Showing papers by "Dalhousie University published in 1976"
TL;DR: Initial results indicate the complexity of diel feeding patterns of marine copepod patterns, with either a single night peak or dawn and dusk peaks for adult copepods.
475 citations
TL;DR: A bibliographic list of 403 articles dealing specifically with conditioned taste aversions from 1950 to 1975 is provided in this article, where references are classified according to six major categories in a topical index.
Abstract: A bibliographic list of 403 articles dealing specifically with conditioned taste aversions from 1950–1975 is provided. In addition, the references are classified according to six major categories in a topical index. The major categories are Parameters of Conditioning, Physiological Manipulations, Pharmacological Interventions, Methodology, Comparative, and General Information. References were obtained from individual journals in psychology, physiology, pharmacology, and animal behavior and were supplemented and extended byPsychological Abstracts. A final source of references was provided by individual researchers who contributed preprints and reprints.
274 citations
TL;DR: In this article, a new gas chromatographic method was developed for the measurement of nitrous oxide (N2O) in seawater, which takes 15 min for the analysis in a sample of 640 ml seawater.
234 citations
TL;DR: In this article, new trace element analyses have been made on the composite Canadian Precambrian shield samples reported in 1967 and the overall mean abundance of Cr has been revised to 35 ppm (from 99).
208 citations
TL;DR: The SAI has concurrent validity with respect to sexual experience, activity, and satisfaction, and discriminates between clinical and normal populations, and possesses exceptional internal consistency.
Abstract: This report describes the development of a self-report Sexual Arousability Inventory (SAI) for women. Sexual arousability was defined as the sum of a respondent's ratings of 28 erotic experience along a 7-point Likert arousal dimension. Multiple-regression and factor analyses were used to select valid items from a 131-item pool and build in factorial purity. The SAI has concurrent validity with respect to sexual experience, activity, and satisfaction, and discriminates between clinical and normal populations. In addition, the SAI is easy to administer and score, may be used with single, married, or lesbian women, is available with norms and in alternate forms, and possesses exceptional internal consistency. Although the SAI was designed primarily for clinical use, the construct it measures may have theoretical significance in future research.
207 citations
TL;DR: In a study area in Nova Scotia, Canada, abundance of the lobster Homarus americanus decreased by nearly 50% in 14 years.
Abstract: In a study area in Nova Scotia, Canada, abundance of the lobster Homarus americanus decreased by nearly 50% in 14 years. The lobster is a major predator of sea urchins, and during the past 6 years the sea urchin Strongylocentrotus droebachiensis has destroyed 70% of the beds of Laminaria spp. in the area. Implications for management are discussed.
183 citations
TL;DR: Differences indicate the SPH'ASE 7.4 is a different enzyme protein from sph'ase 5.0, suggesting a role related to the specific functions of this organ or to the need for a more stringent control of sphingomyelin catabolism in brain as compared to other organs.
166 citations
157 citations
TL;DR: Evidence that cortical units retain plasticity long after the end of this period of deprivation is obtained, which shows that ocular alignment as well as cortical unit properties can remain plastic in the adult.
Abstract: Evidence that there is a critical period during which response characteristics of neurons in visual cortex of the cat may be influenced has been provided in several studies, which suggest that the period of influence is restricted to the first few months of life. Using a somewhat different experimental procedure, we have obtained evidence that cortical units retain plasticity long after the end of this period has passed. In our procedure prolonged visual deprivation was followed by exposure in a normal visual environment. The animals were maintained throughout the first year of life either in total darkness or in an enclosure illuminated intermittently by a strobe light. Following the period of deprivation, electrophysiologic recordings were taken from some of these animals. The remaining cats were permitted 6–12 months in a normally-illuminated environment prior to recording. Cats of the same age reared from birth in a normally lit environment were also recorded.
138 citations
TL;DR: Cats were reared in a stroboscopically illuminated environment, which deprived them of expereience with visual movement but allowed them form vision, and neurons of the visual cortex displayed normal orientation selectivity but direction selectivity was virtually abolished.
Abstract: Cats were reared in a stroboscopically illuminated environment, which deprived them of expereience with visual movement but allowed them form vision. In these cats, neurons of the visual cortex displayed normal orientation selectivity, but direction selectivity was virtually abolished. The effect remained unaltered by long periods of normal visual exposure.
128 citations
TL;DR: With increase of time since kelp disappearance, the sea urchins showed decreased growth rate, reduced gonad size, but an increase in numbers resulting from high recruitment rates in the first two years after kelp bed destruction.
