Showing papers by "Carleton University published in 1988"
TL;DR: In this article, a new chemical index of weathering that can be applied to modern soils and Precambrian paleosis is proposed: CIW = [Al2O3].
1,152 citations
605 citations
539 citations
TL;DR: In this paper, the authors proposed a resampling method based on the balanced repeated replication (BRR) method for stratified multistage multi-stage designs with replacement, in particular for two sampled clusters per stratum.
Abstract: Methods for standard errors and confidence intervals for nonlinear statistics —such as ratios, regression, and correlation coefficients—have been extensively studied for stratified multistage designs in which the clusters are sampled with replacement, in particular, the important special case of two sampled clusters per stratum. These methods include the customary linearization (or Taylor) method and resampling methods based on the jackknife and balanced repeated replication (BRR). Unlike the jackknife or the BRR, the linearization method is applicable to general sampling designs, but it involves a separate variance formula for each nonlinear statistic, thereby requiring additional programming efforts. Both the jackknife and the BRR use a single variance formula for all nonlinear statistics, but they are more computing-intensive. The resampling methods developed here retain these features of the jackknife and the BRR, yet permit extension to more complex designs involving sampling without replace...
445 citations
TL;DR: Responses of neurons in the auditory cortex of the albino rat were examined using microelectrode mapping techniques and suggest the presence of other auditory fields, the detailed characteristics of which have yet to be examined.
Abstract: 1. Responses of neurons in the auditory cortex of the albino rat were examined using microelectrode mapping techniques. Characteristic frequencies were determined for numerous electrode penetrations across the cortical surface in individual animals. A primary auditory area was identified in the posterolateral neocortex that was characterized by short latency responses to tone bursts and tonotopic organization with high frequencies represented rostrally and low frequencies, caudally. Within this area cells with similar characteristic frequencies were aligned in a dorsoventral orientation to form isofrequency contours. 2. Tuning curves obtained from primary auditory cortex were characteristically "V" shaped with Q10's ranging from 0.97 to 28.4. Maximum Q10 values increased monotonically with characteristic frequency (CF). The lowest thresholds at CF closely approximated the behavioral audiogram for the albino rat. Many neurons, however, had CF thresholds well above the behavioral limit. 3. Areas were found dorsal and ventral to the primary auditory cortex in which CF's were clearly discontinuous with the neighboring isofrequency contours. These data suggest the presence of other auditory fields, the detailed characteristics of which have yet to be examined.
310 citations
TL;DR: The results of temporally and spatially distributed wideband (impulse response) propagation experiments in the 900 MHz and 1.7 GHz radio frequency bands in two different buildings on fixed indoor radio links are reported.
Abstract: The results of temporally and spatially distributed wideband (impulse response) propagation experiments in the 900 MHz and 1.7 GHz radio frequency bands in two different buildings on fixed indoor radio links are reported. Results from the temporal experiments show that, for a specific location in either of the two buildings, the dynamics of indoor channels are slightly less random at 910 MHz than at 1.7 GHz. It is believed that this would result in marginally better performance on a given transmit/receive link in the 900 MHz band. The spatially distributed measurements showed that the structures of average impulse-response envelopes differed for channels in the two buildings. In one building, RMS delay spreads were slightly greater in the 1.7 GHz band for over 90% of transmit/receive link configurations. In the other building, RMS delay spreads were marginally greater in the 900 MHz band for 70% of the configurations. >
232 citations
TL;DR: The motor, mental, and language development plus the home environment was examined in 217 twelve-month and 153 twenty-four-month-old children for whom prenatal exposure to marijuana, alcohol and cigarettes was previously ascertained and a transactional interpretation is presented.
213 citations
TL;DR: The authors assesses the state-of-the-art on the subject of international market selection based on a comprehensive review and synthesis of the literature and provides an inventory, taxonomy and brief review of the normative quantitative models that have been proposed in the literature, and compares them to current business practices in selecting foreign markets.
Abstract: This article assesses the state‐of‐the‐art on the subject of international market selection based on a comprehensive review and synthesis of the literature. It provides an inventory, taxonomy and brief review of the normative quantitative models that have been proposed in the literature, and compares them to current business practices in selecting foreign markets. This comparison reveals a theory‐practice gap that is discussed in the context of the methodological and conceptual weaknesses of the models. Suggestions for future research are made.
