Showing papers by "University of Western Ontario published in 1994"
TL;DR: These comparisons are primarily empirical, and concentrate on the accuracy, reliability, and density of the velocity measurements; they show that performance can differ significantly among the techniques the authors implemented.
Abstract: While different optical flow techniques continue to appear, there has been a lack of quantitative evaluation of existing methods. For a common set of real and synthetic image sequences, we report the results of a number of regularly cited optical flow techniques, including instances of differential, matching, energy-based, and phase-based methods. Our comparisons are primarily empirical, and concentrate on the accuracy, reliability, and density of the velocity measurements; they show that performance can differ significantly among the techniques we implemented.
4,771 citations
TL;DR: The authors examined some of the more specific cognitive processes that may be involved in language acquisition in terms of a three-stage model of learning: Input, processing, and output, and developed a new anxiety scale to measure anxiety at each of the stages.
Abstract: Previous research has shown language anxiety to be associated with broad-based indices of language achievement, such as course grades. This study examined some of the more specific cognitive processes that may be involved in language acquisition in terms of a three-stage model of learning: Input, Processing, and Output. These stages were represented in a set of nine tasks that were employed to isolate and measure the language acquisition stages. A new anxiety scale was also developed to measure anxiety at each of the stages. Generally, significant correlations were obtained between the stage-specific anxiety scales and stage-specific tasks (e.g., output anxiety with output tasks) suggesting that the effects of language anxiety may be both pervasive and subtle.
1,126 citations
TL;DR: McNeill as discussed by the authors discusses what Gestures reveal about Thought in Hand and Mind: What Gestures Reveal about Thought. Chicago and London: University of Chicago Press, 1992. 416 pp.
Abstract: Hand and Mind: What Gestures Reveal about Thought. David McNeill. Chicago and London: University of Chicago Press, 1992. 416 pp.
988 citations
TL;DR: The Inflammatory Bowel Disease Questionnaire is a valid reliable assessment tool that reflects important changes in the health status of patients with IBD and should be used in future clinical trials in IBD.
677 citations
TL;DR: In this paper, the authors examined the relationship between ownership entry modes and performance, and developed a theoretical relationship for international entry modes that is based on the contingency characteristics of resource requirements and organizational control factors.
Abstract: This study examines the relationship between ownership entry modes and performance. The ownership entry modes examined are the wholly owned modes of acquisition and new venture entry, and the non-wholly owned mode of joint venture entry. A theoretical relationship is developed for international entry modes that is based on the contingency characteristics of resource requirements and organizational control factors. This model suggests that different entry modes have different performance outcomes based upon their resource and organizational control demands. The theoretical model, although developed using the eclectic theoretical approach, is based largely on concepts and relationships previously delineated in contingency theory. Our hypotheses suggest that new ventures should outperform joint ventures, and joint ventures should outperform acquisitions. An empirical test using a sample of 321 Japanese firms entering the North American market provides supporting evidence.
610 citations
TL;DR: It is recommended that when both interrater and intrarater reliability are being assessed, a repeated-measures design be used to take advantage of the increased precision gained by using all observations in the statistical analysis, and appropriate statistical tests, confidence intervals, and SEMs always be used in conjunction with the estimated reliability coefficients.
Abstract: Statistical methodology for the concurrent assessment of interrater and intrarater reliability is presented. Application of the methodology is illustrated with an example of one therapist using two goniometers repeatedly to measure knee joint angles. Methods for estimating the coefficients, testing hypotheses, constructing confidence intervals, and computing sample size requirements are provided. In addition, the calculation and clinical interpretation of the standard error of measurement (SEM) are discussed. It is recommended that (1) when both interrater and intrarater reliability are being assessed, a repeated-measures design be used to take advantage of the increased precision gained by using all observations in the statistical analysis, and (2) appropriate statistical tests, confidence intervals, and SEMs always be used in conjunction with the estimated reliability coefficients.
604 citations
TL;DR: This paper examined the relationship between the dependent variable of work-family conflict (operationalized as overload, work to family interference, family to work interference) and the independent variables of gender, family type, and perceived control.
