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Asphaltene constituents are, by definition, a solubility class that is precipitated from petroleum, heavy oil and bitumen and therefore do not have a single, unique structure or specific molecular weight. When dispersed in petroleum, asphaltene constituents appreciably increase petroleum viscosity and adversely affect the productivity of oil wells and/or the means of refining. Owing to the changes in the composition of petroleum as well as variations of temperature, pressure, petroleum (a dynamic stable system) may be disturbed and asphaltene constituents are likely to be precipitated. The purpose of this review is to examine the methods by which asphaltene deposition can be predicted or determined and hence methods by which deposition can be mitigated.

Petroleum is a complex but delicately balanced system that depends upon the relationship of the constituent fractions to each other and the relationships are dictated by molecular interactions. Thus, some aspects of recovery and refining chemistry, especially the chemistry of the deposition of asphaltenic material (degradation or reaction products of the asphaltene constituents and the resin constituents), can be proposed by virtue of the studies that have led further knowledge of the nature of asphaltene constituents and the resin constituents and particularly the nature of their interaction in crude oil.

The definition of the nonvolatile constituents of petroleum (i.e., the asphaltene constituents, the resin constituents, and, to some extent, part of the oils fraction insofar as nonvolatile oils occur in residua and other heavy feedstocks) is an operational aid. It is difficult to base such separations on chemical or structural features. This is particularly true for the asphaltene constituents and the resin constituents, for which the separation procedure not only dictates the yield but can also dictate the quality of the fraction. For example, the use of different hydrocarbon liquids influences the yield by a considerable factor. The technique employed also dictates whether or not the asphaltene contains coprecipitated resins. This is based on the general definition that asphaltene constituents are insoluble in n-pentane (or in n-heptane) but resins are soluble n-pentane (or in n-heptane). The results of structural studies of asphaltene constituents are moving away from the older ideas that asphaltene constituents contained large polynuclear aromatic systems and there are a variety of functional types that also play a role in asphaltene behavior. The stability of petroleum is dependent upon the molecular relationships of the asphaltene and resin constituents and the balance with the other constituents of petroleum. Thus, the stability of petroleum can be represented by a three-phase system in which the asphaltene constituents, the aromatic fraction (including the resin constituents), and the saturate fraction are in a delicately balanced harmony. Various factors, such as oxidation, can have an adverse effect on the system, leading to instability or incompatibility as a result of changing the polarity, and bonding arrangements, of the species in crude oil.

The dynamics of bubble solitons in two-dimensional isotropic antiferromagnets, inhomogeneously doped so that the exchange integral Jbecomes position-dependent, is studied. In the usual continuum approximation, the system reduces to a nonlinear sigma model on a spacetime whose geometry depends on J(x). It is shown, both within the geodesic approximation, and by appealing to field theoretic conservation laws, that a bubble incident on a domain-wall inhomogeneity undergoes refraction in accordance with Snell's law, J?1being identified with the refractive index, and that sufficiently oblique impacts result in total internal reflexion. Possible applications of this phenomenon to the construction of bubble lenses and bubble guides (in analogy with fibre-optic cables) are considered.

It is shown that the topological discrete sine-Gordon system introduced by Speight and Ward models the dynamics of an infinite uniform chain of electric dipoles constrained to rotate in a plane containing the chain. Such a chain admits a novel type of static kink solution which may occupy any position relative to the spatial lattice and experiences no Peierls-Nabarro barrier. Consequently the dynamics of a single kink is highly continuum-like, despite the strongly discrete nature of the model. Static multikinks and kink-antikink pairs are constructed, and it is shown that all such static solutions are unstable. Exact propagating kinks are sought numerically using the pseudo-spectral method, but it is found that none exist, except, perhaps, at very low speed.

The low-energy, rotationally equivariant dynamics of nlumps on S2is studied within the approximation of geodesic motion in the moduli space of static solutions . The volume and curvature properties of are computed. By lifting the geodesic flow to the completion of an n-fold cover of , a good understanding of nearly singular lump dynamics within this approximation is obtained. The limit of large domain radius is examined and a prediction for the rate of collapse of coincident lumps in the plane extracted.

