Showing papers by "North Carolina State University published in 1979"
TL;DR: In this article, the limit distributions of the estimator of p and of the regression t test are derived under the assumption that p = ± 1, where p is a fixed constant and t is a sequence of independent normal random variables.
Abstract: Let n observations Y 1, Y 2, ···, Y n be generated by the model Y t = pY t−1 + e t , where Y 0 is a fixed constant and {e t } t-1 n is a sequence of independent normal random variables with mean 0 and variance σ2. Properties of the regression estimator of p are obtained under the assumption that p = ±1. Representations for the limit distributions of the estimator of p and of the regression t test are derived. The estimator of p and the regression t test furnish methods of testing the hypothesis that p = 1.
23,509 citations
TL;DR: An algorithm is presented which solves the problem of determining the distance from T to T' as measured by the mlmmum cost sequence of edit operaUons needed to transform T into T'.
Abstract: The tree-to-tree correctmn problem Is to determine, for two labeled ordered trees T and T', the distance from T to T' as measured by the mlmmum cost sequence of edit operaUons needed to transform T into T' The edit operations investigated allow changing one node of a tree into another node, deleting one node from a tree, or inserting a node into a tree An algorithm Is presented which solves this problem m time O(V* V'*LZ* L'2), where V and V' are the numbers of nodes respectively of T and T', and L and L' are the maximum depths respectively of T and T' Possible apphcatmns are to the problems of measuring the similarity between trees, automatic error recovery and correction for programming languages, and determining the largest common substructure of two trees
938 citations
TL;DR: General use of Burrows' composite measure of linkage disequilibrium, whether or not random union of gametes is an appropriate assumption, is recommended and attention is given to small samples, where the non-normality of gene frequencies will have greatest effect on methods of inference based on normal theory.
Abstract: Existing theory for inferences about linkage disequilibrium is restricted to a measure defined on gametic frequencies. Unless gametic frequencies are directly observable, they are inferred from genotypic frequencies under the assumption of random union of gametes. Primary emphasis in this paper is given to genotypic data, and disequilibrium coefficients are defined for all subsets of two or more of the four genes, two at each of two loci, carried by an individual. Linkage disequilibrium coefficients are defined for genes within and between gametes, and methods of estimating and testing these coefficients are given for gametic data. For genotypic data, when coupling and repulsion double heterozygotes cannot be distinguished. Burrows' composite measure of linkage disequilibrium is discussed. In particular, the estimate for this measure and hypothesis tests based on it are compared to the usual maximum likelihood estimate of gametic linkage disequilibrium, and corresponding likelihood ratio or contingency chi-square tests. General use of the composite measure, whether or not random union of gametes is an appropriate assumption, is recommended. Attention is given to small samples, where the non-normality of gene frequencies will have greatest effect on methods of inference based on normal theory. Even tools such as Fisher's z-transformation for the correlation of gene frequencies are found to perform quite satisfactorily.
487 citations
TL;DR: In this paper, statistical inference for a system of simultaneous, non-linear, implicit equations is discussed and the authors consider inference as an adjunct to two-and three-stage least squares estimation rather than in a general setting.
353 citations
TL;DR: Evidence is presented that effective mutualism occurs between two species which also compete for pollination and which act as mutualistic partners at the same time that their sequential flowering is maintained by competition.
Abstract: Since the theoretical paper of Levin and Anderson1, it has been widely recognised that animal pollinators represent resources for which plants can compete Competition for pollination might take several forms and act as a powerful selective force in establishing or maintaining sequential flowering among sympatric species2 Sequential flowering in Arctic3, temperate4–9 and neotropical10–13 plant assemblages has been interpreted as an evolutionary result of competition for pollination This interpretation may prove correct in many cases, although strong evidence for competition is available for few systems9,14 Heinrich and Raven15 (see also Baker16 and Baker et al17) pointed out that sympatric plant species may act as mutualistic partners at the same time that their sequential flowering is maintained by competition We develop this hypothesis here explicitly and present evidence that effective mutualism occurs between two species which also compete for pollination
254 citations
TL;DR: Estimated ingestion rates of total dry material by benthic invertebrate deposit feeders and detritivores feeding at 15°C could be explained almost entirely by organic content of the ingested material and body size, and the relation was consistent for 19 species from 3 phyla.
