Showing papers by "Lancaster University published in 1987"
TL;DR: The findings demonstrate the importance of configurational information in face perception, and that configurations are only properly perceived in upright faces.
Abstract: A new facial composites technique is demonstrated, in which photographs of the top and bottom halves of different familiar faces fuse to form unfamiliar faces when aligned with each other. The perception of a novel configuration in such composite stimuli is sufficiently convincing to interfere with identification of the constituent parts (experiment 1), but this effect disappears when stimuli are inverted (experiment 2). Difficulty in identifying the parts of upright composites is found even for stimuli made from parts of unfamiliar faces that have only ever been encountered as face fragments (experiment 3). An equivalent effect is found for composites made from internal and external facial features of well-known people (experiment 4). These findings demonstrate the importance of configurational information in face perception, and that configurations are only properly perceived in upright faces.
1,265 citations
01 Jul 1987
1,140 citations
TL;DR: In drying soil, ABA can move from the roots to the epidermis and restrict stomatal aperture even when leaf water potentials and turgors remain constant, suggesting the importance of this mechanism in providing a sensitive foliar response to decreasing soil moisture is discussed.
Abstract: Zhang, J., Schurr, U. and Davies, W. J. 1987. Control of stomatal behaviour by abscisic acid which apparently originates in the roots.—J. exp. Bot. 38: 1174-1181. Two experiments indicate that abscisic acid (ABA) may influence stomatal behaviour of Commelina communis L. Stomatal conductance could not be correlated with bulk leaf ABA content but when the abaxial epidermis was assayed for ABA, small increases in ABA content correlated well with limitations of leaf conductance. Restricted conductance of the abaxial surface of leaves was associated with an increase of approximately 40 amole ABA per stomatal complex. This agrees with previously published figures. When roots of individual plants were split between two containers, drying the soil around one part of the root system restricted leaf conductance, even though leaf water relations were not affected. Increased ABA content of the epidermis coincided with increased ABA content of the roots in drying soil. Other roots of the same plant in moist soil did not show increased ABA content. These results suggest that in drying soil, ABA can move from the roots to the epidermis and restrict stomatal aperture even when leaf water potentials and turgors remain constant. The importance of this mechanism in providing a sensitive foliar response to decreasing soil moisture is discussed. Key words—Soil drying, ABA, roots, stomata, water relations. Correspondence to: Department of Biological Sciences, University of Lancaster, Bailrigg, Lancaster LAI 4YQ, U.K.
348 citations
TL;DR: The authors showed interference from distractor faces belonging to an incorrect category, even when the faces in each category are matched on physical appearance, and showed that false (face and person's actual name or occupation) pairings were better than untrue pairings.
Abstract: PH has been completely unable to recognise faces since sustaining a closed head injury some four years ago, but can recognise familiar people from their names. His performance on face processing tasks is, however, comparable to that of normal subjects if explicit recognition is not required. Thus he can make same/different identity judgements more quickly for familiar than unfamiliar face photographs, and faster matching of familiar faces is only found for identity matches involving the face's internal features. When making semantic categorisation decisions to printed names he shows interference from distractor faces belonging to an incorrect category, even when the faces in each category are matched on physical appearance. When learning to associate the occupation or the name with photographs of faces, his performance is better with true (face and person's actual name or occupation) than untrue (face and another person's name or occupation) pairings. Covert recognition can also be demonstrated f...
296 citations
TL;DR: A detailed cognitive neuropsychological investigation of the patient's ability to name objects to confrontation was carried out in an attempt to determine where his cognitive deficits might lie, suggesting that his problems in word-finding were not semantically based.
Abstract: The case of a neurological patient with severe anomic word-finding difficulties is reported. A detailed cognitive neuropsychological investigation of the patient's ability to name objects to confrontation was carried out in an attempt to determine where his cognitive deficits might lie. In contrast to the findings of recent case studies of word-finding difficulty (e.g., Howard and Orchard-Lisle, 1984), it was observed that the patient seemed to have a clear understanding of the items that he was trying to name, suggesting that his problems in word-finding were not semantically based. Indeed, the patient would often generate partial phonological information about the sought-after word, indicating that he had a specific target in mind, and this was reminiscent of 'tip-of-the-tongue' states in normal word-finding. A difficulty in retrieving complete phonological forms of words is considered as the probable locus of his anomia. A distinction is made between semantically-based and phonologically-based anomias.
