Showing papers by "Keele University published in 2002"

Preliminary guidelines for empirical research in software engineering

Abstract: Empirical software engineering research needs research guidelines to improve the research and reporting processes. We propose a preliminary set of research guidelines aimed at stimulating discussion among software researchers. They are based on a review of research guidelines developed for medical researchers and on our own experience in doing and reviewing software engineering research. The guidelines are intended to assist researchers, reviewers, and meta-analysts in designing, conducting, and evaluating empirical studies. Editorial boards of software engineering journals may wish to use our recommendations as a basis for developing guidelines for reviewers and for framing policies for dealing with the design, data collection, and analysis and reporting of empirical studies.

On Choosing and Bounding Probability Metrics

Abstract: Le choix de metrique de probabilite est une decision tres importante lorsqu'on etudie la convergence des mesures. Nous vous fournissons avec un sommaire de plusieurs metriques/distances de probabilite couramment utilisees par des statisticiens(nes) at par des probabilistes, ainsi que certains nouveaux resultats qui se rapportent a leurs bornes. Avoir connaissance d'autres metriques peut vous fournir avec un moyen de deriver des bornes pour une autre metrique dans un probleme applique. Le fait de prendre en consideration plusieurs metriques vous permettra d'approcher des problemes d'une maniere differente. Ainsi, nous vous demontrons que les taux de convergence peuvent dependre de facon importante sur votre choix de metrique. Il est donc important de tout considerer lorsqu'on doit choisir une metrique.

What does 'access to health care' mean?:

Abstract: Facilitating access is concerned with helping people to command appropriate health care resources in order to preserve or improve their health. Access is a complex concept and at least four aspects require evaluation. If services are available and there is an adequate supply of services, then the opportunity to obtain health care exists, and a population may 'have access' to services. The extent to which a population 'gains access' also depends on financial, organisational and social or cultural barriers that limit the utilisation of services. Thus access measured in terms of utilisation is dependent on the affordability, physical accessibility and acceptability of services and not merely adequacy of supply. Services available must be relevant and effective if the population is to 'gain access to satisfactory health outcomes'. The availability of services, and barriers to access, have to be considered in the context of the differing perspectives, health needs and material and cultural settings of diverse groups in society. Equity of access may be measured in terms of the availability, utilisation or outcomes of services. Both horizontal and vertical dimensions of equity require consideration.

The origin of subdwarf B stars – I. The formation channels

Abstract: Subdwarf B (sdB) stars (and related sdO/sdOB stars) are believed to be helium-core-burning objects with very thin hydrogen-rich envelopes. In recent years it has become increasingly clear from observational surveys that a large fraction of these objects are members of binary systems. To understand their formation better, we present the results of a detailed investigation of the three main binary evolution channels that can lead to the formation of sdB stars: the common-envelope (CE) ejection channel, the stable Roche lobe overflow (RLOF) channel, and the double helium white dwarfs (WDs) merger channel. The CE ejection channel leads to the formation of sdB stars in short-period binaries with typical orbital periods between 0.1 and 10 d, very thin hydrogen-rich envelopes and a mass distribution sharply peaked around similar to0.46 M-.. On the other hand, under the assumption that all mass transferred is soon lost, the stable RLOF channel produces sdB stars with similar masses but long orbital periods (400-1500 d) and with rather thick hydrogen-rich envelopes. The merger channel gives rise to single sdB stars whose hydrogen-rich envelopes are extremely thin but which have a fairly wide distribution of masses (0.4-0.65 M-.). We obtained the conditions for the formation of sdB stars from each of these channels using detailed stellar and binary evolution calculations where we modelled the detailed evolution of sdB stars and carried out simplified binary population synthesis simulations. The observed period distribution of sdB stars in compact binaries strongly constrains the CE ejection parameters. The best fits to the observations are obtained for very efficient CE ejection where the envelope ionization energy is included, consistent with previous results. We also present the distribution of sdB stars in the T (eff) -log g diagram, the Hertzsprung-Russell diagram and the distribution of mass functions.

Informal insurance arrangements with limited commitment: Theory and evidence from village economies

Abstract: Recent work on consumption allocations in village economies finds that idiosyncratic variation in consumption is systematically related to idiosyncratic variation in income, thus rejecting the hypothesis of full risk-pooling. We attempt to explain these observations by adding limited commitment as an impediment to risk-pooling. We provide a general dynamic model and completely characterise efficient informal insurance arrangements constrained by limited commitment, and test the model using data from three Indian villages. We find that the model can fully explain the dynamic response of consumption to income, but that it fails to explain the distribution of consumption across households.

