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Showing papers by "Newcastle University published in 1969"


Journal ArticleDOI
TL;DR: In this article, the system of equations for the magneto-acoustic wave propagating along a critical direction is reduced to a simple dispersive equation similar to the Korteweg-de Vries equation except that the third order derivative (the dispersion term) is replaced by the fifth order one.
Abstract: The hydromagnetic waves with small but finite amplitude in a cold collision-free plasma are investigated by using a nonlinear perturbation method. In the lowest order of perturbation, we can show that the system of equations for the magneto-acoustic wave propagating along a `critical' direction is reduced to a simple dispersive equation similar to the Korteweg-de Vries equation except that the third order derivative (the dispersion term) is replaced by the fifth order one. An extension of the problem to more general dispersive system is also made. On the other hand, the system of equations for the Alfven wave is reduced to a modified Korteweg-de Vries equation in the sense that the non-linear term f ∂ f /∂ξ in the Korteweg-de Vries equation is replaced by f 2 ∂/∂ξ. In the case of steady propagation this equation can be integrated to give a solution in closed form, which exhibits a solitary wave. Two kinds of solitary wave (both compressive and rarefied) are found to be possible.

363 citations


Journal ArticleDOI
TL;DR: In this article, the transient and steady state responses of electrodes under conditions where two-dimensional nucleation is rate determining are considered, and the experimental results show that the response of the electrodes to rate determination is stable.
Abstract: The transient and steady‐state responses of electrodes under conditions where two‐dimensional nucleation is rate determining are considered.

139 citations


Journal ArticleDOI
TL;DR: In seven experiments sheep were given diets ranging from all-hay to all-barley, and also a diet comprising one part hay to two parts flaked maize, and some values for a fraction designated non-glucose reducing polymer for cellulose and for gross energy were obtained.
Abstract: 1. In seven experiments sheep were given diets ranging from all-hay to all-barley, and also a diet comprising one part hay to two parts flaked maize. Each sheep was equipped with a cannula into the rumen and a re-entrant cannula in the proximal duodenum; six of the ten also had a re-entrant cannula in the terminal ileum. Paper impregnated with chromic oxide (Cr2O3) was given twice daily by rumen fistula. 2. Amounts of α-linked glucose polymer entering and leaving the small intestine and excreted in the faeces were measured. Some values for a fraction designated non-glucose reducing polymer for cellulose and for gross energy were also obtained. The amounts passing the proximal duodenum and the terminal ileum were adjusted to give 100% recovery of Cr2O3 and the values were used to measure the extent of digestion in various parts of the alimentary tract. 3. When rolled or whole barley was given alone or was the major feed constituent the amount of α-linked glucose polymer entering the small intestine was 6.0±0.76% of that ingested (range 2.6–8.1%). The value was significantly lower than that found for the diet of hay and flaked maize (10.4±1.3%, range 8.0–13.6 %).The α-linked glucose polymer which entered the small intestine was almost completely digested there. 4. The digestibility of the non-glucose reducing polymer, which included much of the hemicelluloses present, ranged from 51 to 73% and almost all the digestible fraction (93–97%) was digested before the small intestine when hay or predominantly hay diets were given. On high-cereal diets only 71–85% of the digested fraction disappeared before the small intestine and appreciable amounts were digested in the large intestine. 5. On the all-hay diet 91% of the digestible cellulose and 67% of the digestible energy were lost before the small intestine, 0 and 21% in the small intestine and 9 and 12% in the large intestine. 6. Mean digestibility coefficients determined in sheep fed solely on either whole or rolled barley were: for dry matter 88.1 and 87.9%, for nitrogen 83.5 and 82.1%, for crude fibre 53.7 and 56.6% and for gross energy 87.7 and 88.0%.

138 citations


Journal ArticleDOI
TL;DR: In this article, plant roots were grown in a modified triaxial apparatus and were subjected to a range of confining hydrostatic stresses, and it was found that confining pressures around 3 lbf/in2 were reasonably well tolerated by the roots, but as the pressure was increased beyond this value root elongation was rapidly attenuated until at pressures beyond 9 lbf /in2 root growth was almost completely arrested.

