Showing papers by "Memorial University of Newfoundland published in 1972"
TL;DR: Although the structures and textures of spilites and keratophyres are comparable to those of fresh lavas, recent work has established that they did not acquire their present mineralogy at the time of extrusion as discussed by the authors.
Abstract: Although the structures and textures of spilites and keratophyres are comparable to those of fresh lavas, recent work has established that they did not acquire their present mineralogy at the time of extrusion. Furthermore, the compositions of many analyzed samples of spilites and keratophyres are shown to lie outside a ‘spectrum’ of compositions of all comparable fresh igneous rocks. A later metamorphism has therefore been responsible for their formation and has commonly been accompanied by metasomatism. This possibility of later metasomatism must be appreciated before conclusions are drawn that are based upon analysis of rocks of a spilitic or keratophyric mineralogy. This applies to age-dating and to analytically based petrographic and petrogenetic conclusions.
226 citations
TL;DR: Sets of growth lines in the shell of Clinocardium nuttalli are extinguished every 13 or 14 increments only to be replaced by other sets, half an increment out of phase with the first.
Abstract: Sets of growth lines in the shell of Clinocardium nuttalli are extinguished every 13 or 14 increments only to be replaced by other sets, half an increment out of phase with the first. This can be explained only by assuming that the lines are deposited during periods of exposure at low tide. The average duration of an increment is 24 hours and 50 minutes.
119 citations
TL;DR: Investigation of the decomposition of steroid and other organic hydroperoxides by the microsomal fractions of rat liver and bovine adrenal cortex revealed that the 17α-hydroperoxide derivatives of progesterone, pregnenolone, and allopregnanolone were very effective substrates.
95 citations
70 citations
TL;DR: Cholesterol 25-hydroperoxide would not function as a substrate and is the first hydroperoxide so far reported that cannot be metabolized by glutathione peroxidase.
45 citations
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27 citations
TL;DR: In this paper, three phases of volcanic activity, older, middle, and younger, are represented on Moheli and two separate petrochemical variation trends are proposed, namely a low-pressure trend from melanephelinite through nephelinites and trachyte to phonolite, caused by fractionation of olivine, clinopyroxene, and (later) feldspar.
Abstract: Three phases of volcanic activity, older, middle, and younger, are represented on Moheli. The island was originally a large central-type shield volcano, made up of ancient lava flows, but it presently has an elongate form reflecting fissure eruptions of intermediate phase lavas. Silica-undersaturated lava, alkalic basalt, basanite and melanephelinite, with lesser amounts of nephelinite, trachyte, and phonolite are the main rock types found on Moheli. Intrusive equivalents occur in the form of alkali gabbro, theralite, and ijolite. Inclusions of ultramafic rocks are common, and rare sandstone inclusions are also present. Two separate petrochemical variation trends are proposed, namely a low-pressure trend from melanephelinite through nephelinite and trachyte to phonolite, caused by fractionation of olivine, clinopyroxene, and (later) feldspar. A high-pressure trend from alkali basalt through basanite to melanephelinite probably results from variable (low) degrees of partial melting of upper mantle material. A striking low potassium content and consequent low K:Rb ratios in the basanite are tentatively explained as resulting from fractionation of amphibole.
27 citations
26 citations
TL;DR: In this paper, the same authors analyzed nine Alaskan valley glaciers eroding five different bedrock types and found that the streams are similar in that Ca is the most abundant ion of those analyzed and the cold waters have a basic pH.
