Showing papers by "University of Victoria published in 1993"

Childhood Sexual Abuse Long-Term Sequelae and Implications for Psychological Assessment

Abstract: This article examines the long-term sequelae of childhood sexual abuse in six areas: posttraumatic stress, cognitive distortions, altered emotionality, disturbed relatedness, avoidance, and impaired self-reference. It is concluded that childhood sexual abuse has a variety of long-term impacts and that the measurement strategies used to demonstrate these sequelae require further development.

A reverse‐engineering approach to subsystem structure identification

Abstract: Reverse-engineering is the process of extracting system abstractions and design information out of existing software systems. This process involves the identification of software artefacts in a particular subject system, the exploration of how these artefacts interact with one another, and their aggregation to form more abstract system representations that facilitate program understanding. This paper describes our approach to creating higher-level abstract representations of a subject system, which involves the identification of related components and dependencies, the construction of layered subsystem structures, and the computation of exact interfaces among subsystems. We show how top-down decompositions of a subject system can be (re)constructed via bottom-up subsystem composition. This process involves identifying groups of building blocks (e.g., variables, procedures, modules, and subsystems) using composition operations based on software engineering principles such as low coupling and high cohesion. The result is an architecture of layered subsystem structures. The structures are manipulated and recorded using the Rigi system, which consists of a distributed graph editor and a parsing system with a central repository. The editor provides graph filters and clustering operations to build and explore subsystem hierarchies interactively. The paper concludes with a detailed, step-by-step analysis of a 30-module software system using Rigi.

DNA sequence determination by hybridization: A strategy for efficient large-scale sequencing

Abstract: The concept of sequencing by hybridization (SBH) makes use of an array of all possible n-nucleotide oligomers (n-mers) to identify n-mers present in an unknown DNA sequence. Computational approaches can then be used to assemble the complete sequence. As a validation of this concept, the sequences of three DNA fragments, 343 base pairs in length, were determined with octamer oligonucleotides. Possible applications of SBH include physical mapping (ordering) of overlapping DNA clones, sequence checking, DNA fingerprinting comparisons of normal and disease-causing genes, and the identification of DNA fragments with particular sequence motifs in complementary DNA and genomic libraries. The SBH techniques may accelerate the mapping and sequencing phases of the human genome project.

The concepts and theories of modern democracy

Abstract: This highly acclaimed and popular academic text is now available in a new edition, having been revised and updated to cover the analyses of the use, abuse and ambiguity of many essential concepts used in political discourse and political studies These include basic concepts such as liberty, democracy, rights, representation, authority and political power New to this edition are three sections of great topical interest: entirely original analysis of global terrorism, which puts the recent developments of Islamic terrorism into perspective by comparing it with earlier examples of terrorist tactics by a variety of state agencies, revolutionary groups and minority nationalist movements extended discussion on multiculturalism, which supplements theoretical arguments with succinct summaries of the differing ways in which ethnic and cultural minorities have been dealt with in Canada, Britain, France and the Netherlands section on democratization that focuses on the problems, social and political and even theological, involved in turning authoritarian regimes into stable democracies in the Middle East and elsewhere Concepts and Theories of Modern Democracy is a stimulating guide to current world problems as well as essential reading for foundation courses at first or second year level such as elements of politics, political concepts and ideas and fundamentals in politics

Age Differences in Cognitive Performance in Later Life: Relationships to Self-Reported Health and Activity Life Style

Abstract: The predictive relationships among individual differences in self-reported physical health and activity life style and performance on an array of information processing and intellectual ability measures were examined. A sample of 484 men and women aged 55 to 86 years completed a battery of cognitive tasks measuring verbal processing time, working memory, vocabulary, verbal fluency, world knowledge, word recall, and text recall. Hierarchical regression was used to predict performance on these tasks from measures of self-reported physical health, alcohol and tobacco use, and level of participation in everyday activities. The results indicated: (a) individual differences in self-reported health and activity predicted performance on multiple cognitive measures; (b) self-reported health was more predictive of processing resource variables than knowledge-based abilities; (c) interaction effects indicated that participation in cognitively demanding activities was more highly related to performance on some measures for older adults than for middle-aged adults; and (d) age-related differences in performance on multiple measures were attenuated by partialing individual differences in self-reported health and activity.

