Showing papers by "University of Ottawa published in 1997"
TL;DR: In this paper, the double-layer capacitance of carbon powder electrodes has been used as a means of storing electrical energy in a supercapacitor or an ultracapacitor, where the pseudocapacitance arises when, for thermodynamic reasons, the charge q required for progression of an electrode process is a continuous function of potential, V ; then the derivative d q /d V corresponds to a capacitance but one of a Faradaic kind.
1,417 citations
TL;DR: In this article, the role of UCP in the regulation of body mass was determined by targeted inactivation of the gene encoding it, and it was found that UCP-deficient mice consume less oxygen after treatment with a β3-adrenergic-receptor agonist and are sensitive to cold, indicating that their thermo-regulation is defective.
Abstract: The mitochondrial uncoupling protein (UCP) in the mitochondrial inner membrane of mammalian brown adipose tissue generates heat by uncoupling oxidative phosphorylation1. This process protects against cold2 and regulates energy balance3. Manipulation of thermogenesis could be an effective strategy against obesity4–9. Here we determine the role of UCP in the regulation of body mass by targeted inactivation of the gene encoding it. We find that UCP-deficient mice consume less oxygen after treatment with a β3-adrenergic-receptor agonist and that they are sensitive to cold, indicating that their thermo-regulation is defective. However, this deficiency caused neither hyperphagia nor obesity in mice fed on either a standard or a high-fat diet. We propose that the loss of UCP may be compensated by UCP2, a newly discovered homologue of UCP; this gene is ubiquitously expressed and is induced in the brown fat of UCP-deficient mice.
1,309 citations
1,299 citations
TL;DR: Management of patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible and the need for serial ultrasound testing is reduced and the rate of false-negative or false-positive ultrasound studies is reduced.
1,125 citations
TL;DR: Although clinical prediction rules comply with some methodological criteria, for other criteria, better compliance is needed.
Abstract: Background. —Clinical prediction rules are decision-making tools for clinicians, containing variables from the history, physical examination, or simple diagnostic tests. Objective. —To review the quality of recently published clinical prediction rules and to suggest methodological standards for their development and evaluation. Data Sources. —Four general medical journals were manually searched for clinical prediction rules published from 1991 through 1994. Study Selection. —Four hundred sixty potentially eligible reports were identified, of which 30 were clinical prediction rules eligible for study. Most methodological standards could only be evaluated in 29 studies. Data Abstraction. —Two investigators independently evaluated the quality of each report using a standard data sheet. Disagreements were resolved by consensus. Data Synthesis. —The mathematical technique was used to develop the rule, and the results of the rule were described in 100% (29/29) of the reports. All the rules but 1 (97% [28/29]) were felt to be clinically sensible. The outcomes and predictive variables were clearly defined in 83% (24/29) and 59% (17/29) of the reports, respectively. Blind assessment of outcomes and predictive variables occurred in 41% (12/29) and 79% (23/29) of the reports, respectively, and the rules were prospectively validated in 79% (11/14). Reproducibility of predictive variables was assessed in only 3% (1/29) of the reports, and the effect of the rule on clinical use was prospectively measured in only 3% (1/30). Forty-one percent (12/29) of the rules were felt to be easy to use. Conclusions. —Although clinical prediction rules comply with some methodological criteria, for other criteria, better compliance is needed.
1,115 citations
TL;DR: A comprehensive estimate of the prevalence of "cognitive impairment, no dementia" (CIND) in an elderly population of elderly Canadians and this diagnostic category includes a costly group of disorders that merit further study.
950 citations
Journal Article•
TL;DR: A consensus was reached by at least 90% of participants that the following 4 domains should be evaluated in future phase III trials of knee, hip, and hand OA: pain, physical function, patient global assessment, and, for studies of one year or longer, joint imaging.