Abstract: The objective of this research was to examine the relationships between the dependent variable of work-family conflict (operationalized as overload, work to family interference, family to work interference) and the independent variables of gender, family type, and perceived control. The sample consisted of 1,989 single-parent and dual-income employees with children ages 6 through 12. The findings indicated that individuals with higher perceived control have lower levels of overload and interference. Women had higher levels of overload and interference than did men. Single parents had similar levels of overload and interference from family to work as married individuals.
582 citations
TL;DR: In this paper, the effects of growth on long-run unemployment were analyzed using a search model of equilibrium unemployment, where growth arises explicitly from the introduction of new technologies that require labour reallocation for their implementation.
Abstract: This paper analyses the effects of growth on long-run unemployment using a search model of equilibrium unemployment where growth arises explicitly from the introduction of new technologies that require labour reallocation for their implementation. The analysis uncovers and compares between two competing effects of growth on unemployment. The first is a capitalisation effect, whereby an increase in growth raises the capitalised returns from creating jobs and consequently reduces the equilibrium rate of unemployment. The second is a creative destruction effect whereby an increase in growth reduces the duration of a job match, thereby raising the equilibrium level of unemployment both directly, by raising the job separation rate, and indirectly, by discouraging the creation of job vacancies. This paper asks the question of how the rate of economic growth affects unemployment in the long run. The main consideration that leads us to think that this is an interesting question has to do with the re-allocative aspect of growth. In the long run, faster economic growth must come from a faster increase in knowledge. To the extent that the advancement of knowledge is embodied in industrial innovations it is likely to raise the job-destruction rate, through automation, skill-obsolescence, and the bankruptcy associated with the process of creative destruction. In short, increased growth is likely to produce an increased rate of job-turnover, and the search theories of Lucas and Prescott (1974) and Pissarides (1990) imply that an increased rate of job-turnover will result in a higher natural rate of unemployment. This conclusion is also consistent with the empirical results of Davis and Haltiwanger (1990) which show that periods of high unemployment tend to be periods of high job-turnover at the establishment level. It suggests the possibility of a positive longrun tradeoff between growth and unemployment, at least over some range.' There has been relatively little attention paid to our question in the literature on longrun determinants of unemployment. For example, the recent empirical examination by Layard, Nickell and Jackman (1991) of unemployment rates among OECD countries did not even consider the rate of economic growth as a possible explanatory variable. This is consistent with the seminal theoretical work of Phelps (1968) which implies that the natural rate of unemployment is independent of the rate of productivity growth. The only
580 citations
Journal Article•
TL;DR: A newly described function for V EGF as a potent chemotaxin for endothelial cells as well as a role for VEGF in RA-associated endothelial migration and proliferation are elucidated.
Abstract: Angiogenesis is important in the proliferation of inflammatory synovial tissue. Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that is also angiogenic in vivo. We examined the potential role of VEGF in mediating chemotaxis and proliferation of endothelial cells in rheumatoid arthritis (RA) using samples of synovial tissue and synovial fluid from 55 arthritic patients. Synovial fluid VEGF by ELISA was higher in RA synovial fluids (386 +/- 122 ng/ml) (SE) compared with osteoarthritis (OA) synovial fluids (< 0.8 ng/ml) (p < 0.05) or synovial fluids from patients with other arthritides (6.6 +/- 2 ng/ml). In addition to its known mitogenic properties, we found that human rVEGF was chemotactic for HUVECs at concentrations above 0.02 nM. Incubation of RA synovial fluids with neutralizing anti-VEGF resulted in 23 to 66% (mean 53 +/- 4%) inhibition of HUVEC chemotaxis. Conditioned medium from four of five RA synovial tissue explants was mitogenic for bovine adrenal capillary endothelial cells. Anti-VEGF neutralized from 19 to 42% (mean 28 +/- 4%) of this mitogenic activity. To determine the cellular source of VEGF in synovial tissue, we employed immunohistochemistry. VEGF+ cells were rarely (< 1%+) found in normal synovial tissues. In contrast, RA and OA synovial tissues exhibited VEGF+ lining cells (8% and 13%, respectively). A few synovial tissue macrophages were VEGF+ in both RA and OA (5% and 2%, respectively). These results elucidate a newly described function for VEGF as a potent chemotaxin for endothelial cells as well as a role for VEGF in RA-associated endothelial migration and proliferation.
