317 citations
TL;DR: In this article, the Borel-Leroy, Pade-approximant method for the n-component φ^4 model was used to estimate the critical exponents for the coefficients of the Callan-Symanzik equation in three dimensions.
Abstract: Recent results giving both the asymptotic behavior and the explicit values of the leading-order perturbation-expansion terms in fixed dimension for the coefficients of the Callan-Symanzik equation are analyzed by the the Borel-Leroy, Pade-approximant method for the n-component φ^4 model. Estimates of the critical exponents for these models are obtained for n=0, 1, 2, and 3 in three dimensions with a typical accuracy of a few one thousandths. In two dimensions less accurate results are obtained.
301 citations
TL;DR: Gottlieb et al. as mentioned in this paper presented a classification scheme composed of 26 helping behaviours which were empirically generated and reliably coded by a team of three judges, based on a content analysis of interview protocols.
Abstract: A classification scheme is presented composed of 26 helping behaviours which were empirically generated and reliably coded by a team of three judges, based on a content analysis of interview protocols. The protocols describe the types of informal social support provided to a sample of single mothers. The categories are organized into four main classes of influence and each category has been defined and illustrated with an example taken from the protocols. In order to illustrate one application of the scheme, data are presented contrasting the helping behaviours extended to the women in response to three problem areas. Methods of further validating the scheme and evaluating the efficacy of informal social support are discussed. One of the hallmarks of the community mental health ideology is that coping resources should be available to people experiencing stress at an early time and in their natural environment. Translated into practice, this ideology has taken the form of mental health consultation with a variety of "community caregivers" such as teachers, clergymen, and family physicians who have broad contact with the public and who have been trained to engage in basic diagnostic, counselling, and behaviour change activities with the "clients" they normally serve. Recently, however, this approach to the secondary prevention of mental disorder has been criticized both on the basis of insufficient empirical evidence of preventive outcomes (Mannino & Shore, 1975) and on grounds of professional colonialism towards the caregiver-consultees (Gottlieb, 1974). The latter criticism - that training in the professional mould may supplant or weaken the natural helping skills of caregivers - has been strengthened with the appearance of a literature documenting the existence of numerous natural forms of service delivery which operate largely outside the professional sphere of influence, but which involve a great many people (Collins & Pancoast, 1976; Gottlieb, 1976). These natural support systems range from the more organized self-help group to the spontaneous helping transactions extended within personal networks. A number of these natural human services are currently being subjected to evaluative research; however, the more general claim This research was supported by Grant No. S74-0726 from the Canada Council. Thanks are expressed to John Hughes, Barbara Piggins, Bill Psihogios, and Michael Wuitchik for their patience and attention to the minutiae associated with the development of the classification scheme. Requests for reprints should be addressed to Benjamin H. Gottlieb, Department of Psychology, University ofGuelph, Guelph, Ontario, NIG 2W1.
238 citations
TL;DR: The 96 h median lethal concentration (LC50) of total dissolved copper varied from 20 μg 1−1 in soft acid water to 520 μg l− 1 in hard alkaline water, in tests with hardness ranging from 30 to 360 mg l−1 as CaCO3 and pH from 5 to 9 as mentioned in this paper.
220 citations
TL;DR: In this article, critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness Measurements were made after exposure for 05, 5, 10, and 30 days when copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance.
160 citations
TL;DR: Intraperitoneal injection or subcutaneous implantation of melatonin in beeswax resulted in a vast increase in melatonin content in the retina and the Harderian gland of the juvenile and adult rats.
152 citations
TL;DR: A computer-simulated ESR spectrum for the trichloromethyl adduct of phenyl-t-butyl nitrone can reproduce the essential features of the spectrum of the spin-trapped radical produced enzymically from CCl4.
145 citations
TL;DR: The basic theory and various modifications of the selection index are reviewed and changes of parameters due to selection and sampling errors of parameter estimation are discussed.
