Showing papers by "University of Victoria published in 1994"
TL;DR: It is argued that to best comprehend many data sets, plotting judiciously selected sample statistics with associated confidence intervals can usefully supplement, or even replace, standard hypothesis-testing procedures.
Abstract: We argue that to best comprehend many data sets, plotting judiciously selected sample statistics with associated confidence intervals can usefully supplement, or even replace, standard hypothesis-testing procedures. We note that most social science statistics textbooks limit discussion of confidence intervals to their use in between-subject designs. Our central purpose in this article is to describe how to compute an analogous confidence interval that can be used in within-subject designs. This confidence interval rests on the reasoning that because between-subject variance typically plays no role in statistical analyses of within-subject designs, it can legitimately be ignored; hence, an appropriate confidence interval can be based on the standard within-subject error term-that is, on the variability due to the subject × condition interaction. Computation of such a confidence interval is simple and is embodied in Equation 2 on p. 482 of this article. This confidence interval has two useful properties. First, it is based on the same error term as is the corresponding analysis of variance, and hence leads to comparable conclusions. Second, it is related by a known factor (√2) to a confidence interval of the difference between sample means; accordingly, it can be used to infer the faith one can put in some pattern of sample means as a reflection of the underlying pattern of population means. These two properties correspond to analogous properties of the more widely used between-subject confidence interval.
2,432 citations
TL;DR: In this article, the authors define and discuss formalism and anti-formalism, individualism and holism, rationality and rule following, efficiency and reform, and complementarity.
Abstract: 1. Definitions and issues 2. Formalism and anti-formalism 3. Individualism and holism 4. Rationality and rule following 5. Evolution and design 6. Efficiency and reform 7. Conflicts and complementarities.
602 citations
TL;DR: The authors reviewed cognitive psychological research on the fallibility of human memory focusing on evidence of memory distortions and illusions, with the aim of sharing research on memory with clinical psychologists and practitioners who use memory recovery techniques to help clients recover suspected memories of childhood sexual abuse.
Abstract: Cognitive psychological research on the fallibility of human memory is reviewed, focusing on evidence of memory distortions and illusions, with the aim of sharing research on memory with clinical psychologists and practitioners who use memory recovery techniques to help clients recover suspected memories of childhood sexual abuse. The memory literature suggests that incautious use of memory recovery techniques may lead some adult clients who were not abused to come to believe that they were. Considerations relevant to assessing whether or not clients have repressed memories of childhood sexual abuse are discussed, as are suggestions for minimizing the risk of leading clients to create illusory memories or beliefs of childhood sexual abuse.
416 citations
TL;DR: In this article, the authors argue that imperfect competition in global markets creates a strategic interaction between governments that can lead to the inefficient distortion of pollution taxes, which can be decomposed into a rent capture effect and a pollution-shifting effect.
401 citations
TL;DR: The structure of proaerolysin determined by X-ray crystallography at 2.8 Å resolution is described and it is proposed that insertion of the protein into lipid bilayers to form ion channels is accounted for.
Abstract: Aerolysin is chiefly responsible for the pathogenicity of Aeromonas hydrophila, a bacterium associated with diarrhoeal diseases and deep wound infections. Like many other microbial toxins, the protein changes in a multistep process from a completely water-soluble form to produce a transmembrane channel that destroys sensitive cells by breaking their permeability barriers. Here we describe the structure of proaerolysin determined by X-ray crystallography at 2.8 A resolution. The protoxin (M(r) 52,000) adopts a novel protein fold. Images of an aerolysin oligomer derived from electron microscopy have assisted in constructing a model of the membrane channel and have led to the proposal of a scheme to account for insertion of the protein into lipid bilayers to form ion channels.
393 citations
TL;DR: The results show that color naming and word reading can operate independently to determine responses and indicate that the facilitating and interfering effects of automatic processes cannot be accurately measured in terms of differences from baseline.
