Showing papers by "University of British Columbia published in 1989"

Studies of the HER-2/neu proto-oncogene in human breast and ovarian cancer.

Abstract: Carcinoma of the breast and ovary account for one-third of all cancers occurring in women and together are responsible for approximately one-quarter of cancer-related deaths in females. The HER-2/neu proto-oncogene is amplified in 25 to 30 percent of human primary breast cancers and this alteration is associated with disease behavior. In this report, several similarities were found in the biology of HER-2/neu in breast and ovarian cancer, including a similar incidence of amplification, a direct correlation between amplification and over-expression, evidence of tumors in which overexpression occurs without amplification, and the association between gene alteration and clinical outcome. A comprehensive study of the gene and its products (RNA and protein) was simultaneously performed on a large number of both tumor types. This analysis identified several potential shortcomings of the various methods used to evaluate HER-2/neu in these diseases (Southern, Northern, and Western blots, and immunohistochemistry) and provided information regarding considerations that should be addressed when studying a gene or gene product in human tissue. The data presented further support the concept that the HER-2/neu gene may be involved in the pathogenesis of some human cancers.

Affect grid : A single-item scale of pleasure and arousal

Abstract: This article introduces a single-item scale, the Affect Grid, designed as a quick means of assessing affect along the dimensions of pleasure-displeasure and arousal-sleepiness. The Affect Grid is potentially suitable for any study that requires judgments about affect of either a descriptive or a subjective kind. The scale was shown to have adequate reliability, convergent validity, and discriminant validity in 4 studies in which college students used the Affect Grid to describe (a) their current mood, (b) the meaning of emotion-related words, and (c) the feelings conveyed by facial expressions. Other studies are cited to illustrate the potential uses of the Affect Grid as a measure of mood. In this article, we introduce the Affect Grid, a scale designed as a quick means of assessing affect along the dimensions of pleasure-displeasure and arousal-sleepiness. The Affect Grid is potentially suitable for any study that requires judgments about affect of either a descriptive or a subjective kind. The Affect Grid is a single-item scale. Our aim was for an instrument that would be short and easy to fill out and that could, therefore, be used rapidly and repeatedly. Currently available scales of affect are multiple-item checklists or questionnaires that are too time-consuming or too distracting for some purposes. In particular, they do not lend themselves to continuous or quickly repeated observation. They are awkward in dealing with the rapid fluctuations of affect that occur, for example, in response to music, or for all we know, to many everyday emotion-laden events. In repeated-meas ures designs, subjects tiring of the same checklist may eventually become less conscientious or, in longitudinal studies, drop out of the study. Researchers who have wanted something quick and simple have sometimes resorted to homespun measures—with resulting uncertainty as to precisely what is being measured and how well. The Affect Grid is shown in Figure 1. The subject is asked to take several minutes beforehand to learn precisely how to use it. General instructions for this purpose are given in the Appendix.1 Once the subject understands these general instructions, he or she can then be given the Affect Grid together with whatever specific instructions are appropriate, such as "Please rate

A Measure of Parenting Satisfaction and Efficacy

Abstract: We obtained normative information for the Parenting Sense of Competence (PSOC) scale from 297 mothers and 215 fathers of 4- to 9-year-old boys and girls. Principal-components analysis of the PSOC revealed two factors: Satisfaction, an affective dimension reflecting parenting frustration, anxiety, and motivation; and Efficacy, an instrumental dimension reflecting competence, problem-solving ability, and capability in the parenting role Significant inverse relationships were found between perceptions of child behavior problems and of parenting. For mothers, reported child behavior problems related to parenting satisfaction. For fathers, child behavior problems related both to satisfaction and efficacy as a parent. Mother and father reports of parenting were positively correlated; however, fathers obtained significantly higher scores than mother, particularly on the Satisfaction dimension. PSOC scores did not vary as a function of child age or sex.

