Showing papers by "Université du Québec à Montréal published in 2000"

On the Assessment of Situational Intrinsic and Extrinsic Motivation: The Situational Motivation Scale (SIMS)

Abstract: The purpose of the present research was to develop and validate a situational (or state) measure of motivation, the Situational Motivation Scale (SIMS) The SIMS is designed to assess the constructs of intrinsic motivation, identified regulation, external regulation, and amotivation (E L Deci & R M Ryan, 1985, 1991) in field and laboratory settings Five studies were conducted to develop and validate the SIMS Overall, results show that the SIMS is composed of 4 internally consistent factors The construct validity of the scale is also supported by correlations with other constructs as postulated by current theories Moreover, the SIMS is responsive to experimental induction as evidenced by data gathered through a laboratory study In sum, the SIMS represents a brief and versatile self-report measure of situational intrinsic motivation, identified regulation, external regulation, and amotivation

Why Are You Learning a Second Language? Motivational Orientations and Self‐Determination Theory

Abstract: The data for this study were collected in my first year of graduate school for a term paper for a course I was taking from Luc Pelletier. When I began graduate school, Luc also started at the University of Ottawa as a new faculty member, and he taught a course in motivation. I had worked with Richard Clement for a couple of years already as an honors student and as a research assistant and had conducted research on orientations and motivation under his supervision as part of my honors thesis project. Luc was very interested in self-determination theory (SDT) and had worked with Bob Vallerand on an instrument to assess academic motivation from this perspective. Luc and I decided to carry out a study on language learning orientations using SDT and enlisted Richard's and Bob's involvement in the project. As a bilingual institution where all students were required to demonstrate competence in their second language (L2), whether French or English, the University of Ottawa was an ideal setting for this type of research. The project was a first examination of SDT in the language learning context, and to the best of my knowledge it was the only, or at least one of the very few, empirical investigations of intrinsic and extrinsic motivation in the area. It involved the development of a valid and reliable instrument to assess the different subtypes of intrinsic and extrinsic motivation. It also explored the link between these motivational subtypes and various orientations to language learning that had been identified by Clement and Kruidenier (1983), including the travel, friendship, knowledge, and instrumental orientations. The results showed that the instrumental orientation and the SDT external regulation orientation were strongly correlated, and that the travel, friendship, and knowledge orientations were quite highly intercorrelated with identified regulation and intrinsic motivation. Moreover, the instrumental and external regulation orientation scales correlated in similar ways with the hypothesized antecedents of perceived autonomy and competence and the hypothesized consequences of intention to pursue L2 study and anxiety. In addition, the travel, friendship, and knowledge orientations were correlated with the hypothesized antecedents and consequences in a manner similar to intrinsic motivation and identified regulation. These results suggested that Clement and Kruidenier's 4 orientations may be tapping a similar construct as the SDT orientations. My only regret with this study is that I did not include a scale to measure the integrative orientation (Gardner, 1985) to determine its relation with the SDT subtypes. This issue would have to wait until a later study to be addressed. The results of this initial investigation encouraged me to pursue research integrating SDT with other theoretical frameworks of language learning motivation. I believe that the SDT framework has several advantages over some other formulations of learner orientations. SDT offers a parsimonious, internally consistent framework for systematically describing many different orientations in a comprehensive manner. It also offers considerable explanatory power for understanding why certain orientations are better predictors of relevant language learning variables (e.g., effort, persistence, attitudes) than others. Also, by invoking the psychological mechanisms of perceived autonomy, competence, and relatedness, it can account for why certain orientations are evident in some learners and not in others. Moreover, the framework is empirically testable and indeed has stood up well under empirical scrutiny in our studies. Its clear predictions may also be particularly valuable in applying the theory in language teaching and program development. [The present article first appeared in Language Learning, 50 (1), 2000, 57–85]

The Influence of Facial Emotion Displays, Gender, and Ethnicity on Judgments of Dominance and Affiliation

Abstract: Facial expressions of emotions convey not only information about emotional states but also about interpersonal intentions The present study investi- gated whether factors known to influence the decoding of emotional expressions— the gender and ethnicity of the stimulus person as well as the intensity of the ex- pression—would also influence attributions of interpersonal intentions For this, 145 men and women rated emotional facial expressions posed by both Caucasian and Japanese male and female stimulus persons on perceived dominance and affil- iation The results showed that the sex and the ethnicity of the encoder influenced observers' ratings of dominance and affiliation For anger displays only, this influ- ence was mediated by expectations regarding how likely it is that a particular en- coder group would display anger Further, affiliation ratings were equally influenced by low intensity and by high intensity expressions, whereas only fairly intense emo- tional expressions affected attributions of dominance

