Showing papers by "Laval University published in 1985"

Bilingualism and Special Education: Issues in Assessment and Pedagogy

Abstract: missing); some questions have no results presented; most results are not subjected to statistical tests but are merely presented as frequencies of replies; and where statistical tests are reported, the details are often too sketchy to judge the validity of the procedure. Many of the studies seem to have been executed and analysed by the author’s students, which may account for some of the reporting and validity problems. Still, the patterns of results are intriguing and should prompt further, more controlled research into these issues. Also, where differences are exceptionally large, statistical tests are probably unnecessary to confirm the pattern that is discerned. Interpersonal communication scholars may therefore find the studies useful in revealing the social meanings ascribed to certain nonverbal behaviours and the mediating effects of perceived context and demographics on those interpretations. Practitioners should likewise discern many valuable conclusions about successful and unsuccessful interview behaviours.

A laminar analysis of the number of round‐asymmetrical and flat‐symmetrical synapses on spines, dendritic trunks, and cell bodies in area 17 of the cat

Abstract: The number of synapses per unit volume of tissue (NV) has been estimated in individual laminae of the binocular and monocular regions of area 17 in six adult cats by using a method of size-frequency distribution. Separate estimates were obtained for RA synapses (containing round vesicles associated with asymmetric membrane differentiations) and for FS synapses (containing flat vesicles associated with symmetric membrane differentiations). For the total cortical thickness, the NV of all synapses is not statistically different between binocular (286 million per mm1(3] and monocular (281 million) regions, nor is it different between the two regions for any of the laminae. Eighty-four percent of synapses are of the RA type. Of those, 79% are found on dendritic spines, 21% on dendritic trunks, 0.1% on somata. FS synapses represent 16% of the total, with 31% of them on spines, 62% on dendritic trunks, and 7% on somata. The ratio of RA to FS synapses is kept relatively constant throughout the layers. A two-way analysis of variance shows no difference in the NV of either RA or FS synapses in the two regions nor in the NV or RA synapses between cats. It does, however, clearly demonstrate (p less than 0.001) interindividual differences for FS synapses. These variations between individual cats may be due to differences in age, breed, or environmental factors. In contrast to the relative uniformity of the NV of synapses between regions, the number of each type under 1 mm2 of cortical surface is 33% higher in the binocular region. This is due mainly to the greater thickness of the binocular region.

Evidence for a regional component of body fatness in the association with serum lipids in men and women

Abstract: Four hundred and seventy-two subjects (234 women and 238 men), 18 to 50 years of age, participated in percent body fat determination from underwater weighing, assessment of 6 subcutaneous skinfold thicknesses, and a 12-hour fast blood sampling for measurement of serum triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), total cholesterol (CHOL), and HDL-C/CHOL ratio Even though women were significantly fatter than men, they had lower TG, CHOL, and higher values of HDL-C/CHOL ratio Correlational and variance analyses showed that body fatness seemed to be more closely associated with serum lipids in men than in women Moreover, the relationship between each skinfold and serum lipids indicated that subscapular and abdominal fat depots are more closely associated with serum lipids than other fat depots in men In women, correlations were lower and regional differences attenuated Furthermore, the regional trend observed in men remained significant after correction for concomitant variables such as age, cigarette smoking, habitual energy intake and energy expenditure, maximal aerobic power, and alcohol consumption However, no effect of increasing body fatness was noted on HDL-C levels in women Results of this study suggest that measurement of subscapular and abdominal fat should be considered when interpreting the blood lipid profile, particularly in males A higher percentage of fat must be present in women than in men to observe alterations in serum lipids

Human skeletal muscle fiber type alteration with high-intensity intermittent training

Abstract: The response of muscle fiber type proportions and fiber areas to 15 weeks of strenuous high-intensity intermittent training was investigated in twenty-four carefully ascertained sedentary (14 women and 10 men) and 10 control (4 women and 6 men) subjects. The supervised training program consisted mainly of series of supramaximal exercise lasting 15 s to 90 s on a cycle ergometer. Proportions of muscle fiber type and areas of the fibers were determined from a biopsy of the vastus lateralis before and after the training program. No significant change was observed for any of the histochemical charactertics in the control group. Training significantly increased the proportion of type I and decreased type IIb fibers, the proportion of type IIa remained unchanged. Areas of type I and IIb fibers increased significantly with training. These results suggest that high-intensity intermittent training in humans may alter the proportion of type I and the area of type I and IIb fibers and in consequence that fiber type composition in human vastus lateralis muscle is not determined solely by genetic factors.

