scispace - formally typeset
Search or ask a question

Showing papers by "North Carolina State University published in 1972"


Journal ArticleDOI
01 Oct 1972-Genetics
TL;DR: That these mutants have a disproportionately large heterozygous effect on total fitness (as well as on the viability component thereof) is shown by the low ratio of the genetic load in equilibrium homozygote to that of new mutant homozygotes.
Abstract: Spontaneous mutations were allowed to accumulate in a second chromosome that was transmitted only through heterozygous males for 40 generations. At 10-generation intervals the chromosomes were assayed for homozygous effects of the accumulated mutants. From the regression of homozygous viability on the number of generations of mutant accumulation and from the increase in genetic variance between replicate chromosomes it is possible to estimate the mutation rate and average effect of the individual mutants. Lethal mutations arose at a rate of 0.0060 per chromosome per generation. The mutants having small effects on viability are estimated to arise with a frequency at least 10 times as high as lethals, more likely 20 times as high, and possibly many more times as high if there is a large class of very nearly neutral mutations.—The dominance of such mutants was measured for chromosomes extracted from a natural population. This was determined from the regression of heterozygous viability on that of the sum of the two constituent homozygotes. The average dominance for minor viability genes in an equilibrium population was estimated to be 0.21. This is lower than the value for new mutants, as expected since those with the greatest heterozygous effect are most quickly eliminated from the population. That these mutants have a disproportionately large heterozygous effect on total fitness (as well as on the viability component thereof) is shown by the low ratio of the genetic load in equilibrium homozygotes to that of new mutant homozygotes.

481 citations


Journal ArticleDOI
TL;DR: After demonstrating the existence of nontrivial information Jossless parallel maps on one-dimensional iterative array configurations, algorithms are presented for deciding the injectivity or surjectivity of the global maps given their defining local maps.

255 citations


Journal ArticleDOI
TL;DR: The total water exchange through part of the West Atlantic shelf is computed and the influence of the phenomenon is discussed from a biological point of view and with regard to its importance for the world's oceans.
Abstract: Sandy subtidal sediments are part of the earth's largest filter system. Water flow through bottom sediments is driven by wave action on the sea surface. The mechanisms involved are described, including a theoretical deduction and field measurements. As an example, the total water exchange through part of the West Atlantic shelf is computed and the influence of the phenomenon is discussed from a biological point of view and with regard to its importance for the world's oceans.

234 citations


Journal ArticleDOI
TL;DR: The optimum (minimum mean-squared-error) and optimum uniform quantizing characteristics for Laplacian- and gamma-distributed signals are given in tabular form and the performance of these quantizers in real speech pulse-code modulation and differential pulse- code modulation systems is investigated and compared with that obtained when the μ-law quantizing characteristic is used.
Abstract: The optimum (minimum mean-squared-error) and optimum uniform quantizing characteristics for Laplacian- and gamma-distributed signals are given in tabular form. The performance of these quantizers in real speech pulse-code modulation (PCM) and differential pulse-code modulation (DPCM) systems is investigated and compared with that obtained when the μ-law quantizing characteristic is used.

200 citations


Journal ArticleDOI
TL;DR: A self-mapping T of a subset C of a normed linear space is said to be non-expansive provided T holds for all x, y ∈ C.
Abstract: A self-mapping T of a subset C of a normed linear space is said to be non-expansive provided ║Tx — Ty║ ≦ ║x – y║ holds for all x, y ∈ C. There has been a number of recent results on common fixed points of commutative families of nonexpansive mappings in Banach spaces, for example see DeMarr [6], Browder [3], and Belluce and Kirk [1], [2]. There have also been several recent results concerning common fixed points of two commuting mappings, one of which satisfies some condition like nonexpansiveness while the other is only continuous, for example see DeMarr [5], Jungck [8], Singh [11], [12], and Cano [4]. These results, with the exception of Cano's, have been confined to mappings from the reals to the reals. Some recent results on common fixed points of commuting analytic mappings in the complex plane have also been obtained, for example see Singh [13] and Shields [10].

