Showing papers by "University of Victoria published in 1990"
TL;DR: In this article, an integrated framework that illustrates the major components of non-consumptive wildlife recreation and links between research areas in ecology, animal behaviour, recreation, tourism and existing wildlife management institutions is presented.
449 citations
TL;DR: The results provide support for gender intensification, but the role of pubertal timing may not be as strong as previously supposed.
Abstract: This longitudinal study of 200 young adolescent girls and boys (mean age 11.6 years in sixth grade) investigated the hypothesis that differences in masculinity, femininity, and sex role attitudes would intensify across the sixth, seventh, and eighth grades (between 11 and 13 years of age) and that pubertal timing (early, on time, late) would play a role in this intensification. Analyses revealed that sex differences in masculinity and sex role attitudes increased across grades, but not sex differences in femininity. Pubertal timing was not associated with this gender divergence, although the evidence is equivocal for boys. The results provide support for gender intensification, but the role of pubertal timing may not be as strong as previously supposed.
338 citations
TL;DR: In this article, the general characteristics of inelastic proton-antiproton collisions at the CERN SPS Collider were studied with the UA1 detector using magnetic and calorimetric analysis.
295 citations
TL;DR: Exile is a way of surviving in the face of the dead father, of gambling with death, which is the meaning of life, of stubbornly refusing to give in to the law of death.
Abstract: You will have understood that I am speaking the language of exile. This language of the exile muffles a cry, it doesn't ever shout . . . Our present age is one of exile. How can we avoid sinking into the mire of common sense, if not by becoming a stranger to one's own country, language, sex and identity? Writing is impossible without some kind of exile. Exile is already in itself a form of dissidence, since it involves uprooting oneself from a family, a country or a language. More importantly, it is an irreligious act that cuts all ties, for religion is nothing more than membership of a real or symbolic community which may or may not be transcendental, but which always constitutes a link, a homology, an understanding. The exile cuts all links, including those that bind him to the belief that the thing called life has A Meaning guaranteed by the dead father. For if meaning exists in a state of exile, it nevertheless finds no incarnation, and is ceaselessly produced and destroyed in geographical and discursive formations. Exile is a way of surviving in the face of the dead father, of gambling with death, which is the meaning of life, of stubbornly refusing to give in to the law of death . . . This ruthless and irreverent dismantling of the workings of discourse, thought, and existence is . . . the work of a dissident. Such dissidence requires ceaseless analysis, vigilance and will to subversion, and therefore necessarily enters into complicity with other dissident practices in the modern Western world. For true dissidence today is perhaps simply what it has always been: thought.
256 citations
TL;DR: A complete global analysis is given which uses a new result to establish the nonexistence of periodic solutions and three explicit threshold parameters which respectively govern the increase of the total population, the existence and stability of an endemic proportion equilibrium and the growth of the infective population.
Abstract: An S----I----R----S epidemiological model with vital dynamics in a population of varying size is discussed. A complete global analysis is given which uses a new result to establish the nonexistence of periodic solutions. Results are discussed in terms of three explicit threshold parameters which respectively govern the increase of the total population, the existence and stability of an endemic proportion equilibrium and the growth of the infective population. These lead to two distinct concepts of disease eradication which involve the total number of infectives and their proportion in the population.
239 citations
TL;DR: Imposex (male genitalia imposed on females) in shoreline whelks and other Neogastropod molluscs is reported in S.E. Asia (Singapore, Malyasia and Indonesia) as mentioned in this paper.
211 citations
211 citations
TL;DR: The predictive relationships between an array of cognitive process and intellectual ability variables and text- and word-recall performance were examined and there is some evidence to suggest that the pattern of ability-performance relationships varies across age, but such interactions appear to be relatively small.
