Showing papers by "University of British Columbia published in 1990"

Structural Model Evaluation and Modification: An Interval Estimation Approach.

Abstract: Dans les differentes procedures existantes pour l'evaluation et les modifications sequentielles des modeles structuraux, l'auteur s'attache a discuter celle connue sous le terme PMM. Plus generalement, les propositions de KAPLAN (1990) sont critiquees dans le detail

Avoidance of Intimacy: An Attachment Perspective

Abstract: A basic principle of attachment theory is that early attachment relationships with caregivers provide the prototype for later social relations. Working within an attachment framework, a new 4-group model of characteristic attachment styles in adulthood is proposed. In particular, two forms of adult avoidance of intimacy are differentiated: a fearful style that is characterized by a conscious desire for social contact which is inhibited by fears of its consequences, and a dismissing style that is characterized by a defensive denial of the need or desire for greater social contact. This distinction corresponds to two differing models of the self: people who fearfully avoid intimacy view themselves as undeserving of the love and support of others, and people who dismiss intimacy possess a positive model of the self that minimizes the subjective awareness of distress or social needs. The emotional and interpersonal ramifications of the two proposed styles of adult avoidance are discussed.

A cochlear frequency‐position function for several species—29 years later

Abstract: Accurate cochlear frequency-position functions based on physiological data would facilitate the interpretation of physiological and psychoacoustic data within and across species. Such functions might aid in developing cochlear models, and cochlear coordinates could provide potentially useful spectral transforms of speech and other acoustic signals. In 1961, an almost-exponential function was developed (Greenwood, 1961b, 1974) by integrating an exponential function fitted to a subset of frequency resolution-integration estimates (critical bandwidths). The resulting frequency-position function was found to fit cochlear observations on human cadaver ears quite well and, with changes of constants, those on elephant, cow, guinea pig, rat, mouse, and chicken (Bekesy, 1960), as well as in vivo (behavioral-anatomical) data on cats (Schucknecht, 1953). Since 1961, new mechanical and other physiological data have appeared on the human, cat, guinea pig, chinchilla, monkey, and gerbil. It is shown here that the newer extended data on human cadaver ears and from living animal preparations are quite well fit by the same basic function. The function essentially requires only empirical adjustment of a single parameter to set an upper frequency limit, while a "slope" parameter can be left constant if cochlear partition length is normalized to 1 or scaled if distance is specified in physical units. Constancy of slope and form in dead and living ears and across species increases the probability that the function fitting human cadaver data may apply as well to the living human ear. This prospect increases the function's value in plotting auditory data and in modeling concerned with speech and other bioacoustic signals, since it fits the available physiological data well and, consequently (if those data are correct), remains independent of, and an appropriate means to examine, psychoacoustic data and assumptions.

Large‐Scale Management Experiments and Learning by Doing

Abstract: Even unmanaged ecosystems are characterized by combinations of stability and instability and by unexpected shifts in behavior from both internal and external causes. That is even more true of ecosystems managed for the production of food or fiber. Data are sparse, knowledge of processes limited, and the act of management changes the system being managed. Surprise and change is inevitable. Here we review methods to develop, screen, and evaluate alternatives in a process where management itself becomes partner with science by designing probes that produce updated understanding as well as economic product. See full-text article at JSTOR

Self-esteem and clarity of the self-concept.

Abstract: This article examines the association between evaluative and knowledge components of the self. Four studies tested the hypothesis that the self-concepts of low-self-esteem (LSE) people are characterized by less clarity or certainty than those of high-self-esteem (HSE) people. LSE Ss exhibited less extremity and self-reported confidence when rating themselves on bipolar trait adjectives (Study 1), less temporal stability in their trait ratings over a 2-month interval (Study 2), less congruence between their self-concepts and their subsequent perceptions of situation-specific behavior and memory for prior behavior (Study 3), and less internal consistency, lower self-rated confidence, and longer reaction times when making me/not me responses to pairs of opposite traits (Study 4). Alternative accounts of the results and the implications of self-concept clarity for understanding the pervasive impact of self-esteem on behavior are discussed.

