Showing papers by "University of Ottawa published in 1988"
TL;DR: The results seem to indicate that RF impedance imaging can potentially be used as a diagnostic modality for the detection of human breast carcinoma by suggesting structural and cellular inhomogeneities of the tumor tissue.
Abstract: Relative permittivity of infiltrating breast carcinoma and the surrounding tissue was measured. The experiments were performed at frequencies from 20 kHz to 100 MHz at 37 degrees C using an automatic network analyzer and an end-of-the-line capacitive sensor. Cole-Cole dielectric parameters were calculated by curve fitting using a computer program. Three main categories of tissues were considered: the central part of the tumor, the tumor surrounding tissue, and the peripheral tissue. Within each category, the large spread of the dielectric data for different specimens suggests structural and cellular inhomogeneities of the tumor tissue. However, certain consistency has been found in the dielectric relaxation time and the coefficient of the distribution of the relaxation time within each category. The results seem to indicate that RF impedance imaging can potentially be used as a diagnostic modality for the detection of human breast carcinoma. >
789 citations
TL;DR: This study represents a major step in escaping the current phenomenological approach to competition in community ecology, and provides a general predictive tool for studying competition in natural communities.
Abstract: Decades of study of interspecific competition in community ecology has yielded an overwhelming body of special cases but few general principles1–3. This is largely because of the phenomenological, non-predictive approach used4. Further progress requires a predictive approach5 that will enable general principles to be deduced that apply beyond the species and conditions of a particular study or site. General principles are best sought using a comparative approach, that is, the systematic screening of a large number of species under standardized experimental conditions6,7 We used 44 wetland plant species to test whether competitive ability could be predicted from plant traits. Multiple linear regression showed that there was a strong relationship between plant traits and competitive ability (r2 = 0.74). Plant biomass explained 63% of the variation in competitive ability and plant height, canopy diameter, canopy area and leaf shape explained most of the residual variation. This study represents a major step in escaping the current phenomenological approach to competition in community ecology, and provides a general predictive tool for studying competition in natural communities.
686 citations
TL;DR: Based on interviews with Nobel laureates, Merton^ observes that eminent scientists get disproportionately great credit for their contributions to science, while relatively unknown scientists tend to get disproportionately little credit for comparable contributions.
Abstract: Based on interviews with Nobel laureates, Merton^ observes that eminent scientists get disproportionately great credit for their contributions to science, while relatively unknown scientists tend to get disproportionately little credit for comparable contributions. Merton also proposes and supports the related hypothesis that a scientific contribution will have a greater visibility in the community of scientists when it is introduced by a scientist of high rank than when it is introduced by one who has not yet made his mark. This raises interesting implications as to the beneficial effect of having an established scientist put his or her name on a paper to get better visibility for junior coworkers. One side effect of the acclamation and acceptance given to proven and great scientists is the fact that centers of demonstrated scientific excellence are allocated far larger resources for research than centers that have yet to make their mark.
508 citations
TL;DR: The Reasoning and Rehabilitation Project comprised an experimental test of the efficacy of an unorthodox intervention program in the rehabilitation of high-risk adult probationers The program was derived from a series of sequential studies of the principles of effective correctional programs as discussed by the authors.
Abstract: The Reasoning and Rehabilitation Project comprised an experimental test of the efficacy of an unorthodox intervention program in the rehabilitation of high-risk adult probationers The program was derivedfrom a series of sequential studies of the principles of effective correctional programs These studies indicated that many offenders evidence deficits in cognitive skills which are essential for pro-social adjustment and that training in these skills is an essential ingredient of effective correctional programs Compared to regular probation and life skills training, cognitive training provided by probation officers led to a major reduction in re-arrest rates and incarceration rates among adult high-risk probationers
340 citations
TL;DR: Findings indicate the potential vehicular role for human hands in the spread of rotaviral infections and study infectious virus transfer between animate and inanimate surfaces.
