Showing papers by "University of Victoria published in 1987"
TL;DR: Experimental results reported here indicate that the Markov modelling approach generally achieves much better data compression than that observed with competing methods on typical computer data.
Abstract: A method of dynamically constructing Markov chain models that describe the characteristics of binary messages is developed. Such models can be used to predict future message characters and can therefore be used as a basis for data compression. To this end, the Markov modelling technique is combined with Guazzo's arithmetic coding scheme to produce a powerful method of data compression. The method has the advantage of being adaptive: messages may be encoded or decoded with just a single pass through the data. Experimental results reported here indicate that the Markov modelling approach generally achieves much better data compression than that observed with competing methods on typical computer data.
255 citations
TL;DR: The model was successfully tested by demonstrating that oligomers with sequences quite different from the replicase initiator were able to bind coat protein, suggesting that while the hairpin loop structure is essential for protein binding, the base-paired residues do not contact the protein directly.
Abstract: The specific interaction between R17 coat protein and its target of translational repression at the initiation site of the R17 replicase gene was studied by synthesizing variants of the RNA binding site and measuring their affinity to the coat protein by using a nitrocellulose filter binding assay. Substitution of two of the seven single-stranded residues by other nucleotides greatly reduced the Ka, indicating that they are essential for the RNA-protein interaction. In contrast, three other single-stranded residues can be substituted without altering the Ka. When several of the base-paired residues in the binding site are altered in such a way that pairing is maintained, little change in Ka is observed. However, when the base pairs are disrupted, coat protein does not bind. These data suggest that while the hairpin loop structure is essential for protein binding, the base-paired residues do not contact the protein directly. On the basis of these and previous data, a model for the structural requirements of the R17 coat protein binding site is proposed. The model was successfully tested by demonstrating that oligomers with sequences quite different from the replicase initiator were able to bind coat protein.
184 citations
TL;DR: In this paper, a search for B0↔B¯0 oscillations (mixing) using events with two identified muons from data collected at the CERN p¯p collider is reported.
165 citations
TL;DR: The productive narrative competence of three young children as revealed in their spontaneously occurring conversations recorded over an 18-month period during their kindergarten and grade one years was investigated.
Abstract: The productive narrative competence of three young children as revealed in their spontaneously occurring conversations recorded over an 18-month period during their kindergarten and grade one years was investigated. Almost 90 hours of the children's conversations, produced as they were being driven to and from school, were audiotaped and analysed in order to determine whether children between the ages of five and seven include narrative accounts in their conversations with each other and, if so, the nature of the narrative language produced. The subjects were found routinely and regularly to produce a striking variety of narrative forms; 14 different narrative types were distinguished and defined, six of which have not previously been reported in the literature on children's narratives. Seventy per cent of the recorded narratives took anecdotal form; original fantasy narratives occurred only rarely. A significant proportion of the narratives were collaboratively created.
152 citations
TL;DR: This paper argued that the philosophical dilemmas posed by the concern with change and the claim to political realism are intimately related, and argued that political realism should be understood less as a coherent theoretical position in its own right than as the site of a great many interesting claims and metaphysical disputes.
Abstract: Much recent commentary on the theory of international politics has focused on the analysis of change and the continuing vitality of political realism. This paper argues that the philosophical dilemmas posed by the concern with change and by the claim to political realism are intimately related. The argument is pursued in the context of contrasting traditions of political realism, of the antithesis between structuralism and historicism in contemporary social and political theory, and of recent tendencies and controversies in the literature on neorealist theories of international politics. The paper concludes that political realism ought to be understood less as a coherent theoretical position in its own right than as the site of a great many interesting claims and metaphysical disputes. As there is no single tradition of political realism, but rather a knot of historically constituted tensions and contradictions, these tensions and contradictions might be reconstituted in a more critical and creative manner. This involves an examination of the way the core categories of international political theory depend upon a particular formulation of the relationship between identity and difference—a formulation which must be refused.
136 citations
TL;DR: In this paper, a theoretical model of the evolution of the peripheral tourism industry is used to discover whether an ideal strategy exists which could avoid a "centre-periphery conflict" in Canada's Northwest Territories.
118 citations
TL;DR: In this article, the authors report evidence for beauty particle production through the observation of dimuon events from proton-antiproton collisions at energies of √ s=546 GeV and √s=630 GeV at the CERN collider.
111 citations
TL;DR: Development of the nervous system of the pluteus larva of Strongylocentrotus droebachiensis was investigated using indirect immunofluorescence with antibodies against dopamine, GABA, and serotonin, and glyoxylic acid-induced fluorescence of catecholamines.
