Showing papers by "University of Reading published in 1974"

Linguistic Change and Diffusion: Description and Explanation in Sociolinguistic Dialect Geography.

Abstract: Linguistic geography has remained relatively unaffected by recent developments in sociolinguistic theory and method and theoretical geography. In this paper it is argued that insights and techniques from both these disciplines will be of value in improving descriptions of geographical variation in language, and that these improvements will in turn lead to more adequate explanations for certain of the social and spatial characteristics of linguistic change. Evidence in favour of a sociolinguistic methodology and new cartographic techniques in dialect geography is drawn from empirical studies in urban dialectology, in East Anglia, England, and rural dialectology, in Norway. (Sociolinguistic variation, dialectology, linguistic change, British English, Norwegian.)

Atmospheric halocarbons and stratospheric ozone

Abstract: ODD chlorine1 is a more potent catalyst for the destruction of ozone than is odd nitrogen2. Molina and Rowland3 warn that chlorine released during the photochemical destruction of fluorocarbons (FCCs) constitutes a potentially serious threat to the integrity of the stratospheric ozone layer.

A three-dimensional primitive equation model of cumulonimbus convection

Abstract: The model is described and the results of three integrations presented. Its main novel features are the inclusion of non-hydrostatic terms in a pressure co-ordinate system, and the treatment of flow through the lateral boundaries. The results of the integrations, one with an ambient vertical wind shear and two without, indicate that the cloud dynamics is quite sensitive to assumptions made regarding the cloud microphysics, particularly at the stage when the downdraught is produced.

On the phenomenology of chain-extended crystallization in polyethylene

Abstract: The melting and crystallization of polyethylene have been examined in the pressure range 0 to 6 kbar. Volumetric and thermal measurements show that fractionated polymer melts and crystallizes in two clearly resolved stages above 4 kbar. It is suggested that these are due to the formation of a new, high pressure phase of polyethylene with a triple point at ∼ 3 kbar. This phase is intermediate in specific volume and entropy between orthorhombic solid and melt, but closer to the latter, and is either liquid-crystalline or solid. It is shown further that the formation of chain-extended polyethylene correlates with the occurrence of two exothermic processes (unresolved below 4 kbar) during crystallization. This leads to the hypothesis that whereas chain folded crystallization occurs by direct transformation from melt to orthorhombic solid, chain-extended polyethylene results when the intermediate phase intervenes in crystallization. This hypothesis appears capable of accounting for most of the known f...

Two-dimensional particle models in semiconductor-device analysis

Abstract: A microscopic-scattering particle model is described that combines a 2-dimensional spatial representation of the fields with a 2-band Monte Carlo description of the scattering events. A simplified scattering law produces a particle model for the diffusion approximation. Results are shown for Si and GaAs f.e.t.s and a GaAs diode.

Problems in the elementary analysis of standard biological materials

Abstract: Les milieux biologiques etalon pour une analyse elementaire sont peu nombreux et posent des problemes d'homogeneite, de conditions reproductibles, de sechage et de stokage. Leur usage a souleve un certain nombre de problemes concernant la surete de certaines techniques analytiques, quelques uns de ces problemes n'ont toujours pas de solution. Ils sont illustres en se referant a un echantillon standard de chou, de sang humain, d'hematies et de serum, lesquels ont ete analyses a plusieurs reprises. Des valeurs raisonnablement sures sont maintenant connues pour les 35 elements suivants dans l'echantillon standard de chou: Al, As, Au, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, Hg, K, La, Mg, Mn, Mo, N, Na, P, Pb, Rb, S, Sb, Sc, Si, Sn, U, V, W, Zn; il reste des incertitudes pour Ag, Ce, Ga, I, Ir, Ni, Se Sm et Ti. Dans le sang, les analyses des 17 elements suivants sont suffisamment exactes pour permettre l'emploi de ce produit comme un etalon, approximatif. Ba, Br, Ca, Cl, Cu, Fe, I, K, Mg, Na, Ni, P, Pb, Rb, Se et Zn. Cependant il y a de serieux doutes au sujet de la constante de la concentration de certains de ces elements selon les individus. A la suite d'une recente etude, l'exactitude des resultats concernant, Ag, As, Co, Cr, F, Hg et Sb est egalement mise en doute.