Abstract: We tested the survival of the Wa strain of human rotavirus on the hands of volunteers and also studied infectious virus transfer between animate and inanimate (stainless steel disks) surfaces. The virus was diluted in a 10% suspension of feces, and 10 microliters (1 X 10(3) to 4 X 10(4) PFU) was placed on each of the four fingerpads of the left hand. One milliliter of 20% tryptose phosphate broth in Earle balanced salt solution was used for virus elution from each fingerpad, and the hands were disinfected with 70% ethanol before they were washed with an antiseptic soap and water. At 20, 60, and 260 min after inoculation, approximately 57, 43, and 7%, respectively, of the input infectious virus could be recovered. For virus transfer, the inoculum (2 X 10(4) to 8 X 10(4) PFU) was allowed to dry, and the donor surface was kept in contact with the recipient surface for 10 s at a pressure of approximately 1 kg/cm2. At 20 and 60 min after virus inoculation, 16.1 and 1.8%, respectively, of the input infectious virus could be transferred from the contaminated hand to a clean disk; when a clean hand was pressed against a contaminated disk, virus transfer was 16.8 and 1.6%, respectively. Contact between a contaminated and a clean hand 20 and 60 min after virus inoculation resulted in the transfer of 6.6 and 2.8%, respectively, of the input infectious virus. These findings indicate the potential vehicular role for human hands in the spread of rotaviral infections. Images
250 citations
247 citations
TL;DR: Analysis of the response curves over time suggested two processes: an improvement in the concussed group and a slowing in the control group, suggesting a recovery process.
Abstract: Twenty-two adults with mild concussions were assessed 5 times during the first 3 months after injury The initial tests were performed within 72 hours of injury Each evaluation included a neurological examination and neuropsychological reaction time (RT) tests of simple and choice RT variations The concussed subjects were compared with control subjects matched for age, sex, and education The time of day of the testing was equated for the two groups None of the concussed subjects had a significant neurological deficit and none was hospitalized There was no significant difference in the number of errors by the two groups on the RT tests On the simple RT test, requiring a predetermined response to a specific signal, there was no significant difference between the groups, although the concussed group was approximately 28 ms slower on the average than the control group On the choice RT tests, however, which demand an increased amount of attention and information processing, the concussed subjects were significantly slower than the normal control group, especially during the 1st month after injury Even after 3 months, the concussed subjects had not yet attained the skill of the control group Analysis of the response curves over time suggested two processes: an improvement in the concussed group and a slowing in the control group Within the concussed group, there was no correlation of RT with the severity of the concussion Even mild concussions can cause significant attentional and information processing impairment in the absence of any apparent neurological problems Specific neuropsychological tests are necessary to reveal the deficit A significant impairment seems to last for several weeks(ABSTRACT TRUNCATED AT 250 WORDS)
243 citations
TL;DR: In this paper, two surface sulfate species were formed after oxidation of between 10 and about 250 μmol g−1, and although the extent of formation of each was dependent on the quantity oxidized, the total band area between 1400-1350 cm−1 was a linear function of the quantity of H2S or SO2 introduced into the infrared cell.
221 citations
TL;DR: It is reported here that the monoclonal antibody HNK-1 reacts with the neurons at a very early stage of their differentiation and is, therefore, an early marker of the neuronal lineage.
Abstract: We have previously shown that retinoic acid-treated cultures of the P19 line of embryonal carcinoma cells differentiate into neurons, glia, and fibroblast-like cells (Jones-Villeneuve et al, 1982) We report here that the monoclonal antibody HNK-1 reacts with the neurons at a very early stage of their differentiation and is, therefore, an early marker of the neuronal lineage Cells in differentiated P 19 cultures synthesized acetylcholine but not catecholamines, suggesting that at least some of the neurons are cholinergic The neurons also carry high- affinity uptake sites for GABA but not for serotonin In long-term cultures, neuronal processes differentiated into axons and dendrites, which formed synapses This biological system should prove valuable for examining the development and maturation of cholinergic neurons, since their differentiation occurs in cell culture
214 citations
TL;DR: The results indicate that the model of species richness proposed by Grime has predictive power at a coarse-grained level of organization, among vegetation types, but does not survive the transition to a finer-graining level of organizations, the within vegetation type level.
Abstract: One of the few important empirical generalizations regarding herbaceous plant systems has been the demonstration that species richness is related to standing crop with maximum richness occurring at moderate levels of standing crop. This relationship is normally demonstrated by comparing among vegetation types (i.e., vegetation with different dominants). We undertook this study to test whether the species richness-standing crop relationship was evident at a finer-grained level of organization, the within vegetation type level. Fifteen wetland sites were sampled in eastern Canada and species richness and standing crop determined in each of 224 0.25 m2 quadrats. Each site was relatively homogeneous in terms of the dominant species present and were therefore categorized as single vegetation types. However, as a group, the sites comprised a wide range of vegetation types. A second order polynomial regression indicated a significant bitonic relationship between species richness and standing crop at the among-vegetation types scale, that is, when all 15 sites were combined. At the within-vegetation type level, however, no significant relationships were observed (p>0.05). The results indicate that the model of species richness proposed by Grime has predictive power at a coarse-grained level of organization, among vegetation types, but does not survive the transition to a finer-grained level of organization, the within vegetation type level. Therefore, the higher level processes which structure species richness patterns among vegetation types are not the same processes which determine richness patterns within a vegetation type.