Origin of Mammalian Gonadotropin-Releasing Hormones

Abstract: I. Introduction GONADOTROPIN-releasing hormone (GnRH) plays a pivotal role in reproduction. The existence of this neuropeptide, also called LHRH, was predicted in the 1950s (1), but the structure of the 10 amino acid peptide for porcine and ovine brains was not reported until the 1970s (2, 3). In the 20 yr since then, only one form of GnRH has been identified in most placental mammals, and this is still considered to be the sole neuropeptide causing the release of LH and FSH. The structure and functions of the mammalian form of GnRH have been reviewed a number of times (4s–8). Meanwhile, both mammalian GnRH and related forms of GnRH are now known to be present in primitive placental mammals, nonplacental mammals, and other vertebrates. Novel functions, in addition to the release of gonadotropins, exist. Studies of GnRH peptides and their genes have altered our views on the origin, function, and regulation of this neuropeptide.

Velocity structure of a gas hydrate reflector.

Abstract: Seismic reflection profiles across many continental margins have imaged bottom-simulating reflectors (BSRs) parallel to the seabed; these are often interpreted as the base of a zone in which methane hydrate "ice" is stable. Waveform inversion of seismic reflection data can be used to estimate from seismic data worldwide the velocity structure of a BSR and its thickness. A test of this method at a drill site of the Ocean Drilling Program predicts that sediment pores beneath the BSR contain free methane for approximately 30 meters. The hydrate and underlying gas represent a large global reservoir of methane, which may have economic importance and may influence global climate.

Response to the presence of a child with disabilities: parental stress and family functioning over time

Abstract: Parental stress and family functioning over time in families of children with disabilities was investigated. Comparisons were made between two time periods and with families of children who did not have disabilities; predictors of parental stress were identified. Results showed a high level of stability in parental stress and a modest degree of consistency over time in family functioning in families of children with disabilities. In these aspects, families of children with disabilities were not different from comparison families. There was also stability in the best predictors of parental stress (presence or absence of disabilities and the quality of family relationship). Of significant concern, families of children with disabilities were distinguished by the exceedingly greater amount of stress at both periods of study. Implications for family services and research were drawn.

Thin, aggregative fimbriae mediate binding of Salmonella enteritidis to fibronectin.

Abstract: The binding of human fibronectin and Congo red by an autoaggregative Salmonella enteritidis strain was found to be dependent on its ability to produce thin, aggregative fimbriae, named SEF 17 (for Salmonella enteritidis fimbriae with an apparent fimbrin molecular mass of 17 kDa). Two other fimbrial types produced by S. enteritidis, SEF 14 and SEF 21, were not responsible for the aggregative phenotype or for fibronectin binding. SEF 17-negative TnphoA mutants which retained the ability to produce SEF 14 and SEF 21 were unable to bind human fibronectin or Congo red and lost the ability to autoaggregate. Only purified SEF 17 but not purified SEF 14 or SEF 21 bound fibronectin in a solid-phase binding assay. Furthermore, only SEF 17 was able to inhibit fibronectin binding to S. enteritidis whole cells in a direct competition enzyme-linked immunosorbent assay. These results indicate that SEF 17 are the fimbriae responsible for binding fibronectin by this enteropathogen.

Evidence for the importance of bubbles in increasing air–sea gas flux

Abstract: Two models have been proposed to account for gas exchang between the atmosphere and the oceans: one involves direct transport of the gas through a surface boundary layer1; the other also includes a substantial enhancement of the gas flux due to bubbles formed by breaking waves2,3. In a long time-series of dissolved oxygen measurements, Wallace and Wirick4 observed sharply increased fluxes that seemed to be associated with wave activity. But the lack of vertical resolution meant that they could not rule out water advection and entrapment, rather than bubble-mediated air injection, as the cause of the increased flux. They were also unable to calculate transfer coefficients. Here we report simultaneous in situ observations from a vertical array of dissolved-gas sensors and a variety of other instruments during a single storm event. Our results confirm the importance of bubbles for the gas-transfer process. They also imply that existing transfer coefficients underestimate the transfer of weakly soluble gases during periods of bubble penetration.