Entropy-driven tension and bending elasticity in condensed-fluid membranes.

Abstract: Sensitive micropipet methods have been used to measure the relation between tension and the projected surface area in fluid membranes of vesicles over a 4-order-of-magnitude range in tension (10 −3 -10 dyn/cm). In the low-tension regime (<0.5 dyn/cm), the data confirm the prediction of equilibrium theory that the projected area should increase logarithmically with tension as shape fluctuations become progressively restricted

Quasi-States: Sovereignty, International Relations and the Third World

Abstract: Introduction 1. States and quasi-states 2. A new sovereignty regime 3. Sovereignty regimes in history 4. Independence by right 5. Sovereignty and development 6. Sovereign rights versus development 7. Quasi-states and international history Conclusion.

Construction of Circumplex Scales for the Inventory of Interpersonal Problems

Abstract: We constructed a set of circumplex scales for the Inventory of Interpersonal Problems (IIP; Horowitz, Rosenberg, Baer, Ureno, & Villasenor, 1988) Initial scale construction used all 127 items from this instrument in two samples of university undergraduates (n = 197; n = 273) Cross-sample stability of item locations plotted against the first two principal components was high A final set of eight 8-item circumplex scales was derived from the combined sample (n = 470) and cross-validated in a third university sample (n = 974) Finally, we examined the structural convergence of the IIP circumplex scales with an established measure of interpersonal dispositions, the Revised Interpersonal Adjective Scales (IAS-R; Wiggins, Trapnell, & Phillips, 1988) Although both circumplex instruments were derived independently, they shared a common Circular space Implications of these results are discussed with reference to current research methods for the study of interpersonal behavior

Preliminary evaluation of a scheme for grading the gross morphology of the human intervertebral disc

Abstract: A five-category grading scheme for assessing the gross morphology of midsagittal sections of the human lumbar intervertebral disc was developed. The ability of three observers to categorize a series of 68 discs with a wide spectrum of morphologies established the comprehensiveness of the classificat

The Affective Consequences of Social Comparison: Either Direction Has Its Ups and Downs

Abstract: Research on social comparison processes has assumed that a comparison in a given direction (upward or downward) will lead to a particular affective reaction. In contrast, the present two studies proposed and found that a comparison can produce either positive or negative feelings about oneself, independent of its direction. Several factors moderated the tendency to derive positive or negative alfect from upward and downward comparisons. In Study l, cancer patients low in self-esteem and with low perceived control over their symptoms and illness were more likely to see downward comparisons as having negative implications for themselves. Those low in self-esteem were also more likely to perceive upward comparisons as negative. In Study 2, individuals with high marital dissatisfaction and those who felt uncertain about their marital relationship were morc likely to experience negative affect from upward and downward comparisons. The implications of these findings for social comparison theory and for the coping and adaptation literature arc discussed.

The revised Psychopathy Checklist: Reliability and factor structure.

Abstract: The revised Psychopathy Checklist (PCL) is a 20-item scale scored from interview and file information. Analyses of data from 5 prison samples (N= 92 5) and 3 forensic psychiatric samples (N= 356) indicate that the revised PCL resembles its 22-item predecessor in all important respects. It has excellent psychometric properties, and it measures 2 correlated factors that were cross-validated both within and between samples. Correlations between the original PCL and the revised version approached unity for both the factors and the full scale. We conclude that the revised PCL measures the same construct as the original and that the PCL is a reliable and valid instrument for the assessment of psychopathy in male forensic populations.

Rating the burn scar.