136 citations


Journal ArticleDOI
TL;DR: Analyses were made of the fatty-acid composition of Candida utilis NCYC 321 grown in a chemostat at a dilution rate (equal to growth rate) and at temperatures in the range of 30 to 15 C and dissolved oxygen tensions between 75 and <1 mm of Hg.
Abstract: Analyses were made of the fatty-acid composition of Candida utilis NCYC 321 grown in a chemostat at a dilution rate (equal to growth rate) of 0.1 hr(-1) and at temperatures in the range of 30 to 15 C and dissolved oxygen tensions between 75 and <1 mm of Hg. Cells grown under glucose limitation or NH(4) (+) limitation contained mainly C(16:0), C(16:1), C(18:0), C(18:1), C(18:2), and C(18:3) acids as detected by gas-liquid chromatography of methyl esters of the acids from lipids extracted with chloroform-methanol. The relative proportions of these acids varied with the growth temperature and the dissolved-oxygen tension in the culture. A decrease in growth temperature from 30 to 20 C led to an increased synthesis of unsaturated acids in cells grown under either limitation at a fixed-oxygen tension in the range of 75 to 5 mm of Hg. In cultures with a dissolved-oxygen tension of 1 and <1 mm of Hg, a further decrease in temperature to 15 C caused an increased synthesis of unsaturated fatty acids. A decrease in dissolved-oxygen tension led to a diminished synthesis of unsaturated fatty acids in cells grown at a fixed temperature under either limitation. Cells grown at a fixed temperature under glucose limitation synthesized a greater proportion of C(16) acids at the expense of C(18) acids as the dissolved oxygen tension was decreased from 75 to <1 mm of Hg. A preferential synthesis of C(16) acids also occurred as the growth temperature was decreased from 30 to 15 C in cells grown under glucose limitation at a fixed-oxygen tension. The same effect was observed in cells grown under NH(4) (+) limitation when the temperature was lowered from 30 to 20 C; but when the temperature was decreased further to 15 C, the cells synthesized a slightly greater proportion of C(18) acids. Synthesis of a large proportion of C(16) acids was accompanied by an excretion of pyruvate, and occasionally traces of 2-ketoglutarate, and an increased intracellular accumulation of certain amino acids.

134 citations


Book
01 Jan 1969
TL;DR: This manual contains answers to the even numbered problems listed at the end of the chapters in the 5th edition of "Mathematics for Engineers and Scientists".
Abstract: This manual contains answers to the even numbered problems listed at the end of the chapters in the 5th edition of "Mathematics for Engineers and Scientists". For those problems requiring a little thought, outline solutions are provided as well as the final answer.

106 citations



Journal ArticleDOI
TL;DR: It is concluded that a high proportion of plaque fluorine is contained within the bacteria, suggesting that the stored fluorine was active as an inhibitor.

88 citations


Journal ArticleDOI
01 Mar 1969
TL;DR: Siewert, K. L. & Otterby, D. E. (1968).
Abstract: Siewert, K. L. & Otterby, D. E. (1968). J . Dairy Sti. 51, 1305. Smith, K. H. (1964). J. Physiol., Lond. 172, 305. Stein, J. F., Knodt, C . B. & Ross, E. B. (1954). J. Dniry Sci. 37, 373. Vclu, J. G., Kendall, K. A. & Gardnei, K. E. (1960). J . Dairy Sci. 43, 546. Walker, D. NI. (1959). J. ugrir. Sci., Camb. 53, 374. Xenoulis, P. K., Jacobson, N. L., Young, J. W., McGilliard, A. L). & Allen, R. S. (1967). J. Anirn. 23. (In the Press.)

