Showing papers by "North Carolina State University published in 1969"

On territorial behavior and other factors influencing habitat distribution in birds

Abstract: This example is provided so that non-theorists may see actual applications of the theory previously described. The Dickcissel sex ratio is employed as an indirect index of suitability. A sex ratio index was found to be correlated positively with density. This is consistent with the hypothesis that territorial behavior in the males of this species limits their density. This study provides a valid example of how the problem can be approached and offers a first step in the eventual identification of the role of territorial behavior in the habitat distribution of a common species.

Variance of gene frequencies.

Abstract: Inbreeding, gene frequency variance, and their corresponding effective population numbers are now commonplace terms in population genetics. The concepts and much of the theory are classical (Wright, 1921, 1931; Fisher, 1930). More recent refinements and extensions of the theory by Crow and associates (Crow, 1954; Crow and Morton, 1955; Kimura and Crow, 1963a, b) have been primarily concerned with distinguishing between the inbreeding effect on heterozygosity and on the variance of gene frequencies which are so intimately connected in finite populations. The purpose of the present paper is to relate the two in a way which the author thinks is meaningful and easy to grasp. Further, correlational measures are made compatible with probability measures of identity by descent and a simple basis is provided for the analysis of the variance of gene frequencies in experimental or natural populations. The procedure is to work with the variance of a linear function and to incorporate the role that the inbreeding and coancestry of individuals play in this variance. First, let us develop this role. We let aij index the jth allele in the ith individual and introduce a measure of frequency xij defined by

Respiration Corrections for Bacterial Uptake of Dissolved Organic Compounds in Natural WATERS1

Abstract: The uptake of 14C-labeled organic compounds has been used by many workers to study heterotrophic microorganisms in natural waters. However, if flux rates of organic compounds are to be measured, the loss of 14CO2 during incubation becomes an important source of error. A method is proposed in which the experiment is run in a closed system and the 14CO2 collected after killing and acidification. Phenethylamine on chromatographic paper is the absorbing agent and the paper is counted by liquid scintillation. Studies of 19 compounds from pond water showed that 60% (aspartic acid) to 8% (arginine) of the labeled material entering the microorganisms was respired.

Mass Rearing of the Tobacco Hornworm. II. Larval Rearing and Pupation

Abstract: A procedure for rearing Manduca sexta (Johannson) in a simple and effective manner is described, and its use in a mass rearing program is considered. The procedure is an open, nonsterile system in which larvae are reared collectively in trays and synchrony of development is manipulated by means of photoperiods. The ingredients of an artificial diet, a diagram of the rearing tray, the yield at various stages of growth, and aspects of the behavior of the larvae also are provided.

Federal Policy, Banking Market Structure, and Capital Mobilization in the United States, 1863–1913

Abstract: The success with which capital funds are mobilized and transferred to industrial and related activities is widely regarded as a critical determinant of both the timing and the pace of industrialization in the modern era. Gerschenkron, for example, has suggested that institutional developments which increased this type of capital mobility played an important role in the varying degrees of industrial progress of nineteenth-century European countries. A functionally similar development, resulting from government intervention at the time of the Civil War, occurred in American banking and provided a powerful capital-supply stimulus for the United States's postbellum industrialization. This study deals with the origins of this banking development, presents an analysis of its potential effects on patterns of capital movement, and tests the hypotheses arrived at in the theoretical analysis using banking data derived primarily from the Reports of the Comptroller of the Currency.

Glucose catabolism in Rhizobium japonicum.