Abstract: A reliable, objective, and universal method of assessing burn scars does not exist in today's burn literature. Such a method is necessary to provide a descriptive terminology for the comparison of burn scars and the results of treatment. The method should be applicable to patients both within an institution and between burn centers. A burn scar assessment has been devised based on physical parameters. These relate to the healing and maturation of wounds, cosmetic appearance, and the function of the healed skin. Pigmentation, vascularity, pliability, and scar height are assessed independently, with increasing score being assigned to the greater pathologic condition. Normal skin has a score of 0. Seventy-three patients were assessed by three separate occupational therapists and the findings subjected to statistical analysis for interrater reliability. For each parameter a Cohen's kappa statistic of approximately 0.5 +/- 0.1 indicates a statistically significant agreement between observers. These values were found to improve with time. This appears to be a useful tool for the assessment of burn scars, allowing objective comparison of the same scar by different observers.

Extension of the Interpersonal Adjective Scales to include the Big Five dimensions of personality.

Abstract: Recent recognition that the dominance and nurturance dimensions of the interpersonal circumplex correspond closely to the surgency/extraversion and agreeableness dimensions of the five-factor model of personality provides an occasion for the closer integration of these two traditions. We describe the procedures whereby we extended our adjectival measure of the circumplex Revised Interpersonal Adjective Scales (IAS-R) to include the additional Big Five dimensions of conscientiousness, neuroticism, and openness to experience. The resultant five-scale instrument (IASR-B5) was found to have excellent structure on the item level, internally consistent scales, and promising convergent and discriminant properties when compared with the NEO Personality Inventory and the Hogan Personality Inventory. The unique feature of the IASR-B5 is that it provides a highly efficient instrument for combined circumplex and five-factor assessment. We provide an example of such combined assessment. The current decade in personality psychology has been characterized by renewed interest in two structural models that have been well-established for almost 40 years: the five-factor model of personality and the circumplex model of interpersonal behavior. The five orthogonal factors that have been found within the former tradition are listed in Figure 1. These dimensions originated in the work of Cattell (1946), were developed by Tupes and Christal (1961), and were refined by Norman (1963). Recent extensions of this line of investigation may be found in the work of McCrae and Costa (1985a), Digman and Inouye (1986), Hogan (1983), and Peabody and Goldberg (1989).

An ontological model of an information system

Abstract: An ontological model of an information system that provides precise definitions of fundamental concepts like system, subsystem, and coupling is proposed. This model is used to analyze some static and dynamic properties of an information system and to examine the question of what constitutes a good decomposition of an information system. Some of the major types of information system formalisms that bear on the authors' goals and their respective strengths and weaknesses relative to the model are briefly reviewed. Also articulated are some of the fundamental notions that underlie the model. Those basic notions are then used to examine the nature and some dynamics of system decomposition. The model's predictive power is discussed. >

Genomic imprinting: review and relevance to human diseases.

Abstract: This paper will first examine the evidence concerning genomic imprinting which has been accumulated over the past few years and then explore how it may relate to human development and human diseases

Entrepreneurial ability, venture investments, and risk sharing

Abstract: A number of issues that relate to the desirability and implications of new venture financing are examined within a principal-agent framework that captures the essence of the relationship between entrepreneurs and venture capitalists. The model suggests: 1 As long as the skill levels of entrepreneurs are common knowledge, all will choose to involve venture capital investors, since the risk sharing provided by outside participation dominates the agency relationship that is created. 2 The less able entrepreneurs will choose to involve venture capitalists, whereas the more profitable ventures will be developed without external participation because of the adverse selection problem associated with asymmetric information. 3 If a costly signal is available that conveys the entrepreneur's ability, some entrepreneurs will invest in such a signal and then sell to investors; these entrepreneurs, however, need not be the more able ones. The implications for new venture financing of these and other findings are discussed and illustrated by example.