153 citations


Journal ArticleDOI
TL;DR: The dorsal organs of the cephalic lobes of the house fly larva were studied by light, scanning and transmission electron microscopy, indicating the possibility of additional undescribed receptors.
Abstract: The dorsal organs of the cephalic lobes of the house fly larva, Musca domestica L. were studied by light, scanning and transmission electron microscopy. Five types of receptors were found in the distal part of the dorsal organ: (1) The dome, whose ultrastructure is similar to that of thin-walled pegs, is assumed to be an olfactory receptor. (2) A lateral pore receptor, with the distal tips of two dendrites exposed to the exterior through a pore, is presumed to be a contact chemoreceptor. (3) A scolopidium-like receptor, with an ultrastructure characteristic of a scolopidium receptor except that the dendrite might be exposed to the exterior through an opening, is assumed to be both a mechanoreceptor and contact chemoreceptor. (4) Two receptors, each with one of its two dendrites exposed to the exterior, are probably contact chemoreceptors. (5) Two unclassified receptors, each with one dendritic tip exposed to the exterior and the other dendrite with a tubular body ending near the pore, may serve as both contact chemoreceptors and mechanoreceptors. The last four types are located in the invagination between the dome and the cylindrical portion of the dorsal organ. The seven basal pores of the dome are apparently points of origin of the scolopales and have no sensory function. The dorsal organ is supplied by 35–41 bipolar neurons, indicating the possibility of additional undescribed receptors.

133 citations


Journal ArticleDOI
TL;DR: In this article, a replacement principle is derived which applies to both appreciating assets such as forests and depreciating assets, such as equipment, and the resulting replacement criterion provides a definition of opportunity costs appropriate for the replacement decision.
Abstract: Using a general model of asset replacement, a replacement principle is derived which applies to both appreciating assets such as forests and depreciating assets such as equipment. The resulting replacement criterion provides a definition of opportunity costs appropriate for the replacement decision. The theory is presented graphically for the continuous time case, and two discrete-time examples are considered. Theoretical implications of changing discount rates and market forces are considered as they affect replacement policies.

131 citations


Journal ArticleDOI
TL;DR: In this paper, living mass and respiratory rate were estimated by several methods on large water samples taken at several depths at each of two ocean stations, at both surface and deep water.
Abstract: Estimates of living mass and respiratory rate were made by several methods on large water samples taken at several depths at each of two ocean stations. Total microbial biomass estimates based on ATP determinations gave reasonable results in relation to phytoplankton biomass, total particulate organic carbon, and total particulate volume as determined by an electronic particle counter. Respiratory rate estimates based on 0, uptake, electron transport system activity, and ATP were in moderately good agreement in surface water but diverged widely in deep water. Heterotrophic uptake of specific organic compounds seems to be related to numbers of active bacteria and not related to total microbial respiration. Photosynthetic rates and release of dissolved photosynthate are reported for both stations.

114 citations


Book
01 Jan 1972
TL;DR: The impact of uncertainty on location patterns has been studied in a wide range of areas, such as the effect of duopolists, the patterns of towns, the production decisions of firms and the impact of widespread innovations on location as mentioned in this paper.
Abstract: Until now, the effects of uncertainty on location patterns have remained largely unexplored. Theories about the way in which firms make decisions to locate have long been restricted by the assumption that they know all the relevant facts when the decisions are made. This book attempts to generalize location theory to take account of the fact that the opposite is more often the case--firms are uncertain when they make their decisions.Taking a theoretical rather than empirical approach to the problem, the book discusses such topics as the location of duopolists, the patterns of towns, the production decisions of firms, and the impact of widespread innovations on location. In addition, it contains a collection of largely independent models that need to be more fully tested and combined into a mathematical theory.Walter Isard writes in his foreword that "regardless of the viewpoint to which the reader is sympathetic, he will find the Webber book to be an important contribution to location theory. It does a fine job of surveying and critically evaluating, in a consistent analytical manner, many of the advances during the last fifteen years of rapid growth of location theory; consequently, location students can now obtain a better view of the field as a whole. More important, this book goes beyond a critical analytical survey. It focuses attention on an area seriously neglected by location theorists, namely the impact of uncertainty upon location decisions and spatial patterns. Webber states the case for studying this impact. It is a sound case. Further, Webber is not misled about his contribution. He modestly views his book as 'a preliminary account of one direction in which new location theory may profitably evolve."The book is a volume in the MIT Regional Science Studies Series, of which Walter Isard is General Editor.

