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Showing papers by "Trinity College, Dublin published in 1980"


Journal ArticleDOI
01 Mar 1980
TL;DR: The concept of a baseline is fundamental to the formation of a Biological Quality Index and Pollution Load Index, and a formula for such an index is suggested and tested at a preliminary level against published data for an English and a European estuary as discussed by the authors.
Abstract: Most estuaries receive a high heavy-metal input from industries. This is reflected in the relatively high levels found in numerous estuarine organisms and in sediments. Many indicators have been suggested for facilitating the detection of heavy-metal pollution, but the problems in using these indicators to evaluate the metal loading of estuaries are considerable. Variations in species composition, and conditions at different sites, differences in season of sampling, and age of organism, as well as different metal levels in different parts of the organism, make the interpretation of results difficult. The levels reported here, similar to those in other unpolluted estuaries, have been used to suggest a baseline concentration for heavy metals in estuaries. The concept of a baseline is fundamental to the formation of a “Biological Quality Index” and “Pollution Load Index,” and a formula for such an index is suggested and tested at a preliminary level against published data for an English and a European estuary.

2,313 citations


Journal ArticleDOI
TL;DR: In this paper, the authors simplify and extend the theory of household behavior under rationing, using duality and the concept of virtual prices, and derive Slutsky-type equations, decomposing the derivatives of the rationed demand functions into income and substitution effects.

543 citations


Journal ArticleDOI
27 Nov 1980-Nature
TL;DR: Some of the genes controlling start by isolating mutants which are altered with respect to the conditions in which start occurs are identified, including whi-2, which is involved in the mechanism whereby cells arrest in G1 in stationary phase.
Abstract: In many eukaryotes it is thought that cell proliferation is regulated at a point in G1 close to the initiation of DNA synthesis1. Hartwell2,3 and his colleagues have shown such a point in G1 phase in the budding yeast, Saccharomyces cerevisiae, defined by the cdc 28 mutation. He has termed this point ‘start’ and showed that for cells to proceed beyond start, initiate DNA synthesis and produce a bud, various conditions must be met. Two of these conditions are the presence of adequate nutrients in the medium and the attainment of a critical size. We identify here some of the genes controlling start by isolating mutants which are altered with respect to the conditions in which start occurs. Two types of mutant have been isolated. One results in bud initiation when the parent cell is only half the size at which bud initiation occurs in wild-type cells. Such mutants define a single gene, whi-1, and they are apparently analogous to the size mutants isolated by Nurse and his colleagues4–6 in Schizosaccharomyces pombe. A second type of mutation affects a second gene, whi-2, which is involved in the mechanism whereby cells arrest in G1 in stationary phase. whi-2− cells growing exponentially initiate buds at the same size as wild-type cells. In stationary phase, however, whi-2− cells, unlike wild-type cells, are predominantly budded and are smaller than wild-type cells.

209 citations


Journal ArticleDOI
TL;DR: A pollen assemblage of Pinus banksiana (jack pine), Picea (spruce), and herbs is dated between 19,100 and 12,800 14C yr B.P. at White Pond near Columbia, South Carolina as mentioned in this paper.

141 citations


Journal ArticleDOI
01 Aug 1980-Chest
TL;DR: The results suggest that residence in the two polluted areas is associated with respiratory impairment, primarily of functions of the large airways.

136 citations


Journal ArticleDOI
TL;DR: This article found evidence that readers use the episode schema in encoding the information of simple two-episode stories and that the encoding load was greater at the boundary nodes than at the remaining nodes of an episode.

113 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that self-dual solutions of Einstein's equations, with cosmological constant λ, correspond to certain complex manifolds, and this result generalizes the work of Penrose [1], who dealt with the case λ=0.
Abstract: It is shown that self-dual solutions of Einstein's equations, with cosmological constant λ, correspond to certain complex manifolds. This result generalizes the work of Penrose [1], who dealt with the case λ=0.

112 citations


Journal ArticleDOI
TL;DR: In this article, the reduced model developed in part I of this paper was used to derive a nonlinear hyperbolic equation which describes the passage of kinematic waves along the surface of a valley glacier.
Abstract: We show how the ‘reduced’ model developed in part I of this paper may be used to derive a nonlinear hyperbolic equation which describes the passage of kinematic waves along the surface of a valley glacier. Qualitative descriptions of large-scale snout movements and the formation and evolution of surface shocks are found from this approach, and earlier results of Nye (1960) are reproduced in the limit where surface disturbance amplitudes are ‘small’.

