Showing papers by "Carleton University published in 1973"
TL;DR: Glutamine synthetase was purified to apparent homogeneity from the shoots of light-grown pea seedlings and was found to be quite unstable, but could be partially stabilized by the addition of divalent cation.
304 citations
TL;DR: Together, the results imply that kindling establishes a lasting trace which is both transynaptic and widespread, kindling from a second location establishes a second trace utilizing parts of the existing trace, a series of convulsions leaves a less durable after-effect with a decay time of about 2 weeks and which interferes with various aspects of seizure activity, and the trace which activates the convulsion is less susceptible to interference from the after- effect.
178 citations
TL;DR: In this article, cyclic voltammetric investigations of copper electrodes in aqueous KOH were carried out systematically, and nine peaks on the voltammograms were analysed as stated in the Conclusions section.
148 citations
TL;DR: The capacity of a growing leaf blade of Cucurbita pepo L. to import 14C-labelled photoassimilate is lost in a basipetal direction and export capacity follows immediately the loss of import capacity, at least in the lamina base.
Abstract: The capacity of a growing leaf blade of Cucurbita pepo L. to import 14C-labelled photoassimilate is lost in a basipetal direction. Import into the lamina tip stops when the blade is 10% expanded. Development of the leaf progresses linearly with time and the lamina base stops importing when the blade is 45% expanded. Export capacity also develops basipetally and follows immediately the loss of import capacity, at least in the lamina base. The small amount of material initially exported from the leaf tip is redistributed to the still-importing leaf base, delaying export from the lamina until the blade is 35% expanded. Loss of import capacity by the petiole is both basipetal and dorsoventral. The proximal, adaxial portion of the petiole is the last region to cease importing 14C. Leaves of Beta vulgaris L. and Nicotiana tabacum L. also lose import capacity in a basipetal direction.
92 citations
TL;DR: This study describes changes in the fine structure of these cells during lateral root initiation, and follows the differentiation sequence between parent endodermal cells and their derivatives, the epidermal and rootcap cells of the young lateral.
Abstract: 1.
Lateral roots in corn are initiated in regions of the main root where the endodermal and pericycle cells are highly differentiated and have secondary walls. This study describes changes in the fine structure of these cells during lateral root initiation, and follows the differentiation sequence between parent endodermal cells and their derivatives, the epidermal and rootcap cells of the young lateral.
2.
Possible effects of the presence of young lateral root primordia on the control of ion diffusion across roots are discussed.
63 citations
TL;DR: In view of recent theoretical interest in the possibility of a light scalar boson ϕ and possible methods for detecting it, the authors discussed some of its properties and proposed a general method of determining the mass of a particle from the energy of its decay products alone.
Abstract: In view of recent theoretical interest in the possibility of a light scalar boson ϕ we discuss some of its properties and possible methods for detecting it. Cross sections for its production are typically 10 −8 of competing processes, with the possible exception of 0 + −0 + transitions in nuclei. We also give a general method of determining the mass of a particle from the energy of its decay products alone, which does not seem to be well known.
61 citations
TL;DR: Results suggest that a considerable proportion of the enzyme is associated with the plastid fraction of the cell, and the source of ATP and information on the metabolic role, for glutamine synthetase may be suggested.
Abstract: Glutamine is of considerable importance in plants, as a readily metabolised and translocated intermediate and as a product of ammonia detoxification. Glutamine synthetase carries out the ATP-driven addition of ammonia to glutamate to produce the amide. The source of ATP and information on the metabolic role, for glutamine synthetase may be suggested by determining the location of this enzyme within the cell. Earlier work1 suggested that glutamine synthetase was located in mitochondria, although later investigation2 did not confirm this. We have found considerable amounts of glutamine synthetase in leaf tissues3 and recent results now suggest that a considerable proportion of the enzyme is associated with the plastid fraction of the cell.
61 citations
TL;DR: From rotating copper disk electrochemistry and analysis of potentiostatic transients, it was demonstrated that copper dissolves reversibly as Cu(OH) 4 −2, and that passivation of the electrode surface occurred by a nucleation and growth mechanism similar in principle to that proposed by Armstrong et al. as mentioned in this paper.
51 citations
TL;DR: In this article, conditions under which methods of direct neurological manipulation may be of utility in the study of brain-behavior relations and cerebral localization of function are discussed, with attention being directed in particular to the conflict of positions represented by R. Gregory and L. Weiskrantz.
Abstract: The conditions under which methods of direct neurological manipulation may be of utility in the study of brain-behavior relations and of cerebral localization of function are discussed, with attention being directed in particular to the conflict of positions represented by R. L. Gregory and L. Weiskrantz. The argument is made that such methods are potentially useful only if the nervous system or particular portions of the nervous system can be conceptualized in terms of being a parallel, rather than a serial information processing system. It is further argued that inferences made on the basis of results generated with such methods (and indeed any method) are dependent upon the assumptions and conceptualizations concerning brain function held by the E.
