Showing papers by "Memorial University of Newfoundland published in 1977"

Perception of impossible limb positions induced by tendon vibration.

Abstract: When the wrist flexor muscle is vibrated and the wrist is passively extended to a position close to its anatomical limit, the hand is felt to be bent to a position about 29 degrees beyond its maximum operating range. The mechanism of position sense must in this case be operating on the basis of extrapolation. Ambiguity of sensed position can occur in this situation. Some subjects, when opposing the vibration-induced contraction of bicepts, report experiencing multiple forearms.

Synaptic connections of the interplexiform cell in the retina of the cat

Abstract: Electron microscopy of Golgi-impregnated material and of well fixed, ultrathin serial sections has revealed the synaptic connections of interplexiform cells in cat retina. In the inner plexiform layer these cells are postsynaptic to amacrine cells and probably presynaptic to both bipolars and amacrines. In the outer plexiform layer they are presynaptic to rod and cone bipolar cells and also pre- and postsynaptic to other interplexiform cell dendrites. The interplexiform cell in cat retina appears to be concerned with feeding back information from the inner plexiform layer to the dendrites of bipolar cells in the outer plexiform layer.

Bounds on the Expectation of a Convex Function of a Random Variable: With Applications to Stochastic Programming

Abstract: This paper is concerned with the determination of tight lower and upper bounds on the expectation of a convex function of a random variable. The classic bounds are those of Jensen and Edmundson-Madansky and were recently generalized by Ben-Tal and Hochman. This paper indicates how still sharper bounds may be generated based on the simple idea of sequentially applying the classic bounds to smaller and smaller subintervals of the range of the random variable. The bounds are applicable in the multivariate case if the random variables are independent. In the dependent case bounds based on the Edmundson-Madansky inequality are not available; however, bounds may be developed using the conditional form of Jensen's inequality. We give some examples to illustrate the geometrical interpretation and the calculations involved in the numerical determination of the new bounds. Special attention is given to the problem of maximizing a nonlinear program that has a stochastic objective function.

Learning as a General Process with an Emphasis on Data from Feeding Experiments

Abstract: General process approaches to learning presuppose that there are learning processes governed by principles general enough to apply to many species in wide varieties of learning situations. A parade example of a general process approach in action is B. F. Skinner’s teaching-machine method. This is a technology of teaching verbal materials to humans largely based on principles derived from conditioning repetitive feeding behaviors in rats and pigeons. Two leaps of faith are implicit: (1) that one can validly extrapolate from pigeons and rats to humans; (2) that one can validly extrapolate from teaching repetitive feeding behaviors to teaching verbal materials. Although Skinner’s approach is an extreme example, most experimental psychologists during the last century have considered learning to be the study of general processes which underlie a great diversity of phenomena.

The oldest macroborers: lower cambrian of labrador.

Abstract: We have discovered numerous borings of Trypanites penetrating skeletons and synsedimentary cemented limestones in archaeocyathid reefs of the Forteau formation in southern Labrador. These are, to date, the oldest known macroborings. The discovery of these structures extends the record of large endolithic organisms 100 million years from the Lower Ordovician to the Lower Cambrian. This immediately postdates the appearance of metazoans with hard parts and confirms that endoliths have played a role in reef formation since the early Cambrian.

On common fixed point theorems

Abstract: The aim of this paper is to extend a recent result of S.A. Husain and V.M. Sehgal [Bull. Austral. Math. Soc. 13 (1975), 261–267]. The condition that the function should be continuous in Husain and Sehgal, op. cit., is replaced by a semicontinuity condition. Moreover, a different proof is given, the last part of which requires no continuity or semicontinuity condition whatsoever.

Gm PHENOTYPES IN AUTOIMMUNE THYROID DISEASE

Abstract: SUMMARY The Gm phenotype Gm f,b or Gm f,n,b was found in all forty patients with Graves' disease studied, contrasted with thirty-five out of forty controls and twenty out of thirty-one patients with thyroiditis. The difference between the two groups with autoimmune thyroid disease was significant. These results suggest that thyroid stimulating antibodies may be allotypically restricted.