Abstract: Published ingestion rates of total dry material (inorganic and organic) by benthic invertebrate deposit feeders and detritivores feeding at 15°C could be explained almost entirely by organic content of the ingested material and body size; the relation was consistent for 19 species from 3 phyla. Since ingestion rate of total dry material varied inversely with the organic content of the food, organic matter ingestion (C) was essentially a function of body size (W): [Formula: see text] where C is mg day-1 and W is mg dry weight. These animals may maintain a rate of intake of organic matter which is independent of the organic content of the food source by: (1) Actively adjusting their feeding rates according to some perception of food "quality", and/or (2) Adapting their feeding rates to different environments on an evolutionary time scale.
233 citations
TL;DR: The liquid-repair method is effective for enumeration by the MPN technique and isolation of pathogenic and indicator bacteria from different types of semipreserved foods and the solid- repair method in principle can be used for direct enumeration of any organism which is usually enumerated by the selective plating procedure.
188 citations
TL;DR: In this paper, a control structure for a divisionalized firm is defined to be a set of rules for evaluating division managers and a decision-rule for central coordinating decisions, where each division manager is evaluated on the basis of his own realized profits less the reported impact of the change in coordinating decisions resulting from his message on the profits of the other divisions.
Abstract: This paper examines the problems of coordinating and controlling divisions of a large firm. Divisions are typically interdependent and the corporate headquarters plays an important role in coordinating such decisions as pricing, allocation of funds to the divisions, and determining the level of corporate-wide research and development. One important problem is how to provide division managers with incentives both to act in congruence with the goals of the overall firm and to transmit accurate information to the corporate center so that the center's decisions may be enhanced.
The analysis proceeds by assuming that each division manager possess perfect knowledge of his own division's technology and the market conditions it faces. Each division's profits, however, depend upon certain coordinating decisions taken by the center. The center is assumed to be at least partially ignorant about the operations of the divisions and to rely upon information from the divisions in making coordinating decisions.
A control structure for a divisionalized firm is defined to be a set of rules for evaluating division managers and a decision-rule for central coordinating decisions. Division managers are assumed to act to maximize their evaluation measures so that managerial shirking is not considered. In this setting where perfect information is available, problems of risk aversion and risk sharing do not arise, and a minimum test for optimality of a control structure is given. Specifically, when each division manager seeks to maximize his own evaluation measure and when the center uses its decision-rule for coordination, overall firm profits should be maximized.
A control structure is proposed in which the center acts as if it is receiving “truthful” information from the division managers. This naive decision rule is justified by the accompanying evaluation measures that provide division managers with incentives to communicate in an honest manner. With the proposed evaluation measures, each division manager is rewarded on the basis of his division's contribution to overall profits. If the division's message to the center has no impact on the center's coordinating decisions, then the manager is evaluated on the basis of his own division's realized profits. If the division's message changes the coordinating decision, then the manager is evaluated on the basis of his division's realized profits less the reported impact of the change in coordinating decisions resulting from his message on the profits of the other divisions. It is shown that with this evaluation measure, a division manager is best off communicating truthfully, regardless of the messages of all others. The proposed control structure, therefore, provides an alternative to traditional profit-sharing. An application of the control structure to a resource allocation problem is also given.
162 citations
TL;DR: Three experiments were performed to examine the reverberation cue to egocentric auditory distance and to determine the extent to which such a cue could provide ‘absolute’, as contrasted with ‘relative’; information about distance.
