Showing papers by "University of Toronto published in 1983"

Development and validation of a multidimensional eating disorder inventory for anorexia nervosa and bulimia.

Abstract: The development and validation of a new measure, the Eating Disorder Inventory (EDI) is described. The EDI is a 64 item, self-report, multiscale measure designed for the assessment of psychological and behavioral traits common in anorexia nervosa (AN) and bulimia. The EDI consists of eight sub-scales measuring: 1) Drive for Thinness, 2) Bulimia, 3) Body Dissatisfaction, 4) Ineffectiveness, 5) Perfectionism, 6) Interpersonal Distrust, 7) Interoceptive Awareness and 8) Maturity Fears. Reliability (internal consistency) is established for all subscales and several indices of validity are presented. First, AN patients (N = 113) are differentiated from female comparison (FC) subjects (N = 577) using a cross-validation procedure. Secondly, patient self-report subscale scores agree with clinician ratings of subscale traits. Thirdly, clinically recovered AN patients score similarly to FCs on all subscales. Finally, convergent and discriminate validity are established for subscales. The EDI was also administered to groups of normal weight bulimic women, obese, and normal weight but formerly obese women, as well as a male comparison group. Group differences are reported and the potential utility of the EDI is discussed.

Expression of recessive alleles by chromosomal mechanisms in retinoblastoma

Abstract: Inheritance of a mutation at the Rb-1 locus, which has been mapped to band q14 of human chromosome 13, results in predisposition to retinoblastoma. Cloned DNA segments homologous to arbitrary loci of human chromosome 13 and which reveal polymorphic restriction endonuclease recognition sequences, have been used to look for somatic genetic events that might occur during tumorigenesis. A comparison of constitutional and tumour genotypes from several cases indicates that tumorigenesis may result from the development of homozygosity for the mutant allele at the Rb-1 locus. The homozygosity in these cases results from mitotic nondisjunction, resulting in loss of the homologous wild-type chromosome, or from a mitotic recombination event.

Laser-induced periodic surface structure. I. Theory

Abstract: We develop a theory for laser-induced periodic surface structure by associating each Fourier component of induced structure with the corresponding Fourier component of inhomogeneous energy deposition just beneath the surface. We assume that surface roughness, confined to a region of height much less than the wavelength of light, is responsible for the symmetry breaking leading to this inhomogeneous deposition; we find strong peaks in this deposition in Fourier space, which leads to predictions of induced fringe patterns with spacing and orientation dependent on the angle of incidence and polarization of the damaging beam. The nature of the generated electromagnetic field structures and their relation to the simple "surface-scattered wave" model for periodic surface damage are discussed. Our calculation, which is for arbitrary angle of incidence and polarization, applies a new approach to the electrodynamics of randomly rough surfaces, introducing a variational principle to deal with the longitudinal fields responsible for local field, or "depolarization," corrections. For a $p$-polarized damaging beam our results depend on shape and filling factors of the surface roughness, but for $s$-polarized light they are essentially independent of these generally unknown parameters; thus an unambiguous comparison of our theory with experiment is possible.

Determination of surface tension and contact angle from the shapes of axisymmetric fluid interfaces

Abstract: A general, yet user-oriented scheme is provided to determine liquid—fluid interfacial tensions and contact angles from the shapes of axisymmetric menisci, i.e., from sessile as well as pendant drops. The strategy employed is to construct an objective function which expresses the error between the physically observed and a theoretical Laplacian curve, i.e., a curve representing a solution of the Laplace equation of capillarity. This objective function is minimized numerically using the method of incremental loading in conjunction with the Newton—Raphson method. This strategy is necessary as the otherwise powerful Newton-Raphson method depends on a good initial approximation to the true curve. Incremental loading provides a scheme of approaching the solution from a remote situation. A spherical meniscus, i.e., the case of infinite interfacial tension, is chosen here as the simple, unloaded solution. The method is set up from the point of view of user convenience: Apart from local gravity and densities of liquid and fluid phases the only input information required to determine the liquid-fluid interfacial tension is information on meniscus shape, typically several coordinate points in a coordinate system the origin of which may be placed at will. Specifically it is not necessary to identify the apex of the drop profile, the drop width, or drop height. For determinations of contact angles, the vertical coordinate of the three-phase line needs to be specified. As an illustration, “synthetic” drops, simulating physical drop profiles, are investigated. Sessile drops are generated with the aid of the tables of Bashforth and Adams and pendant drops with the aid of the tables of Fordham. The results show that the technique, which is an absolute one independent of any tables, is fully functional. A computer program implementing the method may be purchased from the authors.

