Showing papers by "University of Warwick published in 1974"

The Water Balance

Abstract: The ultimate source of water for plants is precipitation; rain falling upon soil penetrates it at a rate depending upon the physical properties of that particular soil; snow and hail do the same after melting. If the rate of rainfall or the rate of production of water by melting exceeds the infiltration rate, then surface runoff occurs and the excess water drains into streams and eventually reaches the sea. That water which penetrates the soil replenishes the soil reservoir and when this is filled to capacity (see chapter 3) the surplus drains through into the aquifers. These are strata such as sand or chalk which can hold substantial quantities of recoverable water. Water held in the soil reservoir is drawn into plant roots and up their stems to be evaporated from the leaves back into the atmosphere, where it rejoins water evaporated from the sea, lakes and rivers and from the surface of wet soil. This so-called hydrological cycle (figure 1.2) depends for its continuance upon energy derived from the sun’s radiation and as will be shown in later chapters its rate is governed largely by meteorological factors.

Popper’s qualitative theory of verisimilitude

Abstract: MILLER, D. [1974]: 'Popper's Qualitative Theory of Verisimilitude' British fournalfor the Philosophy of Science, 25, pp. 166-177. POPPER, K. R. [1963]: Conjectures and Refutations. POPPER, K. R. [1966]: 'A Theorem on Truth-Content' in P. Feyerabend and G. Maxwell (eds.): Mind, Matter and Method, Essays in Philosophy and Science in Honor of Herbert Feigl, pp. 343-53. POPPER, K. R. [1972]: Objective Knowledge. TICHe, P. [1974]: 'On Popper's Definitions of Verisimilitude', British Journal for the Philosophy of Science, 25, pp. 155-160.

On the modular representations of the general linear and symmetric groups

Abstract: Let V be an n-dimensional vector space over C with basis X 1, X 2,..., X n and let T r = V ⊗ V ⊗ ... ⊗ V (r factors). T r is a module both for GL n (C), via its action on V, and for the symmetric group S r by place permutations.

Effect of multiple scattering on experimental Compton profiles: a Monte Carlo calculation

Abstract: A Monte Carlo technique is used to calculate the total intensity and spectral distribution of multiple scattered photons in a typical γ-ray Compton scattering experiment. The method can be used to correct experimental Compton profiles for the effect of multiple scattering. The procedure is applied to two profiles of water measured on samples of different thicknesses and the resultant corrected profiles are seen to be independent of the original sample thickness; furthermore their agreement with a recent calculation using a near Hartree-Fock wave function is significantly improved.

Legislation, Ideology and Economy in Post-1948 South Africa

Abstract: (1974). Legislation, ideology and economy in post‐1948 South Africa. Journal of Southern African Studies: Vol. 1, No. 1, pp. 5-35.

Distribution of self-incompatibility alleles and breeding structure of open-pollinated cultivars of Brussels sprouts

Abstract: Distribution of self-incompatibility alleles and breeding structure of open-pollinated cultivars of Brussels sprouts

The microstructures of silicon nitride ceramics during hot-pressing transformations

Abstract: The microstructure of silicon nitride hot-pressed with a magnesium oxide additive has been studied by transmission electron microscopy. This includes material at various stages in a hot-pressing process: the initial (∼ 90%α) silicon nitride powder; specimens partially densified and partially transformed from α-silicon “nitride” (Si11.5N15O0.5) to β-silicon nitride (Si3N4); and almost fully dense and fully transformed β-Si3N4. The observations substantiate a solid/liquid/solid transformation mechanism, whereby Si and N are transported from α grains through a silicate liquid phase to nucleation sites for β at α/liquid interfaces or to β grains nucleated homogeneously in the liquid phase.

Studies on energy-linked reactions: modified mitochondrial ATPase of oligomycin-resistant mutants of Saccharomyces cerevisiae.

Abstract: Oligomycin resistance is expressed at the mitochondrial and submitochondrial levels in oligomycin-resistant mutants of Saccharomyces cerevisiae. Studies of the mitochondrial ATPase and Pi-ATP exchange reaction indicate that a modification of the mitochondrial ATPase (ATP-synthetase) complex is involved. The specific resistance at the mitochondrial level to oligomycin and related inhibitors such as ossamycin, rutamycin and peliomycin and the lack of resistance to other inhibitors of mitochondrial ATP synthetase (triethyltin sulphate, venturicidin, aurovertin, Dio-9) correlate with whole cell studies and provide further evidence for a specific modification of an inhibitor site on the mitochondrial inner membrane. Mitochondrial mutants which map at the OLI and OLII loci can be differentiated biochemically by their sensitivity to oligomycin of mitochondrial ATPase and the pH 9.5/pH 6.5 ATPase activity ratios. Studies utilising F1-ATPase from wild type and oligomycin-resistant mutants indicate that oligomycin resistance is due to a modification of a membrane-bound component of the mitochondrial ATP-synthetase complex and not to a modification of F1-ATPase or the oligomycin-sensitivity-conferring protein. Partially purified oligomycin-sensitive ATPase preparations (Triton X-100 extracts) retain the sensitivity (resistance) and specificity of the original membrane-bound system in mitochondria. Purified oligomycin-sensitive ATPase preparations also retain the specificity of the original membrane preparation but the sensitivity to inhibitors is partially modified. The results support the conclusion that oligomycin resistance is due to modification of mitochondrially coded and mitochondrially synthesised subunits of the oligomycin-sensitive ATPase (ATP synthetase) complex. There is no correlation of oligomycin resistance with the ergosterol concentration of yeast cells, yeast mitochondria or mitochondrial ATPase.