81 citations


Journal ArticleDOI
TL;DR: Candida utilis NCYC 321 was grown in steady-state culture in a chemostat under glucose limitation or NH(4) (+) limitation at temperatures of 30, 25, 20, and 15 C and at dilution rates (equal to growth rates) in the range of 0.35 to 0.05 hr(-1).
Abstract: Candida utilis NCYC 321 was grown in steady-state culture in a chemostat under glucose limitation or NH(4) (+) limitation at temperatures of 30, 25, 20, and 15 C and at dilution rates (equal to growth rates) in the range of 0.35 to 0.05 hr(-1). Deoxyribonucleic acid contents of cells grown under the various conditions remained approximately constant, but the contents of several other cell components varied. Over the range of 30 to 15 C, the greatest differences were in the ribonucleic acid (RNA) and protein contents of cells grown under NH(4) (+) limitation, which increased as the temperature was decreased. The contents of other components, particularly adenosine triphosphate in cells grown under glucose limitation, varied more when the cells were grown at different rates at a fixed temperature. Cells grown at a fixed rate under NH(4) (+) limitation increased in volume as the temperature was decreased below 30 C. The increase in volume was closely correlated with increases in the proportions of RNA and protein in the dry weight of cells. Cells grown under glucose limitation showed much smaller increases in volume; these increases were poorly correlated with the increased RNA content and hardly at all with the increased protein content. Increases in volume with a decrease in growth temperature from 30 to 20 C were also demonstrated in cells grown under phosphate limitation and to a much smaller extent in cells grown under glycerol limitation. The increased RNA synthesized at low temperatures by cells grown under NH(4) (+) limitation was found almost exclusively in the 40,000 x g supernatant fluid, but only about 40% of it sedimented at 100,000 x g. Cells grown at a fixed rate under NH(4) (+) limitation synthesized less total carbohydrate when the temperature was decreased from 30 to 15 C. This decrease was mainly in the trichloroacetic acid-soluble fraction (probably trehalose) and in the intracellular hot alkali-soluble glucan (probably glycogen). Cells grown at a fixed rate under glucose limitation showed a small increase in carbohydrate content as the temperature was decreased from 30 to 15 C.

79 citations


Journal ArticleDOI
TL;DR: A quantitative analysis indicates that the spectral changes are due to replacement by water of one molecule of co-ordinated dimethyl sulphoxide per ferrihaem aggregate, and do not involve a two-molecule replacement as has been suggested for the alkaline pyridine-water system.
Abstract: 1. Conductivity and u.v. and visible spectroscopic techniques were used to investigate the solution structure of the prosthetic group of the ferric haemoproteins (ferrihaem) in dimethyl sulphoxide, NN-dimethylacetamide, NN-dimethylformamide and sulpholane, and certain of their aqueous mixtures. 2. In neutral or acid dimethyl sulphoxide, chlorohaemin is monomeric and completely dissociated into Cl(-)ion and a ferrihaem species with dimethyl sulphoxide molecules in the fifth and sixth co-ordination positions on iron. 3. In neutral NN-dimethylacetamide and NN-dimethylformamide chlorohaemin is monomeric but is largely undissociated, giving different spectra from that of chlorohaemin in dimethyl sulphoxide. On acidification, dissociation occurs and the dimethyl sulphoxide type of spectrum results. 4. Studies in a fourth solvent, sulpholane, indicate that solvent co-ordinating power (ligand strength) rather than bulk dielectric constant is responsible for dissociation of chlorohaemin. 5. In neutral dimethyl sulphoxide-water mixtures chlorohaemin remains monomeric and completely dissociated, and spectra are independent of mixture composition, except at high water concentrations, when precipitation occurs. In alkaline dimethyl sulphoxide-water mixtures, where the complete solvent mixture range is accessible, ferrihaem is polymeric (probably dimeric) and spectra are dependent on solvent composition. A quantitative analysis indicates that the spectral changes are due to replacement by water of one molecule of co-ordinated dimethyl sulphoxide per ferrihaem aggregate, and do not involve a two-molecule replacement as has been suggested for the alkaline pyridine-water system.