Research notes and communications management objectives in mergers and acquisitions

Abstract: A taxonomy of managerial goals in mergers and acquisitions is developed through a cluster analysis of data from interviews with merger and acquisition practitioners. These clusters of objectives overlap with some objectives cited for mergers and acquisitions in the academic literature, but the correspondence is not complete. Further analysis shows that different types of mergers and acquisitions are characterized by different managerial objectives. The implications of this research for the development of a contingency model of the relationship between managerial objectives and mergers and acquisitions are discussed.

A Better World or a Shattered Vision? Changes in Life Perspectives Following Victimization

Abstract: Previous research has separately documented positive (Taylor, 1983) and negative (Janoff-Bulman, 1989) changes in beliefs following victimization. An integration of these literatures is proposed, considering the coping responses of the victim, the area of belief examined, and attributes of the victimizing event as mediators of change valence. Fifty-five cancer patients were interviewed concerning changes experienced in self-views, views of the world, future plans, relationships, and activities/priorities following diagnosis. Changes in activities/priorities and relationships were primarily positive, whereas changes in views of the self, the world, and the future were affectively mixed. Active coping was associated with positive belief changes, as was use of multiple coping methods. In addition, respondents experiencing ongoing threat reported more negative changes than did those not under threat. Implications of the findings are discussed.

Measurement and correlates of sport-specific cognitive and somatic trait anxiety: The sport anxiety scale

Abstract: Previous research indicates the viability of a distinction between cognitive and somatic components of the anxiety response, and multidimensional anxiety scales have proven useful in relating cognitive and somatic anxiety to behavioral outcomes. This article describes the development and validation of a sport-specific measure of cognitive and somatic trait anxiety. The Sport Anxiety Scale measures individual differences in Somatic Anxiety and in two classes of cognitive anxiety, Worry and Concentration Disruption. Both exploratory and confirmatory factor analyses supported these dimensions in several different athlete samples. Psychometric properties of the Sport Anxiety Scale are described, as are its relations with other psychological measures and with precompetition affective state measures. In the last of the four studies reported, scores on the Concentration Disruption scale were negatively related to the performance of college football players over the course of a season. The studies sugges...

Improvement on cosmological chaotic inflation through nonminimal coupling

Abstract: Models of cosmological inflation are plagued with a severe and seemingly unavoidable problem: in order to produce density perturbations of an amplitude consistent with large-scale observations, the self-coupling $\ensuremath{\lambda}$ of the inflaton field has to be tuned to an excessively small value. In all these models, however, the scalar field is taken to be minimally coupled to the scalar curvature ($\ensuremath{\xi}=0$). It is shown here that in the more general case of nonminimal coupling ($\ensuremath{\xi}\ensuremath{ e}0$), and within the framework of Linde's chaotic inflation, the constraint on the self-coupling could be relaxed by several orders of magnitude. We are led to this conclusion by the combination of two key results. (1) Contrary to previous common belief, the curvature coupling $\ensuremath{\xi}$ can be almost arbitrarily large without upsetting the inflationary scenario. In fact, the larger $\ensuremath{\xi}$ is, the better the model behaves. (2) Considerations regarding the amplitude of density perturbations constrain the ratio $\frac{\ensuremath{\lambda}}{{\ensuremath{\xi}}^{2}}$ rather than $\ensuremath{\lambda}$. Thus, by a suitable choice of $\ensuremath{\xi}$, the self-coupling $\ensuremath{\lambda}$ can be made as large as desired. It is found that for large $\ensuremath{\xi}$ the amplitude of density perturbations is much smaller than in $\ensuremath{\xi}=0$ models: ${(\ensuremath{\delta}\frac{\ensuremath{\rho}}{\ensuremath{\rho}})|}_{\ensuremath{\xi}g1}\ensuremath{\approx}{(48N{\ensuremath{\xi}}^{2})}^{\ensuremath{-}\frac{1}{2}}{(\frac{\ensuremath{\delta}\ensuremath{\rho}}{\ensuremath{\rho}})|}_{\ensuremath{\xi}=0}$, where $N\ensuremath{\sim}70$. For example, this represents a drop of over 4 orders of magnitude for $\ensuremath{\xi}={10}^{3}$. This same value results in a dramatic 9 orders of magnitude weakening of the constraint on $\ensuremath{\lambda}$ according to our formula ${\ensuremath{\lambda}}_{\mathrm{constraint}|\ensuremath{\xi}g1}\ensuremath{\approx}48N{\ensuremath{\xi}}^{2}{\ensuremath{\lambda}}_{\mathrm{constraint}|\ensuremath{\xi}=0}$. Non-minimal coupling may thus provide a relatively simple solution to the long-standing problem of excessive density perturbations in inflationary models.