Abstract: Analysis of meltwater streams from nine Alaskan valley glaciers eroding five different bedrock types showed: (1) the streams are similar in that Ca is the most abundant ion of those analyzed and the cold waters have a basic pH, and (2) total (Na + K + Ca + Mg + Si) and suspended load concentrations vary in streams from glaciers on different bedrock types, from different glaciers on similar bedrock, and from the same glaciers during different sampling periods. The results indicate bedrock type is probably not the most important factor controlling the quantity of total (Na + K + Ca + Mg + Si) in glacial meltwater and suspended load concentration is controlled by stream conditions at the time of sampling. Comparative chemistry of aliquots of water samples, millipore filtered immediately upon collection and after 2 to 120 days storage prior to filtration, indicate ions are introduced to meltwater by partial dissolution of suspended load and that in terms of absolute concentrations more Ca than other ions is introduced in this manner. Ca was also found to be the most readily mobilized ion from suspended load in samples from three of the streams. These experimental results for Ca, plus the greater abundance of Ca than other ions in the meltwater, suggest a relation between ions and suspended load in glacial streams. The results also point out the necessity of immediate filtration of samples for accurate determinations of the chemical composition of water.
TL;DR: This paper found that the contrast thresholds for a short-line test grating were relatively higher if the subject had previously viewed a high-contrast grating with short lines of equal length to the test grates than if they viewed an adapting grating having longer lines, consistent with the view that there are detectors sensitive to line length in the human visual system.
TL;DR: This chapter discusses avian blood coccidians focusing on two distinct groups of blood-dwelling stages of coccidia: small nonpigmented nucleophilic parasites of mononuclear cells in the viscera and peripheral circulation and typical adeleine haemogregarines, such as those that parasitize the blood cells of vertebrates during the course of the life cycle.
Abstract: Publisher Summary This chapter discusses avian blood coccidians focusing on two distinct groups of blood-dwelling stages of coccidia: (1) small nonpigmented nucleophilic parasites of mononuclear cells in the viscera and peripheral circulation and (2) typical adeleine haemogregarines, such as those that parasitize the blood cells of vertebrates during the course of the life cycle. Check-list of avian hosts of both groups of parasites is given. These parasites are considered in separate sections as atoxoplasms and adeleine haemogregarines. There are considerable morphological differences between the atoxoplasms seen in avian monocytes and the classical Lankesterella minima, which inhabits erythrocytes of frogs. Atoxoplasms have been studied by electron microscopy. The ultrastructure revealed is markedly similar to that of Toxoplasma and the other einieriid coccidian, such as Eimeria species and Isospora. In some instances, especially where the host red blood corpuscle was partly disintegrated, the haemogregarine could clearly be seen to have a sharply reflected “tail.”
TL;DR: A recent geological mapping and compilation and publication of the first geological map of Labrador as mentioned in this paper indicate that three broad groups of Precambrian supracrustal rocks, each separated in time by a principal orogenic cycle, can be recognized in coastal Labrador.
Abstract: RECENT geological mapping and the compilation and publication of the first geological map of Labrador1 indicate that three broad groups of Precambrian supracrustal rocks, each separated in time by a principal orogenic cycle, can be recognized in coastal Labrador (Table 1).
TL;DR: In this article, the magnetic properties of drill chips are found to reside predominantly in magnetite, probably in deuterically oxidized primary titanomagnetite grains in the rock.
TL;DR: Dissolution of cell wall material has been recorded in the cortical and provascular elements of the quiescent root meristems of Allium cepa L. bulbs, indicating elaboration of massive rough endoplasmic reticular elements which directly participate in the breakdown process.
TL;DR: Analysis of vertebrate protein sequences totalling 4040 residues shows that amino acids with a high proportion of codons ending in C occur with significantly reduced frequency before amino acids whose codons start with G.
Abstract: Analysis of vertebrate protein sequences totalling 4040 residues shows that amino acids with a high proportion of codons ending in C occur with significantly reduced frequency before amino acids whose codons start with G. This effect is not shown by “control” bacterial protein sequences. The consequent implication of shortage of XXC. GXX codon pairs in vertebrate messenger RNA is discussed in relation to the extreme rarity of the base doublet CpG in vertebrate DNA.
TL;DR: The indications are that the life-history of the species is similar in other parts of its range, although the longevity of the foliose stage may vary with geographical location and depth.