Abstract: Three experiments were performed to examine the reverberation cue to egocentric auditory distance and to determine the extent to which such a cue could provide ‘absolute’, as contrasted with ‘relative’, information about distance. In experiment 1 independent groups of blindfolded observers (200 altogether) were presented with broadband noise from a speaker at one of five different distances (0·55 to 8 m) in a normal hard-walled room. Half of each group of observers were presented with the sound at 0 deg azimuth, followed (after a delay) by the identical sound at 90 deg azimuth. The order of presentation was reversed for the remaining observers. Perceived distance varied significantly as a function of the physical distance to the speaker, even for the first presentations. The change in the binaural information between the 0 deg and 90 deg presentations did not significantly modify the results. For both orientations, near distances were overestimated and far distances were underestimated. Experiments 2 and ...
159 citations
TL;DR: White Leghorn hens which were reared and maintained under commercial conditions were force molted by reducing daylength as well as by withdrawing feed and water to induce a pause in egg production.
153 citations
TL;DR: In this paper, the self-diffusion coefficients for lattice and grain boundary transport in high purity CVDβ-SiC are reported for the range 2128 to 2374 K.
Abstract: The14C self-diffusion coefficients for both lattice (D
lc
*
) and grain boundary (D
bc
*
) transport in high purity CVDβ-SiC are reported for the range 2128 to 2374 K. The Suzuoka analysis technique revealed thatD
bc
*
is 105 to 106 faster thanD
bc
*
; the respective equations are given by
$$\begin{gathered} D_{I c}^* = (2.62 \pm 1.83) \times 10^8 exp\left\{ { - \frac{{(8.72 \pm 0.14)eV/atom}}{{kT}}} \right\}cm^2 sec^{ - 1} \hfill \\ D_{b c}^* = (4.44 \pm 2.03) \times 10^7 exp\left\{ { - \frac{{(5.84 \pm 0.09)eV/atom}}{{kT}}} \right\}cm^2 sec^{ - 1} \hfill \\ \end{gathered} $$
A vacancy mechanism is assumed to be operative for lattice transport. From the standpoint of crystallography and energetics, reasons are given in support of a path of transport which involves an initial jump to a vacant tetrahedral site succeeded by a jump to a normally occupied C vacancy.
TL;DR: In this article, the influence of nitrogen level, form, and application method on the growth response of short and tall Spartanina alterniflora was determined in a North Carolina salt marsh.
Abstract: The influence of nitrogen level, form, and application method on the growth response of short and tallSpartina alterniflora was determined in a North Carolina salt marsh. The application of various nitrogen levels increased the aerial standing crop of shortSpartina as much as 172%, but had no significant effect on that of the tall form. Band application produced a significantly greater yield response than broadcast application in both height forms. The yield of shortSpartina increased significantly more from ammonium fertilization than from nitrate, while there was no significant effect of nitrogen form on tallSpartina. Band application of ammonium-nitrogen fertilizer significantly increased the yield of shortSpartina more than band application of nitrate-nitrogen and broadcast application of either nitrogen form.
TL;DR: Tobacco leaves exposed to (14)C-labeled ethylene was shown to be stable to freezing and thawing; and the pi-acceptors, carbon monoxide, cyanide, n-butyl isocyanide, phosphorous trifluoride, and tetrafluoroethylene, were shown to compete with ethylene for binding.
Abstract: Tobacco leaves were exposed to 14C-labeled ethylene (3.7 × 10−2 microliters per liter) in the presence and absence of unlabeled ethylene and other compounds. Most of the [14C]ethylene appears to be bound to displaceable sites. Lineweaver-Burk plots for a one-half maximum response in a tobacco leaf respiration test gave a value of 0.3 microliter per liter for ethylene, 50 microliters per liter for propylene, and 266 microliters per liter for carbon monoxide. Scatchard plots for displacement of [14C]ethylene from the site gave 0.27 microliters per liter for ethylene, 42 microliters per liter for propylene, and 746 microliters per liter for carbon monoxide. At 2%, CO2 displaces about 35% of the bound ethylene, but increasing the concentration to 10% does not displace the remaining [14C]ethylene. A value of 3.5 nanomolar was calculated for the concentration of ethylene-binding sites available to exogenous ethylene. This does not account for the sites occupied by endogenous ethylene, and the total number of binding sites is probably somewhat higher. Using tissue culture material, the system was shown to be stable to freezing and thawing; and the π-acceptors, carbon monoxide, cyanide, n-butyl isocyanide, phosphorous trifluoride, and tetrafluoroethylene, were shown to compete with ethylene for binding.
