Showing papers in "Canadian journal of research in 1948"
TL;DR: The Cobb scale and the modified Cobb (U.S.D.A.) scale were devised for estimating, by means of diagrams, the proportion of the area of a leaf or stem occupied by rust pustules, are presented, providing a basis for more objective and accurate determinations.
Abstract: The Cobb scale and the modified Cobb (U.S.D.A.) scale were devised for estimating, by means of diagrams, the proportion of the area of a leaf or stem occupied by rust pustules. Existing diagrams il...
1,446 citations
TL;DR: A numerical key for the identification of cultures of 126 species of wood-rotting fungi, with accompanying descriptions of the cultural characters of each species, is presented.
Abstract: A numerical key for the identification of cultures of 126 species of wood-rotting fungi, with accompanying descriptions of the cultural characters of each species, is presented. The list of species...
258 citations
TL;DR: By the staining of soil with the fluorescent dye acridinorange and examination of the stained soil under the fluorescence microscope, it is possible to observe directly the living bacteria of soil in their autochthonic condition.
Abstract: By the staining of soil with the fluorescent dye acridinorange and examination of the stained soil under the fluorescence microscope, it is possible to observe directly the living bacteria of soil ...
116 citations
TL;DR: In this paper, a critical review of the "drop plate" method of determining the number of viable bacteria in fluids, together with a description of an experimental comparison of the drop plate with other methods, is presented.
Abstract: This paper is a critical review of the "drop plate" method of determining the number of viable bacteria in fluids, together with a description of an experimental comparison of the "drop plate" with...
79 citations
TL;DR: The thermal decompositions of cellobiose, maltose, dextrose, and potato starch have been studied over a temperature range, by following the production of volatile products.
Abstract: The thermal decompositions of cellobiose, maltose, dextrose, and potato starch have been studied over a temperature range, by following the production of volatile products. Carbon dioxide, carbon m...
66 citations
TL;DR: The influence of high concentrations of Mg and SO4 ions in the presence of varying concentrations of iron with ammonium succinate as the source of nitrogen on the formation of both fluorescin and pyocyanin has been determined.
Abstract: An investigation of the salt requirements for fluorescin production has been carried out, and the mineral balance for maximum fluorescin production determined. Employing ammonium succinate as a source of nitrogen, the ions PO4, Mg, SO4, and Fe have been found essential to the formation of the pigment. Optimum production of fluorescin resulted when 0.01% magnesium chloride, 0.06% dipotassium hydrogen phosphate, 0.005%, potassium sulphate, and 0.000005% (0.05 p.p.m.) ferric chloride were used.The influence of high concentrations of Mg and SO4 ions in the presence of varying concentrations of iron with ammonium succinate as the source of nitrogen on the formation of both fluorescin and pyocyanin has been determined.Fluorescin production has been demonstrated to depend primarily upon the concentration of sulphate, iron, and magnesium in the medium. The concentration of iron required has been shown to be of paramount importance. Increasing the amounts of either SO4 or Mg did not bring about the pronounced stim...
52 citations
TL;DR: Details are given of a method in which polyvinyl alcohol is used to maintain dispersion of the dye lake and colorimetric estimation of magnesium in plasma or serum by means of Titan Yellow.
Abstract: The colorimetric estimation of magnesium in plasma or serum by means of Titan Yellow requires an agent to stabilize the colored dye complex formed between magnesium hydroxide and Titan Yellow. Deta...
50 citations
TL;DR: The structure of the proventriculus in 115 species of orthopteroid insects (eight orders) is investigated and it is found that the largest group, the Blattodea, and Isoptera, have a conical Proventriculus, with 6 or 12 longitudinal teeth.
Abstract: The structure of the proventriculus in 115 species of orthopteroid insects (eight orders) is investigated.The Blattodea, Mantodea, and Isoptera have a conical proventriculus, with 6 or 12 longitudi...