113 citations


Journal ArticleDOI
TL;DR: The data suggest that lipid transport is a primary lesion during aflatoxicosis in the chicken and is not secondary to the general effects on nucleic acid metabolism.

112 citations


Journal ArticleDOI
TL;DR: The standard diagnostic test for differentiating staphylococci from micrococci is modified to provide greater convenience, easier interpretation of results, and better correlation with deoxyribonucleic acid (DNA) base composition, and observations suggest some interesting genetic and metabolic capabilities in such cultures.
Abstract: The standard diagnostic test for differentiating staphylococci from micrococci is based on the ability of the former to produce acid anaerobically in a glucose-containing growth medium. This test has been modified to provide greater convenience, easier interpretation of results, and better correlation with deoxyribonucleic acid (DNA) base composition. In the modified test, shake cultures in Brewer's fluid thioglycolate medium with 0.3% agar added are observed for growth in the anaerobic zone of the tubes. This test was applied to 125 strains of staphylococci and micrococci, and all except two strains gave results that were consistent with other criteria. Of particular interest were eight strains of Micrococcus saprophyticus and three strains of M. lactis that have a DNA composition of 30 to 37% guanine plus cytosine (GC). All 11 of these cultures produced anaerobic growth and thus would be classified as staphylococci. Strains of M. lactis that have a high GC content in their DNA grew only aerobically. Some cultures of staphylococci produced characteristic band patterns of anaerobic growth and other cultures produced only a few anaerobic colonies from an inoculum of 10(6) to 10(7) cells. These observations suggest some interesting genetic and metabolic capabilities in such cultures.

Journal ArticleDOI
TL;DR: The data suggest that the role of fusariotoxin T-2 in field cases of moldy corn toxicosis should be reinvestigated since oral lesions were not mentioned in the original descriptions of the disease.
Abstract: Fusariotoxin T-2 is a mycotoxin produced by Fusarium tricinctum which was implicated in moldy corn toxicosis of farm animals. Graded concentrations of dietary fusariotoxin T-2 (0, 1, 2, 4, 8, and 16 μg/g, respectively) were given to groups of 40 chickens. Raised yellowish-white lesions on the mouth parts were produced by all concentrations, and the size of the lesions was dose-related. The growth rate was reduced significantly (P < 0.05) by concentrations of 4, 8, and 16 μg/g. The mouth fluid of the affected birds contained greatly increased numbers of bacteria, including Staphylococcus epidermidis and Escherichia coli, which proved avirulent when inoculated into scarified tissue of control birds. Microscopy examinations of the lesions revealed a fibrinous surface layer, intermediate layers containing invaginations filled with rods and cocci, and a heavy infiltration of the underlying tissues with granular leukocytes. These data suggest that the role of fusariotoxin T-2 in field cases of moldy corn toxicosis should be reinvestigated since oral lesions were not mentioned in the original descriptions of the disease. However, the lesions bear some features of those characteristic of the third or septic angina stage of alimentary toxic aleukia, a nutritional toxicosis of humans produced by eating grains infested with F. tricinctum.