TL;DR: It was suggested that the evolutions of the chloroplast and mitochondrial DNAs may be independent of each other, that variation of organelle DNA within a species complex of an organism may be the common condition, and that the DNAs of the organelle and nuclear systems evolve in reasonable harmony.
Abstract: Chloroplast and mitochondrial DNAs from six races of annual teosinte (Guatemala, Huehuetenango, Balsas, Central Plateau, Chalco, and Nobogame), perennial teosinte, and maize were compared and grouped by restriction endonuclease fragment analyses. Three groups of chloroplast DNAs were detected: (i) perennial teosinte and Guatemala; (ii) Balsas and Huehuetenango; and (iii) all other teosintes. Four groups of mitochondrial DNAs were separated: (i) perennial teosinte; (ii) Guatemala; (iii) Nobogame; and (iv) all other teosintes. Separation of the teosinte and maize organelle DNAs into five groups (Guatemala; perennial teosinte; Balsas and Huehuetenango; Central Plateau and Chalco; Nobogame and maize) approximated the biosystematic relationships of the taxa. It was suggested that the evolutions of the chloroplast and mitochondrial DNAs may be independent of each other, that variation of organelle DNA within a species complex of an organism may be the common condition, and that the DNAs of the organelle and nuclear systems evolve in reasonable harmony.
TL;DR: A review dealing with recent advances in membrane science can be found in this paper, where the important topics of controlled release of chemicals from polymeric devices and removal of volatile monomers from addition polymers such as poly(vinyl chloride) and poly(acrylonitrile) are also treated.
Abstract: In this review dealing with recent advances in membrane science, the term “membrane” will be used to indicate any medium which acts as a barrier to transport into or out of a region, provides selective transfer of one species over another or regulates the transport of a material to its environment at a controlled rate. In addition to the common usage of the word “membrane” to indicate a dense polymer film, the above definition includes a variety of interesting cases such as highly porous ultrafiltration membranes and hydrophobic liquid membranes with selectivity properties which can be tailored by incorporation of materials which selectively complex with one of the species to be processed. The important topics of controlled release of chemicals from polymeric devices and removal of volatile monomers from addition polymers such as poly(vinyl chloride) and poly(acrylonitrile) are also treated here.
TL;DR: Investigated personality traits that are characteristic of individuals who abuse and neglect children and found rigidity and problems dimensions were the best predictors of abuse.
Abstract: Conducted a literature review to identify personality traits that are characteristic of individuals who abuse and neglect children. On the basis of reported traits, a Child Abuse Potential Inventory that consisted of 334 items was constructed. The Inventory was administered to 19 abusing and 19 matched nonabusing parents. An item analysis was conducted to identify those items that discriminated between abusers and nonabusers. While the best 7 items accounted for slightly over 90% of the variance, the top 25 discriminators accounted for 99% of the variance. A principal axis factoring with oblique promax rotations was performed. Four factors, or dimensions, were identified. They were: loneliness, rigidity, problems and control. Additional analysis indicated that rigidity and problems dimensions were the best predictors of abuse.
TL;DR: The quantity of non-settleable solids was shown to be related to the quantity of extracellular biopolymers excreted by the microorganisms, which contributes to low clarification efficiencies of the activated sludge process.
TL;DR: Maize superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1; abbreviated as SOD) has been resolved into five major electrophoretic forms by starch gel electrophoresis and all five isozymes are present in the tissues examined.