Abstract: L.L. Jacoby's (1991) "process dissociation procedure" was used to quantitatively estimate the contributions of color-naming and word-reading processes to responding on the Stroop task. The results show that color naming and word reading can operate independently to determine responses. Degrading stimulus colors eliminated the typical asymmetry between Stroop facilitation and interference, as predicted by the equations (Experiments 1 and 2). Degrading stimulus colors reduced the estimated contribution of color naming to responding but had no effect on the estimated contribution of word reading (Experiment 2). In contrast, increasing the proportion of incongruent items reduced the estimated contribution of word reading but had no effect on the estimated contribution of color naming (Experiments 3 and 4). The results indicate that the facilitating and interfering effects of automatic processes cannot be accurately measured in terms of differences from baseline.
327 citations
TL;DR: A method of insertional mutagenesis for naturally transformable organisms has been adapted from Haemophilus influenzae and applied to the study of the pathogenesis of Campylobacter jejuni, which results in the same paralysed flagellar phenotype and the same invasion defects as the original mutants.
Abstract: A method of insertional mutagenesis for naturally transformable organisms has been adapted from Haemophilus influenzae and applied to the study of the pathogenesis of Campylobacter jejuni. A series of kanamycin-resistant insertional mutants of C. jejuni 81-176 has been generated and screened for loss of ability to invade INT407 cells. Eight noninvasive mutants were identified which showed 18-200-fold reductions in the level of invasion compared with the parent. Three of these eight show defects in motility, and five are fully motile. The three mutants with motility defects were further characterized to evaluate the method. One mutant, K2-32, which is non-adherent and non-invasive, has an insertion of the kanamycin-resistance cassette into the flaA flagellin gene and has greatly reduced motility and a truncated flagellar filament typical of flaA mutants. The adherent non-invasive mutants K2-37 and K2-55 are phenotypically paralysed, i.e. they have a full-length flagellar filament but are non-motile. All three mutants show an aberration in flagellar structure at the point at which the filament attaches to the cell. Mutants K2-37 and K2-55 represent overlapping deletions affecting the same gene, termed pflA (paralysed flagella). This gene encodes a predicted protein of 788 amino acid residues and a molecular weight of 90,977 with no significant homology to known proteins. Site-specific insertional mutants into this open reading frame result in the same paralysed flagellar phenotype and the same invasion defects as the original mutants. The differences in adherence between the two classes of flagellar mutant suggest that flagellin can serve as a secondary adhesion, although other adhesins mediate a motility-dependent internalization process. Characterization of the mutants at the molecular level and in animal models should further contribute to our understanding of the pathogenicity of these organisms.
290 citations
TL;DR: Algorithms that, for any tree T, compute vs ( T ) in linear time and compute an optimal layout with respect to vertex separation in time O ( n log n) are given.
Abstract: We relate two concepts in graph theory and algorithmic complexity, namely the search number and the vertex separation of a graph. Let s ( G ) denote the search number and vs ( G ) denote the vertex separation of a connected, undirected graph G . We show that vs ( G ) ≤ s ( G ) ≤ vs ( G ) + 2 and we give a simple transformation from G to G′ such that vs ( G′ ) = s ( G ). We characterize those trees having a given vertex separation and describe the smallest such trees. We also note that there exist trees for which the difference between search number and vertex separation is indeed 2. We give algorithms that, for any tree T , compute vs ( T ) in linear time and compute an optimal layout with respect to vertex separation in time O ( n log n ). Vertex separation has previously been related to progressive black / white pebble demand and has been shown to be identical to a variant of search number, node search number , and to path width , which has been related to gate matrix layout cost . All these properties are known to be computationally intractable. For fixed k , an O ( n log 2 n ) algorithm is known which decides whether a graph has path width at most k .
249 citations
TL;DR: Sea bream brains have three forms of GnRH, one of which is described herein and is called sea bream GnRH (sbGnRH), andylogenetic distribution of Gn RH peptides suggests sbGnRh arose in the perch-like fish as a gene duplication of the existing cGn RH-II or salmon GnRH genes.
