Showing papers by "Lancaster University published in 1979"
TL;DR: Potted maize seedlings were subjected to a single period of water stress and a significant accumulation of solutes in the root tips of the unwatered plants resulted in the maintenance of root turgor for the duration of the water stress treatment.
Abstract: Potted maize seedlings were subjected to a single period of water stress. As the severity of water stress increased, measurements were made of leaf and root solute and water potentials, leaf diffusive conductance and leaf and root growth. After day four of the drying cycle, the rate of leaf extension and the development of leaf area were reduced. This reduction correlated well with a reduction in leaf turgor which occurred at this time. A significant accumulation of solutes in the root tips of the unwatered plants resulted in the maintenance of root turgor for the duration of the water stress treatment. Root growth of the unwatered plants was also maintained as the severity of water stress increased. A mild degree of water stress resulted in a net increase in root growth compared to the situation in well-watered plants. The significance of solute regulation and continued root growth for plants growing in drying soil is discussed.
455 citations
TL;DR: The authors examined the effects of the organisation of curricula, teaching, and assessment on student learning and looked at the different demands which different academic environments make on their students, concluding that students in different subject areas see themselves to be studying in markedly different environments.
Abstract: This paper examines the effects of the organisation of curricula, teaching, and assessment on student learning and looks at the different demands which different academic environments make on their students. After a brief review of research into learning contexts in higher education, data from a course perceptions questionnaire are presented. The principal dimensions which students themselves use to characterise academic environments are identified. The perceptions of students in six departments at one British university are compared; it is concluded that students in different subject areas see themselves to be studying in markedly different environments. The results also suggest students' evaluations of the teaching and the courses in each department.
442 citations
TL;DR: In this article, three distinctive approaches to studying which contain elements of both study processes and motivation are reviewed. But the authors focus on the importance of characteristic styles of learning in describing the processes through which students arrive at different levels of under-understanding.
Abstract: Dimensions which have been used to describe various aspects of studying are reviewed. These draw attention to three distinctive approaches to studying which contain elements of both study processes and motivation. The development of an inventory of approaches to studying is reported which confirmed the importance of these three dimensions, but also drew attention to the importance of characteristic styles of learning in describing the processes through which students arrive at different levels of under-standing.
432 citations
TL;DR: The transfer of official bilateral economic aid has become an institutionalized dimension of the relationship between high- and low-income countries as discussed by the authors, and there is considerable confusion about the transfer process.
Abstract: The transfer of official bilateral economic aid has become an institutionalized dimension of the relationship between high- and low-income countries. There is, however, considerable confusion about...
322 citations
TL;DR: In this paper, it was found that if the drag coefficient and Reynolds number are defined empirically in terms of the arithmetic mean particle diameter, the effects of shape and rotation can be fully accounted for by defining a shape parameter, F, for each particle.
221 citations
TL;DR: In this article, a superspace with two commuting and two anti-commuting co-ordinates is discussed with particular emphasis on its superconformal properties and a complete expansion of the supervierbein is given and the local supersymmetry transformations of the component fields derived.
Abstract: A superspace with two commuting and two anti-commuting co-ordinates is discussed with particular emphasis on its superconformal properties. A complete expansion of the supervierbein is given and the local supersymmetry transformations of the component fields derived. Super Weyl transformations are defined and it is shown that (2+2)-dimensional superspace is superconformally flat. The spinning string is re-examined and the problems of previous approaches resolved.
184 citations
TL;DR: Diet is a controlling factor in several common groups of dental diseases, including those due to bacterial deposits on the teeth and to defects of dental structure, and its applications to skeletal material from Egyptian and Nubian cemeteries are described.
Abstract: Diet is a controlling factor in several common groups of dental diseases. These include those due to bacterial deposits on the teeth and to defects of dental structure. Much recent research has been carried out, so that the relationship of diet to these diseases is now well known. This allows the frequencies of occurrence of dental diseases in ancient skeletal material to be used as indicators of the diet eaten by the population during life. A description is given of the theory behind this method and an example of its applications to skeletal material from Egyptian and Nubian cemeteries.
155 citations
TL;DR: In this article, the authors established a number of models, comprising both economic and political variables, which are used in an attempt to indicate the relative saliency of rival determinants of public welfare commitment in advanced democratic states.