Abstract: Significant progress has been made in outcome measurement procedures for osteoarthritis (OA) clinical trials, and guidelines have been established by the US Food and Drug Administration, European League Against Rheumatism, the World Health Organization/International League of Associations for Rheumatology, and the Group for the Respect of Ethics and Excellence in Science. However, there remains a need for further international harmonization of measurement procedures used to establish beneficial effects in Phase III clinical trials. A key objective of the OMERACT III conference was to establish a core set of outcome measures for future phase III clinical trials. During the conference, using a combination of discussion and polling procedures, a consensus was reached by at least 90% of participants that the following 4 domains should be evaluated in future phase III trials of knee, hip, and hand OA: pain, physical function, patient global assessment, and, for studies of one year or longer, joint imaging (using standardized methods for taking and rating radiographs, or any demonstrably superior imaging technique). These evidence based preferences, achieved with a high degree of consensus, establish an international standard for future phase III trials and will also facilitate metaanalysis and Cochrane Collaborative Project goals.
713 citations
TL;DR: This paper examined perceived competence in an L2 as a function of actual competence and language anxiety and found that L2 language anxiety, perceived L2 competence, and actual L 2 competence intercorrelated.
Abstract: Previous studies have shown a strong link between participants' apprehension about communicating and their perception of communicative competence in both native (L1) and second (L2) languages. This apprehension may intensify when participants communicate in the L2, especially if they believe their level of L2 competence to be very low. This study examines perceived competence in an L2 as a function of actual competence and language anxiety. Thirty-seven young adult Anglophone students, with widely varied competence in French, participated. They completed scales of language anxiety and a modified version of the “can-do” test, which assessed their self-perceptions of competence on 26 French tasks. They then attempted each of those tasks. We found that L2 language anxiety, perceived L2 competence, and actual L2 competence intercorrelated. However, regression analysis with actual proficiency level controlled showed that anxious students tended to underestimate their competence relative to less anxious students, who tended to overestimate their competence. Theoretical and practical implications are discussed.
646 citations
TL;DR: Under certain conditions that challenge ion regulation, chloride cells proliferate on the lamellae, which causes a thickening of the blood-to-water diffusion barrier and thus impedes respiratory gas transfer.
Abstract: This review focuses on the structure and function of the branchial chloride cell in freshwater fishes. The mitochondria-rich chloride cell is believed to be the principal site of trans-epithelial Ca2+ and Cl- influxes. Though currently debated, there is accruing evidence that the pavement cell is the site of Na+ uptake via channels linked electrically to an apical membrane vacuolar H(+)-ATPase (proton pump). Chloride cells perform an integral role in acid-base regulation. During conditions of alkalosis, the surface area of exposed chloride cells is increased, which serves to enhance base equivalent excretion as the rate of Cl-/HCO3- exchange is increased. Conversely, during acidosis, the chloride cell surface area is diminished by an expansion of the adjacent pavement cells. This response reduces the number of functional Cl-/HCO3- exchangers. Under certain conditions that challenge ion regulation, chloride cells proliferate on the lamellae. This response, while optimizing the Ca2+ and Cl- transport capacity of the gill, causes a thickening of the blood-to-water diffusion barrier and thus impedes respiratory gas transfer.
543 citations
TL;DR: By identifying and measuring the essential organizational characteristics and management practices that promote organizational learning, one could develop a benchmark of learning capability that would enable managers to design interventions to overcome specific barriers in building a learning organization.
536 citations
TL;DR: Filtration of recombinant human BDNF or NT-4/5 into the vicinity of the axotomized RSNs, between days 7 and 14 after axotomy, fully prevented their atrophy and was still evident 2 weeks after the termination of BDNF treatment.
Abstract: Rubrospinal neurons (RSNs) undergo a marked atrophy in the second week after cervical axotomy. This delayed atrophy is accompanied by a decline in the expression of regeneration-associated genes such as GAP-43 and Talpha1-tubulin, which are initially elevated after injury. These responses may reflect a deficiency in the trophic support of axotomized RSNs. To test this hypothesis, we first analyzed the expression of mRNAs encoding the trk family of neurotrophin receptors. In situ hybridization revealed expression of full-length trkB receptors in virtually all RSNs, which declined 7 d after axotomy. Full-length trkC mRNA was expressed at low levels. Using RT-PCR, we found that mRNAs encoding trkC isoforms with kinase domain inserts were present at levels comparable to that for the unmodified receptor. TrkA mRNA expression was not detected in RSNs, and the expression of p75 was restricted to a small subpopulation of axotomized cells. In agreement with the pattern of trk receptor expression, infusion of recombinant human BDNF or NT-4/5 into the vicinity of the axotomized RSNs, between days 7 and 14 after axotomy, fully prevented their atrophy. This effect was still evident 2 weeks after the termination of BDNF treatment. Moreover, BDNF or NT-4/5 treatment stimulated the expression of GAP-43 and Talpha1-tubulin mRNA and maintained the level of trkB expression. Vehicle, NGF, or NT-3 treatment had no significant effect on cell size or GAP-43 and Talpha1-tubulin expression. In a separate experiment, infusion of BDNF also was found to increase the number of axotomized RSNs that regenerated into a peripheral nerve graft. Thus, in BDNF-treated animals, the prevention of neuronal atrophy and the stimulation GAP-43 and Talpha1-tubulin expression is correlated with an increased regenerative capacity of axotomized RSNs.