Abstract: Most vertebrate species have more than one form of gonadotropin-releasing hormone (GnRH) in their brains, but it is not clear whether each form has a distinct function. We report that sea bream (Sparus aurata) brains have three forms of GnRH, one of which is described herein and is called sea bream GnRH (sbGnRH). The primary structures of two forms were determined by Edman degradation and mass spectral analysis. The amino acid sequence of sbGnRH is pGlu-His-Trp-Ser-Tyr-Gly-Leu-Ser-Pro-Gly-NH2. The second peptide is identical to a form originally isolated from chicken brains (cGnRH-II): pGlu-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly-NH2. cGnRH-II is the most ancient form of GnRH identified to date in jawed fish and the most prevalent form throughout the vertebrates. The third form of GnRH has previously been identified as salmon GnRH by cDNA studies and is confirmed here by chromatographic and immunological studies. Phylogenetic distribution of GnRH peptides suggests sbGnRH arose in the perch-like fish as a gene duplication of the existing cGnRH-II or salmon GnRH genes. All three identified GnRH peptides were synthesized and shown to release gonadotropin in vivo in the sea bream. The dominant form of GnRH stored in the pituitary was sbGnRH. Not only was the content of sbGnRH 500-fold greater than that of salmon GnRH but also cGnRH-II was not detected in the pituitary. The latter evidence suggests that sbGnRH is the endogenous releaser of gonadotropin II.
248 citations
TL;DR: The recent replacement of Atlantic mitochondrial lineages suggested by the data may be explained by severe reduction or extinction of northern Atlantic populations during the Pleistocene, followed by a recent reinvasion from the Pacific.
Abstract: Phylogenetic analyses of mitochondrial DNA (mtDNA) sequences were used to assess the matriarchal genetic structure of the threespine stickleback, Gasterosteus aculeatus. A 747 base-pair (bp) fragment of the cytochrome b was sequenced from 36 individuals collected from 25 localities in Europe, North America, and Japan. Two major divergent clades were revealed: one widespread in Japan but with representatives in some Alaskan and British Columbian lakes and the other common in Europe and North America. A simple diagnostic test using the polymerase chain reaction (PCR) and a restriction enzyme was used to assay additional individuals, confirming the absence of the Japanese clade in the Atlantic basin. Geographic distribution of mtDNA variation suggests (1) a recent origin of the Atlantic populations, and (2) support for previous hypotheses about the existence of Pleistocene refugia for freshwater fishes in Alaska and British Columbia. Silent substitution rates were used to date the colonization of the Atlantic at 90,000 to 260,000 yr before present, which conflicts with earlier dates implied by the fossil record. The recent replacement of Atlantic mitochondrial lineages suggested by our data may be explained by severe reduction or extinction of northern Atlantic populations during the Pleistocene, followed by a recent reinvasion from the Pacific. With a global perspective of the distribution of genetic variation as a framework, meaningful comparisons at a smaller geographical scale will now be possible.
244 citations
TL;DR: This article established a broad framework from which to interpret and evaluate the reading-science learning-writing connection, identifying current bottlenecks in thinking about, and highlighting productive inquiries into, print-based languages and scientific understanding.
Abstract: This article establishes a broad framework from which to interpret and evaluate the reading–science learning–writing connection. The presentation of breakthroughs, barriers, and promises is intended to outline the established links between, to identify current bottlenecks in thinking about, and to highlight productive inquiries into, print-based languages and scientific understanding. The ideas presented come from various disciplines connected to science education. The ideas are meant to be informative, provocative, integrative, supportive, and without hidden agenda.
TL;DR: In this article, the consequences of an avoidable risk of irreversible environmental catastrophe for society's optimal long-run consumption/pollution tradeoffs are considered, where the risk is assumed to be a non-decreasing function of pollution concentration which evolves as a dynamic environmental renewal process.
TL;DR: The authors examined the extent to which business students from Canada, Japan, Hong Kong, and Taiwan react differently to ethical dilemmas involving employees, supervisors, customers, suppliers, and business rivals.
Abstract: This study examines the extent to which business students from Canada, Japan, Hong Kong, and Taiwan react differently to ethical dilemmas involving employees, supervisors, customers, suppliers, and business rivals. The empirical results show that the national origin of the students does have an impact on their reactions to particular ethical dilemmas. In addition, the results indicate that controlling for the problem of social desirability response bias is important to ensure the validity of the empirical findings.