Folk devils and moral panics ’Left idealism’ reconsidered

Abstract: This article is intended as an attack on Jock Young’s use of the term ‘left idealism’—that distillation of every 1960s hysteria and radicalchic inanity—to describe and to castigate the moral, polit...

Autologous chondrocyte implantation for cartilage repair: monitoring its success by magnetic resonance imaging and histology

Abstract: Autologous chondrocyte implantation is being used increasingly for the treatment of cartilage defects. In spite of this, there has been a paucity of objective, standardised assessment of the outcome and quality of repair tissue formed. We have investigated patients treated with autologous chondrocyte implantation (ACI), some in conjunction with mosaicplasty, and developed objective, semiquantitative scoring schemes to monitor the repair tissue using MRI and histology. Results indicate repair tissue to be on average 2.5 mm thick. It was of varying morphology ranging from predominantly hyaline in 22% of biopsy specimens, mixed in 48%, through to predominantly fibrocartilage, in 30%, apparently improving with increasing time postgraft. Repair tissue was well integrated with the host tissue in all aspects viewed. MRI scans provide a useful assessment of properties of the whole graft area and adjacent tissue and is a noninvasive technique for long-term follow-up. It correlated with histology (P = 0.02) in patients treated with ACI alone.

Principles of survey research: part 5: populations and samples

Abstract: This article is the fifth installment of our series of articles on survey research. In it, we discuss what we mean by a population and a sample and the implications of each for survey research. We provide examples of correct and incorrect sampling techniques used in software engineering surveys.

Europeanization and Political Parties Towards a Framework for Analysis

Abstract: Europeanization is a term used to describe the effects of European integration on the politics and policies of its member states as well as the process of enhancing European-level political institu...

Quantitative Review of Operative and Nonoperative Management of Achilles Tendon Ruptures

Abstract: Background: There is no consensus on the best method for management of acute Achilles tendon ruptures. Individual preferences, drawn from experience and study, determine whether treatment is operative or nonoperative.Purpose: Our goal was to review the literature to try to determine what management method was the most popular and effective. We wanted to ascertain the best results in terms of complication rates and patient outcomes.Study Design: Retrospective review of retrospectively and prospectively collected data.Methods: We analyzed 125 articles in peer-reviewed journals for year of publication, patient numbers, sex, management method, follow-up complications, and patient satisfaction. Each article was graded using a validated methods score. Methods, patient satisfaction, and complication rates were correlated with the year each article was published.Results: Skin-healing complications were lowest in conservatively managed patients (3 of 578, 0.5%) and highest in open repair and immobilized patients (...

Marketing, the consumer society and hedonism

Abstract: Marketing is commonly assumed to be responsible for the consumer society with its hedonistic lifestyle and for undermining other cultures by its materialistic stance. This, for many critics, is the dark side of consumer marketing, undermining its ethical standing. This paper considers the connection between marketing, the consumer society, globalization and the hedonistic lifestyle, and whether marketing is guilty as charged. After all, anything that affects the image of marketing as a profession is important, as this influences both recruitment and social acceptance.

Vegetation stress detection through chlorophyll a + b estimation and fluorescence effects on hyperspectral imagery.

Abstract: Physical principles applied to remote sensing data are key to successfully quantifying vegetation physiological condition from the study of the light interaction with the canopy under observation. We used the fluorescence-reflectance-transmittance (FRT) and PROSPECT leaf models to simulate reflectance as a function of leaf biochemical and fluorescence variables. A series of laboratory measurements of spectral reflectance at leaf and canopy levels and a modeling study were conducted, demonstrating that effects of chlorophyll fluorescence (CF) can be detected by remote sensing. The coupled FRT and PROSPECT model enabled CF and chlorophyll a + b (Ca + b) content to be estimated by inversion. Laboratory measurements of leaf reflectance (r) and transmittance (t) from leaves with constant Ca + b allowed the study of CF effects on specific fluorescence-sensitive indices calculated in the Photosystem I (PS-I) and Photosystem II (PS-II) optical region, such as the curvature index [CUR; (R675.R690)/R2(683)]. Dark-adapted and steady-state fluorescence measurements, such as the ratio of variable to maximal fluorescence (Fv/Fm), steady state maximal fluorescence (F'm), steady state fluorescence (Ft), and the effective quantum yield (delta F/F'm) are accurately estimated by inverting the FRT-PROSPECT model. A double peak in the derivative reflectance (DR) was related to increased CF and Ca + b concentration. These results were consistent with imagery collected with a compact airborne spectrographic imager (CASI) sensor from sites of sugar maple (Acer saccharum Marshall) of high and low stress conditions, showing a double peak on canopy derivative reflectance in the red-edge spectral region. We developed a derivative chlorophyll index (DCI; calculated as D705/D722), a function of the combined effects of CF and Ca + b content, and used it to detect vegetation stress.