TL;DR: A strategy of initial revascularization appears to improve the prognosis of this population compared with angina-guided medical therapy, and a larger long-term study is needed to confirm this benefit and to adequately test the potential of more aggressive drug therapy.
Abstract: Background Patients with ischemia during stress testing and ambulatory ECG monitoring have an increased risk of cardiac events, but it is not known whether their prognosis is improved by more aggressive treatment with anti-ischemic drugs or revascularization. Methods and Results The Asymptomatic Cardiac Ischemia Pilot study randomized 558 such patients who had coronary anatomy suitable for revascularization to three treatment strategies: angina-guided drug therapy (n=183), angina plus ischemia–guided drug therapy (n=183), or revascularization by angioplasty or bypass surgery (n=192). Two years after randomization, the total mortality was 6.6% in the angina-guided strategy, 4.4% in the ischemia-guided strategy, and 1.1% in the revascularization strategy (P<.02). The rate of death or myocardial infarction was 12.1% in the angina-guided strategy, 8.8% in the ischemia-guided strategy, and 4.7% in the revascularization strategy (P<.04). The rate of death, myocardial infarction, or recurrent cardiac hospitaliza...
TL;DR: In this paper, the authors examined the relationship between the richness of four different wetland taxa (birds, mammals, herptiles, and plants) in 30 southeastern Ontario, Canada wetlands and two anthropogenic factors: road construction and forest removal/conversion on adjacent lands.
Abstract: We examined the relationship between the richness of four different wetland taxa (birds, mammals, herptiles, and plants) in 30 southeastern Ontario, Canada wetlands and two anthropogenic factors: road construction and forest removal/conversion on adjacent lands. Data were obtained from two sources: road densities and forest cover from 1:50,000 Government of Canada topographic maps and species lists and wetland areas from Ontario Ministry of Natural Resources wetland evaluation reports. Multiple regression analysis was used to model the relationships between species richness and wetland area, road density, and forest cover. Our results show a strong positive relationship between wetland area and species richness for all taxa. The species richness of all taxa except mammals was negatively correlated with the density of paved roads on lands up to 2 km from the wetland. Furthermore, both herptile and mammal species richness showed a strong positive correlation with the proportion of forest cover on lands within 2 km. These results provide evidence that at the landscape level, road construction and forest removal on adjacent lands pose significant risks to wetland biodiversity. Furthermore, they suggest that most existing wetland policies, which focus almost exclusively on activities within the wetland itself and/or a narrow buffer zone around the wetland perimeter, are unlikely to provide adequate protection for wetland biodiversity.
TL;DR: This paper reported on a study of the relationship between the types of listening comprehension strategies reported, the frequency of their use, and the differences in reported use across four variables: level of language proficiency, gender, listening ability, and learning style.
Abstract: This paper reports on a study of the relationship between the types of listening comprehension strategies reported, the frequency of their use, and the differences in reported use across four variables: level of language proficiency, gender, listening ability, and learning style. High school students of French reported on their thought processes during a think-aloud procedure. All students reported using metacognitive and cognitive strategies, with an overall increase in total number of strategies reported by proficiency level. Results indicate clear differences in reported strategy use by listening ability and proficiency level. The use of metacognitive strategies, such as comprehension monitoring, problem identification, and selective attention appeared to be the significant factor distinguishing the successful from the less successful listener. Differences for gender were minimal, and differences for learning style were inconclusive. A qualitative analysis of representative protocols also pointed to the integral role of metacognitive strategies as well as differences in the use of prior knowledge, inferencing, prediction skills, and monitoring. Results are discussed in the light of information-processing theory. Implications for pedagogy conclude the paper.
