Showing papers by "McGill University published in 1987"

The short-form McGill pain questionnaire

Abstract: A short form of the McGill Pain Questionnaire (SF-MPQ) has been developed. The main component of the SF-MPQ consists of 15 descriptors (11 sensory; 4 affective) which are rated on an intensity scale as 0 = none, 1 = mild, 2 = moderate or 3 = severe. Three pain scores are derived from the sum of the intensity rank values of the words chosen for sensory, affective and total descriptors. The SF-MPQ also includes the Present Pain Intensity (PPI) index of the standard MPQ and a visual analogue scale (VAS). The SF-MPQ scores obtained from patients in post-surgical and obstetrical wards and physiotherapy and dental departments were compared to the scores obtained with the standard MPQ. The correlations were consistently high and significant. The SF-MPQ was also shown to be sufficiently sensitive to demonstrate differences due to treatment at statistical levels comparable to those obtained with the standard form. The SF-MPQ shows promise as a useful tool in situations in which the standard MPQ takes too long to administer, yet qualitative information is desired and the PPI and VAS are inadequate.

The Mindful Body: A Prolegomenon to Future Work in Medical Anthropology

Abstract: Conceptions of the body are central not only to substantive work in medical anthropology, but also to the philosophical underpinnings of the entire discipline of anthropology, where Western assumptions about the mind and body, the individual and society, affect both theoretical viewpoints and research paradigms. These same conceptions also influence ways in which health care is planned and delivered in Western societies. In this article we advocate the deconstruction of received concepts about the body and begin this process by examining three perspectives from which the body may be viewed: (1) as a phenomenally experienced individual body-self; (2) as a social body, a natural symbol for thinking about relationships among nature, society, and culture; and (3) as a body politic, an artifact of social and political control. After discussing ways in which anthropologists, other social scientists, and people from various cultures have conceptualized the body, we propose the study of emotions as an area of inquiry that holds promise for providing a new approach to the subject.

Equipoise and the ethics of clinical research.

Abstract: The ethics of clinical research requires equipoise--a state of genuine uncertainty on the part of the clinical investigator regarding the comparative therapeutic merits of each arm in a trial. Should the investigator discover that one treatment is of superior therapeutic merit, he or she is ethically obliged to offer that treatment. The current understanding of this requirement, which entails that the investigator have no "treatment preference" throughout the course of the trial, presents nearly insuperable obstacles to the ethical commencement or completion of a controlled trial and may also contribute to the termination of trials because of the failure to enroll enough patients. I suggest an alternative concept of equipoise, which would be based on present or imminent controversy in the clinical community over the preferred treatment. According to this concept of "clinical equipoise," the requirement is satisfied if there is genuine uncertainty within the expert medical community--not necessarily on the part of the individual investigator--about the preferred treatment.

Toward a Behavioral Theory of Charismatic Leadership in Organizational Settings

Abstract: Charismatic leadership has been largely overlooked by organizational theorists. In part, the problem can be attributed to the lack of a systematic conceptual framework Drawing from political science, sociology, and social psychology, this paper addresses the problem by proposing a model linking organizational contexts to charismatic leadership. A series of research hypotheses is offered.

Natural selection and the heritability of fitness components

Abstract: The hypothesis that traits closely associated with fitness will generally possess lower heritabilities than traits more loosely connected with fitness is tested using 1120 narrow sense heritability estimates for wild, outbred animal populations, collected from the published record. Our results indicate that life history traits generally possess lower heritabilities than morphological traits, and that the means, medians, and cumulative frequency distributions of behavioural and physiological traits are intermediate between life history and morphological traits. These findings are consistent with popular interpretations of Fisher's (1930, 1958) Fundamental Theorem of Natural Selection, and Falconer (1960, 1981), but also indicate that high heritabilities are maintained within natural populations even for traits believed to be under strong selection. It is also found that the heritability of morphological traits is significantly lower for ectotherms than it is for endotherms which may in part be a result of the strong correlation between life history and body size for many ectotherms.