48 citations
TL;DR: By employing a medium containing the required salt balance, it has been possible to obtain a fourfold increase in pyocyanin production over that obtained on other media usually employed for that purpose.
Abstract: An investigation of the salt requirements for pyocyanin production by Pseudomonas aeruginosa has been carried out, and the mineral balance for maximum pyocyanin production determined. By employing ...
48 citations
TL;DR: In this article, the ionization-energy curve in argon was found to be linear within experimental error for α-particles of energy 5 to 9 Mev. at zero ionization.
Abstract: The energies of the α-particles from weak preparations of several new radioactive substances were measured in a grid ionization chamber filled with argon. The accurately known energies of α-particles from several well known sources were used for calibration. The voltage pulses produced by electron collection from the tracks were amplified in a linear amplifier of high stability and converted into flat-topped pulses. An accurately known voltage was subtracted, and the small residual pulses were further amplified. The frequency distribution of pulse sizes was recorded on an electronic pulse analyzer.The final values of the energies are as follows:92U233, 4.823 ± 0.003; 89Ac225, 5.801 ± 0.010; 87Fr221, 6.298 ± 0.010;85At217, 7.023 ± 0.010; 84Po213, 8.336 ± 0.005; and 94Pu239, 5.159 ± 0.005 Mev.The ionization–energy curve in argon was found to be linear within experimental error for α-particles of energy 5 to 9 Mev. Extrapolation of this line determines an intercept of 85 kev. at zero ionization.
46 citations
TL;DR: The complication of a tomato breeding project by the occurrence of a spontaneous and destructive necrosis, chiefly of the foliage, in lines carrying immunity from Cladosporium fulvum Cooke physiologic races 1 to 4, is described.
Abstract: The complication of a tomato breeding project by the occurrence, in lines carrying immunity from Cladosporium fulvum Cooke physiologic races 1 to 4, of a spontaneous and destructive necrosis, chiefly of the foliage, has been described.The autogenous nature of this necrosis has been established thoroughly and the simple Mendelian nature of its inheritance determined. Immune plants, possessing the factor , are potentially necrotic if they are homozygous with respect to the factor ne, found in Lycopersicon esculentum Mill., but remain non-necrotic if homozygous or heterozygous with respect to its dominant allele, Ne, found in L. pimpinellifolium (Jusl.) Mill. Plants susceptible to C. fulvum are invariably non-necrotic.The visible expression of the gene combination , ne has been shown to vary widely according to the environmental conditions, seasonal variations in the severity of necrosis being particularly striking.The factor ne has been located on Chromosome I by three-point experiments.Necrosis appeared in...
TL;DR: In this paper, the aldehyde of the Bucherer modification of the Strecker synthesis for α-amino acids yields 5-δ-hydroxybutylhydantoin which is hydrolyzed into D,L-α-AMino-e.g., Lysine, readily isolated as the dipicrate.
Abstract: δ-Hydroxyvaleraldehyde, obtained by acid hydrolysis of dihydropyran, is a convenient starting material for the synthesis of D,L-lysine. Application to the aldehyde of the Bucherer modification of the Strecker synthesis for α-amino acids yields 5-δ-hydroxybutylhydantoin which is hydrolyzed into D,L-α-amino-e-hydroxycaproic acid. D,L-Lysine is obtained from 5-δ-hydroxybutylhydantoin by bromination with hydrobromic acid into 5-δ-bromobutylhydantoin, amination of the bromo compound with ammonia, and hydrolysis of the hydantoin ring into D,L-lysine, readily isolated as the dipicrate.
TL;DR: The substance was identified as 7-hydroxy-6-methoxy 1:2 benzopyrone (scopoletin), previously isolated by Best from tobacco plants, infected with tomato spotted wilt virus.
Abstract: A method has been described for the isolation of a crystalline fluorescent compound that occurs in Green Mountain potato tubers during the first year of infection with leaf roll virus. The substanc...