96 citations


Journal ArticleDOI
01 Sep 1980-Nature
TL;DR: The earliest record of a fossil flora containing Cooksonia type sporangia was from a mid-Ludlow (Silurian) locality in Wales as discussed by the authors, which was collected in the Devilsbit Mountain district of County Tipperary, Ireland.
Abstract: Hitherto the earliest record of a fossil flora containing Cooksonia type sporangia was from a mid-Ludlow (Silurian) locality in Wales1. The compression fossils illustrated here (Figs 1–4) come from strata assigned to the highest graptolite zone of the Wenlock Series characterized by Monograptus ludensis. They were collected (by J. F.) in the Devilsbit Mountain district of County Tipperary, Ireland. But this is not just a record of the first appearance of a genus which extends to the end of the Lower Devonian, because Cooksonia has generally been accepted as a vascular plant2. Its occurrence at the top of the Wenlock therefore seems to extend the history of vascular plants back to the middle of the Silurian and to indicate that higher plants colonized land surfaces at least 415 Myr ago.

94 citations


Journal ArticleDOI
Abstract: This paper explores the implications for international monetary economics of recent work on macroeconomic models of temporary equilibrium with rationing. A model of a small open economy is presented, which, though fully consistent in the long run with the monetary approach to the balance of payments, behaves very differently in the short run when the wage and the price of nontradeables are sticky. Among the comparative statics properties of the model are the following: a devaluation may not improve the trade balance; a wage cut may not increase employment; and technological progress has different effects, depending on the sector in which it occurs.

91 citations


Journal ArticleDOI
TL;DR: In this paper, single crystals of pure and carbon-substituted divalent hexaborides EuB6 and YbB6 have been prepared by the Al flux method.
Abstract: Single crystals of pure and carbon‐substituted divalent hexaborides EuB6 and YbB6 have been prepared by the Al flux method. Lattice parameters, density measurements, and microprobe analysis show that the single crystals are very close to stoichiometry. EuB6 is ferromagnetic (TC=12.5 K and ϑp=15 K) whileYbB6 is diamagnetic. Resistivity and Hall effect measurements carried out over a wide temperature range show that both pure hexaborides are semiconductors with a small intrinsic gap. The carbon‐substituted hexaborides RE B6−xCx (RE=Eu, Yb) have a metallic behavior due to the donation of electrons to the conduction band by carbon atoms. Metallic conduction, at low temperature, in the ’’pure’’ hexaborides is attributed to the formation of an impurity band containing more than 1018 electrons per cm3.

Journal ArticleDOI
TL;DR: Up to three different muscle nerves were dissected from each limb, post‐fixed in osmium tetroxide and embedded in Epon, and fibres in each nerve could be examined individually by electron microscopy.
Abstract: 1. One hind limb of each of four cats was either chronically de-efferentated, or chronically de-afferentated, and perfused with buffered glutaraldehyde fixative. Up to three different muscle nerves were dissected from each limb, post-fixed in osmium tetroxide and embedded in Epon. Ultrathin transverse sections were mounted on Formvar-coated single-hole specimen grids so that all the fibres in each nerve could be examined individually by electron microscopy. 2. Non-circularity was expressed as the ratio (o): [Formula: see text] The degree of non-circularity of all the afferent axons, or all the efferent axons, in each muscle nerve was determined. The proportion of fibres cut through the paranodal region, or through the Schwann cell nucleus, was as expected for group I afferent and for α and γ efferent fibres, but hardly any typical paranodal sections of group II or III afferent fibres were encountered which suggests that their paranodal arrangement differs from that of other groups. In a quantitative comparison of noncircularity in different functional groups, fibres cut through paranodes, Schwann cell nuclei or Schmidt-Lanterman clefts were rejected. 3. All the γ efferent fibres in one nerve were studied in a series of sections cut at 25 μm intervals. The degree of non-circularity was found to be relatively constant along the internode of most fibres when the values at paranodes, Schwann cell nuclei or Schmidt-Lanterman clefts were ignored. 4. The value of o varied widely from 1·0 (circular) to 0·5 or less from fibre to fibre within every functional group. However, the mean value of o was less for γ axons (0·68) than for α axons (0·78), and less for group III axons (0·79) than for axons in groups I and II (both 0·84). When the results for all the nerves were aggregated, these differences were statistically very highly significant, as was the difference in o between group I and α fibres. If values of o < 0·5 were rejected, the difference between the mean o for group III and group II was then of doubtful significance whereas that between α and γ fibres was still very highly significant. 5. The external perimeter (S) of a non-circular fibre differs from π times the diameter of a circle just enclosing the fibre (D). It is shown that S = 0·95 π D for group I and II fibres, S = 0·90 πD for α and group III fibres, and S = 0·85 πD for γ fibres. 6. The myelin period, or interperiod repeat distance, varied from 14·1 to 15·6 nm in different cats, implying radial shrinkage of the myelin sheath from 15 to 23%. The myelin period in a particular cat was the same for several nerves, and the same for fibres in different functional groups. 7. The possibility that repetitive firing of axons during fixation contributed to the varying degree of non-circularity is considered but rejected as unlikely. 8. It is deduced that about 10% radial shrinkage of the myelin sheath, but little or no osmotic shrinkage of the axon, occurred during fixation and rinsing. Further radial shrinkage of about 8% in all components of the fibre probably occurred as a result of subsequent histological processing. It is concluded that the non-circularity of all axons, and the greater non-circularity of small axons, is unlikely to have been due to histological processing. 9. It is concluded that axons are non-circular in vivo. The hypothesis that non-circularity allows axons to accommodate swelling during repetitive activity is discussed. Suggestions are made as to why γ axons may be more non-circular than α or group III axons in an anaesthetized cat immediately prior to fixation, and why α axons may be more non-circular than axons in groups I and II.