Landscape-scale disturbances and changes in bird communities of boreal mixed-wood forests

Abstract: Bird community response to both landscape-scale and local (forest types) changes in forest cover was studied in three boreal mixed-wood forest landscapes modified by different types of disturbances: (1) a pre-industrial landscape where human settlement, agriculture, and logging activities date back to the early 1930s, (2) an industrial timber managed forest, and (3) a forest dominated by natural disturbances Birds were sampled at 459 sampling stations distributed among the three landscapes Local habitat and landscape characteristics of the context surrounding each sampling station (500-m and 1-km radius) were also computed Bird communities were influenced by landscape-scale changes in forest cover The higher proportion of early-successional habitats in both human-disturbed landscapes resulted in significantly higher abundance of early-successional bird species and generalists The mean number of mature forest bird species was significantly lower in the industrial and pre-industrial landscapes than in the natural landscape Landscape-scale conversion of mature forests from mixed-wood to deciduous cover in human-disturbed landscapes was the main cause of changes in mature forest bird communities In these landscapes, the abundance of species associated with mixed and coniferous forest cover was lower, whereas species that preferred a deciduous cover were more abundant Variation in bird community composition determined by the landscape context was as important as local habitat conditions, suggesting that predictions on the regional impact of forest management on songbirds with models solely based on local scale factors could be misleading Patterns of bird species composition were related to several landscape composition variables (proportions of forest types), but not to configuration variables (eg, interior habitat, amount of edge) Overall, our results indicated that the large-scale conversion of the southern portion of the boreal forest from a mixed to a deciduous cover may be one of the most important threats to the integrity of bird communities in these forest mosaics Negative effects of changes in bird communities could be attenuated if current forestry practices are modified toward maintaining forest types (deciduous, mixed-wood, and coniferous) at levels similar to those observed under natural disturbances

Dynamics of carbon and nitrogen mineralization in relation to stand type, stand age and soil texture in the boreal mixedwood.

Abstract: In the boreal mixed forest, stand composition generally changes from deciduous to mixed to coniferous stands during postdisturbance succession. Our objective was to determine the influence of forest composition on the quality of soil nitrogen and carbon as determined by C and N mineralization during the course of a long-term in vitro incubation (282 days). Three stand types (Populus tremuloides, Betula papyrifera, and conifers (mixture of Abies balsamea and Picea glauca)), of two ages (50 and 124 years since fire) growing on two soil types (clay and till) were considered. Expressed on an organic C basis, our results showed a greater N mineralization for deciduous than coniferous stands, both in the mineral soil and the forest floor, a higher N mineralization in the mineral soil of older stands as compared with young ones, and in till than in clay soils. Mineralization of C was higher in the forest floor of clay soils as compared to till soils while the opposite was found in the mineral soil. It was also higher in both soil layers of older sites. The observed diAerences in N and C mineralization among stand types, stand ages and deposits appeared to be due to diAerences in the most labile fraction of soil organic matter because these diAerences were observed within 100 days of incubation. The ratio of C mineralized‐N mineralized was greater in coniferous than deciduous soils in both soil layers, indicating a lesser quality of organic matter under coniferous stands. Despite significant diAerences among the above-listed factors for N and C mineralization on an organic C basis, the pool size of mineralized (or mineralizable) N and C was generally not significantly diAerent between the diAerent forest and soil types because of an inverse relationship between quality and quantity of soil organic matter. Correlation and multiple regression analysis indicated that clay content (negatively), C‐N ratio (negatively), available P as well as exchangeable Mn were related to the mineralization of N. 7 2000 Elsevier Science Ltd. All rights reserved.

Variation in the intraspecific relationship between fish length and intensity of parasitic infection: biological and statistical causes.