Late Holocene deforestation and tree regeneration in the forest–tundra of Québec

Abstract: Reconstructions of climate in the Holocene rely heavily on palaeoclimatic indicators such as altitudinal and latitudinal tree-line movements1 inferred either from direct (macrofossil), or indirect (pollen), evidence of sites more or less distant from the present treelines2–8. Long-term trends in tree regeneration on well-drained sites of the forest–tundra—the transition zone between the Boreal forest and the Arctic tundra zones—may also be used as ecological indicators of Holocene climatic changes. Charcoal found in soils of treeless or forest vegetation in the transition zone indicates respectively, failure or success in the post-fire regeneration of trees; as regeneration is influenced by climate, radiocarbon-dated charcoal can be used as a record of palaeoclimate. We suggest here that the widespread occurrence of treeless sites is the result of late Holocene deforestation involving climate–fire interactions and that disjunct lichen-forest sites are the outcome of successful regeneration sometime during the last 1,000 yr. This climatically induced process is acting at the site and the species levels, south of the present tree line.

Distribution of neuropeptide Y immunoreactivity in the basal forebrain and upper brainstem of the squirrel monkey (saimiri sciureus)

Abstract: The distribution of neuropeptide Y (NPY) immunoreactivity in the brain of the squirrel monkey (Saimiri sciureus) was studied by means of the indirect immunofluorescence, peroxidase-antiperoxidase, and avidin-biotin-complex methods. The antiserum used was raised in rabbits and did not show any significant crossreactivity with related peptides including peptide YY and avian pancreatic polypeptide. In the upper brainstem of the squirrel monkey a dense NPY-immunoreactive terminal field is seen in lateral parabrachial area, locus coeruleus, and interpeduncular nucleus. A small group of NPY-immunoreactive cell bodies is present in the lateral habenula and a moderate number of NPY-immunoreactive fibers occurs in periaqueductal gray and nucleus raphe pallidus. The substantia nigra (SN) appears mostly devoid of NPY immunoreactivity whereas the ventral tegmental area contains a few reactive fibers. In the hypothalamus the medial preoptic area as well as the arcuate and paraventricular nuclei receive a strikingly dense NPY innervation. In addition, numerous NPY-positive cell bodies are found within the dorsomedial half of the supraoptic nucleus but very few are seen in paraventricular nucleus. A large number of NPY-immunoreactive cell bodies is also present in arcuate nucleus. In the basal telencephalon NPY-immunoreactive cells abound mostly in striatum, but some are also found in the amygdala (particularly basal, central, and lateral amygdaloid nuclei), the claustrum, and in the bed nucleus of the stria terminalis. Intensely reactive network of NPY-immunoreactive fibers is also present in all of these structures. In striatum, the numerous, fine and nonvaricose NPY-immunoreactive fibers, as well as the NPY-positive cell bodies, are slightly more abundant in caudate nucleus than in putamen. The globus pallidus (GP) is mostly devoid of NPY-immunoreactive fibers and terminals. The fact that the two major recipient structures of striatal outflow (SN and GP) do not receive significant NPY input suggests that the striatal NPY-containing neurons are intrinsically organized.

Reflective subcategories, localizations and factorizationa systems

Abstract: This work is a detailed analysis of the relationship between reflective subcategories of a category and factorization systems supported by the category.

Secular climate change in old-growth tree-line vegetation of northern Quebec

Abstract: The climate of the Northern Hemisphere changed during recent centuries, as shown by the Little Ice Age episode1 and the warming trend of the past 100 years2,3. The ecological impacts of these changes have yet to be evaluated in several terrestrial ecosystems, incorporating direct evidence such as detailed botanical field observations4. We report here results of the analysis of a ∼600-year response of a lichen–spruce woodland to this long-term trend, which are thought to be the first extensive illustration of these impacts in the Subarctic. It suggests that tree-line vegetation is in a dynamic equilibrium with climate in the absence of other external disturbances; this is emphasized by spruce reaction through phenotypic adaptation—a shift from stunted individuals (krummholz) to normal trees (forest)—and differential regeneration. This study produces evidence that marginal northern forests can persist through time and that successional processes, in the absence of fire, perpetuate the original lichen–spruce facies. The longest tree-ring chronology (AD 1398–1982) yet available in eastern North America was constructed from living and dead spruces found in the lichen woodland of our study.

