Showing papers by "University of Calgary published in 1976"

Plant tissue culture media.

Abstract: Plant tissue culture techniques have become vitally important for pursuing a wide range of fundamental and applied problems in research and development. The techniques encompass a variety of procedures used for specific purposes. The growing of masses of unorganized cells (callus) on agar or in liquid suspension is widely employed in biochemical and growth studies (1-5). The culture of segments of stems, roots, leaves or of callus provides systems to study differentiation, morphogenesis and plant regeneration (6, 7). Shoot apex culture methods leading to plant regeneration have been adopted for plant propagation and production of virusfree stock (8). The culture of anthers and pollen provides new approaches to haploid plant formation (9). Recently the technology has been extended to include the isolation and culture of plant protoplasts which are employed in fusion and somatic cell hybridization (10-13). The development of the various types of tissue culture has been based on empirical approaches, and some of the observations recorded in the literature may not be typical for plant cells. Differences in medium, environment, age, cell origin, and growth rates may explain the behavior of a particular line and need not represent a general characteristic of plant cells in culture. More uniformity in conditions of culture would assist in making data and observations more comparable.

Effect of vegetation on lateral migration of anastomosed channels of a glacier meltwater river

Abstract: A series of experiments were performed on bank materials of anastomosed channels in flood-plain silt deposits in the Alexandra Valley in Banff Park, Alberta, to determine the effect of vegetation roots on bank erodibility and lateral migration of channels. Underground roots from the dense growth of meadow grass and scrub willow provide the reinforcement of bank sediment and a riprap-like protection of channel banks from river erosion. Results from the experiments suggest that in cool environments with aggrading river conditions where overbank deposition of silt, clay, and fine sand dominate the valley fill, vegetation roots are able to rapidly accumulate and decay very slowly, thus affording protection to banks from erosion in deeper parts of the channels. Experiments were performed with a specially designed erosion box, used as a means to simulate natural erosion conditions and measure the influence of vegetation roots in reducing bank erosion. Results indicate that the bank sediment with 16 to 18 percent by volume of roots with a 5-cm root-mat for bank protection, typical of the area, had 20,000 times more resistance to erosion than comparable bank sediment without vegetation. Assuming five severe erosion days per year, potential lateral channel migration would amount to 4.2 cm per year. Such resistance, due to vegetation, accounts for the remarkable stability of channels during the last 2,500 yr in the Alexandra Valley.

Use of calcite twin lamellae to infer differential stress

Abstract: The equation that relates the resolved shear stress coefficient ( S 1 ), differential stress (Δσ), and the critical resolved shear stress ( t c ) necessary to produce twin gliding is t r = S t * Δσ. If we assume an infinite number of possible crystal orientations, it is possible to determine the percentage of grains that has a given value of the resolved shear stress coefficient ( S 1 ) on one, two, or three twin sets. Therefore, if the percentage of grains exhibiting one, two, or three twin sets is known, the differential stress can be determined in terms of the critical resolved shear stress using the above equation. The method has been developed for the case of randomly oriented grains deformed in an irrotational, uniaxial stress field. The method also assumes that all twinning is observable and has occurred in only those orientations where twinning is theoretically possible. Twin gliding has previously been shown to be a mechanism of creep in calcite, and in many cases the method may actually overestimate the magnitude of the differential stress. The validity of this technique of differential stress magnitude determination has been tested by its application to six experimentally deformed samples of Indiana limestone. The calculated differential stresses are within 21 percent of the experimental values for strains of less than 3 to 4 percent. At larger strain values reasonably accurate differential stress values may also be determined, but this requires a greater degree of interpretation. Comparison of samples that contain naturally deformed crystals of both calcite and dolomite suggests that the critical resolved shear stress for dolomite is approximately five times greater than that for calcite.