Abstract: The predictive relationships between an array of cognitive process and intellectual ability variables and text- and word-recall performance were examined. A sample of 584 men and women from 3 age groups (19-36, 55-69, and 70-86 years) completed a battery of 23 tasks marking 2 latent criterion variables and 10 latent predictor variables. The results indicated that (a) individual differences in process and ability variables predict performance on text and word recall, accounting for approximately half of the variance; (b) the pattern of predictors is quite similar for text and word recall; (c) age-related differences in text and word recall can be substantially accounted for by individual differences in constituent abilities, particularly indicators of verbal speed and working memory; and (d) there is some evidence to suggest that the pattern of ability-performance relationships varies across age, but such interactions appear to be relatively small.
178 citations
TL;DR: Cnidarians like hydra have seemingly simple, two-dimensional nervous systems with little or no centralization, but even such systems can be surprisingly complex, and the more advanced cnidarian show neurophysiological specializations as sophisticated as those of many higher invertebrates.
Abstract: Parker's theory of the origin of the nervous system is discussed along with later interpretations. Attention today has shifted from the cellular to the molecular level, and it has become clear that many of the molecules and mechanisms thought of as typically neuronal have homologs or counterparts in non-nervous cells and unicellular organisms. This applies to signalling chemicals, receptors, second messenger systems and ion channels, and also to the production of electrical events. Parker's view of sponges as a group lacking nerves but possessing independent effectors is still acceptable, but some sponges (and also higher animals) employ non-nervous signalling pathways to coordinate their effectors. Thus, nerves are not always necessary for coordinated behavior. Cnidarians like hydra have seemingly simple, two-dimensional nervous systems with little or no centralization, but even such systems can be surprisingly complex, and the more advanced cnidarians show neurophysiological specializations as sophisticated as those of many higher invertebrates. Examples of ingenious cnidarian solutions to behavioral problems are given. No existing animals have ‘elementary’ nervous systems if that term implies the existence of crude or inefficient functional adaptations
155 citations
TL;DR: T. brucei may be a useful model to follow other changes in gene expression, metabolism or ultrastructure during differentiation of a unicellular eucaryote.
Abstract: The differentiation of mammalian stage Trypanosoma brucei bloodstream forms comprising predominantly parasites of intermediate and stumpy morphology to the procyclic forms characteristic for the insect midgut stage was studied in vitro. Differentiation of the cell population occurred synchronously as judged by the synthesis of the surface glycoprotein, procyclin, characteristic of the arising procyclic forms and the loss of the membrane-form variant surface glycoprotein, the coat protein of bloodstream forms. The change in surface antigens took place within 12 h in the absence of cell growth; subsequently, the procyclic cells divided exponentially. As defined in this study, T. brucei may be a useful model to follow other changes in gene expression, metabolism or ultrastructure during differentiation of a unicellular eucaryote.
150 citations
TL;DR: Epileptic patients who had undergone the carotid amytal test were assessed on a variety of measures of verbal and non-verbal ability, and patients with atypical speech patterns performed more poorly than their left hemisphere speech counterparts on a wide variety of non- verbal tests.
TL;DR: The results suggest that urea is synthesized and excreted by the toadfish primarily in situations that limit ammonia excretion, and the ornithineurea cycle in theToadfish liver primarily maintains low concentrations of ammonia within the fish.
Abstract: Under long-term (24 h) control measurements, significant urea was excreted (15 to 90% of excreted nitrogen) byOpsanus beta (Goode and Bean) collected in 1989 from Biscayne Bay, Florida, USA. Urea excretion rates and plasma urea concentrations were not affected by antibiotic treatments which decreased intestinal microbe populations. These results suggest that nitrogen recycling by gut microbe urease is probably not significant in this species. Urea excretion rates increased significantly following 8 h of air-exposure and in response to high levels of NH4Cl. These results suggest that urea is synthesized and excreted by the toadfish primarily in situations that limit ammonia excretion. Thus, the ornithineurea cycle in the toadfish liver primarily maintains low concentrations of ammonia within the fish. High levels of variability in urea excretion rates and variation in response to air-exposure suggest that urea synthetic rates are affected by immediate past environmental conditions.
TL;DR: It is suggested that the combination of differential herd growth, differential participation in the cash market, and differential loss to the drought has contributed to a polarization within Ariaal of rich and poor, resulting in rural proletarianization and urban migration.