Journal ArticleDOI
TL;DR: A practical solution to the problems encountered in their deployment is suggested which combines two of the techniques (generalized distances and principal components) which are mathematically related in simple ways.
Abstract: Goodman, M. M. (Dept. of Statistics, North Carolina State University at Raleigh, North Carolina, 27607) 1972. Distance analysis in biology. Syst Zool., 21:174-186.-The mathematical relationships between generalized distances, Sokal's distances, distances based upon principal components, and C,avalli-Sforza and Edwards' chord distances are discussed, and the biological consequences of these relationships in the case of nontrivial correlation matrices are pointed out. While none of the techniques discussed are wholly satisfactory, a practical solution to the problems encountered in their deployment is suggested which combines two of the techniques (generalized distances and principal components). [Principal components; Sokal distance; generalized distance.] Both numerical and noni-numerical taxoniomists as well as anthropologists and other quantitatively oriented scientists have employed several types of distance analyses based on morphological data (Sokal and Sneath, 1963). More recently similar techniques have also been used in the analyses of human blood group frequencies (CavalliSforza and Edwards, 1967; Pollitizer, 1958, 1969; Pollitzer et al., 1967, 1970; Fitch and Neel, 1969). In addition, principal component analyses are frequently utilized in conjunction with, or as an alternative to, such techniques (Gower, 1966; Morrison, 1967). Certain of these techniques are mathematically related in simple ways which are both biologically important and generally unfamiliar.

Journal ArticleDOI
TL;DR: The in vivo administration of piperonyl butoxide or propyl isome to mice affects the levels of several hepatic cytochrome P-450 spectral interactions, and the ethyl isocyanide (EtNC) equilibrium point undergoes a biphasic shift.

Journal ArticleDOI
TL;DR: Pyrenebutyric acid is examined as a possible fluorescent probe to determine intracellular concentrations of oxygen, and this technique appears to be applicable to the physiological range of oxygen concentrations.

Journal ArticleDOI
TL;DR: Examination of type I and type II substrate difference spectra indicate that induction at higher levels was not only greater but that the cytochrome induced was qualitatively different from that induced at lower levels.

Journal ArticleDOI
TL;DR: In this article, the critical load for flutter was found independent of the foundation modulus, which characterizes the Winkler-type elastic imbedding, and the frequency of vibration of the beam increases with increasing base modulus but the magnitude of critical load is not affected.
Abstract: Discussion of a new aspect in the behavior of a cantilevered beam on an elastic foundation subjected to a follower force at its free end. The critical load for flutter is found to be independent of the foundation modulus which characterizes the Winkler-type elastic imbedding. The frequency of vibration of the beam increases with increasing foundation modulus, but the magnitude of the critical load is not affected. This result is valid for any 'tangency coefficient' value.

Journal ArticleDOI
TL;DR: In this article, semi-empirical potentials are constructed that have eigenvalues close in magnitude to the binding energies of the valence electron in lithium and the corresponding eigenfunctions are used to calculate dynamic polarizabilities, discrete oscillator strengths, photoionization cross sections and radiative recombination coefficients.
Abstract: Semi-empirical potentials are constructed that have eigenvalues close in magnitude to the binding energies of the valence electron in lithium The potentials include the long range polarization force between the electron and the core The corresponding eigenfunctions are used to calculate dynamic polarizabilities, discrete oscillator strengths, photoionization cross sections and radiative recombination coefficients A consistent application of the theory imposes a modification on the transition operator, but its effects are small for lithium The method presented can be regarded as a numerical generalization of the widely used Coulomb approximation

Journal ArticleDOI
TL;DR: The fine structure of Haller's organ supports the functions postulated by Lees (1948), namely olfaction for the capsule and humidity reception (among others) for the anterior pit.
Abstract: Haller's organ on the tarsus of the tick Amblyomma americanum (L.) (Acarina: Ixodidae; nymphal stage) was studied by scanning and transmission electron microscopy. It consists of a distal bristle group, (the “anterior pit”), and a proximal “capsule” which encloses several sensilla. The seven sensilla of the anterior pit (A1–A7) are all thick-walled and multi-innervated (2–9 neurons), but at least three different types can be differentiated. Sensilla A1 and A2 possess large, plugged pores (>1000 A) and are the only sensilla with branching dendrites. A3 and A5 are characterized by a spoke-wheel arrangement of the cuticle wall and very fine pores (100–200 A) penetrating the “spokes” centrally; A4, A6, and A7 do not exhibit any pore system but a single opening at the bristle tip is assumed.