Physiological action of humic substances on microbial cells

Abstract: By incorporating molecular weight fractions of humic acids of various origins into selective substrates designed for the enumeration of physiological groups of microorganisms, it was found that the presence of humic acids at concentrations of up to 30mgl −1 normally resulted in increased numbers of soil microbes active within a particular physiological group. Observed increases could be as much as 2000-fold. Microbes in an organic humus-rich soil were more stimulated by humic substances than organisms from a sandy soil. In certain microbes humic substances appeared to induce a change in metabolism, allowing the organisms to proliferate on substrates which previously they could not utilize. Indications were obtained that within the 10–30 mgl −1 concentration range lower molecular weight humic fractions (approx. 5500 dallons) were more effective than higher molecular weight material. At higher concentrations the reverse was sometimes noticed. Similarly, fulvic acids at concentrations of up to approximately 50mgl −1 would appear to have a more pronounced physiological effect than humic acids, whereas the latter might be more effective at higher concentrations. The response of certain physiological groups to humic products of natural origin appeared to be comparable to that of surfactants such as Tween and Brij. This would suggest that the physiological action of humic substances is, at least partly, the result of their surface activity, making the membrane one of the prime targets of the physiological action of humics on living cells.

The variable manifestations of dysplasia epiphysealis hemimelica.

Abstract: Dysplasia epiphysealis hemimelica (DEH) is an osteocartilaginous overgrowth involving one or multiple epiphyses or ossification centers, usually in a lower extremity on one side of the body. Characteristically the involvement is hemimelic i.e. either the medial or lateral part of the ossification center is involved. We have studied 24 patients with DEH and are adding 15 new cases to the literature. Because of the variable manifestations of the dysplasia and its different degrees of involvement in the affected children, we have subdivided it into localized, classical and generalized forms. In the generalized form, there is involvement of a whole lower extremity from the pelvis to the foot, and some of these patients show megaepiphyses with enlargement of a whole epiphyseal center, not only its medial or lateral part. We have also described and illustrated other special features of the dysplasia especially the advanced bone age and the metaphyseal and growth plate involvement.

In situ twilight grazing rhythm during diel vertical migrations of a scattering layer of Calanus finmarchicus1

Abstract: A scattering layer of Calanusjnmarchicus was sampled every 90 min during 48 h in the lower St. Lawrence estuary. Grazing activity (phytoplankton pigments in the gut) and the percentage of recently and nonrecently fed copepods (from observation of food in the gut) were monitored in two strata (O-30 m and 30-100 m). Phytoplankton was restricted to the upper stratum. A bimodal twilight grazing rhythm was observed: the first feeding period, in the upper stratum, begins after sunset; it is followed by the “midnight sinking” in the deeper stratum (2-3 h), during which the gut content is evacuated; after this, the animals return to the upper stratum for a second meal, before the dawn descent. In both migrations, there was a dynamic interchange of individuals between the two strata, which masked the fact that all the copepods migrated to the upper stratum and that a dawn rise actually happened. The feeding time in the warmer surface water was very short. Feeding ceased rapidly even if phytoplankton concentration was low. A large increase in the number of migrants did not change the feeding patterns. Results support the hypothesis that the behavior of C. jinmarchicus during the central phase of vertical migrations in late summer is closely linked to an in situ grazing rhythm.

Defect in vitamin B12 release from lysosomes: newly described inborn error of vitamin B12 metabolism.

Abstract: Cultured diploid fibroblasts from a patient with a previously undescribed inborn error of cobalamin metabolism accumulate unmetabolized, nonprotein-bound vitamin B12 in lysosomes. These cells are able to endocytose the transcobalamin II-B12 complex and to release B12 from transcobalamin II. The freed vitamin B12 is not released from lysosomes into the cytoplasm of the cell. This suggests that there is a specific lysosomal transport mechanism for vitamin B12 in the human.

