Showing papers by "Northampton Community College published in 1998"

The ecological validity of tests of executive function.

Abstract: Ninety-two mixed etiology neurological patients and 216 control participants were assessed on a range of neuropsychological tests, including 10 neuropsychological measures of executive function derived from 6 different tests. People who knew the patients well (relatives or carers) completed a questionnaire about the patient's dysexecutive problems in everyday life, and this paper reports the extent to which the tests predicted the patients' everyday life problems. All of the tests were significantly predictive of at least some of the behavioral and cognitive deficits reported by patients' carers. However, factor analysis of the patients' dysexecutive symptoms suggested a fractionation of the dysexecutive syndrome, with neuropsychological tests loading differentially on 3 underlying cognitive factors (Inhibition, Intentionality, and Executive Memory), supporting the conclusions that different tests measure different cognitive processes, and that there may be limits to the fractionation of the executive system.

Supporting scenario-based requirements engineering

Abstract: Scenarios have been advocated as a means of improving requirements engineering yet few methods or tools exist to support scenario based RE. The paper reports a method and software assistant tool for scenario based RE that integrates with use case approaches to object oriented development. The method and operation of the tool are illustrated with a financial system case study. Scenarios are used to represent paths of possible behavior through a use case, and these are investigated to elaborate requirements. The method commences by acquisition and modeling of a use case. The use case is then compared with a library of abstract models that represent different application classes. Each model is associated with a set of generic requirements for its class, hence, by identifying the class(es) to which the use case belongs, generic requirements can be reused. Scenario paths are automatically generated from use cases, then exception types are applied to normal event sequences to suggest possible abnormal events resulting from human error. Generic requirements are also attached to exceptions to suggest possible ways of dealing with human error and other types of system failure. Scenarios are validated by rule based frames which detect problematic event patterns. The tool suggests appropriate generic requirements to deal with the problems encountered. The paper concludes with a review of related work and a discussion of the prospects for scenario based RE methods and tools.

Relationships between flowering phenology, plant size and reproductive success in Lotus corniculatus (Fabaceae)

Abstract: Over three years the flowering phenology of individuals of Lotus corniculatus has been studied in relation to fruit set and seed predation to determine the relationships between four components of flowering time, plant size and reproductive success. Timings of first and peak flowering, and duration and synchrony of flowering differed between individuals in the same years. Between years, timing of first flowering was highly correlated for the same individuals, and was closely correlated with plant size and duration of flowering–larger plants flowered earlier and for a longer period. Peak flowering and synchrony were not correlated between-years for individuals. Fruit production and seed predation were correlated with some of the components of flowering phenology in some years, but not in others. The inconstancy of these relationships suggests that directional or stabilising selection is not acting consistently on the aspects of reproductive success studied in this work. The inconstancy of selection may result in the rather asynchronous flowering phenologies of individuals of L. corniculatus observed. We emphasize the importance of studying different components of flowering phenology in relation to individual plant size over several seasons. This work has shown that plant size not only has a direct effect on individual plant fecundity but also can influence flowering time and hence indirectly affect reproductive output.

A Stochastic Model Underlying the Chain-Ladder Technique

Abstract: This paper presents a statistical model underlying the chain-ladder technique. This is related to other statistical approaches to the chain-ladder technique which have been presented previously. The statistical model is cast in the form of a generalised linear model, and a quasi-likelihood approach is used. It is shown that this enables the method to process negative incremental claims. It is suggested that the chain-ladder technique represents a very narrow view of the possible range of models.

Forest edges and habitat selection in birds : a functional approach

Abstract: Edge effects encompass a complex panoply of biotic and abiotic phenomena across woodland borders. I identify four main explanations which have been proposed to explain avian habitat selection with respect to forest edges: 1) individualistic resource and patch use, 2) biotic interactions; 3) microclimate modification and 4) changes in vegetation structure. 1) relates nest site location in woodlands relative to the edge to the proximity of food resources. It is shown that. all other things being equal, birds which are wholly dependent on resources found within woodlands will tend to avoid forest edges. Woodland species dependent upon resources found in adjacent habitats will tend to be found near to edges to enable their exploitation. 2) identifies competition, predation and brood parasitism as factors which have the potential to influence bird habitat selection near edges. 3) identifies microclimate modification as a potential influence which may act directly on nesting success or indirectly through its effects on food supply; 4) relates the activities of birds. such as nesting, feeding or use of song posts, to vegetation structure and/or floristic composition at the edge. Research on edge effects of birds in woodland has provided few practical recommendations to conservation managers. Forest edge management needs to take into account the multiple cause and effects which influence habitat selection at the edge and to target species of conservation concern.