Abstract: In St. Margaret's Bay, Nova Scotia, Canada, there are large areas in which sea urchins (Strongylocentrotus droebachiensis) have eliminated beds of kelp (Laminaria spp.). Sites were identified where destruction of kelp beds had taken place 1, 2, 3, 3.5 and 4 years ago. With increase of time since kelp disappearance, the sea urchins showed decreased growth rate, reduced gonad size, but an increase in numbers resulting from high recruitment rates in the first two years after kelp bed destruction. These sea urchin populations, by their browsing, effectively prevent the regeneration of kelp. There is, as yet, no evidence of the sea urchin populations being starved out to allow the kelp to return.
TL;DR: A longitudinal study of the development of the visual acuity of young kittens was made using a behavioural method similar in principle to that employed by Lashley many years ago for his studies of pattern vision in the rat.
TL;DR: A conspicuous latitudinal trend was found: the clustering of both landward and seaward boundaries increased with increasing latitude, and evidence that between-species competition influences the locations of zone boundaries was obtained.
Abstract: Zonation patterns of salt marsh vegetation were examined at latitudes ranging from 44°40′N at Halifax, Nova Scotia, to 58°50′N at Churchill, Manitoba. It was found that in all areas examined the landward boundaries of the species' zones were more nearly coincident (i.e., more clustered) than their seaward boundaries. A conspicuous latitudinal trend was found: the clustering of both landward and seaward boundaries increased with increasing latitude. Evidence that between-species competition influences the locations of zone boundaries was also obtained. Possible implications of the results in terms of a relationship between intrapopulation polymorphism and latitude are discussed.
TL;DR: Partial sequence analyses of 16S ribosomal RNAs of blue-green algae and chloroplasts reveal that blue- green algae are typically prokaryotic and related to the bacilli, and that euglenoid and red algal chloroplast may have arisen independently.
Abstract: Partial sequence analyses of 16S ribosomal RNAs of blue-green algae and chloroplasts reveal that blue-green algae are typically prokaryotic and related to the bacilli, that red algal chloroplasts are probably of blue-green algal origin, and that euglenoid and red algal chloroplasts may have arisen independently.
29 Jan 1976
TL;DR: In this article, the transition from strongly reflected surging to dissipative plunging breakers on a relatively steep plane beach (1:8) has been studied and it has been shown that the run-up and offshore variation of sea surface elevation of surging waves are well predicted by linear theory.
Abstract: A laboratory and theoretical study of the transition from strongly reflected surging to dissipative plunging breakers on a relatively steep plane beach (1:8) has revealed the following: (1) The run-up and offshore variation of sea surface elevation of surging waves are well predicted by linear theory. (2) The fluctuating part of the run-up (related to the amplitude of the reflected incident wave) reaches a maximum value; a further increase in incident progressive wave energy results in increased dissipation. (3) Subharmonic edge waves (the growing instabilities of surging waves) are driven primarily by the swash motion, which does not increase with increasing incident breaking wave height. However, the turbulence accompanying incident wave breaking, and the effective eddy viscosity, rapidly increases with increasing breaker height. As a result, subharmonic resonances do not occur with spilling or steep plunging waves; very strong viscous effects suppress the nonlinear instabilities. (4) edge waves generated by a surging incident wave can be suppressed by superimposing an additional breaking wave of different frequency on the incident wave field. Thus, any excited edge waves are likely to have length scales at least the order of a surf zone width.
TL;DR: In this paper, it was shown that every square matrix over a field, with determinant ± 1, is the product of not more than four involutions, and that the number of involutions is fixed.
TL;DR: Data suggest that eating is not a terminal “consummatory” component of preying as a food-getting response, and Hunger may be seen as a potentiator of a predatory tendency which takes precedence over food consumption.
TL;DR: It was concluded that rats learn the relationship between responding and environmental events and that such learning strongly influences subsequent learning.
TL;DR: In this paper, a two-dimensional anisotropic correlation model has been derived using a simple autoregressive scheme, and much of the direction-dependent variability of observed statistics is resolved.
Abstract: Covariance models used in the data assimilation step of operational forecasting generally assume isotropy of height field correlations on constant pressure levels. Because of the evidence that this assumption is a significant source of forecast error, especially In regions of low density data, a two-dimensional anisotropic correlation model has been derived. Using a simple autoregressive scheme, cumbersome extension of the modeling problem has been avoided and much of the direction-dependent variability of observed statistics is resolved. Compared to deviations of observed correlation values around the best fitting isotropic model, the residual variance has been reduced by 56&%.
TL;DR: The pistil of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) is comprised of two fused carpels and the stigma is bilobed, papillose, and at maturity is covered with a sticky exudate.
Abstract: The pistil of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) is comprised of two fused carpels. The stigma is bilobed, papillose, and at maturity is covered with a sticky exudate. The style is solid. Both stigma and style are made up of four tissue elements—epidermis, cortex, vascular, and transmitting tissue. Transmitting tissue in this species is chlorophyllous. Transmitting cells have thin primary walls and are separated by massive deposits of denselystaining amorphous material. The cells contain numerous mitochondria, dictyosomes, RER, amyloplasts, ribosomes, as well as crystal-containing microbodies and myelin-like formations. Observations are discussed in relation to other reports dealing with similar cell populations.