Walking around the Brauer tree

Abstract: LetG be a finite group, and k a field of finite characteristic p, such that the polynomial x¦G¦ –1 splits completely in k[x]. Let Β be a kG-block which has defect group D which is cylclic of order pd (d ≧ 1). Brauer showed in a famous paper [2] that, in case d = 1, the decomposition matrix of Β is determined by a certain positive integer e which divides p − 1, and a tree Г, a connected acyclic linear graph of e + 1 vertices and e edges. Twenty-five years later Dade ([3]) extended Brauer's theorem to the general case.

Evaluating the friction of distance parameter in gravity models

Abstract: Cliff A. D., Martin R. L. and Ord J. K. (1974) Evaluating the friction of distance parameter in gravity models, Reg. Studies 8, 281–286. In this paper we consider whether map pattern (spatial autoc...

Price, quality, and selling time in the housing market

Abstract: (1974). Price, quality, and selling time in the housing market. Applied Economics: Vol. 6, No. 3, pp. 171-187.

MoO3 layers — optical properties, colour centres, and holographic recording

Abstract: The spectral variations of optical absorption and refractive index are reported for thin layers of molybdenum trioxide prepared by evaporation in vacuum. These layers can be coloured by ultraviolet light and the absorption spectra of coloured layers show a single broad absorption band centred at 850 nm. The appearance of the colour centre absorption and the associated changes in the intrinsic edge have been used to record stable ‘thin’ holograms. A short discussion is given of the electronic structure of MoO3 and of the defects responsible for coloration. Le spectre d'absorption et l'indice de refraction ont ete mesure pour les couches minces de MoO3. Les couches minces ont ete colorees par UV et le spectre d'absorption des couches minces colorees a une bande d'absorption a la longeur d'onde λ = 850 nm. Le developpement de l'absorption des centres colores et le changement pres de l'absorption fondamentale ont ete utilises pour l'enregistrement holographique.

The Cutting Stock Problem in the Flat Glass Industry

Abstract: The cutting stock problem occurs where large rectangles of some material require cutting into smaller rectangles, in the most appropriate way, to satisfy an order book. A linear programming approach to the problem has been suggested by P. C. Gilmore and R. E. Gomory. An application of this approach in the glass industry is described which is shown to be inadequate since it only satisfies a wastage criterion. In practice, multiple criteria must be satisfied and two alternative approaches using linear programming and heuristic scheduling are proposed.

Some factors affecting the efficiency of water‐traps for capturing cabbage root flies

Abstract: SUMMARY Several factors influencing the efficiency of water-traps in capturing cabbage root flies were studied at Wellesbourne in 1971 and 1972. In both the laboratory and field, approximately twice as many flies were caught in fluorescent as in non-fluorescent yellow traps. Depending upon trap density, addition of a source of the attractant allylisothiocyanate (ANCS) increased the numbers of females captured by approximately twofold in fluorescent traps and from two- to sevenfold in non-fluorescent traps. Traps were equally efficient irrespective of whether the ANCS was renewed every 2, 3, 4 or 5 days. On the first day of trapping, the number of flies caught per unit area was linearly related to the square root of the number of traps in that area. On the following days the rate was probably in equilibrium with the combined effect of immigration and the rate of development of responsive flies in the trapping zone. Most males were caught 30 cm above the soil surface and most females at soil level. Traps 120 cm above the soil surface caught few flies. Populations of marked flies were released into large field cages containing both a section of hedgerow and a plot of cauliflowers. Even after a week, only 81 % of the males and 55 % of the females had been recaptured from the most responsive of these captive populations. Furthermore, only 30 % of females were recaptured when they were more than 8 days old, the age at which most probably enter the new host-crop.

