Showing papers by "University of York published in 1986"

Disappointment and Dynamic Consistency in Choice under Uncertainty

Abstract: The central proposition of disappointment theory is that an individual forms expectations about uncertain prospects, and that if the actual consequence turns out to be worse than (or better than) that expectation, the individual experiences a sensation of disappointment (or elation) generating a decrement (or increment) of utility which modifies the basic utility derived from the consequence. By incorporating a simple disappointment-elation function into a model of individual choice, many observed violations of conventional expected utility axioms-including violations of Savage's sure-thing principle and the "isolation effect"-can be predicted and defended as rational and dynamically consistent behaviour.

Predictive value of tumor thickness in squamous carcinoma confined to the tongue and floor of the mouth

Abstract: In this review of 105 consecutive patients who underwent operation for previously untreated, N0 squamous carcinomas arising in the oral tongue or the floor of the mouth, 86 percent of the determinate patients remained alive and well 2 years after treatment. Included were 48 patients, 49 patients, and 8 patients who had T1, T2, and T3 tumors respectively. Elective cervical lymphadenectomy was performed in about a third, but tumor staging did not facilitate selection of those who were most likely to have occult metastases. For this reason, we retrospectively assessed the impact of tumor thickness using an optical micrometer to measure the thickness in millimeters of the excised tumors in routinely prepared paraffin sections. Disease-related death appears to be unusual when oral tumors are thin (2 mm or less), regardless of the tumor stage. Multivariate analysis confirms that increasing tumor thickness, rather than tumor stage, had the best correlation with treatment failure and survival. These findings need to be verified in prospective studies involving a larger patient population and other head and neck sites, but they strongly suggest that measurement of tumor thickness may be a better way to select those oral cancer patients who are most likely to benefit from elective treatment of the N0 neck.

Notes on ‘latency’ in overlap onset

Abstract: This will be in part a recapitulation and in part an extension of some of the work I did during my two years at the Katholieke Hogeschool Tilburg, explor? ing the orderliness of overlapping talk. I had been interested in overlap for a long time, and had been noticing evidence of its orderliness. But I had been looking at a few striking, indicative cases. At Tilburg I worked with a mass of materials in which overlap, in one form or another, occurred. One immediate payoff was this: In the past I had noticed that not all overlap was a matter of 'people just not listening to each other', a messy chaotic busi? ness, but to the contrary, that it could, at least now and then, here and there, be a matter of fine-grained attention. But I'd had no idea just how massively overlap is associated with such attention. In the apparent chaos of overlapping talk, I began to locate a series of systematicities which collected and ordered an enormous amount of material. I'll be talking about one of those: Transition-space onset.

The analysis and modelling of British invasions

Abstract: The SCOPE programme on the ecology of biological invasions addresses three questions: What are the factors that determine whether a species will become an invader or not? What are the site properties which determine whether an ecological system will be relatively prone to or resistant to invasion? How should management systems be developed to best advantage, given the knowledge gained by attempting to answer the first two questions? The answers that have been offered to these questions earlier, and during the course of the programme, are reviewed. The consensus is that, although certain habitat and biological features increase the probability of invasion and establishment, these features are neither necessary nor sufficient, and that the prediction of invasion is not yet feasible. These points are illustrated by examples and generalizations from a survey of British invaders. The probability that an established invader will be a pest in Britain seems to be around 10%. Mathematical modelling may help in understanding and, later, in predicting invasions. Models indicate that establishment may be more critical than spread, and that a successful invader will spread at a constant linear speed. Models and data suggest that both an accelerating rate of spread and occasional major jumps can be expected; consequently, efforts to eliminate an invader at an early stage will be the most effective.

Projection and ‘silences’: Notes on phonetic and conversational structure

Abstract: the larynx and the rib cage. These sets of movements coordinated one with an- other set in motion and work upon an air-stream. The coordination takes place in time so as to produce complex recurrent patterns of movement, the whole thing being 'driven' neurophysiologically. Utterances have a relation to linguistic elements defined at a higher level of abstraction, such as the sentence. The sentence, organized via the resources of morphology, syntax and semantics, is to be mapped on to an utterance layer. Since utterances are physical and interactive events they are subject to internal and external constraints that do not apply to sentences. These constraints de- rive from the properties of interaction such as turn-competition and exchange, together with such things as repair, and retrospective and prospective 'editing'. All of these need to be signalled, and the signals that relate to them form part of the total fabric of 'utterance'. They are produced by the same processes, phonatory, articulatory and so on, as are involved in the production of ele- ments immediately relatable to phonological and other codes, and they occur alongside and interspersed with these. So, for instance, in the case of a phonetic event such as (kh69°::'k__) the duration and tight phonatory quality of the vowel together with the final glottal closure may be of interactive relevance: so too may the high to mid level pitch-ending. But the quality (a) itself, together with the general category 'fall' of the pitch contour will be in meaning systems