Abstract: This paper examines the effects of the 1984 drought upon household wealth differences in a community of Ariaal pastoralists of northern Kenya. The database consists of 1985 post-drought livestock counts and informants' statements of species-specific drought loss, compared to 1976 livestock counts on the same 38 households. The analysis confirms the hypothesis that the drought resulted in increased household wealth inequalities. It is suggested that the combination of differential herd growth, differential participation in the cash market, and differential loss to the drought has contributed to a polarization within Ariaal of rich and poor, resulting in rural proletarianization and urban migration.
TL;DR: Results suggest that the ability to sustain attention increases with age and does not vary by gender, and within-age-level comparisons between groups of ADDH and controls would be more clinically sensitive than across- age-group comparisons.
Abstract: It has been suggested that children with ADDH have specific difficulties in sustained attention. Despite some early studies supporting this position, many recent reports using continuous performance tests (CPTs) have failed to confirm this hypothesis. Possible reasons for this discrepancy are outlined and an attempt to corroborate and extend an earlier study (Sykes, Douglas, & Morgenstern, 1973) was undertaken. CPT results in normal children indicated that changes in performance over time, although not affected by gender, were influenced by age. Data from ADDH subjects indicated that they performed significantly more poorly with time on task than did controls. These results suggest that the ability to sustain attention increases with age and does not vary by gender. Furthermore, difficultues in the ability to sustain attention can be demonstrated in children with ADDH. Finally, it is suggested that within-age-level comparisons between groups of ADDH and controls would be more clinically sensitive than across-age-group comparisons. Language: en
TL;DR: In this article, a random pulse-width modulation technique for voltage-controlled power inverters is proposed, which is based on the non-repetitiveness of the switching pattern, simplicity of the hardware, and uncommonly high limits of switching frequency.
Abstract: As an alternative to the existing deterministic pulse-width modulation methods, a random pulse-width modulation technique for voltage-controlled power inverters is proposed. Advantages of the technique include non-repetitiveness of the switching pattern, simplicity of the hardware, and uncommonly high limits of switching frequency. A prototype random pulse-width modulator is described and experimental results are presented.
TL;DR: It is concluded that the VC stick will help a small subpopulation of Parkinson's disease patients with freezing, and this subpopulation can be identified with the initial office visit trial.
Abstract: We evaluated a modified inverted walking stick [visual cue (VC) stick] in Parkinson's disease patients with freezing episodes. Patients underwent baseline trials on a 60-ft track with four walking conditions: unassisted, with a straight walking stick, with the VC stick, and on the track with parallel lines spaced every 12 in. Patients completed three trials of each condition in a randomized order, with total course time and number of freezes recorded. Patients were given the VC stick to use at home until subjective maximum functional benefit was obtained and were then brought back for a follow-up objective evaluation. Eight patients completed the study. The straight stick and VC stick worsened patient performance as a group, while the parallel lines significantly improved group performance. However, two of the eight patients showed benefit from the VC stick. Improvement with parallel lines did not predict improvement with the VC stick. On follow-up trials, the two who initially showed improvement with the VC stick continued to show improvement, while none of the other patients showed additional benefit from a learning effect. We conclude that the VC stick will help a small subpopulation of Parkinson's disease patients with freezing, and this subpopulation can be identified with the initial office visit trial.
TL;DR: The potential of the WOTAN technique to estimate oceanic winds from underwater ambient sound is thoroughly evaluated in this article, where anemometer winds and sound spectrum levels at 11 frequencies in the range 3-25 kHz from the FASINEX Experiment are used to establish both the frequency and wind speed dependencies of ambient sound and tested using independent data from four other deployments, and found to hold in the deep ocean in the OCEAN STORMS but not in shallow coastal waters.
