Showing papers by "Lancaster University published in 1975"

A Communicative Grammar of English

Abstract: Part One: A guide to the use of this book (Sections 1-56) Part Two: Grammar in use (Sections 57-434) Section A: Concepts Section B: Information, reality and belief Section C: Mood, emotion, attitude Section D: Meanings in connected discourse Part Three: A-Z in English grammar (Sections 435-747)

Photometric observations of Mercury from Mariner 10

Abstract: The elimination of the residual image problem which plagued previous Mariner imaging systems allowed photometry of moderately high quality to be carried out on Mercury by Mariner 10. The conclusions from the photometric analysis are as follows. To a surface resolution of 20 km, Mercury is covered with a dark fine-grained soil similar to the lunar regolith. No regions having anomalous polarization or color were discovered, which might have implied large amounts of metallic Fe or exposed bare rock. Photoclinometry suggests that the center of the Caloris Basin may be about 9 km below the outside rim. The heavily cratered plains have albedos of about 0.17, somewhat brighter than the lunar highlands. The albedos of the darker smooth plains and the interiors of bright fresh craters are systematically higher than their lunar counterparts. One consistent interpretation of the color and albedo relationships is that the dark smooth plains resemble the low-Ti, low-Fe lunar maria and that the crust is generally low in Ti, metallic Fe, and Fe(3+).

The effect of calcium on gill potentials and on sodium and chloride fluxes in the goldfish,Carassius auratus

Abstract: Measurements of electric potential and of sodium and chloride effluxes were carried out on a freshwater fish, the goldfishCarassius auratus. The potential was affected by a number of inorganic ion species but that with the most significant influence on transepithelial potential was calcium. The potential was about 10 mV negative in the absence of calcium and about 10 mV positive in the presence of 10 mM/l calcium. Sodium and chloride efflux rates were greatly reduced upon the addition of calcium to the medium. The origin of the transepithelial potential is discussed in terms of the relative permeability of the branchial membranes to sodium and chloride and the factors influencing these permeabilities.

Stratigraphy and geology of the ignimbrites of Vulsini Volcano, central Italy

Abstract: Vulsini Volcano, Bolsena District, central Italy is a Quaternary centre eruptions of which have been dominated by the production of ignimbrites. Stratigraphic studies show that there are six major ignimbrite units with individual minimum volumes of 0.5 to 3 km3 and a large number of smaller ignimbrite units, together with pyroclastic surge and pyroclastic fall deposits. It is estimated that at least 90% of the volcanic products are pyroclastic producing a low profile volcano with 1 to 5‡ slopes.

Some Comments on the Combination of Forecasts

Abstract: This paper examines some of the theoretical implications of combining forecasts using a minimum variance criterion. In particular, the derivation of the exact expression for the minimum variance weight vector is provided, together with a proof that the error variance of the composite forecast is no greater than that of any of the component forecasts. A detailed examination is made of the probability distributions of the weight estimators, and an explanation is given for the occurrence of negative weights.

The Innervation of Muscle

Abstract: This chapter discusses the details concerning the innervation of the various invertebrate skeletal muscles and the responses produced by their efferent axons. There are two basic ways in which muscle fibers are activated by impulses from the central nervous system. One method involves the production of a propagated action potential that arises at one point on the muscle fiber surface; this action potential passing rapidly to all regions of the fiber to activate the contractile system. The second method involves the production of large numbers of non-propagated action potentials or graded depolarizations that arise at a number of points along the muscle fiber. As these membrane disturbances occur simultaneously at all points, they synchronize the activation of the contractile machinery of the whole fiber. The former method is found in vertebrate skeletal muscles, while the latter is found in most invertebrates and particularly in the arthropods. The vertebrates and invertebrates, thus, differ in that the former have focal innervation with the exception of the intrafusal muscle fibers of the muscle spindle proprioceptor and the tonic fibers of amphibia, birds, and mammals, while the latter have multiterminal innervation.

Personality similarity and friendship choices by adolescents

Abstract: In a study designed to examine the nature of the relationship between personality similarity and established friendships amongst adolescents, three groups of frequently interacting subjects of different ages were given Reptests (Kelly, 1955) as a means of eliciting the content of their personal construct systems. In all three groups (early-, mid- and late-adolescence), pairs of friends were found to have more similar constructs than nominal pairs of group members. However, there were age-related differences in the kinds of construct on which the similarity was most significant (for example, similarity on constructs relating to factual description predicted friendship choices in early adolescence but failed to do so in later adolescence, where similarity of constructs concerning physical attributes was a relevant factor). Sex-differences in the functional basis of friendship were also found, with mid- and late-adolescent girls' friendship choices correlating with similarity of psychological description. Temporal and sex differences in the basis of friendship suggest that the concept of ‘friendship’ must be seen as more differentiated and less unitary a concept. Adolescent friendship illuminates several dimensions along which this differentiation assumes both theoretical importance and functional relevance.