TL;DR: In this paper, an ocean general circulation model is used to examine the role of model geometry and surface buoyancy and wind stress forcing in the asymmetry of the global thermohaline circulation.
Abstract: An ocean general circulation model is used to examine the role of model geometry and surface buoyancy and wind stress forcing in the asymmetry of the global thermohaline circulation. The model domain is a highly idealized Atlantic and Pacific, linked by a circumpolar ocean in the south, and the integrations are performed under mixed boundary conditions diagnosed from spinups under various temperature and salinity profiles constructed from the present-day climatology. The model exhibits a tendency to favor either a “conveyor”-type circulation with sinking in the northern North Atlantic and upwelling in the North Pacific, or a “southern sinking” state with deep sinking in the Antarctic only. This bias is not dictated solely by the hydrological cycle, nor apparently by the greater northern extension of the Atlantic basin, but presumably by the overall asymmetry of the geometry. Equilibria with northern sinking in both basins can appear, however, when the winds in the Southern Ocean are reduced or th...
TL;DR: Comparison of the human and mouse TCRAC/TCRDC region with the previously reported mouse DNA sequence reveals homologous counterparts for the variable and joining (J) gene segments and both constant genes.
TL;DR: To determine the reliability of measures used in neuromuscular diagnosis and rehabilitation, 23 adults underwent identical testing on two occasions and Tibial nerve conduction velocity was highly reliable.
TL;DR: In this comparison, a very high level of organizational and noncoding sequence similarity is identified in contrast to previous findings in the β–globin gene cluster, which begins to question the notion that much of the chromosomal non–c coding sequence is junk.
Abstract: We report here the comparative DNA sequence analysis of nearly 100 kilobases of contiguous DNA in the C delta to C alpha region of the alpha/delta T cell receptor loci (TCRAC/TCRDC) of mouse and man. This analysis--the largest genomic sequence comparison so far--provides new insights into the functions of the T cell receptor genes as well as the surrounding chromosome structure through the identification of actively conserved DNA sequences. In this comparison we have identified a very high level of organizational and noncoding sequence similarity (approximately 71%) in contrast to previous findings in the beta-globin gene cluster. This observation begins to question the notion that much of the chromosomal non-coding sequence is junk.
TL;DR: The approach uses a scripting language that enables users to write their own routines for common reverse engineering activities, such as graph layout, metrics, and subsystem decomposition, thereby extending the capabilities of the reverse engineering toolset to better suit their needs.
Abstract: Program understanding can be enhanced using reverse engineering technologies. The understanding process is heavily dependent on both individuals and their specific cognitive abilities, and on the set of facilities provided by the program understanding environment. Unfortunately, most reverse engineering tools provide a fixed palette of extraction, selection, and organization techniques. This paper describes a programmable approach to reverse engineering. The approach uses a scripting language that enables users to write their own routines for common reverse engineering activities, such as graph layout, metrics, and subsystem decomposition, thereby extending the capabilities of the reverse engineering toolset to better suit their needs. A programmable environment supported by this approach subsumes existing reverse engineering systems by being able to simulate facets of each one.
TL;DR: In this article, a variable-domain beam finite element, whose number of elements is fixed, while the sizes of the elements change with time, is derived for axially moving materials.
TL;DR: The results suggest that the palliative treatment of advanced cancer and the terminally ill should be guided by a broad concept of well-being that goes beyond one based only on physical functioning.
Abstract: A cross-validation of the Karnofsky Performance Status (KPS) and quality of life (QOL) as measured by item 30 of the quality of life questionnaire developed by the European Organization for Research and Treatment of Cancer Study Group (EORTC QLQ-C30) was conducted using ordered logit analysis and prospective data from a continuous sample of 139 lung cancer patients. The QOL is found to be a much broader concept than the KPS, since it likely captures not only physical functioning but also functioning in the non-physical dimensions of social, emotional, and possibly cognitive well-being as well as the level of distress in the physical dimensions of pain, breathing and fatigue. These results suggest that the palliative treatment of advanced cancer and the terminally ill should be guided by a broad concept of well-being that goes beyond one based only on physical functioning.