Journal ArticleDOI
TL;DR: In this article, an experimental investigation is presented for the drying of absorbent materials (such as cotton) with the aid of microwave heating, and data for the transient temperature, pressure, and moisture distributions for axial, radial and combined axial and radial drying are presented.

Journal ArticleDOI
04 Aug 1972-Science
TL;DR: The comments of the Commissioners as published show a deep schism within the Commission on the validity of the actions taken on this Declaration, and it is unfortunate that Mayr and his colleagues have not made this schism clear in their statement because it will be read and acted upon by many who have no access to the Declaration itself.
Abstract: publication. Several of the Commissioners objected to the inclusion of this vote with the Declaration because they did not consider it official, and this presumably forms the basis for the statement in Mayr et al. (1) concerning the vote. However, the issue was submitted a second time to the Commission, asking if they approved the publication of the vote, and the ballot on this question was 17 to 5 in favor. The comments of the Commissioners as published show a deep schism within the Commission on the validity of the actions taken on this Declaration, and we consider it unfortunate that Mayr and his colleagues have not made this schism clear in their statement because it will be read and acted upon by many who have no access to the Declaration itself. If the opinions of the majority of the Commissioners are to be accepted, one cannot accept the minority opinion expressed by Mayr et al. Mayr et al. state, as if 'a fait accompli, that the Commission cannot repeal Art. 23(b). However, in the history following Declaration 43, it is clear that the legal adviser to the Commission, the Secretary, and some Commissioners do believe that the Commission has the authority to delete or suspend parts of the Code, such as Art. 23(b). The important question for the working taxonomist is, if the Commission does have this authority, did they in fact repeal or suspend Art. 23(b). As defined by Art. 78 of the Code, a Declaration is a provisional amendment to the Code. It is to be issued by the Commission in a case that \"involves a situation that is not properly or completely covered by the Code,\" and this Declaration remains in force until the next succeeding Congress ratifies or rejects it. We believe that the Commission did suspend Art. 23(b) until the next International Congress of Zoology this summer and that zoologists who are seeking to preserve well-established names must apply to the Commission to preserve them under the plenary powers. BRUCE B. COLLETTE DANIEL M. COHEN National Marine Fisheries Service, Systematics Laboratory, National Museum of Natural History, Washington, D. C. 20560 JAMES A. PETERS Division of Amphibians and Reptiles, National Museum of Natural History, Washington, D. C. 20560


Journal ArticleDOI
TL;DR: In this paper, a Hardin oscillator was used to apply a steadystate, torsional vibratory load to remolded specimens of kaolinite and calcium bentonite inside a triaxial chamber and under an isotropic consolidation pressure.
Abstract: A Hardin oscillator was used to apply a steady-state, torsional vibratory load to remolded specimens of kaolinite and calcium bentonite inside a triaxial chamber and under an isotropic consolidation pressure The principles of the resonant column test were used to determine the dynamic shear modulus After completion of primary consolidation, the response was studied as a function of time for both drained and undrained conditions Regression analyses were performed on these data and relationships are presented which show the effects that void ratio, effective stress, and time have on the dynamic response of these two clays The shear modulus was shown to increase with increasing pressure, decreasing void ratio and time for both materials This increase was approximately 10% of kaolinite and 40% for bentonite per logarithmic cycle of time after completion of primary consolidation for constant effective stress

Journal ArticleDOI
TL;DR: In this article, the effects of single scattering albedo, optical thickness, and conduction-to-radiation parameter on temperature distribution in the boundary layer and heat transfer at the wall were investigated.