210 citations
TL;DR: In this paper, the development of coherent soil sheaths on the distal 30-cm of maize roots, and the loss of the sheaths further back, led to the differences in surface structure, anatomy, carbon exudation and microflora of sheathed and bare zones.
Abstract: Recent work in our laboratory provides evidence for a revised view of the functioning of roots of maize, and probably of all the grasses. The development of coherent soil sheaths on the distal 30-cm of these roots, and the loss of the sheaths further back, led us to investigate the differences in surface structure, anatomy, carbon exudation and microflora of the sheathed and bare zones. The significant differences are summarized. But the fact which underlies all these differences is the maturation of the late metaxylem (LMX). In the sheathed zones the LMX elements are still alive and non-conducting; only the early metaxylem (EMX) and protoxylem are open. In the bare zones they are open vessels. This leads directly to the dryness of bare zones and the wetness of sheathed zones, and indirectly to the other differences noted. Branch root junctions are shown to be structures of great significance. Besides connecting the branches to the axile systems, they serve also to connect the EMX and LMX vessels, and contain a tracheid barrier which prevents air embolisms entering the main vessels. These discoveries force us to revise the traditional view of water uptake by the root hair zone, and to suggest that much water must also enter bare roots, possibly via the laterals. There is some published evidence for this. The living LMX elements of the sheathed zone accumulate large concentrations of potassium which must join the transpiration water at the transition to the bare zone. Calculations suggest that this may be only a tenth of the requirement of a mature plant, and that the balance may enter the bare zones with the transpiration water.
147 citations
TL;DR: This study investigated age-related differences in working memory using a modified version of the Daneman and Carpenter (1980) working memory task, which required subjects to verify a series of sentences, and then at the end of each series recall the final word of each sentence.
Abstract: This study investigated age-related differences in working memory using a modified version of the Daneman and Carpenter (1980) working memory task. The subjects were required to verify a series of sentences, and then at the end of each series recall the final word of each sentence. Each series varied in length from one to five sentences. Performance on this task was compared with performance in a word-alone condition, in which the subject had to remember an equivalent list of single words but without sentence verification. When sentences of positive grammatical form were used in the sentence-span condition, age differences were no greater than in the word alone condition; however, the age decrement increased when sentences of negative grammatical form were used. There were no interactions between age and pacing or between age and the number of sentences in each set. These results are discussed in relation to theories of age differences in working memory.
146 citations
TL;DR: In this article, a detailed field mapping of the crustal sequence in several areas of the Sumail Ophiolite Nappe, mainly in the Fizh, the Salahi and the Haylayn blocks, and comparisons with other well-studied areas, have shown that the crust was constructed by two distinct, although nearly contemporaneous, magmatic series: the first, a gabbroic series, was emplaced during the accretion stage at an oceanic spreading centre which formed the layered gabbra unit, the high-level isotropic g
TL;DR: A computer algorithm originally developed for predicting the hardenability of low alloy steels has been adapted to forecast the microstructural development in weld heat-affected zones (HAZ) as mentioned in this paper.
TL;DR: Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation, and a survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3- fold increase in blood glycerol in response to freezing.
Abstract: Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. Turtles survived frequent exposures to temperatures as low as -6 degrees C to -8 degrees C in their shallow terrestrial nests over the 1987-1988 winter. Hatchlings collected in April 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees C and survived 24 hr of freezing at -4 degrees C with 53.4% +/- 1.98% of total body water as ice. Recovery appeared complete after 20 hr of thawing at 3 degrees C. However, freezing at -10.9 degrees C, resulting in 67% ice, was lethal. A survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3-fold increase in blood glycerol in response to freezing. Although quantitatively low, these responses by spring turtles strongly indicate that these may be the winter-active cryoprotectants. The total amino acid pool of blood also increased 2.25-fold in freezing-exposed turtles, and taurine accounted for 52% of the increase. Most organs accumulated high concentrations of lactate during freezing, a response to the ischemic state imposed by extracellular freezing. Changes in glycogen phosphorylase activity and levels of glucose 6-phosphate and fructose 2,6-bisphosphate were also consistent with a dependence on anaerobic glycolysis during freezing. Studies of the molecular mechanisms of natural freeze tolerance in these turtles may identify protective strategies that can be used in mammalian organ cryopreservation technology.