TL;DR: Four experiments reported here provide evidence that (1) misleading postevent suggestions can impair memory for details in a witnessed event and (2) subjects sometimes remember sug-gested details as things seen in the event itself.
Abstract: The four experiments reported here provide evidence that (1) misleading postevent suggestions can impair memory for details in a witnessed event and (2) subjects sometimes remember sug-gested details as things seen in the event itself. All four experiments used recall tests in which subjects were warned of the possibility that the postevent information included misleading sug-gestions and were instructed to report both what they witnessed in the event and what was men-tioned in the postevent narrative. Recall of event details was poorer on misled items than on control items, and subjects sometimes misidentified the sources of their recollections. Our re-sults suggest that these findings are not due to guessing or response biases, but rather reflect genuine memory impairment and source monitoring confusions.
TL;DR: In this paper, the authors present simulations using an idealized global ocean model, which suggest that the North Atlantic ocean has three distinct circulation modes, each of which corresponds to a distinct climate state, and that adding a simple random component to the mean freshwater flux (which forces circulation) can induce rapid transitions between these three modes.
Abstract: RECENT data from the GRIP ice core1–3 in Greenland suggest that the climate of the last (Eemian) interglacial period was much less stable than that of the present interglacial. Rapid transitions between warm and cold periods were found to occur on timescales of just a few decades. The North Atlantic climate during the Eemian period was also shown to be characterized by three states, respectively warmer than, similar to and colder than today1,2. Recent data from the nearby GISP2 ice core have revealed some discrepancies with these findings, which remain to be resolved4,5. Here we present simulations using an idealized global ocean model, which suggest that the North Atlantic ocean has three distinct circulation modes, each of which corresponds to a distinct climate state. We find that adding a simple random component to the mean freshwater flux (which forces circulation) can induce rapid transitions between these three modes. We suggest that increased variability in the hydrological cycle associated with the warmer Eemian climate could have caused transition between these distinct modes in the North Atlantic circulation, which may in turn account for the apparent rapid variability of the Eemian climate.
TL;DR: In this paper, the authors prove global existence and uniqueness of classical solutions of Wigner-Poisson and Schrodinger-Schrodinger systems of equations for both repulsive and attractive potentials.
Abstract: We prove global existence and uniqueness of classical solutions of the Wigner–Poisson and Schrodinger–Poisson systems of equations for both repulsive and attractive potentials. In the repulsive case, we prove decay estimates for the particle density, the potential and the solutions.
01 Aug 1994-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the OPAL experiment at the CERN LEP collider recently upgraded its silicon strip micro-vertex detector from one coordinate readout (φ only) to two coordinate readouts ( φ and z).
Abstract: The OPAL experiment at the CERN LEP collider recently upgraded its silicon strip microvertex detector from one coordinate readout (φ only) to two coordinate readout (φ and z). This allows three dimensional vertex reconstruction and should improve lifetime measurements as well as b quark jet identification. This paper describes the new microvertex detector system with emphasis on the novel techniques and new components used to obtain the second coordinate information. These include the use of back-to-back single-sided detectors with orthogonally oriented readout strips, a gold printed circuit on a thin glass substrate to route the z strip signals to the electronics at the end of the detector, and the use of MX7 readout chips. Results on the performance of the new detector are presented.
TL;DR: The results reveal greater disability and somewhat greater use of personal assistance among women and differences between men and women in relationships between both personal and technical resources and subjective feelings of well-being across levels of functional disability.
Abstract: This study focused on gender differences in functional disability among older adults, their reliance on personal assistance and technical aids, and relationships among the use of these sources of assistance, functional disability, and subjective feelings of well-being. The analyses employ data from interviews conducted with 1,406 community-dwelling elders living in Manitoba, Canada. The results reveal (a) greater disability and somewhat greater use of personal assistance among women, and (b) differences between men and women in relationships between both personal and technical resources and subjective feelings of well-being across levels of functional disability.