268 citations
TL;DR: In this paper, it was shown that the formation of stress ethylene determines the sensivity of plants to atmospheric levels of ozone and to suggest how other air pollutants may enhance ozone-mediated leaf injury.
Abstract: Ozone has long been known to cause reductions in the yield of crops1 although the precise mechanism of how this occurs is still unclear. Recently, ozone has also been suggested as being involved in the forest decline that has occurred in central Europe2—perhaps in combination with other atmospheric pollutants or with various environmental stresses such as chilling, mineral leaching, insect predation or disease. Consequently, it is desirable that the cellular mechanisms by which ozone is toxic to both crops and conifers, and how they might be modulated by other atmospheric pollutants or environmental stresses, are fully understood. Ethylene is normally produced by all plants and in trace amounts it may interact with other plant growth substances to coordinate a wide variety of developmental processes. However, when plants experience environmental stresses they respond by liberating larger amounts of ethylene—often called stress ethylene3. We have been able to demonstrate, using pea seedlings in an experimental fumigation system4, that the formation of stress ethylene determines the sensivity of plants to atmospheric levels of ozone and to suggest how other air pollutants may enhance ozone-mediated leaf injury.
230 citations
TL;DR: The authors report the case of a nonphasic patient, VB, who suffered a left-sided neglect which affected her reading, and they show that although VB's neglect sometimes prevented the encoding of leftmost letters for identity, processes which assign positions to letters in strings on a left right spatial basis still responded to the existence of those letters.
Abstract: We report the case of a nonphasic patient, VB, who suffered a left-sided neglect which affected her reading (a condition known as “neglect dyslexia”). In text reading she often read only the right halves of lines, and in single-word reading she made errors which affected the initial letters (e.g. RIVER misread as “liver” or YELLOW as “pillow”). Neglect errors to both words and nonwords typically involved the substitution of initial letters rather than deletion or addition, resulting in errors of the same length as the target words. Comprehension of misread words matched the error rather than the target. We propose, following Shallice (1981), that “neglect dyslexia” affects the early visual analysis of letters in both words and nonwords. More particularly we propose that although VB's neglect sometimes prevented the encoding of leftmost letters for identity, processes which assign positions to letters in strings on a left-right spatial basis still responded to the existence of those letters. This ...
227 citations
TL;DR: In this article, the authors describe methods for choosing and assessing volatility forecasts using open, high, low and close prices and show that high and low prices are valuable when seeking accurate volatility forecasts.
172 citations
TL;DR: The Naivasha rhyolites represent several pulses of closely related, but subtly different, magmas as discussed by the authors, and the REE patterns are moderately LREE-enriched, with large, negative Eu anomalies.
Abstract: The Recent ( 5 per cent phenocrysts. Phenocryst minerals are quartz-sanidine-ferrohedenbergite-fayalite-titanomagnetite-ilmenite-riebeckite-arfvedsonite-aenigmatite-biotite-zircon. Ferrohedenbergite and zircon are restricted to less peralkaline, and amphibole, aenigmatite, and biotite to more peralkaline, rocks.The comendites show unusually strong enrichment in Cs, F, Hf, Nb, Rb, REE, Ta, Th, U, Y, Zn, and Zr, and extreme depletion in Mg, Ca, Ba, Co, and Sr. REE patterns are moderately LREE-enriched, with large, negative Eu anomalies. Values of LIL/HFS element ratios, such as Th/Ta and Rb/Zr, are unusually high for peralkaline rhyolites, and are consistent with a substantial crustal component in the comendites. Parameters such as LREE/HREE and Zr/Nb ratios indicate that the Naivasha rhyolites represent several pulses of closely related, but subtly different, magmas. Sanidine/glass partition coefficients for Ba, Pb, Rb, Sr, U, and the REE are presented for one specimen.Major and trace element modelling, and feldspar-rock relationships, show that closed system crystal fractionation cannot alone account for the overall compositional variations in the comendites. A model involving partial melting of variable crustal source rocks and migration of dissolved volatile-metal complexes may be appropriate at Naivasha.
171 citations
TL;DR: It is argued that repetition priming is a function of the degree of physical similarity between two stimuli and that lack of priming between different stimulus types may be attributable to lack ofPhysical similarity between prime and test stimuli.