Late Quaternary clay-mineral distribution on the eastern continental margin of Canada

Abstract: Clay-mineral determinations have been made on the less than 2 µm size fraction of 116 samples of tills and associated terrestrial sediments, surficial marine sediments, and sediment from deep-sea cores from the eastern continental margin of Canada (Baffin Bay to Nova Scotia). The mineralogy and geographic distribution of clays in surficial sediment largely reflects the distribution of source lithologies and the local origin of the clays; the influence of climate on clay mineralogy is negligible. An illite-chlorite assemblage predominates in sediments from Newfoundland and Labrador and the adjacent inner continental shelf, whereas kaolinite additionally occurs in parts of the Maritime Provinces. In these areas, illite is most abundant in high-grade metamorphic source terrain, chlorite is relatively more common in low-grade metasedimentary and metaigneous terrain, and kaolinite is relatively more common in areas underlain by Carboniferous-Triassic red beds. Marine sediments from Baffin Bay and the outer continental margin of Newfoundland and Labrador contain kaolinite and montmorillonite, in addition to illite and chlorite, which are derived from underlying Mesozoic-Tertiary coastal-plain strata. On the Nova Scotia margin a similar clay-mineral assemblage is derived from both the red beds on land and submerged coastal-plain strata. Three clay assemblages are recognized in Wisconsin sediments on the outer continental margin off Nova Scotia and the Grand Banks. These are (1) red clay turbidites enriched in kaolinite that were transported down the Laurentian Channel; (2) sandier, more montmorillonitic turbidites supplied to the Scotian Rise, partly from glacial outwash and partly from erosion of coastal-plain strata in the heads of submarine canyons; and (3) clay turbidites on the Grand Banks margin that contain more chlorite and less kaolinite than those on the Scotian Rise–Laurentian Fan. These assemblages show that downslope dispersion of sediment by turbidity currents was the dominant process. Holocene reworking of local glacial drift on the shelf is supplying sediment to the outer margin, but at a lesser rate.

The effects of modelling on the contingent praise of mental retardation counsellors.

Abstract: A multiple-baseline design was used to evaluate the effects of a simple modelling procedure on the contingent praise of five counsellors while they conducted hygiene-training sessions in toothbrushing and hand-and-face washing with severely retarded children. After varying numbers of baseline sessions, each counsellor watched a model who conducted a series of toothbrushing sessions, in which he conspicuously praised correct toothbrushing responses and approximations to correct responses. No modelling occurred during hand-and-face washing sessions. As a result of several exposures to the model's performance, levels of response-contingent praise provided by four of the five counsellors during toothbrushing sessions increased sharply over baseline. The levels of counsellor praise showed parallel increases during hand-and-face washing sessions. A two-week followup showed that the levels of praise obtained through modelling were maintained in the model's absence.

Sharp Bounds on the Value of Perfect Information

Abstract: We present sharp bounds on the value of perfect information for static and dynamic simple recourse stochastic programming problems. The bounds are sharper than the available bounds based on Jensen's inequality. The new bounds use some recent extensions of Jensen's upper bound and the Edmundson-Madansky lower bound on the expectation of a concave function of several random variables. Bounds are obtained for nonlinear return functions and linear and strictly increasing concave utility functions for static and dynamic problems. When the random variables are jointly dependent, the Edmundson-Madansky type bound must be replaced by a less sharp "feasible point" bound. Bounds that use constructs from mean-variance analysis are also presented. With independent random variables the calculation of the bounds generally involves several simple univariate numerical integrations and the solution of several similar nonlinear programs. These bounds may be made as sharp as desired with increasing computational effort. The bounds are illustrated on a well-known problem in the literature and on a portfolio selection problem.

Regulation of newly evolved enzymes. III Evolution of the ebg repressor during selection for enhanced lactase activity.