Abstract: Gluconate catabolism in Rhizobium japonicum ATCC 10324 was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Specifically labeled gluconate gave the following results for growing cells, with values expressed as per cent 14CO2 evolution: C-1 = 93%, C-2 = 57%, C-3 = 30%, C-4 = 70%, C-6 = 39%. The preferential release of 14CO2 from C-1 and C-4 indicate that gluconate is degraded primarily by the Entner-Doudoroff pathway but the inequalities between C-1 and C-4 and between C-3 and C-6 indicate that another pathway(s) also participates. The presence of gluconokinase and a system for converting 6-phosphogluconate to pyruvate also indicate a role for the Entner-Doudoroff pathway. The extraordinarily high yield of 14CO2 from C-1 labeled gluconate suggests that the other participating pathway is a C-1 decarboxylative pathway. The key enzyme of the pentose phosphate pathway, 6-phosphogluconate dehydrogenase, could not be demonstrated. Specifically labeled 2-ketogluconate and 2,5-diketogluconate were oxidized by gluconate grown cells and gave ratios of C-1 to C-6 of 2.73 and 2.61, respectively. These compare with a ratio of 2.39 obtained with specifically labeled gluconate. Gluconate dehydrogenase, the first enzyme in the ketogluconate pathway found in acetic acid bacteria, was found. Oxidation of specifically labeled pyruvate, acetate, succinate, and glutamate by gluconate-grown cells yielded the preferential rates of 14CO2 evolution expected from the operation of the tricarboxylic acid cycle. These data are consistent with the operation of the Entner-Doudoroff pathway and tricarboxylic acid cycle as the primary pathways of gluconate oxidation in R. japonicum. An ancillary pathway for the initial breakdown of gluconate would appear to be the ketogluconate pathway which enters the tricarboxylic acid cycle at α-ketoglutarate.

Minimum Cost Quality Control Tests

Abstract: An expected cost model of a process whose mean is controlled by an X chart is developed. A two-stage numerical procedure is used to calculate the sample size, the number of units produced between samples, and the control limits of optimal control charts. Optimal plans are tabulated for three values of the a priori distribution parameter and three values of each of the three cost coefficients.

Consolidation Under Constant Rates of Strain

Abstract: Consolidation tests on three materials were conducted by inducing six different constant rates of strain on the samples. The total load on the sample, the pore pressure at the base and the deformation were measured. A theoretical solution was developed to enable the determination of the coefficient of consolidation, the compression index, and the preconsolidation pressure from this testing procedure. Within established limits, it is shown that the consolidation parameters determined by this method agree with parameters determined by the conventional testing method. The advantages of the proposed procedure are that a much shorter time is required to determine the consolidation parameters and that this procedure can be used to study the strain rate sensitivity of cohesive soils to consolidation loads.

Application of a damped spring-mass human vibration simulator in vibration testing of vehicle seats

Abstract: There is a need for standardized methods for testing vehicle seats. Such methods would allow for the direct comparison of the merits of seats of diverse types and designs. At the present time standardized testing procedures are not possible because the dynamic characteristics of the human subjects occupying the seat during testing vary widely from man to man and affect the seat response. Testing with dead weight loading does not accurately portray the dynamic characteristics of the seat. A damped spring-mass system closely approximating to the dynamic characteristics of a seated man to vertical modes of vibration has been developed as the basis on which a standardized vehicle seat testing procedure can be built. Analysis of the problem by means of mechanical impedance techniques indicated that a two-degree-of-freedom system was sufficient to simulate the major dynamic characteristics of man in the frequencies below 10 Hz where seat vibration is most severe. Test procedures have been developed whi...

Divergent Metabolic Pathways for Propane and Propionate Utilization by a Soil Isolate

Abstract: The metabolism of propane and propionate by a soil isolate (Brevibacterium sp. strain JOB5) was investigated. The presence of isocitrate lyase in cells grown on isopropanol, acetate, or propane and the absence of this inducible enzyme in n-propanol- and propionate-grown cells suggested that propane is not metabolized via C-terminal oxidation. Methylmalonyl coenzyme A mutase and malate synthase are constitutive in this organism. The incorporation of (14)CO(2) into pyruvate accumulated during propionate utilization suggests that propionate is metabolized via the methyl-malonyl-succinate pathway. These results were further substantiated by radiorespirometric studies with propionate-1-(14)C, -2-(14)C, and -3-(14)C as substrate. Propane -2-(14)C was shown, by unlabeled competitor experiments, to be oxidized to acetone; acetone and isopropanol are oxidized in this organism to acetol. Cleavage of acetol to acetate and CO(2) would yield the inducer for the isocitrate lyase present in propane-grown cells.