Abstract: Three experiments investigating the priming of the recognition of familiar faces are reported. In Experiment 1, recognizing the face of a celebrity in an “Is this face familiar?” task was primed by...
171 citations
TL;DR: The bimodal Naivasha complex (central Kenya) comprises 2 suites of transitional basalts and 7 chemostratigraphic groups of comendites as discussed by the authors, which exhibit systematic trace element and isotopic variations which appear related to greater assimilation of Proterozoic amphibolite facies crust by the chemically more evolved rock types.
Abstract: The bimodal Naivasha complex (central Kenya) comprises 2 suites of transitional basalts and 7 chemostratigraphic groups of comendites. The early basalt series (EBS) predates the Group 1 comendites with the later series (LBS) erupted between Groups 5 and 6. Basalts from both suites are notable for their relatively radiogenic 207Pb/204Pb isotope ratios which are higher than in the majority of ocean island basalt (OIB, Zindler & Hart, 1986), and 87Sr/86Sr ratios more radiogenic than basalts from northern Kenya. Both basalt suites exhibit systematic trace element and isotopic variations which appear related to greater assimilation of Proterozoic amphibolite facies crust by the chemically more evolved rock types. Their mantle source regions show evidence of residual plagioclase and have a 'Dupal'-like OIB trace element and Pb-Sr-Nd isotope signature (Hart, 1984). A contribution from the sub-continental lithosphere is proposed in basalt genesis.The seven comendite groups have distinct trace element and isotope systematics. Hydration of comendite glass causes significant changes in Sr and Pb isotope ratios. In terms of their Sr-Nd isotope relationships the unaltered comendites could be derived from the basalts by an assimilation-fractional crystallization (AFC) process dominated by the fractional crystallization of feldspars. However, the Pb systematics clearly demonstrate that the basalts and comendites are not part of a cogenetic suite. Chemical variations within individual comendite groups are predominantly the result of fractional crystallization of the observed phenocryst assemblages (i.e. alkali feldspar dominated) and minor crustal interaction. The majority of the chemical and isotopic differences between Groups 1-7 cannot be explained by fractional crystallization and appear to represent crustal melts derived from close to the interface between Pan African basement and the overlying Miocene-Holocene volcanoclastic rocks, at approximately 6 km depth (KRISP working group, 1987).Halogens play a fundamental role in the petrogenesis of the comendites (Cl+F<1·7 per cent) permitting small degree melts of low viscosity to be extracted from the crust and causing the breakdown of minor phases e.g, zircon. These factors explain the extreme enrichment of certain incompatible trace elements (Zr<2500, Nb<700) in the comendites and coupled with the retention of zircon in the source of the halogen poor comendites (Group 1<0·6 per cent Cl+F) result in notable fractionation among the HFSE (Zr/Nb 1·5-5·5). Halogens may be concentrated in the source region from the surrounding crust by the presently active hydrothermal system. Each of the chemostratigraphic comendite groups is chemically distinct, implying that partial melting of the heterogeneous crust is on a limited scale and that no extensive magma chambers exist beneath Naivasha.
TL;DR: The eruptions of Mount Etna in 1981 on the north flank and 1983 on the south flank of the volcano were of strikingly different character as mentioned in this paper, the former was a short duration, high effusion rate eruption producing for the most part a simple flow-field; the latter was of relatively long duration and low effusion rates, producing a compound flow field of overlapping flows.
Abstract: The eruptions of Mount Etna in 1981 on the north flank and 1983 on the south flank of the volcano were of strikingly different character. The former was a short duration, high effusion rate eruption producing for the most part a simple flow-field; the latter was of relatively long duration and low effusion rate, producing a compound flow-field of overlapping flows.
TL;DR: Results of some recent research into queueing models are applied to the hospital waiting-list problem to give some important insights into the likely implications of attempts to reduce waiting lists.
Abstract: Results of some recent research into queueing models are applied to the hospital waiting-list problem to give some important insights into the likely implications of attempts to reduce waiting lists.
TL;DR: A general approach to state variable feedback pole assignment for linear discrete-time systems based on the definition of a non-minimal state space (NMSS) whose state variables are defined only in terms of the present and pastvalues of the system output and the past values of its input.