Journal ArticleDOI
TL;DR: Growth of salmonellae and staphylococci is retarded in foods cultured with lactic streptococci since pathogens can be repressed even when the milk is maintained at pH 6.6 during starter growth.
Abstract: The lactic streptococci have been utilized to produce certain fermented foods for many years. In addition to producing a cultured food having new characteristics, these organisms aid in preserving the food. Growth of salmonellae and staphylococci is retarded in foods cultured with lactic streptococci. This antagonistic action is caused by factors in addition to the acidic environment created by the streptococci since pathogens can be repressed even when the milk is maintained at pH 6.6 during starter growth. The intensity of the antagonistic action cannot be predicted by the rate at which acid is produced by the streptococci.

Journal ArticleDOI
26 Jan 1972-Nature
TL;DR: A correlated programme of study of the ultrastructural and behavioural development of the embryonic nervous system of birds.
Abstract: RECENT advances in the study of the ontogeny of neural function in the chick embryo1 have re-emphasized the need for a better understanding of the morphological details of the developing avian nervous system. With this in mind we have undertaken a correlated programme of study of the ultrastructural and behavioural development of the embryonic nervous system of birds.

Journal ArticleDOI
TL;DR: Inorganic phosphate, with or without MgSO4, was able to facilitate repair in phosphate and the rate of repair was rapid and maximum in a complex nutrient medium such as Trypticase soy broth supplemented with yeast extract.
Abstract: Freezing an aqueous suspension of Escherichia coli NCSM at -78 C for 10 min, followed by thawing in water at 8 C for 30 min, resulted in the death of approximately 50% of the cells, as determined by their inability to form colonies on Trypticase soy agar containing 0.3% yeast extract (TSYA). Among the survivors, more than 90% of the cells were injured, as they failed to form colonies on TSYA containing 0.1% deoxycholate. Microscope counts and optical density determinations at 600 nm suggested that death from freezing was not due to lysis of the cells. Death and the injury were accompanied by the loss of 260- and 280-nm absorbing materials from the intracellular pool. Injury was reversible as the injured cells repaired in many suitable media. The rate of repair was rapid and maximum in a complex nutrient medium such as Trypticase soy broth supplemented with yeast extract. However, inorganic phosphate, with or without MgSO(4), was able to facilitate repair. Repair in phosphate was dependent on the pH, the temperature, and the concentration of phosphate.

Journal ArticleDOI
TL;DR: The null hypothesis that each of the true unknown distribution functions was negative binomial was not rejected at the 5% significance level for all 29 comparisons and the functional relationship betweenk andm was indicated to be:k=(2.0866+2.3898m) × 10−6.
Abstract: Suitability of the negative binomial distribution for use in estimating the probabilities associated with sampling lots of shelled peanuts for aflatoxin analysis has been studied. Large samples, called “minilots,” were drawn from 29 lots of shelled peanuts contaminated with aflatoxin. These minilots were subdivided into ca. 12 lb samples which were analyzed for aflatoxin. The mean and variance of these aflatoxin determinations for each minilot were determined. The shape parameterk and the mean aflatoxin concentrationm were estimated for each minilot. A regression analysis indicated the functional relationship betweenk andm to be:k=(2.0866+2.3898m) × 10−6. The observed distribution of sample concentrations from each of the 29 minilots was compared to the negative binomial distribution by means of the Kolmogorov-Smirnov test. The null hypothesis that each of the true unknown distribution functions was negative binomial was not rejected at the 5% significance level for all 29 comparisons.

Journal ArticleDOI
TL;DR: Combinational networks with no internal fan-out are considered from the point of view of testing for multiple faults.
Abstract: Combinational networks with no internal fan-out are considered from the point of view of testing for multiple faults. Several different approaches utilizing added inputs and observable outputs are considered and the tradeoffs are discussed.