570 citations
TL;DR: The method of Parallel Factor Analysis, which simultaneously fits multiple two-way arrays or ‘slices’ of a three-way array in terms of a common set of factors with differing relative weights in each ‘slice’ is reviewed.
502 citations
TL;DR: In this paper, a model to explain performance in decision-making groups characterized by high diversity in composition is developed, where communication is proposed as an integrating mechanism, and a theory of communication in terms of preconditions is described.
Abstract: The purpose of this article is to develop a model to explain performance in decision-making groups characterized by high diversity in composition. It begins with a brief discussion on the nature and effects of diversity. Previous research on group performance is then reviewed with the general conclusion that diverse groups perform less well than homogeneous ones do. This conclusion is challenged by closely examining a small group of studies specifically researching the effects of diversity, and it is shown that diversity can enhance a group's performance if it is integrated. Communication is proposed as an integrating mechanism, and a theory of communication in terms of preconditions is described. This theory is then used to develop propositions concerning the relationships among diversity, integration, and performance in decision-making groups. Implications for research and practice are discussed.
TL;DR: The evidence supports both the views that depression promotes pain and pain promotes depression, and chronic pain was the most powerful variable.
Abstract: Chronic pain and depression often coexist, but there is still uncertainty about the nature of this relationship. Virtually all the available data are cross-sectional and therefore do not clarify the causal relationship between the two variables. In epidemiological studies, chronic pain has often been defined fairly liberally in terms of the actual duration. In this study, the definition of chronic pain was based upon self-reports of pain present for most of the days in at least 1 month of the 12 months preceding the interview. We tested the hypotheses that depression causes pain and that pain causes depression in a sample of 2324 subjects who were assessed for the presence of musculo-skeletal pain and the presence of depression, using for the latter a standardized published instrument called the Center for Epidemiologic Studies Depression scale (CES-D). The subjects were first examined using the National Health and Nutrition Survey (NHANES 1) of the United States National Center for Health Statistics from 1974 to 1975, and were followed-up from 1981 to 1984. Those with data on both occasions represent 76% of an initial population of 3059 persons. On logistic regression analysis depressive symptoms at year 1 significantly predicted the development of chronic musculo-skeletal pain at year 8 with an odds ratio of 2.14 for the depressed subjects compared with the non-depressed subjects. In patients in whom pain was present at baseline no socio-demographic variable alone predicted its persistence; however, male sex and white race together with 2 items of the CES-D did predict the persistence of existing pain.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Analysis using circularly polarized light has the ability to enhance histologic assessment of tissue and can provide additional insights into the composition and structure of myocardial collagen.
Abstract: Collagen plays a major role in the structural organization of the heart and therefore direct visualization of collagen fibers is a crucial component of cardiac analysis. Although linearly polarized light has proven an effective tool for the examination of myocardial collagen in histologic sections, the use of circularly polarized light may offer advantages and additional possibilities. We examined the potential enhancement of collagen analysis using circularly polarized light in two ways. We first measured the brightness, and hence indirectly assessed the birefringence, of collagen fibers in scars examined at different times after myocardial infarction. Secondly, we measured collagen content in myocardial tissue and compared results obtained from brightfield analysis of trichrome stained sections with those obtained from circularly polarized light analysis of picrosirius red stained sections. We observed a progressive increase in the maximum brightness of collagen fibers in the scar with time, and a time-dependent shift in the relative distribution of collagen fiber brightness from lower to higher levels. We found consistently lower values of collagen content in trichrome stained versus picrosirius red stained tissue, and concluded that trichrome staining underestimated collagen content. The information provided by these studies could not be obtained by brightfield analysis and could be only partially obtained from linearly polarized light analysis. Thus, analysis using circularly polarized light has the ability to enhance histologic assessment of tissue and can provide additional insights into the composition and structure of myocardial collagen.