TL;DR: Correlations of elemental concentrations of the plants with redox potentials and/or pH suggest that these two physical variables may be responsible in part for the regulation of S. alterniflora growth in nature by regulating availability of nutritional elements.
Abstract: A greenhouse experiment was designed to investigate the correlations between waterlogging and aeration, and associated changes in pH, redox potentials and sulfide concentrations, on the growth of Spartina alterniflora Loisel. Elemental concentrations of the aerial and root material were determined and used for correlations with growth response. Redox potentials adjusted to pH 7 (Eh 7) ranged from - 184 mv to 5 mv and were highly correlated (r) with aerial and root dry weight biomass (.97 and .97, respectively) and plant height (1.0). The range of soil pH at the conclusion of the study was 6.07 to 6.74 and was negatively correlated with aerial and root dry weight biomass. Sulfide concentrations ranged from 10-2 to 10-7 M and vorrelations with aerial and root dry weights and height were -.85, -.85 and -.87, respectively. High negative correlations were found between sodium and sulfur concentrations and S. alterniflora growth. Positive correlations between potassium, phosphorus, manganese, zinc, copper, iron and growth response were also observed. Correlations of elemental concentrations of the plants with redox potentials and/or pH suggest that these two physical variables may be responsible in part for the regulation of S. alterniflora growth in nature by regulating availability of nutritional elements. SPARTINA ALTERNIFLORA Loisel. is a dominant wetland plant species in East and Gulf Coast salt marshes of the United States. The fact that S. alterniflora survives its rather unique environment of periodic to erratic inundation by salt
TL;DR: The sorption rate and metabolic fate of nitrogen dioxide, a major air pollutant, have been determined for Phaseolus vulgaris by chemiluminescent monitoring and mass spectrometric analysis of nitrogen derived from the plant tissue.
Abstract: The sorption rate and metabolic fate of nitrogen dioxide, a major air pollutant, have been determined for Phaseolus vulgaris (L.). Sorption was determined kinetically by chemiluminescent monitoring of 15 NO 2 removal from the test atmosphere and directly by mass spectrometric analysis of nitrogen derived from the plant tissue. Sorptive processes were first order with respect to 15 NO 2 concentration. Virtually all of the 15 NO 2 taken up was metabolized.
TL;DR: In this article, the molar enthalpy for gas sorption in glassy polymers at a fixed concentration, often called the isosteric enthalpies of sorption, exhibits a clearly discernable minimum when plotted as a function of penetrant concentration.
TL;DR: This simple method of producing Nicotiana tabacum haploids offers an alternative to anther culture.
Abstract: Abundant seeds of high germinability are obtained when Nicotiana tabacum is pollinated by Nicotiana africana. Most of the seedlings die at the cotyledonary stage. The remaining seedlings are viable F 1 hybrids or maternal haploids that can be easily distinguished. This simple method of producing Nicotiana tabacum haploids offers an alternative to anther culture .
TL;DR: The maximum likelihood method for estimating linkage disequilibrium from genotypic data for randomly mating populations is studied and it is recommended that the cubic be solved completely.
Abstract: The maximum likelihood method for estimating linkage disequilibrium from genotypic data for randomly mating populations is studied. Instead of iterative methods for finding a root of the cubic equation for one of the gametic frequencies (Hill, 1974), it is recommended that the cubic be solved completely. For data with some missing genotypic classes, it is further recommended that explicit solutions for the cubic be used.
TL;DR: In this paper, a physical model describing the swelling kinetics of glassy polymers in liquids is presented, using a thermodynamic argument, the stress induced by the penetrant on the glassy matrix is evaluated in terms of the penetration concentration.
TL;DR: It was concluded that the psychological characteristics of noise are at least as important as its physical characteristics in determining level of vigilance performance.
Abstract: 35 subjects, randomly assigned to five groups in a 2 × 2 + 1 between-subjects design, performed a vigilance task under familiar rock, familiar easy-listening, unfamiliar rock, unfamiliar easy-listening, and no music conditions. Familiar music significantly increased heart rate and percent detections and also mitigated the classical vigilance decrement. Type of music had no significant effect. It was concluded that the psychological characteristics of noise are at least as important as its physical characteristics in determining level of vigilance performance.