Mercury Capillary Pressure Curves and the Intepretation of Pore Structure and Capillary Behaviour in Reservoir Rocks

Abstract: Mercury injection and withdrawal capillary pressure curves provide information regarding the efficiency with which a nonwetting phase can be withdrawn from a pore system. Withdrawal (recovery) efficiency varies among samples of differing lithology and can be explained in terms of the geometric aspects of the pore systems, some of which can be interpreted from the capillary pressure curves themselves and others only by direct observation of rocks and resin pore casts. Withdrawal efficiency is defined as the ratio of the volume of mercury withdrawn from a sample at minimum pressure to the volume injected before pressure was reduced. Some features of capillary pressure curves result from experimental procedure and the influences of sample size and shape in conjunction with effects that are peculiar to the external boundary region of the sample. Features which are not typical of an infinite pore system must be recognized before interpretations are made. From experiments on rock samples as well as from theoretical consideration of artificial models it is found that withdrawal efficiency tends to increase with increase in initial saturation. Withdrawal efficiency also increases as throat to pore diameter and volume ratios increase, as the homogeneity of throat and pore sizes increases, and as the number of connections (throats) per pore increases. For a particular sample, withdrawal efficiency is also dependent on saturation history. The initial injection curve combined with the final withdrawal and final reinjection curves for a sample is sufficient to predict withdrawal efficiency from any initial saturation and to construct any desired pair of withdrawal and reinjection curves for intermediate saturations. Experimental determination of the dependency of mercury withdrawal efficiency on saturation history, and the ability to predict withdrawal efficiency for any initial saturation, may be useful in understanding nonwetting phase movements due to capillary effects in hydrocarbon reservoirs.

The electronic structures of tetrahedral oxo-complexes. The nature of the “charge transfer” transitions

Abstract: The electronic structures of MnO−4, MnO2−4, MnO3−4, CrO2−4, CrO3−4, VO3−4, RuO4, RuO−4, RuO2−4, TcO−4 and MoO2−4 have been investigated using the Hartree-Fock-Slater Discrete Variational Method. The calculated ordering of the valence orbitals of all the comlexes is: t1, 4t2, 3a1, 1c, 3t2, with t1 the orbital of highest energy. The calculated single transition energies are in good agreement with experimental values and indicate the uniform assignment: t1 → 2e(v1), 4t2 → 2e(v2). t1 → 5t2(v3), and 4t2 → 5t2(v4). A/D values, calculated from the theory of magnetic circular dichroism (MDC) also support this assignment. Population analyses reveal that all complexes, whether d0, d1 or d2, have d-orbital populations close to those of the corresponding M2+ ions in which two electrons have been removed from the (n + 1)s orbital of M. This is also true of the excited states, such as t1 → 2e and 4t2 → 2e, where a transfer of charge from the ligands to the metal has previously been assumed. It is shown that, instead of a transfer of charge from ligands to metal, electronic excitation consists of a rearrangement of electron density both at the ligands and at the metal.