Towards a phonology of conversation: turn-taking in Tyneside English

Abstract: Remarkably little is known in detail about the phonetics and phonology of naturally occurring conversational talk. Virtually nothing of interest is known of the interactional implications of particular kinds of phonetic events in everyday talk: in particular about the ways in which participants in talk deploy general phonetic resources to accomplish specific interactional tasks. This is in part a consequence of the tendency of recent research on the phonological aspect of discourse to limit itself to ‘intonation’ as an area of primary interest. This work has moved away from the type of phonological analysis, such as that of Halliday (1967), that states intonational systems in terms of grammatically defined units or sentence types. Workers such as Brazil (1975, 1978, 1981), Brown, Currie and Kenworthy (1981), and Coulthard and Brazil (1981) have pursued Bolinger's suggestion that the relationship between intonation and grammar is ‘casual not causal’ and have sought to relate ‘intonation’ to discourse categories rather than to grammatical ones. These, and similar attempts to deal with aspects of discourse phonology, have suggested some organizational features which traditional linguistic accounts have not dealt with. On the whole, however, these recent attempts have been less than satisfactory for one or more of the following reasons.

Growth substance sensitivity: The need for clearer ideas, precise terms and purposeful experiments

Abstract: The idea that growth substance-responsive cells might not have a fixed capacity to respond to a growth substance is not new, but it is an idea which has received much greater consideration in the last few years, largely as a result of a series of articles by Trewavas (1981a,b, 1982, 1983). Despite the fact that no thorough attempt has been made to explore this concept experimentally, it seems to have been accepted as a valid and useful one, even by some of Trewavas's critics (Cleland 1983). However, the term “change in growth substance sensitivity” can be shown to have several meanings, each with a very different underlying physiological mechanism. If the concept is to be developed into a productive model of the way in which plant growth and development are regulated under certain circumstances, it will be necessary to be more precise. New terms are proposed to describe some of the factors which could contribute to changes in the sensitivity of a cell to a growth substance. It is argued that much more purposeful experiments will be needed in order to establish whether changes in sensitivity do accompany some developmental processes and to probe the exact nature of these changes.

Computerized performance monitoring systems: use and abuse

Abstract: An exploratory study of computerized performance monitoring and control systems reveals both positive and negative effects. Responses of 50 clerical workers from 2 organizations with computerized monitoring were compared to 94 individuals from 3 organizations in similar jobs without computerized monitoring. The results indicate that computerized monitoring is associated with perceived increases in office productivity, more accurate and complete assessment of workers' performance, and higher levels of organizational control. Respondents indicate that managers overemphasize the importance of quantity and underemphasize the importance of quality in evaluating employee performance. Workers perceive increased stress, lower levels of satisfaction, and a decrease in the quality of their relationships with peers and management as a consequence of computerized monitoring. The relevance of existing models of performance monitoring is examined in light of these findings.

Adolescent Sexual Offenders Demographics, Criminal and Sexual Histories, and Recommendations for Reducing Future Offenses

Abstract: Sexual aggression is a serious and widespread problem in our society. Over the past 15 years considerable effort has been directed toward educating society about the problem and addressing the needs of victims of sexual crimes. Research efforts have focused on both adult and child victims and to a lesser extent on adult sexual offenders. Only recently have any research efforts focused on adolescent offenders. The present study describes the characteristics of 67 male adolescents referred to an outpatient clinic because of deviant sexual behavior. The results of this study indicate that the onset of sexually deviant interests is often in early adolescence and that an effective early treatment could reduce the widespread incidence of sexual crimes and prevent future victimization in our society.