TL;DR: Behavioral changes induced by inescapable shock were examined in six strains of mice and Y-maze spontaneous alteration performance was not affected by the shock treatment, although a strain-dependent increase of perseverative responses was evident.
Abstract: Behavioral changes induced by inescapable shock were examined in six strains of mice. Exposure to shock provoked time-dependent disturbances of shuttle escape performance. In some strains the shock treatment did not affect escape performance, whereas in others profound performance deficits were evident. The inescapable shock treatment likewise induced strain-dependent alterations of performance in a forced-swim task. In most instances the shock treatment initially provoked invigorated responding, but in other strains the shock had no effect or depressed active responding. Finally, Y-maze spontaneous alteration performance was not affected by the shock treatment, although a strain-dependent increase of perseverative responses was evident. The occurrence of a stressor-induced deficit in one task in a particular strain of mouse was not predictive of behavioral alterations in a second task. These data are discussed with respect to animal models of depression and genetic differences associated with the response to stressors.
TL;DR: Three deterministic learning automata solutions to the problem of equipartitioning are presented, although the first two are epsilon -optimal, they seem to be practically feasible only when a set of W objects is small.
Abstract: Three deterministic learning automata solutions to the problem of equipartitioning are presented. Although the first two are epsilon -optimal, they seem to be practically feasible only when a set of W objects is small. The last solution, which uses a novel learning automaton, demonstrates an excellent partitioning capability. Experimentally, this solution converges an order of magnitude faster than the best known algorithm in the literature. >
TL;DR: In this paper, the authors estimate that the Archean oceanic lithosphere had a "sandwich" rheology, with the lower crust behaving as a soft, ductile layer.
Abstract: Assuming that the Archean mantle was hotter and the oceanic crust thicker than at present, we estimate that the Archean oceanic lithosphere had a "sandwich" rheology, with the lower crust behaving as a soft, ductile layer Accordingly, the Archean oceanic lithosphere had a rheological structure similar to present-day continental lithosphere but unlike present-day oceanic lithosphere The thickness of the ductile layer is a decreasing function of age, while its strength is an increasing function of age The buoyancy problem in Archean subduction could be overcome by delamination of oceanic upper crust, but mass balance calculation indicates that most Archean oceanic crust must have been recycled Where the right dynamic conditions existed for delamination, oceanic flake tectonics may have been an important process leading to the preservation of oceanic upper crust in "greenstone belts" that are characteristic of Archean terrains
TL;DR: In this article, the authors define the category of all right (resp. left) A-modules for an artin algebra A and the ordinary duality functor is denoted by D: mod-A 2 A-mod, i.e., D = Hom,(?, f) with the minimal injective cogenerator I over k.
TL;DR: In this article, a review of variance estimation techniques for nonlinear statistics, such as ratios and regression coefficients, and functionals such as quantiles, are reviewed in the context of sampling from stratified populations.
Abstract: Variance estimation techniques for nonlinear statistics, such as ratios and regression and correlation coefficients, and functionals, such as quantiles, are reviewed in the context of sampling from stratified populations. In particular, resampling methods such as the bootstrap, the jackknife, and balanced repeated replication are compared with the traditional linearization method for nonlinear statistics and a method based on Woodruff's confidence intervals for the quantiles. Results of empirical studies are presented on the bias and stability of these variance estimators and on confidence‐interval coverage probabilities and lengths. Copyright
TL;DR: Generally, responses from each of the three binaural classes were well represented over the rat's hearing range and there was some tendency for summation responses to prevail at lower frequencies and suppression responses to prevailed at higher frequencies but the differences were not large.
Abstract: 1. The binaural response properties of neurons in the auditory cortex of the albino rat were examined using microelectrode mapping techniques. Characteristic frequencies, binaural response classes,...
TL;DR: In this article, the asymptotic behavior of U-statistics type processes which can be used for detecting a changepoint of a random sequence is studied and invariance principles for these processes are proved.