As permanent magnet materials have developed, attempts have been made to take advantage of their improved properties in medical applications. Uses of magnets in medical applications range from their simple use for retention, through orthopaedics and fracture healing, to magnetomotive artificial hearts and pioneering brain surgery, where magnets are used to guide catheters. Magnets also find use in applications such as magnetic resonance imaging (MRI) scanners and drug delivery systems. This overview, based on an extensive review of the literature, chronicles the development of magnets in medicine and summarises areas where future research will be beneficial.

In this double‐blind study, 301 patients with subjective and objective signs of sore throat were randomly assigned to flurbiprofen 8.75 mg (n=129), flurbiprofen 12.5 mg (n=43) or placebo (demulcent lozenge without active drug [n=129]). Efficacy was assessed by changes in subjective rating scales primarily after a single dose and also over a 4‐day period. Flurbiprofen 8.75 mg was superior to placebo in a number of efficacy parameters, notably throat soreness. Throat soreness was significantly reduced after 15 minutes (p<0.05), with effects sustained for at least 2 hours (p<0.05). Multiple dosing with flurbiprofen 8.75 mg lozenges continued to provide effective symptomatic relief over the 4‐day treatment period. The small sample size was considered contributory to the variable results obtained with flurbiprofen 12.5 mg lozenges, but overall these were not inconsistent with previous trials. Both treatments were tolerated well. Flurbiprofen 8.75 mg lozenges provide an effective and well tolerated treatment for sore throat.

