Showing papers by "University of Maine published in 1970"
TL;DR: The chromosomes of sea-run Atlantic Salmon from three North American rivers were studied with cell culture preparations and a relatively constant arm number of 72 indicates a Robertsonian pattern of polymorphism.
Abstract: The chromosomes of sea-run Atlantic Salmon from three North American rivers were studied with cell culture preparations. Extensive data from Machias River (Maine) specimens showed a sharp mode of 54 chromosomes. Modes of 55 for the Narraguagus River (Maine) and 56 for the Miramichi River (New Brunswick) represented much smaller percentages of their counts. A relatively constant arm number of 72 indicates a Robertsonian pattern of polymorphism.
64 citations
TL;DR: In this article, a decrease in the concentration of a sucrose solution resulted in negative incentive contrast effects, and this finding disagrees with many studies in the literature, such as this article.
Abstract: A decrease in the concentration of a sucrose solution resulted in negative incentive contrast effects. This finding disagrees with many studies in the literature.
62 citations
TL;DR: In this paper, a four-parameter rigid ion model utilizing an effective ionic charge was used for the determination of phonon dispersion, phonon density of states, and the Debye characteristic temperature of ZnTe.
Abstract: A four-parameter rigid-ion model utilizing an effective ionic charge is used for the determination of phonon dispersion, phonon density of states, and the Debye characteristic temperature of ZnTe. Structures in the infrared spectrum of ZnTe are assigned to multiphonon combinations of various critical-point phonon frequencies. Using the long-wavelength optic-mode phonon frequencies as well as the elastic constants and their respective pressure derivatives as input data, the mode Gr\"uneisen parameters, the Gr\"uneisen constant, and the coefficient of thermal expansion of ZnTe are calculated.
50 citations
TL;DR: In this paper, residue analysis of forest soils sprayed once at 1 lb/acre showed little breakdown of DDT through 9 years after application and suggested that this relationship may persist for as long as 30 years after a single application to the forest.
Abstract: Residue analysis of forest soils sprayed once at 1 lb/acre showed little breakdown of DDT through 9 years after application. In the absence of appreciable downward trend, residue persistence could not be estimated beyond stating that it appears to persist much longer than the 10 years suggested by others. Persistent residues are largely restricted to the upper soil litter. Residues pass from soils to earthworms to robins throughout the 9-year period studied. It is suggested that this relationship may persist for as long as 30 years after a single application to the forest. Biological magnification of residues in robins is demonstrated. Significance of these residue levels is discussed.
40 citations
TL;DR: In this paper, the HNC equation is solved for 1-1, 2-1 and 3-1 model electrolytes of charged hard spheres of radii 2.1 A. The anomalous behaviour of the osmotic coefficients and heats of dilution of 2-2 electrolytes, and oscillations in the charge density about a given ion for different charge types are discussed.
33 citations
TL;DR: In this paper, the phonon dispersion curves for CsCl, CsBr, and CsI have been obtained using a rigid-ion model with an appropriate effective ionic charge.
Abstract: The phonon dispersion curves for CsCl, CsBr, and CsI have been obtained using a rigid-ion model with an appropriate effective ionic charge. The five model parameters for each crystal are obtained from three elastic constants and the two long-wavelength optic-mode frequencies, reliable data for which exist for all three crystals. Our results are in agreement with those of more elaborate models. The phonon density of states and the Debye characteristic temperatures are also calculated. A Born-Mayer-type potential is used to calculate long-wavelength LO and TO mode frequencies as functions of pressure from pressure dependence of bulk modulus. The result for TO of CsBr agrees well with a recent experimental determination. Next, using the values of the elastic constants and LO and TO frequencies at various pressures, $\ensuremath{\omega}\ensuremath{-}\mathrm{v}\mathrm{e}\mathrm{r}\mathrm{s}\mathrm{u}\mathrm{s}\ensuremath{-}\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$ curves in selected directions are generated as functions of pressure. Mode Gr\"uneisen parameters are then calculated as functions of $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$. Finally, the Gr\"uneisen constant and the volume coefficient of thermal expansion are obtained as functions of temperature. They agree very well with available experimental data.
32 citations
TL;DR: A protoporphyrin was isolated from Euglena, and its role as a possible photoreceptor during carotenogenesis is suggested.