TL;DR: The results of this study suggest that the mechanisms underlying the formation of perceptual representations of objects are quite independent of those mediating on-line visuomotor control.
TL;DR: Evidence is presented suggesting that the same dissociation between perception and action is evident in the visual processing of object shape as it is in the control of goal-directed grasping.
TL;DR: Findings indicate that osteopontin is a potent inhibitor of HA formation, which requires phosphate and carboxylate groups, possibly including the conserved sequence of contiguous aspartic acid residues.
Abstract: Osteopontin is a phosphorylated sialoprotein containing a conserved sequence of contiguous aspartic acid residues. This protein is expressed at high levels in mineralized tissues and has previously been shown to inhibit the in vitro formation of hydroxyapatite (HA). In the present study, protein modification and model compound studies have been used to identify the structural features of osteopontin that are responsible for its crystal-modulating properties. Using metastable calcium phosphate solutions buffered by autotitration, osteopontin caused half-maximal inhibition of HA formation at a concentration (IC50) of 0.06 microgram/ml. The hen egg yolk phosphoprotein phosvitin was a much weaker inhibitor, while dextran sulphate had no effect. The synthetic polypeptide poly(aspartic acid) was almost as effective an inhibitor of HA formation as osteopontin (IC50 0.11 microgram/ml), whereas poly(glutamic acid) was more than a thousand times less potent (IC50 155 micrograms/ml). In a steady-state agarose gel system, much higher polypeptide concentrations were required for inhibition of HA formation, but a similar relative order of inhibitory effectiveness was observed. Treatment of osteopontin with alkaline phosphatase removed 84% of the covalently bound phosphate and reduced its HA-inhibiting activity by more than 40-fold. Treatment with glycine ethyl ester in the presence of carbodi-imide modified 86% of the carboxylate groups in osteopontin and reduced its inhibitory activity by 6-fold. These findings indicate that osteopontin is a potent inhibitor of HA formation. This activity requires phosphate and carboxylate groups, possibly including the conserved sequence of contiguous aspartic acid residues. Osteopontin may act as an inhibitor of phase separation in physiological fluids of high supersaturation.
TL;DR: The diagnoses of 40,000 consecutively accessioned oral biopsies from the Oral Pathology Diagnostic Service, University of Western Ontario, London, Canada, were reviewed to allow clinicians to make realistic judgments in counseling patients before biopsy about the probability of diagnosis and risks associated with nonspecific clinical or radiographic lesions.
TL;DR: The rate and duration of response of anaplastic oligodendrogliomas to a dose-escalated combination chemotherapy regimen consisting of procarbazine, lomustine, and vincristine and the side effects of this treatment were examined.
Abstract: PURPOSETo examine the rate and duration of response of anaplastic oligodendrogliomas to a dose-escalated combination chemotherapy regimen consisting of procarbazine, lomustine (CCNU), and vincristine (PCV) and to evaluate the side effects of this treatment.METHODSIn this single-arm multicentered phase II study, patients with measurable, newly diagnosed or recurrent, contrast-enhancing anaplastic oligodendrogliomas were treated with up to six cycles of PCV. Central pathology and radiology review were mandatory, and rigorous response criteria based on imaging were used.RESULTSThirty-three patients entered the trial; nine were excluded subsequently, seven due to ineligible pathology. Eighteen of 24 eligible patients (75%) responded, nine completely (38%), four had stable disease (SD), and two progressed during the first cycle of PCV. Responses were observed in nine of 10 patients (90%) with a preexisting low-grade oligodendroglioma and 10 of 15 (67%) with necrotic tumors, called glioblastoma multiforme by so...
TL;DR: Although treatment was not associated with any improvement in symptoms, ursodeoxycholic acid therapy caused the bilirubin to fall significantly within the first 3 mo of therapy (p<0.001), which led to an improvement in serum markers of cholestasis.