Abstract: This paper reviews the basic theory and summarizes various modifications of the selection index. The limitations of selection index are discussed in four parts: (1) changes of parameters due to selection. (2) sampling errors of parameter estimation. (3) evaluation of relative economic weights and (4) internal deterrents to index selection.
TL;DR: Postparturition effects of unfamiliar males in the collared lemming (Dicrostonyx groenlandicus) are reported and the significance of these effects on reproductive strategies in this species is discussed.
Abstract: COMPETITION among males for females may continue after mating1. For example, postfertilisation competition among males occurs in many primates2. In rodents, unfamiliar (or strange) males can block pregnancy (Bruce effect) either before3–9 or after7,9 implantation. Here, we report on postparturition effects of unfamiliar males in the collared lemming (Dicrostonyx groenlandicus) and discuss the significance of these effects on reproductive strategies in this species.
TL;DR: In this paper, the texture of raw and soaked cowpeas (Vigna unguicuiata) was measured using a wedge-type blade mounted in an Instron testing machine to cut across the cotyledons.
Abstract: A method has been developed to measure the texture of raw and soaked cowpeas (Vigna unguicuiata) using a wedge-type blade mounted in an Instron testing machine to cut across the cotyledons. It was found that soaking raw cowpeas in water prior to cooking produced a softer bean and the decrease in hardness was proportional to the soaking time. Texture of cooked beans could be predicted from the texture of the corresponding soaked bean. The influence of cooking temperature and time on bean texture was studied using the shear-compression cell of - the Texture Test System and the Ottawa Texture Measuring System cell with a wire extrusion grid. It was found that the rate of cooking relative to texture followed first order kinetics. Scanning electron microscopy was used to study changes in microstructure during the cooking process. The major effect observed was a breakdown of the middle lamella; cell walls remained intact.
TL;DR: In this article, it was shown that the SU(6)-violating effects can be understood quantitatively in terms of the admixtures of excited-state configurations in the nucleon expected on the basis of color hyperfine interactions.
Abstract: The decay amplitudes for ${D}_{15}\ensuremath{\rightarrow}p\ensuremath{\gamma}$, the amplitude for ${D}_{05}\ensuremath{\rightarrow}\overline{K}N$, and the charge radius of the neutron are zero in the SU(6) limit, but are observed to be nonzero. We show that all of these SU(6)-violating effects can be understood quantitatively in terms of the admixtures of excited-state configurations in the nucleon expected on the basis of color hyperfine interactions. In particular, the admixture of $^{2}S_{M}$ (i.e., [70, ${0}^{+}$]) with an amplitude of about - \textonequarter{} is central to understanding all three effects.
TL;DR: Individual production parameters of a population of Single Comb White Leghorn hens were recorded for 48 weeks and six efficient and six inefficient birds were selected on the basis of feed efficiency.
TL;DR: In this article, a new symmetry breaking mechanism for low mass negative parity hyperons was proposed, where a pair of orbital states which are degenerate when all three quarks have the same mass splits up when the quarks had different masses.
TL;DR: In this paper, the method of Backlund transformations was employed to derive in 2 + 1 and 3 + 1 dimensions exact solutions of the sine-Gordon equation, which allowed us to generate without additional quadratures an infinite class of new time-dependent solutions.
Abstract: The method of B\"acklund transformations is employed to derive in 2 + 1 and 3 + 1 dimensions exact solutions of the sine-Gordon equation $[{\ensuremath{
abla}}^{2}\ensuremath{-}{c}^{\ensuremath{-}2}(\frac{{\ensuremath{\partial}}^{2}}{\ensuremath{\partial}{t}^{2}})]\ensuremath{\chi}=sin\ensuremath{\chi}$. A formula is developed in 3 + 1 dimensions which permits us to generate without additional quadratures an infinite class of new time-dependent solutions.
TL;DR: Histological evaluation of heart, liver, and kidney tissue sections indicated extensive cellular damage, and isolated fractions from heated fat samples, which contained concentrations of cyclic monomer and dimer derivatives, were used in animal studies.