Bloom's Taxonomy and the Objectives of Education

Abstract: Summary Bloom's taxonomy, which has been influential in underpinning many of the curriculum developments of the last fifteen years, may be criticized on various grounds. It is a mistake to suppose that Bloom's taxonomy, or any other proposed classification of objectives, can ever be wholly independent of questions of value. On the contrary, it appears that Bloom's taxonomy ‘suits’ the expression of a pragmatic/materialist ethic, and does not particularly suit the expression of ethics either traditionally, or currently, associated with the concept of ‘education’. In implementation Bloom's taxonomy‐‐it is argued‐‐is a disappointingly blunt instrument. This is particularly apparent when we try to use it in the analysis of mathematics in the upper school. In history the taxonomy seems to lead to conclusions which invert both commonsense and the judgement of experienced teachers. The major criticism of Bloom's taxonomy which is advanced in this paper∗ is, however, that the taxonomy omits a vital ingredient in ...

Case alternation impairs word identification

Abstract: Smith (1969) and Smith, Lott, & Cronnell (1969) claimed that word identification was not impaired by printing the characters making up a word in a mixture of cases. If this were so, it would rule out such word-identification models as the “more-features” model of Wheeler (1970) and Rumelhart & Siple (1972). The experimental methods used by Smith et al are criticized. A straightforward word-identification experiment revealed that case alternation does, in fact, lead to a large impairment of word identification, as would be predicted by models of word identification based on multiletter visual features.

Effects of photoperiod, temperature and vernalization on the phenology and spikelet numbers of spring wheats

Abstract: SUMMARY Fourteen cultivars of north temperate, Australian, Mexican and Rhodesian origins, were grown in eight treatments: 2-day-lengths (10 h and 14h) × two temperature regimes (18/13 °C and 25/20 °C) × two seed vernalization treatments (unvernalized and 28 days at 1–2 °C). Numbers of days to 50 % ear emergence, leaf numbers and spikelet numbers of the main shoots were recorded. The north temperate cultivars were the most sensitive to daylength: in long days their mean spikelet number was 15 and they headed in 40–50 days, while in short days they had a mean of 24 spikelets and failed to head in 100 days. The Rhodesian cultivars were the least sensitive, but nevertheless headed 20–30 days earlier and had three to five fewer spikelets per ear in long days. The effects of vernalization on the tropical cultivars were related to maturity class: they ranged from negligible in early cultivars such as Sonora 64 and Devuli to decreases of 20 days to heading and seven spikelets in late cultivars such as Mexico 120 and Cajeme 71 in long days. The effects of temperature varied with cultivar and with vernalization treatment. Early cultivars and vernalized late cultivars headed earlier and had fewer spikelets in the warmer regimes while unvernalized late cultivars tended to have more spikelets and headed later. It is suggested that some vernalization of these late cultivars took place in the cooler regime. The significance of the results for the understanding of the physiological basis of the adaptation of wheat cultivars to different climatic zones is discussed.

Further Observations on the Toxicity of Navy Beans (Phaseolus vulgaris) for Japanese Quail (Coturnix coturnix japonica)

Abstract: Summary. The lethal and growth depressing effects of feeding raw navy beans (RNB) to Japanese quail have been shown to be due neither to poor palatability nor to dialysable, lipid or carbohydrate constituents, but to a protein material soluble at pH 3 and precipitable by saturation with (NH4)2SO4. This material proved resistant to digestion by pepsin and proteolytic bacteria but was destroyed by autoclaving at 121° for 15 min. Germfree birds given a diet containing RNB which had been fermented by coliforms grew well, indicating that toxicity of RNB is not dependent on the release by intestinal bacteria of poisons from innocuous precursors in the beans. Examination of the effects of feeding diets containing other raw legume seeds to quail have shown that toxicity is associated with the presence of high concentrations of phytohaemagglutinins (PHAs). Quail given RNB diet showed a greater incidence of liver infection than birds fed an autoclaved bean diet but bacteriological examination of gut contents of such birds revealed no marked qualitative or quantitative differences. Chemical examination of gut contents likewise revealed no marked differences. Experiments with gnotobiotic quail showed that coliforms derived from a variety of sources were capable of causing the death of birds on RNB diet and that the numbers attained in different parts of the intestine by a single coliform strain were not affected by the diet fed. The results suggest that toxicity of RNB may be due to impairment of body defence mechanisms by PHA leading to tissue invasion by normally innocuous components of the intestinal microflora.