Abstract: The evolution of lactose utilization by lacZ deletion strains of E. coli occurs via mutations in the ebg genes. We show that one kind of mutation in the regulatory gene ebgR results in a repressor which retains the ability to repress synthesis of ebg enzymes, but which permits 4.5-fold more ebg enzyme synthesis during lactose induction than does the wild-type repressor. A comparison between the growth rate of various ebg+ strains on lactose and the amount of ebg enzyme synthesized by these strains shows that the rate of enzyme synthesis permitted by the wild-type repressor is insufficient for growth on lactose as a sole carbon source by a cell with the most active ebg lactase yet isolated. We conclude, therefore, that the evolution of lactose utilization requires both a structural and a regulatory mutation.

How to Brace a One-Story Building

Abstract: This paper describes the economical placing of braces in the walls and ceiling of a rectangular one-story building. First, efficient schemes for bracing the ceiling are shown to correspond to trees...

New palaeomagnetic evidence fails to support rotation of western Newfoundland

Abstract: Palaeomagnetic results from Ordovician to late Precambrian rocks in western Newfoundland are inconsistent with Wegener's hypothesis that the island has rotated 30° anticlockwise. Previous evidence apparently supporting this hypothesis is shown to be inconclusive.

HLA in familial Hodgkin's disease. Results and a new hypothesis;.

Abstract: A familial aggregate of seven cases of Hodgkin's disease (HD) has been investigated by HLA typing. Over 600 people in the immediate population (i.e. about half) have been HLA typed and haplotypes have been obtained for 95% of them. It was expected that the cases would share a particular HLA haplo-type or at least that they would have one or two HLA antigens of the same series in common. However, this was not the case so no simple idea of association of HLA with HD cases was upheld. When antigen frequencies were examined in the whole population it was found that HLA B18 increased progressively in incidence from 0.08 to 0.4 in successive groups of individuals each one more closely related to the HD cases. Similarly the community with the highest incidence of HD also had the highest incidence of B18. Thus B18, which in the world figures carries the highest relative risk, emerged as important in this study. Of four proposed interpretations of the data, we are most interested in the idea that the important HLA association is at a population level rather than at the level of the individual patient. A hypothesis, based on the concept of a “healthy carrier” for the HD agent, explains how such an association might operate. It is possible that B18-linked complement deficiency could be the basis for such a carrier state.

A critique of field methodology for determining fish feeding periodicity

Abstract: Two major criticisms are directed at studies which attempt to determine changes in the feeding intensity of fish in the natural environment over a 24 hour period. A confusing vocabulary in the literature has lead to misinterpretation of data and erroneous conclusions about the diel nature of fish feeding. Workers also tend to conclude that there is variation in stomach content (and by implication feeding rate) over time, without testing observed differences statistically. Large variations in data render such conclusions suspect. This paper attempts to clarify the existing vocabulary by documenting the more commonly used terms and by providing precise definitions of keywords and phrases. A methodology using the analysis of covariance is proposed which establishes statistical criteria upon which more valid inferences about the temporal continuity of fish feeding can be made. Covariant analysis of stomach content data of the longhorn sculpin, Myoxocephalus octodecemspinosus, is used to refute conclusions based on apparent daily feeding activity patterns and exemplifies the need for applying rigorous inferential analysis.

Thyroid Autoimmune Disease in a Large Newfoundland Family: The Influence of HLA

Abstract: Ninety-eight members of a large Newfoundland family, seven of whose members over three generations suffered from Graves' disease, were studied with respect to the mode of transmission of the disease and its association with HLA. Compared to Newfoundland communities of similar size and geographical location, very little consanguinity was documented in this family. The susceptibility to Graves' disease appeared to be inherited as a dominant with a variable degree of expressivity; the degree of expressivity being determined by the female sex. In part of the pedigree, the susceptibility to Graves' disease entered the family with a wife. Three of her offspring who subsequently developed Graves' disease shared with her the haplotype A9, Bw16. Of the three remaining affected family members, two shared the haplotype A1, B8, whereas the third carried the haplotypes Aw32,b8; a9,bw16. Graves' disease could be associated with either of these two haplotypes in the last individual. This study shows that the susceptibility to Graves' disease is inherited associated with HLA and that whereas the disease susceptibility gene for Graves' disease is in linkage disequilibrium with HLA-B8 in Caucasians, it can be randomly associated with other HLA-B antigens.