Abstract: The paper describes a general approach to state variable feedback pole assignment for linear discrete-time systems. This is based on the definition of a non-minimal state space (NMSS) whose state variables are defined only in terms of the present and past values of the system output and the past values of its input. In more conventional block-diagram terms, it can be interpreted as an extension to a proportional-integral (PI) control system in which linear feedback and forward path digital filters are introduced to ensure the required closed-loop pole assignment, For this reason, we refer to it as a proportional-integral-plus or PIP system. The paper discusses the conditions for pole assignability. Practical examples which illustrate the performance of the PIP system in fixed gain and self tuning/adaptive applications are also discussed.
TL;DR: The finding demonstrates that prosopagnosic patients may covertly achieve relatively precise recognition of familiar faces and access to semantic information.
TL;DR: Farmyard manure applied to some experimental plots at Rothamsted appears to have been a more significant source of Cd than combined atmospheric and phosphate fertiliser inputs and organic matter had a larger effect on Cd concentration than pH and the effects of pH were not consistent.
TL;DR: There was marked diurnal variation in free-ABA content of leaves and roots of plants that had been flooded for several days, with maximum contents recorded 3 h or more after the beginning of the light period and very rapidly after the lights were switched off, ABA contents declined.
Abstract: Zhang, J. and Davies, W. J. 1987. ABA in roots and leaves of flooded pea plants.—J. exp. Bot. 38: 649-659. Roots of potted pea (Pisum sativum L. cv. Feltham First) seedlings were flooded with tap water. Within a few hours of the start of the flooding treatment the content of free ABA in roots increased compared to contents of roots of unflooded control plants but this increase was not statistically significant until the beginning of the second day after flooding. Approximately 36 h after first flooding significant increases in the free-ABA content of leaves were detected. This was 14 h after significant increases in the amount of ABA in the roots of the same plants. There was marked diurnal variation in free-ABA content of leaves and roots of plants that had been flooded for several days, with maximum contents recorded 3 h or more after the beginning of the light period. Very rapidly after the lights were switched off, ABA contents declined. On day 3 of the flooding treatment, there was more than a 5-fold decrease in the free-ABA content of leaves within a few hours of the beginning of the dark period. Radio-immunoassay suggested that a very large proportion of the total ABA in the plant was in a bound form. This form of ABA increased substantially as the flooding period progressed. The importance of variation in ABA content for the control of water relations and gas exchange of flooded plants is discussed.
TL;DR: In this article, the authors assessed the factors most important in determining fountain height in Hawaiian-type basaltic eruptions on the basis of theoretical calculations and observations at Pu'u 'O'o vent, east rift zone of Kilauea, Hawaii.
Abstract: Factors most important in determining fountain height in Hawaiian-type basaltic eruptions were assessed on the basis of theoretical calculations and observations at Pu'u 'O'o vent, east rift zone of Kilauea, Hawaii. It is shown that fountain height is very sensitive to changes in exsolved gas content (and, thus, can be used to estimate variability in exsolved gas content) and relatively insensitive to large variations in volume flux. Volume flux was found to be the most important parameter determining the equilibrium vent diameter. The results of calculations also indicate that there was a general increase in magma gas content over the first 20 episodes of the Pu'u 'O'o eruption and that gas depletion took place in the conduit beneath the vent during repose periods.
TL;DR: A tutorial on the socket interprocess communication facility provided with 4.2 BSD Unix systems is presented, explained and illustrated by development of a simple socket application that provides a datagram-based remote command execution facility.
01 Jan 1987
TL;DR: Investigation of the response of ascorbate peroxidase and glutathione reductase activities in peas shows that plants respond similarly to a high concentration of a single air pollutant (ozone) and to mixtures of air pollutants when individual concentrations are low.
Abstract: The response of ascorbate peroxidase and glutathione reductase activities in peas (Pisum sativum var. Waverex) was investigated after three weeks of exposure to mixed fumigations with S02, NO, and O, (0.050 parts per million each) and increasing concentrations of O, (0-0.150 parts per million). The results show that plants respond similarly to a high concentration (0.150 parts per million) of a single air pollutant (ozone) and to mixtures of air pollutants (S02, NO: and O,) when individual concentrations are low (0.050 parts per million each). In both cases, levels of ascorbate peroxidase and glutathione reductase activites were approximately twice those to be found in plants grown in charcoal-filtered air (p 0.01).