TL;DR: It is shown that the number of states that is sufficient and necessary in the worst case for a deterministic finite automaton (DFA) to accept the catenation of an m-state DFA language and an n-stateDFA language is exactly m2n − 2n − 1, for m, n ⩾ 1.
TL;DR: In this article, the first spectroscopic evidence to indicate Fe(III)-oxyhydroxide species forming in pyrrhotite has been presented, based on X-ray photoelectron spectroscopy and Auger Electron Spectroscopy (AES).
TL;DR: In this paper, the finite sample properties of Generalized Method of Moments (GMM) in an asset pricing context were investigated and it was shown that a two-stage GMM approach produces goodness-of-fit statistics that reject the restrictions too often.
TL;DR: It is shown here that chemical modification of carboxylate groups abolishes the nucleation activity of BSP, but enzymic dephosphorylation has no effect, and it is proposed that polycarboxylates represent a general site for growth-modulating interactions between proteins and biological crystals.
Abstract: Bone sialoprotein (BSP) is a bone-specific glycoprotein containing phosphoserine and sulphotyrosine residues and regions of contiguous glutamic acid residues. Recent studies in this laboratory have shown that BSP is capable of nucleating the bone mineral hydroxyapatite in a steady-state agarose gel system. We show here that chemical modification of carboxylate groups abolishes the nucleation activity of BSP, but enzymic dephosphorylation has no effect. Formation of hydroxyapatite is also induced by poly(L-glutamic acid) and poly(D-glutamic acid), but not by poly(L-aspartic acid) or poly(L-lysine). Calreticulin, a muscle protein with short sequences of contiguous glutamic acid residues, also lacks nucleation activity. These findings suggest that the nucleation of hydroxyapatite by BSP involves one or both of the glutamic acid-rich sequences. Based on these findings and others, we propose that polycarboxylate sequences represent a general site for growth-modulating interactions between proteins and biological crystals.
TL;DR: The data confirm the short-term efficacy of amitriptyline and cyclobenzaprine in a small percentage of patients with fibromyalgia and predictors of response to these drugs could not be determined.
Abstract: Objective. To compare the relative efficacy and tolerability of amitriptyline, cyclobenzaprine, and placebo in the treatment of fibromyalgia, and to identify predictors of response to amitriptyline and cyclobenzaprine.
Methods, Two hundred eight patients who fulfilled the American College of Rheumatology criteria for the classification of fibromyalgia were entered into a 6-month prospective, double-blind, multicenter trial and were randomized to 1 of 3 treatment groups: amitriptyline, cyclobenzaprine, or placebo.
Results. After 1 month, 21%, 12%, and 0% of the amitriptyline, cyclobenzaprine, and placebo patients, respectively, had significant clinical improvement (amitriptyline versus placebo P = 0.002, cyclobenzaprine versus placebo P = 0.02, amitriptyline versus cyclobenzaprine P not significant). These percentages increased to 36%, 33%, and 19%, respectively, at the 6-month assessment (P not significant). The nature and frequency of side effects reported by patients treated with amitriptyline and those reported by patients treated with cyclobenzaprine were similar. A normal Minnesota Multiphasic Personality Inventory (MMPI) profile at baseline was predictive of clinical improvement at the 1-month evaluation (odds ratio 3.3, 95% confidence interval 1.2—9.0). However, neither the MMPI profile nor any of the demographic, clinical, or functional parameters evaluated at baseline predicted long-term response.
Conclusion. Our data confirm the short-term efficacy of amitriptyline and cyclobenzaprine in a small percentage of patients with fibromyalgia. Long-term efficacy could not be demonstrated because of a higher-than-expected placebo response. Predictors of response to these drugs could not be determined.
TL;DR: In this paper, the X-ray photoelectron (XPS) spectrum of pyrite fracture surfaces, exposed for 7 h to water vapour at low pressure (10−5 Pa), showed no change to their Fe(2p) or S(2 p) X-Ray photoelectRON (Xps) spectrum, but oxygen deposition occurs as H2O, OH− and O2− (74, 19, and 7%, respectively).