TL;DR: Agrobacterium-mediated transformation of thin cell layer explants yielded large numbers of transgenic plants of a major Canadian rapeseed cultivar Brassica napus ssp.
Abstract: Agrobacterium-mediated transformation of thin cell layer explants (Klimaszewska and Keller 1985) yielded large numbers of transgenic plants of a major Canadian rapeseed cultivar Brassica napus ssp. oleifera cv Westar. The morphology and fertility of these plants were indistinguishable from controls. The Ti plasmid vector, pGV3850 (Zambryski et al. 1983) was used as a cis vector and as a helper plasmid for the binary vector pBin19 (Bevan 1984). Selectable marker genes that conferred resistance to high levels of kanamycin (Km) on Nicotiana tabacum were less efficient in the selection of transgenic B. napus. At low levels of Km (15 μg/ml) large numbers of transgenic plants (50%) were identified among the regenerants by nopaline synthase activity and several of these were confirmed by Southern blot analyses. Only a small number were resistant to higher levels of Km (80 μg/ml). Preliminary analyses indicated that resistance to Km was transmitted to the selfed progeny. Chimeric chloramphenicol acetyl transferase genes were ineffective biochemical markers in transgenic B. napus.
TL;DR: Signed-digital number representation systems have been defined for any radix r>or=3 with digit values ranging over the set (- alpha,...,1,0,1,..., alpha ), where alpha is an arbitrary integer in the range r/2.
Abstract: Signed-digital number representation systems have been defined for any radix r>or=3 with digit values ranging over the set (- alpha ,...,-1,0,1,..., alpha ), where alpha is an arbitrary integer in the range r/2 >
TL;DR: The dynamic nature of the farm landscape is introduced through examples of small mammal populations, distribution and abundance of birds, ecological effects of matter moving to and from organisms and the forces of human intellectual activities such as politics and economics.
Abstract: Farm landscapes are a product and a part of human culture. They also are functioning ecological systems. Landscape ecologists are interested in synthesizing a holistic view of this common environment. In this review the dynamic nature of the farm landscape is introduced through examples of small mammal populations, distribution and abundance of birds, ecological effects of matter moving to and from organisms and the forces of human intellectual activities such as politics and economics. This wide range of topics over which landscape ecology attempts its synthesis produces some conceptual and technical problems which are characteristic of this new field. Prominent among them are questions of heterogeneity and scale in both space and time.
TL;DR: Determination of HCPs offers promise as a specific and sensitive biological marker of PHAH-induced toxicity and as a measure of the toxicological significance of the chemical burden in gulls, terminal members of Great Lakes food chains.
Abstract: Concentrations of highly carboxylated porphyrins (HCPs) in the livers of adult herring gulls (Larus argentatus) from colonies throughout the Great Lakes were found to be markedly elevated in comparison with those in gulls from coastal areas and in seven other species of birds consuming diets uncontaminated with polyhalogenated aromatic hydrocarbons (PHAHs). The highes levels were found in gulls from lower Green Bay (Lake Michigan), Saginaw Bay (Lake Huron) ant Lake Ontario. We suggest that the high levels of HCPs reflect PHAH-induced derangement of heme biosynthesis. Determination of HCPs offers promise as a specific and sensitive biological marker of PHAH-induced toxicity and as a measure of the toxicological significance of the chemical burden in gulls, terminal members of Great Lakes food chains.
TL;DR: HARP's architecture-and the concomitant ready extensibility of its control structure by declarative heuristic rules-renders it easy to let extralogical information, e.g. semantic and world knowledge, guide the search for proofs and help eliminate irrelevant premisses.
Abstract: This paper presents HARP, a complete, tableau-based theorem prover for first order logic, which is intended to be used both interactively and as an inference engine for Artificial Intelligence applications. Accordingly, HARP's construction is influenced by the design goals of ‘naturalness’, efficiency, usefulness in an Artificial Intelligence environment, and modifiability of the control structure by heuristics. To achieve these goals, HARP accepts the entire language of first order logic, i.e. avoids conversion to any kind of normal form, and combines a proof condensation procedure with explicitly represented, declaratively formulated heuristics to construct and communicate its proofs in a format congenial to people. The proof condensation procedure makes proof shorter and more readable by excising redundancies from proof trees. Domain-independent heuristics are formulated to capture efficient and human-like deduction strategies and to rapidly detect certain types of nontheorems. Domain-dependent heuristics can be used to implement specific control regimes, e.g. to efficiently support inheritance. HARP's architecture-and the concomitant ready extensibility of its control structure by declarative heuristic rules-renders it easy to let extralogical information, e.g. semantic and world knowledge, guide the search for proofs and help eliminate irrelevant premisses.