‘It's Taking Me a Long Time but I'll Get There in the End’: Mature students on access courses and higher education choice

Abstract: The UK policy rhetoric of commitment to widening access to higher education has identified mature students as playing a pivotal role in the expansion and reform of higher education The article draws on the experiences of 23 mature access students in an inner London further education college in order to explore the range of opportunities and constraints mature students confront in their efforts to make the transition to higher education In particular, the article focuses on the narratives of the seven students who failed to complete the access course It is argued that complexities of ethnicity, gender and marital status intersect with, and compound, the consequences of class, making the transition process particularly difficult for working-class, lone mothers The article concludes that if the Government's 'New Learning Age' is not to reproduce past educational inequalities, then the rhetoric on widening participation needs to move beyond rhetoric into policies which provide possibilities for realisation

Meta- and pooled analyses of the effects of glutathione S-transferase M1 polymorphisms and smoking on lung cancer risk

Abstract: Susceptibility to lung cancer may in part be attributable to inter-individual variability in metabolic activation or detoxification of tobacco carcinogens. The glutathione S-transferase M1 (GSTM1) genetic polymorphism has been extensively studied in this context; two recent meta-analyses of case-control studies suggested an association between GSTM1 deletion and lung cancer. At least 15 studies have been published after these overviews. We undertook a new meta-analysis to summarize the results of 43 published case-control studies including >18 000 individuals. A slight excess of risk of lung cancer for individuals with the GSTM1 null genotype was found (odds ratio (OR) = 1.17, 95% confidence interval (CI) 1.07-1.27). No evidence of publication bias was found (P = 0.4), however, it is not easy to estimate the extent of such bias and we cannot rule out some degree of publication bias in our results. A pooled analysis of the original data of about 9500 subjects involved in 21 case-control studies from the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens (GSEC) data set was performed to assess the role of GSTM1 genotype as a modifier of the effect of smoking on lung cancer risk with adequate power. Analyses revealed no evidence of increased risk of lung cancer among carriers of the GSTM1 null genotype (age-, gender- and center-adjusted OR = 1.08, 95% CI 0.98-1.18) and no evidence of interaction between GSTM1 genotype and either smoking status or cumulative tobacco consumption.

Malaria Control with Genetically Manipulated Insect Vectors

Abstract: At a recent workshop, experts discussed the benefits, risks, and research priorities associated with using genetically manipulated insects in the control of vector-borne diseases.

An overview of three different approaches to the interpretation of qualitative data. Part 1: Theoretical issues.

Abstract: In this paper, the first of two, Helena Priest, Paula Roberts and Leslie Woods discuss the essential features and methods inherent within three approaches to the interpretation of qualitative data. An overview of three methodologies commonly used in nursing and healthcare research is presented: grounded theory, qualitative content analysis and narrative analysis. The paper considers the philosophical bases of the three methods and the principles inherent within each analytical approach. Key stages and steps are presented and described.

Systematic review of randomized controlled trials of nonpharmacological interventions for fibromyalgia.

Abstract: Objective Little is known of the effectiveness of nonpharmacological interventions for fibromyalgia syndrome (FMS). The authors therefore carried out a systematic review from 1980 to May 2000 of randomized controlled trials (RCTs) of nonpharmacological interventions for FMS. Method A search of computerized databases was supplemented by hand searching of bibliographies of key publications. The methodological quality of studies included in the review was evaluated independently by two researchers according to a set of formal criteria. Discrepancies in scoring were resolved through discussion. Results The review yielded 25 RCTs, and the main categories of interventions tested in the studies were exercise therapy, educational intervention, relaxation therapy, cognitive-behavioral therapy, acupuncture, and forms of hydrotherapy. Methodological quality of studies was fairly low (mean score = 49.5/100). Most studies had small samples (median for individual treatment groups after randomization = 20), and the mean power of the studies to detect a medium effect ( > or = 0.5) was 0.36. Sixteen studies had blinded outcome assessment, but patients were blinded in only 6 studies. The median longest follow-up was 16 weeks. Statistically significant between-group differences on at least one outcome variable were reported in 17 of the 24 studies. Conclusions The varying combinations of interventions studied in the RCTs and the wide range of outcome measures used make it hard to form conclusions across studies. Strong evidence did not emerge in respect to any single intervention, though preliminary support of moderate strength existed for aerobic exercise. There is a need for larger, more methodologically rigorous RCTs in this area.

