Showing papers by "University of Reading published in 1978"

A new look at the ω‐equation

Abstract: In the conventional quasi-geostrophic form of the ‘omega’-equation, the forcing of vertical velocity is usually expressed as the sum of two terms associated respectively with vorticity and temperature advection. Consideration of each term in isolation is misleading and there can be a large degree of cancellation. On the other hand, in Sutcliffe's development theory, this forcing is, in effect, represented by a single term. However, this is achieved at the expense of neglecting another term which is dominant in frontal regions. An investigation, based upon the governing equations, of the manner in which geostrophic balance tends to destroy itself, reveals a simple, concise, one-term representation of the geostrophic forcing of ageostrophic motion. Many of the traditional synoptic rules are then simple deductions from this theory. An application of the theory in the case of a rapidly developing system is demonstrated using a 700mb chart.

A new family of mathematical models describing the human growth curve

Abstract: A new family of mathematical functions to fit longitudinal growth data is described. All members derive from the differential equation dh/dt = s(t). (h1-h) where h1 is adult size and s(t) is a function of time. The form of s(t) is given by one of many functions, all solutions of differential equations, thus generating a family of different models. Three versions were compared. All were superior to previously described models. Model 1, in which s(t) was defined by ds/dt = (s1 - s)(s - s0) was especially accurate and robust, containing only five parameters to describe growth in stature from age two to maturity. Derived "biological" parameters such as Peak Height Velocity were very consistent between these three members of the family but, in some cases, differed signficantly from previous estimates.

The Life Cycles of Some Nonlinear Baroclinic Waves

Abstract: Some aspects of the nonlinear behavior of mid-latitude baroclinic waves are investigated by means of a series of integrations of the primitive equations with spherical geometry. Each integration has as initial conditions a balanced zonal flow perturbed by a small-amplitude disturbance of normal-mode form. Results are presented in detail for several zonal flows and perturbations which are confined initially to either zonal wavenumber 6 or zonal wavenumber 9. In each case a disturbance grows by baroclinic instability and develops a structure in some agreement with the usual synoptic picture of an occluding system. Its growth rate at low levels decreases more rapidly than that at higher levels, as found by Gall using a more severely truncated model, and upper-level amplitudes become larger relative to surface values than in the initial linear mode. This is more marked for wavenumber 6 than for wavenumber 9, and differences in linear structure are thus enhanced in the nonlinear regime. Barotropic pro...

Phonological recoding and lexical access

Abstract: Four experiments are reported that examine the effects of homophony (e.g., SAIL/SALE) on response latency in a lexical decision task. The results indicated that an effect of homophony was evident only if the nonword distractors consisted of legal, pronounceable strings (e.g., SLINT), but that this effect disappeared if the nonwords sounded like English words (e.g., BRANE). An optional encoding strategy is proposed to account for this differential effect. It is suggested that while both graphemic and phonemic encoding occurred simultaneously, naive subjects tended to rely on the outcome of the phonological route. However, when such reliance produced a high error rate (i.e., when the nonwords sounded like English words),. these subjects were able to abandon a phonological strategy and rely on the graphemic encoding procedure instead. Two further aspects of the results are of interest. First, the less frequent member of a homophone pair was slower when compared with a control item if the nonword distractors were of the SLINT type, but not different if they were of the BRANE type. The high-frequency members did not differ from their controls in either nonword environment. Second, in a homophone “repetition” experiment, the frequency order of presentation within pairs of homophones (i.e., the high-frequency member followed by the low-frequency member, or vice versa) had a substantial effect. A spelling recheck procedure and a response-inhibitory mechanism are postulated to incorporate these effects into a dual-encoding direct-access model of word recognition.