TL;DR: The data on the binaural properties of cells in the crown of the ectosylvian auditory cortex of barbiturate-anesthetized ferrets, and the spatial distribution of those cells, provide the first evidence in a species other than the cat for segregated bINAural representation in the auditory cortex.
TL;DR: Three distinct types of decision-making processes are found, termed sporadic, fluid and constricted processes, which, given the variety of the 30 organizations from which the cases are drawn, should be generalizable to a wide range of contexts.
Abstract: Using 136 cases of strategic decision-making described by a number of variables drawn from the literature, three distinct types of decision-making processes are found. These are termed sporadic, fluid and constricted processes. They are parsimonious characterizations of decision-making processes which, given the variety of the 30 organizations from which the cases are drawn, should be generalizable to a wide range of contexts.
TL;DR: Control of glycolysis during anoxia was investigated in five organs of the freshwater turtle, Pseudemys scripta, after 1 or 5 h of submergence in N2-bubbled water, and changes in the levels of hexose and triose phosphate intermediates of glyCOlysis indicated an activation and inhibition in brain, heart, and skeletal muscles.
Abstract: Control of glycolysis during anoxia was investigated in five organs (heart, brain, liver, and red and white skeletal muscles) of the freshwater turtle, Pseudemys scripta, after 1 or 5 h of submergence in N2-bubbled water. Lactate was produced as the metabolic end product, with distinct organ differences in the amount (net lactate accumulation was 2.4-fold higher in brain than white muscle) and rate (lactate production in liver dropped 16-fold after the 1st h) of lactate accumulation. ATP and total adenylate contents of all organs were reduced (by 15-32%) after 1 h of submergence, but energy charge was maintained; after 5 h, adenylate contents had fully recovered. Changes in the levels of hexose and triose phosphate intermediates of glycolysis indicated an activation of glycolysis within the 1st h of anoxia exposure in brain, heart, and skeletal muscles. By 5 h, however, these were reversed, and a glycolytic rate depression was indicated, consistent with the overall metabolic rate depression accompanying long-term anaerobiosis in the turtle. Crossover analysis indicated glycolytic control at the pyruvate kinase reaction in all organs during both glycolytic activation and metabolic depression; regulatory control at the phosphofructokinase locus was primarily important only during glycolytic activation in heart and red muscle. The same analysis indicated a very rapid glycolytic inhibition in liver occurring within the 1st h of anoxia exposure; this allows glycogenolysis to be directed toward glucose export yielding the fermentative fuel used by other organs during anoxia.
TL;DR: The results indicate that the evolutionarily conserved Mr 68000 glycoprotein is involved in transport processes of karyophilic proteins from the cytoplasm into the nucleus.
Abstract: Using a monoclonal antibody (PI1) raised against mouse lymphocyte nuclear matrix fractions we have identified a N-acetylglucosamine (G1cNAc)-containing glycoprotein of Mr 68000 as a component of the nuclear pore complexes of Xenopus laevis oocytes. The antigenic determinant recognized by antibody PI1 comprises both the sugar moiety and protein sequences since, on the one hand, added G1cNAc competed effectively for antibody binding and, on the other hand, the antibody reacted in immunoblots with only one member of the G1cNAc-containing pore complex glycoprotein family. By using immunogold-electron microscopy we could demonstrate that the Mr 68000 glycoprotein was located preferentially to the cytoplasmic side of the pore complex channel. When radiolabeled soluble nuclear proteins were injected into the cytoplasm of Xenopus oocytes, their reentry into the nucleus was almost completely inhibited in the presence of antibody PI1 as shown by two-dimensional gel electrophoresis. The results indicate that the evolutionarily conserved Mr 68000 glycoprotein is involved in transport processes of karyophilic proteins from the cytoplasm into the nucleus.