Abstract: In a meta-analysis, the overall mean correlation between fish length and the intensity of parasitic infections derived from 76 different host-parasite species was positive but weak and non-significant, following corrections for sample size. Whether the parasites were acquired by ingestion or by skin contact had no influence on the strength of the relationship. For cestodes, larval digeneans, and gnathiid isopods, however, the mean correlation between fish length and intensity of infection was significant. Some statistical parameters influenced the strength of the raw correlations computed within samples and thus led to over- or under-estimation of the true relationship. Sample size correlated negatively with the value of the correlation coefficients, whereas range in both fish lengths and intensities of infection correlated positively with the value of the correlation coefficients. Distinguishing between statistical noise and the biological processes shaping the size v. intensity relationship will be important if this relationship is to be incorporated into fish population models.

Emotional expressivity in men and women: Stereotypes and self-perceptions

Abstract: Three studies were conducted to assess prevalent stereotypes regarding men's and women's emotional expressivity as well as self-perceptions of their emotional behaviour. Emotion profiles were employed to assess both modal emotional reactions and secondary emotional reactions to hypothetical events and personal experiences. In Study 1 we asked how men and women in general would react to a series of hypothetical emotional events. In Study 2 we asked how participants themselves expected to react to these same situations and in Study 3 we asked participants to report a personal emotional event in narrative form. Two gender differences emerged across all three studies. Specifically, women were expected to be more likely to react with sadness to negative emotion-eliciting events in general. They also expected themselves to be more likely to react with sadness as well as to cry and to withdraw more when experiencing negative emotional events. Finally, women report more sadness when describing personal events. In...

Methylmercury exposure affects motor performance of a riverine population of the Tapajós river, Brazilian Amazon

Abstract: Gold mining and deforestation in the Brazilian Amazon are increasing mercury pollution of the extensive water system, exposing riverine populations to organic mercury through fish-eating. The aim of the present study was to evaluate the effect of such exposure on motor performance. This cross-sectional study was carried out in May 1996, in a village located on the banks of the Tapajos river in the Amazonian Basin, Brazil. Information concerning sociodemographics, health, smoking habits, alcohol drinking, dietary habits and work history were collected using an interview-administered questionnaire. Mercury concentrations were measured by cold vapor atomic absorption in blood and hair of each participant, of whom those aged between 15 and 79 years were assessed for motor performance (n=84). Psychomotor performance was evaluated using the Santa Ana manual dexterity test, the Grooved Pegboard Fine motor test and the fingertapping motor speed test. Motor strength was measured by dynamometry for grip and pinch strength. Following the exclusion of 16 persons for previous head injury, working with mercury in the gold-mining sites, or for diabetes, the relationship between performance and bioindicators of mercury was examined using multivariate statistical analyses, taking into account covariables. All participants in the study reported eating fish, which comprised 61.8% of the total meals eaten during the preceding week. The median hair total mercury concentration was 9 μg/g. Organic mercury accounted for 94.4 ± 1.9% of the total mercury levels. Multivariate analysis of variance indicated that hair mercury was inversely associated with overall performance on the psychomotor tests, while a tendency was observed with blood mercury. Semipartial regression analyses showed that hair total mercury accounted for 8% to 16% of the variance of psychomotor performance. Neither hair nor blood total mercury was associated with the results of the strength tests in women and men. Although dose-effect relationships were observed in this cross-sectional study, they may reflect higher exposure levels in the past. The findings of this study demonstrated neurobehavioral manifestations of subtle neurotoxic effects on motor functions, associated with low-level methylmercury exposure.

Planktonic production and respiration in oligotrophic Shield lakes

Abstract: A precise oxygen method was used to measure primary production, community respiration and to determine the importance of exogenous organic carbon as an energy source to planktonic communities in the epilimnion of 12 oligotrophic to mesotrophic Shield lakes. Median photosynthetic parameters observed with the oxygen method were up to twice as high as those measured with 14 C in other oligotrophic Shield lakes. Gross photosynthesis was almost always larger than community respiration, with a median P : R ratio of 1.7. We observed strong relationships between respiration and gross photosynthesis, but could not detect any significant trend between respiration or the P : R ratio and the concentration of dissolved organic carbon (DOC). DOC appeared to depress both photosynthesis and respiration. These results argue against the importance of exogenous organic carbon supply as a significant energy source to freshwater planktonic communities. Previously low P : R ratios reported for oligotrophic fresh waters may be due to the uncertain meaning of 14 C production data.

Development of biodegradable films from whey proteins by cross-linking and entrapment in cellulose.