Ultrastructural studies on the ciliated receptors of the long tentacles of the giant scallop, Placopecten magellanicus (gmelin).

Abstract: The long tentacles of the Giant scallop Placopecten magellanicus (Gmelin) have been examined with light, scanning, and transmission electron microscopy. Three types of ciliated cells have been observed, one of which is located in specialised papillae born on the distal third of the tentacle. There are two separate cell types within the papillae. Type I cells are non-ciliated supporting cells, which form a capsule within which are found the Type II cells. These cells bear up to five cilia at their apices, and it is suggested that these are the receptor cells of the organ. No function has yet been determined for the receptors, but is suggested that they might be mechanoreceptors. A third cell type, Type III cells, occur at the base of the papillae. These cells bear many cilia and also macrocilia. Another ciliated cell type occurs on the proximal two thirds of the tentacle. These cells bear many cilia that are thought to be motile and not sensory.

The role of cytochrome P-450 in the hydroperoxide-catalyzed oxidation of alcohols by rat-liver microsomes.

Abstract: The organic hydroperoxide cumene hydroperoxide is capable of oxidizing ethanol to acetaldehyde in the presence of either catalase, purified cytochrome P-450 or rat liver microsomes. Other hemoproteins like horseradish peroxidase, cytochrome c or hemoglobin were ineffective. In addition to ethanol, higher alcohols like 1-propanol, 1-butanol and 1-pentanol are also oxidized to their corresponding aldehydes to a lesser extent. Other organic hydroxyperoxides will replace cumene hydroperoxide in oxidizing ethanol but less effectively. The cumene-hydroperoxide-dependent ethanol oxidation in microsomes was inhibited partially by cytochrome P-450 inhibitors but was unaffected by catalase inhibitors. Phenobarbital pretreatment of rats increased the specific activity of the cumene-hydroperoxide-dependent ethanol oxidation per mg of microsomes about seven-fold. The evidence suggests that cytochrome P-450 rather than catalase is the enzyme responsible for hydroperoxide-dependent ethanol oxidation. However, when H2O2 is used in place of cumene hydroperoxide, the microsomal ethanol oxidation closely resembles the catalase system.

Some infectious and parasitic diseases in oklahoma raptors

Abstract: Blood films and sera samples from wild Oklahoma raptors (Strigiformes —36 birds, 3 species; Falconiformes—50 birds, 7 species) were examined for hematozoa and tested for serologic antibody response to Newcastle Disease Virus (NDV), encephalitis (EEE and WEE), ornithosis, and influenza. Twenty-nine of 36 (80.5%) Strigiformes and 24 of 50 (48.0%) Falconiformes showed the presence of one or more hematozoa. Serologic testing revealed the serum of one adult male red-tailed hawk positive for antibody to NDV and one additional adult male red-tailed hawk positive for antibody to type-A influenza.

Effects of orienting task, spacing of repetitions, and list context on judgments of frequency

Abstract: Subjects were given an unexpected frequency judgment test following a list of words in which items were presented either two, three, and five times or three, five, and seven times, with a spacing of 0, 2, 16, or 32 items between repetitions. During list presentation, they either rated the imagery value of each word or made continuous frequency estimates. Postlist frequency judgments of words presented three and five times were higher for the list containing words of Frequency 7, and judgments were also higher following the imagery rating task. Continuous judgments were unaffected by the list context and showed different effects of spacing than postlist judgments. The results provide support for the operation of response bias factors in the frequency judgment task and are relevant to theoretical interpretations of the spacing effect.