Abstract: In deep-fat frying the fat is used over and over again, and moisture and air are mixed into the hot oil. Substantial quantities of the heated fat are absorbed into the fried foods. Many reports from experimental observations with animals fed these fats have shown biological effects ranging from a slight depression in growth, all the way to very poor growth, diminished feed efficiency, increased liver size, fatty necrosis of the liver, and various other organ lesions. Obviously, certain fat constituents may be changed by frying conditions, and the adverse biological effects are relative. We are at the stage in studying these heated fats where selected techniques including biochemical parameters, histopathological evaluations, and tissue culture in monolayers can be good indicators of some of the specific effects on biological tissues. Isolated fractions from heated fat samples, which contained concentrations of cyclic monomer and dimer derivatives, were used in animal studies. Incorporation of the above materials into rat diets produced distended flatulent stomachs and intestines, gastric ulcers, and multiple focal hemorrhages. Histological evaluation of heart, liver, and kidney tissue sections indicated extensive cellular damage. Livers and kidneys exhibited the most severe lesions. Neonatal heart cells established as monolayers on glass cover slips were exposed to fractions from heated or fresh fats. Cellular damage including pyknosis, vacuolization of the cytoplasm, and mitotic aberrations were observed. Uptake of14C-labeled fatty acid by the triglyceride fraction of the cells was increased with heated fats.
TL;DR: Plasma T4 levels in fish treated with thiourea were significantly lower than in comparable controls after 6, 9 and 15 days and plasma T3 levels were lower after 15 days treatment and T3/T4 ratios did not differ significantly at any time period.
Abstract: A single injection of ovine TSH (1.1 μg or 2.2 μg/g body weight) effected a significant (P<0.01) increase in plasma T4 levels in rainbow trout within 9 h and 1 h respectively. In fish given the higher dose the T4 levels were still significantly higher (P<0.01) than in the controls 24 h after the injection. Ovine TSH had no significant effect on plasma T3 levels. Plasma T3/T4 ratios in fish given the higher TSH dose were significantly lower than the controls at 3 h (P<0.01), 6 h (P=0.01), 9 h and 24 h (P<0.05) while in fish given the lower dose they were significantly lower than in controls at 3 h (P<0.01), 6 h (P=0.01) and 9 h (P<0.05). T4 levels in TSH-injected fish were significantly higher (P<0.05) than in controls after 3 and 11 injections but were not significantly different after 16 injections. Plasma T3 and T3/T4 ratios did not differ significantly in fish given multiple injections of either TSH or saline. Plasma T4 levels in fish treated with thiourea were significantly lower (Po0.01) than in comparable controls after 6, 9 and 15 days and plasma T3 levels were lower (P<0.05) after 15 days treatment. T3/T4 ratios did not differ significantly at any time period. A single injection of bovine STH (10 μg/g body weight) effect a significant rise in plasma T4 levels 9 h (P=0.05) and 24 h (P<0.01) after the injection while ovine prolactin in a similar dose was without effect. Plasma T3 levels in saline injected fish showed a steady decline over the 24 h following the injection whereas levels in prolactin and STH injected animals tended to rise. T3 levels in the saline-injected fish were significantly higher (P<0.01) than in prolactin and STH injected animals 1 h after the injection but were significantly lower (P<0.01) than in the hormone-treated fish 24 h after the injection. There were no significant differences in T3/T4 ratios in any of the groups. Multiple injections of STH effected a significant increase (P<0.05) in plasma T4 compared with the controls; prolactin had no significant effect. There was no significant differences in plasma T3 concentration or T3/T4 ratios in any of the groups.
TL;DR: In this paper, anaerobic flasks with two different soils contained microorganisms which effectively reduced NO3− to N2 in the absence of C2H2 and in the presence or absence of CO2.