Abstract: The potential of the WOTAN technique to estimate oceanic winds from underwater ambient sound is thoroughly evaluated. Anemometer winds and sound spectrum levels at 11 frequencies in the range 3–25 kHz from the FASINEX Experiment are used to establish both the frequency and wind speed dependencies of ambient sound. These relationships are then tested using independent data from four other deployments, and found to hold in the deep ocean in the OCEAN STORMS but not in shallow coastal waters. The OCEAN STORMS ambient-sound wind speed estimates are within ±0.5 m s−1 of anemometer values for wind speeds between 4 and 15 m s−1. Causes of differences, including disequilibrium of the surface wave field, are discussed and it is argued that they are no larger than expected. The procedure for processing ambient-sound data is developed. It includes temperature dependent calibration detection of shipping and precipitation contamination, and standardization of measurements to 1 m depth. The latter procedure al...
TL;DR: In this paper, a small herd of caribou, Rangifer tarandus, migrated in April to the islands in Lake Nipigon, Ontario where they remained for the summer.
TL;DR: One of these synthetic antigens, inoculated subcutaneously with adjuvant, was shown to specifically induce proliferation of the Th1 subset and provided immunoprotection against two species of Leishmania parasites.
Abstract: Using the predictive algorithm of Rothbard and Taylor (1988. EMBO J. 7:93) and the primary structure of gp63 (Button, L., and M.R. McMaster. 1988. J. Exp. Med. 167:724; Miller, R.A., S.G. Reed, and M. Parsons. 1990. Mol. Biochem. Parasitol. 39:267) we have been able to delineate the structures of a number of gp63 T-cell epitopes which stimulate the proliferation of CD4+ cells. One of these synthetic antigens, inoculated subcutaneously with adjuvant, was shown to specifically induce proliferation of the Th1 subset and provided immunoprotection against two species of Leishmania parasites.
TL;DR: The IBM PC keyboard is a convenient response panel for subjects in a reaction time task when the stimuli are presented on the same machine but there is a mean delay of about 10 msec and a random error of ±7.5 msec, which is acceptable for typical single response experimental situations.
Abstract: The IBM PC keyboard is a convenient response panel for subjects in a reaction time task when the stimuli are presented on the same machine. However, there is a mean delay of about 10 msec and a random error of ±7.5 msec (±5 msec on the AT or PS/2). Our analyses show that for typical single response experimental situations, this added variance is acceptable. With mouse buttons, timing resulted in a delay of 31 ±2 msec if the mouse ball was steady but 45 ±15 msec if it was moving, and a 25-msec refractory period before a second response could be detected. With keys connected to the game port, timing was accurate to 1 msec. For timing the interval between two nearly simultaneous responses, only the game port method is recommended. Any research application should provide an external check on reaction timing accuracy and should correct any mean error.
TL;DR: The cytolytic toxin aerolysin was found to form ion channels which displayed slight anion selectivity in planar lipid bilayers and there is evidence that oligomerization is a necessary step in channel formation.
Abstract: The cytolytic toxin aerolysin was found to form ion channels which displayed slight anion selectivity in planar lipid bilayers. In voltage-clamp experiments the ion current flowing through the channels was homogeneous indicating a defined conformation and a uniform size. The channels remained open between -70 to +70 mV, but outside this range they underwent voltage-dependent inactivation which was observed as open-closed fluctuations at the single-channel level. Zinc ions not only prevented the formation of channels by inhibiting oligomerization of monomeric aerolysin but they also induced a closure of preformed channels in a voltage-dependent fashion. The results of a Hill plot indicated that 2-3 zinc ions bound to a site within the channel lumen. Proaerolysin, and a mutant of aerolysin in which histidine 132 was replaced by an asparagine, were both unable to oligomerize and neither could form channels. This is evidence that oligomerization is a necessary step in channel formation.
TL;DR: The NART estimates in the mild and moderate/severe dementia groups differed significantly from those for the very mildly demented patients and controls, suggesting that the applicability of the NART in estimating premorbid IQ in dementia may be limited.