211 citations
TL;DR: The authors assesses the state-of-the-art on the subject of international market selection based on a comprehensive review and synthesis of the literature and provides an inventory, taxonomy and brief review of the normative quantitative models that have been proposed in the literature, and compares them to current business practices in selecting foreign markets.
Abstract: This article assesses the state‐of‐the‐art on the subject of international market selection based on a comprehensive review and synthesis of the literature. It provides an inventory, taxonomy and brief review of the normative quantitative models that have been proposed in the literature, and compares them to current business practices in selecting foreign markets. This comparison reveals a theory‐practice gap that is discussed in the context of the methodological and conceptual weaknesses of the models. Suggestions for future research are made.
TL;DR: The authors estimated the average reliability, stability, and validity of the Minnesota Multiphasic Personality Inventory (MMPI), Rorschach Inkblot Test, and Wechsler Adult Intelligence Scale (WAIS) from articles published in the Journal of Personality Assessment and Journal of Clinical Psychology betwee
Abstract: We estimated the average reliability, stability, and validity of the Minnesota Multiphasic Personality Inventory (MMPI), Rorschach Inkblot Test, and Wechsler Adult Intelligence Scale (WAIS) from articles published in the Journal of Personality Assessment and the Journal of Clinical Psychology betwee
TL;DR: In this article, the authors analyzed the process of change in the best sessions of Emotionally Focused Marital Therapy (EFT) and found that higher levels of experiencing and more autonomous and affiliative interactions characterized "best" sessions of couples who were successful in therapy.
Abstract: Although there are a growing number of outcome research studies in marital therapy, there is a complete absence of research on change processes, and how such processes relate to outcome. This study attempts to analyze the process of change in the “best” sessions of Emotionally Focused Marital Therapy (EFT) (Greenberg & Johnson, 1986). Client performance in therapy was rated on depth of experiencing and the quality of interpersonal interactions. The occurrence of particular change events arising from the theoretical principles of EFT was also noted. Results confirmed hypotheses that higher levels of experiencing and more autonomous and affiliative interactions characterized “best” sessions of couples who were successful in therapy. The implications for treatment are discussed.
TL;DR: A comparison of the in vivo unidirectional flux ratios with the flux ratios calculated according to the transepithelial electrochemical gradients revealed that calcium uptake from the water requires active transport of Ca2+.
Abstract: Experiments were performed to determine whether gill transepithelial calcium fluxes in the freshwater trout (Salmo gairdneri) are passive or require active transport and to characterize the mechanisms involved. A comparison of the in vivo unidirectional flux ratios with the flux ratios calculated according to the transepithelial electrochemical gradients revealed that calcium uptake from the water requires active transport of Ca2+. The inhibition of calcium uptake by external lanthanum, the specific deposition of lanthanum on the apical surface of chloride cells, and the favorable electrochemical gradient for calcium across the apical membrane suggest that the initial step in branchial calcium uptake is the passive entry of calcium into the cytosol of chloride cells through apical channels that are permeable to calcium. The study of gill basolateral plasma membrane vesicles demonstrated the existence of a high-affinity calmodulin-dependent calcium-transporting system [half-maximal Ca2+ concentration (K0.5) = 160 nM, Vmax = 1.86 nmol.min-1.mg protein-1]. This system actively transports calcium from the cytosol of chloride cells into the plasma against a sizeable electrochemical gradient, thereby completing the transepithelial uptake of calcium. Calcium efflux occurs passively through paracellular pathways between chloride cells and adjacent pavement cells or between neighboring pavement cells.
TL;DR: The diencephalic prepacemaker nucleus (PPn) of gymnotiform electric fish projects to the medullary pacemaker nucleus and modulates its regular firing frequency and elicited frequency modulations were similar to those observed during the jamming avoidance response and during courtship.