Abstract: The life-history and phenology of T. pennyi, regarded as the only species of Turnerella in the north Atlantic Ocean, are described on the basis of culture, cytology and field investigations. In Newfoundland and Labrador, heteromorphic phases occur: tetraspores from an encrusting tetrasporophyte resembling Cruoria arctica/rosea give rise to a similar perennial sterile phase from which the foliose T. pennyi phase arises directly. These foliose plants are dioecious gametophytes. The male gametophyte, reported for the first time, bears spreading spermatangial sori over most of its surface. Old cystocarpic plants may exhibit in situ germination of carpospores. Chromosome counts show that n = 18–20; 2n = 36–40. The indications are that the life-history of the species is similar in other parts of its range, although the longevity of the foliose stage may vary with geographical location and depth. Regeneration of old loose-lying plants readily occurs.
TL;DR: The Notre Dame Bay area of north central Newfoundland is rapidly becoming a critical area for understanding the Appalachian mountain belt within the framework of plate tectonics1,2,3 as discussed by the authors.
Abstract: THE Notre Dame Bay area of north central Newfoundland is rapidly becoming a critical area for understanding the Appalachian mountain belt within the framework of plate tectonics1–4. Although the Ordovician volcanic rocks in the region are of critical importance, a lack of detailed information has already led to contrasting interpretations of their origin both in ocean ridge1,2 and island arc3 environments.
TL;DR: The reaction of germanium(IV), tin(II) and tin(IV) halides with bis(dicarbonyl-π-cyclopentadienyliron) and bis(carbonylπ-κ-cycledienylnickel) has been used to prepare CpFe(CO)2GeX3 (X = Cl, Br, and I), CpNi(CO)-MX3 (M = Ge, X = Cl and I; M = Sn, X, Cl, and Br; X = Br; M
TL;DR: The elemental composition of three lots of vitamin-free Casamino Acids (Difco) was determined using X-ray fluorescence, atomic absorption, and colorimetric techniques.
Abstract: The elemental composition of three lots of vitamin-free Casamino Acids (Difco) was determined using X-ray fluorescence, atomic absorption, and colorimetric techniques.
TL;DR: In this article, the data from a number of studies of plastic behavior of anisotropic metal sheets in simple and biaxial tension are reinterpreted, and it is shown that when direct stresses act along the principal directions of the anisotropy, Hill's definition of the generalized stress and strain can be used to predict the material behaviour in biaaxial tension using the information from simple tension tests.
TL;DR: This paper presents the impedance and admittance forms of diakoptic solution of the load-flow problem on the basis of graph- theoretic concepts that does not assume a fixed slack bus voltage but takes into account the equation for total transmission line losses as an integral part of the scheme.
Abstract: This paper presents the impedance and admittance forms of diakoptic solution of the load-flow problem on the basis of graph- theoretic concepts. The formulation does not assume a fixed slack bus voltage but instead takes into account the equation for total transmission line losses as an integral part of the scheme. Finally, test data based on this alternative formulation are presented for purposes of comparison With existing methods.
TL;DR: It appears that sponge cell movement prior to aggregation is not random, and the application of a two-dimensional random walk theory for unequal step length to aggregating sponge cells is described.
TL;DR: Regeneration of the host cells was observed, a phenomenon not previously reported in the fungal parasitism of other filamentous benthic marine algae.
Abstract: Olpidiopsis antithamnionis n. sp. (Oomycetes, Olpidiopsidaceae) parasitic on Antithamnion floccosum (O. F. Mull.) Kleen (Rhodophyta, Ceramiaceae) is described from three sites in Newfoundland, Canada, and from culture.
TL;DR: The decomposition of pregnene 17α-hydroperoxide by adrenocortical microsomal fractions is investigated in light of previous suggestions that steroid hydroperoxides may be intermediates in biological hydroxylation reactions.
TL;DR: In this paper, the NMR spectra of 2-benzylpyrrole and 2-phenyl pyrrole complexes were analyzed in terms of electronic effects transmitted through the σ-electron system and in ring current effects.
TL;DR: The data reveal that the administration of aldosterone in viva elevated the activities of both Mg*+ and Mn” dependent i.e. forms I and II, RNA polymerases, and it is concluded, that RNA polymerase is one of the sites involved in the mechanism of action of a Aldosterone.