TL;DR: Investigation of the frequency of siderophore production in iron-deficient culture of freshwater and marine cyanobacteria and the effects of extracellular iron chelators on iron uptake in a coccoid marine species confirm that iron chelate production is prevalent amongfreshwater and marine species and that some of these ironChelators function as siders.
Abstract: During periods when levels of biologically available iron are low, cyanobacteria produce low-molecular-weight ferric-specific chelators (siderophores). We investigated the frequency of siderophore production in iron-deficient culture of freshwater and marine cyanobacteria and examined the effects of extracellular iron chelators on iron uptake in a coccoid marine species. The results confirm that iron chelate production is prevalent among freshwater and marine species and that some of these iron chelators function as siderophores. The frequent identification of catechol-type siderophores further indicates that these iron chelators may be as important in high-affinity iron transport as are the hydroxamic acid-type siderophores.
TL;DR: A meta analysis of the strange situation, Child Develop ment, 59, 147-156(1988) as discussed by the authors showed that mothers' temperamental predictors of attachment are significantly more likely to be temperamental than infants' attachment to their fathers.
Abstract: cal Study of the Strange Situation (Erlbaum, Hills dale, NJ, 1978). 7. N.A. Fox, N.L. Kimmerly, and W.D. Sch?fer, Attachment to mother/attachment to father: A meta analysis, Child Development, 62, 210-225 (1991). 8. M.H. van Ijzendoom and P.M. Kroonen berg, Cross-cultural patterns of attachment: A meta analysis of the strange situation, Child Develop ment, 59, 147-156(1988). 9. H.H. Goldsmith and J.A. Alansky, Maternal and infant temperamental predictors of attachment: A meta-analytic review, Journal of Consulting and Clinical Psychology, 55, 805-816 (1987).
TL;DR: Higher vigour of seedlings, larger seed size and seed polymorphism were also of adaptive significance to the species, and plants responded to salt spray by inhibition of seed germination, developing resistance, increase in leaf thickness and reduced uptake of Na and Cl ions.
Abstract: Studies on the survival and establishment of seedlings in coastal and lacustrine sand dune systems suggest that nutrient deficiency, lack of moisture, sand accretion, salt spray and predation are probably the most important limiting factors. Seedlings employ both avoidance and tolerance strategies to with-stand the different stresses. For example, seedling recruitment of dune species coincided with periods of high moisture availability and occurred in years with high well distributed rainfall. The seedlings exhibited rapid vertical elongation of roots, avoided moisture stress by leaf rolling, dense hair on leaves, fleshy cotyledonary leaves, and by growing in the shade of nurse plants. A certain proportion of seedlings of all species survived partial burial and showed stimulation of leaf growth, total leaf area, number of tillers and total dry matter. Seedlings of most species could not survive complete burial, however, some species did grow through the sand deposit by an increase in the number of nodes and length of internodes. Plants responded to salt spray by inhibition of seed germination, developing resistance, increase in leaf thickness and reduced uptake of Na and Cl ions. Several characters such as higher vigour of seedlings, larger seed size and seed polymorphism were also of adaptive significance to the species.
TL;DR: This note is presented in advance of discussions by the International Committee on Systematic Bacteriology at the forthcoming congress (July 1994) so that there may be discussions and reaction by colleagues.
Abstract: The problem that the proposal for recording the properties of putative taxa of procaryotes attempts to redress arises because the International Code of Nomenclature of Bacteria is not able to provide sensible regulation of nomenclature for new taxa defined by very limited data, such as a nucleotide sequence for a small portion of the genome. The constructors of the original code (1957) and the Judicial Commission considering the 1976 and 1990 revisions did not foresee or act upon the possibilities for molecular description and typification of procaryotes that were not yet cultivable. As a result, formal names are being proposed for uncultivated procaryotes whose uniqueness is defined only by very limited characteristics, such as differences in a molecular sequence. As the editors of two journals concerned with the systematics of procaryotes, we recognize that the problem will increase as the available technology gains wider use and becomes easier to apply. Accordingly, this note is presented in advance of discussions by the International Committee on Systematic Bacteriology at the forthcoming congress (July 1994) so that there may be discussions and reaction by colleagues.