Journal ArticleDOI
TL;DR: In this article, the cross sections for the single ionization of He+ ions by electrons with energies ranging from threshold (544 ev) to 10 kev have been made of cross sections.
Abstract: Absolute measurements have been made of cross sections for the single ionization of He+ ions by electrons with energies which ranged from threshold (544 ev) to 10 kev. The results are in good agreement with those of an earlier experiment by Dolder et al. (1961) which was confined to energies below 1 kev. Cross sections for the single ionization of Li+ have also been measured for electron energies between 3 and 25 kev. Comparison of these results with calculations (performed elsewhere) based on the Born and Bethe approximations shows that, for both ions, the former approximation gives results in excellent agreement with the experiments when the electron energies exceed twenty times threshold, whilst the Bethe approximation is only valid for energies greater than about 50 times threshold.

Journal ArticleDOI
TL;DR: In this article, a continuum theory was proposed for liquid crystals of the cholesteric type, where the liquid crystal is regarded as an incompressible liquid with a preferred direction at each point described by a unit vector.
Abstract: This paper discusses a continuum theory which has recently been proposed for liquid crystals of the cholesteric type. As in earlier continuum theories, the liquid crystal is regarded as an incompressible liquid with a preferred direction at each point, described by a unit vector. Solutions of the equations are investigated for shear flow between two flat plates, one at rest, and the second moving parallel to the first with a constant velocity. It is found that the theory predicts non-Newtonian behaviour, and that secondary flow and temperature variations occur. The predictions are compared with available experimental data, and one finds agreement in that a uniform apparent viscosity is predicted at large shear rates.



Journal ArticleDOI
19 Apr 1969-Nature
TL;DR: Transparent shrimps have been used to study bubble formation under decompression and their role in research into bubble formation is still under investigation.
Abstract: Transparent shrimps have been used to study bubble formation under decompression.

Journal ArticleDOI
15 Mar 1969-Nature
TL;DR: Using the Tanzania earthquakes of 1964, May 7, as a master event, epicentres have been relocated for Africa, south of 5° S. The relocations suggest that the East African rift system may extend considerably farther south than was previously thought.
Abstract: Using the Tanzania earthquakes of 1964, May 7, as a master event, epicentres have been relocated for Africa, south of 5° S. The relocations suggest that the East African rift system may extend considerably farther south than was previously thought.

Journal ArticleDOI
TL;DR: The T1 tiller occurred most frequently in the newest variety, Deba Abed, and least in the oldest one, Spratt Archer, while Survival rates of the shoots were highest in M, followed by T2, T1 and T3.
Abstract: Two field experiments have been conducted to investigate the pattern of tillering, ear emergence and survival of the component tillers of three barley varieties, representing old and new varieties. The varieties were grown under contrasting nitrogen fertilizer levels and plant spacings. The results reported are for the variety means and variety x nitrogen and variety x spacing interactions. After the main stem (M) the most frequently occurring tiller was the tiller appearing in the axil of the first true leaf (T2), followed by the coleoptile node tiller (T1) and the tiller in the axil of the second true leaf (T3). The T1 tiller occurred most frequently in the newest variety, Deba Abed, and least in the oldest one, Spratt Archer. Survival rates of the shoots were highest in M, followed by T2, T1 and T3. Higher-order tillers occurred relatively infrequently and had low survival rates. M contributed the largest percentage of the grain yield, followed by T2, T1 and T3. The 13% grain yield advantage of Deba Abed over Spratt Archer was mainly accounted for by the difference in production by the T1 tiller. The results are discussed in. relation to the only other known paper on component tillers in barley.