The lipids of the alga Spirulina

Abstract: The blue-green alga, Spirulina maxima, examined in the form of a spray-dried powder, contains 11% of lipid, which has been analysed in detail with a view to establishing both the classes of lipid present and their fatty acid profiles. The dominant lipids are mono-, di- and probably higher galactosyldiglycerides and phosphatidyl glycerol. Unlike other algae, Spirulina synthesises cis-6-cis-9-cis-12 octadecatrienoic acid in contrast to its 9–12–15 isomer.

Agricultural policies in developed countries: a review*

Abstract: The article attempts to survey the recent contributions by economists to the analysis of agricultural policies in developed countries, and to take stock of the state of our knowledge of the extent to which these policies have been successful. It is restricted to readily available contributions in the English language and concentrates on the evaluation of price and factor market policies. A broad consensus has emerged, based on a neoclassical analysis of the performance of a competitive industry, as to the nature of the problems of the agricultural industry. This consensus is preserved in the interpretation of the implications of government intervention, and the difficulties that emerge when policies are designed which attempt to alter long run resource returns. Economists have employed a variety of approaches to policy analysis, depending in part on the weight that they give to institutional factors. The economic tools which have been used in policy analysis have demonstrated the need to specify the aims of policy or the underlying social criteria, and generalisations as to the relative efficiency of alternative instruments are not easy to find. An examination of the interaction among general economic and specifically agricultural policies identifies a number of areas where there is insufficient evidence and points to a change in the emphasis which a period of inflation has brought about. Resume POLITIQUES AGRICOLES DANS LES PAYS DEVELOPPES: UN TABLEAU Cet article entend dormer un apercu d'ensemble des travaux recents des economistes portant sur l'analyse des politiques agricoles dans les pays developpes et faire le point de l'etat des connaissances actuelles sur la mesure du succes de ces politiques. Il se limite aux etudes aisement disponibles en lanque anglaise et se concentre sur l'evaluation des politiques afferentes aux prix et au marche des facteurs. Un consensus general est apparu, qui repose sur une analyse neoclassique des resultats d'une industrie competitive, quant a la nature des problemes de l'industrie agricole. Ce consensus reste invariable dans l'interpretation des consequences de l'intervention gouvernementale et des difficultes qui apparaissent lorsque des politiques sont definies qui cherchent a modifier le rendement des ressources a long terme. Pour l'analyse des politiques, les economistes employent des methodes variees, dependant en partie du poids qu'ils attachent aux facteurs institutionnels. Les outils economiques utilises dans l'analyse des politiques ont demontre le besoin de specifier les objectifs de politique ou les criteres sociaux sousjacents, et les generalisations quant a l'efficacite relative des instruments alternatifs ne sont pas faciles a trouver. Un examen de l'action reciproque entre des politiques economiques generales et specifiquement agricoles permet de cerner plusieurs domaines ou les preuves sont insuffisantes et met en lumiere une variation dans l'accent principal suscitee par une periode inflationniste. Zusammenfassung DIE AGRARPOLITIK IN ENTWICKELTEN LANDERN: EINE UBERSICHT Dieser Artikel will einen Uberblick uber Beitrage durch Wirtschaftler in letzter Zeit zur Analyse der Agrarpolitik in den entwickelten Landern verschaffen und ferner Klarheit uber den Stand unserer Kenntnisse mit Hinblick auf das Ausmass des Erfolgs dieser Politik schaffen. Es ist auf leicht verfugbare Beitrage in englischer Sprache beschrankt und konzentriert sich auf die Auswertung von Preis- und Faktormarktpolitik. Eine allgemeine Ubereinstimmung hat sich herausgebildet, die auf einer neoklassischen Analyse der Leistungen einer konkurrenzfahigen Industrie mit Bezug auf die Art der Probleme in der landwirtschaftlichen Branche beruht. Diese Ubereinstimmung wird bei der Auswertung der Folgerungen anlasslich einer Regierungs-intervention und der Schwierigkeiten bewahrt, die durch von der Politik bestimmte Anderungen von langfristigen Ertragen entstehen. Wirtschaftler haben eine Vielzahl von Annaherungen an Politikanalyse versucht, die zum Teil von der Institutionsfaktoren zugeteilten Bedeutung, abhangt. Die wirtschaftlichen Mittel, die bei der Politikanalyse verwendet wurden, haben das Bedurfnis erwiesen, die Ziele der Politik oder die unterliegenden Grundkriterien aufzufuhren, und Verallgemeinerungen bezuglich die entsprechende Wirksamkeit von alternativen Mitteln sind nicht ohne weiteres auffindbar. Eine Untersuchung der Wechselwirkung der allgemeinen Wirtschafts- und insbesondere der Agrarpolitik zeigt eine Anzahl Gebiete auf, wo die Beweise unzureichend sind, was auf eine durch eine Inflations-zeit verursachte Veranderung der Schwerpunkte weist.