Abstract: Two methods for estimating premorbid IQ were employed in a sample of 199 dementia patients and 26 control subjects: (1) the National Adult Reading Test (NART), a present ability measure, and (2) an age, sex, race, education and occupation regression formula-a demographically based estimate. The dementia sample consisted of probable Alzheimer's disease, multi-inf arct dementia and a mixture of the two. Controls consisted of the spouses of the patient sample. The patient sample was divided into three levels of dementia severity equated for age and level of education. The NART estimates in the mild and moderate/severe dementia groups differed significantly from those for the very mildly demented patients and controls. The results suggest that the applicability of the NART in estimating premorbid IQ in dementia may be limited.
TL;DR: Radioimmunoassay using different GnRH antisera after high-performance liquid chromatography (HPLC) revealed that the dominant form of GnRH is the mammalian form both during ontogenesis in the rat and in the adult guinea pig known to have variant forms of other peptide hormones.
TL;DR: A major substrate for vent organisms on Juan de Fuca and Explorer Ridges of the northeast Pacific is the polymetallic sulphide chimney as mentioned in this paper, where the deposition processes and subsequent growth of such chimneys provide a dynamic and extreme habitat that changes rapidly.
TL;DR: Purified LPG or phosphoglycan, the delipidated form of the LPG molecule, was shown to bind to a variety of different cell types in a temperature-independent manner and suggest a further mechanism(s) by which Leishmania LPG might be involved in parasite pathogenicity and virulence.
Abstract: Murine peritoneal macrophages were infected with living, virulent Leishmania donovani promastigotes. At intervals after infection, the macrophage surfaces were probed for the expression of lipophosphoglycan (LPG) epitopes by immunofluorescence with anti-LPG monoclonal antibodies. A repeating phosphorylated disaccharide epitope of LPG was detected as early as 5 to 10 min postinfection and was initially localized to the immediate area of internalization of the promastigote into the macrophage. The epitopes were evenly distributed over the entire macrophage surface by 25 min postinfection. Treatments which inhibited macrophage phagolysosomal degradation processes had no effect on epitope expression, whereas reagents that affected macrophage membrane flow and, thus, phagocytosis drastically reduced or abolished expression. Purified LPG or phosphoglycan, the delipidated form of the LPG molecule, was also shown to bind to a variety of different cell types in a temperature-independent manner. Since LPG has been implicated as having an immunoprotective role in leishmaniasis, these results suggest a further mechanism(s) by which Leishmania LPG might be involved in parasite pathogenicity and virulence.
TL;DR: Interspecies comparison of muscle and liver tissue levels both for Buttle lake and for uncontaminated British Columbia lakes found that rainbow trout, cutthroat trout and Dolly Varden char respond differently to metals in the environment.
TL;DR: Thermal denaturation experiments indicated that the antigenicity conferred by the surface-exposed C. fetus S-layer epitopes was unusually resistant to heat, and the thermal stability appeared to be due to the highly organized lattice structure of the S. layer.
Abstract: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of S-layer proteins extracted from Campylobacter fetus strains by using acid glycine buffer showed that the predominant S-layer proteins of different strains had subunit molecular weights in the range of 90,000 to 140,000. Electron microscopy revealed oblique S-layer lattices with a spacing of approximately 5.6 nm (gamma = 75 degrees) on wild-type strains VC1, VC119, VC202, and VC203. Three variants of C. fetus VC119 producing a predominant S-layer subunit protein of different molecular weight (Mr) from that of the parent were also examined. Each variant produced an oblique lattice morphologically indistinguishable from that of the parent. Amino-terminal sequence analysis showed that the S-layer proteins of the VC119 parent and variants were identical up to residue 18 and that this sequence differed from but was related to the first 16 N-terminal residues shared by the S-layer proteins of the three other wild-type C. fetus isolates. Western immunoblot analysis with an antiserum prepared to the VC119 protein and an antiserum prepared to C. fetus 84-40 LP (Z. Pei, R. T. Ellison, R. V. Lewis, and M. J. Blaser, J. Biol. Chem. 263:6416-6420, 1988) showed that strains of C. fetus were capable of producing S-layer proteins with at least four different antigenic specificities. Immunoelectron microscopy with antiserum to the VC119 S-layer protein showed that C. fetus cultures contained cells with immunoreactive oblique S-layer lattices as well as cells with oblique S-layer lattices which did not bind antibody. This suggests that C. fetus S-layer proteins undergo antigenic variation. Thermal denaturation experiments indicated that the antigenicity conferred by the surface-exposed C. fetus S-layer epitopes was unusually resistant to heat, and the thermal stability appeared to be due to the highly organized lattice structure of the S. layer. Protease digestion of purified VC119 S-layer protein revealed a trypsin-, chymotrypsin-, and endoproteinase Glu-C-resistant domain with an apparent Mr of 110,000, which carried the majority of the epitopes of the S-layer protein, and a small enzyme-sensitive domain. The trypsin- and chymotrypsin-resistant polypeptides shared an overlapping sequence which differed from the N-terminal sequence of the intact S-layer protein.