The Middle-Upper Devonian clastic wedge of the Franklinian Geosyncline

Abstract: Middle-Upper Devonian clastic strata in the Canadian Arctic Islands are present over an area of about 200,000 sq km (75,000 sq mi) and are up to 5,000 m (16,000 ft) thick. The strata comprise a clastic wedge which was deposited in the Franklinian geosyncline prior to Late Devonian - Early Mississippian deformation. The clastic wedge is divided into eleven formations, and six facies are recognized within the strata. The formations and their facies content are: Blackley (submarine fan); Cape de Bray (marine slope); Weatherall (deltaic-marine shelf); Bird Fiord (open-marine shelf and deltaic-marine shelf); Strathcona Fiord (meandering stream); Hecla Bay (braided stream); Fram (meandering stream) (new); Hell Gate (braided stream) (new); Nordstrand Point (meandering stream) (new); Beverley Inlet (meandering stream) (new); and Parry Islands (braided stream, meandering stream and deltaic-marine shelf) (new). Mineralogy, facies distributions, paleocurrent patterns and regional geology all indicate that the source areas of the clastic strata lay to the north and east, and included the Caledonian and Pearya Mountain systems and Precambrian Shield of Greenland. Chert and rock fragments characterize detritus from the Pearya Mountains whereas detritus from the Caledonian Mountains and Precambrian Shield is characterized by a high percentage of monocrystalline quartz. Compositional variations within the clastic wedge indicate that the Pearya Mountains progressively supplied a higher proportion of the detritus throughout wedge development. Paleolatitude estimations, lithologies, fossils and clay mineralogy imply that the clastic wedge was deposited under humid tropical climatic conditions. Lithologic variations in fluvial strata suggest that the climate fluctuated between savanna and very humid. Clastic deposition commenced in the extreme northeast in Eifelian time, and a coastal plain prograded south and west until it covered almost the entire Arctic Islands area by Middle Frasnian. During progradation, submarine fan and marine slope deposits infilled deep basins in the northwest. In Late Frasnian the entire area was uplifted and subjected to erosion. The area was transgressed in latest Frasnian, and a marine shelf was widespread by Early Famennian. In latest Devonian or Early Mississippian the clastic wedge was uplifted and folded to form a "foothills" belt bordering the Pearya Mountains. Sandstone units of delta-front, beach and distributary-channel origin within the Weatherall and Bird Fiord Fms are rated as having the highest potential for petroleum accumulations. The strata may have uranium potential but the meagre data at present available in this regard are not encouraging. End_Page 488------------------------

Diophantine representation of the set of prime numbers

Abstract: (1976). Diophantine Representation of the Set of Prime Numbers. The American Mathematical Monthly: Vol. 83, No. 6, pp. 449-464.

Dynamic single-unit representation of induction motor groups

Abstract: The paper describes a method of representing a group of induction motor loads by a single-unit equivalent. The dynamic performance of the composite group following supply disturbances is examined using the single unit model. The representation employs the induction motor steady state equivalent circuit mad allows for effects of inertia and mechanical load characteristics. Experimental results are presented and compared with corresponding theoretical results using the proposed method as well as classical techniques of analysis. Sudden and gradual supply disturbances are considered, and different load torque-speed characteristics.

An enzyme to degrade lettuce endosperm cell walls. Appearance of a mannanase following phytochrome- and gibberellin-induced germination

Abstract: Lettuce seeds (Lactuca sativa L. cv. Grand Rapids) stimulated to germinate by gibberellin and red light produce large amounts of endo-β-mannanase. This enzyme increases markedly following radicle emergence and is capable of degrading mannose-containing polysaccharides, which are the major components of the endosperm cell wall. Non-germinated seeds contain little enzyme and under conditions where gibberellin- or red light-stimulated germination is prevented (eg. by abscisic acid or prolonged far red light) enzyme levels remain low. Cycloheximide inhibits the increase in enzyme levels when supplied to germinating seeds, but the enzyme once produced is stable in vivo in the presence of this inhibitor for at least 24h. The majority of the extractable mannanase activity is located in the endosperm and we propose that the function of this enzyme is to mobilise the endosperm cell wall polysaccharides as a nutrient source for the growing embryo.

Chromosome analysis on 930 consecutive newborn children using quinacrine fluorescent banding technique

Abstract: Chromosome analysing using quinacrine fluorescence was performed on 930 consecutive newborn infants. The total incidence of major chromosome aberrations including numerical changes of the sex chromosomes, and structural changes of autosomes, was 0.54%. Incidences of XYY (0.4%) and XXY (0.2%) were relatively higher as compared to other studies. About 0.75% of the newborn infants were found to have a variable bright fluorescent band located on the proximal area of the short arm (p11) rather than on the proximal long arm (q11) of chromosome No. 3. Attempts were also made to record the variable fluorescent regions on 7 autosomes and the Y chromosome.