TL;DR: In this paper, the effects of rate of heating and final internal temperatures on the texture of fish gels were studied using mechanically deboned fish tissues of two species and 2 harvest locations.
Abstract: Effects of rate of heating and final internal temperatures on the texture of fish gels were studied using mechanically deboned fish tissues of 2 species and 2 harvest locations. Generally, rapid heating to 85°C internal temperature (using 100°C steam) produced a firmer, more springy texture in fish gels in comparison with those heated slowly to 70°C internal temperature. However, these thermal effects on gel textures were species and harvest location dependent. Degradations of tropomyosin and myosin observed in cooked fish gels were highly related to gel textural properties. Results further suggested that changes in muscle proteins during heating were caused by proteolytic factor(s) in the sarcoplasmic fraction. The proteolytic crude fraction was isolated and partially characterized. Optimal temperature for proteolytic activity was 60°C; optimal pH was between pH 8.0 and pH 8.5; calcium ion activated the proteolytic activity and the optimal calcium ion concentration for activation was 1 mM; metal chelators, EDTA and EGTA, inhibited the proteolytic activity. A thorough understanding of these proteolytic factors and their subsequent control is important for the utilization of mechanically deboned fish tissues.
TL;DR: The results are consistent with both neutralist, and selectionist hypotheses, but suggest the importance of considering linkage disequilibrium between neutral and selected loci when attempting to explain the dynamics of enzyme polymorphisms.
Abstract: Nine laboratory populations of D. melanogaster were surveyed by starch gel electrophoresis for variation at 17 enzyme loci. A single-fly extract could be assayed for all 17 enzymes, so that the data consist of 17-locus genotypes.——Pairwise linkage disequilibria were estimated from the multilocus genotypic frequencies, using both Burrows' and Hill's methods. Large amounts of linkage disequilibrium were found, in contrast to the results reported for natural populations.—Knowledge of the approximate sizes of these populations was used to compare the observed heterozygosities and linkage disequilibria with predictions of the neutral allele hypothesis. The relatively large amount of linkage disequilibrium is consistent with the small sizes of the populations. However, the levels of heterozygosity in at least some populations suggest that some mechanism has been operating to retard the rate of decay by random drift. Several examples of significant deviation from Hardy-Weinberg frequencies and the large amount of linkage disequilibrum present in these populations indicate that a likely mechanism is selective effects associated with neutral alleles because of linkage disequilibrium with selected loci (e.g., "associative overdominance"). The results are therefore consistent with both neutralist, and selectionist hypotheses, but suggest the importance of considering linkage disequilibrium between neutral and selected loci when attempting to explain the dynamics of enzyme polymorphisms.
TL;DR: Simple methods have been developed using the specific inhibitor, 3-amino-1,2,4-triazole, for the direct analysis of rates of synthesis and degradation of the Cat(+) gene product and it is suggested that these techniques can be readily applied to an examination of mutants that control the expression of the structural gene for catalase in Drosophila.
Abstract: A screen for allelic variants of the enzyme catalase indicated that the Cat + locus is essentially monomorphic in D. melanogaster . Segmental aneuploidy was used to screen the genome for a dosage-sensitive region for catalase activity. One region, 75D-78A on the polytene chromosome map of 3L, exhibited a hyperploid/euploid ratio of enzyme activity of 1.5. Further dissection localized the region to 75D-76A. We suggest that this region contains the structural locus for catalase in D. melmogaster . Simple methods have been developed using the specific inhibitor, 3-amino-1,2,4-triazole, for the direct analysis of rates of synthesis and degradation of the Cat + gene product. Based on kinetic studies of catalase synthesis in flies aneuploid and euploid for region 75D-76B, we suggest that these techniques can be readily applied to an examination of mutants that control the expression of the structural gene for catalase in Drosophila.