CT in differential diagnosis of diffuse pleural disease.

Abstract: The CT features of benign and malignant pleural diseases have been described. However, the accuracy of these features in the differential diagnosis of diffuse pleural disease has not been assessed before. Without knowledge of clinical or pathologic data, we reviewed the CT findings in 74 consecutive patients with proved diffuse pleural disease (39 malignant and 35 benign). The patients included 53 men and 21 women 23-78 years old. Features that were helpful in distinguishing malignant from benign pleural disease were (1) circumferential pleural thickening, (2) nodular pleural thickening, (3) parietal pleural thickening greater than 1 cm, and (4) mediastinal pleural involvement. The specificities of these findings were 100%, 94%, 94%, and 88%, respectively. The sensitivities were 41%, 51%, 36%, and 56%, respectively. Twenty-eight of 39 malignant cases (sensitivity, 72%; specificity, 83%) were identified correctly by the presence of one or more of these criteria. Malignant mesothelioma (n = 11) could not be reliably differentiated from pleural metastases (n = 24). We conclude that CT is helpful in the differential diagnosis of diffuse pleural disease, particularly in differentiation of malignant from benign conditions.

General Equilibrium Pricing of Options on the Market Portfolio with Discontinuous Returns

Abstract: When the price process for a long-lived asset is of a mixed jump-diffusion type, pricing of options on that asset by arbitrage is not possible if trading is allowed only in the underlaying asset and a risk-less bond. Using a general equilibrium framework, we derive and analyze option prices when the underlying asset is the market portfolio with discontinuous returns. The premium for the risk of jumps and the diffusion risks forms a significant part of the prices of the options. In this economy, an attempted replication of call and put options by the Black-Scholes type of trading strategies may require substantial infusion of funds when jumps occur. We study the cost and risk implications of such dynamic hedging plans. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.

CD18-dependent and -independent mechanisms of neutrophil emigration in the pulmonary and systemic microcirculation of rabbits.

Abstract: Neutrophil (PMN) migration in the systemic and pulmonary circulation of rabbits was compared by using different inflammatory stimuli to determine the role of the leukocyte adhesion complex, CD11/CD18, in each of these vascular beds. The adhesion complex was blocked by administering the anti-CD18 mAb 60.3. The data show that mAb 60.3 blocks PMN emigration into inflammatory foci in the abdominal wall produced by implanting sponges containing either hydrochloric acid, Streptococcus pneumoniae, Escherichia coli endotoxin, or PMA. mAb 60.3 also inhibited PMN emigration in response to peritoneal instillation of S. pneumoniae. The effect of mAb 60.3 on PMN emigration in the lungs varied depending upon the stimulus. PMN failed to migrate into the PMA-induced pneumonia; however, mAb 60.3 pretreatment only partially inhibited endotoxin-induced pneumonia and did not inhibit S. pneumoniae or hydrochloric acid-induced pneumonias. PMN lavaged from the alveolar spaces in the Streptococcal pneumonia had similar quantities of mAb 60.3 bound to their surfaces as the circulating PMN. We conclude that the CD11/CD18 complex mediates PMN adherence in the systemic circulation. However, PMN adherence in the pulmonary circulation may occur by either CD18-dependent or -independent mechanisms that are specific to the inciting stimulus.