The Races of Maize: III. Choices of Appropriate Characters for Racial Classification'

Abstract: Analyses of variance for 111 characters from 55 races and subraces of maize from eastern South America grown at Piracicaba, S. P., Brazil, between 1960 and 1965, indicated that those characters which were least affected by environmental factors and interactions were reproductive characters. In particular, the component of variance due to differences among races for certain ear and kernel characters was greater than the sum of the corresponding components due to differences among years and race by year interactions. The converse was true for all vegetative characters. Tassel characters tended to be intermediate between ear and plant characters. While some indices had larger components of variance attributable to racial differences than to the effects of environment and/or environmental interaction, some commonly used ones, such as cob/rachis and rachilla/kernel indices, proved to be quite susceptible to environmental influences. Again, indices based upon solely vegetative characters were consistently influenced more strongly by environmental factors and interaction than were those based on reproductive characters.

Reducing inequity by reallocating rewards

Abstract: The equity model can predict the manner in which members of a dyad allocate among themselves the rewards earned by their group. Among members with equal work inputs, Ss given more than half the reward reduced inequity by decreasing their own share. Those given less than half the reward increased their share. Ss also reduced inequity by planning to compensate for current inequities in future interaction. As expected, level of tension covaried with the magnitude of inequity. Underrewarded Ss overestimated their inputs in order to justify increasing their share.

Tables for the Mean Square Error Test for Exact Linear Restrictions in Regression

Abstract: A table is presented containing critical points for the non-central F with non-centrality of one-half for type one error .05, .10, .25 and .50 and numerator and denominator d.f. including 1–30, 40, 60, 120, 200, 400, 1000. The critical points may be used to test the hypothesis that a set of exact linear restrictions imposed on the parameters of a linear model yield estimators that are better in generalized MSE than the unrestricted, o.l.s., estimators. Tabulation is discussed and some examples are presented on how the tables may be used.

Factors determining the selection of plants for oviposition by the tobacco hornworm manduca sexta

Abstract: A generalized scheme concerning the oviposition behavior of Manduca sexta (Johan.) moths was constructed according to observations and experiments conducted in large cages. There are two phases in the orientation to plants, the approach and the landing. The approach appears non-discriminatory and the moths utilize visual cues during this phase. The landing is discriminatory and is based on fixed or learned responses to olfactory stimuli. After landing, contact chemostimulation elicits deposition of eggs. ZUSAMMENFASSUNG DIE FUR DIE WAHL DER EIABLAGEPFLANZEN DES TABAKSCHWARMERS, MANDUCA SEXTA, BESTIMMENDEN FAKTOREN Auf Grund von Beobachtungen und Versuchen in grosen Kafigen wird ein allgemeines Schema des Eiablageverhaltens von Manduca sexta (Johan.) entvforfen. Es bestehen zwei Phasen in der Orientierung auf die Pflanzen, die Annaherung und die Landung. Die Annaherung scheint unterschiedslos ungerichtet zu erfolgen; die Schwarmer benutzen wahrend dieser Phase visuelle Schlusselreize. Die Landung ist entscheidend gerichtet und beruht auf erlernten Reaktionen auf spezifische Geruchsreize. Nach der Landung lost ein chemischer Kontaktreiz die Ablage der Eier aus.