An Inequality for the Weights of Two Families of Sets, Their Unions and Intersections

Abstract: then ~(A) fi(B) < 7(A v B) cS(A A B) for all A, B ~ S, (2) where e(A) = ~(a~A) e(a) and A v B = {awb; aeA, b~B} and A A B = {ac~b; a~A, b~B} Since every distributive lattice can be embedded in the subsets of some set we get an immediate Corollary If S is a distributive lattice and (2) holds whenever A, B each contain exactly one point of S then (2) always holds Here S, A, B may be infinite Our theorem contains as special cases results of Anderson, Daykin, Fortuin, Ginibre, Greene, Holley, Kasteleyn, Kleitman, Seymour, West and others 1 We discovered it whilst guests at the Mathematisches Forschungsinstit ut Oberwolfach and thank all concerned for their kindness to us

Methanogenesis, fires and the regulation of atmospheric oxygen

Abstract: The Gaia hypothesis states that the composition, oxidation-reduction potential and the temperature of the Earth's lower atmosphere are modulated by and for the biota living on the surface (Lovelock, 1972; Margulis and Lovelock, 1974). A corollary is that atmospheric oxygen is presently regulated at about 21% for the dominant life forms today: vascular plants and metazoa. We suggest that the enormous annual production of methane (of the order of 10 14 mol) is directly related to the short term modulation of oxygen concentration. Atmospheric oxygen results from the burial of reduced carbon; methanogenesis and subsequent atmospheric oxidation of methane prevents that burial. We also present experimental work on the probability of ignition of vegetation as a function of increasing oxygen concentration (Watson, 1978). Both the experiments and consideration of the fossil record lead us to conclude that oxygen has been regulated by methane (and perhaps by N 2 O and others) at about 10–25% for very long periods relative to the atmospheric residence times of these reactive gases.

‘A Brute to the Brutes?’: Descartes' Treatment of Animals

Abstract: To be able to believe that a dog with a broken paw is not really in pain when it whimpers is a quite extraordinary achievement even for a philosopher. Yet according to the standard interpretaion, this is just what Descartes did believe. He held, we are informed, the ‘monstrous’ thesis that ‘animals are without feeling or awareness of any kind’. The Standard view has been reiterated in a recent collection on animal rights, which casts Descartes as the villain of the piece for his alleged view that animals merely behave ‘as if they feel pain when they are, say, kicked or stabbed’. The basis for this widely accepted interpretation is Descartes' famous doctrine of ‘animal machine’ (‘bete-machine’); a doctrine that one critic condemns as ‘a grim fortaste of a mechanically minded age’ which ‘brutally violates the old kindly fellowship of living things’.

Energy Spectra Predicted by Semi-Geostrophic Theories of Frontogenesis

Abstract: During the final stages of the formation of fronts, semi-geostrophic theory predicts kinetic and available potential energy spectra that closely approximate a −8/3 power law as a function of horizontal wavenumber.

Interionic potentials for alkali halides. I. Crystal independent shell parameters and fitted Born-Mayer potentials

Abstract: A consistent set of shell parameters for alkali halide crystals of both rocksalt and CsCl structures is reported. The fitting procedure, values of the parameters and their sensitivity are discussed. Short range interionic potentials are determined and are shown to give a good description of both static and dynamic properties of the crystals.

Mechanical Properties of Primary Feathers From the Pigeon

Abstract: The morphology of the primary feather shaft from the pigeon wing has been examined and its salient features noted. The cortex (outer wall) of the shaft appeared to be the most significant feature in relation to bending behaviour and was analysed quantitatively. A model that simulated bending of the shaft was made using this analysis and upon comparison of simulated results with observed bending behaviour it is shown that the shape and size of the cortex does indeed account for the majority of bending behaviour. The model does not include torsional effects and the effects of the pithy medulla and the transverse septa, but the magnitude of these effects is considered to be small in comparison with that of the cortex considered in simple bending. Differences in the shape of the cortex in the outermost primary and those proximal to it are shown to account for different mechanical properties and possible reasons for this are given. The shape and size of the cortex, as measured by its second moment of area, is shown to have some relation to the body weight of the bird.

Displacive calcite: Evidence from recent and ancient calcretes

Abstract: Experimental evidence and studies of several naturally occurring minerals suggest that displacive growth of crystals by the force of crystallization occurs. Although displacive calcite has been frequently described and discussed, its implications have been largely ignored. Evidence of displacive micrite and fibrous spar in calcretes was found through the use of macromorphologic and micromorphologic features, fabrics, and textures. The implications of this expansive growth are important in the identification and interpretation of cements and neomorphic calcite. The recognition of displacive calcite provides evidence of supersaturated precipitating solutions that could be of use in detailed facies analyses and diagenetic studies.