The opportunity costs of childbearing: more than mothers business.

Abstract: "This paper is an argument about gender relations. It takes the entwined themes of men's interests in parenthood, the sex division of labour and its evolution, policy for gender equity and policy to support the level of social reproduction. The emphasis on women's employment as a determinant of low fertility has to be supplemented by an examination of the assumption that only women's time use is affected by child-rearing.... Descriptive evidence about the paid and unpaid work of couples and parents is presented, largely secondary material from the UK."

Poor readers' ability to detect speech rhythm and perceive rapid speech

Abstract: Recent research indicates that the rhythmic properties of speech may indicate to the infant listener where word boundaries are most likely to occur. However, rhythmic awareness is not included in present discussions of phonological awareness. It is suggested that skills which develop in early infancy to facilitate speech perception (i.e. awareness of rhythm) may have an impact upon later phonological development and literacy. This paper outlines a cross-sectional study, designed to examine whether poor readers do show a specific insensitivity to rhythm in speech, and whether they also exhibit signs of inefficient speech perception. Thirty primary school children identified as poor readers were matched for age and gender, and for reading age and gender with two groups of children reading at a level comparable with their chronological age (“normal” readers) (N = 90). All children completed a battery of tasks, including an assessment of rapid speech perception, rhythmic awareness, rhyme detection and phoneme deletion. The results suggest that poor readers do experience a developmental delay on rhythmic awareness, although there is no significant difference in the children's ability to perceive speech once vocabulary is taken into account. Suggestions are made regarding the need to consider non-segmental skills in definitions of phonological awareness, and how this may contribute to our understanding of phonological development.

Changing worlds: the microgeographies of young teenagers

Abstract: Few geographical studies have explicitly examined the place use and place behaviour of young teenagers, especially within the UK. In this article we report on a survey of a group of 13 year olds, living in a socially and economically deprived neighbourhood in Midland England. Attention focuses on the ‘fourth environment’ that is how these teenagers come into contact with a range of everyday places beyond their home, school and playground. For each individual, the sum of this relationship constitutes a microgeography, which when grouped together provides a spatio-temporal map of experience. The results suggest four recurrent themes, which we present as important aspects of the microgeography of this group of teenagers. We label these as: worlds apart; emblems of difference; special places; and landscapes of powerlessness. The environments of teenagers are not just appendages of the adult world, but are special places, created by themselves and invested with their own values. We argue that teenagers are not adults in waiting but are active cultural producers in their own right. When discussing the results we draw upon research and concepts in cognate disciplines to provide additional insights into teenagers' microgeographies.

British research into the increased vulnerability of young gay men to eating disturbance and body dissatisfaction

Abstract: Forty-one young gay British males (aged between 15 and 25 years) and 47 heterosexual men were compared on measures of eating disturbance and body dissatisfaction. All participants completed a questionnaire containing a number of previously validated scales including EAT-26, the BSS and a series of line-drawings. Gay participants scored higher on all measures of eating disturbance and were more dissatisfied with their bodies. The gay sample chose ideal images that were significantly slimmer than the heterosexuals and were much more likely to show symptoms of a clinical disorder. Results from gay participants revealed strong correlations between levels of eating disturbance, self-esteem and body dissatisfaction whilst these relationships did not achieve significance for heterosexuals. The findings strongly confirm American research that suggests that gay men are particularly vulnerable to serious eating disturbance. Potential explanations and implications of these findings for gay men and those who work with them are briefly discussed. © 1998 John Wiley & Sons, Ltd and Eating Disorders Association.