Abstract: Anaerobic flasks with two different soils contained microorganisms which effectively reduced NO3− to N2 in the absence of C2H2 and in the presence or absence of CO2. In the presence of C2H2, the microorganisms reduced NO3− to N2O and the further reduction of N2O to N2 was temporarily inhibited. This was shown for two partial pressures of C2H2 (0.1 kPa and 1.0 kPa). However. after a maximum of 168 h, microorganisms were able to reduce N2O to N2 in the presence of C2H2. This was shown in the presence of CO2 for both partial pressures of C2H2 and in the absence of CO2 for 1.0 kPa C2H2. The absence of CO2 delayed the complete reduction of N2O. Microorganisms which had reduced N2O in the presence of C2H2 retained this ability for at least 3 days after the original atmosphere containing C2H2 had been removed.
TL;DR: Monte Carlo experiments have been used to test the robustness of distribution-free confidence limits for the parameters of the Michaelis-Menten equation and when used in conjunction with the modified form of the direct linear plot they prove to be more robust than least-squares confidence limits.
TL;DR: There was a significant change in the incidence of left-handers with an inverted writing position over the six elementary school grades sampled with a much higher incidence in grades five and six than in the lower grades.
TL;DR: Regression analysis indicated that only Cu2+ and CuOH+ could be significantly correlated with growth rate and no distinction could be made among total soluble or extractable copper but predicted concentrations of six specific cupric ions varied with pH and hardness.
Abstract: Rainbow trout (Salmo gairdneri) were held at a ked ration and activity regime and were exposed to a number of copper, pH and hardness combinations. Growth rate, appetite and gross conversion efficiency were determined over three consecutive 10-day periods of exposure. Growth rate was most affected during the first 10 days of exposure and partial or complete recovery was observed thereafter. For a given pH, less copper was required to reduce growth by a given amount at low than at high levels of hardness. At a given hardness, copper-induced depressions in growth rate were more pronounced and recovery slower in a low than in a high pH. No distinction could be made among total soluble or extractable copper but predicted concentrations of six specific cupric ions varied with pH and hardness. Regression analysis indicated that only Cu2+ and CuOH+ could be significantly correlated with growth rate.
TL;DR: The results raise the question as to whether or not meaningful extremes within a population could provide the basis for a selection program aimed at reducing abominal fat pad size.
TL;DR: The Mediterranean monk seal population is estimated to be between 500 and 1000 with the population still declining as discussed by the authors, with the majority of the population concentrated in the eastern Aegean sea.
TL;DR: This finding is consistent with the view that there may be a cluster of testis-determining H-Y genes on the Y chromosome, and that translocation of a subcritical portion of these genes may generate a recessive mode of sex determination.
TL;DR: Aroclor 1248 induced microsomes mediated binding of 4-chlorobiphenyl to endogenous and exogenous nucleic acids, indicating a possible mechanism for the previously reported mutagenic action of this chlorobipenyl.
Abstract: The in vitro metabolism, mechanism of metabolism, and macromolecular binding of a monochlorobiphenyl component of commercial polychlorinated biphenyls (PCB) have been investigated. 4-Chlorobiphenyl was metabolized by rat liver microsomes in the presence of NADPH to yield a major metabolite, 4'-chloro-4-biphenylol, and a number of minor metabolites. The metabolism of deuterium-labeled 4-chlorobiphenyl proceeded with the NIH shift of the isotope and no observed isotope effect thus indicating the intermediacy of an arene oxide. Noninduced rat liver microsomes mediated the covalent binding between the 4-chlorobiphenyl and 4'-chloro-4-biphenylol substrates and endogenous microsomal protein. Prior in vivo administration of a commericial PCB preparation, Aroclor 1248 (Monsanto Chemical Co., containing 48 percent by weight of chlorine), resulted in an induced microsomal preparation which significantly increased the substrate-protein binding. The effect of various inhibitors on protein binding was investigated. Aroclor 1248 induced microsomes mediated binding of 4-chlorobiphenyl to endogenous and exogenous nucleic acids, indicating a possible mechanism for the previously reported mutagenic action of this chlorobiphenyl. The spectral properties of Aroclor 1248 induced cytochrome P-450 were investigated and compared with the pentobarbital-induced cytochrome fraction.