Mediterranean Outflow Mixing and Dynamics

Abstract: The Mediterranean Sea produces a salty, dense outflow that is strongly modified by entrainment as it first begins to descend the continental slope in the eastern Gulf of Cadiz. The current accelerates to 1.3 meters per second, which raises the internal Froude number above 1, and is intensely turbulent through its full thickness. The outflow loses about half of its density anomaly and roughly doubles its volume transport as it entrains less saline North Atlantic Central water. Within 100 kilometers downstream, the current is turned by the Coriolis force until it flows nearly parallel to topography in a damped geostrophic balance. The mixed Mediterranean outflow continues westward, slowly descending the continental slope until it becomes neutrally buoyant in the thermocline where it becomes an important water mass.

Wisconsin card sorting test as a measure of frontal pathology: A review

Abstract: We reviewed studies of the Wisconsin Card Sorting Test (WCST) in which the test was administered to subjects with and without evidence of focal frontal-lobe dysfunction. This review indicated that few studies had investigated the differential performance of normals and those with frontal dysfunction. The evidence that frontal patients perform more poorly than nonfrontal patients is weak. There is insubstantial evidence to conclude that the WCST is a measure of dorsolateral-frontal dysfunction. The clinical utility of the test as a measure of frontal-lobe dysfunction is not supported nor is the use of the test as a marker of frontal dysfunction for research purposes.

A modified Massey-Omura parallel multiplier for a class of finite fields

Abstract: A Massey-Omura parallel multiplier of finite fields GF(2/sup m/) contains m identical blocks whose inputs are cyclically shifted versions of one another. It is shown that for fields GF(2/sup m/) generated by irreducible all one polynomials, a portion of the block is independent of the input cyclic shift; hence, the multiplier contains redundancy. By removing the redundancy, a modified parallel multiplier is presented which is modular and has a lower circuit complexity. >

Multi-way versus one-way constraints in user interfaces: experience with the DeltaBlue algorithm

Abstract: The efficient satisfaction of constraints is essential to the performance of constraint-based user interfaces. In the past, most constraint-based user interfaces have used one-way rather than multi-way constraints because of a widespread belief that one-way constraints were more efficient. In this paper we argue that many user interface construction problems are handled more naturally and elegantly by multi-way constraints than by one-way constraints. We present pseudocode for an incremental multi-way constraint satisfaction algorithm, DeltaBlue, and describe experience in using the algorithm in two user interface toolkits. Finally, we provide performance figures demonstrating that multi-way constraint solvers can be entirely competitive in performance with one-way constraint solvers.

A disease transmission model in a nonconstant population.

Abstract: A general SIRS disease transmission model is formulated under assumptions that the size of the population varies, the incidence rate is nonlinear, and the recovered (removed) class may also be directly reinfected. For a class of incidence functions it is shown that the model has no periodic solutions. By contrast, for a particular incidence function, a combination of analytical and numerical techniques are used to show that (for some parameters) periodic solutions can arise through homoclinic loops or saddle connections and disappear through Hopf bifurcations.

A family of stewart platforms with optimal dexterity

Abstract: Stewart platform configurations (architectures and poses) optimizing local dexterity are investigated. The condition number of the Jacobian matrix is used to quantify the dexterity of the manipulator. For a platform-centered Jacobian reference location and a given characteristic length for scaling purposes, a two-parameter family of optimal configurations is shown to exist. Two suitable architectural parameters defining the family are identified and properties of the optimal configurations are discussed. The optimization results are shown to be easily extended for other Jacobian reference locations and for other singular value-based local dexterity measures. It is suggested that the existence of a two-parameter family of optimal local configurations could be exploited to aid in the resolution of optimal architectures for global measures.

Recreational use, valuation, and management, of Killer Whales (Orcinus orca) on Canada's Pacific coast.

