Showing papers by "University of Exeter published in 1974"
TL;DR: The parasite fauna of Britain appears to be considerably poorer in number of species than that of mainland Europe, and that of Ireland poorer still.
Abstract: One hundred and sixty eight species of parasite are listed from 36 species of freshwater fish from Britain and Ireland, and notes on their distribution are provided. A list of hosts together with the parasites recorded from them is also given. Although almost twice as many species are listed as in the most recent published reference list, the parasite fauna of Britain appears to be considerably poorer in number of species than that of mainland Europe, and that of Ireland poorer still. The distribution of most species, apart from two endemic species and a very few which have clearly been introduced into Britain in recent years from America or the mainland of Europe, appears to show no peculiarities and is probably contiguous with that of their hosts.
178 citations
TL;DR: The significance of tomatine to plants which elaborate it is discussed and some possible uses of the compound are mentioned.
132 citations
TL;DR: In this article, the authors have determined volumetrically water vapour adsorption isotherms on samples of LiF, NaF and NaCl at 278.15, 288.15 and 298.15 K.
106 citations
70 citations
59 citations
TL;DR: Photopic increment-threshold spectral sensitivity functions were behaviourally determined in three tawny owls, using a two-choice simultaneous discrimination procedure, and showed very close agreement.
58 citations
TL;DR: This paper showed that mental imagery improves free recall through strengthening of the association between items, and not by improving the distinctiveness, availability, or form of storage of the individual items, while there was no interference with subjective organization in the single image condition.
45 citations
TL;DR: In this paper, the threshold visual acuity for grating stimuli was determined in two tawny owls (a totally nocturnal avian species) at a stimulus luminance of 1·7 log mL.
43 citations
TL;DR: The EEG of each of 32 Ss was monitored during post-observation imaging to words varying in imagery, and Paivio's I-rating of words and incidental recall failed to reach significance.
Abstract: This is an exploratory correlational study of a number of variables relating to imagery The EEG of each of 32 Ss was monitored during post-observation imaging to words varying in imagery (Paivio, Yuille, & Madigan, 1968) Ss then recalled the words and completed several questionnaires The following significant correlations were obtained; (i) Paivio's I-rating of words and experienced imaging (p < 001); (i) Experienced imaging during the task and alpha abundance (EEG) (p < 005); (iii) Betts Test of Vividness of Imagery (QMI) and Gordon Test of Visual Imagery Control (p < 001); (iv) Betts QMI and incidental recall of words (p < 005); (v) Gordon test score and incidental recall (p < 005); (vi) Betts QMI and extroversion (p < 001), and (vii) extroversion and alpha abundance (p < 001) Two correlations of interest which failed to reach significance were: (i) Paivio's I-rating of words and alpha suppression, and (ii) Paivio's I-rating of words and incidental recall Both findings may be attributed to t
40 citations
TL;DR: In this article, the authors show that note-taking influences learning by ensuring that learners attend to information, providing a version of the information that is particularly valuable to the individual learner, and through direct effects of the activities involved in taking notes.
Abstract: Summary Does note‐taking by students contribute to the acquisition of knowledge? Taking notes does provide a record of information, but since there are inexpensive alternative methods of reproducing knowledge, the extensive continued use of note‐taking in education can be justified only if learning is facilitated thereby. Much of the published research takes the form of broad comparisons of recall following experimental conditions in which learners took notes or made no notes, and the majority of such studies have produced no evidence for positive effects of note‐taking. However, recent research has shown that in addition to recording information, note‐taking influences learning by (a) ensuring that learners attend to information, (b) providing a version of the information that is particularly valuable to the individual learner, and through (c) direct effects of the activities involved in taking notes. Learning is strongly influenced by the particular note‐taking strategy an individual adopts. It is sugge...
34 citations
TL;DR: A clear preference for the actinian anemones Actinia equina, Anemonia sulcata, Anthopleura elegantissima and Corynactis viridis was demonstrated in this paper.