50 citations
TL;DR: Research discussed includes the topics of anatomical locus of septal damage, species and strain investigated, pre- and post-operative handling, neurochemical factors, and the relationship of hyper-reactivity to other sePTal dysfunctions and other anatomical structures.
Abstract: The literature related to one form of septal dysfunction - hyper-reactivity - is reviewed. The increase in reactivity following septal damage is considered in terms of its reliability and the many factors which influence its attenuation and release. Research discussed includes the topics of anatomical locus of septal damage, species and strain investigated, pre- and post-operative handling, neurochemical factors, and the relationship of hyper-reactivity to other septal dysfunctions and other anatomical structures.
48 citations
TL;DR: One hundred and twenty-seven oriented samples of the Dubawnt Group were collected from 32 sites (10 sites in igneous rocks and 22 in sedimentary rocks) along the shores of Baker Lake, Northwest Territories (mean location of sampling sites 64.1° N., 094.7° W.). The age of the rocks is in the range 1,720 to 1,735 m.y as mentioned in this paper.
Abstract: One hundred and twenty-seven oriented samples of the Dubawnt Group were collected from 32 sites (10 sites in igneous rocks and 22 in sedimentary rocks) along the shores of Baker Lake, Northwest Territories (mean location of sampling sites 64.1° N., 094.7° W.). The age of the rocks is in the range 1,720 to 1,735 m.y. Demagnetization studies, the observed consistency between igneous and sedimentary rocks, the presence of reversals, and the evidence from baked contacts indicate that the magnetization was acquired at or very soon after formation. The mean direction of magnetization, irrespective of sign, is 347°, −50° (α 95 = 7°), and the corresponding pole is 07° N., 083° W. (α 95 = 8°). This result, together with others recently obtained, suggests that relative to North America the pole followed a westerly track in the eastern Pacific Ocean during the middle Proterozoic. These rocks are not very different in age from the Sudbury Irruptive, and the results therefore allow a tentative reconstruction of the original attitude of the northern limb of the irruptive.
TL;DR: In this paper, the crystal field splittings of europium gallium garnet and terbium aluminum garnet were derived from light scattering, fluorescence, and absorption spectra.
Abstract: The crystal-field splittings of the $^{7}F$ multiplet of ${\mathrm{Eu}}^{3+}$ and ${\mathrm{Tb}}^{3+}$ have been determined in europium gallium garnet (EuGaG) and terbium aluminum garnet (TbAlG) from light scattering, fluorescence, and absorption spectra. The data were used to derive a set of crystal-field parameters for the two garnet systems. In these calculations the Hamiltonian appropriate for the ${D}_{2}$ symmetry of the rare-earth sites and also the mixing of different $J$ states by the crystal field were taken into account. From the eigenfunctions derived in this way the magnetic-susceptibility-versus-temperature curve was calculated for TbAlG.
TL;DR: The effects of large insular-temporal lesions are more severe for pure tone pattern discriminations than for FM patterns, and both FM and pure tone patterns were easily relearned and no differences were seen for the two types of pattern discrimination.
TL;DR: Sensitivity (of NADH-GDH) to glutamate was lost on purification, but was restored when the enzyme was immobilized by binding to an insoluble support (AE cellulose).
TL;DR: In this paper, the relationship of gains to the integration process is examined and the salience of the former is obscured by complex models in which the saliency of the latter is obscured.
Abstract: Integration theorists are increasingly turning their attention away from an examination of the relationship of gains to the integration process and towards the elaboration of complex models in which the salience of the former is obscured. As this variable appears to influence the durability of integrative systems among third-world countries and, by entering into actor calculations of alternatives, effects changes within the integrative system, an analysis is warranted which places the relationship of gains to the integration process in bolder relief.
TL;DR: The anti-convulsant properties of δ 9-trans-tetrahydrocannabinol (δ9-THC) were examined in rats subjected to daily convulsions induced by direct electrical stimulation of either the anterior limbic cortex or the amygdala and, initially, the drug had a very pronounced effect on the sub-cortical seizures and a slightly lesser effect onthe cortical seizures.
Abstract: The anti-convulsant properties of δ9-trans-tetrahydrocannabinol (δ9-THC) were examined in rats subjected to daily convulsions induced by direct electrical stimulation of either the anterior limbic cortex or the amygdala. During the development of the convulsions (kindling) and during the repeated daily injections of δ9-THC, electroencephalographic records were taken. THC was administered daily until the animals were behaviorally tolerant. The drug had, initially, a very pronounced effect on the sub-cortical seizures and a slightly lesser effect on the cortical seizures—either stopping them entirely or reducing their duration. However, as the animals became tolerant to THC (defined behaviorally and electrically), the anti-convulsant properties of the drug diminished.
TL;DR: Innate capacity for increase of the Mediterranean Hour moth, Anagasta kuehniella (Zeller), was higher at constant than at alternating temperatures because of shorter developmental times, earlier attainment of maximum fecundity, and greater survival of immature stages at constant temperatures.