Surface-Active Agents from Two Bacillus Species

Abstract: Two Bacillus species were studied which produced bioemulsifiers; however, they were distinctly different compounds. Bacillus sp. strain IAF 343 produced unusually high yields of extracellular biosurfactant when grown on a medium containing only water-soluble substrates. The yield of 1 g/liter was appreciably better than those of most of the biosurfactants reported previously. This neutral lipid product, unlike most lipid biosurfactants, had significant emulsifying properties. It did not appreciably lower the surface tension of water. On the same medium, Bacillus cereus IAF 346 produced a more conventional polysaccharide bioemulsifier, but it also produced a monoglyceride biosurfactant. The bioemulsifier contained substantial amounts of glucosamine and originated as part of the capsule layer. The monoglyceride lowered the surface tension of water to 28 mN/m. It formed a strong association with the polysaccharide, and it was necessary to use ultrafiltration to effect complete separation. The removal of the monoglyceride caused the polysaccharide to precipitate. It is suggested that earlier reports of biopolymers which both stabilized emulsions and lowered surface tension were actually similar aggregates of lipid and bioemulsifier.

Physical modeling and analysis of rain and clouds by anisotropic scaling multiplicative processes

Abstract: We argue that the basic properties of rain and cloud fields (particularly their scaling and intermittency) are best understood in terms of coupled (anisotropic and scaling) cascade processes. We show how such cascades provide a framework not only for theoretically and empirically investigating these fields, but also for constructing physically based stochastic models. This physical basis is provided by cascade scaling and intermittency, which is of broadly the same sort as that specified by the dynamical (nonlinear, partial differential) equations. Theoretically, we clarify the links between the divergence of high-order statistical moments, the multiple scaling and dimensions of the fields, and the multiplicative and anisotropic nature of the cascade processes themselves. We show how such fields can be modeled by fractional integration of the product of appropriate powers of conserved but highly intermittent fluxes. We also empirically test these ideas by exploiting high-resolution radar rain reflectivities. The divergence of moments is established by direct use of probability distributions, whereas the multiple scaling and dimensions required the development of new empirical techniques. The first of these estimates the "trace moments" of rain reflectivities, which are used to determine a moment-dependent exponent governing the variation of the various statistical moments with scale. This exponent function in turn is used to estimate the dimension function of the moments. A second technique called "functional box counting," is a generalization of a method first developed for investigating strange sets and permits the direct evaluation of another dimension function, this time associated with the increasingly intense regions. We further show how the different intensities are related to singularities of different orders in the field. This technique provides the basis for another new technique, called "elliptical dimensional sampling," which permits the elliptical dimension rain (describing its stratification) to be directly estimated: it yields del =2.22+0.07, which is less than that of an isotropic rain field (del =3), but significantly greater than that of a completely flat (stratified) two-dimensional field (de1-2).

The structural and environmental correlates of business strategy

Abstract: An attempt is made to relate several common dimensions of business-level strategy to their organizational contexts. A model is developed that predicts the structural and environmental correlates of a strategy on the basis of the number and uncertainty of its contingencies. It is shown that strategies of complex product innovation, marketing differentiation, market breadth and conservative cost control each have pronounced but very different relationships with bureaucratic and organic structural devices of uncertainty reduction, differentiation and integration, and with environmental dynamism, heterogeneity and hostility.

On the relationship between item response theory and factor analysis of discretized variables

Abstract: Equivalence of marginal likelihood of the two-parameter normal ogive model in item response theory (IRT) and factor analysis of dichotomized variables (FA) was formally proved. The basic result on the dichotomous variables was extended to multicategory cases, both ordered and unordered categorical data. Pair comparison data arising from multiple-judgment sampling were discussed as a special case of the unordered categorical data. A taxonomy of data for the IRT and FA models was also attempted.