Abstract: The overriding conclusion of the majority of recent policy studies is that political factors play an insignificant role in influencing policy outputs. We establish a number of models, comprising both economic and political variables, which are used in an attempt to indicate the relative salience of rival determinants of public welfare commitment in advanced democratic states. Though we cannot dismiss some influence of economic factors, the main findings run counter to the conventional wisdom of policy studies in indicating the greater salience of political factors as determinants of public welfare outputs.
148 citations
TL;DR: In this paper, the importance of selective collembolan (Onychiurus subtenuis Folsom) grazing on the colonization of L layer leaf litter from a cool temperate deciduous forest by two common litter fungi (a Sterile dark form and a Basidiomycete) was assessed.
Abstract: Using simple laboratory systems, an attempt was made to assess the importance of selective collembolan (Onychiurus subtenuis Folsom) grazing on the colonization of L layer leaf litter from a cool temperate deciduous forest by two common litter fungi (a Sterile dark form and a Basidiomycete). The results indicate that relatively low selective grazing rates could have potentially important effects on the growth and competitive colonizing ability of individual fungi. The relation of such a laboratory study to actual field events is only feasible when there is a thorough knowledge of the organisms being used. Preamble In common with numerous other forest systems, detailed data have been accumulated over the last decade on various groups of organisms active in the litter layers of a cool temperate deciduous forest (Kananaskis, Alberta, Canada) where the major tree species is Populus tremuloides Michx. Detailed studies on fungi in the litter layers of this forest (Visser & Parkinson, 1975 a, b) indicate that the time of spring thaw is one of considerable and rapid change in the populations of these organisms. This change was particularly well seen when concurrent (April) replicate samples of L layer leaf litter were taken from the melting edge of snow patches and from areas where complete snow melt had occurred and fungal biomass and species complement were determined. The data obtained from this study are summarized in Table 1.
145 citations
TL;DR: In this article, the authors apply a newly developed theory to volcano observations of explosive eruptions and show that previous estimates of pre-explosion gas pressures may be overestimated by an order of magnitude.
Abstract: Application of a newly developed theory to volcanological observations of explosive eruptions shows that previous estimates of pre-explosion gas pressures may be overestimated by an order of magnitude.
143 citations
TL;DR: Street and household dusts have been sampled within the Lancaster area and analysed for Pb, Cd, Cr, Co, Cu, Ni and Zn, and the results are discussed in relation to the sources of the metals, and possible health hazards to children exposed to the dusts.
TL;DR: In this article, the authors measured the total cross section in units of the point-like e+e− → μ+μ- cross section at the highest PETRA energies and found that the observed average multiplicity, together with existing low energy data, indicate a rapid increase in multiplicity with increasing energy.
01 Dec 1979-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Sodium uptake is depressed in acids waters in both species but the depression is more pronounced in D. magna than in Cantholeberis curvirostris.
Abstract: 1.
Sodium balance has been compared in two cladocerans,Daphnia magna, which commonly frequents alkaline waters of moderate to high salt content, andAcantholeberis curvirostris, which is found in acid peaty waters of low salt content.
2.
Differences in the affinity for sodium ions exist in different populations ofD. magna. In some populations the uptake mechanisms are half saturated at concentrations of 0.2 mM Na/l but in one population this value (K) was only 0.05 mM Na/l. The sodium uptake system ofA. curvirostris has a higher affinity for sodium ions than that of any population ofD. magna, K being as low as 0.016 mM Na/l.
3.
A. curvirostris retains sodium better in acid waters than doesD. magna. In the former the rate of sodium loss at pH 3 is lower than at pH 7 while in the latter the rate of loss at pH 3 is four times that at pH 7.
4.
Sodium uptake is depressed in acids waters in both species but the depression is more pronounced inD. magna.
5.
The concentration of calcium ions in the medium has little effect on the rate of sodium loss in either species.
TL;DR: In this paper, a factorial experiment involving varied levels of soil fertility showed that when the amount of nitrogen available in the soil is low, the plants can tolerate, and even benefit from, nitric oxide in the atmosphere.