Abstract: The diencephalic prepacemaker nucleus (PPn) of gymnotiform electric fish projects to the medullary pacemaker nucleus and modulates its regular firing frequency. Each firing of the pacemaker, in turn, drives an electric organ discharge (EOD). Two types of PPn neurons were retrogradely labeled from the pacemaker with HRP in Eigenmannia and Apteronotus. In both species, smaller ovoidal cells were found in the dorsomedial part of the PPn (PPn-G), and larger multipolar cells were found in the ventrolateral part of the PPn (PPn-C). This morphological distinction between the two subnuclei in the PPn was paralleled by a functional dichotomy. Microiontophoresis of L-glutamate in the PPn-G of both species elicited slow and gradual accelerations of EOD frequency characterized by a time constant on the order of seconds. The elicited frequency modulations were similar to those observed during the jamming avoidance response and during courtship. Glutamate stimulation of the PPn-C, in contrast, produced fast and abrupt frequency modulations characterized by a time constant on the order of milliseconds. These abrupt modulations resembled "chirps" observed during courtship and aggression. Similar behavior was produced by intracellular current injection into a PPn-C neuron of Apteronotus, and intracellular labeling of this neuron with Lucifer Yellow revealed a multipolar PPn-C neuron similar to those retrogradely labeled with HRP.
TL;DR: A partially purified, membrane-bound Na+-K+-ATPase fraction, prepared from the outer medulla of porcine kidney, was incubated in the presence of0.1 mM FeCl3, 1 mM ADP, and 0.1-100 mM H2O2 for either 15 or 30 min at 37 degrees C and showed decreases in enzyme activity, turnover rate, and SH content without suppressing MDA formation.
Abstract: A partially purified, membrane-bound Na+-K+-ATPase fraction, prepared from the outer medulla of porcine kidney, was incubated in the presence of 0.1 mM FeCl3, 1 mM ADP, and 0.1-100 mM H2O2 for either 15 or 30 min at 37 degrees C. The activity of ouabain-sensitive Na+-K+-ATPase was reduced proportionally to the concentration of H2O2 and the duration of incubation. There were decreases in SH contents and turnover rates of the Na+-K+-ATPase preparation, while malondialdehyde (MDA) and conjugated dienes were generated from the membrane lipids in the course of the incubation. The concentrations of ethanolamine (E) plasmalogen and of arachidonic acid in the E glycerophospholipid molecules were reduced by the free radical reaction. Similarly, a reduction in Na+-K+-ATPase activity and the formation of MDA and conjugated dienes, together with a decrease in E glycerophospholipids, were observed when the membrane fraction was exposed to ultraviolet irradiation (254 nm) for 30 min at 4 degrees C. Administration of 10 mM dithiothreitol alleviated the reductions in enzyme activity, in turnover rate, and in SH content without suppressing MDA formation. Addition of 2 mM butylated hydroxytoluene to the incubation mixture prevented the lipid peroxidation without totally normalizing the enzyme activity in the H2O2 experiment, whereas this antioxidant restored the ATPase activity to normal in the ultraviolet experiment. Microsomal fractions, prepared from the outer medulla of canine kidney after 1 h of unilateral ischemia and 1 h of reperfusion, showed a decreased Na+-K+-ATPase activity, a reduced amount of SH groups, and an increased MDA.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The measurements of feeding efficiency provides the basis for early identification of children who cannot be adequately nourished without ancillary feeding by nasogastric tube or by enterostomy.
TL;DR: It is concluded that preoperative exercise testing is useful to predict cardiac complications after arterial reconstruction, and patients who are able to achieve more than 85% of their predicted maximum heart rate and a high maximal oxygen uptake represent a low-risk group.
TL;DR: Its low crosslinker-to-acrylamide ratio allows the effective and rapid transfer of proteins to nitrocellulose membrane, thus improving the usefulness of protein blotting and improving the resolving power of two-dimensional gel electrophoresis.
TL;DR: In this paper, it was shown that poly(4-vinylpyridine) is compatible with a copoly(styrene-4-hydroxystyrene) containing 50 mol% of 4-hydroxstyrene units over the entire range of blend composition.
TL;DR: In this article, the authors presented descriptive data of three tests (Trail Making Test, Brown-Peterson Auditory Short-Term Memory Test, Paced Auditory Serial-Addition Test) for three age groups (16-29, 30-49, 50-69 years).
Abstract: Descriptive data of three tests (Trail Making Test, Brown-Peterson Auditory Short- Term Memory Test, Paced Auditory Serial-Addition Test) are presented for three age groups (16-29, 30-49, 50-69 years). The use of Box Plots allows rapid visual analysis of response characteristics of the defined group on each task.
TL;DR: Patients with fractures of the tibial spine were reviewed 3 to 10 years after injury and it was found that an anatomical reduction did not prevent either laxity or some loss of full extension of the knee.
Abstract: Forty-five patients with fractures of the tibial spine were reviewed 3 to 10 years after injury in order to determine the degree of residual laxity of the cruciate or collateral ligaments. After fractures which had been partially or completely displaced, some anterior cruciate laxity was evident, even if patients were asymptomatic. It was also found that an anatomical reduction did not prevent either laxity or some loss of full extension of the knee.