Journal ArticleDOI
TL;DR: The article as discussed by the authors claimed that Chicago is the "evangelical capital of the U.S.A." and cited a host of evangelical agencies in greater Chicago: mission boards, denominational offices, colleges, Bible institutes, seminaries, publishing concerns and youth organizations.
Abstract: In April of 1952 an article in Christian Life magazine proclaimed Chicago “the evangelical capital of the U.S.A.” To back this claim, editor Russell T. Hitt cited a host of evangelical agencies in greater Chicago: mission boards, denominational offices, colleges, Bible institutes, seminaries, publishing concerns (including Christian Life itself) and youth organizations. In total, the author mentioned over one hundred different agencies such as Youth For Christ International, the Slavic Gospel Association, Scripture Press and the Swedish Covenant Hospital. At first glance, the article appears to present a confusing list of unrelated organizations, but closer inspection reveals a coherent pattern.

Journal ArticleDOI
TL;DR: The inhibition of MAO activity by Triton X-100 after preincubation at 37° was found to be irreversible, and Sodium deoxycholate and SDS were also found to inhibit the activity ofMAO after pre incubation with the enzyme at37°.

Journal ArticleDOI
TL;DR: Combined measurements of density and dielectric permittivity have been made for six n -alkanes from n -pentane to n -decane at temperatures from −25 to 100 °C and a t various pressures up to 300 MPa as mentioned in this paper.
Abstract: Combined measurements of density and dielectric permittivity have been made for six n -alkanes from n -pentane to n -decane at temperatures from — 25 to 100 °C and a t various pressures up to 300 MPa. The molecular polarizability falls with increase in density in a nonlinear fashion. It displays a temperature effect whose magnitude is alternately large and small in the odd and even numbers of the series. The density data have been extensively compared with other sources, revealing significant devergences. The possibilities for an equation of state based on combined e, ρ measurements are discussed.

Journal ArticleDOI
TL;DR: For many years, study of the defect state of oxide crystals was overshadowed by activity in the alkali halides, however, during the last decade, work on oxides has emerged as an important field of research as discussed by the authors.
Abstract: For many years, study of the defect state of oxide crystals was overshadowed by activity in the alkali halides. However, during the last decade, work on oxides has emerged as an important field of ...

Journal ArticleDOI
01 Nov 1980-Genetics
TL;DR: Three mutants of Saccharomyces cerevisiae that divide at approximately half the size of the wild type are isolated in which the small size at bud initiation is due to a mutation in a single nuclear gene.
Abstract: The isolation of mutants of Saccharomyces cerevisiae that divide at approximately half the size of the wild type is described. Three mutants have been isolated in which the small size at bud initiation is due to a mutation in a single nuclear gene.