TL;DR: Mutants of H. pylori and H. mustelae defective in hook production generated by allele replacement were non‐motile and devoid of flagellar filaments but produced both flageLLin subunits, which were localized in the soluble fraction of the cell, indicating that the regulation of flagescence expression in Helicobacter differs from that in the Enterobacteriaceae.
Abstract: Summary
Flagellar hooks were purified from Helicobacter pylori and Helicobacter mustelae. The 70 × 16nm H. pylori hook was composed of FIgE subunits of 78kDa, while the 72 × 16nm H. mustelae hook was composed of 87kDa subunits. N-terminal sequence was obtained for the FIgH proteins of both species, and for an internal H. mustelae FlgE peptide. Degenerate oligonucleotide primers allowed amplification of a 1.2 kb fragment from the H. mustelae chromosome, which carried part of the flgE gene. The corresponding H. pylori gene was cloned by immunoscreening of a genomic library constructed in λZAP Express, The translated H. pylori flgE sequence indicated a protein with limited homology with the hook proteins from Salmonella typhimurium and Treponema phagedenis. Mutants of H. pylori and H. mustelae defective in hook production generated by allele replacement were non-motile and devoid of flagellar filaments but produced both flagellin subunits, which were localized in the soluble fraction of the cell. The level of flagellin production was unchanged in the mutants, indicating that the regulation of flagellin expression in Helicobacter differs from that in the Enterobacteriaceae.
TL;DR: In this article, a new model for the aperture admittance of open-ended waveguide structures radiating into a homogeneous, lossy dielectric is presented, based on the physical and mathematical properties of the driving point admittance in passive, stable one-port networks.
Abstract: A new model for the aperture admittance of open-ended waveguide structures radiating into a homogeneous, lossy dielectric is presented. The model is based on the physical and mathematical properties of the driving point admittance of passive, stable one-port networks. The model parameters, which depend upon the geometry of the waveguide and aperture, are determined from a relatively small number of computed admittances. This computed data is obtained by a full-wave moment method solution and, hence, includes the effects of radiation and energy storage in the near field and the evanescent waveguide modes. The accuracy of the numerical method is demonstrated by comparison with measured values. As an example, the model parameters are determined for the coaxial-line geometry. The accuracy of the model, for both the direct and inverse problem, is verified and a rigorous sensitivity and uncertainty analysis is performed. The new model has important applications in the field of dielectric spectroscopy. >
TL;DR: Detailed gel electrophoresis analysis showed that the protein content of the H. pylori outer membrane is similar structurally to those of other species of Helicobacter but markedly different from those of taxonomically related Campylobacter spp.
Abstract: Despite the potential significance of surface-localized antigens in the colonization by and disease processes of Helicobacter pylori, few such components have been unequivocally identified and/or characterized. To further investigate the surface of this bacterium, monoclonal antibodies (MAbs) to a sarcosine-insoluble outer membrane fraction prepared from H. pylori NCTC 11637 were raised. MAbs were selected on the basis of their surface reactivity to whole cells by enzyme-linked immunosorbent assay, immunofluorescence, and immunoelectron microscopy. By use of this selection protocol, 14 surface-reactive MAbs were chosen. These MAbs were used to identify six protein antigens (molecular masses, 80, 60, 51, 50, 48, and 31 kDa), all of which were localized within or associated with the outer membrane. Two of the MAbs recognized the core region of lipopolysaccharide (LPS). Only these two anti-LPS MAbs also recognized the flagellar sheath, indicating a structural difference between the sheath and outer membrane. Three of the protein antigens (80, 60, and 51 kDa) were strain specific, while the other three antigens were present in other strains of H. pylori. Both the 51- and 48-kDa antigens were heat modifiable and likely are porins. A conserved 31-kDa protein may represent another species of porin. A method involving sucrose density ultracentrifugation and Triton extraction that allows the preparation of H. pylori outer membranes with minimal inner membrane contamination is described. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that the protein content of the H. pylori outer membrane is similar structurally to those of other species of Helicobacter but markedly different from those of taxonomically related Campylobacter spp. and Escherichia coli. H. pylori also appeared to lack peptidoglycan-associated proteins.