The fine structure of the epidermis of two species of salmonid fish, the Atlantic salmon (Salmo salar L.) and the brown trout (Salmo trutta L.)

Abstract: The fine structure of the epidermis of two species of salmonid fish has been described. Gross characteristics have been noted along with many apparent differences in the epidermis of different body regions of the fish. The major cell type is the filamentcontaining cell and this has been described in detail. The major inclusions of the cell are the tonofilaments. Differences in basal, mid-epidermal and peripheral filament-containing cells have been characterised. Comparisons of fish epidermis with that of other vertebrates has been made.

The climatic control of the altitudinal distribution of sedum rose a (l.) scop. and s. telephium l.

Abstract: SUMMARY When plants of Sedum rosea (L.) Scop, and S. telephium L. ssp. fabaria Syme are grown in competition at different altitudes it is found that the growth of the species is affected differentially. This effect is such that at low altitudes S. telephium is a larger plant than S. rosea, while the reverse is the case at high altitudes. The observed differences are caused by a marked sensitivity of the growth of S. telephium to differences in altitude, while S. rosea is very insensitive. The most probable cause of these responses would appear to be differences of climate. The influence of altitude in northern England on air temperature, saturation deficit and irradiance has been investigated in order to establish the magnitude of the differences which may cause these responses.

The effect of leaf age on leaf resistance and CO2 exchange of the CAM plant Bryophyllum fedtschenkoi.

Abstract: Leaves of different ages from the CAM (Crassulacean acid metabolism) plant Bryophyllum fedtschenkoi Hamet et Per. differ in their ability to accumulate titratable actidity during the night. Measurements of leaf resistance to water vapour diffusion and net CO2 exchange during the day and night show differing patterns of behaviour dependent upon leaf age. Young leaves do not exhibit CAM; they behave like typical mesophytes with low resistances and a net uptake of CO2 during the day and a net output of CO2 at night. Mature leaves exhibit CAM and have high leaf resistances during the day and lower resistances at night but their pattern of CO2 exchange is complex, with a net output early in their day followed by a net uptake which continues at a reduced rate through the night. Intermediate, leaves are intermediate in their behaviour The presence of CAM in older leaves may simply be the result of increased cell vacuole size.

Changes in cellular composition during magnesium deficiency.

Abstract: Mg deficiency increased the water content of the liver, kidney, heart and thigh muscle in the rat and decreased the proportion of nitrogen in the dry matter of the same tissues. Changes in the concentration of metals also occurred. 2. Cellular fractional indicated that the Mg and K depleted in liver occurred primarily in the heavy-mitochondrial and microsomal fractions respectively. The calcification of liver and kidney was due to preferential deposition of Ca in the heavy-mitochondrial fraction. 3. The proportion of cellular nitrogen present in the heavy-mitochondrial and microsomal fractions was markedly decreased in the liver and kidney of the Mg-deficient rats, and the proportion in the supernatant fraction increased. 4. Electron microscopy revealed that the cross-sectional areas of liver cells and all their mitochondria were decreased in Mg deficiency. The number of mitochondrial per cell was decreased even more severely and the average area of a mitochondrion was greater in deficient rats than in control animals. 5. The significance of these observations is discussed in relation to the location of the primary metabolic disturbance during Mg deficiency.

Utilization of Transferability in Molecular Orbital Theory

Abstract: Publisher Summary This chapter discusses the utilization of transferability in molecular orbital theory. The chapter elaborates on the ways in which transferability can be utilized in the construction of wavefunctions for large systems. The chapter explores those methods that use such transferability to mimic ab initio calculations on large molecules, and the role played by transference in improving the numerical convergence of self-consistent field (SCF) cycling procedures. Within the molecular orbital theory, the transference of matrix elements from one molecule to another and their possible use in the construction of wavefunctions for large systems forms a natural alternative to the transferability of the parts of a wavefunction, such as localized orbitals. The chapter discusses various methods involving the transfer of matrix elements that includes the Non EmpiricaI Molecular Orbital (NEMO) scheme, and Simulated Ab initio Molecular Orbital (SAMO) scheme. The chapter presents the transference methods involving the use of localized orbitals, and finally considers the use of both transferred matrix elements and transferred localized orbitals in improving the efficiency of SCF cycling procedures.