Abstract: Development of the nervous system of the pluteus larva of Strongylocentrotus droebachiensis was investigated using indirect immunofluorescence with antibodies against dopamine, GABA, and serotonin, and glyoxylic acid-induced fluorescence of catecholamines. Serotonergic cells first appear in full gastrulae; dopaminergic and GABAergic cells are present in early four-arm plutei. The number of neurons and the complexity of the nervous system increases through development of the pluteus. In the pluteus the dopaminergic component of the nervous system includes a ganglion in the lower lip of the mouth and a pair of ganglia at the base of the post-oral arms which extend axons along the base of the circumoral ciliary band. The distribution of cells visualized by glyoxylic acid-induced fluorescence is similar to that of dopaminergic cells. GABAergic neurons occur in the upper lip and in the wall of the esophagus. Serotonergic neurons are present in the lower lip; the pre-oral hood contains an apical ganglion which extends axons along the base of the epidermis overlying the blastocoel. The dopaminergic and GABAergic components of the nervous system are associated with effectors involved in feeding and swimming. The serotonergic component is not associated with any apparent effectors but may have a role in metamorphosis.
110 citations
TL;DR: In this article, the Roman Slave supply and slave breeding were discussed. But the focus was on the Roman slave supply and not the slave breeding process, and not on the slaves themselves.
Abstract: (1987). On the Roman Slave supply and Slavebreeding. Slavery & Abolition: Vol. 8, Classical Slavery, pp. 42-64.
107 citations
TL;DR: Cells producing either of the flagellum antigenic types serotyped as LIO 8 do not carry the serological determinants for this serogroup, indicating that flagella composed of the Mr 61,500 flageLLin do notcarry the serology determinants.
Abstract: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of flagella dissociated from strains of Campylobacter coli and Campylobacter jejuni belonging to the heat-labile serogroup LIO 8 showed that some strains were capable of producing flagellin subunits of two different molecular weights (MrS), 59,500 and 61,500. Immunoelectron microscopy of cultures of the type strain of this serogroup, C. coli VC167, showed the presence of two flagellum filaments of different antigenic specificity. Epitopes on the surface of one of these flagella bound antibodies in LIO 8 typing antiserum, and Western blotting (immunoblotting) and immunoprecipitation showed that the flagellum was composed of flagellin of Mr 61,500. The other flagellum antigenic type did not bind LIO 8 antibodies but did possess serospecific epitopes which bound a second polyclonal antiserum, LAH2. This second antigenic flagellum type was composed of the Mr 59,500 flagellin. Cells producing either of the flagellum antigenic types serotyped as LIO 8, indicating that flagella composed of the Mr 61,500 flagellin do not carry the serological determinants for this serogroup. The ability of C. coli VC167 to produce these flagella of different subunit MrS was shown to represent a bidirectional antigenic variation. When measured in culture medium, the phase 1-to-phase 2 transition occurred at a rate of approximately 2.0 x 10(-5) per cell per generation, and the phase 2-to-phase 1 transition occurred at a rate of 1.2 x 10(-6) per cell per generation.
98 citations
TL;DR: The attitudes of two samples of adolescents (total N = 2,105) from Victoria, British Columbia, and Shanghai, People's Republic of China, toward computer studies and selected school subjects were surveyed and compared as discussed by the authors.
Abstract: The attitudes of two samples of adolescents (total N = 2,105) from Victoria, British Columbia, and Shanghai, People’s Republic of China, toward computer studies and selected school subjects were surveyed and compared. The Chinese students were significantly more positive in their attitudes toward computers, science, and writing than were the British Columbia students. In addition, the students from Shanghai displayed fewer sex or age differences among themselves, except when asked to give opinions about the competence of females with regard to computer use and science. Both samples of females agreed that women have as much ability as men in these areas, whereas males in both countries were significantly more skeptical. The study also supports the validity and reliability of attitude research in a cross-cultural context.
TL;DR: In this paper, the real space of all real symmetric or complex self-adjoint matrices is characterized for adjoint-preserving maps on all n × n matrices.
TL;DR: Epileptic patients whose speech dominance had been ascertained using the carotid amytal technique were given a verbal dichotic listening test and showed a REA, while patients with right hemisphere speech representation tended not to show a bias toward either ear.
TL;DR: In this paper, the photino is assumed to be the lightest supersymmetric particle and that it is massless, and the authors find a limit on the squark mass of m q >45 GeV /c 2 at 90% CL.
TL;DR: The results indicate that A. victoria is most important as a predator of herring larvae during a short period after the larvae hatch, and unfed larvae were more vulnerable to jellyfish predation than fed larvae of the same age.