Stability of the Semi-Implicit Method of Time Integration

Abstract: The stability of the semi-implicit method of time integration of the primitive equations is examined when the actual temperature deviates from the reference profile about which the implicitly treated gravity wave terms are linearized. The stability criterion is shown in general to be much more stringent than might he assumed from a simple analytical solution. Instability may occur when there exists a region in which the static stability of the actual atmosphere differs significantly from that of the reference atmosphere, and for realistic actual profiles and commonly chosen reference profiles it is likely to arise at vertical resolutions that are little higher than those used in previous tests of the scheme. Stabilization is achieved either by an appropriate change of reference profile or by a modification of the time-averaging of gravity wave terms. Both may result in a small further reduction in gravity wave phase speeds. Alternatives are mentioned which give better phase speeds at the expense ...

The trial of the Templars

Abstract: On 18 March 1314, Jacques de Molay, Grand Master of the Templars, was burned at the stake. For almost two centuries, the knights of the Order of the Temple had flourished during the Crusades in Palestine and Syria, and in the West, notably in France. But in 1307, the Templars in France were arrested by King Philip IV's officials in the name of the Inquisition, their property seized and the men charged with serious heresies, including the denial of Christ, homosexuality and idol worship. Confessions, extracted under torture, were brought before royal and papal tribunals, but in 1310 a number of Templar brothers mounted a defence of their Order, refuelling the controversies which continued for a further four years before the final executions. Malcolm Barber's fascinating account, assessing the charges brought against the Order, once again puts the Templars on trial.

The influence of habit formation on modal choice —a Heuristic model

Abstract: Most modal split models have been based on the assumption of rational behaviour in an individual's choice evaluation of the generalised costs of modal alternatives. This paper integrates conceptual and empirical information from a wide range of sources and points towards an alternative way of looking at modal choice. The main conclusion is that the car is usually perceived as the superior mode for vehicular travel and that the potential user is committed to its use largely through the act of purchasing it. The conceptual structure of a sequential modal split model is outlined as one that is based on a four-stage decision-making framework which considers the role of learning and habit-formation. In the conclusion, the implications of this approach are considered in terms of the conventional modal split and trip generation submodels, and certain policy measures are assessed.

Continental Rifting and Mantle Degassing

Abstract: Various lines of evidence have previously revealed the necessity for a vapour phase as an active ingredient of continental rift valley magmatism. Further constraints are now placed on the magmatology by the consistently low H2O contents of natural peralkaline felsic glasses. The H2O data confirm that these “highly evolved” liquids cannot be the products of closed system fractional melting or crystallization. They show, too, that the vapour coexisting with rift valley magmas must be deficient in H2O. The vapour must be strongly reducing, with high concentrations of carbon and halogen gases, and probably nitrogen. Rift valley magmas result from the fluxing action of this vapour as it escapes from the deep mantle and passes through the lithosphere segment below the rift. Initially, the vapour produces metasomatic carbonates, and halogen bearing silicates in the upper mantle and lower crust: subsequently it buffers the activities of Na, Fe, Si, F and CI, and trace elements in the ensuing magmas. The physical expression of the activity is, first, metasomatic and thermal uplift: followed by devolatilization, melting, eruption and subsidence as the flux cycle climbs through the lithosphere.

Analysis of the v 3 and v 1 infra-red bands of SiH4

Abstract: The high-resolution infra-red spectrum of SiH4 in the region 2101 cm-1 to 2265 cm-1 has been analysed. Most of the lines observed have been assigned to transitions of the v 3 and v 1 bands of the abundant isotopic species 28SiH4. The v 1 band is formally forbidden in the infra-red, but a vibration-rotation interaction between v 1 and v 3 lends intensity to the v 1 transitions. The spectrum has been fitted by diagonalizing the v 3 = 1 and v 1 = 1 hamiltonians coupled by the vibration-rotation interaction term. 500 transitions have been fitted with an overall standard deviation of 0·007 cm-1, using only 15 adjustable parameters (ten in the v 3 = 1 hamiltonian, four in the v 1 = 1 hamiltonian, and one interaction coefficient). The calculated intensities are also in good agreement with experiment. Transitions of the other isotopic species 29SiH4 and 30SiH4 have also been observed, but these spectra have not been analysed in detail.