THE LIFE OF CAPTAIN JAMES COOK by J. C. Beaglehole. 16 by 25 cm, xi and 760 pages, text figures, plates. Black, London 1974 (ISBN 0 7136 1382 3) $A16.00RURAL INDUSTRY IN THE PORT PHILLIP REGION 1835-1880 by L. J. Peel. 19 by 25 cm, xiv and 196 pages, text figures, tables. Melbourne University Press, Melbourne 1974 (ISBN 0 522 84064 7) $A15.00WAIKATO COROMANDEL KING COUNTRY REGION compiled by Town and Country Planning Division, Ministry of Works. 215 pages, text figures, tables, plates, and five folded maps in colour. Government Printer, Wellington 1973, $A8.75STUDIES OF CONTEMPORARY THAILAND edited by R. Ho and E. C. Chapman. 20 by 29 cm, xviii and 416 pages, tables, figures. Australian National University, Dept of Human Geography Publ. HG/8, Canberra 1973 (ISBN 0 7081 0294 8) $A6.00THE NATURAL LANDSCAPES OF CANADA by J. B. Bird. 17 by 26 cm. xvi and 191 pages, tables, text figures, plates. Wiley, Toronto 1972 (ISBN 0 471 07370 9) $A7.95ESSAYS ON THE SOCIAL GEOGRAPHY OF KAMPALA, UGANDA by M. A. Hirst. 72 pages. Geowest 2, 1974. Department of Geography, University of Western AustraliaTHE AGRICULTURAL SYSTEMS OF THE WORLD by D. B. Grigg. 15 by 23 cm. ix and 358 pages, text figures, tables. Cambridge University Press, London 1974 (ISBN 0 521 20269 8; 0 521 09843 2) $US7.95 limpURBAN AND REGIONAL AUSTRALIA by M. I. Logan et al. 18 by 24 cm. 151 pages, text figures, tables. Sorrett Publishing, Malvern, Vic. 1975 (ISBN 0 909752 21 4) $A7.95 limpURBANIZATION IN AUSTRALIA: The Postwar Experience edited by I. H. Burnley. 23 by 15 cm, xi and 248 pages, figures, illustrations, index. Cambridge University Press, Cambridge 1974 (ISBN 0 521 20250 7) $A13.50SUBURBAN GROWTH: Geographical Processes at the Edge of the Western City edited by J. H. Johnson. 15 by 23 cm, xv and 257 pages, text figures, tables. Wiley, London 1974 (ISBN 0 471 44390 5) $A11.90SYDNEY AT THE CENSUS, 1971: A SOCIAL ATLAS by J. R. Davis and P. Spearritt. 30 by 40 cm, vi and 117 pages, computer maps, descriptive test. Urban Research Unit, Australian National University, Canberra 1974 (ISBN 0 909778 11 6) $A7.50 limpMINERALS AND MEN by J. F. McDivitt and G. Manners. 18 by 26 cm, xiv and 175 pages, text figures, tables, plates. Johns Hopkins University Press, Baltimore 1974 (ISBN 0 8018 1536 3) $US7.50COMMUNITY RESPONSE TO COASTAL EROSION by J. K. Mitchell. 15 by 23 cms. xii and 209 pages, text figures, tables. University of Chicago, Dept of Geography Research Paper No. 156, Chicago 1974. $US5.00ENVIRONMENT-INDUSTRY CONFLICT. THE MANJIMUP WOODCHIP INDUSTRY PROPOSAL, SOUTHWESTERN AUSTRALIA by A. J. Conacher. 43 pages. Geowest 4, 1975. Department of Geography, University of Western Australia (ISBN 0 909678 04 9)BIOGEOGRAPHY AND ECOLOGY IN TASMANIA edited by W. D. Williams. 15 by 24 cm, x and 498 pages, text figures, tables, plates. Junk, The Hague 1974 (ISBN 9 06193 077 4)ARCTIC AND ALPINE ENVIRONMENTS edited by J. D. Ives and R. G. Barry. 18 by 24 cm, xviii and 999 pages, text figures, tables, plates. Methuen, London 1974 (ISBN 0 416 65980 2) $70.00THE MITCHELL BEAZLEY WORLD ATLAS OF BIRDS edited by C. H. Fry, J. J. M. Flegg et al. 24 by 30 cm. 272 pages, text figures, plates. Mitchell Beazley, London 1974 (ISBN 0 85533 042 2) $A30.00ENVIRONMENTAL GEOSCIENCE by A. N. Strahler and A. H. Strahler. 20 by 27 cm, ix and 575 pages. Hamilton Publishing, Santa Barbara 1973 (ISBN 0 471 83163 8)RATES OF DENUDATION IN SELECTED SMALL CATCHMENTS IN EASTERN AUSTRALIA by I. Douglas. 14 by 22 cm, x and 127 pages, tables, text figures. University of Hull Occ. Papers in Geography No. 21, Hull 1973 (ISBN 0 900 48047 5) £2.00AERIAL PHOTOGRAPHY IN ANTHROPOLOGICAL FIELD RESEACH edited by E. Z. Vogt. 24 by 24 cm, 194 pages, text figures, tables, plates. Harvard University Press, Cambridge, Mass. 1974 (ISBN 0 674 00626 7) $A20.95URBAN SOUTHEAST ASIA edited by G. Breese. 21 by 27 cm, v and 165 pages. Southeast Asia Development Advisory Group, Asia Society, New York 1973NATIONAL DEVELOPMENT POLICY AND URBAN TRANSFORMATION IN SINGAPORE by Yueman Yeung. 