Reaction Time as an Index of Traffic Sign Perception

Abstract: Verbal reaction times to identify and to calssify 20 traffic sign messages were measured under three conditions - sign alone, sign plus visual loading task, and sign plus visual loading task plus visual distraction. Similar trends were found in the three experiments: reaction times were smaller for the classification task than for the identification task, smaller for warning than for regulatory signs, and smaller for verbal than for symbolic messages. Comparison of these reaction time data with on-the-road measures of legibility distance revealed significant correlations. The correlational data add credibility to laboratory measures of reaction times as valid of traffic sign perception. /Author/

Chromosome 21 and the Cell Growth Inhibitory Effect of Human Interferon Preparations

Abstract: INTERFERONS constitute a class of biologically active glycoproteins1–3 which induce a spectrum of physiological changes in living cells, leading to the inhibition of virus replication4, of cell growth in vitro—both normal and tumour cells5,8—and of tumour growth in vivo9–15. The mechanism(s) underlying these effects is unknown. Gressor et al. have suggested that the same molecule in an interferon preparation is responsible for both the antiviral (AV) and cell growth inhibitory (CGI) effect5. This suggestion was based on the observation of a consistent and direct correlation between the two effects in an interferon preparation purified more than a millionfold. Gressor also reported that tumour cells treated with interferon had a lower capacity to form colonies in Agarose and were less tumorigenic when innoculated15, suggesting that the antitumour effect of interferon depended, in part, on the inhibition of tumour cell multiplication which can be demonstrated in vivo. I describe here a genetic approach to ascertain whether the CGI effect of human interferon preparations is mediated by chromosome 21-directed gene(s), known to govern the AV action of interferon16–19. Such an approach, should provide further insight into whether the different effects of interferon are governed by a cluster of genes on chromosome 21 or whether a single genetic locus on chromosome 21 codes for the pleiotropic effects of interferon.

Teaching verbal chains using flow diagrams and texts

Abstract: A flow diagram and text with instructive questions is a common way of teaching sequential chains of some verbal concepts. For example, a psychological principle could be presented in a text (e.g., "antecedents can determine behaviors and behaviors can determine consequences") and in a single flow diagram (e.g., "antecedents -behaviors -consequences"). An accompanying instructive question (e.g., "What determines behavior?") could be used to draw the learner's attention to critical parts of the chain and to provide subsequent learning practice. Such a presentation is usually assumed to form the basis for a multiple-choice recall question (e.g., "What class of events directly initiates behaviorsantecedents or consequences?"), especially if the test questions are related to the previously presented instructive ques-

Mineralogical Review of the Alberta Oil Sand Deposits (Lower Cretaceous, Mannville Group)

Abstract: There are significant variations in the mineralogical components of Lower Cretaceous Mannville Group formations. Source rock is the dominant factor controlling the mineralogical distribution of Mannville Group sediments. The Lower Mannville sediments were derived either 1) from igneous and metamorphic rocks of the Canadian Shield followed by an influx of sediments from a western source, or 2) from sediments covering the Canadian Shield followed by material derived from the Shield itself when the younger sediment cover was removed. Plagioclase, biotite and montmorillonite first appeared and chlorite content increased in the sediments deposited toward the end of Lower Mannville time. Upper Mannville sediments have larger amounts of volcanic rock fragments, plagioclase, potash feldspar, chlorite and montmorillonite throughout Upper Mannville time, which indicates a different source material. Source rock, basin configuration, sea-level movements, depositional environments, diagenesis, and penecontemporaneous and post-burial leaching all affected the mineralogy of the Mannville sediments. Special emphasis in this study has been placed on the identification and abundance of the clay minerals, as these are important not only in a geological context but also with regard to the effective recovery of bitumen from the oil sands.

Analysis of native gibberellins in the internode, nodes, leaves, and inflorescence of developing Avena plants.