Abstract: The management of many ocean wildlife species is left in an institutional void, yet certain species command considerable public attention and have burgeoning management problems. In this paper the non-consumptive recreational use of Killer Whales (Orcinus orca) on Canada's Pacific Ocean coast is used as an example of management difficulties that are associated with oceanic species. Problems associated with jurisdiction and institutional arrangements are coupled to significant levels of biological uncertainty and restricted management options, as well as to management concerns associated with the human domain. The case is conceptualized as an interaction between the human and more general ecological spheres, mediated by the history of the relationship between humans and the species in question. Two routes to regulation are presented, dealing respectively with the human and ecological aspects. Of particular significance is the idea that both types of information are necessary to maximize utility to both the human user and the Whales.Results from an ongoing study of recreational use are presented to indicate some of the variables that have emerged. These are to be interpreted within current resource management infrastructure to create a tenuous situation. The unfortunate logic that results from this study is that if Killer Whales (a high-profile species) in Canada (a well-endowed nation) have not warranted more substantial protection, then the outlook for less well-known marine species in areas of the world where resource management priorities involve more direct survival concerns, is not optimistic.

Interannual Variability in Mediterranean Heat and Buoyancy Fluxes

Abstract: The flux of heat through the Strait of Gibraltar is known well enough that the Mediterranean Sea may be used as a climate test basin. After adjusting reported winds for changes in observing practice, the COADS for 1946 to 1988 was used together with standard heat flux formulas to estimate the long-term mean heat flux into the sea, giving 36 W mm2 more than is compatible with the Gibraltar exchange. As the estimated latent heat flux is consistent with the freshwater budget, it is suggested that standard formulas overestimate insulation in the Mediterranean. If a constant adjustment factor is used for the insulation, or for the latent heat loss, interannual variability of ±15 W m−2 is found in the total heat flux. Changes in the latent heat flux dominate, with contributions from both the humidity of the air and the saturation humidity at the temperature of the sea surface. The buoyancy flux from the sea is also examined and shows that the contributions from precipitation and runoff are import...

Two salmon neuropeptides encoded by one brain cDNA are structurally related to members of the glucagon superfamily

Abstract: A cDNA that codes for two peptides in the glucagon superfamily has been isolated from sockeye salmon brain. The first peptide is related to growth hormone-releasing hormone (GHRH), which has high sequence similarity with PACAP-related peptide. The second peptide is structurally related to vasoactive intestinal peptide, which is also related to a newly identified peptide in mannals, pituitary adenylate-cyclase-activating polypeptide (PACAP). The salmon precursor contains 173 amino acids and has dibasic and monobasic enzyme-processing sites for cleavage of a 45-amino-acid GHRH-like peptide with a free C-terminus and a 38-amino-acid PACAP with an amidated C-terminus. The salmon GHRH-like peptide has 40% amino acid sequence identity with the human GHRH and 56% identity with human PACAP-related peptide. The 38-amino-acid salmon PACAP is highly conserved (89–92% identity) with only three or four amino acid substitutions compared with the human, ovine and rat 38-amino-acid PACAP. Not previously reported for mammalian species, a short precursor coding for only one peptide exists in salmon in addition to the long precursor coding for two peptides. In the short precursor, the coding region for GHRH is deleted leaving the PACAP-coding region in a correct reading frame. This provides one possible control mechanism for an increased expression of one peptide (PACAP) without the concomitant increase in the other peptide (GHRH) as occurs in a double-peptide precursor. The importance of the 3′non-translated region of the salmon GHRH/PACAP precursor in the regulation of translation is suggested by its 70% nucleotide sequence identity to the 3′ non-translated region of the mammalian PACAP precursors. The structural organization of the salmon GHRH/PACAP precursor provides a possible evolutionary scheme for precursors that contain tandem peptides in the glucagon superfamily.

Characterization of three fimbrial genes, sefABC, of Salmonella enteritidis.