15 by 23 cm, x and 204 pages, text figures, tables, plates. Dept of Geography Research Paper No. 149, University of Chicago 1973. $US5.00CRIME RATES AS TERRITORIAL SOCIAL INDICATORS by D. M. Smith. 21 by 30 cm, 50 pages, text figures, tables. Dept of Geography, Queen Mary College College, University of London, Occasional Paper No. 1, 1974THE SPATIAL DYNAMICS OF CRIME by G. F. Pyle et al. 15 by 23 cm, x and 221 pages, text figures, tables. Dept of Geography Research Paper No. 159, University of Chicago 1974. $US5.00CHICAGO, METROPOLIS OF THE MID-CONTINENT by I. Cutler. 28 by 22 cm, 128 pages, illustrations. The Geographic Society of Chicago, Chicago 1973ATLAS OF ATLANTA: THE 1970's by M. A. Murray. 23 by 30 cm, xiii and 46 pages. University of Alabama Press, Alabama 1974. $US3.95HAWKERS IN HONG KONG by T. G. McGee. 226 pages, text figures, tables, plates. Centre of Asian Studies, University of Hong Kong, Occasional paper No. 17, 1974 (Library of Congress Catalogue Card No. 73 84618)THE EVOLUTION OF LOCAL GOVERNMENT AREAS IN METROPOLITAN AUCKLAND 1840-1971 by G. T. Bloomfield. 21 by 30 cm, xii and 175 pages, text figures and tables. Auckland University Press, Auckland 1973 (ISBN 0 19 647714 X) $A6.40PEOPLE AND PROPERTY IN NORTH MELBOURNE by K. Johnson. 20 by 29 cm, xvi and 240 pages, text figures, tables. Research School of Social Sciences Urban Research Unit Monograph, Australian National University Press, Canberra 1972 (ISBN 0 909778 10 8) $A3.00ENVIRONMENTAL QUALITY IN FOUR SYDNEY SUBURBAN AREAS by P. N. Troy. 20 by 29 cm, x and 131 pages, text figures, tables. Research School of Social Sciences Urban Research Unit Monograph, Australian National University Press, Canberra 1972 (ISBN 0 909778 10 8) $A3.00PEOPLE AND PROPERTY IN RANDWICK by M. Neutze. 20 by 29 cm, viii and 105 pages, text figures, tables. Research School of Social Sciences Urban Research Unit Monograph, Australian National University Press, Canberra 1971 (ISBN 0 909778 02 7) $A3.00URBAN POPULATION DENSITIES AND THE NEGATIVE EXPONENTIAL MODEL: A REVIEW by A. E. Brine. 21 by 30 cm, i and 59 pages. Working Paper No. 5, Dept of Geography, University of Western Australia 1975 (ISBN 0 909678 05 7)THE SMALL SHOP IN THE CITY by D. Sibley. 14 by 22 cm, viii and 52 pages, text figures, tables. Occ. Papers in Geography No. 22, University of Hull 1975 (ISBN 0 9004 8047 5) £1.20THE EVOLUTION OF URBAN CENTRALITY: ORIENTATIONS FOR RESEARCH by J. Gottmann. 21 by 30 cm, 44 pages, text figure. School of Geography Research Paper No. 8, University of Oxford 1974MAP PROJECTIONS FOR GEODESISTS, CARTOGRAPHERS AND GEOGRAPHERS by Peter Richards and Ron K. Adler. x and 174 pages, text figures, tables. North Holland Publishing Company, Amsterdam and London, second printing, 1974 (ISBN 0 7204 5007 1; 0 444 10362 7)THEMATIC MAPPING. 21 by 29 cm, 44 pages, plates. Bulletin 5, Div. of National Mapping, Dept of Minerals and Energy, Canberra 1975WARD MAPS OF UNITED STATES CITIES compiled by M. H. Shelley. 29 by 23 cm, v and 24 pages. Library of Congress, Washington 1975 (ISBN 0 8444 0143 9) $US1.18OUTLINE SCHEME OF ISRAEL COASTAL STRIPS edited by E. Efrat. 30 by 50 cm, iii and 50 pages, plates. Planning Dept, Ministry of Interior, Jerusalem 1974THE LANGUAGE OF TOPOGRAPHIC MAPS by D. S. Biddle et al. 21 by 29 cm, 121 pages, text figures, tables, plates. Jacaranda, Milton 1974 (ISBN 0 7016 0693 2)COUNTRIES OF THE WORLD. 950 pages, 163 maps. U.S. Department of State Gale Research Company, Detroit, U.S.A. 1974 (ISBN 0 8103 1047 3) SUS12.50ORBIS GEOGRAPHICUS 1968/1972 edited by E. Meynen. 12 by 17 cm, 361 pages. Part I. Steiner. Wiesbaden 1970. DM 36ORBIS GEOGRAPHICUS 1968/74 edited by E. Meynen. 12 by 17 cm, xx and 798 pages. Part II. Steiner, Wiesbaden 1974 (ISBN 3 315 01967 7) DM 68GUIDE TO GEOGRAPHICAL BIBLIOGRAPHIES AND REFERENCE WORKS IN RUSSIAN OR ON THE SOVIET UNION by C. D. Harris. 15 by 23 cm: xviii and 478 pages. Dept of Geography Research Paper No.' 164, University of Chicago 1975 (ISBN 0 89065 071 3) $US5.00