On chain-extended and chainfolded crystallization of polyethylene

Abstract: Various polyethylenes have been crystallized from the melt at pressures between 0 and 6 kbar. Their atmospheric melting points fall, in each case, into two non-overlapping regions, with a sharp changeover at a pressure in the region of 3 kbar which is a decreasing function of molecular weight. This separation is used in conjunction with differences in spherulitic texture to distinguish chainfolded polymer (which predominates at lower pressures) from chain-extended polyethylene produced at higher pressures. The thickness of chain-extended lamellae increases with crystallization temperature at a given pressure, with crystallization pressure at a constant super-cooling and with molecular weight (between 2·104 and 5·104) for crystallization at the same temperature and pressure. It is then shown from differential thermal analysis of crystallization as it occurs that chain-folded and chain-extended polyethylene result from two distinct processes and that when both occur at the same pressure and tempera...

The Imposed Norm Hypothesis: A Validation.

Abstract: Previous work suggests that standard dialects assume their prestige over other language varieties not because they are linguistically or aesthetically superior, but because of historical, cultural norms. An empirical investigation lends this view support by showing that British listeners cannot differentiate evaluatively speech styles having distinct social meanings in Greece.

The Meridional Scale of Baroclinic Waves

Abstract: Further numerical and analytical solutions are obtained for unstable disturbances in a two-layer, hydrostatic, quasi-geostrophic model with both vertical and meridional shear in the basic zonal wind, the meridional shear being confined to the upper layer. Contrary to a suggestion of Stone, the meridional scale of the most unstable wave is not, in general, the radius of deformation. As in previous studies, when the meridional scale of the zonal flow is of the order of the radius of deformation, the fastest-growing disturbance is found to take a similar meridional scale. However, for zonal flows of greater meridional extent, numerical solutions show the most unstable wave to have a meridional scale larger than the radius of deformation, although less than that of the zonal flow. In this case the meridional scale of the wave is shown analytically to be given, in general, by the geometric mean of the radius of deformation and a length scale determined by the curvature of the flow profile at the posit...

Homeostatic Tendencies of the Earth’s Atmosphere

Abstract: The atmosphere of the earth differs greatly from that of the other terrestrial planets with respect to composition, acidity, redox potential and temperature history predicted from solar luminosity. From the fossil record it can be deduced that stable optimal conditions for the biosphere have prevailed for thousands of millions of years. We believe that these properties of the terrestrial atmosphere are best interpreted as evidence of homeostasis on a planetary scale maintained by life on the surface. Some possible mechanisms of this biological homeostasis have been noted and the implications of this concept for experimental studies pointed out.