Abstract: A clear preference for the actinian anemones Actinia equina, Anemonia sulcata and Anthopleura elegantissima was demonstrated, while the acontian anemones and Corynactis viridis ranked low in the order of preference. The significance of acontia as defensive structures in anemones is discussed briefly. No differences in food preference were found between eolids collected from Plymouth and Millport; and British Aeolidia behaved in the same way towards Californian anemones as did Californian Aeolidia.The eolids varied in their tendency to bite different species of anemone, but the performance of each individual eolid was similar in different experiments. It is possible that the individual variations may account for conflicting reports in the literature.
TL;DR: Ploughing infected debris into the soil or burning it soon after harvest are proposed as effective control measures to protect the crop of the following year from debris-borne inoculum.
Abstract: The survival of pycnidia of Leptosphaeria nodorum, the causal fungus of glume blotch disease of wheat, in debris is favoured by cool and moist conditions on the soil surface. Moisture, relative humidity, temperature and the nature of the debris are all important in determining the rate of increase in the number of pycnidia in surface debris. Ploughing infected debris into the soil or burning it soon after harvest are proposed as effective control measures to protect the crop of the following year from debris-borne inoculum.
TL;DR: In this article, the authors measured the mass transfer between an electrolyte and vertical arrays of horizontal cylinders using the limiting current electrolytic technique and found that mass transfer rate, normalized with respect to a single cylinder, either decreased or increased with array position, depending on the particular combination of experimental variables.
Abstract: Rates of mass transfer between an electrolyte and vertical arrays of horizontal cylinders have been measured using the limiting current electrolytic technique. The system used was the deposition of copper at the test cathode cylinders from an acidified cupric sulphate solution. Various combinations of solution concentration, cylinder diameter, number of cylinders and cylinder spacing have been used, including experiments on single cylinders. Results for single cylinders have been correlated by the equation. Sh0 = 0.56 (Sc Grm'd)0.25 which agrees well with previous work on both heat and mass transfer. In arrays of cylinders the mass transfer rate, normalized with respect to a single cylinder, either decreased or increased with array position, depending on the particular combination of experimental variables. This behaviour has been explained in terms of the opposing effects of the interacting concentration and velocity fields between cylinders. The findings lend support to the suggestion of Marsters [1] that a position-based Grashof number in the range 106 to 107 determines the transition between a decrease and an increase in mass transfer up an array. The results are relevant to the modelling of tubular heat exchangers in free convection dominating conditions, and also illustrate the important effect of boundary layer carry-over in determining current distribution in multi-electrode electrochemical cells.
TL;DR: In this article, 30 transparencies of representational pictures were used to judge the correctness or otherwise of each painting's orientation: only 53 per cent of these judgements were correct.
Abstract: In Expt. I 30 transparencies of representational pictures were used. Fifteen of the pictures were projected from the wrong side to produce right-left reversal. Thirty subjects judged the correctness or otherwise of each painting's orientation: only 53 per cent of these judgements were correct. In Expt. II details in 16 reproductions of abstract pictures were rearranged to form alternative versions. Paired original and altered versions were presented twice; on the first occasion the 60 subjects indicated which versions they preferred and on the second occasion they guessed which was the original version of each pair. Generally, the detection of original versions was low (62 per cent) and original versions were preferred on only 55 per cent of trials. Aesthetic experiments in which works of art have been deliberately altered are rare. It is argued that such alterations are technically feasible and may afford valuable ways of testing aesthetic theories.
TL;DR: The trophozoites of Selenidium are worm-like in appearance, and are attached by one end to the intestinal epithelium of the host, while the remainder of the organism performs rhythmic bending movements, reminiscent of nematode worms.
Abstract: The archigregarine, Selenidium, is parasitic in the digestive tracts of some polychaete worms. The trophozoites of Selenidium are worm-like in appearance, and are attached by one end to the intestinal epithelium of the host, while the remainder of the organism performs rhythmic bending movements, reminiscent of nematode worms. The trophozoites have a multilayered, longitudinally folded pellicle, and beneath this are longitudinally oriented microtubules, arranged in precise fashions. The arrangements of both the pellicle, and the microtubules change during the bending movements. Furthermore, if trophozoites are treated with the drug colchicine, the sub-pellicular microtubules are destroyed, the patterns of pellicular folding are altered, and the trophozoites cease to move. The contribution of the pellicle and the microtubules to the characteristic movements of the trophozoites is evaluated and discussed.