Journal ArticleDOI
TL;DR: Four examples of infiltrating gastric tumours which had light microscopic features suggestive of carcinoid or oat‐cell carcinoma are documented and it is felt that increased recognition of poorly differentiated endocrine tumours of the stomach might be of prognostic and therapeutic importance.
Abstract: Four examples of infiltrating gastric tumours which had light microscopic features suggestive of carcinoid or oat-cell carcinoma are documented. Histological and ultrastructural findings indicated that these tumours were atypical carcinoids. A spectrum of endocrine cell neoplasia in the stomach analagous to that observed in the bronchus is postulated. It is felt that increased recognition of poorly differentiated endocrine tumours of the stomach might be of prognostic and therapeutic importance.

Journal ArticleDOI
TL;DR: Two serotypes of epidermolytic toxin were purified from culture filtrates of different strains of Staphylococcus aureus, each containing no cystine and one methionine, but type ii contains no tryptophan, whereas type i has 1 mol/mol protein.

Journal ArticleDOI
J. J. Dinn1, D. G. Weir1, Shaun R. McCann1, B. Reed1, P. Wilson1, John M. Scott1 
TL;DR: The findings indicate that nitrous oxide directly inhibits the folate dependent methionine synthetase reaction, which ultimately results in ‘methyl group deficiency’ with consequent defective remethylation of essential constituents of nerve tissue.
Abstract: The pattern of degeneration induced in the spinal cords and peripheral nerves of 4 monkeys exposed to nitrous oxide resembles subacute combined degeneration found in man with untreated vitamin B12 deficiency. Our findings indicate that nitrous oxide directly inhibits the folate dependent methionine synthetase reaction. This ultimately results in ‘methyl group deficiency’ with consequent defective remethylation of essential constituents of nerve tissue. The implications of the methyl group deficiency hypothesis are examined and its relationship to the haematological and neurological status of patients with vitamin B12 deficiency are discussed.


Journal ArticleDOI
15 Mar 1980-Cancer
TL;DR: Both the light and electron microscopic findings strongly support an origin from the intercalated duct of esophageal mucus glands and the paucity of gland lumina may represent a lesser degree of differentiation which would accord well with the known biological aggressiveness of the tumor at this site.
Abstract: The light and electron microscopic appearances of adenoid cystic carcinoma of the esophagus are presented. Typical light microscopic features of adenoid cystic carcinoma were seen, but a unique additional feature was the presence at one edge of the tumor of gland-like structures lined entirely by tumor cells and opening onto an intact esophageal epithelium. Electron microscopy showed cystic spaces containing replicated basement membrane surrounded by epithelial cells with occasional myoepithelial cells at the interface. Rare lumina were seen between the cells with microvilli projecting into them. Occasional epithelial cells contained granules of neurosecretory tape. Both the light and electron microscopic findings strongly support an origin from the intercalated duct of esophageal mucus glands. The paucity of gland lumina may represent a lesser degree of differentiation which would accord well with the known biological aggressiveness of the tumor at this site.

Journal ArticleDOI
TL;DR: Exact and approximate bounds for the mean blocking time in exponential open queue networks with finite intermediate waitingroom and the condition for stability in the two-stage networks are derived.

Journal ArticleDOI
TL;DR: Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis, and prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.
Abstract: Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis. Consistent haematological changes were absent. One mare had lymph node involvement but no neoplastic lesions in the viscera. Microbiological examination of tumour tissue showed coryneform bacteria; there was no evidence of C-type or lytic viruses or of reverse transcriptase. Prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.

Journal ArticleDOI
TL;DR: The effect of acute duodenal infusion of 99Mo-labelled sodium tetrathiomolybdate on caeruloplasmin (ferroxidase) was examined in sheep and the diamine oxidase activity of this enzyme with respect to two substrates, p-phenylenediamine and o-dianisidine was inhibited.
Abstract: 1. The effect of acute duodenal infusion of 99Mo-labelled sodium tetrathiomolybdate on caeruloplasmin (ferroxidase; EC 1.16.3.1) was examined in sheep. The diamine oxidase activity of this enzyme with respect to two substrates, p-phenylenediamine and o-dianisidine (both at their apparent Km concentrations) was inhibited. 2. The 99Mo appeared rapidly in plasma and was at first present predominantly in a trichloroacetic acid insoluble form; inhibition of oxidase activity was related to the levels of TCA-insoluble Mo. The behaviour of the copper prosthetic groups of caeruloplasmin was altered since some plasma Cu precipitated with the protein fraction after TCA treatment. The appearance of TCA insoluble Cu was related to the level of TCA-insoluble 99Mo and corresponded to the inhibition of diamine oxidase activity.