Cell surface P-glycoprotein associated with multidrug resistance in mammalian cell lines.

Abstract: The plasma membranes of hamster, mouse, and human tumor cell lines that display multiple resistance to drugs were examined by gel electrophoresis and immunoblotting. In every case, increased expression of a 170,000-dalton surface antigen was found to be correlated with multidrug resistance. This membrane component is of identical molecular size and shares some immunogenic homology with the previously characterized P-glycoprotein of colchicine-resistant Chinese hamster ovary cells. This finding may have application to cancer therapy.

Individual Differences in Integrating Information between and within Sentences.

Abstract: Cette etude examine les differences individuelles dans la maniere dont les lecteurs integrent des mots successifs dans leur representation d'un texte. Elle met l'accent sur le role du travail mnemonique et sur son interaction avec les caracteristiques du texte a lire, etudiee par l'introduction de contradictions dans les elements du texte

Lithofacies types and vertical profile models; an alternative approach to the description and environmental interpretation of glacial diamict and diamictite sequences

Abstract: Increased knowledge of modern glacial depositional environments has resulted in rapidly evolving classifications of glacial tills. These are based to a large degree on theoretical considerations of likely depositional processes. The classifications are sophisticated and more advanced than the establishment of simple field criteria whereby individual till facies can be identified in Quaternary and Pre-Quaternary successions. This situation is compounded in many Quaternary terrains by the continued description of ‘tills’ in terms of laboratory-derived analytical data only, reflecting a traditional interest in stratigraphic correlation rather than reconstruction of depositional environment. Detailed sedimentological logging of lithofacies is rarely undertaken. There is thus considerable confusion as to what is being described or sampled when analytical data are presented for many Pleistocene ‘tills’. The same remarks apply to Pre-Pleistocene ‘tillites’. A lithofacies code is presented here for the rapid description and visual appraisal of field sequences or drill cores containing unconsolidated diamicts or lithified diamictites; the term‘till’is not used as it has a strict genetic definition referring to direct aggregation and deposition by glacier ice. Use of a four part code, in conjunction with codes already published for fluvial sediments, allows fundamental field properties to be depicted independent of genetic terminology and provides a firm basis for subsequent environmental interpretation and analytical work. The value of this approach is illustrated by comparing a representative suite of vertical profiles of diamict assemblages deposited by modern grounded glaciers with a classic late Pleistocene glacigenic sequence at Scarborough Bluffs, Ontario.

Formation in vitro of sperm pronuclei and mitotic chromosomes induced by amphibian ooplasmic components

Abstract: A cell-free preparation of the cytoplasm from activated eggs of Rana pipiens induces, in demembranated sperm nuclei of Xenopus laevis, formation of a nuclear envelope, chromatin decondensation, initiation of DNA synthesis, and chromosome condensation. Both soluble and particulate cytoplasmic constituents are required to initiate these processes in vitro. The observed changes resemble processes occurring during fertilization and the mitotic cycle in early amphibian embryos. Therefore, this cell-free system may be useful in biochemical analysis of the interactions of nucleus and cytoplasm that control nuclear behavior.

Laser-induced periodic surface structure. II. Experiments on Ge, Si, Al, and brass

Abstract: We report the results of a detailed investigation into the properties of the periodic damage structure that can be produced on nominally smooth surfaces of solids when they are irradiated with a single beam of intense laser radiation. The study is primarily concerned with extracting information from the Fourier transform of the damage structure as observed via the Fraunhofer diffraction pattern produced by reflecting a cw laser beam from the surface. In particular, the patterns produced in Ge, Si, Al, and brass by pulsed 1.06- and 0.53-\ensuremath{\mu}m radiation are compared as a function of the angle of incidence and polarization of the beam. We find that all materials contain similar and much more intricate detailed structure than has been previously appreciated. Whereas periodic ripple patterns oriented perpendicular to the polarization at near-normal incidence are commonly reported, the diffraction patterns reveal that in fact there exists a continuous distribution of periodic structure oriented at all angles with respect to the polarization. At near-normal incidence there are two dominant sets of "fringes" running perpendicular to the polarization, while for a $p$-polarized beam incident at g35\ifmmode^\circ\else\textdegree\fi{} there exist three dominant periodic structures; two which run perpendicular to the polarization and one which is oriented parallel to it. For $s$-polarized light incident at angles g35\ifmmode^\circ\else\textdegree\fi{} there are two dominant patterns which form a cross-hatched pattern with axes oriented at 45\ifmmode^\circ\else\textdegree\fi{} to the plane of incidence. A study of the evolution of the patterns on a shot-to-shot basis indicates that both the initial and laser-induced surface roughness play important roles in the evolution of the damage. We conclude with a comparison of our experimental results with those predicted by the theory developed in the preceding paper. Excellent agreement is found.