The population and community ecology of invading insects

Abstract: Theory is equivocal about invasion success, implicating various combinations of r, a population's intrinsic rate of increase, K, its `carrying capacity', enemy-imposed death rates and the coefficient of variation in population numbers as determinants of establishment. Data for a wide variety of organisms, both vertebrates and invertebrates (including insects), accidentally or deliberately introduced by man into the British Isles, appear to show that the probability of establishment of an invader is positively correlated with body size. These data are consistent with the idea that the amplitude of population fluctuations is the main determinant of invasion success, but not with theoretically expected effects of r or K (because populations of small organisms generally fluctuate more than populations of large organisms, but both r and K decrease with increasing body size). However, data for various insect orders introduced into Britain show exactly the opposite trend, with probability of establishment decreasing with increasing body size, and hence possibly with decreasing r and/or K. Possible reasons for these contradictory results, including biases in the data, are discussed. Finally, data from a variety of sources, including insects released as biological control agents, show that enemies (parasitoids and predators) are often a cause of failure to establish particular species of introduced insects. These data add further to the uncertainty about the main determinants of invasion ability. The only clear conclusion to emerge from a combination of theoretical and empirical studies is that r alone is not obviously the main, or even an important determinant of invasion success.

Non-invasive measurement of nutrient uptake by single cultured pre-implantation mouse embryos

Abstract: The uptake of pyruvate and glucose by single, cultured mouse embryos has been measured non-invasively throughout the pre-implantation period. The embryos, derived from CBA x C57F1 females and F1 males were removed from the oviducts on day 1 or day 2 following mating, and cultured to the blastocyst stage in M16 medium. Each day they were removed from culture and incubated in 20 nl medium M2 for 3 h. Serial approximately 0.5-nl samples were analysed for pyruvate and glucose by an ultramicrofluorescence technique. Pyruvate uptake exceeded that of glucose until the 8-cell/morula stage, when glucose consumption increased dramatically. The morphological development and patterns of nutrient uptake by embryos removed on day 2 resembled more closely those of freshly collected embryos than of embryos removed on day 1. These methods will enable the biochemistry of early embryos to be monitored non-invasively prior to transferring them into the uterus of recipient females.

Performance correlates of self-reported cognitive failure and of obsessionality

Abstract: In six experiments, two performance tests, measuring a number of aspects of attention, were administered to 129 people from the general population. Self-reported cognitive failure, and a measure of obsessional personality, were related to one particular measure of attention. There was evidence that individuals with low cognitive failure show different patterns of attention when anxious, as compared with high scorers; this may underlie differences in vulnerability to environmental stresses.

A generalized approach to the calculation of ro-vibrational spectra of triatomic molecules

Abstract: A generalization of the well known atom-diatom scattering hamiltonian to a coordinate system of two lengths and an angle is derived, another special case of which is a previously known bond angle-bond length hamiltonian. Different axis embeddings are also considered. The formalism is applied to the ro-vibrational levels of D2H+, CH+ 2 and HDHe (A 1 A′) and the advantage of a judicious choice of coordinates demonstrated. The vibrational band origins for HDHe*, the first predictions for this system for which previous calculations had failed, are obtained using a new geometrically defined coordinate system. It is suggested that these coordinates might be used to represent isotopically substituted van der Waals complexes.

Level of postassault sexual functioning in rape and incest victims.

Abstract: In a systematic study, 372 sexual assault survivors and 99 women with no history of sexual assault were interviewed with regard to their sexual histories to determine the incidence and types of sexual dysfunctions in these two samples. The women also completed the Sexual Arousability Inventory. Of the sexual assault survivors, 58.6% of the women were experiencing sexual dysfunctions, with 71% of them reporting that their sexual assaults were related to their development of sexual problems. In contrast, only 17.2% of the nonassaulted women reported experiencing any sexual problems. Differences in the types of sexual problems experienced by the two samples are noted, as are treatment implications. The sensitivity of the Sexual Arousability Inventory to assault-related sexual dysfunctions was affected by the educational level of the sexual assault survivors.

Feline maternal taurine deficiency: effect on mother and offspring.

Abstract: Adult female cats were fed a defined purified diet (taurine-free) either alone or supplemented with 0.05% taurine for at least 6 mo prior to breeding. The reproductive performance by the taurine-depleted females was poor, whereas those receiving dietary taurine had normal pregnancies and deliveries. The taurine-depleted females suffered from severe retinal degeneration, including a large loss of photoreceptor outer segments, and degeneration of the tapetum lucidum, and greatly reduced concentrations of taurine in their body tissues and fluids. Surviving offspring from the taurine-depleted mothers exhibited a number of neurological abnormalities and substantially reduced concentrations of taurine in the body tissues and fluids. Except for greater concentrations of cystathionine in neural tissues, other free amino acids in tissues were unaffected. The specific activities of a number of enzymes involved in the biosynthesis of taurine were unchanged in liver and brain. The composition of maternal milk, total protein, protein amino acids and free amino acids was unchanged except for taurine content, suggesting that the abnormalities in the offspring resulted from the diminished dietary taurine.