Abstract: When cross-linked by heating or by gamma-irradiation and entrapped in cellulose, whey proteins can generate insoluble biofilms with good mechanical properties and high resistance to attack by proteolytic enzymes. Interchain cross-linking of proteins generated an increase in the puncture strength, and a decrease in water vapor permeability. Gelatin was added in film formulation as a stabilizer to improve the puncture strength and film appearance. The structure of the biofilms was also analyzed. SDS-PAGE revealed that heating and gamma-irradiation produce an increase of the molecular weight of the cross-linked protein. Size exclusion chromatography showed a molecular mass of 40 kDa for un-cross-linked whey proteins, whereas for the soluble fractions of the cross-linked proteins, molecular distributions were between 600 and 3800 kDa for the heated proteins and between 1000 and 2000 kDa for gamma-irradiated proteins. No major alteration of the structural conformation of the proteins was observed by FTIR for biofilms obtained after heat treatment, whereas gamma-irradiation induced some modifications in the protein structure. X-ray diffraction analysis suggests that cross-linking by gamma-irradiation seems to modify the conformation of proteins, which became more ordered and more stable.

Cognitive decline in patients with Cushing's syndrome.

Abstract: Chronic exposure to elevated glucocorticoid levels in Cushing's syndrome (CS), is associated with deficits in cognitive function and in emotion. The hippocampus plays a crucial role in the behavioral manifestations of the syndrome as it is richest in glucocorticoid receptors and is thus particularly vulnerable to glucocorticoid excess. The wide distribution of glucocorticoid receptors throughout the cerebral cortex, however, suggests that several cognitive functions can also be affected by the dysregulation of glucocorticoids. In this study, we investigated how an excess of glucocorticoid hormones affects cognitive processes. Nineteen patients with chronic hypercortisolemia due to CS were compared to healthy controls matched for age, sex, education, and occupation in tests of processing of visual and spatial information, memory, reasoning and concept formation, language and verbal functions, and attention. Multivariate and univariate analyses revealed overall differences in tests of treatment of visual and spatial information, reasoning and concept formation as well as in verbal and language performance, with poorer performance from CS patients. Differences were also observed in nonverbal aspects of memory and in attention tasks. The results suggest that chronic exposure to elevated levels of cortisol is associated with deficits in several areas of cognition, particularly those involving processing of selective attention and visual components. This study also shows that hormones play an important role in the modulation of cognitive function and that their influence on cerebral structure and function merits closer scrutiny. (JINS, 2000, 6, 20–29.)

Stimulation of the mesencephalic locomotor region elicits controlled swimming in semi-intact lampreys.

Abstract: The role of the mesencephalic locomotor region (MLR) in initiating and controlling the power of swimming was studied in semi-intact preparations of larval and adult sea lampreys. The brain and the rostral portion of the spinal cord were exposed in vitro, while the intact caudal two-thirds of the body swam freely in the Ringer's-containing chamber. Electrical microstimulation (2-10 Hz; 0. 1-5.0 microA) within a small periventricular region in the caudal mesencephalon elicited well-coordinated and controlled swimming that began within a few seconds after the onset of stimulation and lasted throughout the stimulation period. Swimming stopped several seconds after the end of stimulation. The power of swimming, expressed by the strength of the muscle contractions and the frequency and the amplitude of the lateral displacement of the body or tail, increased as the intensity or frequency of the stimulating current were increased. Micro-injection of AMPA, an excitatory amino acid agonist, into the MLR also elicited active swimming. Electrical stimulation of the MLR elicited large EPSPs in reticulospinal neurons (RS) of the middle rhombencephalic reticular nucleus (MRRN), which also displayed rhythmic activity during swimming. The retrograde tracer cobalt-lysine was injected into the MRRN and neurons (dia. 10-20 microm) were labelled in the MLR, indicating that this region projects to the rhombencephalic reticular formation. Taken together, the present results indicate that, as higher vertebrates, lampreys possess a specific mesencephalic region that controls locomotion, and the effects onto the spinal cord are relayed by brainstem RS neurons.