Two-factor conceptualization of psychopathy: construct validity and assessment implications

Abstract: Two correlated factors have been identified in the Psychopathy Checklist (PCL), a valide and reliable instrument for the assessment of psychopathy in male prison populations. Factor 1 measures a selfish, remorseless, and exploitative use of others, and Factor 2 measures a chronically unstable and antisocial life-style. We examined the psychometric properties of the factor solutions and a variety of correlates of the two factors

Flexible Functional Forms and Global Curvature Conditions

Abstract: Empirically estimated flexible functional forms frequently fail to satisfy the appropriate theoretical curvature conditions. Lau and Gallant and Golub have worked out methods for imposing the appropriate curvature conditions locally, but those local techniques frequently fail to yield satisfactory results. We develop two methods for imposing curvature conditions globally in the context of cost function estimation. The first method adopts Lau's technique to a generalization of a functional form first proposed by McFadden. Using this Generalized McFadden functional form, it turns out that imposing the appropriate curvature conditions at one data point imposes the conditions globally. The second method adopts a technique used by McFadden and Barnett, which is based on the fact that a non-negative sum of concave functions will be concave. Our various suggested techniques are illustrated using the U.S. Manufacturing data utilized by Berndt and Khaled

The Mechanics of Airway Narrowing in Asthma

Abstract: This study was designed to determine the potential importance of airway wall thickening in the pathogenesis of the excess airways narrowing of asthma. The airways in postmortem specimens of lung obtained from 18 patients who suffered from asthma were compared to similar airways from 23 patients without asthma. Each airway was projected onto a digitizing board of a microcomputer to trace the internal and external perimeter of the airway and to calculate the submucosal and mucosal thicknesses. The relaxed length of the airway smooth muscle and the shortening required to occlude the airway lumen were calculated. These data show that the wall area was greater (p less than 0.001) in the membranous and cartilaginous airways of asthmatic patients and the airway smooth muscle shortening required to occlude the lumen was less in asthmatic than nonasthmatic airways (p less than 0.001). The increased wall area was due to increased areas of epithelium, muscle, and submucosa. We conclude that the walls of the airways of patients with asthma are thickened by chronic inflammation and that this thickening could be as important as smooth muscle shortening in determining the airway responsiveness of these patients.

Satellite-derived urban heat islands from three coastal cities and the utilization of such data in urban climatology

Abstract: NOAA AVHRR satellite infra-red data are used to display the surface radiant temperature heat islands of Vancouver, British Columbia, Seattle, Washington, and Los Angeles, California. Heat island intensities are largest in the day-time and in the warm season. Day-time intra-urban thermal patterns are strongly correlated with land-use; industrial areas are warmest and vegetated, riverine or coastal areas are coolest. Nocturnal heat island intensities and the correlation of the surface radiant temperature distribution with land use are less. This is the reverse of the known characteristics of near-surface air temperature heat islands. Several questions relating to the interpretation and limitations of satellite data in heat island analysis and urban climate modelling are addressed.

Writing expertise and second language proficiency

Abstract: The second-language writing performance of 23 young adults on three composition tasks was assessed in relation to their writing expertise and second-language proficiency. Both factors accounted for large proportions of variance in the qualities of written texts and problem-solving behaviors in the second language. But the factors exerted independent effects, suggesting they are psychologically distinct. Writing expertise proved to relate to: qualities of discourse organization and content in the compositions produced; attention to complex aspects of writing during decision making; problem-solving behaviors involving heuristic searches; and well-differentiated control strategies. Second-language proficiency proved to be an additive factor, enhancing the overall quality of writing produced, and interacting with the attention that participants devoted to aspects of their writing. But second-language proficiency did not visibly affect the processes of composing. In all analyses, more cognitively demanding argument and summary tasks produced significantly different behaviors from a less cognitively demanding letter task.