Complex Demodulation of Geomagnetic Data and the Estimation of Transfer Functions

Abstract: Summary Complex demodulation is a technique that allows the examination of the variation with time of the amplitude and phase of selected frequency components of a time series. Complex demodulates can form the basis for estimates of the power spectrum of the time series. They are computed most efficiently by the use of the Fast Fourier Transform. Two examples of the application of complex demodulation to the analysis of geomagnetic time series are given. In the first example, the technique is used to demonstrate the modulation of a periodic phenomenon, the daily variation, by mechanisms with apparent periods of 6 months and 27 days. The second example, discussed in greater detail, is an application to the calculation of Geomagnetic Deep Sounding transfer functions. The spectra of simultaneous records of variations in the three components (H, D and Z) of the magnetic field recorded at a single station are divided into bands, and each band demodulated in turn. The polarization azimuth of the horizontal field at each instant of time can be computed, and, for the example considered, the azimuth tends to be constrained to the north-south direction. The detailed response of the local conductive structure to different source field polarizations can be demonstrated. Everett & Hyndman's Unit Vector Method is used to investigate the effect of the observed bias in the azimuth of the source field on estimates of GDS transfer functions made by conventional methods. The demodulates can be used to devise criteria for selecting events according to their signal/noise ratio. The selection procedure is most useful when applied to records containing only sporadic activity in the frequency band of interest.

Natural regeneration of tilia cordata in relation to forest-structure in the forest of bialowieza, poland

Abstract: The history of the forest of Bialowieza is briefly reviewed. The National Park was created in 1923 in the central and apparently least exploited part of the forest. The composition of the forest varies in relation to the nature of the soils. Almost half of the wooded area of the park is occupied by forest composed of Carpinus betulus, Tilia cordata, Quercus robur, Acer platanoides, Ulmus glabra and Picea abies (Querceto-Carpinetum). The structure of this association is illustrated by maps and transects of selected plots. An almost continuous canopy is formed by Carpinus betulus with tall emergent trees of Tilia cordata, Quercus robur and Picea abies. Tilia cordata regenerates freely and there are numerous groups of seedlings, saplings and young trees which are sometimes in gaps but often beneath the main canopy. The origin of the groups is analysed and evidence is presented that those of T. cordata are probably always less than 50 years old. This is in contrast to analyses made by Paczoski (1928a, b, 1930) shortly after the park was established, when trees of T. cordata with trunk diameters less than 0.3-0.4 m were absent. There is now a discontinuity in the distribution of diameter classes in the population. The influence of this change on the structure of the forest is discussed.

Optical detection of Fe 3+ in lunar plagioclase

Abstract: NATURAL plagioclase from terrestrial sources exhibits a cathodal luminescence spectrum which consists in general of three emission bands1,2. The emission band in the blue region of the spectrum is thought to be associated with lattice defects2, but the other emission bands are caused by transition-metal impurities present in concentrations of the order of 100–1,000 p.p.m. In particular, the emission band centred at 560 nm has been ascribed to Mn2+ ions substituting in Ca2+ sites, and the emission band on the edge of the infrared has been shown to be caused by Fe3+ ions probably in tetrahedral Al3+ sites3. The relative intensities of these emission bands vary from sample to sample, but the Fe3+ emission is often dominant in natural terrestrial plagioclases. These conclusions, concerning the nature of the luminescence centres involved, were arrived at by studying the emission characteristics of selectively activated, high purity, synthetic plagioclases3. Optical measurements presented there show that, using excitation spectroscopy, the detection of Fe3+ is possible in the plagioclase fraction of lunar fines.

Changes in CO2 and water vapour exchange rates in leaves of Quercus robur infected by Microsphaera alphitoides (powdery mildew)

Abstract: Infra-red gas analysis techniques were used to follow CO 2 exchange in leaves of Quercus robur L. seedlings infected with Microsphaera alphitoides Griffon and Maublanc. Infected leaves showed an initial increase in net photosynthesis, followed by a rapid decline, to levels significantly lower than those of control leaves on the second day after inoculation. Photorespiration rates in infected leaves were reduced throughout the 7 day experimental period. Dark respiration increased to a peak 5 days after inoculation which was followed by a period of decline. Overall respiration (photorespiration and dark respiration) was found to decrease from the time of inoculation. The decrease in photorespiration was responsible for the transient increase in net photosynthesis that occurred soon after infection. Transpiration rates in infected material increased within 2 to 3 days after infection and the difference between healthy and infected tissue was greatest in the dark. No effect of mildew on stomatal movements was observed until the sixth day, when there was a reduction in the aperture of stomata in the light. The greater part of the increased transpiration in infected material took place via the mycelium. The relative turgidity and water potential of infected leaves were reduced from the fourth day after inoculation although the decreases were probably not responsible for the reduction in photosynthetic rate. Some solute loss from infected tissue was indicated on the sixth day. It was concluded that the reduction in the net photosynthetic rate of diseased leaves was due to biochemical changes other than those directly related to a change in the water status of the tissue.