Germination Response to Temperature and Salinity of Four Dune Grasses from the Outer Bank of North Carolina

Abstract: At four constant thermoperiods (65°, 75°, 85° and 95°F) and three alternating diurnal thermoperiods (65° —75°, 65° —95°F), good germination (above 70%) was obtained with seed of Ammophila breviligulata Fern., Panicum amarulum Hitch. and Chase., and Spartina patens (Ait.) Muhl. without cold treatment under certain temperature conditions. None of the constant temperature treatments yielded good germination. All attempts to obtain good germination with Uniola paniculata L. without cold treatment were unsuccessful. Various periods of cold treatment had no effect upon subsequent germination in the 65° —95°F alternating diurnal thermoperiod in A. brevilligulata and S. patens. In P. amarulum cold treatment for 15 days was sufficient to ensure good germination. Cold treatment for 30 days was adequate for good germination in U. paniculata, but 15 days was not always sufficient. When cold treatment for 30 days at 43°F preceded germination in the seven temperature conditions, germination was increased in all species. Maximum tolerance limits for A. breviligulata and U. paniculata to NaCl lie between 1.0% and 1.5%. The upper limit of NaCl concentration for germination of P. amarulum is between 1.5% and 2.0% and for S. patens about 4.0%. Germination response to salinity was primarily an inverse linear relationship for A. breviligulata, P. amarulum, and U. paniculata, but a curvilinear relationship in S. patens. In this species germination was successful at 2.0% NaCl. Germination inhibition in A. breviligulata, P. amarulum, and S. patens was apparently primarily an osmotic effect. Based on germination response, S. patens is the most salt tolerant, followed by P. amarulum which is more than U. paniculata. A. breviligulata is the most salt sensitive.

Isozyme genotype-environment relationships in natural populations of the harvester ant, Pogonomyrmex barbatus, from Texas.

Abstract: Three different allelic isozyme systems (two esterases, ESH and ESR, and a malic dehydrogenase, MDH) were analyzed in population samples of a species of ant, Pogonomyrmex barbatus, from Texas Allelic frequencies were determined for several collection localities, and a number of significant differences were found Principal component analysis was used to compare the patterns of variability of the allelic frequencies with environmental factors Significant correlation was particularly evident with respect to weather and the pattern of variability in both esterases, and it is therefore suspected that natural selection is important in determining the allele frequency patterns Observed and expected genotypic proportions were found in good agreement, generally, but in some localities homozygotes appeared in significantly greater numbers than expected Heterotic selective maintenance was thus not indicated Correlation found between patterns of variability in the enzyme systems themselves was consistent with the hypothesis that all three enzyme systems were affected by the environmental factors

The effect of penetrant activity and temperature on the anomalous diffusion of hydrocarbons and solvent crazing in polystyrene part I: Biaxially oriented polystyrene

Abstract: The effects of temperature and penetrant activity on the sorption kinetics and equilibria of a series of alkanes in glassy, biaxially oriented polystyrene were studied. Normal isomers of pentane, hexane, and heptane cause crazing of polystyrene film samples at high penetrant activities (> 0.85). Crazing kinetics are identical to the kinetics of Case II transport. Transport of these normal hydrocarbons in glassy polystyrene in the temperature range 25 to 50°C is markedly non-Fickian; limiting Case II transport is observed at activities in exces of 0.6. Sorption appears to be controlled by highly activated relaxation processes including primary bond breakage at these high penetrant activities. Fickian diffusion behavior is approached, however, as penetrant activity is reduced. Sorption of the branched isomers of these compounds does not result in polymer microfailure. The sorption kinetics of the branched isomers, although time dependent, appear to be controlled primarily by thermally activated diffusion rather than large scale polymer relaxations which control Case II transport.

The influence of ammonium on nitrate reduction in wheat seedlings.

Abstract: Ammonium markedly inhibited nitrate absorption by nitrogenstarved wheat seedlings but did not decrease the proportion of absorbed nitrate that was reduced. Seedlings high in nitrate (absorbed prior to the experimental periods) reduced similar amounts of this nitrate regardless of whether or not ammonium was present and being absorbed during the period of measurement. Ammonium or products of ammonium assimilation did not interfere with the induction, stability, or activity of nitrate reductase. Consequently, the hypothesis that ammonium depresses nitrate uptake indirectly by inhibiting nitrate reduction is rejected, and it is suggested that the ammonium effect is directly on the nitrateuptake process.