Journal ArticleDOI
TL;DR: In this article, the uniqueness of solutions to a model set of equations describing the temperature and flow of cold (or sub-temperate) glaciers is considered. But the model is based on Fowler & Larson (1978) and the only real simplification which is made is that of taking small Peclet number (or Graetz number), which implies that advective heat transport is negligible.
Abstract: Summary We consider the uniqueness of solutions to a model set of equations describing the temperature and flow of cold (or sub-temperate) glaciers. These equations are based on the model developed by Fowler & Larson (1978), and incorporate the essential features of a free surface boundary, free melting boundary, and a fully non-Newtonian flow law. The only real simplification which is made is that of taking small Peclet number (or Graetz number), which implies that advective heat transport is negligible. Parametric estimates indicate that this is unrealistic, but nevertheless it represents a formally self-consistent way of effectively adopting a ‘slab’ model, while avoiding the inherent disadvantages of such models. Since the possibility of non-uniqueness is associated with the non-linear viscous heating term, we expect that non-zero advection of heat will only affect the results quantitatively, but not qualitatively. We find that for the various kinds of basal boundary condition which can occur, the solutions for the temperature (and hence the flow field) are unique, with the possible exception of regions where the basal ice is temperate and sliding, but the rest of the glacier is cold. In such regions one can have up to three solutions (even with the exponential approximation to the Arrhenius term), and such solutions can exhibit hysteretic instability: however, we then show that such multiple solutions must transgress the condition that the ice be below its freezing point, and hence they are not relevant in the present study. We therefore conclude that the solutions are unique, and so the non-linear heating term is unlikely to cause surge-like instabilities in real glaciers (or ice sheets). This does not preclude the possibility that the unique solution is linearly unstable to infinitesimal perturbations: such an instability might also lead to surging states, but not in the explosive manner that non-uniqueness would suggest.

Journal ArticleDOI
TL;DR: This paper assess the empirical likelihood, as opposed to the theoretical possibility, of such perversities and conclude that cases of a perverse price-output response consistent with dynamic stability of the model, though theoretically possible, are unlikely to arise in practice.

Journal ArticleDOI
TL;DR: Growth of Staphylococcus aureus in chambers was slower in vivo than in vitro, and in vivo the stationary phase was more prolonged and growth attained a lesser density than it did in vitro.

Journal ArticleDOI
TL;DR: A primary role for membrane damage is suggested in the mechanism of heat killing of exponentially growing yeast cells by exposure to 52°C, which increased markedly as the growth temperature was increased.
Abstract: The resistance of exponentially growing yeast cells to killing by exposure to 52 degrees C increase markedly as the growth temperature was increased Identical killing curves were obtained for cells suspended in growth medium or in 09% saline Cells resistant to killing at 52 degrees C were quite sensitive to killing at slightly higher temperatures These results suggest a primary role for membrane damage in the mechanism of heat killing

Journal ArticleDOI
TL;DR: Gastric acid secretion and gastrointestinal hormone levels were measured in healthy non-diabetic subjects after metformin treatment and it is suggested that met formin acts as a eak histamine agonist.
Abstract: Gastric acid secretion and gastrointestinal hormone levels were measured in healthy non-diabetic subjects after metformin treatment (1.5 g/day). The maximum acid output was increased from 15.7 ±3.9 mmol/h (mean±SEM) to 30.0±7.1 mmol/h (p < 0.05) and the peak acid output was increased from 16.4±4.1 mmol/h to 31.7±7.2 mmol/h (p < 0.05) after two weeks treatment. Serum insulin, gastric inhibitory polypeptide and secretin levels were normal. After treatment for one week, however, there was a significant increase in fasting vasoactive intestinal peptide (VIP) from 83±6 ng/l to 102±9 ng/l (p < 0.02) and in stimulated VIP from 58±5 ng/l to 79±5 ng/l (p < 0.05). Stimulated glucagon-like immunoreactivity (GLI) was also increased from 82±10 ng/l to 174±24 ng/l (p < 0.01) after one week's treatment. It is suggested that metformin acts as a eak histamine agonist.