TL;DR: The potential use of honey as an indicator in mineral prospecting and environmental contamination studies has been investigated in this paper, where the elemental content of honeys was investigated in relation to that in the soils collected from within the foraging area.
Abstract: The potential use of honey as an indicator in mineral prospecting and environmental contamination studies has been investigated. Silver, Cd, Cu, and Pb levels are reported in honeys collected throughout the U.K. The elemental content of honeys was investigated in relation to that in the soils collected from within the foraging area. For samples collected over two seasons the following concentrations were found Ag <0.1 to 6.5 ng g−1 (d.w.); Cd <0.3 to 300 ng g−1; Cu 35 to 6510 ng g−1; Pb <2 to 200 ng g−1. Considerable spatial and seasonal fluctuations were apparent. No correlations were observed between honey and soil concentrations for either Cu or Pb. It is concluded that the low concentrations of heavy metals in honey and their inherent variability (due to differences in floral source, foraging range, entrapment of atmospheric particulates on the flower, etc.) detract from the reliable use of honey as a monitoring tool. The relative merits of honeybees, pollen and beeswax for environmental monitoring or biogeochemical prospecting studies are also briefly discussed.
TL;DR: Research into the automatic recognition of anaphoric features in English is illustrated by an examination of the pronoun “ it”, and simple surface rules are proposed for identifying non-referential usages of “it”.
TL;DR: This article reported that dysgraphic handwriting errors occur at several levels in the output system which suggests that the role of sensory feedback is a complex one, but current models are not well enough specified to help us discriminate between these.
06 Jul 1987
TL;DR: A methodology and associated software system for the construction of a large lexicon from an existing machine-readable (published) dictionary and the utility of the Longman Dictionary of Contemporary English as a suitable source dictionary for the target lexicon is evaluated.
Abstract: We describe a methodology and associated software system for the construction of a large lexicon from an existing machine-readable (published) dictionary. The lexicon serves as a component of an English morphological and syntactic analyser and contains entries with grammatical definitions compatible with the word and sentence grammar employed by the analyser. We describe a software system with two integrated components. One of these is capable of extracting syntactically rich, theory-neutral lexical templates from a suitable machine-readable source. The second supports interactive and semi-automatic generation and testing of target lexical entries in order to derive a sizeable, accurate and consistent lexicon from the source dictionary which contains partial (and occasionally in-accurate) information. Finally, we evaluate the utility of the Longman Dictionary of Contemporary English as a suitable source dictionary for the target lexicon.
Journal Article•
TL;DR: The development of a dictionary support environment linking a restructured version of the Longman Dictionary of Contemporary English to natural language processing systems is described and an evaluation of the utility of the grammar coding system for use by automatic natural language parsing systems is offered.
Abstract: This article focusses on the derivation of large lexicons for natural language processing. We describe the development of a dictionary support environment linking a restructured version of the Longman Dictionary of Contemporary English to natural language processing systems. The process of restructuring the information in the machine readable version of the dictionary is discussed. The Longman grammar code system is used to construct 'theory neutral' lexical entries. We demonstrate how such lexical entries can be put to practical use by linking up the system described here with the experimental PATR-II grammar development environment. Finally, we offer an evaluation of the utility of the grammar coding system for use by automatic natural language parsing systems.
TL;DR: In this article, it is shown that service industries were of considerable importance even during the supposed heyday of the Victorian manufacturing industry, and that the crucial role of especially financial services cannot be understood separately from the broader Makler or middleman economy which in part predated the extensive growth of manufacturing industry.
Abstract: Five related issues involved in the analysis of services are discussed. First, it is shown that it is incorrect to suggest that there is a single route to the contemporary economy with high employment in the service sector. The Fisher–Clark thesis is discussed and criticised. In the specific case of the United Kingdom it is shown that service industries were of considerable importance even during the supposed heyday of Victorian manufacturing industry. This is shown by analysing certain regional indicators. It is further suggested that the crucial role of especially financial services cannot be understood separately from the broader Makler or middleman economy which in part predated the extensive growth of manufacturing industry. Second, some of the recent arguments of Gershuny and Miles are analysed. It is shown that their formulations are insufficiently social, both in the sense of ignoring changes in the social relations underpinning capitalist production both of manufacturing and of service industries...