Abstract: Salmonella enteritidis produces thin, filamentous fimbriae designated SEF14. A 3.9-kb region of a 5.3-kb fragment encoding genes responsible for SEF14 biosynthesis was sequenced and found to contain three genes, sefABC. sefA encoded a novel fimbrin, the structural subunit of SEF14 fimbriae. sefB and sefC encoded proteins homologous to Escherichia coli and Klebsiella pneumoniae fimbrial periplasmic chaperone proteins and fimbrial outer membrane proteins, respectively, and are the first such genes to be characterized from Salmonella spp. in vitro expression directed by the 5.3-kb DNA fragment identified SefA, SefB, and SefC as approximately 14,000-, 28,000-, and 90,000-M(r) proteins, respectively, which correlated with their predicted amino acid sequences. sefB and sefC were not expressed in the absence of sefA. Primer extension analysis of sefABC revealed two major transcription start sites located upstream of sefA. Transcription of sefBC also initiated from the sefA promoter region. Secondary-structure analysis of the mRNA transcript for sefABC predicted the formation of two stable stem-loop structures in the intercistronic region between sefA and sefB indicative of differential regulation of SefA, SefB, and SefC translation. E. coli cells carrying the 5.3-kb DNA fragment of S. enteritidis DNA were unable to assemble distinguishable SEF14 fimbriae; however, immunogold-labelled SEF14 fimbriae were displayed on E. coli clones containing a 44-kb DNA fragment which encompassed the 5.3-kb region. Therefore, sefABC genes make up part of a complex sef operon responsible for the expression and assembly of SEF14 fimbriae.

Orographic precipitation, erosional unloading, and tectonic style

Abstract: Comparative tectonics of the Thelon (1.97 Ga) and Wopmay (1.88 Ga) orogens of north-west Canada and the Grenville (1.1 Ga) and Alleghany (0.3 Ga) orogens of eastern North America support geophysical models linking orographic precipitation and erosion to tectonic style. Paleomagnetic data imply that the Thelon and Grenville orogenic fronts were favorably situated to face trade winds and experience monsoonal precipitation. High rates of uplift could have been balanced by erosional unloading. Consequently, the orogenic fronts are deeply eroded and lack thin-skinned foreland thrust-and-fold belts. Tectonic progradation was achieved instead by thermal activation of the orogenic footwall. Foreland basins, where preserved, are overfilled with sediments that are dominantly fluvial to shallow marine, compositionally mature, and progradationally stacked. The Wopmay and Alleghany orogenic fronts developed in rain shadows. Erosional unloading could not offset even modest rates of tectonically driven uplift, resulting in mass flow onto the foreland manifested by thin-skinned thrust-and-fold belts and associated foreland basins. Foreland basins are underfilled and well preserved, containing sediments that are dominantly deep water, compositionally immature, and aggradationally stacked. The nature of the Mauritanide orogenic front is consistent with it being the windward complement of the Alleghany front.

DNA-based diagnostic tests for Salmonella species targeting agfA, the structural gene for thin, aggregative fimbriae.

Abstract: Salmonella enteritidis 27655-3b and a few diarrheagenic Escherichia coli strains produce morphologically and antigenically related, thin, aggregative fimbriae, collectively named GVVPQ fimbriae (S. K. Collinson, L. Emody, T. J. Trust, and W. W. Kay, J. Bacteriol. 174:4490-4495, 1992). To determine whether GVVPQ fimbriae are common to Salmonella spp. and other enteropathogenic members of the family Enterobacteriaceae, 113 isolates were phenotypically screened for Congo red binding and aggregative colony morphology. Presumptive positive and representative negative strains were examined by Western blotting (immunoblotting) by using antiserum to SEF 17, the native GVVPQ fimbria of S. enteritidis. Only four S. enteritidis strains and six E. coli isolates possessed substantial amounts of GVVPQ fimbriae after 24 h of incubation on T medium. Following 5 days of incubation, 56 of 93 Salmonella isolates (60%) and 1 of 7 additional E. coli clinical isolates possessed detectable levels of GVVPQ fimbriae. Since variable expression of GVVPQ fimbriae was observed among Salmonella isolates and some E. coli strains produced scant amounts, as revealed by immunoelectron microscopy, the ability to produce these fimbriae was evaluated by genotypic screening. The structural gene for the SEF 17 fimbrin, agfA, was amplified by the polymerase chain reaction, cloned, and sequenced to provide a characterized DNA probe. An agfA DNA fragment hybridized strongly to 603 of 604 (99.8%) Salmonella isolates but very weakly to 31 of 266 other members of the family Enterobacteriaceae including 26 of 137 E. coli strains, 3 of 14 Citrobacter spp., and single isolates of Shigella sonnei and Enterobacter cloacae. The agfA DNA probe proved to be a valuable diagnostic tool for Salmonella isolates arrayed on hydrophobic grid membrane filters. Unique agfA sequences were targeted in the development of a polymerase chain reaction assay specific for Salmonella spp. Images