Journal ArticleDOI
TL;DR: This article found that liking is a form of "commitment" which leads to the need for cognitive dissonance, and that the first factor in the principal components analysis of the judgements of the dress was a factor which predicted ranked fashionableness rather than simply liking.
Abstract: It is argued that many of the suggested functions of clothing can be seen as special cases of the idea that it acts as a means of communication. Fashion changes may thus often be explainable as attempts to communicate superiority in some respects by the self-defeating method of changing garment styles, for if they communicate successfully they will be imitated by many people and thus the message of the clothing will be changed. This will require a fashion change, again, to continue to communicate the same message. The experimental part of the paper reports an investigation in which six pictures of current outfits were judged by 50 15- or 16-year-old girls. The judgements were of two kinds: by a type of semantic differential scale, on which ideal self was also judged, and by a questionnaire asking specific questions about various attributes of the persons who would be likely to wear the outfits. The results indicated that there was high consensus as to the specific attributes seen by this group as belonging to the likely wearers of each dress which was not explicable on a general evaluative basis. It was also shown very clearly that the impression created by the liked dresses was seen as much nearer the impression of the ideal-self than was the disliked ones and it was found that likers and dislikers differed, both in the actual ideal self image and in their judgements of the dresses, suggesting that liking is a form of ‘commitment’ which leads to the need for cognitive dissonance. A very important finding was that the first factor in the principal components analysis of the judgements of the dress was a factor which predicted ranked fashionableness in the group (r = 0.99) rather than simply liking. This finding could provide a measuring device for analysing the cognitive content of fashion for different groups and for studying the possible change of meaning of an outfit as it passes into and out of fashion.

Journal ArticleDOI
30 Aug 1969-Nature
TL;DR: It is not yet known whether the growth-regulating chalone is a feature common to all tissues, but essential components in this controlling mechanism have been found to be chemical messengers produced by cells which themselves form the target tissue.
Abstract: THE existence of a growth-regulating system has now been established in several tissues, but has been thoroughly investigated only in mammalian epidermis1–3 and granulocytes4. Essential components in this controlling mechanism have been found to be chemical messengers, known as chalones, produced by cells which themselves form the target tissue. As a result of chalone activity, the mitotic cycle of the cell is modified and the rate of growth of the whole tissue potentially depressed5. It is not yet known, however, whether the growth-regulating chalone is a feature common to all tissues.

Journal ArticleDOI
TL;DR: Five hydrolytic enzymes have been studied histochemically in the cells of the digestive gland of Mytilus edulis, Helix aspersa, and certain other lamellibranchs and gastropods.
Abstract: Five hydrolytic enzymes (acid phosphatase, aryl sulphatase, β-glucuronidase, N-acetyl-β-glucosaminidase, and non-specific esterase) have been studied histochemically in the cells of the digestive gland of Mytilus edulis, Helix aspersa, and certain other lamellibranchs and gastropods. All the enzymes studied have basically similar distributions. In the digestive cells, the enzymes occur in cytoplasmic granules which are believed to be primary lysosomes; in vacuoles which contain phagocytosed food material; and in vacuoles containing lipofuscin granules, which are the residues of digestive activity. In the basiphil cells of M. edulis, most of the enzymes are localized in a few cytoplasmic granules; non-specific esterase, however, is found throughout the cytoplasm. In the calcium cells of H. aspersa and the other pulmonate gastropods studied, the enzymes are either in cytoplasmic granules, or distributed diffusely throughout the cytoplasm. Acid phosphatase is also found in the calcium spherules, especially in H. aspersa. In the excretory cells of H. aspersa and the other pulmonates studied, the enzymes are found in granules in the cytoplasm, and in the lipofuscin granules which lie in the vacuoles of these cells.


Journal ArticleDOI
TL;DR: Dendraster excentricus was observed at Alki Point, Seattle, Washington, at a maximum density of 629 animals/m 2 during the summer of 1967, and forward movement (progression) is the dominant pattern of locomotion, although a reversed movement is possible.