Marketing Theory with a Strategic Orientation

Abstract: The traditional paradigms of marketing are expanding to incorporate negotiated exchanges with internal and external coalitions in the pursuit of competitive advantage. This paper explores the impli...

Role of Antibody to S100 Protein in Diagnostic Pathology

Abstract: Normal tissues and various tumors were examined for S100 protein, using anti-S100 protein antiserum, in an immunoperoxidase reaction. Among normal tissues, in addition to the previously reported presence of S100 protein in some neurons, glial, and Schwann cells of the nervous system, melanocytes and Langerhans cells of the skin, interdigitating reticulum cells of lymph nodes, and chondrocytes, we demonstrated it in myoepithelial cells and ducts of sweat glands, salivary glands, and the breast, serous glands of the lung, fetal neuroblasts, and sustentacular cells of the adrenal medulla. Among neoplasms, S100 protein previously has been reported in neurogenic tumors, melanomas, and neuroblastomas; we have demonstrated it in mixed sweat gland tumors, histiocytosis X, pleomorphic adenomas of the salivary gland, medullary carcinomas of the breast, bronchioloalveolar carcinomas of the lung, sustentacular cells of pheochromocytomas, teratomas of the ovary, and tumors of cartilage (enchondromas, osteochondromas, and chondrosarcomas). With S100 protein producing tumors, a normal progenitor cell was identified, indicating that demonstration of S100 protein in tumors confirmed their origin.

Determinant Attributes in Retail Patronage: Seasonal, Temporal, Regional, and International Comparisons

Abstract: Determinants of retail patronage were identified and compared in a series of analyses of covariance of multinomial logit parameters. These parameters, estimated from random samples drawn from six N...

Private Security: Implications for Social Control

Abstract: Private security has become a pervasive feature of modern North American policing, both because of its rapid growth since 1960 and because it has invaded the traditional domain of the public police. Because this development has been viewed as an addendum to the criminal justice system, its significance for social control has not been recognized. This paper traces the development of private security in Canada and the United States since 1960, examines the reasons for its present pervasiveness, and explores its essential features: it is non-specialized, victim-oriented, and relies on organizational resources as sanctions. We conclude that private security is having a major impact on the nature of social control.

Crop mimicry in weeds

Abstract: The selective forces imposed by agricultural practices have resulted in the evolution of agricultural races of weeds or agroecotypes. Some agroecotypes are intimately associated with a specific crop. Such associations can involve a system of mimicry, whereby the weed resembles the crop at specific stages during its life history and, as a result of mistaken identity, evades eradication. Mimetic forms of weeds are most likely to be selected by handweeding of seedlings or by harvesting and seed cleaning procedures. A striking example of morphological and phenological resemblance is found in the cultivated rice mimic,Echinochloa crus-galli var.oryzicola, a native of Asian rice fields but now widely distributed in rice-growing areas of the world. Comparative studies of the growth, devel-opment and patterns of phenotypic variation of cultivated rice,E. crus-galli var.oryzicola andE. crus-galli var.crus-galli demonstrate that the crop mimic is more similar to rice in many attributes than it is to its close relative. It is proposed that intense handweeding practices in Asia constitute the main selective force favoring the evolution of rice mimicry inE. crus-galli var.oryzicola.

The site and function of the nasal valve.

Abstract: Previous observers have suggested that the main site of respiratory airflow resistance is localized to the vestibular region of the nose. This resistive segment of the airway was investigated using a "head-out" body plethysmograph in subjects with anatomically normal noses (a) untreated, (b) congested and (c) decongested. In all three conditions, 2/3 of the total nasal airflow resistance was found within the bony cavum in the vicinity of the pyriform aperture and about 1/3 in the cartilaginous vestibule. As might be expected, caval resistance changed proportionately with the degree of mucosal congestion; but, more surprisingly, vestibular resistance changed similarly. This was due in part to the observed forward expansion of the anterior ends of the inferior turbinates with congestion. EMG recordings in subjects breathing through both nostrils demonstrated a gradation of inspiratory alar dilator muscle activity with increased minute ventilation and with mucosal congestion, and there was no evidence of inspiratory alar collapse. But with elevated ventilation through one nostril only, or when the alar muscles were paralyzed by lidocaine block of the VIIth nerve, alar collapse occurred. These findings are of importance in the management of the congested but anatomically normal nose and in surgery of the nasal tip.