Abstract:The topology and geometry of the moduli space, M₂, of degree 2 static solutions of the ℂP¹ model on a torus (spacetime T₂ ×ℝ) are studied. It is proved that M₂ is homeomorphic to the left coset space G/G₀, where G is a certain eight-dimensional noncompact Lie group and G₀ is a discrete subgroup of order 4. Low energy two-lump dynamics is approximated by geodesic motion on M₂ with respect to a metric g defined by the restriction to M₂ of the kinetic energy functional of the model. This lump dynamics decouples into a trivial "centre of mass" motion and nontrivial relative motion on a reduced moduli space. It is proved that (M₂,g) is geodesically incomplete and has only finite diameter. A low dimensional geodesic submanifold is identified and a full description of its geodesics obtained.

It is proved that the moduli space of static solutions of the ℂP1model on spacetime Σ ×∝, where Σ is any compact Riemann surface, is geodesically incomplete with respect to the metric induced by the kinetic energy functional. The geodesic approximation predicts, therefore, that lumps can collapse and form singularities in finite time in these models.

The persistence of tritiated DNA ([3H]DNA) in the thyroids of rats given propylthiouracil (PTU) or PTU plus thyroxine was compared with that in control animals who received either no drugs or thyroxine alone. When only PTU was given, large goitres developed from which [3H]DNA was lost more rapidly than from thyroids of control animals. Administration of thyroxine with PTU led to only slight thyroidal enlargement, but the persistence of [3H]DNA was similarly reduced.The results suggested that PTU might have a toxic effect, reducing the lifespan of thyroid cells and this was further investigated using monolayer thyroid cultures.Thyroid-stimulating hormone (TSH) accelerated the incorporation of tritiated thymidine ([3H]TdR) into cultures, but when PTU was also given the uptake was retarded. PTU alone was less effective in inhibiting [3H]TdR incorporation.The persistence of [3H]DNA in thyroid cultures was unaffected by PTU and was decreased by TSH. When PTU and TSH were given together there was a greatly increased loss of isotope from the cells.

The circumstances of the setting up of the Sub-Committee for Soil-Stratigraphic Nomenclature are set out in the introduction to the report which follows. A draft report prepared by the Sub-Committee was considered by the Stratigraphic Nomenclature Committee at its meeting at Adelaide in August 1969. As a result of the decisions at that meeting copies of the draft report were sent to all divisional subcommittees of the Stratigraphic Nomenclature Committee so that they could submit their comments to the convener to pass on to the Soil-Stratigraphic Nomenclature Sub-Committee for further consideration. The Sub-Committee then modified the report in accordance with the comments received. Further comment is invited, and it is hoped that as a result it will be possible for provision for Soil-Stratigraphic units to be included in the next edition of the Code of Stratigraphic Nomenclature. The Society owes a considerable debt to the members of the Sub-Committee for Soil-Stratigraphic Nomenclature, Dr Brewer, Dr Crook and Mr Speight, for the time and trouble which they have taken in trying to evolve an acceptable system for nomenclature of Soil-Stratigraphic units.N. H. Fisher, Convener, Stratigraphic Nomenclature Committee.

Die Häufigkeitsverteilungen von Hangwinkeln wurden von einer Anzahl unabhängiger Arbeiten abgeleitet. Die meisten zeigen, im Logarithmus des Tangens des Hangwinkels ausgedrückt, fast normale (oder GAUSSCHE) Verteilungen, und ihre Standard-Abweichungen sind unabhängig von dem durchschnittlichen Hangwinkel. Die Bedeutung von engen Spitzen auf Histogrammen der Hangwinkelhäufigkeit, die als „charakteristischer Hangwinkel“ bezeichnet wurden, werden in Abweichungen von Modell-Verteilungskurven ausgedrückt. Es wird unter Berücksichtigung der Meßungenauigkeit und der Unvollständigkeit der Proben festgestellt, daß die Häufigkeit des Vorkommens dieser charakteristischen Hangwinkel selten so stark von der Modell-Kurve abweicht, um eine Diskussion über ihre Genese zu rechtfertigen. Es wird ferner festgestellt, daß die Logarithmus Tangens-Standardabweichung von Hangwinkeln ganzer Landschaften hauptsächlich in den Bereich von 0.30 bis 0.65 Logarithmus Tangens-Einheiten fällt. Werden besondere Gesteinseinheiten oder geomorphologische Einheiten zur Hanganalyse herangezogen, so fallen die Standardabweichungen zwischen 0.20 und 0.40 Einheiten. Sehr heterogene Landschaften haben mehrgipfelige Häufigkeitskurven, die in eingipfelige aufgeteilt werden können und von denen jede einen homogeneren Teil der Landschaft repräsentiert.