TL;DR: Accuracy was found to increase with increasing age, but no developmental trends in laterality were evident with either accuracy or vocal reaction time measures; boys showed a greater degree of visual hemifield asymmetry for accuracy than girls.
TL;DR: In this paper, three exploratory studies are reported which extend the work on approaches to learning carried out by Marton and his colleagues in Gothenburg and suggest ways in which his explanatory constructs could be elaborated to take account of the styles of learning adopted by students.
Abstract: Summary Three exploratory studies are reported which extend the work on approaches to learning carried out by Marton and his colleagues in Gothenburg. The main aim of the studies was to develop a questionnaire to investigate the way students approach the task of reading an academic article. Marton had distinguished between ‘deep’ and ‘surface’ approaches, and a coding procedure has been developed to obtain similar categories from questionnaires. These exploratory studies, while not producing statistically convincing results, did confirm the pattern of findings reported by Marton and suggest ways in which his explanatory constructs could be elaborated to take account of the styles of learning adopted by students.
TL;DR: In this paper, recursive methods are used to solve Yule-Walker equations for autoregrsssive parameters given an autocovariance function, which can be extended to the efficient solution of various sets of equations which arise in time series analysis.
Abstract: Recursive methods are commonly used to solve Yule—Walker equations for autoregrsssive parameters given an autocovariance function. The reverse procedure can be extended to the efficient solution of various sets of equations which arise in time series analysis. Those presented in this paper include computation of the autocovariance function of an ARMA model, and the Cramer—Wold factorization.
TL;DR: It is concluded that SO 2 and NO 2 in combination may be more toxic to plants than would be predicted by summing their individual effects on growth.
TL;DR: In this article, the responses of stomata on detached epidermis of Commelina communis to light and CO2 have been shown to be strongly dependent on the concentration of KCI in the incubation medium.
Abstract: . The responses of stomata on detached epidermis of Commelina communis to light and CO2 have been shown to be strongly dependent on the concentration of KCI in the incubation medium. There was a high sensitivity to the two stimuli in 50 mM KCI, but there were much reduced responses at lower and higher concentrations. It is considered that an appropriate choice of medium is essential if useful physiological studies of stomata are to be made using epidermal strips. At lower KCI concentrations, the ability of the stomata to open is thought to be limited by the availability of K+ ions, and at higher concentrations their ability to close may be affected because of an inhibition of the net efflux of K+. The production of malate was related to KCI concentration, and was largest in the medium containing zero KCI which supported poor stomatal responses to light and CO2It is concluded that malate metabolism is unlikely to play a central part in the changes in guard cell turgor that are brought about by light and CO2.
TL;DR: For instance, the authors argues that the most plausible explanation for these common properties is that our species inherits complex fixed psychological equipment which deter mines the nature of the ideas or mental structures that are accessible to us.
Abstract: Much of the impact which linguistics has had on philosophy in recent years stems from Noam Chomsky's arguments from linguistic universals to a 'nativist' or 'rationalist' account of mind. Before Chomsky, linguists tended to believe that (as Martin Joos, 1957: 96, put it) "languages [can] differ from each other without limit and in unpredictable ways". Ac cording to Chomsky this is wrong: there are certain respects in which all human languages are cut to a common pattern. The most plausible explanation for these common properties, Chomsky argues, is that our species inherits complex fixed psychological equipment which deter mines the nature of the ideas or mental structures that are accessible to us. If a language fits our inborn psychological machinery, we can learn it and use it; if it does not, we cannot. Chomsky thus uses linguistic universals to attack the view (traditional, at least in the English-speaking world) of mind as relatively plastic or adaptable; Chomsky urges us instead to assimilate our account of individuals' mental development to our account of individual physiological development, as a process in which heredity plays a role as large as or larger than that played by environment. Clearly (and Chomsky is well aware of this, e.g. 1972: 42-3) the force of the argument from linguistic universals to nativism depends critically on the lack of plausible alternative explanations for the linguistic uni versals. Some have taken this as a ground for dismissing Chomsky's argument altogether (e.g. Putnam, 1967: ?ii, (e)). That seems unreason able, since the logic of Chomsky's argument is simply that of the deductive-nomological explanations which are standard in empirical science: all scientific theories are convincing only so long as the obser ved data which they predict are not also predicted by rival and more plausible theories. It may well be true (I believe it is true) that some of the relatively peripheral universals mentioned by Chomsky, such as those having to do with phonology, can be 'explained away' without recourse to innate psychological machinery (see e.g. Liljencrants and Lindblom, 1972; Ohala, 1974); but the extant attempts to explain away the syntactic universals which have always played the central role in Chomsky's nativist arguments seem quite unsuccessful. (I survey and
TL;DR: The growth rates of Dactylis glomerata L.C. and Phleum bertolonii D.C., which are essentially lowland species in Britain, show a large response to an increase in day temperature, while those of Sesleria albicans Kit.