The evolution of sexual dimorphism in animals: Hypotheses and tests

Abstract: Three major hypotheses, based upon mechanisms of sexual selection, intersexual food competition and reproductive role division, have been advanced to explain the evolution of sexual dimorphism in body size and morphology of animals Genetic models suggest that all of the hypotheses are plausible, and empirical studies demonstrate that each of the three mechanisms operates in natural populations However, problems arise in testing hypotheses for the evolution of sexual dimorphism: more than one mechanism may be operating simultaneously, and the demonstrated occurrence of a mechanism does not indicate that it actually results in selection for dimorphism A recent statistical technique offers a solution to these problems and provides a promising new approach to the study of sexual dimorphism, in which researchers can assess the relative importance of each mechanism in present-day selection for sexual dimorphism within a species

Some errors in respirometry of aquatic breathers: How to avoid and correct for them

Abstract: Respirometry in closed and flow-through systems is described with the objective of pointing out problems and sources of errors involved and how to correct for them. Both closed respirometry applied to resting and active animals and intermillent-flow respirometry is described. In addition, flow-through or open respirometry is discussed, in particular when the system is in non-steady state. Simulations are used to show how improper analysis can lead to improper conclusions.

Small-scale deceit: deception as a marker of two-, three-, and four-year-olds' early theories of mind.

Abstract: This research report summarizes the results of a study into the abilities of 2-, 3-, and 4-year-old children to deceptively lead others into false beliefs, and is intended to help arbitrate a growing controversy as to when young persons first acquire some theory-like understanding of other minds. Utilizing a novel hide-and-seek board game as a context within which to observe children's spontaneous use of deceptive strategies, a total of 50 subjects between the ages of 2 1/2 and 5 were tested. In contrast to the competing findings of others, which are claimed to establish that children younger than approximately 4 suffer a cognitive deficit that wholly blocks them from the possibility of entertaining any sort of contrastive beliefs about beliefs, the results of this study show that even 2 1/2-year-olds are capable of already successfully employing a range of deceptive strategies that both trade upon an awareness of the possibility of false beliefs and presuppose some already operative theory of mind.

The micrometeorology of the urban forest

Abstract: Urban trees occupy a wide variety of habitats, from a single specimen competing in the urban jungle to extensive remnant or planted forest stands. Each is shown to produce distinct micro- to local scale climates contributing to the larger urban climate mosaic. These effects are discussed in relation to the radiative, aerodynamic, thermal and moisture properties of trees that so clearly set them apart from other urban materials and surfaces in terms of their exchanges of heat, mass and momentum with the atmosphere. Their resulting ability to produce shade, coolness, shelter, moisture and air filtration makes them flexible tools for environmental design.

Disequilibrium of Holocene sediment yield in glaciated British Columbia

Abstract: It is generally supposed that specific sediment yield—the quantity of sediment passing a monitored river cross-section per unit area drained upstream of that section—declines as the area drained increases1–3. Part of the sediment mobilized from the land surface is supposed to go back into storage at field edges, and on footslopes and floodplains. In contrast, we show here that data from British Columbian rivers reveal a pattern of increasing specific sediment yield at all spatial scales up to 3 × 104 km2. This results from the dominance of secondary remobilization of Quaternary sediments along river valleys over primary denudation of the land surface. The result controverts the conventional model which has been derived from studies of small, highly disturbed agricultural catch-ments. The rivers are still responding to the last glaciation, giving a landscape relaxation time greater than 10 kyr. This holds pro-found implications for geomorphological theory and for studies of erosion.

Reduction of a wave packet in quantum Brownian motion.

Abstract: The effect of the environment on a quantum system is studied on an exactly solvable model: a harmonic oscillator interacting with a one-dimensional massless scalar field. We show that in an open quantum system, dissipation can cause decorrelation on a time scale significantly shorter than the relaxation time which characterizes the approach of the system to thermodynamic equilibrium. In particular, we demonstrate that the density matrix decays rapidly toward a mixture of ``approximate eigenstates'' of the ``pointer observable,'' which commutes with the system-environment interaction Hamiltonian. This observable can be regarded as continuously, if inaccurately, monitored by the scalar field environment. Both because in a harmonic oscillator the state of the system rotates in the phase space and because the effective environment ``measurement'' is weak, the system, on the short ``collision'' time scale (1/\ensuremath{\Gamma}), maintains a coherence in this pointer observable on time scales of order [\ensuremath{\gamma}/\ensuremath{\Omega}ln(\ensuremath{\Gamma}/\ensuremath{\Omega}${)]}^{1/2}$ and on longer time scales settles into a mixture of coherent states with a dispersion approximately consistent with the vacuum state. The master equation satisfied by the exact solution differs from the other master equations derived both for the high-temperature limit and for T=0. We discuss these differences and study the transition region between the high- and low-temperature regimes. We also consider the behavior of the system in the short-time ``transient'' regime. For T=0, we find that, in the long-time limit, the system behaves as if it were subject to ``1/f noise.'' The generality of our model is considered and its predictions are compared with previous treatments of related problems. Some of the possible applications of the results to experimentally realizable situations are outlined. The significance of the environment-induced reduction of the wave packet for cosmological models is also briefly considered.