Regulation of staphylococcal enterotoxin B.

Abstract: Several factors influenced the formation of enterotoxin B by Staphylococcus aureus strain S-6. In the standard casein hydrolysate medium, toxin was not produced in detectable quantities during exponential growth; it was produced during the post-exponential phase when total protein synthesis was arithmetic. The rate of toxin synthesis was much greater than the rate of total protein synthesis. The appearance of enterotoxin was inhibited by chloramphenicol; thus, the presence of toxin was dependent on de novo protein synthesis. When low concentrations of glucose ( p H resulting from the acid end products of glucose metabolism. At p H p H above 5.6. In such media, the differential rates of toxin synthesis, with respect to the rates of total protein synthesis, were lower than the differential rates in casein hydrolysate medium alone. Addition of glucose to a culture synthesizing toxin resulted in an immediate decrease in the differential rate without any change in p H. Thus, toxin synthesis appeared to be regulated by catabolite repression.

Wetting of Binary Aluminum Alloys in Contact with Be, B4C, and Graphite

Abstract: Sessile drop contact angles between liquid aluminum alloys and solid beryllium, boron carbide, and graphite were measured to 840°C under vacuum and in helium. Little wetting occurred between most of the combinations, but at 20% magnesium the contact angle on beryllium decreased to 68°. Low contact angles were noted for the binary aluminum alloys on graphite coated with titanium.

Biological Response of Lactic Streptococci and Lactobacilli to Catalase

Abstract: Addition of catalase to milk cultures of lactic streptococci resulted in increased rates of acid production, although it had no effect on cultures of lactobacilli. Milk cultures of both streptococci and lactobacilli produced detectable amounts of peroxide, which reached a maximum level in the early period of acid production followed by a drastic decrease as the acid production increased. Pyruvate and reduced glutathione decreased the amount of peroxide formed, but had little effect on acid production by the streptococci. Ferrous sulfate prevented the accumulation of peroxide and stimulated the rate of acid production by the streptococci to a greater extent than did catalase.

Water transport and clustering in poly[vinyl cloride], poly[oxymethylene], and other polymers

Abstract: The diffusion constants for water vapor in poly (vinyl chloride) and poly(oxymethylene) have been determined by the time-lag method. In addition the sorption isotherms have been measured by direct weighing. The values of the solubility coefficient obtained gravimetrically have been compared with those calculated from the quotient of the permeability and diffusion constants obtained from the time lags. Quite different patterns of behavior were exhibited by the two polymers. In the case of poly(oxvmethylene) the two sets of values of the solubility coefficients were quite similar and fitted a normal Brunauer—Emmett-Teller (BET) type-III sorption isotherm. With poly(vinyl chloride), however, the solubilities calculated from P/D obeyed Henry's law and were considerably less than those obtained by direct weighing (except at low activities) which again were of the BET type III. These results were compared to those found with other polymers and have been interpreted in terms of the different degrees of ...

Theoretical investigations into the accuracy of sampling shelled peanuts for aflatoxin

Abstract: Within a population of shelled peanuts, aflatoxin may be concentrated in less than 0.5% of the peanuts. Those peanuts containing aflatoxin might have concentrations up to 1,000,000 µg of aflatoxin per kilogram of peanuts. Because of the distribution pattern, sample means vary widely, and the true average level of aflatoxin in the population is difficult to estimate. The objective of this study was to determine the effect of sample size, N, on sampling accuracy. The negative binomial distribution of aflatoxin since it allowed for a high probability of zero counts along with small probabilities of large counts. Using both the Monte Carlo technique and a direct computation method, the effect of sample size on sampling accuracy was quantitatively described.