TL;DR: It can be concluded that GLPs are important regulators of hepatic metabolism, influencing identical targets as glucagon, while the mechanisms of action seem to differ.
Abstract: Salmon glucagon-like peptide (GLP), bovine glucagon (B-glucagon) and anglerfish glucagon (AF-glucagon), all activate glucose production in teleost hepatocytes through gluconeogenesis and glycogenolysis, but notable species differences exist in their respective effectiveness. In trout hepatocytes, gluconeogenesis appears to be the main target of hormone action. In eel cells, sampled in November, glycogenolysis was activated threefold, while gluconeogenesis was increased by 12% only. In March, glycogenolytic activation was 1.7-fold, while gluconeogenesis was increased by about 1.7-fold after exposure to B-glucagon. In brown bullhead cells, increases in glycogenolysis from seven- (GLP) to tenfold (B- and AF-glucagon) were noted, while activation of gluconeogenesis was slight. Fragments of two AF-glucagons (19-29) revealed only insignificant metabolic activity. Treatment of eel cells with B-glucagon led to large (up to 20-fold) increases in intracellular cyclic AMP (cAMP) concentrations, while exposure to GLP was accompanied by a modest (less than twofold) increase in cAMP, although metabolic effectiveness (gluconeogenesis and glycogenolysis) was similar for the two treatments. Under identical conditions, brown bullhead cellular cAMP responded poorly. Levels of cAMP peaked within 15 min following hormone application. The results imply that no simple or direct relationship exists between the amount of intracellular cAMP and the metabolic action of the glucagon family of hormones. It can further be concluded that GLPs are important regulators of hepatic metabolism, influencing identical targets as glucagon, while the mechanisms of action seem to differ.
TL;DR: Pollen grains of all genera of Rosaceae surveyed in Canada occur as radially symmetric isopolar monads, except some Sanguisorba species which are bexacolporate.
TL;DR: The significance of the body cell and egg cell ultrastructure is discussed in light of recent restriction fragment length polymorphism studies of plastid and mitochondrial inheritance in the Pinaceae.
Abstract: Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) ovules were used to study the method of pollen tube formation and penetration of the nucellus, the movement of the body cell down the pollen tube and development of the archegonia. No pollination drop forms but nucellar tip cells produce a minute secretion that may initiate pollen tube formation. Pollen tubes penetrate the nucellus causing degeneration of nucellar cells in contact with the pollen tube tip. The body cell becomes highly lobed and the tube cytoplasm forms thin sheets between the lobes. This may be the mechanism by which the large body cell is pulled down the narrow pollen tube. Body cell plastids and mitochondria remain unaltered during pollen tube growth, whereas tube cell organelles show signs of degeneration. The pollen tube penetrates the megaspore wall and settles in the archegonial chamber. During pollen elongation and pollen tube growth the egg matured. Egg cell plastids were transformed into large inclusions which filled the periphery of the egg while mitochondria migrated to the perinuclear zone. The neck cells, ventral canal cell and archegonial jacket cells are described. The significance of the body cell and egg cell ultrastructure is discussed in light of recent restriction fragment length polymorphism studies of plastid and mitochondrial inheritance in the Pinaceae.