A typology of teaching styles in primary schools

Abstract: Summary. Differences in teaching styles have conventionally been described in terms of ill-defined dichotomies. The aim of the present study was to provide a more adequate representation of teaching practices by creating a typology based on the self-reported strategies of primary school teachers. 1,258 third and fourth year teachers completed a questionnaire, and the resultant information was cluster analysed. Twelve teaching styles were extracted. Although the usual poles of informal and formal styles were apparent, most teachers appeared to adopt intermediate styles, incorporating elements of both informal and formal strategies. Evidence regarding the validity of the clusters is presented.

Fine-structural observations on Papposphaera Tangen from the Southern Hemisphere and on Pappomonas gen. nov. from South Africa and Greenland

Abstract: The presence of Pappomonas lepida Tangen is demonstrated in South Africa for the first time and its coccoliths shown to be more scale-like at the base than has previously been recognised. Somewhat similar but differently arranged appendages are used as the basis for a new genus Pappomonas, well represented in South Africa but also present in West Greenland. The type species P. flabellifera sp. nov. is described and illustrated with special reference to the protoplasmic appendages and aspects of coccolith structure in both calcified and uncalcified specimens. Some preliminary conclusions on coccolith morphology are outlined but more detailed discussion is deferred until a second species of Pappomonas, so far known only from West Greenland, has been described.

Increased transpiration and the accumulation of root absorbed 86Rb in barley leaves infected by Rhynchosporium secalis (leaf blotch)

Abstract: Infection of barley leaves by Rhynchosporium secalis (Oudem.) J.J. Davis (leaf blotch) caused increased transpiration from the infected area in the light and in darkness. The increase is attributed to the increase in mean stomatal aperture in the infected area, reported previously [1], and the failure of stomata at the infection site to close in the dark, found here. Failure of stomata to close in the dark prevented measurement of the contribution of cuticular transpiration to the increase in total transpiration, but indirect evidence suggests that it was small until the late stages of infection when sporulation commenced. The increase in transpiration was greater and occurred sooner in a susceptible host variety than in a resistant variety. More root absorbed 86Rb accumulated in the infected region of leaves than in other regions of the same leaves, or in any region of healthy leaves and, as with transpiration, the difference between healthy and infected regions was greater in the dark than in the light. Accumulation in all regions was reduced by factors that reduce transpiration, such as darkness or a saturated atmosphere. After the roots had been transferred to distilled water 86Rb continued to accumulate in all regions of infected leaves. The possible existence of factors, in addition to transpiration, that influence solute accumulation in diseased plants is discussed.

A study of communication behaviour in an R & D laboratory

Abstract: There is still much uncertainty about the determinants of technical communication flow in UK R & D laboratories and even more uncertainty about the causal link between communication behaviour and performance. Hence it is not clear what managerial action should be taken to improve technical communication flow and what effect such action would have on research productivity. In this study the main factors influencing communication flow are identified and the role of basic human characteristics in determining both communication behaviour and performance are studied and discussed.

Diffusion of stabilizers in polymers. I. 2,4‐dihydroxybenzophenone in polyolefins

Abstract: The diffusion of the ultraviolet stabilizer 2,4-dihydroxybenzophenone in compressionmolded sheets of low-density polyethylene, high-density polyethylene, and isotactic polypropylene was investigated over the temperature range of 44–75°C. The magnitude of the diffusion coefficients for these polyolefins was found to decrease in the order low-density polyethylene > high-density polyethylene > polypropylene, the corresponding activation energies being approximately 18, 23, and 34 kcal/mole. Studies under conditions of saturation indicated that the migration of this stabilizer was confined to the more accessible amorphous regions of the polymers. The rate of loss of stabilizer from polymer samples immersed in water was also investigated at 44°C. Values of the diffusion coefficients calculated from the results of these studies were somewhat greater than those determined from the diffusion studies for the low-density polyethylene and isotactic polypropylene samples and considerably smaller in the case of high-density polyethylene. The extraction studies also permitted the quantitative evaluation of the solubilities of the stabilizer in the polymers. These were found to be 0.003, 0.03, and 0.07 wt-% for high-density polyethylene, low-density polyethylene, and polypropylene, respectively, at 44°C.