CREWS-SAVRE: Scenarios for Acquiring and Validating Requirements

Abstract: This paper reports research into semi-automatic generation of scenarios for validating software-intensive system requirements. The research was undertaken as part of the ESPRIT IV 21903 ‘CREWS’ long-term research project. The paper presents the underlying theoretical models of domain knowledge, computational mechanisms and user-driven dialogues needed for scenario generation. It describes how CREWS draws on theoretical results from the ESPRIT III 6353 ‘NATURE’ basic research action, that is object system models which are abstractions of the fundamental features of different categories of problem domain. CREWS uses these models to generate normal course scenarios, then draws on theoretical and empirical research from cognitive science, human-computer interaction, collaborative systems and software engineering to generate alternative courses for these scenarios. The paper describes a computational mechanism for deriving use cases from object system models, simple rules to link actions in a use case, taxonomies of classes of exceptions which give rise to alternative courses in scenarios, and a computational mechanism for generation of multiple scenarios from a use case specification.

Reasoning biases in delusion-prone individuals

Abstract: Objectives. The objective was to test whether individuals high in delusional ideation exhibit a reasoning bias on tasks involving hypothesis testing and probability judgments. On the basis of previous findings (e.g. Garety, Hemsley & Wessely, 1991), it was predicted that individuals high in delusional ideation would exhibit a ‘jump-to-conclusions’ style of reasoning and would be less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. Design. A non-randomized matched groups design was employed enabling the performance of the delusion prone individuals to be compared to that of a control group. Method. Forty individuals, selected from the normal population, were divided into groups high and low in delusional ideation, according to their scores on the Peters et al. Delusions Inventory (Peters, Day & Garety, 1996), and were compared on two tasks involving probability judgment and two tasks involving hypothesis testing. Results. Although no significant differences were found on tasks involving hypothesis testing and the aggregation of probabilistic information, it was found that individuals high in delusional ideation had a ‘jump-to-conclusions’ style of data gathering and were less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. Conclusions. In conclusion, although individuals high in delusional ideation were not found to have a general reasoning bias, some evidence of a more specific bias was found. It is thought that these aberrations may play some role in delusion formation in schizophrenia and paranoia.

Impact of life events on the onset of vitiligo in adults: preliminary evidence for a psychological dimension in aetiology

Abstract: The present study retrospectively examines the role of stressful life events in the onset of vitiligo in adults. A matched clinical sample of patients with other forms of disfigurement or skin disease (dystrophic epidermolysis bullosa and naevi, not thought to be associated with stress) served as a control group. Newly diagnosed patients and matched controls were thus asked to complete the 12-month version of the Schedule of Recent Experience, a questionnaire which measures the frequency and number of stressful life events occurring over a specified period. The results suggest that such patients endure a significantly higher number of stressful life events than do controls, suggesting that psychological distress may have contributed to the onset of their condition. The implications of the results are discussed and suggestions made for future research.

Pre-school phonological awareness and subsequent literacy development

Abstract: There is an unresolved debate in the developmental literature regarding whether phonemic awareness is acquired naturally as part of phonological awareness, or whether it is instead an artefact of reading tuition. This ambiguity affects the interpretation of studies which show that pre‐literate phonemic awareness is a powerful predictor of literacy attainment in school. There is also evidence to suggest that spoken word recognition might contribute to literacy development. The present study therefore initially assessed 30 preschool, pre‐literate children on a battery of tests designed to provide a profile of pre‐literate phonological awareness. The reading and spelling ability of these children was then monitored at the end of each school term for five terms. Results suggest that young children can develop phonemic awareness before beginning reading or attending school, and that children's pre‐literate rhyme detection ability is the best predictor of initial reading development. Spoken word recogn...