Efficiency of immobilized hyperconcentrated algae for ammonium and orthophosphate removal from wastewaters

Abstract: Hyperconcentrated microalgae cultures (up to 3,29 g dry weight/L) were immobilized in kappa-carrageenan beads. It appears that entrapped algae are able to remove efficiently nitrogen and phosphorus from urban secondary effluent and then perform a tertiary wastewater treatment.

An empirical assessment of stereological formulae applied to the counting of synaptic disks in the cerebral cortex

Abstract: Known quantities of test objects approximating the parameters of cortical synapses were embedded in known volumes of a transparent embedding medium The material was cut in slabs of appropriate thickness The mean trace length (d) of the profiles of the test objects was measured and the number of profiles per unit area (NA) was calculated Various stereological formulae were applied to these data to determine the number of test objects per unit volume (NV) For large numbers of those test objects most closely approximating the parameters of cortical synapses, the formula NV = NA/d and the DeHoff and Rhines formula ('61) for polydispersed circular disks NV = 8NAZ/ pi 2 (where Z is the mean of the reciprocals of the trace lengths) gave accurate results (error less than or equal to 5%) Other popular formulae and procedures were not as accurate and underestimated their number by as much as 32%

Effects of nectar concentration on butterfly feeding: measured feeding rates for Thymelicus lineola (Lepidoptera: Hesperiidae) and a general feeding model for adult Lepidoptera.

Abstract: Field observations of the adult European skipper, Thymelicus lineola (Ochs), feeding on concentrated nectars (40-65% sucrose) from a variety of flower species led us to question recent literature stating that butterflies feed primarily, and most effectively, on dilute nectars. Rate of sucrose solution intake, volume consumed and feeding duration were measured for males and females at 25 and 35°C under laboratory conditions. As sucrose concentration increased, the volume of solution ingested per meal first increased and then decreased gradually, while sucrose intake was highest at concentrations ≧40%. Females fed more than males at all concentrations >10% while temperature had no significant effect on meal size. Feeding duration increased with concentration, was shorter at 35 than at 25°C, and was longer for females than males.The rate of volume intake decreased as concentration incresed, but not nearly as rapidly as predicted by earlier models. Rates did not differ between the sexes but were faster at 35 than 25°C. This increase was contributed to equally by a reduction in viscosity and an increase in power output of the cibarial pump. The form of the relations was similar, with maximum rate of sucrose intake occurring at 40% sucrose.A new mathematical model was developed to describe the rate - concentration relation based on the Hagen-Poiseuille equation for laminar fluid flow through pipes. Our model differs from previous models principally in that the power output of the insect's cibarial pump remains relatively constant while the pressure drop created by the pump to induce suction is highly variable. This change results in a very different feeding rate - sucrose concentration function with the optimal rate of sucrose intake at a concentration of approximately 40%. The model indicates that the same relation should hold for a wide range of proboscis shape and size and type of suction pump, and should therefore be applicable to all other nectar feeders with sucking mouth parts. Independent verifications of the model were carried out by measuring the rate of uptake of sucrose solutions of the adult common armyworm, Pseudaletia unipuncta (Haw.), and of human subjects using a volumetric pipette, both of which gave an excellent fit.Nectar concentrations which correspond to optimal rates of sucrose intake should be highly preferred by insects with high feeding costs, those which are time-limited, or which are very vulnerable while feeding. High transport costs and severe water stress may shift preferences to higher and lower concentrations respectively.

Shearing interferometer for phase shifting interferometry with polarization phase shifter.

Abstract: A cyclic interferometer can be used for both lateral and radial shearing. Being common-path this interferometer is quite stable. The use of a cyclic shear interferometer for phase shifting interferometry is discussed. The phase shifting is provided here by polarization techniques. Some useful cyclic phase shifting interferometer arrangements are discussed, and the working of a polarization phase shifting cyclic shear interferometer is demonstrated.

Accuracy of the judgment of facial expression of emotions as a function of sex and level of education

Abstract: The purpose of this study is to examine the recognition of facial expressions of six emotions as a function of sex and level of education (high school, college, university) of the subjects. Three hundred French-speaking citizens of Quebec had to judge which emotion was expressed in various facial stimuli presented on slides. Results show that overall, the recognition of emotions was very good. However, there were significant and strong differences between emotions and sex and levels of education did not have strong effects on the results.