Variability in caffeine metabolism

Abstract: Urinary metabolites excreted after oral caffeine were quantified in a healthy sample (n = 68) from the Toronto population by HPLC analyses. The profile of metabolites, assessed by examining particular metabolite ratios, was found to differ widely among subjects. Ratios denoting cytochrome P-450-dependent activities were shown to be interethnically variable between oriental and Caucasian groups, whereas those indicative of xanthine oxidase activity exhibited neither significant interindividual variation nor an ethnic difference. It was also shown that a ratio providing an index of polymorphic N-acetyltransferase activity holds promise as a simple marker for acetylator status in man.

Methyl mercury exposure in northern quebec: ii. neurologic findings in children

Abstract: The relationship between prenatal exposure to methyl mercury and neurologic and developmental abnormalities was ascertained among 234 Cree Indian children aged 12 to 30 months from four northern Quebec communities. A pediatric neurologist, "blinded" to the children's level of exposure, assessed neurologic, physical, mental, and psychosocial development. Methyl mercury exposure was estimated from maternal hair segments representing the period of pregnancy. Abnormality of the tendon reflexes, observed in 13 boys (11 per cent) and in 14 girls (12 per cent), was positively associated with methyl mercury exposure only in boys and there was no consistent dose-response relationship. Other neurologic disorders were less prevalent and none was positively associated with exposure; indeed, incoordination was negatively associated with exposure in girls. The mild, isolated neurologic abnormalities found after prenatal exposure to methyl mercury in northern Quebec were different from the effects of prenatal exposure described in other areas, and their clinical importance can be determined only by continued medical surveillance.

Evidence from north-west Canada for an early Holocene Milankovitch thermal maximum

Abstract: According to the Milankovitch theory of global climatic change, maximum summer solar radiation at high latitudes of the Northern Hemisphere occurred at 10,000 yr BP (refs 1, 2). In particular, it predicts summer solstice radiation greater by 9–10%. Preliminary climate simulation experiments with these increased values of radiation confirm that high-latitude land surfaces received maximal insolation at ∼10,000 yr (refs 3, 4). Paradoxically, however, the large volume of fossil pollen and other evidence from North America indicates a maximum of Holocene warmth at 7,000–6,000 yr (ref. 5), and a recent review of the evidence from New England suggests that the warming began at 9,000 and ended at 5,000 yr, but also stresses the difficulties of interpretation in terms of climate change6. We summarize here data from sites in the north-west corner of mainland Canada (Fig. 1) that directly support the Milankovitch hypothesis.

Organization of the projections of a circumventricular organ: the area postrema in the rat

Abstract: The projections of the rat area postrema were analysed using anterograde and retrograde axonal transport techniques. Discrete injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the area postrema produced anterograde labeling in specific medullary and pontine nuclei. In the medulla, anterograde labeling was present in the internal solitary zone and dorsal division of the medial solitary nucleus, both of which also contained a small number of retrogradely labeled perikarya. Prominent projections to the dorsal motor nucleus of the vagus were seen only if the WGA-HRP injections in the area postrema invaded dorsal solitary nuclei. In the pons, anterograde labeling was present in the parabrachial nuclei, the dorsolateral tegmental nucleus, and the pericentral division of the dorsal tegmental nucleus. By far the major pontine projection was to the dorsolateral region of the middle one-third of the rostrocaudal extent of the parabrachial nuclei. Retrograde fluorescent tracing studies indicated that most area postrema neurons take part in this parabrachial projection. The area postrema projection to the parabrachial nuclei was bilaterally distributed, whereas that from the dorsal solitary nuclei was primarily ipsilateral. The external solitary zone, immediately subadjacent to the area postrema, neither received area postrema projections nor participated in the projections to the parabrachial nuclei. Fluorescent retrograde double labeling studies confirmed the bilateral nature of the area postrema projection to the parabrachial nuclei. In addition, because no doubly labeled neurons were observed it appears that individual area postrema neurons project to either side but not both sides of the dorsal pons. Thus, numerous neuronal pathways exist for the transfer of blood-borne information (that cannot cross the blood-brain barrier) from the area postrema to other brain regions.