Abstract: Innate capacity for increase (rm) of the Mediterranean Hour moth, Anagasta kuehniella (Zeller), was higher at constant than at alternating temperatures because of shorter developmental times, earlier attainment of maximum fecundity, and greater survival of immature stages at constant temperatures.
Increased amplitude of alternating temperatures decreased survival of immature stages, rates of development, and fecundity, and thus reduced rate of population growth.
Preliminary mathematical models relating innate capacity for increase to temperature are developed. These are:
rm=0.1583—0.00128 [33.33 e0.003048 (35.5-t°C)2]
for constant temperatures and
rm=0.1583—0.00128 [36.76 e0.003002 (34.6-t°C)2]
for alternating temperatures. The average deviation of empirical from computed values is 3%. The efficacy of these models is restricted to temperatures favorable for reproduction.
TL;DR: Using a theorem of Jacques Lewin, the zero divisor question for group rings of supersolvable groups was solved in this paper, where the authors showed that it is solvable.
Abstract: Using a theorem of Jacques Lewin, the zero divisor question is solved for group rings of supersolvable groups.
TL;DR: In this article, the authors found that β-glucosidase is involved in the development of the lateral root rather than its penetration through the cortex of the young primordium.
Abstract: With 6-bromo-2-naphthyl-β-D-glucoside as substrate, β-glucosidase activity has been histochemically localized in the lateral root meristems ofZea mays. Enzyme activity is highest in the epidermis and root cap of the young primordium. In contrast, enzyme activity is low in the parent root cortex, including the damaged areas around the lateral root. The results indicate that β-glucosidase is involved in the development of the lateral root rather than its penetration through the cortex.
TL;DR: The primary purpose of this experiment was to test compound and coordinate bilinguals, using the release from proactive interference technique, the release being associated with a change in the language of presentation.
Abstract: The primary purpose of this experiment was to test compound and coordinate bilinguals, using the release from proactive interference technique, the release being associated with a change in the language of presentation. It was expected that coordinate bilinguals would show considerable release but that compound bilinguals would not.
TL;DR: It is now appropriate to reexamine the methods used in studies of children with minimal brain dysfunction to develop novel ways of setting up and identifying new Criteria.
Abstract: One way of reviewing advances in a field of scientific study is to examine changes in the selection and use of criteria. The criteria used in neurological and psychological studies have changed from time to time as a function of the sensitivity of the assessment techniques as well as of the investigator’s ability to coordinate and integrate information. For example, in medicine there are rarely more than five to seven criteria for a diagnosis, because of human limitations: when looking at a specific group of symptoms, a doctor will rarely be able to recall more than a few criteria. With the development of computerized data storage and retrieval systems, however, this limitation can be eliminated. Studies of children with minimal brain dysfunction (MBD) have used a wide variety of criteria to determine their unique characteristics. For example, they have been classified on such variables as medical history, physical findings, neurological signs, biochemical data, EEG patterns, behavior ratings by parents and teachers, and scores on a large number of psychological tests. Great effort has been required in order to provide any new information in studies of this nature. In an attempt to develop novel ways of setting up and identifying new Criteria, it is now appropriate to reexamine the methods used in studies of such children.
TL;DR: The effects of several DDT and methoxychlor analogs on trout fingerling temperature selection and lethality were investigated in this paper, where the molecular requirements for lethality and alteration of temperature selection were different.
TL;DR: Electroencephalographic data indicated that, 15 min after smoke administration, cortical and hippocampal electrical activity was similar to that seen 25 min after interperitoneal injections of Δ9-tetrahydrocannabinol (THC).
Abstract: A new inhalation apparatus for rats is described for administrating Cannabis smoke in a standardized, controlled fashion. Electroencephalographic data indicated that, 15 min after smoke administration, cortical and hippocampal electrical activity was similar to that seen 25 min after interperitoneal injections of Δ9-tetrahydrocannabinol (THC). A comparison of 30 mg/kg THC given orally, 4 mg/kg THC injected interperitoneally, and an estimated 17.5 mg/kg THC inhaled in Cannabis smoke indicated that all three modes of drug administration resulted in a significant reduction of open-field activity with the injection route being the most effective.
TL;DR: In this paper, the authors discuss the radiochemistry of organometallic compounds and the physical aspects of the nuclear reaction and subsequent atomic processes that occur in times too short to constitute conventional chemistry, and describe studies of historical and practical significance that lead either to the understanding of the phenomena or to important questions.
Abstract: Publisher Summary This chapter discusses the radiochemistry of organometallic compounds. It describes the physical aspects of the nuclear reaction and subsequent atomic processes that occur in times too short to constitute conventional chemistry. Although the experiments are conceptually simple, they are not widely known and deserve clarification. The chapter describes studies of historical and practical significance that lead either to the understanding of the phenomena or to important questions. There are a number of questions of a fundamental nature that preclude much further progress in the field before any additional insight is available. Both alkyl and aryl metals have been studied but not a very wide range of compounds. Several studies of triphenylarsene and triphenylstibine have been done. The only other area to which the hot atom chemistry of organometallic compounds has so far been applied is isotope enrichment.