Migration of the schistosomula of Schistosoma mansoni in mice vaccinated with radiation-attenuated cercariae, and normal mice: an attempt to identify the timing and site of parasite death.

Abstract: The migration of the schistosomula of Schistosoma mansoni labelled with [75Se]methionine, has been followed from the skin to the hepatic portal system. Parasites were detected in all mouse tissues by compressed organ autoradiography. Two separate experiments were performed to track parasites in normal mice, and in mice previously vaccinated with irradiated cercariae. In normal mice, the profile of numbers of autoradiographic foci detected in the skin, lungs, systemic and splanchnic organs was described with time post-infection. The distribution of parasites to systemic organs, following exit from the lungs, paralleled the fractional distribution of cardiac output. Accumulation of schistosomula in the hepatic portal system was complete by day 21 post-infection. Only 2-3 passes of parasites around the vascular system would be required to produce the hepatic portal population. No significant decline in total foci was detected in the first 12 days post-infection. The majority of parasite elimination appeared to occur in the lungs as late as day 21, with lesser proportions in the systemic organs and skin infection site. The pattern of migration in vaccinated mice was similar to that in normal animals. One difference observed was the longer duration of stay in the skin; however, the majority of parasites eventually reached the lungs. The systemic phase of migration occurred on a reduced scale, as did accumulation of parasites in the hepatic portal system. The decline in total foci in vaccinated mice commenced approximately 7 days earlier than in normal mice and proceeded to a lower end-point. Again the majority of parasite elimination appeared to occur in the lungs with lesser proportions in the systemic organs and skin infection site. It is suggested that resistance to reinfection in vaccinated mice has two additive components which combine to retard the migration of schistosomula within the vasculature, preventing them from reaching the hepatic protal system.

A history of architectural conservation. The contribution of English, French German and Italian thought towards an international approach to the conservation of cultural property

Abstract: Investigates the history and development of major national european philosophies with respect to historic buildings, monuments and sites, the cross fertilization of these ideas, and their contribution towards an international approach in the treatments of historic structures. Illustrated by case studies from rome, athens durman (england, magdeburg (prussia), and vezelay (france). The study distinguishes between the traditional approach to the treatment of historic monuments the romantic restoration (established in the italian renaissance and developed in the 19th century), the conservation movement and modern conservation theory as reflected in the venice chapter (1964). Extensive notes, bibliography. List of librairies containing documentary materials.

Effect of benomyl on leaf phosphorus concentration in alpine grasslands: a test of mycorrhizal benefit

Abstract: Summary Phosphate and the fungicide, benomyl, were applied to two alpine grasslands in the Kananaskis Valley, Alberta, Canada, to test the hypothesis that a reduction in leaf phosphorus concentration should result from reduction in vesicular-arbuscular mycorrhizal (VAM) infection if mycorrhizal hyphae are the main route of P uptake by roots. Benomyl successfully reduced infection in the roots of several species. At one site the result was an increase and not a decrease in leaf N and P concentrations, which was directly proportional to the original infection level, implying a benefit to the plant from the reduction in infection. At the other site, opposite trends were observed before and after a severe drought episode, implying that infection was initially deleterious and later beneficial. These results are adduced as evidence to support a hypothesis that VAM infection is only beneficial to plants under particular environmental conditions or at specific times in the year or life-cycle.

Children's concept of word

Abstract: The development of the concept of word as a unit of speech is a metalinguistic insight that usually corresponds to the acquisition of literacy skills. Further, as a fundamental aspect of language structure, it converges as well with skills involved in bilingualism. A framework that describes the structure of metalinguistic awareness is applied to this task in order to relate the development of word concept to literacy and bilingualism. Children between 4 and 6 years old who are prereaders or early readers, and bilingual or monolingual, are given three tests of word concept. The results show that concept of word emerges gradually and is evident to some extent even in the 4-year-olds. Further, literacy and bilingualism are shown to promote specific aspects of its development

Spatial and temporal patterns of root activity in a species-rich alluvial grassland.

Abstract: The time and depth of activity of a number of co-existing grassland plants was measured using a technique involving the simultaneous injection to different depths in soil of 3 chemical tracers — Li, Rb and Sr. Root activity at a particular depth was assessed from the concentration of each tracer in leaf tissue.