TL;DR: Winter crown rot or snow mold of alfalfa, clovers, and grasses, caused by an unidentified low-temperature basidiomycete, is widespread and often of major importance in the central and northern areas of Alberta and Saskatchewan.
Abstract: Winter crown rot or snow mold of alfalfa, clovers, and grasses, caused by an unidentified low-temperature basidiomycete, is widespread and often of major importance in the central and northern areas of Alberta and Saskatchewan. For example, during a six year period an average of 62% of the alfalfa stands examined in west-central Alberta were affected, and the average estimated damage was 10%. Severe damage also occurs in alsike and white Dutch clover, and in timothy, red top, and creeping red fescue. The disease is less prevalent in red clover, Kentucky bluegrass, and meadow fescue, and seldom occurs in brome grass, crested wheat grass, and slender wheat grass. Iris and other garden perennials, as well as dandelion, quack grass, and various wild plants are also damaged.The pathogen attacks the dormant plants beneath the snow during the first thaw in the late winter or early spring. The plants are killed or weakened in irregular patches as the result of rotting of the crown buds and tissues. These symptoms...
TL;DR: The anatomy of the adult of Monodontomerus dentipes Boh.
Abstract: The anatomy of the adult of Monodontomerus dentipes Boh, a chalcid parasite of sawfly cocoons in Europe and America, is described An attempt is made to homologize the structures of this highly modified insect with those known in more generalized insects, in the hope of clarifying some questions of chalcid morphology which has been generally neglected by entomologists The nomenclature employed is of a kind generally acceptable to students of morphology, an effort being made to eliminate the use of terms specific to a limited group of insects The anatomy of Monodontomerus is not widely different from that of phytophagous chalcids described by other authors
TL;DR: In this article, the authors describe the appropriate statistical treatment for qualitatively classified clinical and laboratory data in terms of tests of significance in binomial and multi-scale models. But they do not discuss the statistical treatment of clinical data.
Abstract: This article is designed to help investigators in applying to qualitatively classified clinical and laboratory data the appropriate statistical treatment—tests of significance in binomial and multi...
TL;DR: Evidence is presented that female mosquitoes feed on the nectar of flowers and are efficient pollinators of northern orchids, and observations on the relationships of these insects to other organisms are recorded.
Abstract: The occurrence is recorded at Churchill, Manitoba, of 5 genera and 11 species of Cuhcidae, 2 genera and 12 species of Simuliidae (3 and possibly 4 of which may be new to science), and 2 genera and ...
TL;DR: In this article, the modified Kozeny equations for the measurement of the specific surface of fine powders by gas-permeability methods have been compared and the physical significance of the empirical constants used is discussed and preference is indicated.
Abstract: The several modified Kozeny equations for the measurement of the specific surface of fine powders by gas-permeability methods have been compared. The equations all give very similar surface area values for a set of experimental data. The physical significance of the empirical constants used is discussed and preference is indicated.
TL;DR: In this paper, the fluorescence yields of the L levels have been computed separately on the basis of radiation widths obtained from the work of Massey and Burhop, the widths of Auger transitions of the Coster-Kronig type measured by Cooper, and existing information on the width of the l levels.
Abstract: The fluorescence yields of the L levels have been computed separately on the basis of radiation widths obtained from the work of Massey and Burhop, the widths of Auger transitions of the Coster–Kronig type measured by Cooper, and existing information on the widths of the L levels. In the case of fluorescence excitation, the total fluorescence yield calculated in this way is in general agreement with measurements of Lay. In the case of excitation by internal conversion of γ-radiation in the L levels, it is shown that the total fluorescence yield for elements in the vicinity of tantalum is appreciably less than the yield measured by Lay for fluorescence excitation, but that for the heavier elements near uranium, the yields should be comparable.
TL;DR: In this paper, it was shown that it is impossible to obtain ignition in a gaseous combustible mixture by any method of heating if it remains truly homogeneous while the temperature is raised.