Hardness anisotropy in niobium carbide

Abstract: Measurements of hardness anisotropy by Knoop diamond indentation on the {100} surfaces of Nb6C5 crystals show that the hardness is determined by crystallographic slip on {111} 〈1¯10〉 and {110} 〈1¯10〉 systems. {111} is the preferred slip plane for Nb6C5 and crystals with higher carbon content which show a marked decrease in Knoop hardness. The carbon atom/vacancy arrangement in these crystals is shown, by electron diffraction, to possess short-range order. Crystals annealed at low temperatures contain domains of non-cubic long-range order which increase the Knoop hardness and eliminate the anisotropy in hardness. Dislocation arrangements around Knoop indentations have been directly observed by electron microscopy in an attempt to confirm the slip processes deduced from hardness anisotropy.

The sowing of germinating vegetable seeds using a fluid drill

Abstract: SUMMARY Carrot seeds which had been imbibed or germinated and were then sown in a gel extruded through standard coulters emerged five days earlier than dry seeds sown with a conventional drill and gave higher yields after 64 days although not after 77 days. There was no difference in mean time to emergence or in final plant stand between lettuces grown from dry seeds and those from seeds imbibed for 24 h and sown in a gel, but the duration of the emergence period of the latter was halved in one of the two experiments. Celery seeds, the light requirements of which had been satisfied during germination in optimum conditions in the laboratory before they were sown in the field in a gel, gave a 60% plant stand as compared with a stand of 2% from dry seeds.

The health service consumer: a sociological misconception

Abstract: I T has become fashionable in the last decade to speak of patients as health service consumers, a fashion to which I have succumbed (Stacey 1974). More careful analysis suggests, however, that the term 'consumer' is of limited value in understanding the status and role of the patient\"; that it is an economic term which implies a theoretical model of the health service which is quite inappropriate and which conceals as much as it illuminates. Deriving from economics it has now become a social actor's termand is a political term, in the sense that it has been used by certain social actors to legitimate alterations in the power structure. 'Health service consumer' is inappropriate terminology to describe a sociological conception of the patient. An analysis of the 'Dilemmas of participation: the case of the health service consumer' (Stacey, forthcoming) led me to this conclusion, the case for which I now wish to argue more directly. The notion of a patient as a consumer has arisen, it seems, from two sources. The first is the application of an economic industrial model to the health service; the second is from the consumer movement. The term is therefore located in two distinct developments, both with specific historical referrents. The nub of my argument is that the health service can better be seen as a process of continuing interaction between patient and health care professionals and workers than as an industry or other predominantly economic activity. There is a sense in which the health service is an economic enterprise of course. The N.H.S. is the largest British employer and only Shell and B.P. have a larger turnover.\" Not only is the health service much more than economic enterprise, in so far as one does think of the health service as an industry, a patient can be said to be a producer as much as a consumer of that elusive and abstract good: health.

Investigations into the cytokinin-like properties of benzimidazole -derived fungicides

Abstract: SUMMARY Of seven systemic benzimidazole fungicides tested, four showed cytokinin activity in a modified Amaranthus betacyanin bioassay. In the presence of the gibberellins A4 and A7, in the dark at 25°C, the four active compounds stimulated the germination of seeds of two celery cultivars dependent on cytokinin for germination under these conditions. One cytokinin-active fungicide was methyl benzimidazol-2-yl carbamate (MBC) and the other three break down into this compound in solution. The three inactive fungicides do not. However, the hormonal properties of the cytokinin-active fungicides may not be due to the MBC moiety alone because sometimes they were more cytokinin-active than pure MBC.

The identification of a grain-boundary phase in hot-pressed silicon nitride by Auger electron spectroscopy

Abstract: The presence of magnesium, calcium and oxygen has been detected in the intergranular fracture surface of an Si3N4-7% MgO hot-pressed material by Auger electron spectroscopy, together with a chemical shift in the silicon Auger peak. The composition of this grain-boundary phase has been estimated as (0.40 ± 0.03) CaO. (0.75 ± 0.10) MgO. 2SiO2 by comparison with spectra obtained from a bulk glass specimen of similar composition. The reduction in strength of the hot-pressed material at temperatures above 1000° C has been attributed to the decrease in viscosity of this phase.

Fixation of Dinitrogen by Free-Living Microorganisms

Abstract: The purpose of this article is not to review exhaustively all that is known about nitrogen-fixing microbes but to provide a reasonable coverage of more recent discoveries in the field. It is primarily concerned with the microbiology of the free-living nitrogen-fixing organisms, although casual reference to symbiotic systems has been made. With this in mind, I shall attempt not to burden the reader with microbiological minutiae but will restrict coverage to those biological aspects which help us understand how such a diverse assortment of microbes can grow with N2 gas as their sole nitrogen source. The discovery of the nitrogen-fixing character in a certain microorganism sometimes necessitates a reevaluation of its taxonomic position. Where necessary, this has been done.