Abstract: Gut-content analysis of Aequorea victoria collected in Kulleet Bay, Vancouver Island, British Columbia, Canada, in 1983, showed that the jellyfish consumed herring (Clupea harengus pallasi) larvae, primarily yolksac [≦8mm notochord length (NL)] and post-yolksac larvae (≦12mm NL). Behavioral experiments with laboratory-reared larvae showed that the ability to escape after contact with a jellyfish tentacle increased dramatically from yolksac through pre-metamorphic larvae (up to 20 mm NL). Early yolksac larvae were captured in 91% of the contacts with a tentacle, but the largest larvae in only 13%. Unfed larvae were more vulnerable to jellyfish predation than fed larvae of the same age. Our results indicate that A. victoria is most important as a predator of herring larvae during a short period after the larvae hatch.
TL;DR: In this paper, a machine language subroutine is described that can provide 1-msec accuracy for the BASIC TIMER function, which can result in interval timing errors as great as 110 msec.
Abstract: Many types of behavioral research require the determination of elapsed time, for example to establish interstimulus intervals and to measure reaction time. The use of an IBM PC for on-line control of such applications is limited by the poor timing resolution ordinarily available. The IBM BIOS time information that is used for the BASIC TIMER function can result in interval timing errors as great as 110 msec. A machine language subroutine is described that can provide 1-msec accuracy. A BASIC program is also described that employs this subroutine to measure auditory reaction time.
TL;DR: The gonadotropin-releasing hormones are a family of peptides that play a pivotal role in reproduction and their phylogenetic story includes diversification to novel uses of GnRH and multiple molecular forms in single species.
TL;DR: The analyses indicated that there are at least two higher-order factors in the MIA, and that the two factor solution has potential for resolving conflicting results in the literature regarding age differences in both metamemory and metAMemory/memory performance relationships.
Abstract: This study was designed to test the hypothesis that there are multiple factors of metamemory present in the Metamemory in Adulthood (MIA) questionnaire. Data on seven MIA scales from six separate studies on memory/metamemory relationships (total N = 750) were combined to yield two half-samples for cross-validation purposes. The samples were partitioned into young, middle-aged, and old groups. A multiple group confirmatory factor analysis was then conducted on the data, using the first half sample to develop a model and the second half sample to validate it. Although the models did not fully cross-validate, both analyses indicated that there are at least two higher-order factors in the MIA. The first involves beliefs about self-efficacy in using memory. The second factor combines knowledge about memory and affect concerning memory (e.g., achievement motivation). The analyses also indicated that the factor loadings for the second factor, tentatively labelled Knowledge, were invariant across the three age groups, but that there were age differences in the Self-Efficacy Beliefs factor loadings. The differences were localized to age-related increases in the loadings for the MIA Change and Locus scales. The two factor solution has potential for resolving conflicting results in the literature regarding age differences in both metamemory and metamemory/memory performance relationships.
TL;DR: The results from these experiments are consistent with the idea that central cholinergic or cholinoceptive neurons are critically involved in amygdala kindling, and the prophylactic effects of scopolamine are produced in the central nervous system and not in the periphery.
TL;DR: In this article, the authors present updated results from the UA1 experiment on cross sections times leptonic branching ratios for intermediate vector bosons produced in proton-antiproton collisions at a centre-of-mass energy of 0.630 TeV.
TL;DR: Binding studies with chimeric 5SRNA molecules indicated that the increased binding strength of somatic 5S RNA is conferred by nucleotide substitutions in the 5' half of the molecule, similar to the differential affinity of TFIIIA for the two genes.
Abstract: The interaction of TFIIIA with deletion fragments of Xenopus 5S RNA has been quantified using a nitrocellulose filter binding assay. TFIIIA binding was found to be more sensitive to the deletion of nucleotides from the 5' terminus of the 5S RNA as opposed to the 3' terminus. These effects have been correlated to the changes in RNA secondary structure resulting from the deletions. Nucleotides 11-108 of the intact 5S RNA provide the necessary sequence and conformational information required for the binding of TFIIIA. Synthetic 5S RNA genes have been constructed so that in vitro transcription with T7 RNA polymerase yields mature 5S RNA. The transcription factor has a higher affinity for somatic vs. oocyte 5S RNA, similar to the differential affinity of TFIIIA for the two genes. Binding studies with chimeric 5S RNA molecules indicated that the increased binding strength of somatic 5S RNA is conferred by nucleotide substitutions in the 5' half of the molecule.
TL;DR: Weight-specific respiration rates of medusae from the NE Pacific ranged from 0.1 to 0.3, suggesting thatmedusae lack thermal compensation, at least over short time-spans, and daily turnover of carbon due to respiration was estimated to equal 2–10% of total body carbon.
TL;DR: Sequential acid pH dissociation, differential ultracentrifugation, and neutral pH reassociation were used to partially purify serotypically distinct flagella from three strains of Campylobacter jejuni and the two antigenic phases of flagellins of Campyobacter coli VC167.