Abstract: It should not be possible, according to the nuclear theory of ignition, stated in Part IV, to obtain ignition in the body of a gaseous combustible mixture by any method of heating if it remain truly homogeneous while the temperature is raised. Such mixtures cease to be homogeneous when heated by sudden compression to the temperatures required for ignition because of the formation of finely divided carbon by pyrolysis of lubricating oil or of hydrocarbon vapor. The finely divided carbon provides nuclear centers of ignition in the gaseous mixture. Ignition due to finely divided carbon produced by pyrolysis of the lubricant is demonstrated by experiments with hydrogen as the fuel for a C.F.R. engine. The usual pre-ignition and severe knocking were obtained when the engine in normal condition was run on hydrogen, and it was impossible, as previously found by others, to use any but weak mixtures even at low compression ratios. When however the combustion space was decarbonized and thereafter maintained reasona...
TL;DR: Two new species are described, C. erectum and C. reflexum, making a total of eight recognized species in this group of Chaetomium species, including two new species with dichotomously branched hairs.
Abstract: The large number of isolates of Chaetomium species obtained from agricultural seeds has made possible the critical study of some sections of the genus. In this paper the species with dichotomously ...
TL;DR: In this article, the authors performed viscosity and osmotic pressure measurements on dilute benzene solutions of aluminum dicaprylate, dilaurate, dimyristate, dipalmitate, distearate, and monostearate and concluded that these soaps are polymers of high molecular weight formed by weak intermolecular links.
Abstract: Viscosity and osmotic pressure measurements were carried out on dilute benzene solutions of aluminum dicaprylate, dilaurate, dimyristate, dipalmitate, distearate, and monostearate. From the results it is concluded that these soaps are polymers of high molecular weight formed by weak intermolecular links which are assumed to be hydrogen bonds. Lowering of the molecular weight by dissociation of these bonds is responsible for decreases in solution viscosities. Variations of the molecular weights obtained (60,000 to 900,000) are due, in the main, to the effect of concentration and aging on the extent of this dissociation.
TL;DR: In this paper, a whole wheat mash fermented by Aerobacillus polymyxa was stripped of ethanol, screened, and concentrated, and the resulting syrup was passed through a steam stripping column and the levo-2,3-butanediol...
Abstract: Whole wheat mash fermented by Aerobacillus polymyxa was stripped of ethanol, screened, and concentrated. The resulting syrup was passed through a steam stripping column, and the levo-2,3-butanediol...
TL;DR: The general toxicity of 127 synthetic organic compounds was tested against larvae of Musca domestica, Tribolium confusum, and Ephestia kuehniella, and adults of Sitophilus granarius, and four chlorinated aliphatic hydrocarbons showed a high toxicity related to their powerful fumigant action.
Abstract: The general toxicity of 127 synthetic organic compounds was tested against larvae of Musca domestica, Tribolium confusum, and Ephestia kuehniella, and adults of Sitophilus granarius. The compounds were mixed in the insects' food in graded concentrations, and their toxicity was assessed by determination of the median lethal concentrations (LC50) for each of the four species. The most highly toxic compounds were gammexane (the gamma isomer of hexachlorocyclohexane) and chlordane (obtained by distillation of technical chlordane). The toxicity of DDT was on the average one-half of that of the first two compounds, and it was superior to any of the 12 analogues tested. Four chlorinated aliphatic hydrocarbons, namely hexachloropropene, hexachlorobutadiene, and the symm-and asymm-heptachloropropanes, showed a high toxicity related to their powerful fumigant action. A high level of toxicity was shown by benzyl thiocyanate and its chlorinated derivatives. The nitro compounds dinitro-o-cresol, nitrostyrene, dinitrod...
TL;DR: In this paper, an analysis of the products of sodium-catalyzed polymerization of butadiene and isoprene in the presence of toluene suggests that initiation of polymerization takes place by the formation of a disodium addend rather than a free radical.