TL;DR: In this article, the authors introduce a new approach to decompose the Gini ratio into three components, supporting them with economic and statistical rigorous interpretations, which are weighted by the product of the population shares times the income shares of the corresponding subpopulations where the weights add to one.
Abstract: The purpose of this research is to introduce a new approach to the decomposition of the Gini ratio into three components, supporting them with economic and statistical rigorous interpretations. The three components are: (i) the Gini inequality within subpopulations; (ii) the net contribution of the extended Gini inequality between subpopulations; and (iii) the contribution of the intensity of transvariation between subpopulations. These components are weighted by the product of the population shares times the income shares of the corresponding subpopulations where the weights add to one.
TL;DR: It is believed that the high rate of occurrence of the condition in immediate relatives justifies echocardiographic screening of first-degree relatives to anticipate and prevent future complications associated with this common cardiac malformation.
TL;DR: Despite frequent interactions with the health care system, too many Canadians are still not well controlled or are unaware of their hypertension.
TL;DR: It is concluded that anemia increases the risk of death in critically ill patients with cardiac disease and blood transfusions appear to decrease this risk.
Abstract: In 4,470 critically ill patients, we examined the impact of transfusion practice on mortality rates. As compared with survivors, patients who died in intensive care units (ICU) had lower hemoglobin values (95 +/- 26 versus 104 +/- 23 g/L, p 20), and a cardiac diagnosis had a significantly lower mortality rate when given 1 to 3 or 4 to 6 units of allogeneic red cells (55% [no transfusions] versus 35% [1 to 3 units] or 32% [4 to 6 units], respectively, p = 0.01). Adjusted odds ratio (OR) predicting survival were 0.61 (95% CI; 0.37 to 1.00, p = 0.026) after 1 to 3 units and 0.49 (95% CI; 0.23 to 1.03, p = 0.03) after 4 to 6 units compared with nontransfused anemic patients. In the subgroup with cardiac disease, increasing hemoglobin values in anemic patients was associated with improved survival (OR = 0.80 for each 10 g/L increase, p = 0.012). We conclude that anemia increases the risk of death in critically ill patients with cardiac disease. Blood transfusions appear to decrease this risk.
TL;DR: In this paper, meta-analyses of randomized trials evaluating the efficacy and safety of aprotinin, desmopressin, tranexamic acid, and epsilon-aminocaproic a
Abstract: Concern about the side effects of allogeneic red blood cell transfusion has increased interest in methods of minimizing perioperative transfusion.We performed meta-analyses of randomized trials evaluating the efficacy and safety of aprotinin, desmopressin, tranexamic acid, and epsilon-aminocaproic a
TL;DR: Should conservative treatment fail, surgical removal may be indicated during the formative phase, but only under exceptional circumstances during the resorptive phase, and aspiration and lavage of the deposit should be performed only during the latter phase.
Abstract: Calcific tendinopathy, or calcifying tendinitis, is a disease characterized by multifocal, cell-mediated calcification of living tissue. After spontaneous disappearance of the calcific deposits or, less frequently, surgical removal, the tendon reconstitutes itself. Attention to the clinical presentation and the radiologic, morphologic, and gross characteristics of the calcium deposit will facilitate differentiation between the formative phase and the resorptive phase, which is of paramount importance in the management of this disease. Should conservative treatment fail, surgical removal may be indicated during the formative phase, but only under exceptional circumstances during the resorptive phase. Aspiration and lavage of the deposit should be performed only during the latter phase.
TL;DR: The 3MS was superior to the MMSE, justifying the slightly greater burden for its administration and scoring, and neither test worked well in identifying lower levels of cognitive impairment.
Journal Article•
TL;DR: A critical survey of existing literature on content-based indexing techniques is provided to point out the relative advantages and disadvantages of each approach.
23 Apr 1997
TL;DR: This paper discusses one essential trouble brought about by imbalanced training sets and presents a learning algorithm addressing this issue.