Effects of irradiance and water supply on grain development in wheat

Abstract: SUMMARY The effects of two levels of irradiance and of water supply on grain development in two cultivars of winter wheat were studied by imposing treatments during the phases of cell production and cell expansion in the endosperm. The storage capacity of the grain was determined by cell number in the endosperm, which was reduced by both treatments during the cell production phase. Changes in cell number caused by the treatments were due to changes in the rate of production of cells; the duration of the cell production phase was constant. Weight per grain at maturity was proportional, both within and between cultivars, to the number of endosperm cells, except when treatments altered the supply of assimilate to the grain during the cell expansion phase. Reducing irradiance and water during the cell expansion phase decreased the rate of accumulation of dry matter in the grain and reduced weight per grain at maturity, with no effect on the duration of grain filling. Shrivelled grain resulted from a failure of the endosperm cells to fill completely, and was characterised by a reduction in the number of ‘B’-type starch granules.

On lamellar organization in certain polyethylene spherulites

Abstract: The lamellar structure of certain polyethylene spherulites grown very slowly at low supercoolings (regime I crystallization) has been exposed by using new techniques. A highly regular texture is found whose main element is ridged sheets of alternating {201} facets, ca. 1 pm wide, growing outwards with b as spherulitic radius. The first-formed sheets enclose columns of melt leading to the lateral segregation of slower crystallizing species and eventually to mimicry of a fibrous habit with a breadth and cross section controlled by the facet width. Although the morphology is similar to that expected according to the theory of Keith & Padden (1963), the facet width is ca. 10~5 of their characteristic length Apparently additional factors need to be invoked to explain spherulitic crystallization under conditions of extremely slow growth. {201} facets agree with earlier predictions but it is considered that folds cannot lie exclusively in {200} planes. The sectored morphology with its regular geometry indicates that folds have a preferred shape and that fold surfaces are ordered to an extent. The degree of ordering decreases for lower crystallization temperatures and for longer molecules.

The effects of heavy metal ions on Ca2+ ATPase extracted from fish gills

Abstract: 1. 1. The gills of the freshwater fish Rutilus rutilus have been shown to contain a subcellular membrane fraction which is rich in the enzyme Ca2+ ATPase. 2. 2. The enzyme is maximally activated by Ca2+ or Mg2+ ions at a concentration of about 2 mM but is not affected by Na+ or K+ ions or by ouabain. 3. 3. In vitro the enzyme is inhibited by Cu2+, Pb2+, Zn2+ and Hg2+ ions at concentrations below 10 μM. 4. 4. Copper ions at concentrations below 0.2 μM appear to induce the formation of additional enzyme units when applied to fish gills in vivo.

Subtidal flat-pebble conglomerate from the Upper Devonian of Poland; a multiprovenant high-energy product

Abstract: Calcirudites in the Upper Devonian (Frasnian) of Central Poland are often couplets with a laminated intrapelsparite upper part and a lower section of intraformational calcarenitic and micritic flat pebbles. The pebbles are associated with bioclasts derived from 3 offshore environments: I, a fully marine area (echinoderms, rugose and tabulate corals, brachiopods, trilobites and conodonts); II, phytogenic banks (globose stromatoporoid stromatolites and Renalcis); III, restricted lagoons (ramose stromatoporoids, calcispheres, ostracodes and peloids). Many of the flat pebbles are only slightly displaced and had been partially cemented before being reworked. The depositional environment was subtidal. The considerable size of the flat pebbles and the complex nature of the surrounding matrix suggest that storm surges or tsunami may have disrupted beds and led to channelling and pebble formation.

The determination of the component oligosaccharides of lupinseeds by high pressure liquid chromatography

Abstract: A simple rapid method is reported for the analysis of oligosaccharides in lupinseeds. The procedure involves extraction of the ground, defatted seeds with aqueous methanol, precipitation of protein with Carrez solution and subsequent analysis using high pressure liquid chromatography. The chromatographic separation utilises Spherisorb amino columns (five micron) packed in our laboratory. Quantification is achieved by direct comparison with aqueous standards. The oligosaccharide composition of ten lupinseed varieties, from four species, are reported and the values obtained compared with those found for soy beans. The contents of stachyose and verbascose, which are considered to be of major importance as flatus factors, are found to be similar to those in soy beans for some lupinseed species (L. albus and L. angustifolius) but considerably higher in others (L. luteus and L. mutabilis).