Conceptions of Personality Disorders and Dimensions of Personality

Abstract: Differing conceptions of personality disorders inherent in the Minnesota Multiphasic Personality Inventory Personality Disorder Scales and the Personality Adjective Checklist were evaluated within the context of the circuraplex model of interpersonal behavior and the 5-factor model of personality in a sample of 581 university students'. Conceptions of personality disorders were strongly and clearly related to dimensions of normal personality traits. Although the circumplex model illuminated conceptions of some of the disorders, the full 5-factor model was required to capture and clarify the entire range of personality disorders. Implications of these findings are discussed with reference to (a) personality disorders and personality traits and (b) suggestions for assessment of personality disorders.

Identification by ENDOR of Trp191 as the free-radical site in cytochrome c peroxidase compound ES

Abstract: The chemical identity of the amino acid free-radical site that represents one of the two oxidizing equivalents stored in the H2O2-oxidized intermediate (compound ES) of the mitochondrial heme enzyme, cytochrome c peroxidase (CcP) has been sought for almost a quarter of a century. Site-directed mutagenesis alone cannot yield this answer. Low-temperature 35-gigahertz (Q-band) electron nuclear double resonance (ENDOR) spectroscopy was used to examine compound ES prepared from proteins containing specifically deuterated methionine or tryptophan, as well as the amino acid replacement Trp51----Phe. The results definitely identify the site of the radical in compound ES as tryptophan, most likely Trp191.

Unimodular theory of canonical quantum gravity.

Abstract: Einstein's theory of gravity is reformulated so that the cosmological constant becomes an integration constant of the theory, rather than a "coupling" constant. However, in the Hamiltonian form of the theory, the Hamiltonian constraint is missing, while the usual momentum constraints are still present. Replacing the Hamiltonian constraint is a secondary constraint, which introduces the cosmological constant. The quantum version has a normal "Schr\"odinger" form of time development, and the wave function does not obey the usual "Wheeler-DeWitt" equation, making the interpretation of the theory much simpler. The small value of the cosmological constant in the Universe at present becomes a genuine question of initial conditions, rather than a question of why one of the coupling constants has a particular value. The key "weakness" of this formulation is that one must introduce a nondynamic background spacetime volume element.

A cross-cultural study of a circumplex model of affect.

Abstract: In the quest to understand how people conceptualize emotional feelings, one approach has been to seek the dimensions by which they perceive the similarities and differences among feelings. A circumplex model of affect represents this set of mutual relations by placing feeling-related concepts in a circular order in a space formed by two bipolar dimensions: pleasure-displeasure and arousalsleepiness. This article offers evidence that the circumplex structure, rather than being somehow dependent on the English-speaking student population in which it was originally obtained, occurs in different languages and cultures. In Study 1, Estonian, Greek, and Polish Ss judged the similarity between feelings described by 28 words in their respective native languages. In Study 2, Greek and Chinese Ss judged the similarity between feelings conveyed by 10 facial expressions. In all cases, multidimensional scaling of pairwise similarity scores yielded the circular order and underlying dimensions predicted by the circumplex.

Infant preference for both male and female infant-directed talk: a developmental study of attentional and affective responsiveness.