Follicular Depletion During the Menopausal Transition: Evidence for Accelerated Loss and Ultimate Exhaustion*

Abstract: Although the menopause is generally considered to be the consequence of follicular exhaustion, the relationship between follicle number and the menopausal transition has not been explicity studied. We addressed this question in 17 women, aged 45-55 yr, who were undergoing elective total abdominal hysterectomy and salpingo-oophorectomy. The women were divided into 3 groups according to their menstrual history: 1) menstruating regularly (n = 6), 2) perimenopausal (irregular menses; n = 7), and 3) postmenopausal (greater than 1 yr since last menses; n = 4). The mean ages of the 3 groups were similar. Menstrual histories were confirmed by plasma hormone levels and endometrial histology. One ovary from each woman was serially sectioned for determination of follicle numbers. The mean number of primordial follicles in the ovaries of women who were still menstruating regularly was 10-fold higher than that in perimenopausal women [1392 +/- 355 (+/- SEM) vs. 142 +/- 72]. Follicles were virtually absent in the postmenopausal ovaries. Comparison of these data with those obtained by others in younger women suggests that follicular depletion accelerates dramatically in the last decade of menstrual life. These results support the view that declining follicular reserve is the immediate cause of both the perimenopausal and menopausal transitions, and indicate that the rate and, therefore, the regulation of follicular depletion change during the final phase of reproductive life.

Computation of system balancing transformations and other applications of simultaneous diagonalization algorithms

Abstract: An algorithm is presented in this paper for computing state-space balancing transformations directly from a state-space realization. The algorithm requires no "squaring up" or unnecessary matrix products. Various algorithmic aspects are discussed in detail. A key feature of the algorithm is the determination of a contragredient transformation through computing the singular value decomposition of a certain product of matrices without explicitly forming the product. Other contragredient transformation applications are also described. It is further shown that a similar approach may be taken, involving the generalized singular value decomposition, to the classical simultaneous diagonalization problem. These SVD-based simultaneous diagonalization algorithms provide a computational alternative to existing methods for solving certain classes of symmetric positive definite generalized eigenvalue problems.

Dissolved oxygen and fish behavior

Abstract: This essay reviews the behavioral responses of fish to reduced levels of dissolved oxygen from the perspective of optimization theory as used in contemporary behavioral ecology. A consideration of oxygen as a resource suggests that net oxygen gain per unit of energy expenditure will be the most useful currency for ecological models of breathing. In the process of oxygen uptake, fish always expend energy on perfusion, usually on ventilation and often on locomotion. These costs, and the risk of predation, will vary with oxygen availability and the type of behavioral response shown. The principal categories of behavioral response to reduced external availability of dissolved oxygen are (1) changes in activity, (2) increased use of air breathing, (3) increased use of aquatic surface respiration, and (4) vertical or horizontal habitat changes. Fish should choose whichever combination of responses minimizes the costs of meeting their oxygen demands. A small number of studies provides qualitative support for this prediction.

Happy and Sad TV Programs: How They Affect Reactions to Commercials

Abstract: Relative to a sad TV program, a happy program induced: (1) a happier mood as viewers watched both program and commercials, (2) greater perceived commercial effectiveness, (3) more affectively positive cognitive responses, and (4) to some extent, better recall. A main effect for commercial type was also noted, with emotional commercials leading to generally more positive reactions than informational commercials. A significant program-by-commercial interaction was obtained for the viewer's mood during the commercial, with the program effect greater for those viewing emotional commercials than for those viewing informational commercials.

Systematics of chlorite alteration at the Phelps Dodge massive sulfide deposit, Matagami, Quebec