TL;DR: In this article, the effects of lateral inhomogeneities in structure are examined using two-dimensional finite element models, and the results demonstrate that the topographic and geologic corrections are as large as ±25 per cent of the homogeneous strain tide for some of the strainmenter sites examined.
Abstract: In Beaumont and Berger (1975), strain observations from seven sites in the continental United States were analyzed and compared with the homogeneous tides predicted for a radially stratified earth including the effects of ocean-tide loading. In this work the effects of lateral inhomogeneities in structure are examined using two- and three-dimensional finite element models. The results demonstrate that the topographic and geologic corrections are as large as ±25 per cent of the homogeneous strain tide for some of the strainmenter sites examined. Cavity effects are normally less than 5 per cent unless the strainmeters are installed transversely in tunnels. Contour plots of the topographic effects show that they may exceed ±50 per cent of the homogeneous strain in extreme cases. It is concluded from an error analysis that a theoretical model including local perturbations due to lateral inhomogeneities as well as the load and earth tides explains the observations. However, the errors in the observations, and uncertainties in our knowledge of the deep ocean tides in particular, prevent strain observations from providing useful measures of whole earth elastic properties (Love numbers) or anelasticity. In addition to earth tides, the results demonstrate that secular strain, in situ stress, and seismic strain must all be corrected for site effects.
TL;DR: In contrast to a recent report, tilt after-effects induced on oblique stimuli were found to be similar in magnitude and direction to those observed on stimuli that were vertical or horizontal.
TL;DR: In this paper, the effect of He(23S) with CS2 produces relatively strong emission from the CS2−X2∑+ and CS(A1II−X1∑+) systems.
TL;DR: In this paper, four self-referred adult male homosexuals were provided with therapy to increase their level of heterosexual responsiveness, including 40 sessions of orgasmic reconditioning using both visual and fantasied stimuli, in counterbalanced treatment sequences.
TL;DR: The 3α- and 12α-hydroxysteroid dehydrogenase activities, although differing in cofactor requirements cannot be distinguished by their appearance in the growth curve, their mobility on disc gel electrophoresis, elution volume on passage through Sephadex G-200 or heat inactivation studies, appear to be constitutive rather than inducible.
TL;DR: The lipid composition of chick brain and sciatic nerve was determined during development and it was confirmed that the addition of CaCl2 to solvents during the extraction of lipids from brain results in much higher yields of diphosphoinositides particularly from unmyelinated embryo brain.
Abstract: — The lipid composition of chick brain and sciatic nerve was determined during development. It was confirmed that the addition of CaCl2 to solvents during the extraction of lipids from brain results in much higher yields of diphosphoinositides particularly from unmyelinated embryo brain. Unlike the earlier report for rat brain, the recovery of triphosphoinositides was also Substantially increased. The amount of CaCl2, required to achieve optimal recoveries decreased with increasing age and addition of more than this optimal amount depressed the yields of polyphosphoinositides, particularly triphosphoinositides. CaCl2, addition did not improve the yield of diphosphoinositides from sciatic nerve of any age but drastically reduced recovery of triphosphoinositidcs. Differenccs in the effect of CaCl2 were not the result of variation in the tissue concentrations of calcium or magnesium.
The lipid composition of sciatic nerve closely reflected that of the myelin. Both polyphosphoinositides were absent initially and their accumulation paralleled that of cerebrosides and sulfatides. The concentration of diphosphoinositides remained constant after the period of most active myelination while triphosphoinositides and the galactolipids continued to increase suggesting maturational changes in the myelin composition. The pattern of deposition in chick brain was similar except for the much greater contribution of non-myelin structures. Both polyphosphoinositides were present in equimolar amounts in pre-myelination embryonic tissue. The concentration of diphosphoinositides increased during active myelination only while triphosphoinositides continued to increase thereafter.
TL;DR: When uniform methods of collection and analysis are employed, particulate organic carbon (POC) distributions in the South Atlantic, South Pacific, and North Pacific oceans are roughly comparable as discussed by the authors.
TL;DR: The H-2-blocking antihistamine metiamide was used to treat 14 episodes of bleeding from the stomach or duodenum in eleven patients and seems to be a safe and highly effective agent in the control of bleeding due to erosive gastritis.
TL;DR: In this paper, the compositional dependence of the Neel temperature has been studied, from data derived by different techniques and by various authors, for 30 austenitic stainless steels or special Fe-Cr-Ni alloys whose compositions fall near the range of the AISI 300 series.