Abstract: Sequential acid pH dissociation, differential ultracentrifugation, and neutral pH reassociation were used to partially purify serotypically distinct flagella from three strains of Campylobacter jejuni and the two antigenic phases of flagella of Campylobacter coli VC167. Each C. jejuni flagellin and C. coli VC167 antigenic phase 1 flagellin were purified to homogeneity by reverse-phase high-performance liquid chromatography with a C8 Spheri-10 column. C. coli VC167 antigenic phase 2 was purified to homogeneity by ion-exchange chromatography with a Mono-Q column. Amino acid compositional analysis put the C. jejuni flagellin molecular weight in the range 63,200 to 63,800 and the C. coli antigenic phase 1 and 2 flagellins at 61,500 and 59,500, respectively. The amino acid compositions of the C. jejuni were similar to each other and to the C. coli VC167 antigenic phase 1 and phase 2 flagellins. One-dimensional peptide mapping of the C. jejuni flagellins by partial digestion with trypsin or chymotrypsin confirmed the structural similarities of the C. jejuni flagellins and the C. coli VC167 antigenic phase 1 flagellin and showed that C. coli VC167 antigenic phase 2 flagellin was structurally distinct from the phase 1 flagellin. The antigenic phase 2 flagellin was especially sensitive to digestion by chymotrypsin. Amino-terminal sequence analysis showed that the 20 N-terminal amino acids of the Campylobacter flagellins were highly conserved. The Campylobacter flagellins also shared limited sequence homology with the N-terminal sequences reported for Salmonella and Bacillus flagellins. Images
TL;DR: In this paper, a mass limit on a fourth generation charged lepton of m L >41 GeV / c 2 (90% CL) and a limit on the number of additional neutrino species of n ⩽7 (90%) were derived.
01 Jan 1987
TL;DR: In this article, an analysis of the space distribution of metal-poor RR Lyrae stars from recent surveys suggests that the Galactic halo can be described in terms of a flattened inner component, which is dominant at the sun's position, and a spherical outer component.
Abstract: An analysis of the space distribution of metal-poor RR Lyrae stars from recent surveys suggests that the Galactic halo can be described in terms of a flattened (c/a ~ 0.6; vertical scale height ~ 1.6 kpc) inner component, which is dominant at the sun’s position, and a spherical outer component. The model is consistent with faint star counts if the local disk to halo star density ratio is ~ 150: 1. The space distribution of metal-poor globular clusters is also consistent with the model. The similarity in \( \left[ {\frac{{\text{Fe}}} {\text{H}}} \right] \) distributions between the inner and outer subsamples of globular clusters suggests that the dominant flattening mechanism is due to the dynamical evolution of an extant population of stars and clusters, rather than to a process involving gaseous dissipation and star formation with accompanying metal enrichment.
TL;DR: In Saanich Inlet, medusae and ctenophores were significant consumers of commercially important euphausiids (eggs and larvae), and are probably competitors of juvenile salmon for these same prey.
TL;DR: In this paper, the authors presented an analysis of the shock-wave configurations which will occur when a plane shock is incident on a double wedge for which the second wedge may have a greater (concave case) or a smaller (convex case) inclination than the first wedge.
Abstract: An analysis is presented of the shock-wave configurations which will occur when a plane shock is incident on a double wedge for which the second wedge may have a greater (concave case) or a smaller (convex case) inclination than the first wedge. It is shown that seven different reflection processes may be expected depending on the Mach number of the incidnet shock Mi and the two wedge angles θ1w and θ2w. These processes may be defined by seven regiouns in the (θ1w,θ2w)-plane, for a given value of Mi. Each of the seven processes has been verified by sequences of shadowgraph and schlieren photographs.A shock-polar analysis of each of the seven processes has provided infomation about the pressure changes and the wave structures which develop immediately behind the main reflections along the wedge surfaces. These wave structures have been verified experimentally, and two types have been observed; one normal to the reflecting surface, and the other in the form of a regular reflection. The criteria to determine which of thses configurations will occur have not yet been established.It is believed that the present study will be of value in predicting the loading of shock waves on structures, and may lead to a better understanding of shock reflections form concave and convex cylindrical surfaces.
TL;DR: In this article, the authors considered the multiplication of certain classes of operators of fractional calculus defined in terms of the Gaussian hypergeometric function, and presented solutions of various boundary value problems involving the celebrated Euler-Darboux equation.
TL;DR: Results from the Victoria Day Care Research Project (VDCRP), which focused on the research triad of parents-children-caregivers, indicate that there are significant differences among parents who use licensed center-based day care, licensed family day care homes, and unlicensed familyDay care homes.