Abstract: Hydrothermal alteration at the Phelps Dodge Archcan volcanogenic massive sulfide deposit has converted rhyodacite and rhyolite footwall rocks into the following mineral assemblages: quartz-chlorite-albite-epidote + or - sericite, quartz-chlorite + or - sericite, chlorite + or - sericite, and chlorite-talc + or - stilpnomelane. Alteration at constant Al was initiated by hydration, addition of Fe + Mg, silicification, and leaching of Ca + Na which produced Al-saturated chlorites with a wide range of Fe/Fe + Mg ratios within the assemblage quartz-chlorite-albite-epidote + or - sericite. With continued addition of Fe and less Mg, combined with extensive leaching of quartz, the chlorite became Al-undersaturated (quartz-chlorite-talc assemblage), and ultimately formed a rock composed essentially of chlorite. The chlorite-talc + or - stilpnomelane assemblage is stable in late crosscutting veinlets and in the ore zone.Chlorites in the Si-Al-Mg-Fe system form a rectangular solid solution plane with limited substitution of Al for Si and extensive substitution of Fe for Mg. In Si-Al space the solid solution plane is outlined by Al saturation (presence of other Al-rich mineral) and Al undersaturation (presence of Al-poor or Al-free mineral) boundaries. Al iv substitution for Si in the chlorites increases from 2.3 to 3.01 formula units (based on 8 Si + Al iv ) with Fe/Fe + Mg, whereas Al iv occupancy decreases from 2.88 to 2.65. The valence charge balance is compensated by octahedral site vacancies or by the conversion of Fe (super +2) to Fe (super +3) . The Al iv content of chlorite also increases with temperature. Chlorites on the Al-saturated boundary of the solid solution field form a potentially useful geothermometer: T degrees C = 106 Al iv + 18; Al iv is corrected for changes with the Fe/Fe + Mg ratio as: Al iv corrected = Al iv + 0.7 Fe/Fe + Mg.The Fe/Fe + Mg ratios of bulk rock and contained chlorite correlate well. Birefringence colors of the chlorite change from green to brown, violet, and Berlin Blue as Fe/Fe + Mg changes from 0.18 to 0.64. The Fe/Fe + Mg variation apparently depends largely on the proportions of Mg-rich seawater and Fe-rich hydrothermal fluid in the altering brine.

The role of androgen in the maintenance of sexual functioning in oophorectomized women.

Abstract: Five aspects of sexual behavior were monitored daily in three groups of women who had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy approximately 4 years ago for benign disease. One group had been receiving an estrogen-androgen preparation intramuscularly once a month since their surgery (E-A). The second group had been receiving estrogen alone (E) and the third group of women had remained untreated. Plasma estradiol and testosterone were measured at an established baseline and again on days 2, 4, 8, 15, 21, and 28 postinjection. Women who received both sex steroids reported higher rates of sexual desire (p less than 0.01), sexual arousal (p less than 0.01), and numbers of fantasies (p less than 0.01) than those who were either given E or who were untreated. Moreover, changes in these behaviors covaried with plasma testosterone but not with plasma estradiol levels during the treatment month as the drug was being metabolized. Rates of coitus and orgasm were also higher in the E-A group during the first two postinjection weeks (p less than 0.01) coincident with their higher testosterone levels. These findings imply that androgen may be critical for the maintenance of optimal levels of sexual functioning in postmenopausal women.

Theories of intergroup relations: International social psychological perspectives

Abstract: The Social Psychology of Intergroup Relations The Freudian Legacy of Intergroup Research Realistic Conflict Theory Social Identity Theory Equity Theory: Reconciling Affirmative Action Relative Deprivation Theory: Meeting the Challenge of Resource Mobilization Theory A Five-Stage Model of Intergroup Relations: Tokenism as a Potent Form of Discrimination Stereotypes, Attributions, and Discrimination Intergroup Contact: From Desegregation to Multiculturalism Toward an Integrated Theory of Intergroup Relations Bibliography Subject Index Author Index

Effects of eutrophication on reef-building corals. III: Reproduction of the reef-building coral Porites porites