Rat chromosomes prepared from thyroid cells grown in culture did not differ from those described for other tissues of this species. The incidence of thyroid cells with abnormal chromosomes was not increased by giving propylthiouracil to rats for 15 weeks.The thyroid chromosomes were damaged by injection of 1–25 μc of 131I. The damage persisted in the unstimulated thyroid for 15 weeks.Administration of propylthiouracil to rats after 131I caused significant reduction in the frequency of thyroid cells with radiation-damaged chromosomes.

Lymphocyte chromosomes of untreated and thyrotoxic patients treated with radioactive iodine have been compared with those of control subjects studied concurrently. Untreated patients had a higher percentage of cells with more than 46 chromosomes. 131I-treated patients who were compared with controls within 2–3 months of therapy had significantly increased incidences of cells containing fewer than 46 chromosomes and cells with chromatid and chromosome aberrations. Patients examined 2–5 yr. after radioactive iodine treatment showed similar changes in lesser degree.

To establish the precision of anticoagulant control in the first three months after mechanical heart valve replacement, 53 patients from a consecutive series of 91 were telephoned and asked to read out their anticoagulation record. The levels of international normalised ratio (INR) were analysed by Rosendaal's method. Twenty‐nine per cent of patient days were spent with an INR in the recommended range of 3.0‐4.5. Warfarin dosage was increased at a median INR of 2.1 (interquartile range 1.7‐2.3), unchanged at 2.7 (interquartile range 2.3‐3.1) and decreased at 4.3 (interquartile range 3.6‐5.1). Anticoagulant control is poor in the first three months after mechanical heart valve replacement. Data on the INR at which warfarin dosage is changed suggest either that recommended guidelines are not being followed or a reluctance to increase the dosage in patients receiving inadequate anticoagulation.

We demonstrate that the geometric volume of a soliton coincides with the thermodynamical volume also for field theories with higher-dimensional vacuum manifolds (e.g., for gauged scalar field theories supporting vortices or monopoles), generalizing the recent results of Ref. [C. Adam, M. Haberichter, and A. Wereszczynski, Phys. Lett. B 754, 18 (2016).]. We apply this observation to understand Bradlow-type bounds for general Abelian gauge theories supporting vortices, as well as some thermodynamical aspects of said theories. In the case of SDiff Bogomolny-Prasad-Sommerfield (BPS) models (being examples of perfect fluid models) we show that the base-space independent geometric volume (area) of the vortex is exactly equal to the Bradlow volume (a minimal volume for which BPS soliton solutions exist). This volume can be finite for compactons or infinite for infinitely extended solitons (in flat Minkowski space-time). [ABSTRACT FROM AUTHOR]

We present here the results of a palaeomagnetic investigation of 87 dykes from the north-western area of the regional linear dyke-swarm of Skye, NW Scotland, as a further contribution to studies of the British Tertiary igneous province. Twenty per cent of the dykes are normally magnetized, as with the north Mull dyke swarm. Reversely magnetized dykes with very low inclinations are present, as they are in some previous studies of the province. There are groups of closely adjacent dykes in which the individual dykes of any one group have very similar directions of magnetization- ‘palaeomagnetic dyke groups’. The overall distribution of dyke-mean magnetizations is very far from being Fisherian. A mean pole position is not considered to be a useful expression of the results.

One problem in the application of the Skyrme model to nuclear physics is that it predicts too large a value for the compression modulus of nuclear matter. Here we investigate the thermodynamics of the BPS Skyrme model at zero temperature and calculate its equation of state. Among other results, we find that classically (i.e. without taking into account quantum corrections) the compressibility of BPS Skyrmions is, in fact, infinite, corresponding to a zero compression modulus. This suggests that the inclusion of the BPS submodel into the Skyrme model Lagrangian may significantly reduce this too-large value, providing further evidence for the claim that the BPS Skyrme model may play an important role in the description of nuclei and nuclear matter. [ABSTRACT FROM AUTHOR]