The glycaemic index of foods tested in diabetic patients: A new basis for carbohydrate exchange favouring the use of legumes

Abstract: Recently diabetic patients have been encouraged to increase their carbohydrate intake, but exact details of which foods to use are lacking. To determine whether sufficiently large differences existed to justify more specific dietary advice, we compared the glycaemic responses to 50 g carbohydrate portions of different foods, taken as breakfast test meals by groups of five to seven diabetic patients. Two-to threefold differences were seen amongst the 15 foods tested. The glycaemic responses for spaghetti, ‘All-bran’, rice and beans were significantly below those for bread, while ‘Cornflakes’ were above. Factors predicted to influence this were without effect, including: substituting wholemeal for white bread, increasing substantially the simple sugars (using ‘All-bran’ or bananas instead of wholemeal bread) and doubling meal protein by adding cottage cheese to bread. Paired comparisons of the glycaemic response to the five legumes with those of the seven other starchy foods (breads, spaghetti, rice, Cornflakes, oatmeal porridge and potatoes) showed that the mean peak rise in blood glucose concentration and mean area under the glucose curve after beans were 23 and 28% lower, respectively, than the mean for the other foods (p < 0.001). Such results suggest a potentially valuable role for dried leguminous seeds in carbohydrate exchanges for individuals with impaired carbohydrate tolerance. These large differences in the blood glucose response to different food cannot at present be predicted directly from tables of chemical composition. Nevertheless, physiological testing may both aid in understanding the factors responsible and help selection of the appropriate carbohydrate foods for the diabetic diet.

Facile transition of poly[d(TG) x d(CA)] into a left-handed helix in physiological conditions.

Abstract: The DNA polymer d(GC)n . d(GC)n can undergo a transition from the usual right-handed 10.4 base pairs (bp) per turn B form to a novel left-handed 12 bp per turn Z form in response to altered environmental conditions. Several other alternating purine-pyrimidine DNA polymers with modified bases have been shown to undergo transitions from B to Z conformations, with varying degrees of difficulty. We report here that the unmodified DNA polymer d(TG)n . d(CA)n readily undergoes a transition to a Z conformation when subjected to unwinding torsional stress in ionic conditions that are close to physiological. By using a two-dimensional gel electrophoresis system, we have determined both the critical free energy of supercoiling that is required to initiate the transition and the free energy of supercoiling that is required to maintain this polymer in the Z form.

Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity

Abstract: Summary. A gravitationally self-consistent theory for relative sea-level variations forced by Pleistocene deglaciation events is employed to explore the extent to which RSL and free air gravity observations together constrain the viscosity of the mantle beneath the seismic discontinuity at 670 km depth. A trade-off is revealed between errors in the assumed deglaciation history and errors in the inferred value of the viscosity of the lower mantle. Taking full account of such uncertainty, plausible values of the viscosity beneath the transition region are bounded above by 1023 poise (cgs units). The preferred value is at least a factor of 2 lower than this and is strongly constrained by the observed free air gravity anomaly over Hudson Bay. The calculations described in detail here show for the first time that the relatively large gravity anomalies observed over sites of Wurm- Wisconsin deglaciation do not require any pronounced increase of mantle viscosity with depth in order to explain them.

qq qq ― system in a potential model

Abstract: We have examined the $\mathrm{qq}\stackrel{-}{\mathrm{qq}}$ system in a nonrelativistic potential model with color-dependent confinement forces and hyperfine interactions by solving the four-particle Schr\"odinger equation variationally. We find that normally the ground state of this system consists of two free mesons, but that exceptions to this rule probably occur for $K\overline{K}$ systems, where we find weakly bound ${0}^{++}$ states with a meson-meson structure reminiscent of the nucleon-nucleon structure of the deuteron. We show that these states may be identified with the ${S}^{*}$ and $\ensuremath{\delta}$ just below $K\overline{K}$ threshold. We further argue that the $\mathrm{qq}\stackrel{-}{\mathrm{qq}}$ system is not only nearly barren of bound states, but that it may not support any resonances. Finally, independent of their identification with observed states, we note that the $\mathrm{qq}\stackrel{-}{\mathrm{qq}}$ bound states are a model for the weak binding and color-singlet clustering observed in nuclei.

Descriptor Variable Systems and Optimal State Regulation

Abstract: Linear systems of the form E\dot{x} = Ax + Bu with E singular are treated. It is desired to find a control which drives the system asymptotically to the origin, minimizing a quadratic cost functional. No restrictions are placed on initial conditions. The cost associated with the impulsive behavior of the system is examined as well as existence and uniqueness of the optimal control. Through a sequence of coordinate transformations it is proven that the optimal control can be found by solving a reduced order Riccati equation.

Descriptor variable systems and optimal state regulation

Abstract: Linear systems of the form E\dot{x} = Ax + Bu with E singular are treated. It is desired to find a control which drives the system asymptotically to the origin, minimizing a quadratic cost functional. No restrictions are placed on initial conditions. The cost associated with the impulsive behavior of the system is examined as well as existence and uniqueness of the optimal control. Through a sequence of coordinate transformations it is proven that the optimal control can be found by solving a reduced order Riccati equation.