TL;DR: Two intra oral training appliances have been developed to assist in the treatment of patients with hypernasal speech and one of these incorporates a visual aid which is used by the patient during frequent practice at home.
Abstract: SummaryTwo intra oral training appliances have been developed to assist in the treatment of patients with hypernasal speech. One of these incorporates a visual aid which is used by the patient during frequent practice at home. This preliminary report describes their construction, discusses their possible mode of action, and indicates how they may be used.
TL;DR: In this article, an approach to the inverse problem of electromagnetic induction in spherically symmetric layered Earth models is described, where conductivity and thickness of the shell are determined for each variation separately by using the observed value of the ratio of internal to external parts of the magnetic potential at the surface of the Earth.
Abstract: Summary
An approach to the inverse problem of electromagnetic induction in spherically symmetric layered Earth models is described. In the first case single periodic variations alone are considered and it is assumed that the conductivity is uniform in a single thick shell which surrounds a perfectly conducting sphere. The conductivity and thickness of the shell are determined for each variation separately by using the observed value of the ratio of internal to external parts of the magnetic potential at the surface of the Earth. Results have been obtained by using a variational technique, for Sq variations, the 27-day variation and its harmonics, and the annual variation. In the second case several variations are used simultaneously to obtain a multilayered model. Finally the method is used to give an estimate of the maximum screening effect of the oceans.
TL;DR: This paper found that instructions to form images improved the recognition of old high I and low I nouns, but did not reduce the number of false positives, and suggested that better recognition following instructions to image is the result of images actually elicited.
Abstract: Subjects who were instructed to form images, and control subjects, were allowed an average of 3 sec./word in Expt. I and 6 sec./word in Expt. II to study a mixed list of 50 high I and 50 low I nouns. Recognition was tested upon a list containing the old words mixed with an equal number of new high I and low I nouns. Analysis of total errors showed that high I nouns were recognized better than low I nouns and that instructions to form images improved the recognition of high I nouns. Instructions to form images improved the recognition of old high I nouns, but did not reduce the number of false positives. However, high I value was associated with fewer false positives, but not with better recognition of old words. It is suggested that better recognition following instructions to image is the result of images actually elicited but that better recognition of high I than of low I nouns results from a greater semantic similarity among low I than among high I words.
TL;DR: It appeared likely that gibberellin transport, even in long young segments, was not truly polar, but could be influenced by the spatial distribution of growth centres in relation to gibb Berellin source.
Abstract: Transport of [3H]GA1 occurred freely through stem segments ranging in length from 6 mm to 8 cm. Only small amounts of radioactivity appeared in agar receiver blocks, particularly when transport in young, elongating, segments was measured. Little or no metabolism of [3H]GA1 appeared to take place during a 16 h transport period. With 6 mm segments, there was no indication of polarity in longitudinal transport. In 8 cm long segments, an apparent acropetal polarity of [3H]GA1 transport occurred in young, but not in mature, segments. However, it appeared likely that gibberellin transport, even in long young segments, was not truly polar, but could be influenced by the spatial distribution of growth centres in relation to gibberellin source.
TL;DR: In this paper, it was shown that the parents of the Nuk gneisses in the Godthabsfjord area cannot have been derived by partial or complete melting of the older Amitsoq gneses.
Abstract: SOME prominence has been given recently to the results and implications of isotope age studies1–4 in the early Precambrian rocks of the Godthab region, southern West Greenland. The studies were initiated after field investigations5 suggested that the Godthabsfjord region may contain outcrops of the oldest rocks in the earth's crust. McGregor5 has grouped these rocks into an older and a younger set of gneisses (respectively the Amitsoq and Nuk gneisses) separated in time by dykes (the Ameralik dykes), metavolcanic and metasedimentary rocks (the Malene supracrustals) and stratiform meta-anorthosites. Among conclusions drawn from the isotope work is that based on initial ratios of 87Sr/86Sr that the parents of the Nuk gneisses in the Godthabsfjord area cannot have been derived by partial or complete melting of the older Amitsoq gneisses3. We wish to comment on the applicability of this conclusion to the Nuk gneisses mapped in the area immediately to the south.