Tendinopathy of tendo achillis.

Abstract: study, however, 31% of 58 patients with this condition did not participate in vigorous physical activity. 3 In this article, we have concentrated on tendinopathy of the main body of tendo Achillis. We have not dealt with Haglund's condition, insertional tendinopathy, or with lesions of the myotendinous junction. Anatomy. The gastrocnemius muscle merges with the soleus to form tendo Achillis. 4 It has a round upper part and is relatively flat in its distal 4 cm. Its fibres spiral through 90°, increasing the release of stored energy during locomotion. 5 Tendo Achillis is enveloped by a paratenon, originating from the deep fascia of the leg, the fascia cruris. Blood flow in the tendon increases considerably with exercise, probably due to the marked rise in the negative tissue pressure

Measuring the population impact of knee pain and disability with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

Abstract: This study has used the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in an unsolicited postal questionnaire to investigate the impact of knee pain and disability in the general older population. The study provides WOMAC population data for those aged over 50 and demographic and psychosocial associations with severity of WOMAC scores. A pilot survey (n=240) and repeatability study (n=80) were undertaken to test completion of the WOMAC in this new setting. The main questionnaire was mailed to 8,995 men and women aged over 50 registered with three general practices in North Staffordshire, UK. Completion rates for WOMAC items were high. Substantial reliability was found for pain and physical function scales (both >0.80). Fourteen percent of the over 50 population in this study had severe knee pain, 20% had severe difficulty with at least one area of physical functioning, 12% had both. The strongest link with severe difficulty with physical functioning was chronicity (odds ratio (OR)=6.49, 95% CI 4.65, 9.04). Other independent links were age over 75 years (odds ratio (OR)=4.11, 95% confidence interval (CI) 3.03, 5.58), depression (OR=2.80, 95% CI 2.22, 3.54), bilateral knee injury (OR=2.23, 95% CI 1.63, 3.06) and body mass index>30 (OR=2.00, 95% CI 1.51, 2.64). Similar associations were found for severe pain. The findings suggest that the WOMAC is a reliable measure for use in postal surveys. It has advantages over other instruments when measuring pain and physical function difficulty related to the knee. Chronicity, older age, injury, obesity and depression were all linked with higher WOMAC scores for knee pain severity and disability among knee pain sufferers in the general older population.

Detecting binocular half-occlusions: empirical comparisons of five approaches

Abstract: Binocular half-occlusion points are those that are visible in one of the two views provided by a binocular imaging system. Due to their importance in binocular matching as well as, subsequent interpretation tasks, a number of approaches have been developed for dealing with such points. In the current paper, we consider five methods that explicitly detect half-occlusions and report on a more uniform comparison than has previously been performed. Taking a disparity image and its associated match goodness image as input, we generate images that show the half-occluded points in the underlying scene. We quantitatively and qualitatively compare these methods under a variety of conditions.

Principles of survey research part 2: designing a survey

Abstract: This second article of our series looks at the process of designing a survey. The design process begins with reviewing the objectives, examining the target population identified by the objectives, and deciding how best to obtain the information needed to address those objectives. However, we also need to consider factors such as determining the appropriate sample size and ensuring the largest possible response rate.To illustrate our ideas, we use the three surveys described in Part 1 of this series to suggest good and bad practice in software engineering survey research.

Temporal Aggregation and the Power of Cointegration Tests: a Monte Carlo Study*

Abstract: The effect of time-aggregation on the power of commonly used tests for cointegration is studied with the Monte Carlo method. The results suggest that, for a given span, a higher frequency of observation can add substantially to test power. Also, Engle and Granger's (1987) ADF test leads overall to the highest and most stable powers for typical finite sample sizes and likely data generating processes encountered by practitioners. Copyright 2002 by Blackwell Publishing Ltd

Emotions and criminal justice

Abstract: During the last decade, a process of ‘emotionalization of law’ has spread around the globe, changing the criminal justice system in many ways. Anger, disgust and shame are perceived as ‘valuable barometers of social morality’ and brought back to criminal procedures. The ‘return of emotions’ to penal law and criminal justice is linked to and illuminates the moral imagination of late modern societies. This article seeks to address two facets of the ‘return of emotions’ to criminal justice. The first part explores the changes in the public sphere and in the pattern of emotional culture in late modern societies that are responsible for the reemotionalization of the penal realm. In the second part, problems that emerge in the criminal justice system are addressed. Bringing emotions back involves profound problems that go beyond the mere instrumental use of emotions in criminal justice, or a restricted perspective of ‘what works’. Three ‘core’ problems—and associated—questions are discussed: first, are emotiona...