Abstract: Light induces beta-carotene synthesis in streptomycin-bleached Euglena gracilis Z Light-adapted, chemostat-grown cells have up to 10-fold as much beta-carotene and 25% more protein than similarly grown, dark-adapted cells Carotenogenesis does not occur under anaerobic conditions or in the presence of diphenylamine, cyanide, or cycloheximide The blue portion of the spectrum (360-560 nm) is most active in initiating carotenogenesis The level of cellular carotenoids is influenced by the type of carbon source and to some degree by pH Phytofluence and zeta-carotene are present in dark-grown cells but not in cells grown aerobically in white light (360-1120 nm) These pigments, however, were present in cells grown in yellow or green light (above 486 nm) or in cells exposed to white light anaerobically The carotenoids are localized in two types of structures at the light microscope level A protoporphyrin was isolated from Euglena, and its role as a possible photoreceptor during carotenogenesis is suggested
27 citations
TL;DR: It was shown that statistically significant differences in population density can usually be demonstrated within any series of collections when the collecting interval is more than 10 cm, and individual species in any series are in general over-dispersed.
Abstract: Analyses of phytoplankton collections from Narragansett Bay, Rhode Island and the Damariscotta River, Maine, USA showed that statistically significant differences in population density can usually be demonstrated within any series of collections when the collecting interval is more than 10 cm. Individual species in any series are in general over-dispersed. Phytoplankton patches ranging in size from <1 m to 12 m were tentatively identified. No correlation was found between temperature or salinity and the small-scale distribution of individual species. Possible causes of the inhomogeneities observed in phytoplankton distributions are considered.
26 citations
TL;DR: The enzyme is not active in cells grown with phototrophic nutrition, but is found in all heterotrophic cells grown on a wide range of carbon sources; the specific activity is greatly dependent on carbon source.
Abstract: SYNOPSIS. Properties of partially purified malate synthase from Euglena gracilis were characterized. The pH optimum is 7.0 and the temperature optimum about 30 C; the activation energy is 12,000 calories. A Km of 4 × 10−5 M was found for both reactants, glyoxylate and acetyl-CoA. The reaction is partially inhibited by a number of normal metabolites, suggesting allosteric control; glycolate is severely inhibitory. The enzyme is not active in cells grown with phototrophic nutrition, but is found in all heterotrophic cells grown on a wide range of carbon sources; the specific activity is greatly dependent on carbon source. High rates of oxygen consumption are usually, but not always, correlated with high enzyme levels.
20 citations
TL;DR: In this paper, the authors examined the properties of amorphous germanium and silicon in terms of the gross features of the (crystalline) band structure and the electron transport mechanism.
Abstract: Although considerable effort has gone into experimental studies of elemental amorphous semiconductors in recent years, four general questions remain only partially answered. Is the amorphous phase well-defined in these materials? Are the gross features of the (crystalline) band structure preserved? What is the nature of the localized (defect) states introduced by the disorder? What is the electron transport mechanism? These questions will be examined in the light of the experimental results, concentrating on amorphous germanium and silicon.
19 citations
TL;DR: It has been shown that glycine is absorbed at a site different from the neutral (methionine) transport site previously characterized in this species, and the glycine site has highest affinity for glycine, alanine, and other neutral amino acids, in that order.
01 Aug 1970
TL;DR: In this paper, the authors present a review of the synthysis of sulfinyl cylinders and their application in the field of organic preparation and procedures. But this review is limited.
Abstract: (1970). THE SYNTHESIS OF SULFINYL CHLORIDES. A REVIEW. Organic Preparations and Procedures: Vol. 2, No. 3, pp. 235-244.
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25 Nov 1970TL;DR: This article found that a decrease in amount of reinforcement resulted in negative incentive contrast effects, and this finding agrees with many studies involving animal Ss, such as the one of This article.
Abstract: A decrease in amount of reinforcement resulted in negative incentive contrast effects. This finding agrees with many studies involving animal Ss.
TL;DR: The cestode zoonoses of Diphyllobothrium, and Spirometra and Sparganosis are discussed from the point of view of their transmission and epidemiology.
Abstract: The cestode zoonoses of Diphyllobothrium, and Spirometra and Sparganosis are discussed from the point of view of their transmission and epidemiology.
TL;DR: In this paper, the reactions of (CH3)3SiCl and (CH 3)2NNO with NOCl have been studied, and the products observed are, respectively, (CH, 3SiOSi(CH3), N2O, NO, N2, and a glassy solid.