Abstract: This research increases our understanding of infants' preference for "motherese" by demonstrating that this preference extends to infant-directed talk (IDT) delivered by males as well as females and that infants show both more attentional responsiveness and more affective responsiveness to IDT than to adult-directed talk (ADT). Infants aged 4-5.5 and 7.5-9 months were shown video recordings of male and female adults reciting identical scripts in either IDT or ADT. Attentional preference was measured by the amount of time the infants watched in each condition, and affective responsiveness was measured by two trained raters. Overall, it was found that infants of both ages show greater attentional and affective responsiveness to IDT than to ADT when spoken by either a male or a female. The younger group was also found to be more responsive, on both measures, than the older group. Of perhaps greater significance, it was shown that the behaviour infants displayed in response to IDT makes them more attractive to naive adult judges. This suggests that IDT may facilitate and maintain positive adult-infant interactions.

A quantitative genetic model for growth, shape, reaction norms, and other infinite-dimensional characters

Abstract: Infinite-dimensional characters are those in which the phenotype of an individual is described by a function, rather than by a finite set of measurements. Examples include growth trajectories, morphological shapes, and norms of reaction. Methods are presented here that allow individual phenotypes, population means, and patterns of variance and covariance to be quantified for infinite-dimensional characters. A quantitative-genetic model is developed, and the recursion equation for the evolution of the population mean phenotype of an infinite-dimensional character is derived. The infinite-dimensional method offers three advantages over conventional finite-dimensional methods when applied to this kind of trait: (1) it describes the trait at all points rather than at a finite number of landmarks, (2) it eliminates errors in predicting the evolutionary response to selection made by conventional methods because they neglect the effects of selection on some parts of the trait, and (3) it estimates parameters of interest more efficiently.

Influence of Vesicle Size, Lipid Composition, and Drug-to-Lipid Ratio on the Biological Activity of Liposomal Doxorubicin in Mice

Abstract: The effects of vesicle size, lipid composition, and drug-to-lipid ratio on the biological activity of liposomal doxorubicin in mice have been investigated using a versatile procedure for encapsulating doxorubicin inside liposomes. In this procedure, vesicles exhibiting transmembrane pH gradients (acidic inside) were employed to achieve drug trapping efficiencies in excess of 98%. Drug-to-lipid ratios as high as 0.3:1 (wt:wt) could be obtained in a manner that is relatively independent of lipid composition and vesicle size. Egg phosphatidylcholine (EPC)/cholesterol (55:45; mol/mol) vesicles sized through filters with a 200-nm pore size and loaded employing transmembrane pH gradients to achieve a doxorubicin-to-lipid ratio of 0.3:1 (wt/wt) increased the LD50 of free drug by approximately twofold. Removing cholesterol or decreasing the drug-to-lipid ratio in EPC/cholesterol preparations led to significant decreases in the LD50 of liposomal doxorubicin whereas, the LD50 increased 4- to 6-fold when distearoylphosphatidylcholine was substituted for EPC. The results suggest that the stability of liposomally entrapped doxorubicin in the circulation is an important factor in the toxicity of this drug in liposomal form. In contrast, the antitumor activity of liposomal doxorubicin is not influenced dramatically by alterations in lipid composition. Liposomal doxorubicin preparations of EPC, EPC/cholesterol (55:45; mol:mol), EPC/egg phosphatidylglycerol (EPG)/cholesterol (27.5:27.5:45; mol:mol), and distearoylphosphatidylcholine/cholesterol (55:45; mol:mol) all demonstrated similar efficacy to that of free drug when given at doses of 20 mg/kg and below. Higher dose levels of the less toxic formulations could be administered, leading to enhanced increases in life span (ILS) values. Variations in vesicle size, however, strongly influenced the antitumor activity of liposomal doxorubicin. At a dose of 20 mg/kg, large EPC/cholesterol systems are significantly less effective than free drug (with ILS values of 65% and 145%, respectively). In contrast, small systems sized through filters with a 100-nm pore size are more effective than free drug, resulting in an ILS of 375% and a 30% long term (greater than 60 days) survival rate when administered at a dose of 20 mg/kg. Similar size-dependent effects are observed for distearoylphosphatidylcholine/cholesterol systems.