Reconstruction of sea-surface temperature, salinity, and sea-ice cover in the northern North Atlantic during the last glacial maximum based on dinocyst assemblages

Abstract: Past sea-surface conditions over the northern North Atlantic during the last glacial maximum were examined from the study of 61 deep-sea cores. The last glacial maximum time slice studied here corresponds to an interval between Heinrich layers H2 and H1, and spanningabout 20-16 ka on a 14C time scale. Transfer functions based on dinocyst assemblages were used to reconstruct sea-surface temperature, salinity, and sea-ice cover. The results illustrate extensive sea-ice cover along the eastern Canadian margins and sea-ice spreading, only during winter, over most of the northern North Atlantic. On the whole, much colder winter prevailed, despite relatively mild conditions in August (10-15°C at most offshore sites), thus suggesting a larger seasonal contrast of temperatures than today. Lower salinity than at present is reconstructed, especially along the eastern Canadian and Scandinavian margins, likely because of meltwater supply from the surrounding ice sheets. These reconstructions contrast with those established by CLIMAP on the basis of planktonic foraminifera. These differences are discussed with reference to the stratigraphical frame of the last glacial maximum, which was not the coldest phase of the last glacial stage. The respective significance of dinocyst and foraminifer records is also examined in terms of the thermohaline characteristics of surface waters and the vertical structure of upper water masses, which was apparently much more stratified than at present in the northern North Atlantic, thus preventing deep-water formation.

The Mental Representation of Semitic Words

Abstract: This article is concerned with external evidence bearing on the nature of the units stored in the mental lexicons of speakers of Semitic languages. On the basis of aphasic metathesis errors we collected in a single case study, we suggest that roots can be accessed as independent morphological units. We review documented language games and slips of the tongue that lead to the same conclusion. We also discuss evidence for the morphemic status of templates from aphasic errors, language games, and slips of the tongue. We conclude that the available external evidence is best accounted for within a morpheme-based theory of morphology that forms words by combining roots and templates.

Cytogenetic damage related to low levels of methyl mercury contamination in the Brazilian Amazon

Abstract: The mercury rejected in the water system, from mining operations and lixiviation of soils after deforestation, is considered to be the main contributors to the contamination of the ecosystem in the Amazon Basin. The objectives of the present study were to examine cytogenetic functions in peripheral lymphocytes within a population living on the banks of the Tapajos River with respect to methylmercury (MeHg) contamination, using hair mercury as a biological indicator of exposure. Our investigation shows a clear relation between methylmercury contamination and cytogenetic damage in lymphocytes at levels well below 50 micrograms/gram, the level at which initial clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect with increasing MeHg hair level was the impairment of lymphocyte proliferation measured as mitotic index (MI). The relation between mercury concentration in hair and MI suggests that this parameter, an indicator of changes in lymphocytes and their ability to respond to culture conditions, may be an early marker of cytotoxicity and genotoxicity in humans and should be taken into account in the preliminary evaluation of the risks to populations exposed in vivo. This is the first report showing clear cytotoxic effects of long-term exposure to MeHg. Although the results strongly suggest that, under the conditions examined here, MeHg is both a spindle poison and a clastogen, the biological significance of these observations are as yet unknown. A long-term follow-up of these subjects should be undertaken.

A Cellular Mechanism for the Transformation of a Sensory Input into a Motor Command

Abstract: The initiation and control of locomotion largely depend on processing of sensory inputs. The cellular bases of locomotion have been extensively studied in lampreys where reticulospinal (RS) neurons constitute the main descending system activating and controlling the spinal locomotor networks. Ca(2+) imaging and intracellular recordings were used to study the pattern of activation of RS neurons in response to cutaneous stimulation. Pressure applied to the skin evoked a linear input/output relationship in RS neurons until a threshold level, at which a depolarizing plateau was induced, the occurrence of which was associated with the onset of swimming activity in a semi-intact preparation. The occurrence of a depolarizing plateau was abolished by blocking the NMDA receptors that are located on RS cells. Moreover, the depolarizing plateaus were accompanied by a rise in [Ca(2+)](i), and an intracellular injection of the Ca(2+) chelator BAPTA into single RS cells abolished the plateaus, suggesting that the latter are Ca(2+) dependent and rely on intrinsic properties of RS cells. The plateaus were shown to result from the activation of a Ca(2+)-activated nonselective cation current that maintains the cell in a depolarized state. It is concluded that this intrinsic property of the RS neuron is then responsible for the transformation of an incoming sensory signal into a motor command that is then forwarded to the spinal locomotor networks.