Abstract: The sexual reproduction of Porites porites (Pallas), a shallow water hermatypic coral, was studied over a one-year period (June, 1982 to June, 1983) on three fringing reef complexes lying along an eutrophication gradient on the west coast of Barbados, West Indies. The data suggest that P. porites is a gonochoric species with a brooding mode of reproduction, but a low incidence (2.7%) of hermaphroditism was detected in a population sampled from a reef subjected to urban and industrial pollution. Gonadal development occurs within the mesenteries between the retractor muscles and the mesenterial filaments. Gametogenesis occurs during nine to ten months of the year, with the peak reproductive activity occurring predominantly in the fall and winter (November to January). Gametogenesis was therefore loosely synchronized between colonies; however, gonads in all stages of development were present within colonies throughout the reproductive season. The reproductive season of two P. porites populations sampled from two polluted reefs began one to two months earlier than that of a P. porites population sampled from a less polluted reef. The simultaneous presence of ova and larvae within a colony between November and April suggests that larvae may be released repeatedly during an extended breeding season. No correlation was found between the average number of gonads and polyp size. However, the gonad index (average number of gonads based on the sum of male and female gonads) showed an inverse relationship with a number of environmental variables. It is suggested that zooxanthellae in the maturing ova may play an important role in the reproductive success of P. porites. The reduction of zooxanthellae photosynthesis through reduced light levels may significantly lower the energy available from photosynthates to the maturing ova and/or embryos, thus depressing larval development and maturation. Coral colonies sampled from two polluted reefs contained lower numbers of larvae than colonies sampled from a less polluted reef. The 2: 1 sex ratio observed in a P. porites population sampled from a polluted reef may result from rapid asexual reproduction (fragmentation), indicating that the mode of reproduction may be influenced by environmental conditions.

Rate of mortality for elderly patients after fracture of the hip in the 1980's

Abstract: At an average follow-up of 2.1 years, we reviewed the records of 241 patients who had had a fracture of the hip. The average age of the patients was 75.4 years. The rate of mortality one year after the fracture was 21.6 per cent for the total group, 8.0 per cent for the low-risk group, and 49.4 per cent for the high-risk group. The standard mortality ratio was six times higher for the high-risk group than for the general population (individuals who did not have a fracture), matched for age. It was highest for patients who were less than seventy years old and lowest for those who were older than eighty. However, in the second year after the fracture, the standard mortality ratio approached unity--that is, the rate of mortality approached that of the general population. The results suggest that there is an inverse relationship between mortality and advanced age and that the impact of a fracture of the hip on mortality is seen primarily in the first year after injury.

Assessment of Fit in Overidentified Models with Latent Variables

Abstract: In recent years a number of measures have been suggested for the assessment of fit of overidentified models with latent variables (i.e., covariance structure models). This article discusses the logic of the fit problem, reviews the analytical intentions of six of these measures, with emphasis on their dependence on sample size, and compares the operational behavior of these measures in three-model situations: in a confirmatory factor model based on small N, and in two covariance structure models, one based on a slightly larger N and the other based on a large N. Given that these models and data are “typical,” results suggest that certain measures are both more stable across sample sizes and more sensitive to important variation in fit across substantively plausible models. The article concludes by suggesting a three-component approach to fitting: use of multiple measures, strategical overfitting, and comparison of parameter estimates in borderline versus more clearly sufficient models in terms of fit.

Immobile elements as monitors of mass transfer in hydrothermal alteration; Phelps Dodge massive sulfide deposit, Matagami, Quebec

Abstract: Hydrothermal alteration associated with an Archean stratiform volcanogenic massive sulfide deposit has converted aphyric rhyodacite to chloritite. In addition to normal chlorite components (MgO, FeO, Al 2 O 3 , SiO 2 ), the chloritite is enriched in TiO 2 , Zr, Y, and Nb. These elements and Al 2 O 3 are shown to be immobile using binary plots of analyses which produce linear arrays, with high correlation coefficients, that go through bulk composition and origin. Al 2 O 3 is the most immobile, followed by Zr, Nb, TiO 2 , and Y.Immobility requires that these elements became enriched by in situ residual concentration. This was caused mostly by initial wholesale leaching of silica--mainly quartz--followed by leaching of SiO 2 and Fe 2 O (super [whitesunwithrays]) 3 (total iron as Fe 2 O 3 ) from chlorite. Alteration of rhyodacite proceeded from an initial stage of silicification and chloritization (addition of MgO and Fe 2 O (super [whitesunwithrays]) 3 ) of glass and feldspar (loss of Na 2 O and CaO) to a stage of leaching of quartz wherein over 50 percent of the mass of the unit was lost. In the final stage, leaching of Fe 12 Si 8 O 20 (OH) 16 accounted for a further 10 percent loss, leaving Mg- and Al-rich chlorite as essentially the sole component of the chloritite rock.