Abstract: An analysis of the products of sodium-catalyzed polymerization of butadiene and isoprene in the presence of toluene suggests that initiation of polymerization takes place by the formation of a disodium addend rather than a free radical. The diaddend reacts with toluene to yield butene-2 and sodium benzyl. Since all of the low molecular weight polymers analyzed were shown to conform to the general formula C6H5CH2(monomer)nH, sodium benzyl is considered to be the chief chain initiator. Chain termination took place by reaction with toluene to regenerate the chain carrier, sodium benzyl. The nature of the acids separated on carbonation of a polymerizing system supports this conclusion.
TL;DR: The modified Kozeny equation has been found to be satisfactory for the measurement of the specific surfaces of carbon blacks having average particle diameters ranging from 0.01 to 0.1 μ to within ±10%.
Abstract: The modified Kozeny equation has been found to be satisfactory for the measurement of the specific surfaces of carbon blacks having average particle diameters ranging from 0.01 to 0.1 μ to within ±10%. Comparative data were obtained from electron microscope counting and from low temperature nitrogen adsorption isotherms. The three methods examined gave results that were in satisfactory agreement, except when the carbon black was porous, and then the adsorption value was extremely large.
TL;DR: The pure explosive is a stable low-melting solid with power and detonation rate higher than those of nitroglycerin and recommends it as a replacement for the latter substance in explosive compositions.
Abstract: It has been found possible to convert diethanolamine to β,β-dinitroxydiethylnitramine by inclusion of hydrogen chloride or one of its salts as catalyst. The structure of this powerful explosive has been demonstrated by an alternative synthesis involving nitrosation of dinitroxydiethylammonium nitrate, followed by subsequent oxidation of dinitroxydiethylnitrosamine to the corresponding nitramine. The nitrosamine, which is unstable in boiling water, is evidently an impurity in the crude nitramine. It may be removed from the stable nitramine by blowing the suspension of molten crude product with steam. The pure explosive is a stable low-melting solid with power and detonation rate higher than those of nitroglycerin. Its insensitiveness to impact as compared with nitroglycerin recommends it as a replacement for the latter substance in explosive compositions.
TL;DR: Radioautographs indicate that at five weeks' growth the distribution of phosphorus in a wheat plant is fairly uniform whereas that ofstrontium is very uneven, practically all the strontium being concentrated in the first two leaves.
Abstract: The lethal dose of P32 and Sr90 for wheat, barley, and sunflower seeds is approximately 1.4 microcuries per seed (0.05 rd.). Radioautographs indicate that at five weeks' growth the distribution of phosphorus in a wheat plant is fairly uniform whereas that of strontium is very uneven, practically all the strontium being concentrated in the first two leaves.
TL;DR: It appeared that the body defences, in resistant animals, acted against the parasites, and resistance was apparent from the amount of congestion in the lungs and the number and size of the larvae recovered from the lungs.
Abstract: Clinical symptoms of Ascaris infection were produced in guinea pigs by feeding several thousand eggs. Such infections caused a temporary loss in weight and severe congestion of the lungs but no elevation in temperature was observed. An eosinophilia was associated with infection and it reached higher levels following repeated infections. Injections of antigen caused a temporary rise in the number of eosinophiles. Guinea pigs developed a resistance as a result of infection. Some resistance was retained for at least 15 weeks following infection. A slight passive resistance resulted from injections of large quantities of serum from resistant animals and from injections of a liver extract prepared from resistant animals. The resistance was apparent from the amount of congestion in the lungs and the number and size of the larvae recovered from the lungs. The eosinophiles per se were not responsible for the resistance observed. It appeared that the body defences, in resistant animals, acted against the parasites...
TL;DR: For example, Lycopodium cernuum L., has yielded a new alkaloid, cernuine (L32), C16N26ON2, nicotine, and an uncharacterized base (L33) as mentioned in this paper.
Abstract: Lycopodium cernuum L., has yielded a new alkaloid, cernuine (L32), C16N26ON2, nicotine, and an uncharacterized base (L33). Lycopodine could not be isolated.