Journal ArticleDOI
R. Binns1
TL;DR: In this article, the authors measured the space of inulin distribution in crabs and found that it represents approximately 20% of the body weight in crabs ranging in size from 20.0 to 57.2 g.
Abstract: 1. The space measured by inulin distribution, the ‘inulin volume’, has been determined, and represents approximately 20% of the body weight in crabs ranging in size from 20.0 to 57.2 g. 2. After the injection of labelled inulin into crabs, the increase in activity of the medium is equal to the fall in blood inulin in all dilutions of sea water. Clearance of inulin from the blood is due only to urine production, and therefore the molecule can be used for quantitative investigations of antennal gland function. 3. Urine production in various concentrations of sea water has been determined by measuring the clearance of inulin from the blood and the rates at which the tracer appeared in the external media. By these methods the mean rate of urine production in 100% sea water was estimated to be 4.4% body weight per day. In dilute sea water the rate of urine production increases; for example, in 50% sea water the urine flow is four times greater than in normal sea water.

Journal ArticleDOI
TL;DR: In this paper, the interaction of ions and quantized vortex lines in helium II is treated by imagining that the motion of the superfluid near a vortex line acts on an ion so as to produce a potential well.
Abstract: The interaction of ions and quantized vortex lines in helium II is treated by imagining that the motion of the superfluid near a vortex line acts on an ion so as to produce a potential well. The ion itself is looked upon as a Brownian particle immersed in a gas of quasi-particles. The capture of ions is pictured as a process of sedimentation into the well. The escape of the ions from the well is treated as a problem of the escape of a Brownian particle over a potential barrier. A solution of the Fokker-Planck equation for a two-dimensional well is given. Comparison of the theory with a variety of experiments is presented.


Journal ArticleDOI
30 Aug 1969-Nature
TL;DR: The ferric-proto-porphyrin IX complex, haemin, exhibits, in a primitive form, the catalytic properties of the haemoproteins, catalase and peroxidase, of which it is the prosthetic group, and is therefore a valuable model system.
Abstract: IRON–PORPHYRIN complexes are important components of a variety of biological catalysts. The ferric-proto-porphyrin IX complex, haemin (usually isolated as the chloro-complex, chloro-protohaemin or haemin chloride), exhibits, in a primitive form, the catalytic properties of the haemoproteins, catalase and peroxidase, of which it is the prosthetic group, and is therefore a valuable model system. Although the crystal structure of chloroproto-haemin is established1, there remains considerable uncertainty about the nature of haemin in solution. Many lines of evidence (magnetic2,3, polarographic4, ultracentrifuge5, kinetic6, spectroscopic and complexation studies6,7) suggest that haemin exists in aqueous alkaline solutions mainly in dimeric form(s). Recent studies in this laboratory of the electronic spectra of haemin solutions, both in water (private communication, T. C. Dean) and in dipolar aprotic solvents (S. B. B. and I. R. L., unpublished results), have shown that dimerization is accompanied by dramatic spectral changes in the Soret band region. Some authors consider that further aggregation6 (for example, tetra-merization) may occur to some extent, but this is less certain, and there are undoubtedly other complicating factors, particularly if the solutions are exposed to the atmosphere8.

Book ChapterDOI
01 Jan 1969
TL;DR: In this article, the history and evolution of the Red Sea are considered in the light of the continental movement of Africa and Arabia, and relevant palaeomagnetic data pertaining to the latter are summarized.
Abstract: The history and evolution of the Red Sea are considered in the light of the continental movement of Africa and Arabia. The relevant palaeomagnetic data pertaining to the latter are summarized. The Red Sea developed in phases, and it is likely that these correspond in time to phases of continental drift. The geophysical data for the Red Sea are summarized in a general resume and in more detail by considering the Red Sea in three parts, viz. the northern Red Sea (north of 25°N), the central Red Sea (17° to 25°N) and southern Red Sea (south of 17°N). Structural differences from north to south are noted. Finally, a summary is given for the evolution of the Red Sea taking into account geophysical and geological data for the whole Afro-Arabian region.

Journal ArticleDOI
TL;DR: In this article, it was shown that thin layers of platinum and ruthenium on mercury behave differently from nuclei of the same metals grown on a carbon substrate, and that the mechanism of hydrogen evolution is controlled by direct discharge of H+ in the case of platinum, while the relative current densities into edge and top of the two dimensional layers being about 100:1.