History of SAW devices

Abstract: This paper gives a historical account of the development of Rayleigh-wave, or surface acoustic wave (SAW), devices for applications in electronics. The subject was spurred on initially by the requirements of pulse compression radar, and became a practical reality with the planar interdigital transducer, dating from 1965. The accessibility of the propagation path gave rise to substantial versatility, and a huge variety of devices were developed. Passive SAW devices are now ubiquitous, with applications ranging from professional radar and communications systems to consumer areas such as TV, pagers and mobile phones. The paper describes the extensive work, particularly in the 1970s, to investigate SAW propagation in crystalline media, including piezoelectric coupling diffraction and temperature effects. This led to identification of many suitable materials. Concurrently, many devices began development, including pulse compression filters, bandpass filters, resonators, oscillators, convolvers and matched filters for spread spectrum. In the 1970s, many of these became established in professional systems, and the SAW bandpass filter became a standard component for domestic TV. In the 1980s and 9Os, SAW responded to the new call for low-loss filters, particularly for mobile phones. With losses as low as 2 dB required (and subsequently achieved) at RF frequencies around 900 MHz, a raft of new technologies was developed. Additionally, for IF filters special techniques were evolved to reduce the physical size needed for narrow bandwidths. Such devices are now manufactured in very large quantities. In order to satisfy these needs, new types of surface wave, particularly transverse leaky waves, were investigated, and materials using such waves now have their place alongside more traditional materials.

Visual processing levels revealed by response latencies to changes in different visual attributes

Abstract: Visual latencies, and their variation with stimulus attributes, can provide information about the level in the visual system at which different attributes of the image are analysed, and decisions about them made. A change in the colour, structure or movement of a visual stimulus brings about a highly reproducible transient constriction of the pupil that probably depends on visual cortical mechanisms. We measured this transient response to changes in several attributes of visual stimuli, and also measured manual reaction times to the same stimulus changes. Through analysis of latencies, we hoped to establish whether changes in different stimulus attributes were processed by mechanisms at the same or different levels in the visual pathway. Pupil responses to a change in spatial structure or colour are almost identical, but both are ca. 40 ms slower than those to a change in light flux, which are thought to depend largely on subcortical pathways. Manual reaction times to a change in spatial structure or colour, or to the onset of coherent movement, differ reliably, and all are longer than the reaction time to a change in light flux. On average, observers take 184 ms to detect a change in light flux, 6 ms more to detect the onset of a grating, 30 ms more to detect a change in colour, and 37 ms more to detect the onset of coherent motion. The pattern of latency variation for pupil responses and reaction times suggests that the mechanisms that trigger the responses lie at different levels in cortex. Given our present knowledge of visual cortical organization, the long reaction time to the change in motion is surprising. The range of reaction times across different stimuli is consistent with decisions about the onset of a grating being made in V1 and decisions about the change in colour or change in motion being made in V4.

The Reliability of Retrospective Unemployment History Data

Abstract: This paper sets out to examine the reliability of data on men's and women's past experiences of unemployment spells which has been gained by asking individuals to recall these spells and the dates of their occurrence. Surveys seek individuals' history data either to gain information about the initial conditions of respondents, or to examine these histories in their own right. It is much less expensive to collect data about individuals' histories by asking them to recall their experiences than it is to collect the same data from a panel survey over many years. However, important questions arise concerning the reliability and validity of data collected by the recall method. Reviews of the tests carried out on recall data show that there are some important lessons to learn, particularly when individuals are being asked to recall experiences short in duration and low in importance (Dex 1995). Validity is difficult to assess. This paper seeks to extend the body of knowledge about the reliability of recall data on individuals' unemployment histories by providing empirical data on two large-scale surveys which collected similar data on unemployment histories from large numbers of British adults in the early 1990s; Wave 2 (1992) of the British Household Panel Study (BHPS) and the 1994 Family and Working Lives Survey (FWLS).

Sunbird surprise for syndromes

Abstract: Predictions can be made about how a given plant might be pollinated by looking at its morphology, colour, nectar and odour. But scientists are increasingly finding that these predictions aren't reliable. The latest example is that ofMicroloma sagittatum, a member of the milkweed family, which, against all expectations, has been found to be pollinated by the South African sunbird Nectarinia chalybea.

Aural landscape: musical space

Abstract: This paper seeks to examine how sound in general (and electroacoustic music in particular) can evoke a sense of being and place which may be strongly related to our visual experience. The auditory system has evolved to seek the reasons for the soundfield it encounters and this property cannot meaningfully be ignored by composers in this medium. The acousmatic condition stimulates and enhances this response. The science of acoustics cannot any longer alone explain sound phenomena and requires psychological and ecological dimensions. The idea of the ‘frame’ is developed from large-scale to small-scale soundfields: ‘landscape’, ‘arena’ and ‘stage’ are seen to be flexible components of this approach to composition. The paper concludes that a mature relationship of audio and visual art forms requires a greater acknowledgement of these attributes of sound.