Abstract: The native gibberellins (GAs) of various organs of the Avena plant were analyzed by bioassay and gas chromatography-mass spectrometry (GC-MS) after silicic acid partition column chromatography. The major GA of the inflorescence was identified as GA 3 by GC-MS, and this GA also forms the major component of the nodes, p-1 internode, and roots as determined by GLC or chromatography/bioassay. The inflorescence and nodes are the major sources of native GAs, the last two leaves, internode, and roots having significantly lower amounts of GA-like substances. In the internode, less polar GAs predominated at the lag stage of development, whereas by the log and plateau stages, the more polar GAs increased significantly. Since less polar GAs are early in oxidative interconversion sequences, this finding indicates sequential conversion to more polar and probably more active GAs, during log phase growth of the p-1 internode.

Body temperature responses at different ambient temperatures following injections of prostaglandin E1 and noradrenaline into the brain.

Abstract: Since prostaglandins of the E series have been implicated in the production of fever by pyrogens, we have applied them directly to the anterior-hypothalamic preoptic area of uunanesthetized rats at various ambient temperatures. In this paper we have determined accurately the region of the brain of the rat from which temperature responses can be produced by local injection. In addition we present evidence to suggest that the responses to local injections of PGE1 are relatively unaffected by environmental temperatures, whereas those in response to injections of noradrenaline are influenced by ambient temperature. These results are discussed in light of similar findings with respect to the response to pyrogens in that it is relatively unaltered by ambient temperature. This work lends further support to the hypothesis that pyrogens act in the hypothalamus by releasing prostaglandins.

Free radical inactivation of lactate dehydrogenase.

Abstract: SummaryThe enzyme lactate dehydrogenase (LDH) has been irradiated under various conditions to assess the relative contributions of ·H, ·OH, H2O2 and ·O2− to LDH inactivation, and it is concluded that ·OH is the only important inactivating species. Further the effect of the selective free radicals, ·(SCN)2−, ·Br2− and ·I2− on the activity has been studied. In neutral solution, the order of inactivating effectiveness is ·I2− > ·OH > ·Br2− > ·(SCN)2−. At pH 8·6, ·OH and ·Br2− are approximately equal in effectiveness, whereas ·(SCN)2− is the least efficient. The radiation inactivation of LDH is accompanied by a loss of sulphydryl groups, and it is suggested that the primary target for radiation damage in LDH is the active site cysteine-165. Subsequent conformational changes are suggested to account for the apparent loss of coenzyme-binding ability and changes in the enzyme's kinetic parameters. The effect of bound coenzyme (NAD) on radiation-induced inactivation of N2O and air-saturated solutions was also inv...

Phosphatidylinositol kinase and diphosphoinositide kinase of rat kidney cortex: properties and subcellular localization.

Abstract: The properties of phosphatidylinositol kinase and diphosphoinositide kinase from rat kidney cortex were studied. The enzymes were completely Mg2+-dependent. Cutscum detergent activated phosphatidylinositol kinase, but diphosphoinositide kinase was inhibited by all detergents tested. The pH optima were 7.7 for phosphatidylinositol kinase and 6.5 for diphosphoinositide kinase. On subcellular fractionation of kidney-cortex homogenates by differential centriflgation, the distribution of phosphatidylinositol kinase resembled that of the marker enzymes for brush-border, endoplasmic-reticulum and Golgi membranes. Diphosphoinositide kinase distribution resembled that of thiamin pyrophosphatase (assayed in the absence of ATP), diphosphoinositide phosphatase and triphosphoinositide phosphatase. Activities of both kinases were low in purified brush-border fragments. Diphosphoinositide kinase is probably localized in the Golgi complex.

The slash obscures the symbol on prohibitive traffic signs

Abstract: The problem of whether drivers should be told what they can do (permissive message) or what they cannot do (prohibitive message) is discussed as it relates to traffic sign symbols. A widely used version of the prohibitive message (symbol surrounded by a red ring with a slash through the symbol) was found to have limited legibility because the slash obscures the symbol. Two experiments examined the glance legibility of 15 symbols under each of four conditions--slash over symbol, slash under symbol, partial slash, and no slash. The results indicated that the glance legibility of traffic sign symbols is better when no slash or a partial slash is used to convey the prohibitive message. Language: en