Endstopped neurons in the visual cortex as a substrate for calculating curvature.

Abstract: Neurons in the visual cortex typically respond selectively to the orientation, and velocity and direction of movement, of moving-bar stimuli. These responses are generally thought to provide information about the orientation and position of lines and edges in the visual field. Some cells are also endstopped, that is selective for bars of specific lengths. Hubel and Wiesel first observed that endstopped hypercomplex cells could respond to curved stimuli and suggested they might be involved in detection of curvature, but the exact relationship between endstopping and curvature has never been determined. We present here a mathematical model relating endstopping to curvature in which the difference in response of two simple cells gives rise to endstopping and varies in proportion to curvature. We also provide physiological evidence that endstopped cells in area 17 of the cat visual cortex are selective for curvature, whereas non-endstopped cells are not, and that some are selective for the sign of curvature. The prevailing view of edge and curve determination is that orientations are selected locally by the class of simple cortical cells and then integrated to form global curves. We have developed a computational theory of orientation selection which shows that measurements of orientation obtained by simple cells are not sufficient because there will be strong, incorrect responses from cells whose receptive fields (RFs) span distinct curves (Fig. 1). If estimates of curvature are available, however, these inappropriate responses can be eliminated. Curvature provides the key to structuring the network that underlies our theory and distinguishes it from previous lateral inhibition schemes.

Proteoglycan-induced arthritis in BALB/c mice. Clinical features and histopathology.

Abstract: Immunization with chondroitinase ABC-digested fetal human cartilage proteoglycan and Freund's complete adjuvant induced polyarthritis and ankylosing spondylitis in female BALB/c mice. The initial external symptoms of the joint inflammation were swelling and redness. This was associated with edema of the synovium and periarticular tissues and gross proliferation of cells, which reached a peak during weeks 7-9 of the experiment. Mononuclear cell infiltration, with perivascular concentration and occlusion of small vessels, was common. Synovitis increased in severity, villous pannus developed, and erosions of bone, articular cartilage, and occasionally, growth plate were observed. The lumbar spine and the proximal intervertebral discs of the tail also exhibited inflammatory and degenerative changes. As the arthritis progressed, sometimes with acute inflammatory exacerbations, more joints became involved and, by the sixteenth to the twentieth weeks of the experiment, a progressive polyarthritis, with gross joint deformities and restricted function, developed in the majority of the limb joints. Clinical and morphologic features of the disease correlated well with radiologic analysis and with an increased deposition of 99mTc-methylene diphosphonate (determined by radionuclide imaging). The development of this arthritis was accompanied by the expression of cell-mediated and humoral immunity to the immunizing antigen. However, this immunity was also observed, although it was generally less well developed, in mice that received the intact or digested proteoglycan without adjuvant. These mice did not usually develop arthritis. Control mice that received only adjuvant did not develop arthritis.

Shear Strength of the Composite Bond to Etched Porcelain

Abstract: The shear bond strength of composite resin to porcelain was investigated to optimize variables for bonding porcelain laminate veneers. Scanning electron microscopy was initially used to examine the surface configuration of porcelain prepared under various conditions. A factorial experiment was undertaken to determine the effects of three different bonding methods on both etched and non-etched porcelain. Composite resin was bonded to the porcelain groups using (a) unfilled resin, (b) silane, and (c) silane with dentin adhesive. The results indicated a significant difference in shear bond strength for the three bonding groups, depending on the porcelain surface condition. For the unetched samples, significant differences in bond strength were obtained for all three bonding conditions. However, for the etched group, there were no differences between the silane and silane-with-dentin-adhesive groups. Porcelain etching significantly increased bond strength across all three bonding methods and was the main contributor to the obtained values.