Abstract: SUMMARY The growth rates of Dactylis glomerata L and Phleum bertolonii DC, which are essentially lowland species in Britain, show a large response to an increase in day temperature from 10 to 20 ?C, while those of Sesleria albicans Kit which occurs from sea-level to 900 m, and Phleum alpinum L (600 to 1200 m) show little response These differences can be attributed to the greater leaf-area ratio, and to the increased rates of both leaf-initiation and leaf-expansion of the lowland species at higher temperatures Net assimilation rates are scarcely affected by temperature The differences are therefore due to morphogenetic effects and not to differences in the rates of physiological processes
TL;DR: In this article, the authors used the profiles of 137Cs, 134Cs, 106Ru, 144Ce, 95 Zr Nb and 134 Cs 137 Cs ratio in a sediment core and their discharge patterns from the Windscale Nuclear Plant to determine the net sedimentation rate on an estuarine inter-tidal bank.
TL;DR: In this paper, it was shown that in log-linear models, although the estimated relationship represents the conditional expectation of ln Y, the antilogarithm does not give the condition of Y. This has important implications in spatial analysis.
Abstract: Model specification is a crucial factor in regression. We show that in log-linear models, although the estimated relationship represents the conditional expectation of ln Y, the antilogarithm does not give the conditional expectation of Y. This has important implications in spatial analysis.
TL;DR: Learning-to-learn as mentioned in this paper ) is a systematic attempt to help students to learn more effectively, mainly in Britain and involving groups rather than individuals, and it is reviewed against the background of recent research findings on student learning.
Abstract: This paper is concerned with systematic attempts to help students to learn more effectively. Current approaches to learning-to-learn, chiefly in Britain and involving groups rather than individuals, are reviewed against the background of recent research findings on student learning. Four issues are identified and discussed: contrasting conceptions of learning-to-learn; responses to the problems posed by subject and contextual varations in learning demands; the implications of autonomy, change and the individual learner; and the relationship between research on learning and the development of approaches to learning-to-learn.
TL;DR: Experiments with the growth of callus cultures suggest that interspecific differences in the potential for cell growth do not account for the observed differences in leaf extension in P. bertolonii and P. alpinum.
Abstract: Independent temperature control of separate organs of seedling plants of Phleum bertolonji and P. alpinum indicates that the temperature of the first leaf and coleoptile exert the dominant temperature control of specific leaf area (SLA). Rates of leaf extension in the upland species P. alpinum are slower than in the lowland species P. bertolonii. This difference is related in the main to the significantly greater number of cell generations involved in the expansion of the leaf and not to the cell generation time, which does not differ between the species. Experiments with the growth of callus cultures suggest that interspecific differences in the potential for cell growth do not account for the observed differences in leaf extension. In both species the response of SLA to temperature is mainly a consequence of its influence on cell diameter. As a result it is the temperature in the region of cell expansion, within the leaf sheath, that will control SLA.
TL;DR: Using a set of 126 areal units intended to represent labour markets, this paper describes and analyses 1970–71 migration flows and identifies the largest residuals from the gravity model.
Abstract: Flowerdew R. and Salt J. (1979) Migration between labour market areas in Great Britain, 1970–1971, Reg. Studies 13, 211–231. Using a set of 126 areal units (Standard Metropolitan Labour Areas) intended to represent labour markets, this paper describes and analyses 1970–71 migration flows. It begins with a description of the most important flows between labour market areas, in both absolute and relative terms. The effects of labour market size are removed by a transaction flow analysis, and the effects of distance and size are evaluated by a gravity model. The largest residuals from the gravity model are then identified and discussed in terms of economic and other explanatory factors.