Abstract: Existing concept learning systems can fail when the negative examples heavily outnumber the positive examples. The paper discusses one essential trouble brought about by imbalanced training sets and presents a learning algorithm addressing this issue. The experiments (with synthetic and real-world data) focus on 2-class problems with examples described with binary and continuous attributes.
TL;DR: In this article, several mechanisms of self-discharge are distinguished and the resulting forms of the change of potential on open-circuit with time or log time provide a means of identifying the type of selfdischarge process that occurs.
TL;DR: The high mortality rate, the severity of the infection in infants, plus the scarcity of information on the ecology and pathogenicity of this organism warranted a review of the clinical and microbiological features of this putative foodborne pathogen.
TL;DR: It is shown that transient forebrain ischemia selectively elevates levels of neuronal apoptosis inhibitory protein (NAIP) in rat neurons that are resistant to the injurious effects of this treatment, suggesting that NAIP may play a key role in conferring resistance to ischemic damage and that treatments that elevate neuronal levels of this antiapoptotic protein may have utility in the treatment of stroke.
Abstract: We show here that transient forebrain ischemia selectively elevates levels of neuronal apoptosis inhibitory protein (NAIP) in rat neurons that are resistant to the injurious effects of this treatment. This observation suggests that increasing NAIP levels may confer protection against ischemic cell death. Consistent with this proposal, we demonstrate that two other treatments that increase neuronal NAIP levels, systemic administration of the bacterial alkaloid K2S2a and intracerebral injection of an adenovirus vector capable of overexpressing NAIP in vivo, reduce ischemic damage in the rat hippocampus. Taken together, these findings suggest that NAIP may play a key role in conferring resistance to ischemic damage and that treatments that elevate neuronal levels of this antiapoptotic protein may have utility in the treatment of stroke.
TL;DR: Overall, therapeutic alliance predicted successful outcome; the task dimension of the alliance in particular predicted couples' satisfaction; one dimension of female partners' trust, their faith in their partner, predicted couples'?
Abstract: This study examined client variables expected to predict success in emotionally focused marital therapy (EFT), now the second most validated form of marital therapy after the behavioral approaches. The relationship of attachment quality, level of emotional self-disclosure, level of interpersonal trust, and traditionality to the therapy outcome variables, marital adjustment, intimacy, and therapist ratings of improvement, was examined. These variables were chosen for their relevance to the theory and practice of EFT and to intimate relationships in general. Overall, therapeutic alliance predicted successful outcome; the task dimension of the alliance in particular predicted couples' satisfaction. More specifically, one dimension of female partners' trust, their faith in their partner, predicted couples' satisfaction at follow-up. Females' faith also significantly predicted males' level of intimacy at follow-up. Males who were most likely to be nondistressed at termination indicated higher levels of proximity seeking on an attachment measure at intake, and older males and males whose partners had higher levels of faith in them were more likely to be nondistressed at follow-up. Traditionality was not found to be significantly related to outcome. Couples who made the most gains at follow-up also indicated lower initial marital satisfaction and included males who indicated lower levels of use of attachment figure on the attachment measure at intake. Males who made the largest gains at termination were older and were rated as less expressive by their partner on self-disclosure measures at intake. Age was the only variable significantly related to males' gains in satisfaction at follow-up. Implications for the practice of marital therapy and future research are delineated.
TL;DR: Correlations among the subscales revealed a simplex pattern that provides support for the self-determination continuum and the construct validity of the scale, and implications for research on client motivation for therapy are discussed.
Abstract: The purpose of this study was to examine the psychometric properties of a new measure of client motivation for therapy, the Client Motivation for Therapy Scale. This scale is designed to measure client's Intrinsic Motivation, four forms of regulation for Extrinsic Motivation (integrated, identified, introjected, and external regulation), and Amotivation for therapy. These subscales correspond to different forms of motivation identified by Deci and Ryan (1985) and fall along a self-determination continuum. An experimental version of the scale, along with related scales, was distributed to a total sample of 138 clients involved in therapy. The results supported the factor structure of the scale and revealed a satisfactory level of internal consistency. Correlations among the subscales revealed a simplex pattern that, in general, provides support for the self-determination continuum and the construct validity of the scale. Implications for research on client motivation for therapy are discussed.