TL;DR: The present experiment supports the LIV with regard to response magnitude if resistance units are used but not if conductance is used, and argues that intra- rather than inter-subject analysis should be used when testing for the Liv.
TL;DR: Movement of both [3H]GA1 and [14C]GA3 through root segments from P. coccineus seedlings was basipetally polarised and gibberellin transport was restricted to the stele, and absent from cortical tissues.
Abstract: Movement of both [(3)H]GA1 and [(14)C]GA3 through root segments from P. coccineus seedlings was basipetally polarised. The basipetal/acropetal ratio of radioactivity from [(3)H]GA1 in agar receiver blocks was 9.2 for apical, elongating segments, and 4.0 for more basal, non-elongating segments. Polarity of gibberellin transport was restricted to the stele, and absent from cortical tissues. Transport of [(14)C]IAA through root segments to agar receivers was preferentially acropetal, particularly so in the stele. Despite the existence of basipetal polarity of gibberellin transport in the root, [(3)H]GA1 injected into cotyledons moved into and acropetally along the seedling root.
TL;DR: In this paper, the main types of reaction known for diborane are reviewed in sufficient detail, without going to the length of being fully comprehensive, and the most useful compilation of information covering the published data to 1962 or early 1963 is to be found in a chapter on the boron hydrides by Adams.
Abstract: Publisher Summary The preparative chemistry of diborane, together with its physical and molecular properties, have been reviewed recently as have its interconversion reactions to other boranes. Because of the high reactivity of diborane, the types of reaction that it undergoes are unusually numerous and varied, but during the past decade, there has been a surprising lack of reviews on its general reaction chemistry. The most useful compilation of information covering the published data to 1962 or early 1963 is to be found in a chapter on the boron hydrides by Adams. Earlier accounts of certain aspects of diborane chemistry are due to Mikhailov and Schenker. Since subsequent developments have been numerous, a reappraisal of the state of knowledge is long overdue. The present chapter attempts to cover in sufficient detail, all the main types of reaction known, without going to the length of being fully comprehensive. Diborane is a mildly endothermic compound that is only on the verge of stability at room temperature, since it slowly decomposes during prolonged storage.
TL;DR: In this article, a mathematical model is developed to describe the washing performance of partially drained filter and centrifuge cakes, and experiments were carried out in vacuum and centrifugally drained beds and the experimental data compared with computed results from the model.
TL;DR: A simple index of roundness measurement, ( 2r L ) × 100 ), based upon radius of curvature (r) and maximum length (L) is applied to 8500 pebbles sampled from glacial deposits and contemporary river channel deposits in Wensleydale, Yorkshire as mentioned in this paper.
TL;DR: Rat liver mitochondria contain an apparently substrate-specific 1-aminopropan-2-ol kinase activity and indirect evidence also indicates the presence of a phosphoryl-1-aminocerosine-3-ol cytidylyl transferase activity, suggesting a possible role for these two enzymes in the incorporation of 1-AMO as a phospholipid base.
01 May 1974
TL;DR: In this article, the authors measured the net fluxes of sodium, chloride and potassium across the gills of Anguilla dieffenbachii using an isolated, perfused preparation and found that increases in the internal sodium and chloride concentrations above those normally found in the serum resulted in an increasing net outflux of these ions.
Abstract: The net fluxes of sodium, chloride and potassium across the gills of freshwaterAnguilla dieffenbachii were measured using an isolated, perfused preparation. Reductions in the external sodium and chloride concentrations below 1.0 mMol/l resulted in an increasing net outflux of these ions from the gill (Fig. 1) whereas reductions in the internal sodium and chloride concentrations had no significant effect on the net fluxes of these ions (Fig. 2). Increases in the internal sodium and chloride concentrations above those normally found in the serum resulted in increasing net outfluxes of these ions (Fig. 2). Reductions in the internal potassium concentration below 1.0 mMol/l resulted in an increasing net outflux of sodium essentially similar to that obtained on reducing the external sodium concentration (Fig. 3). These results are discussed with reference to the possible active transport of ions across the branchial epithelium of teleosts in fresh water. In particular, the involvement of Na+/K+ exchanges in such transport processes are considered.