TL;DR: In this article, the Freundlich isotherm was used to predict the removal of the two viruses from distilled water solutions, and the results indicated that virus removals in excess of 98% and 92% may be expected from precipitation processes using aluminum or calcium, respectively.
Abstract: Phosphate removal from aqueous solutions by precipitation with calcium and aluminum results in large poliovirus Type I and bacteriophage T2 removals. Tests conducted in distilled water-phosphate solutions and filtered domestic wastewater effluent are described. The Freundlich isotherm is used to predict the removal of the two viruses from distilled water solutions. The pH during precipitation affects poliovirus removals. The mechanism of removal is believed to be mostly by chemical adsorption with some physical sorption occurring simultaneously. This is concluded from the inability to recover all viruses from the sludge. The sludge represents a potential health hazard and must be carefully handled. Virus removals are greater in distilled water-phosphate solutions than in wastewater treatment plant effluent. Results are extended to full scale treatment plants indicating that virus removals in excess of 98% and 92% may be expected from precipitation processes using aluminum or calcium, respectively.
TL;DR: In this paper, the authors present a methodological inquiry into the analysis of logos in the context of logos analysis, and propose a methodological approach to analyze logos in terms of semantics and semantics.
Abstract: (1970). On analysis of logos: A methodological inquiry. Quarterly Journal of Speech: Vol. 56, No. 1, pp. 22-32.
TL;DR: Analysis of the effects of cholest-4-en-3-one upon sterol synthesis in backcross offspring of the mating LAF1/J×C57L/J did not permit precise estimation of the number of genes that determine the difference in response to the dietary steroid but did suggest that the number may be relatively small.
Abstract: Hereditary factors in inbred mouse strains affected the rate of sterol synthesis from acetate and the level of hydroxymethylglutaryl coenzyme A reductase in liver in two ways. During the forenoon, rates of sterol synthesis and levels of HMG-CoA reductase activity were two- to five-fold higher in C57L/J and DBA/2J mice than in mice of strains A/HeJ or SWR/J. Due to an apparent difference in the circadian cycle of the two strains, these differences between C57BL/6J and A/HeJ strains were not as great at 4:30 pm, and in some cases the relative order of the values was reversed at this time. Low doses of dietary cholest-4-en-3-one inhibited sterol synthesis and HMG-CoA reductase in livers of all strains tested, whereas high doses or prolonged feeding of the steroid caused a relatively rapid elevation of both sterol synthesis and enzyme activity to above normal levels in several mouse strains including C57L/J. Sterol synthesis and enzyme activity in strain A/HeJ mice were depressed by dietary cholest-4-en-3-one under all conditions tested except when the steroid was fed at a low level for a prolonged period. LAF1 offspring of the cross C57L/J×A/HeJ responded to dietary cholest-4-en-3-one as did the A/HeJ parental strain. Analysis of the effects of cholest-4-en-3-one upon sterol synthesis in backcross offspring of the mating LAF1/J×C57L/J did not permit precise estimation of the number of genes that determine the difference in response to the dietary steroid but did suggest that the number may be relatively small.
TL;DR: In this article, the transformed state equation is used to determine switching times for n th-order optimal control problems, provided that the control is bang-bang with a maximum of n - 1 switches.
Abstract: The transformed state equation is used to determine switching times for n th-order optimal control problems, provided that the control is bang-bang with a maximum of n - 1 switches.
01 Jan 1970
TL;DR: In this paper, it is assumed that the structures for these mixtures are similar to the cholesteric structure and that the dielectric constant of p-methoxybenzylidene-p-cyanoaniline is greatest in a direction parallel to the long axes of the molecules.
Abstract: This work involves nematic materials mixed with small amounts of cholesteryl acetate. It is assumed that the structures for these mixtures are similar to the cholesteric structure. The dielectric constant of p-methoxybenzylidene-p-cyanoaniline is greatest in a direction parallel to the long axes of the molecules; therefore, the structure for mixtures of this material with a cholesteric material can be changed to a nematic structure by applying external electric fields. NMR techniques and measurements of the dielectric loss at a microwave frequency are used to obtain information about the cholesteric-nematic phase transition as the external electric field and the concentration of cholesteryl acetate are varied. Although mixtures of p-[n-(p-methoxybenzylidene)-amino]-phenyl acetate and cholesteryl acetate cannot be changed to a nematic phase by employing electric fields because of the negative dielectric anisotropy, an ordering can be obtained with the screw axis of the helix parallel to a 300 kHz electric field.