TL;DR: The experience suggests that the OSCE may be a powerful tool in the evaluation of clinical competence in nursing and that it may also be an effective facilitator for learning to perform clinical skills in nursing.
Abstract: The measurement of clinical skills performance continues to pose a challenge for nurse educators. This paper will report on the use of the objective structured clinical examination (OSCE) to measure the psychomotor learning outcomes of a programme designed to assist students to learn to conduct a nursing neurological examination. The OSCE has a tradition in medicine, having been developed by Ronald Harden in Scotland and first reported in the British Medical Journal in 1975, The University of Ottawa has the longest North American experience with this type of evaluation procedure and there is an increasingly rich medical literature referring to the OSCE, Although the OSCE appears to be a promising method for evaluating competence in the performance of clinical skills, there are no studies in the nursing literature examining the use ofthe OSCE as a method for evaluating the performance of clinical skills by nurses. Our experience suggests that the OSCE may be a powerful tool in the evaluation of clinical competence in nursing and that it may also be an effective facilitator for learning to perform clinical skills in nursing.
TL;DR: Asymmetry in memory at the level of the thalamus was observed, following the left-verbal, right-nonverbal dichotomy, and the significance of cortical/subcortical relationship in explaining observed behavioral changes is emphasized.
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01 Jan 198801 Aug 1988-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: In vitro brain slice preparation of the electrosensory lateral line lobe of weakly electric fish revealed that most ELL neurons and synapses retained their normal appearance for at least 10 h in vitro, raising possibilities that intrinsic membrane properties together with local synaptic interactions may regulate pyramidal cell responsiveness.
Abstract: An in vitro brain slice preparation of the electrosensory lateral line lobe (ELL) of weakly electric fish was developed. The morphology of this slice was studied and revealed that most ELL neurons and synapses retained their normal appearance for at least 10 h in vitro. The electrophysiological characteristics of the main ELL output neurons, the pyramidal cells, were measured. Extracellular electrode recordings demonstrated that pyramidal cells are capable of spontaneous, rhythmic spike activity. Intracellular recordings showed that intrinsic oscillations in membrane potential underlie the bursting behavior. The majority of pyramidal cells respond to depolarizing current pulses with an initial lag in spike firing followed by a non-accommodating, higher frequency spike train.
TL;DR: The results demonstrate that the induction of vitellogenesis in the trout by estradiol involves changes in the steady-state levels of a number of different mRNA and rRNA sequences and resembles that seen in Xenopus and chicken.
TL;DR: In this paper, the authors present an analysis and comparative evaluation of different methods used for the numerical solution of heat conduction with phase change problems, both freezing (melting) water as well as solidifiying liquid metal problems are examined.
Abstract: The work presents an analysis and comparative evaluation of different methods used for the numerical solution of heat conduction with phase change problems. Both freezing (melting) water as well as solidifiying liquid metal problems are examined. Emphasis is placed on weak formulations as they tend to be simple to program and easily implemented in existing single-phase codes. A new method based on the apparent capacity technique is proposed. In this technique an ''effective capacity'' is computed, based on the integration of temperature profiles over the nodal volumes. This method shows significantly better performance when compared with other methods for the numerical analysis of solidifying metals.
TL;DR: The Archean was the principal period for gold mineralization as discussed by the authors, and these rocks compose ∼12% of the exposed crust but have produced more than half of the world9s gold.
Abstract: The Archean was the principal period for gold mineralization.These rocks compose ∼12% of the exposed crust but have produced more than half of the world9s gold. Most major lode deposits formed at 2.7 ±0.2 Ga. This corresponds to the principal time of crustal thickening and stabilization, an essential part of which was formation of granulite, the anhydrous, refractory base for the crust. Upward streaming of mantle CO 2 along shear zones in the lower crust is one means for dehydrating amphibolite to form granulite and is accompanied by removal of large ion lithophile (LIL) elements to higher crustal levels. Archean lode-gold deposits were formed along major shear zones at intermediate crustal depths. They are enclosed by zones of CO 2 metasomatism, many of them kilometres in extent; δ 13 C data indicate that the CO 2 is juvenile. Some major Archean deposits have been shown to have formed from relatively oxidized hydrothermal fluids. CO 2 streaming with LIL-element depletion could only have occurred under relatively oxidized conditions that permitted a free CO 2 vapor to exist in the lower crust. Such conditions would also have favored dissolution of gold and associated sulfide and their transfer to the mid-crust in a CO 2 -H 2 O fluid, the H 2 O coming from dehydration of amphibolite.