Problem domain categories in requirements engineering

Abstract: Requirements engineering is the complex technical, social and cognitive process which produces requirements for a software-intensive system. However, little is understood about the problem domains for which these software-intensive systems are developed. Card sorting was used to determine mental categories of problem domains to inform design of a library of semi-formal, reusable object system models. Card sorting is a knowledge elicitation technique effective for eliciting mental categories from subjects who sort concepts such as objects or problems into categories. In NATURE, we anticipate better reuse if object system models in NATURE's database correspond to natural mental categories elicited using card sorting from experienced software engineers. Results led to some revision of the structure and contents of several models and how these models might be retrieved and used.

Nurses' responses to severity dependent errors: a study of the causal attributions made by nurses following an error.

Abstract: Attribution theory attempts to understand how people explain events and their own role in them, particularly events which are unusual or unpleasant. Based on previous studies on attributions, it was suggested that nurses would make more external attributions (i.e. blaming others or the environment) following an error with a serious outcome than one with a non-serious outcome. This would in turn suggest that they might be less likely to respond constructively and learn from serious errors. Sixty nurses were approached for this study. They were divided into two groups. One group (30 subjects) completed a questionnaire on the responses to a description of an error with a non-serious outcome and the second group (also 30 subjects) responded to questions to an identical error but with a serious outcome. The findings from this study indicated that nurses behaved in an atypical manner in response to making an error. Although both groups of nurses tended to make slightly more internal attributions for the error, indicating that they are likely to take responsibility for their error, those nurses in the serious outcome condition blamed themselves more for the error. This may be due to the strong professional ethos which exists amongst nurses that expects them to take responsibility for their actions. This would inevitably include any error that they may make in the course of giving care. The conclusion that can be drawn is that nurses might be quite receptive to making constructive changes in their practice following an error, provided this situation is managed properly.

The UK Landfill Tax : an analysis of its contribution to sustainable waste management

Abstract: The UK Government in October 1996 introduced a Landfill Tax to ensure that landfill waste disposal is properly priced so as to reflect its environmental cost and to help promote a more sustainable approach to waste management in which less waste is produced, reused or recycled. The UK Customs and Excise have recently reviewed the tax and the report indicates that there has been a modest reduction in waste going to landfill by industry but not households. It is submitted that for there to be a significant move towards a more sustainable approach to waste management to meet the targets set in the National Strategy the tax should be higher and the money raised by the tax should be invested to make alternatives to landfill cheaper and more readily available. It is also submitted that the Tax Credit Scheme, introduced as a means of enabling some of the tax to be invested to promote better waste management, is inadequately funded and the money is inappropriately focused. Following an examination of the projects and contributions made under the Scheme it is found that most of the contributions are not made towards projects which will fulfil the UK Government's perceived purposes. It is further submitted that there needs to be a more rational approach to waste management and legislation in Philadelphia forms a good case study of such an approach

Code growth, explicitly defined introns, and alternative selection schemes

Abstract: Previous work on introns and code growth in genetic programming is expanded on and tested experimentally. Explicitly defined introns are introduced to tree-based representations as an aid to measuring and evaluating intron behavior. Although it is shown that introns do create code growth, they are not its only cause. Removing introns merely decreases the growth rate; it does not eliminate it. By systematically negating various forms of intron behavior, a deeper understanding of the causes of code growth is obtained, leading to the development of a system that keeps unnecessary bloat to a minimum. Alternative selection schemes and recombination operators are examined and improvements demonstrated over the standard selection methods in terms of both performance and parsimony.

Enhancing the customer experience: contributions from information technology

Abstract: Consumers in a wide range of contexts whether purchasing goods or services are increasingly using technology. The role of people in the delivery of services is diminishing as companies strive to lower costs and consumers become less inclined to wait or queue. Through a number of case studies, the impact of technology in the provision of services is scrutinised and the common characteristics of the service experience in such applications are identified. As customers become more proficient at taking on an IT role, traditional models of the service experience may need to be revisited. Specifically, models will need to reflect a greater participation by the customer, a diminishing role for service personnel, and the blurring of the back and front office divide.